Article

# Are there three main subgroups within the patellofemoral pain population? A detailed characterisation study of 127 patients to help develop targeted Intervention (TIPPs)

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## Abstract

Background: Current multimodal approaches for the management of non-specific patellofemoral pain are not optimal, however, targeted intervention for subgroups could improve patient outcomes. This study explores whether subgrouping of non-specific patellofemoral pain patients, using a series of low cost simple clinical tests, is possible. Method: The exclusivity and clinical importance of potential subgroups was assessed by applying à priori test thresholds (1 SD) from seven clinical tests in a sample of adult patients with non-specific patellofemoral pain. Hierarchical clustering and latent profile analysis, were used to gain additional insights into subgroups using data from the same clinical tests. Results: 130 participants were recruited, 127 had complete data: 84 (66%) female, mean age 26 years (SD 5.7) and mean body mass index 25.4 (SD 5.83), median (IQR) time between onset of pain and assessment was 24 (7-60) months. Potential subgroups defined by the à priori test thresholds were not mutually exclusive and patients frequently fell into multiple subgroups. Using hierarchical clustering and latent profile analysis three subgroups were identified using 6 of the 7 clinical tests. These subgroups were given the following nomenclature: (1) 'strong', (2) 'weak and tighter' and (3) 'weak and pronated foot'. Conclusions: We conclude that three subgroups of patellofemoral patients may exist based on the results of six clinical tests which are feasible to perform in routine clinical practice. Further research is needed to validate these findings in other data sets and, if supported by external validation, to see if targeted interventions for these subgroups improve patient outcomes.

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... Patellofemoral pain syndrome (PPS) is one of the most common knee joint disorders and accounts for 11-17% of clinical complaints in relation to this joint (Crossley et al., 2016). It affects 20% of the general population, primarily in the age range of 18-35 years (Selfe et al., 2016). Individuals with PPS may manifest strong signs and symptoms of anxiety, depression, catastrophization and kinesiophobia, which may be correlated to increased pain and reduced physical function (Maclachlan et al., 2017). ...
... It is known that 90% of PPS patients also have symptoms four years after diagnosis and only 6% do not have symptoms in 16 years (Selfe et al., 2016). Despite the relevance of studies involving PPS, the etiological factors have not been properly established. ...
... The PPS group was not stratified into patients with weak quadriceps muscles and/or lateral rotators; therefore, anterior knee pain symptoms were considered. However, stratification into subgroups is also found in other studies (Selfe et al., 2016). Other aspects to be considered relate to using only the lateral hip rotation position and not isometric contraction of these muscles, which could have minimized the action of the lateral rotator muscles as well as the GMed. ...
... In a recently published subgrouping study (TIPPS), we identified three subgroups among 127 adults aged 18 to 40 years with PFP using six clinical tests routinely available in practice [11]. These subgroups included a 'weak and tight' (39%) subgroup, a 'weak and pronated feet' (39%) subgroup and a 'strong' (22%) subgroup. ...
... One of the clinical tests used in TIPPS was the total medial-lateral patellar glide test. The mean patellar mobility using this test was similar in the 'weak and tight' subgroup and the 'strong' subgroup but it was significantly higher in the 'weak and pronated' subgroup [11]. One difficulty in interpreting this data clinically was the limited published data on normative means, standard deviations or ranges. ...
... However, others have also repeated the patellar mobility measurement three times [13,14]. This is also usual practice for many of the other clinical tests used in the TIPPS study and in clinical practice, such as measuring quadriceps strength, which involves taking the average of three measurements to achieve stable values [11]. ...
Article
INTRODUCTION: Patellar mobility is often routinely assessed in people with patellofemoral pain (PFP) in clinical practice. This study assessed the stability of the data when measuring patellar mobility using the total medial-lateral patellar glide test across multiple repetitions. It also compared patellar mobility of people with healthy knees to people with PFP and within subgroups of PFP. METHODS: Twenty-two people without knee problems underwent five repetitions of the total medial-lateral patellar glide test. Differences in mean value for each repetition and the intra-class correlations (ICC) between the first assessment and the average values of additional repetitions were calculated. Mean patellar mobility was compared with 127 participants with PFP who took part in a previously published subgrouping study. Differences between the healthy knee group and PFP subgroups were also explored using a one-way ANOVA with pairwise comparisons. RESULTS: The mean patellar mobility in healthy individuals was 16.4mm (SD 5.3), difference in mean patellar mobility across repetitions was minimal and the ICC ranged between 0.93 and 0.95. People with PFP had significantly lower patellar mobility than the healthy knee group. Two of three PFP subgroups had statistically significantly lower mean patellar mobility (difference in mean -5.6mm and -6.5mm; P<0.001). DISCUSSION: A single medial-lateral patellar glide test appears as informative as repeated tests in practice. One off measures of patellar mobility using the total medial-lateral patellar glide test may identify subgroups of PFP to help guide treatment in clinical practice. Further work is needed to assess other reliability parameters for this measure.
... There are 3 subgroups in the PFP population: strong, weak and tight, and weak and pronated foot. 40 The purpose of this study was to assess the clinical outcomes of targeted treatments designed according to the characteristics of these 3 subgroups of PFP patients. 40 The hypotheses were that the assessment and subgroup classification would be clinically feasible and that targeted treatments designed according to the characteristics of the 3 subgroups of PFP patients would show clinical benefits over and above a multimodal intervention. ...
... 40 The purpose of this study was to assess the clinical outcomes of targeted treatments designed according to the characteristics of these 3 subgroups of PFP patients. 40 The hypotheses were that the assessment and subgroup classification would be clinically feasible and that targeted treatments designed according to the characteristics of the 3 subgroups of PFP patients would show clinical benefits over and above a multimodal intervention. ...
... Eligibility criteria were based on previously defined PFP criteria. 6,40,47 Patients were excluded if they had any of the following: previous knee surgery, clinical evidence of ligamentous instability and/or internal derangement, a history of patellar subluxation or dislocation, joint effusion, true knee joint locking and/or giving way, bursitis, patellar or iliotibial tract tendinopathy, Osgood-Schlatter disease, Sinding-Larsen-Johansson syndrome, muscle tears or symptomatic knee plicae, another serious comorbidity that would preclude or affect compliance with the assessment, or were pregnant. Quadriceps and hip abductor muscle strength, 30,50 patellar glide test, 44,54 quadriceps length, 53 gastrocnemius length, 53 and foot posture index 36 assessments were performed to classify all consenting patients into 1 of 3 subgroups (strong, weak and tight, and weak and pronated foot) using the algorithm derived from the work by Selfe et al. 40 ...
Article
Background Targeted intervention for subgroups is a promising approach for the management of patellofemoral pain. Hypothesis Treatment designed according to subgroups will improve clinical outcomes in patients unresponsive to multimodal treatment. Study Design Prospective crossover intervention. Level of Evidence Level 3. Methods Patients with patellofemoral pain (PFP; n = 61; mean age, 27 ± 9 years) were enrolled. Patients with PFP received standard multimodal treatment 3 times a week for 6 weeks. Patients not responding to multimodal treatment were then classified into 1 of 3 subgroups (strong, weak and tight, and weak and pronated foot) using 6 simple clinical tests. They were subsequently administered 6 further weeks of targeted intervention, designed according to subgroup characteristics. Visual analog scale (VAS), perception of recovery scale (PRS), 5-Level European Quality 5 Dimensions (EQ-5D-5L), and self-reported version of the Leeds Assessment of Neuropathic Symptoms and Signs scale (S-LANSS) were used to assess pain, knee function, and quality of life before and after the interventions. Results In total, 34% (n = 21) of patients demonstrated recovery after multimodal treatment. However, over 70% (n = 29/40) of nonresponders demonstrated recovery after targeted treatment. The VAS, PRS, S-LANSS, and EQ-5D-5L scores improved significantly after targeted intervention compared with after multimodal treatment ( P < 0.001). The VAS score at rest was significantly lower in the “weak and pronated foot” and the “weak and tight” subgroups ( P = 0.011 and P = 0.008, respectively). Posttreatment pain intensity on activity was significantly lower in the “strong” subgroup ( P = 0.006). Conclusion Targeted treatment designed according to subgroup characteristics improves clinical outcomes in patients unresponsive to multimodal treatment. Clinical Relevance Targeted intervention could be easily implemented after 6 simple clinical assessment tests to subgroup patients into 1 of 3 subgroups (strong, weak and tight, and weak and pronated foot). Targeted interventions applied according to the characteristics of these subgroups have more beneficial treatment effects than a current multimodal treatment program.
... A relatively simple illustration could be to determine the exact interplay between psychological risk profiles and training behaviors. Future research could also focus on targeted prevention and management practices involving psychological risk profiles to reduce adverse outcomes of running, as highlighted in the current person-centered approach (see also Selfe et al., 2016). Pinpointing optimal thresholds for assigning runners to certain profiles and optimizing the use of subjective psychosocial measures in assessing athlete well-being (see Saw et al., 2015) may prove a worthwhile new avenue. ...
... Psychological risk profiles may help identify vulnerable runners and thereby prove useful for targeted early prevention practices (e.g., Selfe et al., 2016). Our risk profiles exhibit notable differences in their potential to enable long-term sustainable running. ...
... Extending this reasoning, we argued that it is likely that these latent subgroups react differently to an intervention, in a similar fashion to how individualized (e.g., Kozinc & Sarabon, 2017) and subgrouping approaches (e.g., Selfe et al., 2016) have been advocated to improve intervention effectiveness. If effects of the app intervention indeed differ across subgroups, then this further incentivizes individualized approaches. ...
Thesis
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This dissertation discusses whether specific psychological factors contribute to our ability to understand and optimize the health outcomes of running. It provides information on coping, psychological risk profiles, an app intervention, and a self-assessment tool to determine one's risk for adverse health outcomes as a runner.
... This is also consistent with the recommended goal of achieving a 50% reduction in pain when using tailored patellar taping to control patellar tilt, translation, and spin. 2 According to this value, Mulligan knee taping produced clinically significant pain reductions in 26% to 42% of participants, depending on the task being assessed. This highlights the need for a tailored approach when using taping to optimize the management of PFP 4,16,25,42 and is consistent with how Mulligan knee taping is used clinically, where it is only utilized if it produces a clinically significant reduction in pain. 22,32 Consistent with our hypothesis, elastic tape was significantly more comfortable than rigid tape both in general and during activity. ...
... Second, recent literature has suggested that patients with PFP may be subgrouped according to the factors that contribute to their presentation to tailor and optimize management and that patellar malpositioning and/or maltracking is perhaps only relevant for a subset of those with PFP. 16,38,42 The current study did not recruit according to this concept, and thus, it remains unknown whether the Mulligan knee taping technique is more effective in those with evidence of maltracking. We suggest that this is another area for future research. ...
Article
Full-text available
... Previous studies have reported less hip adduction moment in people with moderate to severe knee OA compared to a control group (Astephen et al. 2008). This has led to a proposed hypothesis of decreased hip adduction moment as a result of hip abductor muscle weakness being an important factor in the progression of knee OA (Chang et al. 2005;Mundermann et al. 2005) and has been used as a predictive factor in subgroups in people with patellofemoral pain (Selfe et al. 2016). Small but nonsignificant differences were seen in hip abductor strength between limbs (1.2%), with an average hip abductor strength of 1.63 Nm/kg for NDL and 1.61 Nm/kg for DL, which represents symmetry in the hip abductor strength between NDL and DL. ...
... A side-lying position was adopted for the strength test in this study. Widler et al. (2009) reported that side lying is the most appropriate position to record the maximum GMed strength rather than using supine and standing positions, this technique was also used by Selfe et al. (2016) to define clinical subgroups in people with patellofemoral pain. The patterns of lateral trunk bending, pelvic obliquity, knee adduction moment, and GMed muscle activity were all similar between sides; therefore, this study showed no asymmetries in the measurements taken between the NDL and DL. ...
Article
Full-text available
The purpose of the study was to explore differences in the coronal biomechanics of the trunk, pelvis, hip, and knee joints, and gluteus medius muscle activity (GMed) during walking and step down from two riser heights. Joint kinematics and kinetics from 20 healthy participants were recorded using a 10-camera Qualisys system and force plates, and GMed EMG was recorded using a Delsys Trigno system. Hip abductor strength was measured using a hand-held dynamometer. Pelvic obliquity and lateral trunk bending excursions were significantly higher in walking than in step-down tasks. Significantly greater knee adduction moments were seen during both step-down tasks compared to level walking with significantly greater GMed activity. However, a significant interaction between side and task was seen for hip adduction moment, with step-down tasks showing lower hip moments than during walking, with greater peak hip moments being more apparent in the dominant limb. This suggests the GMed has a greater stabilizing role during the step-down tasks, although walking required a greater mechanical demand. Health professionals should expect to find less excursion of lateral trunk bending in step-down tasks compared to level walking and consider that GMed has different roles in these two tasks. ARTICLE HISTORY
... Thereby it can grasp complex interactions among variables that have been suggested to be essential in understanding the etiology of injuries in sports (Ivarsson & Stenling, 2019). Extending this reasoning, we argued that it is likely that these latent subgroups react differently to an intervention, in a similar fashion to how individualized (e.g., Kozinc & Sarabon, 2017) and subgrouping approaches (e.g., Selfe et al., 2016) has been advocated to improve intervention effectiveness. If effects of the app intervention indeed differ across subgroups, then this further incentivizes individualized approaches. ...
... Finally, both population-wide and high-risk prevention strategies have been argued to be necessary (Platt et al., 2017;Wilson et al., 2017). With the population approach already captured in the previous hypotheses, we aimed to explore the "individual" high-risk approach by determining the effects of the app across different risk profiles in runners, thereby investigating the potential for targeted intervention approaches (e.g., Selfe et al., 2016). ...
Article
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Runners have a high risk of getting injured compared to practitioners of other sports, and reducing this risk appears challenging. A possible solution may lie in the self-regulatory behavior of runners and their passion for running, which are promising predictors of runners' risk of running-related injuries (RRIs) and chronic fatigue. Therefore, in the present study, we investigated to what extent a mobile application (“app”), called REMBO, could reduce the risk of RRIs and chronic fatigue by externally supporting self-regulation in a personalized fashion. Long-distance runners (N = 425; 243 men, 182 women; Mage = 44.7 years), training for half and whole marathon distances, took part in our randomized controlled trial. Runners were randomly allocated to theintervention group with access to the app (n = 214) or to the control group with no access to the app (n = 211). We tested the effectiveness of the app according to the intention-to-treat protocol and via a dose-response analysis, finding no statistically significant effects with regard to RRIs and chronic fatigue. Furthermore, an exploratory latent risk profile subgroup analysis found no evidence that any reductions in RRIs or chronic fatigue due to the app intervention differed across low-risk, medium-risk, and high-risk psychological profiles of runners. Across our study, adherence was relatively low, reasons for which are discussed based on feedback from participants. In our discussion, we outline the implications of the app intervention not achieving its intended effect and list several recommendations that might steer toward more success in preventing RRIs and chronic fatigue in the future.
... The international consensus considering the high failure rate for treatment of PFP suggests that a paradigm shift towards identifying PFP subgroups and delivering stratified care is required [2,7,8]. Recently Selfe et al. have taken the first step towards this by identifying three distinct subgroups of patients with PFP, one of which was 'weak and pronated' partially defined by having a foot posture index (FPI) score of > 6, however, they did not conduct any intervention or investigate patient outcomes [9]. Studies on the effects of foot pronation on PFP have been limited to the recommendation of foot orthoses. ...
... The inclusion criteria were: both males and females between 25 to 55 years of age; no complaints of continuing knee pain (for at least six months and without trauma) in the bilateral pre-/retropatellar area, pain provoked by at least one activity from prolonged sitting, squatting, kneeling, or stair climbing and classifying as moderate (3.5-6.4) and severe ( 6.5) according to pain-Visual Analogue Scale (pVAS) [17], and categorized as 'weak and pronated' foot defined by a score from FPI of > 6 according to Selfe et al. [9]. Patients were excluded if they had a history of previous knee surgery, trauma, patellar dislocation or subluxation, tendinitis or bursitis, any other non-surgical interventions in the previous 6 months if they had intra-articular problems, involvement of ligaments or meniscus, knee pain or joint effusion due to rheumatic diseases and pregnancy, pain or tenderness of the plantar fascia and foot or a history of plantar fasciitis [18][19][20]. ...
Article
Background: Patellofemoral pain (PFP) is a common knee problem. The foot posture in a relaxed stance is reported as a distal factor of PFP. However, the effects of short foot exercise (SFE) on the knee and functional factors have not yet been investigated in patients with PFP. Objective: This study aimed to investigate the additional effects of SFE on knee pain, foot biomechanics, and lower extremity muscle strength in patients with PFP following a standard exercise program. Methods: Thirty patients with a 'weak and pronated' foot subgroup of PFP were randomized into a control group (ConG, n= 15) and a short foot exercise group (SFEG, n= 15) with concealed allocation and blinded to the group assignment. The program of ConG consisted of hip and knee strengthening and stretching exercises. SFEG program consisted of additional SFE. Both groups performed the supervised training protocol two times per week for 6 weeks. Assessment measures were pain visual analog scale (pVAS), Kujala Patellofemoral Score (KPS), navicular drop test (NDT), rearfoot angle (RA), foot posture index (FPI), and strength tests of the lower extremity muscles. Results: Both groups displayed decreases in pVAS scores, but it was only significant in favor of SFEG. NDT, RA, and FPI scores decreased in SFEG whereas they increased in ConG. There was a significant group-by-time interaction effect in hip extensor strength and between-group difference was found to be significantly in favor of SFEG. Conclusions: An intervention program consisting of additional SFE had positive effects on knee pain, navicular position, and rearfoot posture. An increase in the strength of the hip extensors may also be associated with stabilization with SFE.
... A significant number of patients who have PFP have been found to have lower levels of strength in their quadriceps and gluteal muscles than individuals without PFP [10]. However, research by Selfe et al. (2016) [11] identified a subgroup of PFP patients, predominantly males with higher levels of hip abductor and quadriceps strength who were classed as 'strong'. This might help to explain why some patients who receive evidence-based strengthening exercises continue to have poor outcomes. ...
... A significant number of patients who have PFP have been found to have lower levels of strength in their quadriceps and gluteal muscles than individuals without PFP [10]. However, research by Selfe et al. (2016) [11] identified a subgroup of PFP patients, predominantly males with higher levels of hip abductor and quadriceps strength who were classed as 'strong'. This might help to explain why some patients who receive evidence-based strengthening exercises continue to have poor outcomes. ...
Article
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OBJECTIVES: To assess the feasibility of a 30-minute education session for patients with patellofemoral pain on levels of catastrophizing and kinesiophobia. DESIGN: Randomised feasibility study SETTING: Three sites within a single NHS Organisation in England. PARTICIPANTS: Thirty-one adult patients were screened for inclusion, resulting in twenty-four who had a clinical diagnosis of patellofemoral pain being randomised equally to either the intervention or control group. INTERVENTION: Participants were randomised to either control or intervention conditions; both received standardized physiotherapy while the intervention/experimental group received a 30-minute educational session addressing causes of pain, beliefs about noise that comes from the joint, the impact of the pain on activity, the influence of other family members’ experience and beliefs about knee pain. Intervention participants were also given an education leaflet: ‘Managing My Patellofemoral Pain’. MAIN OUTCOMES: recruitment, retention, intervention fidelity. Patient reported outcome measures (PROMs): Knee injury and Osteoarthritis Outcome Score for patellofemoral pain and osteoarthritis (KOOS-PF), Pain Catastrophizing Scale (PCS) and Tampa Scale for Kinesiophobia (TSK). RESULTS: The study was successful in recruiting and retaining participants and was delivered as intended. In addition, sufficient clinical data were generated to calculate the required sample size for a future study of efficacy CONCLUSIONS: This study which featured a 30-minute education session targeting levels of catastrophizing and kinesiophobia is feasible and identified that the TSK may be the most appropriate PROMs for a future study of efficacy of this intervention. Allowing for a drop out of 20%as identified in similar studies, 86 participants (per arm) in a two-arm study would be required for a traditional randomised controlled trial design.
... A relatively simple illustration could be to determine the exact interplay between psychological risk profiles and training behaviors. Future research could also focus on targeted prevention and management practices, involving psychological risk profiles in order to reduce negative outcomes of running, as highlighted in the current person-centered approach (see also Selfe et al., 2016). Pinpointing optimal thresholds for assigning runners to certain profiles and optimizing the use of subjective psychosocial measures in assessing athlete well-being (see Saw et al., 2015) may prove a worthwhile new avenue. ...
... Psychological risk profiles may help identify vulnerable runners and thereby prove useful for targeted early prevention practices (e.g., Selfe et al., 2016). Our risk profiles exhibit strong differences in their potential to enable long-term sustainable running. ...
Article
Full-text available
Introduction: Consistently predicting adverse outcomes of long-distance running, such as running-related injuries (RRIs) and chronic fatigue, has proven to be a complicated matter. However, research suggests that a stronger focus on psychological factors of runners might provide further insights. Consequently, in this study, we explored the interplay between self-regulatory coping strategies and motivational aspects. Using a person-centered approach, we investigated whether latent psychological profiles of runners were associated with RRIs and chronic fatigue. Methods: Questionnaire data were gathered from Dutch recreational long-distance runners (N = 425) using a cross-sectional design. We determined whether specific psychological combinations (i.e., latent profiles) based on coping strategies (i.e., running-related resources and recovery) and motivational aspects (i.e., harmonious and obsessive passion) could be distinguished using latent profile analysis (LPA). The resulting profiles were tested for their associations with RRIs and chronic fatigue. Results: LPA revealed three different psychological risk profiles, termed the ‘low-risk’, ‘medium-risk’, and ‘high- risk’ profile. The low-risk profile showed low scores on obsessive passion and high scores on all recovery dimensions, whereas the high-risk profile resembled the opposite pattern. Furthermore, the low-risk profile showed significantly fewer RRIs and lower chronic fatigue scores than the high-risk profile. Discussion: The results reveal that (1) patterns of passion and coping strategies interact in defining different profiles and (2) that such profiles are indeed linked to RRIs and chronic fatigue. Utilizing profiles might enable targeted intervention and more effective preventative measures by pinpointing at-risk runners. Specific combinations of psychological aspects, as reflected by our profiles, thus appear a worthwhile direction to consider in understanding RRIs and chronic fatigue in long-distance running.
... Apesar de sua grande incidência, a etiologia da SDPF ainda é controversa. Diversos autores sugerem que seja multifatorial e relacionada com alterações no alinhamento patelofemoral, geradas por diversos fatores biomecânicos, como fraqueza do mecanismo extensor de joelho [3,[5][6][7], com possibilidade de desequilíbrio neuromuscular entre o vasto lateral (VL) e os vastos medial (VM) [8,9] e medial oblíquio (VMO) [10][11][12]. Bem como, por fraqueza da musculatura de tronco, abdutores e rotadores laterais de quadril, além de pronação excessiva do tornozelo [5,7,11]. ...
... Diversos autores sugerem que seja multifatorial e relacionada com alterações no alinhamento patelofemoral, geradas por diversos fatores biomecânicos, como fraqueza do mecanismo extensor de joelho [3,[5][6][7], com possibilidade de desequilíbrio neuromuscular entre o vasto lateral (VL) e os vastos medial (VM) [8,9] e medial oblíquio (VMO) [10][11][12]. Bem como, por fraqueza da musculatura de tronco, abdutores e rotadores laterais de quadril, além de pronação excessiva do tornozelo [5,7,11]. Fatores estes relacionados com a cinemática do valgo dinâmico de joelho [13][14][15][16][17][18][19][20][21]. ...
Article
... It is characterised by anterior knee pain and/or pain in the retropatellar and/or peripatellar region that typically increases with flexion-related activities such as squatting, kneeling, stair climbing and after prolonged sitting [2]. The underlying causes of PFPS are multifactorial and may be associated with biomechanical and or neurophysiological changes at the pelvis, hip, knee or ankle regions [48]. Numerous factors including a larger quadriceps (Q) angle [3], dynamic knee valgus [4], increased rear-foot eversion on heel strike [5] have been linked to the aetiology of PFPS. ...
Article
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Background: Taping is frequently used as part of the multi-modal management for patellofemoral pain syndrome (PFPS). McConnell Patellofemoral Joint Taping (PFJT) and Tibial Internal Rotation Limitation Taping (TIRLT) are proposed to be useful adjuncts to the management of PFPS. However, it is unclear if TIRLT offers similar benefits to PFJT, and its effect on pain and lower limb kinematics have not been investigated previously. Research question: What are the effects of TIRLT, PFJT and no taping on perceived pain and lower limb kinematics during a lunge and single leg squat (SLS) in people with PFPS? Methods: This cross-sectional study compared the effects of TIRLT, PFJT and no taping, on knee pain and lower limb kinematics during two pain-provoking movements in people with PFPS. Participants with PFPS (n = 23) performed a lunge and SLS under three randomised conditions: TIRLT, PFJT and no taping. The Codamotion system captured and analysed lower limb kinematic data in the sagittal, transverse and coronal planes. Peak knee pain intensity during the movement was assessed using the Numerical Rating Scale (NRS). Results: Participants reported significantly less pain with the TIRLT and PFJT techniques compared with no tape during the lunge (p = 0.005 and p = 0.011, respectively) and SLS (p= 0.002 and p = 0.001, respectively). There was no evidence of altered lower limb kinematics accompanying pain reductions with either taping technique. Significance: Both forms of taping may be useful adjuncts as the short-term benefit of pain relief may enable participation in more active forms of rehabilitation.
... Changes in the distribution of foot pressure, for example midfoot loading, has been associated with foot pronation and patellofemoral pain (Powers, 2003;Thijs, Van Tiggelen, Roosen, De Clercq, & Witvrouw, 2007). In addition, the static assessment of foot posture using the Foot Posture Index (Redmond, Crosbie, & Ouvrier, 2006) has been shown to be important in the prediction of clinical subgroups in people with patellofemoral pain (Selfe et al., 2016). Therefore, the use of foot pressure may allow an assessment of changes in loading strategy and dynamic postural control on the trail and lead limbs which could be performed in the competition arena. ...
Article
... The presence of subgroups within the PFP_iso and PFP_dis cohorts could explain the large variability found within studies for estimates of lateral maltracking (see Figures 6 and 7). In addition, patients within unique subgroups may have distinct causes of PFP, 54,55 which would suggest the need to stratify interventional strategies based on subgrouping patients. ...
Article
Background Patellar maltracking is widely accepted as an underlying mechanism of patellofemoral pain. However, methodological differences in the literature hinder our ability to generate a universal quantitative definition of pathological patellofemoral kinematics (patellar maltracking) in patellofemoral pain, leaving us unable to determine the cause of patellofemoral pain. Purpose To systematically review the literature to provide evidence regarding the influence of confounding variables on patellofemoral kinematics. Study Design Systematic review and random effects meta-analysis of control-case studies. Methods A literature search of case-control studies that evaluated patellofemoral kinematics at or near full extension and were written in English was conducted using Embase, PubMed, Scopus, and Web of Science up to September 2019. Cases were defined as patients with patellofemoral pain. Studies were eliminated if they lacked quantitative findings; had a primary aim to assess therapy efficacy; or included participants with osteoarthritis and/or previous trauma, pathology, or surgery. A quality assessment checklist was employed to evaluate each study. Meta-analyses were conducted to determine the influence of confounding variables on measures of patellofemoral kinematics. Results Forty studies met the selection criteria, with quality scores ranging from 13% to 81%. Patient characteristics, data acquisition, and measurement methods were the primary sources of methodological variability. Active quadriceps significantly increased lateral shift (standardized mean difference [SMD] shift = 0.33; P = .0102) and lateral tilt (SMD tilt = 0.43; P = .006) maltracking. Individuals with pain secondary to dislocation had greater effect sizes for lateral maltracking than had those with isolated patellofemoral pain (ΔSMD shift = 0.71, P = .0071; ΔSMD tilt = 1.38, P = .0055). Conclusion This review exposed large methodological variability across the literature, which not only hinders the generalization of results, but ultimately mitigates our understanding of the underlying mechanism of patellofemoral pain. Although our meta-analyses support the diagnostic value of maltracking in patellofemoral pain, the numerous distinct methods for measuring maltracking and the limited control for cofounding variables across the literature prohibit defining a single quantitative profile. Compliance with specific standards for anatomic and outcome measures must be addressed by the scientific and clinical community to establish methodological uniformity in this field.
... A number of factors are linked to poor long term outcomes, including longer symptom duration, bilateral symptoms, female sex, higher pain frequency and intensity, poorer function, and lower health and education levels . It is suggested that longer term outcomes may be improved through treatment that is more tailored to patient needs (Barton, Crossley, & Macri, 2018;Maclachlan, Collins, Matthews, Hodges, & Vicenzino, 2017;Selfe et al., 2016) and preferences . ...
Article
Objectives: To evaluate the feasibility of a 12-week progressive resistance training program for people with patellofemoral pain (PFP) targeting proximal muscle strength and power; and resulting clinical and muscle capacity outcomes. Design: Feasibility study. Setting: Clinical environment. Participants: Mixed-sex sample of people with PFP. Main outcome measures: Feasibility outcomes included eligibility, recruitment rate, intervention adherence, and drop-outs. Secondary outcomes included perceived recovery, physical function (AKPS and KOOS-PF), worst pain (VAS-cm), kinesiophobia (Tampa), physical activity (IPAQ), and hip strength (isometric and 10 repetition maximum) and power. Results: Eleven people, from 36 who responded to advertisements, commenced the program. One participant withdrew. Ten participants who completed the program reported improvement (3 completely recovered; 6 marked; and 1 moderate). Higher AKPS (effect size [ES] = 1.81), improved KOOS-PF (ES = 1.37), and reduced pain (ES = 3.36) occurred alongside increased hip abduction and extension dynamic strength (ES = 2.22 and 1.92, respectively) and power (ES = 0.78 and 0.77, respectively). Isometric strength improved for hip abduction (ES = 0.99), but not hip extension. Conclusion: A 12-week progressive resistance training program targeting proximal muscle strength and power is feasible and associated with moderate-large improvements in pain, function, and hip muscle capacity in people with PFP. Further research evaluating the efficacy of progressive resistance training is warranted.
... sufficiently long enough period of exercise; this limitation seems somewhat mitigated because changes over the 12 weeks in the exercise group in our study was comparable to those in studies of longer duration exercise. 16 Sixth, based on previous evidence, 34 it is possible there was a subgroup of those with PFP who did not have hip muscle weakness, or foot mobility issues, but were allocated to hip exercises or foot orthoses, respectively. This would only be a valid concern if the notion that hip muscle weakness or mobility are treatment effect modifiers, the latter we showed not to be the case. ...
Article
Objectives To test (i) if greater foot pronation (measured as midfoot width mobility) is associated with better outcomes with foot orthoses treatment, compared with hip exercises and (ii) if hip exercises are superior to foot orthoses, irrespective of midfoot width mobility. Methods A two-arm parallel, randomised superiority clinical trial was conducted in Australia and Denmark. Participants (18–40 years) were included who reported an insidious onset of knee pain (≥6 weeks duration); ≥3/10 numerical pain rating, that was aggravated by activities (eg, stairs, squatting, running). Participants were stratified by midfoot width mobility ( high ≥11 mm change in midfoot width) and site, randomised to foot orthoses or hip exercises and blinded to objectives and stratification. Success was defined a priori as much better or better on a patient-perceived 7-point scale at 12 weeks. Results Of 218 stratified and randomised participants, 192 completed 12-week follow-up. This study found no difference in success rates between foot orthoses versus hip exercises in those with high (6/21 vs 9/20; 29% vs 45%, respectively) or low (42/79 vs 37/72; 53% vs 51%) midfoot width mobility. There was no association between midfoot width mobility and treatment outcome (Interaction effect p=0.19). This study found no difference in success rate between foot orthoses versus hip exercises (48/100 vs 46/92; 48% vs 50%). Conclusion Midfoot width mobility should not be used to help clinicians decide which patient with patellofemoral pain might benefit most from foot orthoses. Clinicians and patients may consider either foot orthoses or hip exercises in managing patellofemoral pain. Trial registration number ACTRN12614000260628.
... However, some studies have demonstrated clinical improvements in both individuals who gained muscle strength and those who did not, when comparing strengthening exercises and education with regards to the clinical outcomes of pain and symptoms; moreover, despite the increase in strength in the group submitted to strengthening exercises, no differences between groups were found with regards to pain and functioning (Esculier et al., 2017;Hott et al., 2019b). This may be explained by the fact that not all individuals affected by PFP exhibit a lower production of muscle strength (Callaghan, 2018;Selfe et al., 2016) as shown in our results, and exercise has other benefits besides the gain in strength, such as increase the capacity of the tissue to sustain the mechanical load and the de-sensitization of the central nervous system (Esculier et al., 2017;Rabelo and Lucareli, 2018). ...
Article
Background Patellofemoral pain has a poor long-term prognosis, which can be explained by a pain sensitization process. The pain sensitization process may be related to the increase of stress in the patellofemoral joint that is already associated with kinematic alterations and weakness in the musculature of the hip and knee. Methods Were compared the pressure pain threshold, temporal summation, conditioned pain modulation, angular kinematics, and muscle strength between 26 patellofemoral pain and 24 asymptomatic women and then correlated pain sensitization variables with biomechanical variables in pain group. The pressure pain threshold was determined on seven points of the knee, tibialis anterior muscle, and elbow. Ten consecutive stimuli were performed for temporal summation, and cold water was used as the conditioning stimulus for conditioned pain modulation. The strength of hip and knee muscles was determined using a manual dynamometer. Three-dimensional kinematics were evaluated during the lateral step down, considering peak and excursion values of the movement and the Movement Deviation Profile. Findings The pressure pain threshold of the elbow (2.13 [1.84–2.41] vs. 1.63 [1.25–2] kg/cm²), all sites of the knee were lower, as well as the Movement Deviation Profile was higher (9.33 [9.20–9.46] vs. 12.43 [12.1–12.75]) in the pain group. No difference in temporal summation, conditioned pain modulation, muscle strength and discrete kinematic values were found. No significant correlation was found between the Movement Deviation Profile and pressure pain threshold. Interpretation Biomechanical factors, pain processing, and modulation in women with patellofemoral pain, when different from asymptomatic individuals, are not necessarily associated.
... 28 A challenge with the management of PFP is its multifactorial nature and the need for identifying treatment classifications for this patient population. 19,35 While therapeutic exercise remains the recommended treatment strategy, 36 the addition of patella taping can provide short-term benefit for individuals with PFP 36 and PFJOA. 37 This investigation supports the use of US to identify females with PFP and excessive patella lateralization. ...
Article
Background: Evidence suggests that individuals with patellofemoral pain (PFP) may develop patellofemoral joint osteoarthritis (PFJOA). Limited data exist regarding an absolute association between PFP and PFJOA. Understanding this relationship will support the need for early interventions to manage PFP. Hypothesis/purpose: This study was conducted to determine if females with PFP have a patella position and cartilage biomarkers similar to individuals with PFJOA. It was hypothesized that females with PFP and excessive patella lateralization would have higher cartilage biomarker levels than controls. It also was hypothesized that a significant association would exist between pain and cartilage biomarker levels in subjects with excessive patella lateralization. Study design: Single-occasion, cross-sectional, observational. Methods: Pain was assessed using a 10-cm visual analog scale (VAS) for activity pain over the previous week. Patella offset position (RAB angle) was measured using diagnostic ultrasound. Urine was collected and cartilage biomarkers quantified by analyzing C-telopeptide fragments of type II collagen (uCTX-II). Independent t-tests were used to determine between-group differences for RAB angle and uCTX-II. Bivariate correlations were used to determine associations between VAS and uCTX-II for females with PFP. Results: Subjects (age range 20 to 30 years) had similar RAB angles (p = 0.21) and uCTX-II (p = 0.91). A significant association only existed between VAS scores and uCTX-II for females with PFP who had a RAB angle > 13 ° (r = 0.86; p = 0.003). Comparison of uCTX-II in the 25-to-30-year-old females with PFP and excessive patella lateralization in the current study to published normative data showed that this cohort had elevated biomarkers. Conclusion: These findings support that a certain cohort of individuals with PFP have features similar to individuals with confirmed PFJOA (patella lateralization and elevated biomarkers). Additional studies are needed to determine if interventions can reverse not only pain but biomarker levels. Level of evidence: 2b (diagnosis).
... Interestingly, this does not appear to be a function of PFP duration, or whether PFP is bilateral or unilateral. Although PFP subgroups have been investigated in previous studies [16], there is clearly further work to be done to identify PFP phenotypes. ...
Article
Background Sitting-related pain is a common feature of patellofemoral pain (PFP). However, little is known regarding features associated with sitting-related PFP. The aim of this study was to determine whether sitting-related PFP is associated with patellofemoral alignment, morphology and structural magnetic resonance imaging (MRI) features of the patellofemoral joint (cartilage lesions, bone marrow lesions, fat pad synovitis). Methods 133 individuals with PFP were included from two unique but similar cohorts. Participants were classified into one of three groups based on their response to item 8 of the Anterior Knee Pain Scale: (i) problems with sitting; (ii) sitting pain after exercise; and (iii) no difficulty with sitting. All participants underwent 3T Magnetic Resonance Imaging (MRI) to enable: (i) scoring of structural features of the patellofemoral joint with MRI Osteoarthritis Knee Score (MOAKS); and (ii) patellofemoral alignment and morphology measurements using standardised methods. The association of sitting pain to bony alignment, morphology and MOAKS features were evaluated using multinomial logistic regression (adjusted for age, sex, BMI; reference group = no difficulty with sitting). Results 82 (61.7%) participants reported problems with sitting, and 24 (18%) participants reported sitting pain after exercise. There were no significant associations between the presence of sitting pain and any morphology, alignment or structural characteristics. Conclusions Findings indicate that PFP related to sitting is not associated with patellofemoral alignment, morphology, or structural MRI features of the patellofemoral joint. Further research to determine mechanisms of sitting-related PFP, and inform targeted treatments, are required.
... In interpreting these results, it should be considered that the exercise programs aimed to isolate the muscle groups in question, as opposed to employing a complex or multimodal exercise-based intervention as is most commonly used in PFP. 6,7,9 Further, isolated exercises might be more effective if targeted to specific deficits, as theorized by Selfe et al 44 These factors might affect relative effectiveness of guided exercise compared to the control group. To our knowledge, this is the first study to use patient education attempting to influence kinesiophobia and self-mastery in PFP, despite the potential importance of these factors. ...
Article
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Objective: Extended follow-up of a randomized trial comparing hip-focused exercise, knee-focused exercise and free physical activity in patellofemoral pain (PFP). Methods: A single-blind randomized controlled trial included 112 patients aged 16-40 years (mean 27.6 years) with a clinical diagnosis of PFP ≥3 months (mean 39 months) and pain ≥3/10 on a Visual Analog Scale. Patients were randomized to a 6-week exercise-based intervention consisting of either isolated hip-focused exercises (n=39), traditional knee-focused exercise (n=37) or free physical activity (n=36). All patients received the same patient education. The primary outcome measure was the Anterior Knee Pain Scale (AKPS, 0-100). Secondary outcomes were usual and worst pain, Tampa Scale of Kinesiophobia, Knee Self-Efficacy Score, Euro-Qol (EQ-5D-5L), step-down test, and isometric strength. Blinded observers assessed outcomes at baseline, three months and 12 months. The study was designed to detect a difference in AKPS >10 at 12 months. Results: After one year there were no significant between-group differences in any primary or secondary outcomes. Between-group differences for AKPS were: Knee versus free physical activity -4.3 (95%CI -12.3 to 3.7); Hip versus free physical activity -1.1 (95%CI -8.9 to 6.7); Hip versus Knee 3.2 (95%CI -4.6 to 11.0). The cohort as a whole improved significantly at 3 months and 12 months compared to baseline for all measures except for knee extension strength. Conclusion: After one year, there was no difference in effectiveness of knee exercise, hip exercise or free physical activity, when combined with patient education in PFP.
... First, the guided exercises in this study were targeted toward isolated muscle groups and not as part of a complex exercise strategy or multimodal intervention, as is often used in PFP. 8,44,56 Second, an isolated exercise regimen might be more effective if it were targeted to specific deficits, as in the subgroup theory by Selfe et al. 49 Third, the content of the educational component, with stress on kinesiophobia, is different from that previously investigated, which might influence its effectiveness. Finally, we note that our cohort has a relatively long pain duration and/or low AKPS score as compared with other studies. ...
Article
Background: Exercise for patellofemoral pain (PFP) is traditionally knee focused, targeting quadriceps muscles. In recent years, hip-focused exercise has gained popularity. Patient education is likely an important factor but is underresearched. Purpose: To compare 3 treatment methods for PFP, each combined with patient education: hip-focused exercise, knee-focused exercise, or free physical activity. Study design: Randomized controlled trial; Level of evidence, 1. Methods: A single-blind randomized controlled trial was performed with 112 patients who were 16 to 40 years old (mean, 27.6 years) and had a symptom duration >3 months (mean, 39 months) with a clinical diagnosis of PFP and no radiograph or magnetic resonance evidence of other pathology. Patients were randomized to a 6-week intervention consisting of patient education combined with isolated hip-focused exercise (n = 39), traditional knee-focused exercise (n = 37), or free physical activity (n = 36). The primary outcome was Anterior Knee Pain Scale (0-100) at 3 months. Secondary outcomes were visual analog scale for pain, Tampa Scale for Kinesiophobia, Knee Self-efficacy Scale, EuroQol, step-down, and isometric strength. Results: There were no between-group differences in any primary or secondary outcomes at 3 months except for hip abduction strength and knee extension strength. Between-group differences at 3 months for Anterior Knee Pain Scale were as follows: knee versus control, 0.2 (95% CI, -5.5 to 6.0); hip versus control, 1.0 (95% CI, -4.6 to 6.6); and hip versus knee, 0.8 (95% CI, -4.8 to 6.4). The whole cohort of patients improved for all outcomes at 3 months except for knee extension strength. Conclusion: The authors found no difference in short-term effectiveness in combining patient education with knee-focused exercise, hip-focused exercise, or free training for patients with PFP. Registration: NCT02114294 (ClinicalTrials.gov identifier).
... Although on visual inspection no differences in responses were observed between foot types, recruitment did not target specific foot types and so most participants had a neutral foot posture. Given the potential importance of sub-groups (Selfe et al., 2016), perhaps the mixed sample of foot postures masked an effect of FOs for a specific foot type, as foot type and medial arch height in particular will influence the contact area of FOs with the foot and may also influence soft tissue size Murley et al., 2014). Our sample size was insufficient to account for the effect of foot posture on foot soft tissue morphology or skin sensitivity. ...
Article
Full-text available
Altering plantar load using foot orthoses (FOs) may alter the mechanical work required of internal structures and change the size of muscle and connective tissues. Skin sensitivity might also change as a result of altering mechanoreceptor stimulation. This study investigated the effects of FOs on foot soft tissue morphology and skin sensitivity over three months of use. Forty-one healthy participants wore prefabricated FOs (n = 23) or no insert (n = 18) for three months. The FOs were prescribed specific to each participant, using criteria of a change in peak pressure of 8% in the medial arch (pressure increase) and medial heel (pressure decrease). Ultrasound images were recorded pre- and post-FOs use to derive cross-sectional area and thickness of: abductor hallucis, flexor hallucis brevis, flexor digitorum brevis and the Achilles tendon at the insertion and mid-portion. Plantar fascia thickness was measured at the insertion and midfoot. The minimal detectable difference was established in piloting (n = 7). Skin sensitivity was measured with monofilaments at the dorsum (between the hallux and second toe), medial and lateral heel, medial and lateral arch and the 1st metatarsal head. The FOs increased peak pressure by 15% in the medial arch and reduced it by 21% in the medial heel. None of the changes in soft tissue measurements was greater than the minimal detectable difference and there were no effects of group and time. Skin sensitivity decreased over time at the 1st metatarsal head for both groups, but there was no group effect. Using FOs over three months did not change the foot tissues nor skin sensitivity. This study challenges the notion that FOs make muscles smaller.
... The ongoing uncertainty regarding the pathogenesis of PFP may relate to the presence of subgroups within the patient population with PFP. Selfe et al. (2016) were the first to describe subgroups of patients with PFP on the basis of six clinical tests. These included 'strong', 'weak and tighter' and 'weak and pronated foot' groups [16]. ...
Article
Patellofemoral pain is one of the most common knee complaints, particularly among physically active young individuals. Although once thought to be self-limiting, prospective studies have demonstrated the propensity towards the chronicity of patellofemoral pain (PFP). The pathogenesis of PFP is complex, with multiple interactive pathways suggested to contribute to its onset and persistence. Quadriceps weakness is one of the few risk factors of PFP, with at least moderate evidence from prospective studies, although limited clinical trials of lower limb strengthening have generally not been successful in preventing PFP. The challenge of managing PFP is reflected by a lack of evidence-based clinical guidelines. International consensus and current evidence recommends exercise therapy, focussed on hip and knee strengthening, as a cornerstone of management to reduce PFP. Rethinking management approaches beyond exercise therapy to incorporate movement retraining, education and psychosocial aspects provides potential avenues to enhance outcomes for patients with PFP.
... These pathologies are very serious since current rehabilitation strategies have poor outcomes. Recent research in PFP shows that risk factors are not only multifactorial but that some combinations tend to occur together, forming different subgroups [2,3]. Rehabilitating subjects in accordance with the main risk factors [4] and subgroups considerably improves the outcomes [5]. ...
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Background: Even though chronic knee pain is common in volleyball, neuromuscular imbalance as a potential risk factor has not been investigated in volleyball-specific tasks. The aim of the study was to compare neuromuscular control between healthy and injured players in a clinical jump test and a volleyball-specific jump task in real field conditions. Methods: Six athletes with knee pain and nine controls were included. Surface electromyographic data were recorded from the mm. vastus medialis (VM) and lateralis (VL) of both legs. VM/VL activation ratio was calculated from countermovement jump (CMJ) and volleyball spike indoors and on two beach surfaces. Results: All subjects had pain in the leading leg. Mann-Whitney U Test (M-W-U Test) revealed a significantly lower VM/VL ratio of the leading leg (always affected) of the injured compared with that of the healthy control group for the CMJ and spike jump on all three grounds. Bland-Altman analysis revealed low bias and low difference in standard deviation for the injured leg but high values for the uninvolved leg and healthy controls between tasks and grounds. These results could indicate that neuromuscular control might not adapt too well to different movement tasks and grounds in the injured leg. Conclusion: Athletes with chronic knee pain might have lower VM/VL ratios than controls independent from movement task and ground. Neuromuscular control in injured athletes might be less adaptable to new circumstances. The results of neuromuscular control in laboratory settings might be applicable to field conditions in injured legs but not healthy ones.
Article
Het patellofemorale pijnsyndroom, ook wel chondromalacie of ‘theaterknie’ genoemd, is een aandoening van de knie, die vooral vrouwelijke adolescenten en jongvolwassenen treft. Oefentherapie onder begeleiding van een fysiotherapeut is bewezen effectief. De pathogenese staat echter nog steeds ter discussie en de prognose van de aandoening is ongunstig. Wat is de optimale behandeling voor deze veelvoorkomende knieklacht?
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Article
Background Excessive pronation has been implicated in patellofemoral pain (PFP) aetiology and foot orthoses are commonly prescribed for PFP patients. Pronation can be assessed using foot posture tests, however, the utility of such tests depends on their association with foot and lower-limb kinematics. Research questions Do PFP participants compared with healthy participants (1) have a more pronated foot measured with static foot tests and a kinematic multi-segmental foot model and (2) is there an association between static foot posture and foot and lower limb kinematics during walking? Methods A case-control study including 22 participants (n = 11 PFP, 5 females per group, aged 24 ± 3 (mean ± SD) years) was conducted. Foot posture measures included Arch Height Ratio, Navicular Drop (ND), and Foot Posture Index. Between-group comparisons of foot posture, segment and joint angle magnitudes, and associations between foot posture and kinematic data during gait were evaluated. Results There were no group differences in foot posture tests and mean joint angles. PFP participants had greater internal rotation of the shank and rearfoot segments, and adduction of the mid- and forefoot in the transverse plane (all p < 0.05). Greater ND was associated with increased forefoot abduction (rho=-0.68, p = 0.02) in healthy participants but no relationships were found between foot posture and kinematics in PFP participants. Significance Foot posture and kinematic data did not indicate excessive pronation in PFP participants questioning the use of orthoses to correct pronation. Larger studies are needed to determine the utility of foot posture tests as indicators of gait abnormalities in PFP.
Article
Aim To evaluate the association between anterior knee pain (AKP) and traditional Indian habits of cross-legged sitting and squatting which involve deep knee flexion. Materials and methods A case control study was carried out in 225 patients and 225 age and sex matched controls at a tertiary care university hospital in South India over 3 years. Males and females between 18 and 55 years were evaluated using a clinical proforma of history and musculoskeletal examination. The details of deep knee flexion habits with quantification of duration were noted and participants were categorized into those who sat and did not sit cross legged, and squatters and nonsquatters. Odds ratios and chi-square tests were calculated for both these categorical variables. A subgroup analysis and stratified analysis were also performed. Results The Odds ratios for cross-legged sitting and squatting were not significant at 0.88 and 0.92 respectively. Sixty-nine point three percentage of the AKP cases and 72% of the controls sat cross legged (p = 0.534) and 67.6% of the AKP cases and 69.3% of controls habitually squatted (p = 0.685). Stratified analysis revealed a protective effect of cross legged sitting in AKP cases with quadriceps muscle tightness. Conclusion This study did not find an association between AKP and Indian habits of deep knee flexion. More than 65% of all the participants regularly engaged in these habits. Laboratory biomechanical analysis of these positions is suggested in future to understand their effect on knee joint. Clinical significance These positions are integral to daily habits of many Indians. The advice to AKP patients to avoid them due to their probable AKP association is not supported by the current study. Clinicians can consider the impact on the patient's quality of life before advising against these positions. How to cite this article Parikh TK, Arumugam S. Are Indian Habits of Cross-legged Sitting and Squatting associated with Anterior Knee Pain? J Postgrad Med Edu Res 2017;51(1):1-6.
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Patellofemoral pain (PFP) is a common musculoskeletal-related condition that is characterized by insidious onset of poorly defined pain, localized to the anterior retropatellar and/or peripatellar region of the knee. The onset of symptoms can be slow or acutely develop with a worsening of pain accompanying lower-limb loading activities (eg, squatting, prolonged sitting, ascending/descending stairs, jumping, or running). Symptoms can restrict participation in physical activity, sports, and work, as well as recur and persist for years. This clinical practice guideline will allow physical therapists and other rehabilitation specialists to stay up to date with evolving PFP knowledge and practices, and help them to make evidence-based treatment decisions. J Orthop Sports Phys Ther. 2019;49(9):CPG1-CPG95. doi:10.2519/jospt.2019.0302.
Article
Background: Unfavorable treatment outcomes for people with patellofemoral pain (PFP) have been attributed to the potential existence of subgroups that respond differently to treatment. Objectives: This study aimed to identify subgroups within PFP by combining modifiable clinical, biomechanical, and imaging features and exploring the prognosis of these subgroups. Methods: This was a longitudinal cohort study, with baseline cluster analyses. Baseline data were analyzed using a 2-stage cluster analysis; 10 features were analyzed within 4 health domains before being combined at the second stage. Prognosis of the subgroups was assessed at 12 months, with subgroup differences reported as global rating of change and analyzed with an exploratory logistic regression adjusted for known confounders. Results: Seventy participants were included (mean age, 31 years; 43 [61%] female). Cluster analysis revealed 4 subgroups: "strong," "pronation and malalignment," "weak," and "active and flexible." Descriptively, compared to the strong subgroup (55% favorable), the odds of a favorable outcome were lower in the weak subgroup (31% favorable; adjusted odds ratio [OR] = 0.30; 95% confidence interval [CI]: 0.07, 1.36) and the pronation and malalignment subgroup (50%; OR = 0.64; 95% CI: 0.11, 3.66), and higher in the active and flexible subgroup (63%; OR = 1.24; 95% CI: 0.20, 7.51). After adjustment, compared to the strong subgroup, differences between some subgroups remained substantive, but none were statistically significant. Conclusion: In this relatively small cohort, 4 PFP subgroups were identified that show potentially different outcomes at 12 months. Further research is required to determine whether a stratified treatment approach using these subgroups would improve outcomes for people with PFP. Level of evidence: Diagnosis, level 2b. J Orthop Sports Phys Ther, Epub 18 Jun 2019. doi:10.2519/jospt.2019.8607.
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Background Patellofemoral pain (PFP) is a prevalent knee condition with many proposed biomechanically orientated etiological factors and treatments. Objective We aimed to systematically review and synthesize the evidence for biomechanical variables (spatiotemporal, kinematic, kinetic) during walking and running in people with PFP compared with pain-free controls, and determine if biomechanical variables contribute to the development of PFP. Design Systematic review and meta-analysis. Data sources We searched Medline, CINAHL, SPORTDiscus, Embase, and Web of Science from inception to October 2021. Eligibility criteria for selecting studies All study designs (prospective, case–control [± interventional component, provided pre-intervention data were reported for both groups], cross-sectional) comparing spatiotemporal, kinematic, and/or kinetic variables during walking and/or running between people with and without PFP. Results We identified 55 studies involving 1300 people with PFP and 1393 pain-free controls. Overall pooled analysis identified that people with PFP had slower gait velocity [moderate evidence, standardized mean difference (SMD) − 0.50, 95% confidence interval (CI) − 0.72, − 0.27], lower cadence (limited evidence, SMD − 0.43, 95% CI − 0.74, − 0.12), and shorter stride length (limited evidence, SMD − 0.46, 95% CI − 0.80, − 0.12). People with PFP also had greater peak contralateral pelvic drop (moderate evidence, SMD − 0.46, 95% CI − 0.90, − 0.03), smaller peak knee flexion angles (moderate evidence, SMD − 0.30, 95% CI − 0.52, − 0.08), and smaller peak knee extension moments (limited evidence, SMD − 0.41, 95% CI − 0.75, − 0.07) compared with controls. Females with PFP had greater peak hip flexion (moderate evidence, SMD 0.83, 95% CI 0.30, 1.36) and rearfoot eversion (limited evidence, SMD 0.59, 95% CI 0.03, 1.14) angles compared to pain-free females. No significant between-group differences were identified for all other biomechanical variables. Data pooling was not possible for prospective studies. Conclusion A limited number of biomechanical differences exist when comparing people with and without PFP, mostly characterized by small-to-moderate effect sizes. People with PFP ambulate slower, with lower cadence and a shortened stride length, greater contralateral pelvic drop, and lower knee flexion angles and knee extension moments. It is unclear whether these features are present prior to PFP onset or occur as pain-compensatory movement strategies given the lack of prospective data. Trial Registration PROSPERO # CRD42019080241.
Article
Objective: To determine whether gluteus medius muscle thickness or activation differed between left and right sides, and were associated with patellofemoral pain presence or severity. Design: Males and females were recruited and screened by a physiotherapist for inclusion in the control or PFPS group. Bilateral measures were obtained for Q angle, and gluteus medius muscle thickness at rest and on contraction via standing hip external rotation, using ultrasound. Muscle activation was calculated as the percentage change in muscle thickness on contraction relative to at rest. PFPS participants completed the Anterior Knee Pain Scale and a visual analogue pain scale. Results: Gluteus medius muscle thickness at rest and on contraction, muscle activation, and Q angle were not different between control (n=27; 63% female) and PFPS (n=27; 59% female) groups. However, PFPS participants had a significantly larger left-right side imbalance in gluteus medius muscle activation than controls (15.9±19.3% versus 4.4±21.9%; p< 0.05). Among PFPS participants, the magnitude of asymmetry of gluteus medius muscle activation was correlated with knee pain score (r=0.425, p=0.027). Conclusion: Asymmetry of gluteus medius muscle activation was associated with PFPS and pain severity. This is clinically relevant for PFPS prevention and treatment, particularly since this was quantifiable using ultrasound.
Article
Background The Targeted Interventions for Patellofemoral Pain studies (TIPPs) have identified three subgroups exist in UK and Turkish patellofemoral pain (PFP) populations: Strong; Weak and Tight; and Weak and Pronated, based on six clinical assessments. The thresholds used to develop the subgrouping algorithms were based on normative values sourced from various populations and countries. Objectives Explore normative scores from the clinical assessments in a singular non-PFP population whilst considering potential differences between ethnicities and sex (primary aim). Revisit inter-rater reliability of each assessment (secondary aim). Design Cross-sectional and test-retest. Method The six assessments; rectus femoris length, gastrocnemius length, patellar mobility, hip abductor strength, quadriceps strength, and Foot Posture index (FPI) were measured in 89 New Zealanders (34% Māori, 45% female). Two raters independently assessed 17 participants to examine inter-rater reliability. Results Significant interactions between ethnic group and sex were noted for rectus femoris length and patella mobility. Māori versus European males exhibited greater rectus femoris tightness (p = 0.001). Māori versus European females demonstrated greater patellar mobility (p = 0.002). Females were significantly weaker than males in normalised strength measures (p < 0.001), and had lower FPIs. Mean differences between testers for all measures were small and not significant, except for FPI which had a 2.0 point median difference (p = 0.021). Conclusions Our results indicate that sex is an important factor worth considering within the TIPPs subgrouping approach, more than ethnicity, especially for the normalised strength measures. The sub-optimal reliability of FPI warrant reconsideration of its inclusion within TIPPs.
Article
Objective: To determine the effects of non-surgical treatments on pain and function in people with patellofemoral pain (PFP). Design: Systematic review with meta-analysis. Literature search: We searched Medline, Web of Science, and Scopus to May 2022 for interventional randomised controlled trials (RCTs) in people with PFP. Study selection criteria: We included RCTs that were scored >7 on the PEDro scale. Data synthesis: We extracted homogenous pain and function data at short- (<3 months), medium- (>3 to <12 months) and long-term (>12 months) follow up. Interventions demonstrated primary efficacy if outcomes were superior to sham, placebo, or wait-and-see control. Interventions demonstrated secondary efficacy if outcomes were superior to an intervention with primary efficacy. Results: We included 65 RCTs. Four interventions demonstrated short-term primary efficacy: knee-targeted exercise therapy for pain (SMD 1.16, 95% CI 0.66, 1.66) and function (SMD 1.19, 95% CI 0.51, 1.88), combined interventions for pain (SMD 0.79, 95% CI 0.26, 1.29) and function (SMD 0.98, 95% CI 0.47, 1.49), foot orthoses for global rating of change (OR 4.31, 95% CI 1.48, 12.56), and lower-quadrant manual therapy for pain (SMD 2.30, 95% CI 1.60, 3.00). Two interventions demonstrated short-term secondary efficacy compared to knee-targeted exercise therapy: hip-and-knee-targeted exercise therapy for pain (SMD 1.02, 95% CI 0.58,1.46) and function (SMD 1.03, 95% CI 0.61, 1.45), and knee-targeted exercise therapy and perineural dextrose injection for pain (SMD 1.34, 95% CI 0.72, 1.95) and function (SMD 1.21, 95% CI 0.60, 1.82). Conclusion: Six interventions had positive effects at three-months for people with PFP, with no intervention adequately tested beyond this timepoint.
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PURPOSE: This study aimed to explore the efficacy of U.S. Montmorency tart cherry in treating recreationally active individuals with patellofemoral pain. METHODS: Twenty-four recreationally active participants with patellofemoral pain were randomly separated into either placebo (males N = 8, females N = 4, age = 43.30 ± 7.86 yrs, mass = 72.10 ± 17.89 kg, stature = 171.16 ± 10.17, BMI = 24.31 ± 3.75 kg/m 2 , symptom duration = 30.18 ± 10.90) or Montmorency tart cherry (males N = 9, females N = 3, age = 41.75 ± 7.52 yrs, mass = 76.96 ± 16.64 kg, stature = 173.05 ± 7.63, BMI = 25.53 ± 4.03 kg/m 2 , symptom duration = 29.73 ± 11.88) groups. Both groups ingested 60 mL of either Montmorency tart cherry concentrate or taste matched placebo daily for 6-weeks. Measures of self-reported pain (KOOS PF), psychological wellbeing (COOP WONCA) and sleep quality (PSQI) alongside blood biomarkers (Creactive protein, uric acid, TNF alpha, creatinine and total antioxidant capacity) and knee biomechanics were quantified at baseline and 6-weeks. Differences between groups were examined using linear mixed effects models. RESULTS: There was 1 withdrawal in the cherry and 0 in the placebo group and no adverse events were noted in either condition. The placebo condition exhibited significant improvements (baseline = 67.90±16.18 & 6-weeks = 78.04±14.83) in KOOS PF scores compared to the tart cherry group (baseline = 67.28±12.55& 6-weeks = 67.55±20.61). No other statistically significant observations were observed. CONCLUSION: Tart cherry supplementation as specifically ingested in the current investigation, does not appear to be effective in mediating improvements in patellofemoral pain symptoms in recreationally active individuals.
Article
Background Although Movement System Impairment (MSI) model classifies patients with knee impairments, it has some limitations. This study compares MSI model with a new Partitioning Around Medoids (PAM) model in knee pain patients. Methods In this cross-sectional study, knee movement impairments (signs) and symptoms. (pain) of 200 patients were studied in eight different functional positions. After modification of impairments, the examinations were repeated to record the changes in symptoms. The patients were then classified based on the signs and symptoms firstly by MSI model and secondly using PAM clustering by R software. Results PAM model has a similar acceptable grouping compared to MSI because most patients are in 4 similar categories in both methods: valgus, varus, hyperextension and hypomobility. However, due to low discriminative power of the tests used for finding hypermobility and patellar dysfunctions, these sub-clusters are absent in PAM model. Instead, two new sub-clusters of self-management and valgus with hypomobility were found. Most importantly, the PAM model sorted the signs and symptoms based on their discriminative power and eliminated trivial tests so that the therapist can classify patients more quickly by performing clinically relevant tests. Conclusion The new PAM method can be advantageous for therapists since it defines the importance of signs over symptoms in examination, prioritizes examination tests, and outlines tests with lower discriminative power. In PAM model, patients in the hypermobility and patellar subgroups of MSI model merged into other sub-clusters due to low discriminating power of their characteristics.
Article
Due to the multifactorial nature of patellofemoral pain, it is often difficult to identify an individual patient’s exact cause of pain. Understanding how demographic variability influences these various factors will support improved consensus in regards to the etiology of PF pain. Thus, in this retrospective study, we tested the hypothesis that sex, height, weight, body mass index (BMI), and age influence the determination of between-groups differences in PF kinematics. We included 41 skeletally mature patients with patellofemoral pain and 79 healthy controls. Three-dimensional patellofemoral kinematics were quantified from dynamic magnet resonance images. We ran multiple regression analyses to determine the influence of demographic covariates (age, sex, height, weight, and BMI) on patellofemoral kinematics. Patellar shift was significantly influenced by weight (p=0.009) and BMI (p=0.009). Patellar flexion was influenced by height (p=0.020) and weight (p=0.040). Patellar tilt and superior displacement were not influence by demographic variables. Age and sex did not influence kinematics. This study supports the hypothesis that demographic parameters influence PF kinematics. The fact that weight, a modifiable measure, influences both patellar shift and flexion has strong implications for future research and clinical interventions. Clinically, weight loss may have a dual benefit of reducing joint stress and maltracking in patients who are overweight and experiencing patellofemoral pain. The influence of key demographics on patellofemoral kinematics, reinforces the clear need to control for population characteristics in future studies. As such, going forward, improved demographic matching between control and patient cohorts or more advanced statistical techniques that compensate for confounding variables are necessary.
Article
The aim of this experiment was to provide insight into the immediate influence of both semi-custom insoles and knee sleeves in recreational male runners/athletes suffering from patellofemoral pain and also to explore the association between the extent of patellofemoral pain and psychological wellbeing. Experiment 1 examined 17 male recreational runners with patellofemoral pain, in semi-custom insole and no-insole conditions. Experiment 2 examined 13 male recreational athletes with patellofemoral pain, undertaking run, [Formula: see text] cut and single-leg hop movements in knee sleeve and no-sleeve conditions. In both experiments, motion capture and ground reaction forces were collected, allowing kinetics and three-dimensional kinematics to be calculated alongside patellofemoral joint loading quantified using musculoskeletal modeling. In both experiments, patellofemoral pain symptoms were examined using the KOOS patellofemoral pain subscale and psychological wellbeing using the COOP-WONCA questionnaire. The findings from both experiments showed that pain symptoms significantly predicted psychological wellbeing ([Formula: see text] in experiment 1 and [Formula: see text] in experiment 2). Experiment 1 showed that orthoses significantly reduced tibial internal rotation range of motion (no-[Formula: see text] and [Formula: see text]) whilst also increasing the peak knee adduction moment (no-[Formula: see text][Formula: see text]N[Formula: see text]m/kg and [Formula: see text][Formula: see text]N[Formula: see text]m/kg). The findings from experiment 2 revealed that the knee sleeve reduced the peak patellofemoral force (no-[Formula: see text][Formula: see text]BW and [Formula: see text][Formula: see text]BW) in the run movement and the patellofemoral load rate in the cut movement (no-[Formula: see text][Formula: see text]BW/s and [Formula: see text][Formula: see text]BW/s). Overall, the findings confirm that pain symptoms are predictive of psychological wellbeing in recreational male athletes with patellofemoral pain. Furthermore, the findings suggest that both insoles and knee sleeves may provide immediate biomechanical benefits in recreationally active individuals with patellofemoral pain, although when wearing insoles this may be at the expense of an increased knee adduction moment during running.
Article
Objectives Guidelines for a comprehensive rehabilitation programme for patellofemoral pain (PFP) have been developed by international experts. The aim of this study was to analyse the effect of such a rehabilitative exercise programme on pain, function, kinesiophobia, running biomechanics, quadriceps strength and quadriceps muscle inhibition in individuals with PFP. Design Observational study. Setting Clinical environment. Participants Twenty-seven participants with PFP. Main outcome measures Symptoms [numeric pain rating scale (NPRS)and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score (KOOS)], function measured by using the KUJALA scale and KOOS, kinesiophobia measured by using the Tampa scale, three-dimensional biomechanical running data, quadriceps isometric, concentric and eccentric strength and arthrogenic muscle inhibition (AMI) were acquired before and after the six-week exercise programme. Results Although pain did not significantly improve all patients were pain-free after the six-week exercise programme (NPRS: p = 0.074). Function, kinesiophobia and quadriceps AMI improved significantly after the six-week exercise programme (KUJALA: p = 0.001, KOOS: p = 0.0001, Tampa: p = 0.017, AMI: p = 0.018). Running biomechanics during stance phase did not change after the exercise intervention. Quadriceps strength was not different after the six-week exercise programme (isometric: p = 0.992, concentric: p = 0.075, eccentric: p = 0.351). Conclusion The results of this study demonstrate that the current exercise recommendations can improve function and kinesiophobia and reduce pain and AMI in individuals with PFP. There is a need for reconsideration of the current exercise guidelines in stronger individuals with PFP.
Article
Background: The movement system impairment (MSI) model is a clinical model that can be used for the classification, diagnosis, and treatment of knee impairments. By using the partitioning around medoids (PAM) clustering method, patients can be easily clustered in homogeneous groups through the determination of the most discriminative variables. The present study aimed to reduce the number of clinical examination variables, determine the important variables, and simplify the MSI model using the PAM clustering method. Methods: The present cross-sectional study was performed in Shiraz, Iran, during February-December 2018. A total of 209 patients with knee pain were recruited. Patients' knee, femoral and tibial movement impairments, and the perceived pain level were examined in quiet standing, sitting, walking, partial squatting, single-leg stance (both sides), sit-to-stand transfer, and stair ambulation. The tests were repeated after correction for impairments. Both the pain pattern and the types of impairment were subsequently used in the PAM clustering analysis. Results: PAM clustering analysis categorized the patients in two main clusters (valgus and non-valgus) based on the presence or absence of valgus impairment. Secondary analysis of the valgus cluster identified two sub-clusters based on the presence of hypomobility. Analysis of the non-valgus cluster showed four sub-clusters with different characteristics. PAM clustering organized important variables in each analysis and showed that only 23 out of the 41 variables were essential in the sub-clustering of patients with knee pain. Conclusion: A new direct knee examination method is introduced for the organization of important discriminative tests, which requires fewer clinical examination variables.
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Introduction Patellofemoral pain (PFP) is a common and often long-standing musculoskeletal condition. Evidence of the effectiveness of interventions addressing soft tissue flexibility is conflicting and of inconsistent scientific quality. However, reduced soft tissue flexibility can negatively affect patellofemoral joint kinematics. Lower limb range of motion (LLROM) reflects soft tissue flexibility throughout the kinetic chain. The aim was to evaluate the short-term effectiveness of an intervention targeting LLROM on pain and disability in patients with PFP. Methods A randomized, non-concurrent, multiple-baseline single-case design with a two-week intervention phase and baseline and postintervention phase with varying length was conducted. Eight participants (5 females, 3 males) of age 19(±1.6) years, weekly sports participation 12(±3.1) hours and 17(±14) months symptom duration were included. The Anterior Knee Pain Scale – Dutch Version (AKPS-DV) and the Patient Specific Complaint Scale (PSCS) were administered twice a week. After allocating participants to one of four subgroups of reduced LLROM the intervention was applied. The intervention consisted of soft tissue techniques (mobilization, taping, and stretching). Results Participant 3 and 6 showed a medium and small but statistically significant positive effect on the AKPS-DV. Participant 2 showed a large and statistically significant positive effect on the PSCS. Conclusions This study provides moderate evidence that an intervention targeting LLROM in patients with PFP reduces pain and disability in the short-term. Further research is needed to evaluate the long-term effectiveness and optimize individual treatment outcomes.
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Hinter der Manuellen Therapie stehen seit jeher zahlreiche philosophische Ansätze. Heute nimmt man an, dass sie insbesondere bei schmerzadaptiven Patienten wirkt, die das eigene Schmerzempfinden selbst modulieren können. Der Artikel erörtert die Evidenz in Bezug auf Manuelle Therapie und liefert theoretische Begründungen für die Veränderungen, die man im klinischen Umfeld bei Patienten beobachtet.
Article
Objectives to investigate the distribution of patella skin temperature (Tsk) measurements and to explore the presence of temperature subgroups in patellofemoral pain (PFP) patients. Design cross-sectional observational study design Participants One dataset of 58 healthy participants and 232 PFP patients from three different datasets. Main outcome measures Patella skin temperature, measured by physiotherapists using a low cost hand held digital thermometer. The distribution of patella skin temperature was assessed and compared across datasets. To objectively determine the clinically meaningful number of subgroups, we used the average silhouette method. Finite mixture models were then used to examine the presence of PFP temperature subgroups. Receiver operating characteristic curves were used to estimate optimal patella Tsk thresholds for allocation of participants into the identified subgroups. Results In contrast to healthy participants, the patella skin temperature had an obvious bimodal distribution with wide dispersion present across all three PFP datasets. The fitted finite mixture model suggested three temperature subgroups (cold, normal and hot) that had been recommended by the average silhouette method with discrimination cut-off thresholds for subgroup membership based on receiver operating curve analysis of Cold = < 30.0oC; Normal 30.0-35.2oC; Hot ≥35.2oC. Conclusion A low cost hand held digital thermometer appears to be a useful clinical tool to identify three PFP temperature subgroups. Further research is recommended to deepen understanding of these clinical findings and to explore the implications to different treatments.
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Exercise therapy has been reported as an effective treatment method for patellofemoral pain syndrome (PFPS). However, there is a lack of studies regarding the effectiveness of balance exercise in the treatment of patients with PFPS. This study aimed to prospectively compare changes in proprioception, neuromuscular control, knee muscle strength, and patient-reported outcomes between patients with PFPS treated with knee alignment-oriented static balance exercise (SBE) and dynamic balance exercise (DBE). The participants were divided into 2 groups: 17 knee alignment-oriented SBE group and 19 knee alignment-oriented DBE group. Proprioception was assessed by dynamic postural stability using postural stabilometry. Neuromuscular control and knee muscle strength were measured for acceleration time and peak torque in quadriceps muscle using an isokinetic device. Patient-reported outcomes were evaluated using a visual analog scale for pain and the Kujala Anterior Knee Pain Scale. There was greater improvement in dynamic postural stability (0.9 ± 0.3 vs 1.2 ± 0.5; 95% confidence interval [CI]: 0, 0.6; Effect size: 0.72; P = .021) and quadriceps AT (40.5 ± 14.3 vs 54.1 ± 16.9; 95% CI: 2.9, 24.2; Effect size: 0.86; P = .014) in the DBE group compared to the SBE group. Knee alignment-oriented DBE can be more effective in improving dynamic postural stability and quadriceps muscle reaction time compared with the knee alignment-oriented SBE in PFPS patients with dynamic knee valgus.
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Hintergrund: Überlastungsschmerzen am Knie sind eine sehr häufige Verletzung von Laufsportlern. Die Ursachen dafür können sehr vielfältig sein und sind noch nicht restlos gesichert. Deshalb ist es schwer eine Standardbehandlung festzulegen. Bei den bisherigen Therapieansätzen gibt es noch keine vollständig befriedigende Ergebnisse. Ziel: Die Frage ist, ob der ganzheitliche Ansatz, der in der Osteopathie angewendet wird, gerade durch die vielfältigen möglichen Ursachen nicht einen besseren Behandlungsansatz als ein reines Trainingsprogramm bieten könnte. Material und Methoden: In zwei per Briefwahl zufällig gestalteten Gruppen wurde das selbe standardisierte Trainingsprogramm absolviert. Die Behandlungsgruppe A hat zusätzlich drei osteopathische Behandlungen über einen Zeitraum von 4 Wochen erhalten. Die Beschwerden wurden anhand zweier visuell analogen Schmerzskalen, VaS-U für den durchschnittlichen- und VaS-W für den stärksten Schmerz gemessen. Ergebnis: Sowohl in der Behandlungsgruppe als auch in der Kontrollgruppe konnte eine signifikante Verbesserung erzielt werden. Betreffend des stärksten Schmerzes (VaS-W) war außerdem die Verbesserung in der Behandlungsgruppe signifikant höher als in der Kontrollgruppe (p= 0,027). Beim durchschnittlich empfundenen Schmerz (VaS-U) war die Verbesserung in der Behandlungsgruppe zwar größer, aber der Unterschied nicht signifikant. Schlussfolgerung: Es zeigt sich, dass Osteopathie ein interessanter Behandlungsansatz für Überlastungsschmerzen am Knie bei Laufsportlern sein könnte. Weitere Untersuchungen zum Langzeiteffekt oder prospektive Studien wären interessant Schlüsselbegriffe: Osteopathie, Knieschmerz, Überlastung, Laufsport, VaS
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Patellofemoral pain (PFP) is often seen in physically active individuals and may account for 25-40% of all knee problems seen in a sports injury clinic.1 ,2 Patellofemoral-related problems occur more frequently in women than in men.3 PFP is characterised by diffuse pain over the anterior aspect of the knee and aggravated by activities that increase patellofemoral joint (PFJ) compressive forces, such as squatting, ascending and descending stairs and prolonged sitting, as well as repetitive activities such as running. It, therefore, has a debilitating effect on sufferers’ daily lives by reducing their ability to perform sporting and work-related activities pain free. Dye has described PFP as an orthopaedic enigma, and it is one of the most challenging pathologies to manage.4 Alarmingly, a high number of individuals with PFP have recurrent or chronic pain.5 While physiotherapy interventions for PFP have proven effective compared with sham treatments, treatment results can be disappointing in a proportion of patients. This variability in treatment results may be due to the fact that the underlying factors that contribute to the development of PFP are not being addressed, or are not the same for all patients with PFP. The mission of the 3rd International Patellofemoral Research Retreat was to improve our understanding concerning the factors that contribute to the development and consequently to the treatment of PFP. The 3rd International Patellofemoral Research Retreat was held in Vancouver, Canada, in September 2013, for 3 days: from 18 September to 21 September. After peer-review for scientific merit and relevance to the retreat, 58 abstracts were accepted for the retreat (39 podiums, 8 posters and 11 thematic posters). The podium and poster presentations were grouped into three categories: (1) natural history of PFP and local factors that influence PFP, (2) trunk and distal factors that influence PFP and …
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Patellofemoral pain (PFP) can cause significant pain leading to limitations in societal participation and physical activity. An international expert group has highlighted the need for a classification system to allow targeted intervention for patients with PFP; we have developed a work programme systematically investigating this. We have proposed six potential subgroups: hip abductor weakness, quadriceps weakness, patellar hypermobility, patellar hypomobility, pronated foot posture and lower limb biarticular muscle tightness. We could not uncover any evidence of the relative frequency with which patients with PFP fell into these subgroups or whether these subgroups were mutually exclusive. The aim of this study is to provide information on the clinical utility of our classification system. 150 participants will be recruited over 18 months in four National Health Services (NHS) physiotherapy departments in England. Inclusion criteria: adults 18-40 years with PFP for longer than 3 months, PFP in at least two predesignated functional activities and PFP elicited by clinical examination. Exclusion criteria: prior or forthcoming lower limb surgery; comorbid illness or health condition; and lower limb training or pregnancy. We will record medical history, demographic details, pain, quality of life, psychomotor movement awareness and knee temperature. We will assess hip abductor and quadriceps weakness, patellar hypermobility and hypomobility, foot posture and lower limb biarticular muscle tightness. The primary analytic approach will be descriptive. We shall present numbers and percentages of participants who meet the criteria for membership of (1) each of the subgroups, (2) none of the subgroups and (3) multiple subgroups. Exact (binomial) 95% CIs for these percentages will also be presented. This study has been approved by National Research Ethics Service (NRES) Committee North West-Greater Manchester North (11/NW/0814) and University of Central Lancashire (UCLan) Built, Sport, Health (BuSH) Ethics Committee (BuSH 025). An abstract has been accepted for the third International Patellofemoral Pain Research Retreat, Vancouver, September 2013.
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Purpose To evaluate the prevalence and participation of catastrophizing and fear to movement beliefs on present pain and disability in anterior knee pain patients. Methods A cross-sectional study on 97 patients with chronic anterior knee pain was performed in a secondary healthcare setting. Pain was measured with Visual Analogue Scale and disability with Lysholm Scale. The psychological variables anxiety, depression, pain coping strategies, catastrophizing and fear to movement beliefs were studied by using auto-administered questionnaires. Results Patients showed a high incidence of psychological distress (anxiety and depression), kinesiophobia and catastrophizing. A moderate correlation between pain and disability was found. Among all the coping strategies, only catastrophizing correlated with pain and disability. Anxiety depression and kinesiophobia also correlated with present pain and disability. In the regression model, catastrophizing and depression explained 56 % of the variance of disability and catastrophizing alone explained 37 % of present pain. Conclusion The moderate correlation between pain and disability suggests that pain per se is not able to explain all the variability of disability. Catastrophizing and kinesiophobia are shown to be predictors of present pain and disability in anterior knee pain patients. These findings support the fear avoidance model in the genesis and persistence of pain and disability in anterior knee pain patients and open the door to a biopsychosocial perspective in the management of these patients. Level of evidence III.
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Context: Physicians and clinicians need portable, efficient, and cost-effective assessment tools to determine the effectiveness of rehabilitation programs after knee injury. Progress in rehabilitation should be evaluated using valid and reliable measurement methods. Objective: To examine the test-retest reliability of portable fixed dynamometry (PFD), handheld dynamometry (HHD), and isokinetic dynamometry (IKD). In addition, the authors sought to examine the validity of PFD and HHD by comparing differences in peak torque of the knee flexors and extensors to that of the "gold standard" IKD. Design: Repeated measures. Participants: 16 healthy subjects (age 29.3 ± 7.2 y, height 167.4 ± 8.04 cm, mass 73.7 ± 20.0 kg). Main outcome measures: The dependent variables were peak torque (normalized to body weight) of the knee flexors and extensors; the independent variables were trial (trial 1, trial 2) and instrument (IKD, PFD, and HHD). Results: Test-retest reliability was high for both PFD and IKD. However, fair to poor reliability was found for HHD. There were no differences in peak torque (Nm) between IKD and PFD. However, significant differences in peak torque were observed between IKD and HHD and between PFD and HHD. Conclusions: PFD provides reliable measures of strength and also demonstrates similar output measures as IKD. Its portability, ease of use, and cost provide clinicians an effective means of measuring strength.
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Patellofemoral pain (PFP) is one of the most common lower extremity conditions seen in orthopaedic practice. The mission of the second International Patellofemoral Pain Research Retreat was to bring together scientists and clinicians from around the world who are conducting research aimed at understanding the factors that contribute to the development and, consequently, the treatment of PFP. The format of the 2.5-day retreat included 2 keynote presentations, interspersed with 6 podium and 4 poster sessions. An important element of the retreat was the development of consensus statements that summarized the state of the research in each of the 4 presentation categories. In this supplement, you will find the consensus documents from the meeting, as well as the keynote addresses, schedule, and platform and poster presentation abstracts.
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To investigate the diagnostic accuracy and association to disability of selected functional findings or physical examination tests for patellofemoral pain syndrome (PFPS) in patients with anterior knee pain. A sample of 76 consecutive patients with anterior knee pain was further subdivided into PFPS and other diagnoses. Routine physical examination tests were examined in a prospective, consecutive-subjects design for a cohort of patients with anterior knee pain. Diagnostic accuracy findings, including sensitivity, specificity, positive (PPV) and negative (NPV) predictive value, and positive (LR+) and negative (LR-) likelihood ratios, were calculated for each test. PPV and NPV reflect the percentage of time of positive or a negative test (respectively) accurately captures the diagnosis of the condition. LR+ and LR- reflect alterations in post-test probability when the test is positive or negative (respectively). Lastly, associations to disability (International Knee Documentation Committee (IKDC) subjective form) were calculated for each clinical finding. Diagnostic accuracy analyses of individual functional assessment and situational phenomena suggest that the strongest diagnostic test is pain encountered during resisted muscle contraction of the knee (PPV=82%; LR+=2.2; 95% CI: 0.99-5.2). Clusters of test findings were substantially more diagnostic, with any two of three positive findings of muscle contraction, pain during squatting, and pain during palpation yielding the following values: PPV=89%; LR+=4.0 (95% CI: 1.8-10.3). No individual or clustered test findings were significantly associated with the IKDC score. Combinations of functional assessment tests and situational phenomena are diagnostic for PFPS and may serve to rule in and rule out the presence of PFPS. Single findings are not related to disability scores (IKDC).
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Patellofemoral osteoarthritis (PFOA) is a common form of knee OA in middle and older age, but its relation to PF disorders and symptoms earlier in life is unclear. Our aim was to conduct a systematic review to investigate the strength of evidence for an association between anterior knee pain (AKP) in younger adults and subsequent PFOA. The search strategy included electronic databases (Pubmed, EMBASE, AMED, CINAHL, Cochrane, PEDro, SportDiscus: inception to December 2009), reference lists of potentially eligible studies and selected reviews. Full text articles in any language, - identified via English titles and abstracts, were included if they were retrospective or prospective in design and contained quantitative data regarding structural changes indicative of PFOA, incident to original idiopathic AKP. Eligibility criteria were applied to titles, abstracts and full-texts by two independent reviewers. Data extraction included study location, design, date, sampling procedure, sample characteristics, AKP/PFOA definitions, follow-up duration and rate, and main findings. Foreign language articles were translated into English prior to examination. Seven articles satisfied eligibility (5 English, 2 German). Only one case-control study directly investigated a link between PFOA and prior AKP, providing level 3b evidence in favour of an association (OR 4.4; 95%CI 1.8, 10.6). Rough estimates of the annual risk of PFOA from the remaining six small, uncontrolled, observational studies (mean follow-up range: 5.7 to 23 years) ranged from 0% to 3.4%. This was not the primary aim of these studies, and limitations in design and methodology mean this data should be interpreted with caution. There is a paucity of high-quality evidence reporting a link between AKP and PFOA. Further, well-designed cohort studies may be able to fill this evidence gap.
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The etiology of patellofemoral pain is likely related to pathological femoral shape and soft-tissue restraints imbalance. These factors may result in various maltracking patterns in patients with patellofemoral pain. Thus, we hypothesized that femoral shape influences patellofemoral kinematics, but that this influence differs between kinematically unique subgroups of patients with patellofemoral pain. 3D MRIs of 30 knees with patellofemoral pain and maltracking ("maltrackers") and 33 knees of asymptomatic subjects were evaluated, retrospectively. Dynamic MRI was acquired during a flexion-extension task. Maltrackers were divided into two subgroups (nonlateral and lateral maltrackers) based on previously defined kinematic criteria. Nine measures of femoral trochlear shape and two measures of patellar shape were quantified. These measures were correlated with patellofemoral kinematics. Differences were found in femoral shape between the maltracking and asymptomatic cohorts. Femoral shape parameters were associated with patellar kinematics in patients with patellofemoral pain and maltracking, but the correlations were unique across subgroups within this population. The ability to better categorize patients with patellofemoral pain will likely improve treatment by providing a more specific etiology of maltracking in individual patients.
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Mechanical factors related to patellofemoral pain syndrome and maltracking are poorly understood. Clinically, the Q-angle, J-sign, and lateral hypermobility commonly are used to evaluate patellar maltracking. However, these measures have yet to be correlated to specific three-dimensional patellofemoral displacements and rotations. Thus, we tested the hypotheses that increased Q-angle, lateral hypermobility, and J-sign correlate with three-dimensional patellofemoral displacements and rotations. We also determined whether multiple maltracking patterns can be discriminated, based on patellofemoral displacements and rotations. Three-dimensional patellofemoral motion data were acquired during active extension-flexion using dynamic MRI in 30 knees diagnosed with patellofemoral pain and at least one clinical sign of patellar maltracking (Q-angle, lateral hypermobility, or J-sign) and in 37 asymptomatic knees. Although the Q-angle is assumed to indicate lateral patellar subluxation, our data supported a correlation between the Q-angle and medial, not lateral, patellar displacement. We identified two distinct maltracking groups based on patellofemoral lateral-medial displacement, but the same groups could not be discriminated based on standard clinical measures (eg, Q-angle, lateral hypermobility, and J-sign). A more precise definition of abnormal three-dimensional patellofemoral motion, including identifying subgroups in the patellofemoral pain population, may allow more targeted and effective treatments.
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To quantify normal motion, medial and lateral passive patellar motion limits were measured in 67 high school athletes randomly selected from a group of 1340 ath letes undergoing preseason physical examinations. Pa tellar displacement was measured at knee flexion an gles of 0° and 35°, using both a Patella Pusher (a hand held force gauge) and a manual technique, and the results were compared. Demographic data and physical examination of the deceleration mechanism (Q angle, vastus medialis obliquus dysplasia, patella alta and baja, and valgus and varus alignment) were correlated with patellar motion limits. With the knee in extension, passive displacement of the patella averaged 9.6 mm medially and 5.4 mm laterally. In flexion, medial displacement averaged 9.4 mm and lateral displacement averaged 10.0 mm. No positive correlations were found between demographic data or deceleration mechanism examination parame ters and patellar motion limits, suggesting that motion produced by the displacement force was limited by ligamentous restraints only. The clinical assessment of the passive limits of pa tellar motion should include examination at knee flexion angles of 0° and 35°. The manually produced displace ment was found to be more reproducible than displace ment by the Patella Pusher (P < 0.05).
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Many variables have retrospectively been associated with the presence of anterior knee pain. Very few prospective data exist, however, to determine which of these variables will lead to the development of anterior knee pain. It was our purpose in this study to determine the intrinsic risk factors for the development of anterior knee pain in an athletic population over a 2-year period. Before the start of training, 282 male and female students enrolled in physical education classes were evaluated for anthropometric variables, motor performance, general joint laxity, lower leg alignment characteristics, muscle length and strength, static and dynamic patellofemoral characteristics, and psychological parameters. During this 2-year follow-up study, 24 of the 282 students developed patellofemoral pain. Statistical analyses revealed a significant difference between those subjects who developed patellofemoral pain and those who did not concerning quadriceps and gastrocnemius muscle flexibility, explosive strength, thumb-forearm mobility, reflex response time of the vastus medialis obliquus and vastus lateralis muscles, and the psychological parameter of seeking social support. However, only a shortened quadriceps muscle, an altered vastus medialis obliquus muscle reflex response time, a decreased explosive strength, and a hypermobile patella had a significant correlation with the incidence of patellofemoral pain. We concluded that the latter four parameters play a dominant role in the genesis of anterior knee pain and we therefore deem them to be risk factors for this syndrome.
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Patellofemoral pain syndrome (PFPS) is one of the most common musculoskeletal disorders. However, no consensus on the definition, classification, assessment, diagnosis, or management has been reached. We evaluated symptoms and clinical findings in subgroups of individuals with PFPS, classified on the basis of the findings in radiological examinations and compared the findings with knee-healthy subjects. An orthopedic surgeon and a physical therapist consecutively examined 80 patients clinically diagnosed as having PFPS and referred for physical therapy. The examination consisted of taking a case history and clinical tests. Radiography revealed pathology in 15 patients, and scintigraphic examination revealed focal uptake in 2 patients indicating pathology (group C). Diffusely increased uptake was present in 29 patients (group B). In the remaining 29 patients radiographic and scintigraphic examinations were normal (group A). Knee-healthy controls (group D) reported no clinical symptoms. No symptom could be statistically demonstrated to differ between the three patient groups. Knee-healthy subjects differed significantly from the three patient groups in all clinical tests measuring pain in response to the provocations; compression test, medial and lateral tenderness, passive gliding of the patella, but they also differed in Q angle. Differences in clinical tests between the patient groups were nonsignificant. The main finding in our study on patients clinically diagnosed with PFPS is that possible pathologies cannot be detected from the patient's history or from commonly used clinical tests.
Article
Treatment of patellofemoral pain syndrome (PFPS) has been extensively studied in physical therapy literature. Patients with PFPS demonstrate quadriceps and hip musculature weakness, altered lower extremity (LE) kinematics, and decreased LE flexibility. Psychosocial factors have also been identified as an important factor in patients with PFPS. The authors hypothesize that an ordered approach addressing each of these impairments sequentially will result in greater improvement in PFPS symptoms. The purpose of this pilot study was to assess the feasibility of performing a randomized trial and to determine the sample size necessary to examine the validity of this hypothesis. Patients received a sequential treatment approach using a PFPS treatment algorithm (PFPS Algorithm) designed by the authors. Patients were evaluated assessing psychosocial factors, flexibility, LE kinematics, and LE strength. Impairments that were found in the evaluation were addressed sequentially over the episode of care. Patients were prescribed therapy two times per week for six weeks. Pain, Anterior Knee Pain Scale (AKPS), and Global Rating of Change (GROC) were measured at evaluation and discharge. Thirty consecutive patients with PFPS who were referred to physical therapy were enrolled in the pilot study. All phases of the feasibility study including recruitment, treatment protocols and data collection were effectively carried out. One hundred percent of patients treated with the PFPS algorithm who completed the prescribed treatment had a clinically significant improvement in the AKPS and GROC. A floor effect was noted with NPRS with 38% of patients unable to achieve clinically significant improvement. With minor changes to the protocol and outcome measures used, a full randomized trial is feasible and merited. Steps must be taken to reduce the high drop-out rate among both groups. 1b.
Article
A retrospective survey of patellofemoral pain syndrome patients' physiotherapy records was undertaken to remedy the knowledge gap regarding symptoms, findings, treatments and outcomes. The survey findings concluded that only 46% of patients’ knees were pain free at discharge, highlighting a number of areas which require further research.
Article
Background and PurposePatellofemoral pain (PFP) is associated with a wide range of local and global physical factors possibly contributing to pain and thus requires detailed assessment and individualized treatment. Yet, no cohort study was found that assessed the value of individualized physiotherapy, probably because this approach lends itself to clinical practice but not to scientific research. Most studies focus on a ‘knee’ or ‘hip’ treatment approach irrespective of individual global differences in lower limb alignment, movement patterns and muscle tightness. Therefore, this study aimed to determine the effectiveness of supplementing local treatment of PFP with individualized treatment targeting global contributing factors. Secondarily it aimed to subgroup the patients according to variations in lower limb alignment/laxity, movement patterns, biarticular muscle tightness and joint degeneration.Method Forty-one patients (60 knees) with PFP who had followed a programme of local quadriceps strengthening, quadriceps stretching and taping for one fortnight were prescribed an individualized programme based on assessment. This global assessment included lower limb postural alignment, movement patterns, muscle tightness and range of motion. Another fortnights treatment was prescribed accordingly and included specific, individualized postural and movement retraining, stretching and functional weight-bearing, strengthening exercises. Seven outcome measures, namely four pain measures, isokinetic quadriceps strength, quadriceps length and eccentric knee control, assessed improvement.ResultsAll outcome measures showed further significant improvement following individualized treatment (p < 0.03). Patients fell into four broad physical subgroups: hypermobility (often with malalignment), hypomobility (with three of four tight muscle groups), faulty movement patterns (mostly dynamic knee valgus) and patellofemoral osteoarthritis.Conclusions Individualized treatment supplementing local standard physiotherapy for PFP leads to further significant improvement over 2 weeks. This study highlights the importance of assessing patients globally in order to optimize treatment and ongoing improvement. Recognition of different subgroups may guide treatment that should include both local and deficit-targeted global treatment. Copyright © 2014 John Wiley & Sons, Ltd.
Article
Objectives To understand how instructing females with patellofemoral pain to correct dynamic knee valgus affects pelvis, femur, tibia and trunk segment kinematics. To determine if pain reduction in the corrected condition was associated with improved segment kinematics. Design Cross-sectional. Methods A 3D-motion capture system was used to collect multi-joint kinematics on 20 females with dynamic knee valgus and patellofemoral pain during a single-leg squat in two conditions: usual movement pattern, and corrected dynamic knee valgus. During each condition pain was assessed using a visual analog scale (VAS). Pelvis, femur, tibia and trunk kinematics in the frontal and transverse planes were compared between conditions using a paired T-test. Pearson correlation coefficients were generated between VAS score and the kinematic variables in the corrected condition. Results In the corrected condition subjects had increased lateral flexion of the pelvis toward the weight-bearing limb (p < 0.001), decreased femoral adduction (p = 0.001) and internal rotation (p = 0.01). A trend toward decreased tibial internal rotation (p = 0.057) and increased trunk lateral flexion toward the weight-bearing limb (p = 0.055) was also found. Lower pain levels were associated with less femoral internal rotation (p = 0.04) and greater trunk lateral flexion toward the weight-bearing limb (p = 0.055). Conclusions Decreased hip adduction after instruction was comprised of motion at both the pelvis and femur. Decreased pain levels were associated with lower extremity segment kinematics moving in the direction opposite to dynamic knee valgus. These results increase our understanding of correction strategies used by females with patellofemoral pain and provide insight for rehabilitation.
Article
Patellofemoral pain (PFP) remains one of the most common conditions encountered in sports medicine. Characterised by anterior knee pain that is aggravated by activities such as running, squatting and stair ambulation; PFP generally reduces or restricts physical activity. While PFP may subside with activity reduction, the natural history of this common condition is not one of spontaneous recovery. Indeed, PFP is often recalcitrant and can persist for many years. In a prospective study of people with PFP, symptoms persisted in 25% of people up to 20 years.1 Despite considerable evidence for the efficacy of conservative interventions for PFP, such as multimodal physiotherapy,2 these interventions do not appear to have long-lasting effects.2 Compounding the management of PFP is that surgery for PFP is widely considered to have poor outcomes. Are PFP and osteoarthritis on a disease continuum? As mentioned in the 2014 consensus statement from the International Patellofemoral Pain Research Retreat3 there is speculation that PFP may be a prelude to degenerative joint changes and ultimately the development of patellofemoral osteoarthritis (PFOA).4 ,5 While no current studies have prospectively studied people with PFP through to the development of PFOA (and thus verify this relationship), a recent systematic review4 observed that individuals undergoing arthroplasty for PFOA were more than twice as likely (OR=2.31, 95% CI 1.37 to 3.88) to report having had PFP as an adolescent than patients undergoing an arthroplasty for isolated tibiofemoral OA. In the absence of rigorous …
Article
Three different methods for testing all pairs of $\overline{{\rm Y}}_{\text{k}}-\overline{{\rm Y}}_{\text{k}}$, were contrasted under varying sample size (n) and variance conditions. With unequal n's of six and up, only the Behrens-Fisher statistic provided satisfactory control of both the familywise rate of Type I errors and Type I error rate on each contrast. Satisfactory control with unequal n's of three and up is dubious even with this statistic.
Article
To define research priorities to strategically inform the evidence base for physiotherapy practice. A modified Delphi method using SurveyMonkey software identified priorities for physiotherapy research through national consensus. An iterative process of three rounds provided feedback. Round 1 requested five priorities using pre-defined prioritisation criteria. Content analysis identified research themes and topics. Round 2 requested rating of the importance of the research topics using a 1-5 Likert scale. Round 3 requested a further process of rating. Quantitative and qualitative data informed decision-making. Level of consensus was established as mean rating ≥ 3.5, coefficient of variation ≤ 30%, and ≥ 55% agreement. Consensus across participants was evaluated using Kendall's W. Four expert panels (n=40-61) encompassing a range of stakeholders and reflecting four core areas of physiotherapy practice were established by steering groups (n=204 participants overall). Response rates of 53-78% across three rounds were good. The identification of 24/185 topics for musculoskeletal, 43/174 for neurology, 30/120 for cardiorespiratory and medical rehabilitation, and 30/113 for mental and physical health and wellbeing as priorities demonstrated discrimination of the process. Consensus between participants was good for most topics. Measurement validity of the research topics was good. The involvement of multiple stakeholders as participants ensured the current context of the intended use of the priorities. From a process of national consensus involving key stakeholders, including service users, physiotherapy research topics have been identified and prioritised. Setting priorities provides a vision of how research can contribute to the developing research base in physiotherapy to maximise focus.
Article
In recent years, there has been a growing interest among researchers in the use of latent class and growth mixture modeling techniques for applications in the social and psychological sciences, in part due to advances in and availability of computer software designed for this purpose (e.g., Mplus and SAS Proc Traj). Latent growth modeling approaches, such as latent class growth analysis (LCGA) and growth mixture modeling (GMM), have been increasingly recognized for their usefulness for identifying homogeneous subpopulations within the larger heterogeneous population and for the identification of meaningful groups or classes of individuals. The purpose of this paper is to provide an overview of LCGA and GMM, compare the different techniques of latent growth modeling, discuss current debates and issues, and provide readers with a practical guide for conducting LCGA and GMM using the Mplus software.
Article
Background and Purpose This work represents part of a PhD project investigating outcome measures for patellofemoral joint problems – critical angle and angular velocity as measured by video analysis of an eccentric step test, a treadmill test and a Modified Functional Index Questionnaire (MFIQ). This paper describes the development of the outcome measures and provides experimental data to support their validity. Methods A controlled repeated measures study was carried out in the physiotherapy department at Burnley General Hospital, where 88 patients were considered for inclusion. Comparing experimental data collected from the patients with those previously published provided estimates of the validity of the outcome measures. Results Mean critical angle was 57.8° and mean angular velocity was 93°/sec. The eccentric step test was found painful by 74% of patients. Data from the treadmill test were right censored with 49% of patients completing 300 seconds without pain. Cronbach's alpha for the MFIQ was 0.83. Conclusion When comparing video data from this patient group to a previous study of 100 healthy subjects the patients demonstrate an earlier critical angle and faster angular velocity. These data suggest that the measurements of critical angle and angular velocity through video analysis of an eccentric step test are valid measures of patellofemoral joint dysfunction. As treadmill test data are right censored it suggests that the test in the form used in this study is valid for only about 50% of the patients. The high value recorded for Cronbach's alpha suggests that the MFIQ is internally consistent, which in turn suggests it is also a valid measure of patellofemoral dysfunction.
Article
The aim of this study was to determine whether measures of obesity and adiposity are associated with the rate of patella cartilage volume loss in healthy adults. 297 community-based adults aged 50-79 years with no clinical knee osteoarthritis were recruited at baseline (2003-4). 271 (62% female) subjects were re-examined at follow-up (2006-7). Measures of obesity (body mass index (BMI) and weight) and adiposity (fat mass and percentage fat mass), as well as patella cartilage volume, were determined by established protocols. Patella cartilage volume was lost at an annual rate of 1.8% (95% CI 1.4% to 2.1%). Increased baseline BMI, weight, fat mass and percentage fat mass were all associated with an increased rate of patella cartilage volume loss after adjustment for confounders (all p< or =0.04). The direction and magnitude of the effects were similar for both sexes but the number of men examined was considerably smaller and the associations were not statistically significant. There were no significant associations observed between change in any of the obesity and adiposity measures and the rate of patella cartilage volume loss. This study demonstrated that increased levels of obesity and adiposity are associated with an increased annual rate of patella cartilage volume loss in healthy adults. Weight-loss interventions that reduce body mass, or specifically target a reduction in fat mass, may help to reduce the rate at which patella cartilage volume is lost, and subsequently the risk of patellofemoral osteoarthritis.