Article

Joint Loading With Valgus Bracing in Patients With Varus Gonarthrosis

Authors:
  • Hewett Consultants - Rochester, Minneapolis
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Abstract

The purpose of this study was to determine whether a brace designed to unload varus degenerative knees actually alters medial compartment loads by decreasing the adduction moment. Eleven patients who had arthrosis confined to the medial compartment were fitted with a valgus brace and tested before and after brace wear with pain and function scoring instruments and by automated gait analysis. The biomechanical data from these patients were compared with those from 11 healthy control subjects. Scores from an analog pain scale decreased 48% with brace wear, and function with activities of daily living increased 79%. Mean adduction moment without the brace measured 4.0 +/- 0.8% body weight times height versus 3.6 +/- 0.8% body weight times height when wearing the brace (10% decrease). The mean adduction moment for control subjects was 3.5 +/- 0.6% body weight times height. Thus, the mean adduction moment decreased from approximately one standard deviation from the normal mean to a value that is similar to the control value. Nine of 11 patients had a decrease in the adduction moment with the brace, five of 11 patients had a reduction higher than 10%, and decreases in this moment were as high as 32%. This study shows that pain, function, and biomechanical knee loading can be altered by a brace designed to unload the medial compartment of the knee.

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... In these studies, walking speed was used most often for outcome. Several studies demonstrated beneficial effect of unloader knee bracing on walking speed 15,17,20,23 ; however, there were conflicting results in other studies which showed walking speed was not significantly changed 19,21,22,24,25,26 . ...
... The biomechanical effect of unloader knee braces on gait was mainly evaluated using the following variables: external knee adduction moment 12,13,14,15,16,17,19,20,21,23,24,25,26 , ground reaction force (GRF) 12,14,15,21,25,27 and joint angle 11,12,14,17,19,20,27 . The knee adduction moment is an indirect measure of medial tibiofemoral compartment loading. ...
... Unloader knee braces are designed to reduce the load on the painful medial compartment by application of an external valgus moment through a three-point force system of action about the knee joint. In the past, several studies showed the load- 24,26 . Results of our study suggested the mechanism of immediate decrease in knee pain might be the result of decreased adduction moment, especially at 2 nd peak. ...
Article
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Gait modification is frequently used as conservative management in knee osteoarthritis (OA). Knee orthoses, such as knee sleeves and unloader knee braces, are nonpharmacological treatment for gait modification in symptomatic knee OA. Previous studies lack systematic investigation of biomechanical effect and functional capacity, particularly walking capacity. This study investigated effects of knee orthoses on biomechanics and walking capacity in patients with knee OA. A literature search was conducted in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Physiotherapy Evidence Database (PEDro), and Cochrane Central Register of Controlled Trials (CENTRAL) according to inclusion criteria from 1966 to May 2013. Trials investigating the effects of knee orthoses on biomechanics or walking capacity were collected. Effect size was calculated exclusively according to biomechanical and walking capacity variables reported over 5 publications. Narrative analysis of the studies was performed. The database search provided a total of 1681 citations with 19 studies that investigated effect of neoprene sleeves and unloader knee braces, and satisfied the inclusion criteria. Of these, one was a randomized controlled trial; the other 18 studies were within-subjects, repeated measures designs. Study results indicated unloader knee braces could decrease knee adduction moment, particularly the 2nd peak during walking, compared to controls. However, unloader knee braces did not improve walking endurance, and effects on walking speed differed between studies. Load-reduction effects of unloader braces used while walking coincide with clinical observations of pain reduction. Our results suggest the mechanism of immediate decrease in knee pain may be due to decreased adduction moment especially at the 2nd peak, though this may not affect walking capacity. The conclusions of this review are limited by methodological considerations; therefore, high-quality randomized controlled trials concerning bracing biomechanical changes and functional capacity for knee OA are still necessary.
... The most frequent reported secondary outcome measure was pain. Nine studies reported a decrease of pain in braced patients [5,13,16,18,19,24,26,32,36]. One of those studies showed no significant change in the adduction moment [16]. ...
... Three studies could show that valgus bracing increased gait speed [1,14,26] and two studies could show that valgus bracing increased step length [1,26]. One study found that use of a valgus brace reduced gait asymmetry between the braced and contralateral legs during walking [36]. ...
... Three studies could show that valgus bracing increased gait speed [1,14,26] and two studies could show that valgus bracing increased step length [1,26]. One study found that use of a valgus brace reduced gait asymmetry between the braced and contralateral legs during walking [36]. ...
Article
Full-text available
Purpose: There is a lack of consensus regarding biomechanical effects of unloader braces for the treatment of medial osteoarthritis (OA) of the knee. The purpose of this study was to perform a systematic review of studies examining the biomechanical effect of unloader braces. Methods: A systematic search for articles about the biomechanical effect of unloader braces was performed. Primary outcome measure was the influence of the brace on the knee adduction moment. Data sources were Pubmed central and google scholar. Results: Twenty-four articles were included. Twenty articles showed that valgus unloader braces significantly decrease the knee adduction moment. Seven of those studies reported a decrease of pain in braced patients (secondary outcome measure). Positive effects on the knee adduction moment could be found for custom made braces for conventional knee braces and for a foot ankle orthosis. Four studies could not show any effect of knee unloader braces on the knee adduction moment although one of these studies found decreased pain in braced patients. One of these studies examined healthy patients with a neutral axis. Conclusion: This systematic review could demonstrate evidence that unloader braces reduce the adduction moment of the knee. Foresighted, a systematic review about the clinical effect of unloader braces is required.
... Four studies (of 17 studies that reported results for the external KAM) also described the effects of valgus knee bracing on the sagittal plane moment 32,34,47,50 . Two studies 32,34 reported no significant difference with and without wearing the brace, while the other two studies reported variable results. ...
... Four studies (of 17 studies that reported results for the external KAM) also described the effects of valgus knee bracing on the sagittal plane moment 32,34,47,50 . Two studies 32,34 reported no significant difference with and without wearing the brace, while the other two studies reported variable results. Toriyama et al. ...
... Importantly, the external KAM represents the medial-to-lateral distribution of knee joint load rather than the actual force on the medial compartment 52,62 , and proposed beneficial decreases in the KAM must be interpreted cautiously in situations where the total joint contact force may increase 52,62,63 . When considering the other biomechanical measures investigated, the fact that four studies reported small to no change in the external KFM 32,34,47,50 , two studies suggested a decrease in knee extensor and flexor muscle cocontraction 46,54 , and two studies reported an increase in medial joint space 36,43 , these overall findings are consistent with directly measured decreases in medial contact force with valgus brace use. The magnitude of these effects remains unclear, however, with some authors suggesting the size of the decrease in load on the medial compartment observed with bracing is too small to be of much benefit, while other authors suggesting even small changes in knee joint loading may be important given the thousands of steps taken per day 9,32,45,48,51,55,56 . ...
Article
To review and synthesize the biomechanical effects of valgus knee bracing for patients with medial knee osteoarthritis.Methods Electronic databases were searched from their inception to May 2014. Two reviewers independently determined study eligibility, rated study quality and extracted data. Where possible, data were combined into meta-analyses and pooled estimates with 95% confidence intervals (CI) for standardized mean differences (SMD) were calculated.ResultsThirty studies were included with 478 subjects tested while using a valgus knee brace. Various biomechanical methods suggested valgus braces can decrease direct measures of medial knee compressive force, indirect measures representing the mediolateral distribution of load across the knee, quadriceps/hamstring and quadriceps/gastrocnemius co-contraction ratios, and increase medial joint space during gait. Meta-analysis from 17 studies suggested a statistically significant decrease in the external knee adduction moment during walking, with a moderate-to-high effect size (SMD=0.61; 95%CI: 0.39, 0.83; p<0.001). Meta-regression identified a near-significant association for the knee adduction moment effect size and duration of brace use only (β, -0.01; 95% CI: -0.03, 0.0001; p=0.06); with longer durations of brace use associated with smaller treatment effects. Minor complications were commonly reported during brace use and included slipping, discomfort and poor fit, blisters and skin irritation.Conclusions Systematic review and meta-analysis suggests valgus knee braces can alter knee joint loads through a combination of mechanisms, with moderate-to-high effect sizes in biomechanical outcomes.
... One of the suggested options is by reducing the KAM [9, 10]. KAM can be reduced through a variety of methods including surgical interventions such as high tibial osteotomy (HTO) [12], and non-surgical interventions such as assistive devices including unloading braces [13,14], lateral wedged insoles (LWIs) [15,16] or walking poles [17]. KAM reduction is highest in the case of HTO, between 31 and 58% [18][19][20][21], but this has risks associated with the surgery [22]. ...
... KAM reduction is highest in the case of HTO, between 31 and 58% [18][19][20][21], but this has risks associated with the surgery [22]. Reduction of KAM with unloader braces is lower, between 10 and 13% [13,14] and with LWIs it is between nine and 12% [15,16]. However, compliance with such devices is generally low [23][24][25][26] due to skin irritation, swelling or inconvenience of use [23]. ...
... Due to the sample size in our study, sub-group analysis to investigate this relationship was not possible. During natural walking, the seven percent reduction in first peak KAM as a result of the gait retraining program was lower than that reported in knee braces (10-13%) [13,14], lateral wedges (nine to 12%) [15,16] and walking poles (six to 33%) [27]. However, during the retention trial, the change in KAM was similar to that achieved using assistive devices (14%). ...
Article
Background: The knee adduction moment (KAM) is often elevated in medial knee osteoarthritis (KOA). The aim of this study was to evaluate effects on KAM and patient-reported outcomes of a six-week gait training program. Methods: Twenty-one patients (61 ± 6 years) with KOA participated in a six-week biofeedback training program to encourage increased toe-in (all patients) and increased step-width (five patients). Patients received real-time visual feedback while walking on an instrumented treadmill. We analysed the effect of the gait modification(s) on peak KAM in week six and three and six months post-training. We also evaluated the effect on pain and functional ability. Results: Of 21 patients starting the program, 16 completed it with high attendance (15 and 16 respectively) at the three and six month follow-ups. First peak KAM was significantly reduced by up to 14.0% in week six with non-significant reductions of 8.2% and 5.5% at the follow-ups. Functional ability (assessed using the WOMAC questionnaire) improved significantly after the training (eight point reduction, p = 0.04 in week six and nine point reduction, p = 0.04 at six-month follow-up). There was also a trend towards reduction in WOMAC pain (p = 0.06) at follow-up. Conclusions: Biofeedback training to encourage gait modifications is feasible and leads to short-term benefits. However, at follow-up, reductions in KAM were less pronounced in some participants suggesting that to influence progression of KOA in the longer term, a permanent regime to reinforce the effects of the training program is needed. Trial number: ISRCTN14687588.
... Studies into knee braces date back into the 20th century. Although the studies of Lindenfeld et al, 12 in 1997, and Kirkley et al, 13 in 1999, are small, they found that valgus knee braces were able to reduce pain and improve function. Also, Katsuragawa et al 14 demonstrated that valgus bracing in patients with medial compartmental osteoarthritis can alter mechanical alignment and increase bone mineral density in the lateral side of the femur and tibia. ...
... It has a 3-point leverage system which is able to unload the affected compartment and is recommended for mild to severe unicompartmental osteoarthritis. 15 The studies by Lindenfeld et al, 12 Kirkley et al 13 and Katsuragawa et al 14 showed that there is some evidence to support unloader knee braces published over 10 years ago. However, in the past 10 years people's lifestyles have changed and the prevalence of osteoarthritis has increased. ...
Article
Full-text available
Background The incidence of osteoarthritis is increasing and it is one of the most common causes of chronic conditions. Total knee replacement is the mainstay of treatment for end-stage knee osteoarthritis; however, with long waiting lists and high levels of dissatisfaction, a treatment like knee braces could potentially delay surgery. Unicompartmental knee osteoarthritis is associated with misalignment of the knee, and unloader bracing has been recommended by various guidelines to correct this misalignment. The aim of this report was to provide an update of evidence from the past 10 years on knee braces. Methods MEDLINE/EMBASE search was performed from the past 10 years. Results We reviewed the evidence from 14 published articles. Almost all articles supported knee brace use and showed it to decrease pain, improve function, and improve the quality of life of patients. One study in 2017 followed patients for long term and found knee bracing to be more cost effective than total knee replacement, and could replace the need for surgery. Several minor complications were reported with bracing, like soft tissue irritation, which could be due to poor fitting. A management strategy for this could be regular follow-up at a nurse-led clinic. Conclusions Unloader braces are an economical and effective treatment for unicompartmental knee osteoarthritis. They can significantly improve a patient's quality of life and potentially delay the need for surgery. Patients should be managed with a multidisciplinary approach with conservative management and knee bracing, before surgery is considered.
... This finding agrees with other studies which found comparable reductions of the KAM by valgus bracing. 18,19,[27][28][29][30][31][32][33][34][35][36] In our study, the KAM for the individual and reduced orthosis settings compared to unbraced settings showed reductions of up to 18% and 15% for LP and up to 16% and 13% for PO, respectively. These results underline a certain clinical relevance as KAM compensations of around 10% were thought to be the main mechanism for pain relief and overall function in knee OA. 36 The measured reductions were also comparable to those reported previously. ...
... This is in agreement with previous studies, which demonstrated that toeing out was not changed by knee bracing. 17,31 Nonetheless, we assume that a combination of both maintenance of external foot rotation and reduced knee varus might be the mechanism of reducing medial knee load in valgus bracing. In our study, the frontal knee angle was significantly reduced by wearing the knee orthosis. ...
Article
Background: Valgus bracing in medial knee osteoarthritis aims to improve gait function by reducing the loading of the medial compartment. Orthosis composition and optimal adjustment is essential to achieve biomechanical and clinical effectiveness. Objectives: To investigate biomechanical functionality during gait, pain relief and compliance in patients with knee osteoarthritis using a lightweight adjustable knee unloader orthosis. Study design: Prospective observational clinical trial. Methods: Instrumented gait analysis in 22 patients with unilateral medial knee osteoarthritis was performed after a 2-week orthosis acclimatisation period. Kinematics and kinetics during gait as well as force transmission from the orthosis to the knee were analysed. Measurements were performed without, at individualised and at reduced orthosis setting. The assessment was supplemented by patient-related pain sensation and compliance questionnaires. Results: Orthosis wear significantly reduced the knee adduction moment by up to 20% depending on orthosis adjustment, whereas pain sensation was significantly reduced by 16%. A significant positive correlation was found between force transmissions and knee adduction moment as well as for frontal knee angle. Compliance was good with a main daily use of 2-6 h. Conclusion: The orthosis provides significant biomechanical improvements, pain relief and good patient compliance. Patients had a biomechanical benefit for the individualised and reduced orthosis adjustments. Clinical relevance In patients with medial knee osteoarthritis, a lightweight medial unloader orthosis effectively reduced external knee adduction moment and pain sensation during daily activities. Thus, use of lightweight orthoses effectively supports conservative treatment in medial knee osteoarthritis.
... This study follows a protocol similar to past studies (Draganich et al., 2006;Lindenfeld et al., 1997;Pollo et al., 2002) and evaluates the effect of the unloader brace on medial and lateral knee joint loads during gait. ...
... The consistency in peak adduction moment for both braced and unbraced conditions from Visit 1 to Visit 2 of the affected limb support previous studies which indicate that the mechanical effects of an unloader brace occur immediately upon brace application (Draganich et al., 2006). As well, the decrease in peak external adduction moment about the knee between the brace and unbraced conditions for the affected limb is consistent with previous studies (Draganich et al., 2006;Lindenfeld et al., 1997;Pollo et al., 2002). The decreases in lever arm with no change in GRF may indicate that the reduction in adduction moment is a result of the brace. ...
... Various treatment options available are conservative that encompasses the life style modifications, NSAIDS, physical therapies like hot wet packs/ice packs/ultra violet rays/paraffin wax bath, exercise program, intraarticular steroid injections, viscosupplementation, biological agents like platelet rich plasma, modified footwear and assistive devices like lateral insole wedges with or without subtalar strapping, variable stiffness shoes with softer medial side, abduction knee braces using three-point bending. [9][10][11][12][13][14] But once all these modalities of treatment are exhausted due to progression of disease or are non-responsive, then surgical intervention becomes inevitable, such as high tibial osteotomy, unicondylar/total knee replacement (UKR/TKR). Under the shadow of the complications associated with osteotomy and UKR/TKR there had been a continuous desire to develop a technique to relieve the pain of moderate to severe OA of medial compartment and which should be possibly least invasive and should not commensurate with problems of aforesaid procedures. ...
Article
Full-text available
p class="abstract"> Background: The medial compartmental osteoarthritis (OA) knee is initially treated conservatively followed by lateral close/open medial wedge high tibial osteotomy (HTO), or by unicompartmental or total knee replacement (UKR/TKR). Though HTO and UKR/TKR yield good results but are technically more demanding and are fraught with risk of complications, moreover replacement may not be the treatment of choice for younger patients. The objective of this study was to evaluate the efficacy of proximal fibular osteotomy (PFO), a minimally invasive procedure minus risks associated with HTO/TKR. Methods: Thirty-eight patients, 15 males and 23 females with a mean age of 54.46 years (range, 35 to 80 years) underwent PFO for OA knee and were followed for a mean period of 8.63 months (range 6 to 12 months). Results: After PFO all patients experienced immediate significant relief in medial knee pain with improved walking distance. Postoperatively, all patients showed radiological improvement in femorotibial angle (FTA), medial/lateral joint space ratio. Conclusions: PFO is safe, minimally invasive technique with minimal complications. It gives immediate relief of medial knee pain with improved function of joint.</p
... They can also provide short-term improvements infunctional disabilities and quality of life for knee OA patients [9]. Previous studies demonstrated that braces treat knee OA by extending the condylar separation of the medial compartment [10], thus reducingthe external knee adduction moment during gait [11][12][13] and the medial compartment load at the knee [13,14]. In the clinical setting, many patients treated with knee bracing complained that the braces were heavy and complicated to fit, and that longterm fittings caused skin problems. ...
... There is no consensus in the literature on efficacy of a decompressive bracing on first peak KAM reduction, which in part may explain underutilization of bracing in management of knee OA. Some studies have demonstrated significantly reduced first peak KAM 26,27,35,37 while others have not. 21,34,36 Participants in this study experienced a decrease in first peak KAM while wearing the decompressive brace but it did not reach statistical significance at 2 weeks (13%) or 8 weeks (16%) when compared to baseline. ...
Article
Full-text available
Knee osteoarthritis is a prevalent disease. Unloading the affected compartment using a brace is a treatment option. To determine whether a decompressive knee brace alters loading in medial knee osteoarthritis following 2 and 8 weeks of use. Within subjects; pre- and post-testing. A total of 15 individuals with medial knee osteoarthritis attended four sessions: baseline, fitting, 2 weeks after fitting (post), and 8 weeks after fitting (final). A gait analysis was performed at baseline (without knee brace), post and final. Knee adduction impulse, first and second peak knee adduction moment, knee motion, and walking velocity were calculated. Participants also recorded hours and steps taken while wearing the brace. On average, the brace was worn for more than 6 h/day. Through use of repeated-measures analysis of variance, it was determined that the knee adduction impulse and second peak knee adduction moment were reduced (p < 0.05) at post and final compared to baseline (36% and 34% reduction in knee adduction impulse, 26% reduction in second peak knee adduction moment for post and final, respectively). Furthermore, participants walked faster with increased knee motion during stance. The studied decompressive brace was effective in reducing potentially detrimental forces at the knee-knee adduction impulse and second peak knee adduction moment during the stance phase of gait. The data from this study suggest that use of a medial unloading brace can reduce potentially detrimental adduction moments at the knee. Clinicians should use this evidence to advocate for use of this noninvasive treatment for people presenting with medial knee osteoarthritis. © The International Society for Prosthetics and Orthotics 2015.
... The medial compartment is most frequently affected (85%), even without any misalignment in the lower limbs [4][5][6] and the load on this compartment increases rapidly in cases of constitutional or acquired genu varum. This load can be estimated indirectly by analyzing the knee adduction moment [7][8][9] which correlates well with knee pain and joint space narrowing [10][11][12]. ...
Conference Paper
Background Non-pharmacological therapies are recommended for the care of knee osteoarthritis patients. Unloader knee braces provide an interesting functional approach, which aims to modulate the mechanical stress on the symptomatic joint compartment. We aimed to confirm the biomechanical effects and evaluate functional benefits of a new knee brace that combines a valgus effect with knee and tibial external rotation during gait in medial osteoarthritis patients. Methods 20 patients with unilateral symptomatic medial knee osteoarthritis were included and performed two test sessions of 3D gait analysis with and without the brace at the initial evaluation (W0) and after 5 weeks (W5) of wearing the brace. VAS-Pain, Satisfaction scores, WOMAC scores, spatio-temporal gait parameters (gait speed, stride length, stance and double stance phase, step width), biomechanical data of the ipsilateral lower limb (hip, knee ankle and foot progression angle) were recorded at each session Results VAS-pain and WOMAC significantly decreased at W5. Walking speed was not significantly modified by knee bracing at W0, but increased significantly at W5. Knee adduction moments and foot progression angles significantly decreased in the terminal stance and push off, respectively, with bracing at W0 and W5. Lower-limb joint angles, moments and powers were significantly modified by wearing the brace at W0 and W5. Conclusions This new knee brace with distraction-rotation effects significantly alters knee adduction moments and foot progression angles during gait, which might lead to significant functional gait improvements and have carry-over effects on pain at the short term in osteoarthritis patients (<2 months). Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.1930
... 6 Increased activity and reduced pain might then delay the need for operation. 7,8 Several studies on the use of valgus braces report that patients have considerable relief from pain, improved function, 6-10 and a reduction in loading of the medial compartment. 11 Few studies have considered whether biomechanical changes relate to these perceived benefits. ...
... Some intrinsic and extrinsic mechanical interventions aim to lower the moment arm of the ground reaction force about the knee in the frontal plane by changing the alignment of the limb from a varus alignment closer to a neutral alignment. The efficacy in shifting the load from the medial to the lateral compartment is very good for intrinsic mechanical interventions to treat static varus malalignment such as high tibial osteotomy (up to À40%) [8] while the efficacy of extrinsic mechanical interventions including footwear modifications and bracing have been moderate (up to À15%) [9][10][11][12][13]. Other intrinsic interventions have focused on a change of the neuromuscular control of ambulation and concen-trated on quadriceps strengthening [14][15][16][17][18]. ...
... The first key observation from the current research is that knee bracing did not significantly influence joint kinetics in any of the movements. This finding disagrees with those of Lindenfeld, Hewett, and Andriacchi (1997) and Pagani, Potthast, and Brüggemann (2010) who demonstrated reductions in knee kinetic parameters whilst wearing knee braces, but does concur with the observations of Gaasbeek, Groen, Hampsink, Van Heerwaarden, and Duysens (2007) and Sinclair et al. (2016). It is proposed that this disagreement between studies may relate to the wide range of different of knee braces and participant groups that have been used in biomechanical and clinical research settings. ...
Conference Paper
Introduction: Patellofemoral pain is one of the most common musculoskeletal pain conditions, with a multifactorial aetiology. It is reported that young females are at greater risk of developing patellofemoral pain. Knee braces are commonly used for patellofemoral pain; however the underlying mechanisms on the patellofemoral joint remains unclear. The aim of this study was to identify any changes in the kinetics and kinematics of the tibiofemoral joint in healthy subjects during a range of functional sport specific movements with and without a prophylactic knee sleeve. Methodology: Twenty female netball players aged between 18 and 30 years old (age= 20.95 ± 1.76 years, height = 1.67 ± 0.04 m, mass = 61.45 ± 7.04 kg) volunteered to participate in the study. Participants were asked to perform four tasks; running, cutting manoeuvre, countermovement vertical jump and a step-pivot movement, with and without the prophylactic knee sleeve (Trizone). Kinematic and kinetic data were recorded using 8 Oqus motion cameras and 1 embedded Kistler force platform. Participants were also asked to subjectively rate their knee stability using a Subjective Feedback Questionnaire. Results: The trizone sleeve led to a significant reduction in the knee peak range of motion in the transverse plane, specifically in the run, cut and pivot turn. The cutting manoeuvre displayed significantly higher moments in sagittal and coronal planes during loading, whereas the pivot turn show significantly higher moments in the transverse plane. Chi-squared test results showed a significant improvement in self-reported knee stability during the run, jump and pivot movements when wearing the brace. Discussion: This study identified potentially clinically meaningful differences in both the kinematics and self-reported knee stability when wearing prophylactic knee bracing during dynamic sporting tasks. It also provides insight into the aetiology of potential injury patterns and patellofemoral loading between different movement tasks that could increase the risk of patellofemoral pain development in female netball players. Further work is needed to identify the effect of such interventions on patellofemoral loading and neuromuscular control in individuals with knee pain during dynamic sporting tasks.
... This has spurred research efforts to reduce pain, preserve joints, delay replacement, and where possible restore joint function. High loads across the medial compartment of the OA knee in particular have been linked to both disease severity 1,2 and progression, 3 and so reduction of the loads at the knee is the basis for a number of potentially successful OA treatments, such as wedge insoles, braces, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and high tibial osteotomy. [24][25][26][27] A novel approach to reduce loads across the medial knee compartment is offered by the KineSpring system (Moximed, Hayward, CA, USA), which has been in clinical use for unicompartmental knee OA patients since mid-2008. ...
Article
Full-text available
The KineSpring implant system has been shown to provide load reductions at the medial compartment of the knee, and has demonstrated clinical success in reducing pain and increasing function in patients with medial knee osteoarthritis. These results depend on the ability of the KineSpring to rotate, lengthen, and shorten to accommodate knee motions, and in response to knee position and loading. The present study was undertaken to determine length changes of the implanted KineSpring in response to a range of knee positions, external knee loads, and placements by different orthopedic surgeons. KineSpring system components were implanted in ten cadaver leg specimens by ten orthopedic surgeons, and absorber-length changes were measured under combined loading and in different positions of the knee. Spring compression consistent with knee-load reduction, and device lengthening and shortening to accommodate knee loads and motions were seen. These confirm the functionality of the KineSpring when implanted medially to the knee.
... The first key observation from the current research is that knee bracing did not significantly influence joint kinetics in any of the movements. This finding disagrees with those of Lindenfeld, Hewett, and Andriacchi (1997) and Pagani, Potthast, and Brüggemann (2010) who demonstrated reductions in knee kinetic parameters whilst wearing knee braces, but does concur with the observations of Gaasbeek, Groen, Hampsink, Van Heerwaarden, and Duysens (2007) or Sinclair et al., (2016). It is proposed that this disagreement between studies may relate to the wide range of different of knee braces and participant groups that have been used in biomechanical and clinical research settings. ...
Article
Objective: To investigate the effects of a prophylactic knee brace on knee joint kinetics and kinematics during netball specific movements. Design: Repeated measures. Setting: Laboratory. Participants: Twenty university first team level female netball players. Outcome measurements: Participants performed three movements, run, cut and vertical jump under two conditions (brace and no-brace). 3-D knee joint kinetics and kinematics were measured using an eight-camera motion analysis system. Knee joint kinetics and kinematics were examined using 2 × 3 repeated measures ANOVA whilst the subjective ratings of comfort and stability were investigated using chi-squared tests. Results: The results showed no differences (p > 0.05) in knee joint kinetics. However the internal/external rotation range of motion was significantly (p < 0.05) reduced when wearing the brace in all movements. The subjective ratings of stability revealed that netballers felt that the knee brace improved knee stability in all movements. Conclusions: Further study is required to determine whether reductions in transverse plane knee range of motion serve to attenuate the risk from injury in netballers.
... There is no consensus in the literature on efficacy of a decompressive bracing on first peak KAM reduction, which in part may explain underutilization of bracing in management of knee OA. Some studies have demonstrated significantly reduced first peak KAM 26,27,35,37 while others have not. 21,34,36 Participants in this study experienced a decrease in first peak KAM while wearing the decompressive brace but it did not reach statistical significance at 2 weeks (13%) or 8 weeks (16%) when compared to baseline. ...
... Unter Bezugnahme auf Studien mit Nachweis biomechanischer Effekte (Reduktion KAM) [24] und klinischer Verbesserungen [25,26] ...
Article
Background Osteoarthritis is the most common joint disease worldwide and mostly affects the knee joint (gonarthrosis). In treatment algorithms, technical aids in the form of laterally wedged insoles, valgizing knee braces and ankle-foot orthoses have an importance in the treatment of medial unicompartmental knee joint disease. However, national and international guidelines differ in their recommendations. Insoles Taking into account a great amount of scientific work, the measurable effect of laterally wedged insoles appears to be low, so that a justifying indication only exists at low gonarthrosis levels. Knee braces Valgizing knee braces have shown stronger biomechanical and clinical effects, but with a slightly increased complication potential and low compliance. Low to medium-grade arthrosis can be treated. Ankle-foot orthoses Ankle-foot arthroses have not yet been conclusively examined. Initial work indicates biomechanical and clinical efficacy. The overall effects and indications appear comparable to knee braces, probably with less complication potential.
... One such treatment is the use of knee valgus braces, which are available as either custom-made or off-the-shelf (OTS) devices. Custom-made knee valgus braces have been shown to be more effective in reducing both the EKAM variables (first and second peak) and the knee varus angles than OTS devices, 5 with reductions in EKAM between 5.5% and 33% being demonstrated, 6,7 while other investigations have found no significant reductions in EKAM during walking [8][9][10] or during stair climbing. 10 One additional effect in one study has been a demonstrable reduction in knee flexion during swing phase. ...
Article
Full-text available
BACKGROUND: Knee valgus braces are used to reduce knee load and varus deformities in individuals with medial compartment osteoarthritis (OA). The purpose of this study was to determine whether the kinematics and kinetics of the knee are improved when wearing a knee-ankle-foot orthosis (KAFO) compared with knee valgus braces while walking and stair climbing. MATERIALS AND METHODS: One male individual (with 10° of knee varus) was assessed with a control shoe, custom, and off-the-shelf (OTS) Unloader knee valgus braces, and a custom-made KAFO in situ during walking and stair climbing. RESULTS: The KAFO significantly reduced the knee varus angle compared with the shoe and both knee valgus braces during walking and stair climbing, as well as the first peak of the external knee adduction moment (EKAM) during walking and the knee adduction angular impulse (KAAI) during ascending compared with the shoe. No significant differences were noted between the custom and OTS knee valgus braces in any measures. CONCLUSIONS: Knee-ankle-foot orthoses may be recommended for individuals with high knee varus angles.
... Patients with hip OA often experience decreased external hip joint moments and especially a decreased hip extension moment (HEM) is significantly correlated with increased pain (Hurwitz et al., 1997). In clinical environments, joint loadings, particularly KAM, are used to conclude about various therapies, e.g., physiotherapy or gait retraining (Shull et al., 2013;van Rossom et al., 2018), treatment with insoles or orthoses (Lindenfeld et al., 1997;Tokunaga et al., 2016), but also for surgeries (Prodromos et al., 1985). ...
Article
Full-text available
The assessment of knee or hip joint loading by external joint moments is mainly used to draw conclusions on clinical decision making. However, the correlation between internal and external loads has not been systematically analyzed. This systematic review aims, therefore, to clarify the relationship between external and internal joint loading measures during gait. A systematic database search was performed to identify appropriate studies for inclusion. In total, 4,554 articles were identified, while 17 articles were finally included in data extraction. External joint loading parameters were calculated using the inverse dynamics approach and internal joint loading parameters by musculoskeletal modeling or instrumented prosthesis. It was found that the medial and total knee joint contact forces as well as hip joint contact forces in the first half of stance can be well predicted using external joint moments in the frontal plane, which is further improved by including the sagittal joint moment. Worse correlations were found for the peak in the second half of stance as well as for internal lateral knee joint contact forces. The estimation of external joint moments is useful for a general statement about the peak in the first half of stance or for the maximal loading. Nevertheless, when investigating diseases as valgus malalignment, the estimation of lateral knee joint contact forces is necessary for clinical decision making because external joint moments could not predict the lateral knee joint loading sufficient enough. Dependent on the clinical question, either estimating the external joint moments by inverse dynamics or internal joint contact forces by musculoskeletal modeling should be used.
... However, there is no information on the contact pressure induced on the articular tibial cartilage after being treated with knee brace [4]. Also, no studies in the literature have quantified the external valgus moment that the mechanical valgus brace has to apply to the joint to completely unload the medial tibial cartilage [5]. ...
Conference Paper
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Knee osteoarthritis that prevalently occurs at the medial compartment is a progressive chronic disorder affecting the articular cartilage of the knee joint, and lead to loss of joint functionality. Valgus braces have been used as a treatment procedure to unload the medial compartment for patients with medial osteoarthritis. Valgus braces through the application of counteracting external valgus moment shift the load from medial compartment towards the lateral compartment. Previous biomechanical studies focused only on the changes in varus moments before and after wearing the brace. The objective of this study was to investigate the influence of opposing external valgus moment applied by knee braces on the lateral tibial cartilage contact conditions using a 3D finite element model of the knee joint. Finite element simulations were performed on the knee joint model without and with the application of opposing valgus moment to mimic the unbraced and braced conditions. Lateral tibial cartilage contact pressures and contact area, and tibial rotation (varus-valgus and internal-external) were estimated for the complete walking gait cycle. The opposing valgus moment increased the maximum contact pressure and contact area on the lateral tibial cartilage compared to the normal gait moment. A peak contact pressure of 8.2 MPa and maximum cartilage loaded area of 28% (loaded cartilage nodes) on the lateral cartilage with the application of external valgus moment were induced at 50% of the gait cycle. The results show that the use of opposing valgus moment may significantly increase the maximum contact pressures and contact area on the lateral tibial cartilage and increases the risk of articular cartilage damage on the lateral compartment.
... However, there is no information on the contact pressure induced on the articular tibial cartilage after being treated with knee brace [4]. Also, no studies in the literature have quantified the external valgus moment that the mechanical valgus brace has to apply to the joint to completely unload the medial tibial cartilage [5]. ...
... Reduction in KAM peak was statistically significant; however whether this equates to a clinically significant change remains unknown. There is currently no agreed level for a clinically significant change in KAM, with reductions following high tibial osteotomy of > 50% (Bhatnagar and Jenkyn 2010) compared to < 15% from knee unloader braces (Lindenfeld et al. 1997;Pollo et al. 2002). Increased training time is likely to be necessary for retention of the modifications and to facilitate continued reduction of KAM outside the lab. ...
Article
Background: Gait modifications can reduce the knee adduction moment, a representation of knee loading. Reduced loading may help to slow progression of medial knee osteoarthritis. We aimed to investigate the response of patients with medial knee osteoarthritis to direct feedback on the knee adduction moment as a method for modifying the gait pattern, before and after training with specific gait modifications. Methods: Forty patients with medial knee osteoarthritis underwent 3D gait analysis on an instrumented-treadmill, while receiving real-time feedback on the peak knee adduction moment. Patients were trained with three different modifications; toe-in, wider steps and medial thrust gait. The response to real-time feedback on the knee adduction moment was measured before and after training. To evaluate the short term retention effect, we measured the changes without feedback. We also evaluated the effects on the knee flexion moment and at the hip and ankle joints. Findings: With direct feedback on the knee adduction moment, patients were initially unable to reduce the knee adduction moment. After training with specific modifications, peak knee adduction moment was reduced by 14% in response to direct feedback. Without feedback a 9% reduction in peak knee adduction moment was maintained. Hip moments were not increased with modified gait, but small increases in ankle adduction moment and knee flexion moment were observed. Interpretation: Real-time biofeedback directly on the knee adduction moment is a promising option for encouraging gait modifications to reduce knee loading, however only when combined with specific instructions on how to modify the gait.
... Die Autoren schlussfolgern aus ihren Ergebnissen, dass die Schmerzreduktion unter Einsatz entlastender Orthesen möglicherweise als ein Resultat der reduzierten Aktivität der muskulären Kokontraktoren erklärt werden könnte. Entlastende Orthesen konnten in mehreren Arbeiten die Notwendigkeit einer chirurgischen Intervention erfolgreich verzögern [11, 17, 20] Während ein gewisser klinischer Nutzen entlastender Orthesen in der Behandlung der medialen Gonarthrose in verschiedenen Arbeiten gezeigt werden konnte, werden mögliche langfristige Erfolge in der Literatur kontrovers diskutiert. Giori [9] konnte zeigen, dass 61 % der Patienten, welche eine entlastende Orthese verschrieben bekommen hatten, diese auch nach 3 Jahren noch trugen. ...
Article
Hintergrund Valgisierende Orthesen stellen eine kostengünstige Alternative in der Behandlung der medialen Gonarthrose dar. Sie helfen zum einen in der präoperativen Diagnostik als Entscheidungshilfe, ob ein Patient aller Voraussicht nach von einer valgisierenden Osteotomie des Tibiakopfes profitiert. Darüber hinaus ist ein direkter klinischer Nutzen in Form einer Schmerzlinderung und Besserung der Kniegelenkfunktion in einigen Arbeiten gezeigt worden. Diskussion Die genauen Wirkungsmechanismen werden kontrovers diskutiert. Es wird eine Verringerung der mechanischen Last im medialen Kompartiment des Kniegelenks durch Verringerung des Varus, sowie eine Reduktion des gesteigerten Muskeltonus angenommen. Schlussfolgerung Ein langfristiger Nutzen der entlastenden Kniegelenkorthesen ist jedoch umstritten, da zum einen der degenerative Gelenkverschleiß fortschreitet, zum anderen aufgrund des oft fehlenden Tragekomforts der Orthesen die Bereitschaft zum Tragen der Orthese mit der Zeit abnimmt.
... The aim of current non-invasive treatments of pathological medial compartment knee loading is to reduce knee adduction moments and to stabilize knees with medial compartment OA or knees with varus alignment. These load-modifying techniques include bracing (Fantini Pagani, Potthast, & Brüggemann, 2010;Lindenfeld, Hewett, & Andriacchi, 1997;Pollo, Otis, Backus, Warren, & Wickiewicz, 2002), footwear modifications (Fisher, Mündermann, & Andriacchi, 2004;Kerrigan et al., 2002;Kerrigan, Karvosky, Lelas, & Riley, 2003) and gait training (Mündermann, Dyrby, Hurwitz, Sharma, & Andriacchi, 2004). Figure 8 shows an example of an orthosis model designed to reduce the knee adduction moment. ...
Article
Die Dissertation wurde am 22.06.2011 bei der Technischen Universität Mün-chen eingereicht und durch die Fakultät für Sport-und Gesundheitswissen-schaft am 20.12.2011 angenommen.
... Results showed that combination of the REBEL RELIEVER unloading knee brace with usual care was superior to usual care alone in terms of improvement of last 24h-pain, pain on motion, functional disability, disease evolution assessed by both the patient and the investigator, and clinical response rate after a 6-week treatment period. These results are consistent with previous published data suggesting that treatment with unloader braces improves pain and physical function 6,7,10,[17][18][19] . ...
Article
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Evidence is still inconclusive for the benefits of bracing in patients with knee osteoarthritis. To assess the effect of REBEL RELIEVER unloading knee brace in conservative treatment of knee osteoarthritis, a randomized controlled trial was conducted in 67 patients with symptomatic medial knee osteoarthritis, who randomly received 6-week treatment with either REBEL RELIVER unloading knee brace + usual care (Brace group, N = 32) or usual care alone (Control group, N = 35). Primary outcome was the global last 24h-pain relief (100-mm visual analogic scale [VAS]) at 6 weeks. Secondary endpoints included pain on motion (100-mm VAS), function (Lequesne index), safety and observance. At 6 weeks, mean [SD] last 24h-pain decreased significantly more in Brace group versus Control group (-41.35 [3.37] vs -15.37 [3.23], difference -25.98, 95% CI -41.64 to -10.33, P < 0.0001). Higher mean [SD] pain on motion decrease (-51.91 [3.49] vs -19.91 [3.34], difference -32.01, 95% CI -48.21 to -15.80, P < 0.0001) and better improvement of Lequesne index score (-5.8 [0.5] vs -2.3 [0.5], difference -3.5, 95% CI -5.0 to -2.0, P < 0.0001) were observed in Brace group. Safety and observance to the brace were excellent. The additive clinical benefit of wearing REBEL RELIEVER unloading knee brace was demonstrated in knee osteoarthritis patients.
... Gait analysis uses a motion capture systems and force plates to estimate the kinematics and kinetics of the patient during bracing treatment. Several studies reported the positive effect of braces on the frontal and sagittal plane kinetics [78][79][80][81], medial compartment load in vivo condition [82,83], tibiofemoral contact force, and lower limb alignment [84][85][86][87][88]. Kutzner et al. investigated the effect of three-point loading exerted by valgus braces on the medial compartment load in vivo by using strain gauges and reported that the medial load reduces during walking and stair ascension/descension [83,89]. The unloader braces with different valgus adjustments have a significant effect on the first and second peaks of KAM, the knee adduction angular impulse, improvement in knee pain and joint function [81, 85-87, 90, 91], and the knee adduction and flexion angle [87,88]. ...
Article
The paper aims to provide a state-of-the-art review of methods for evaluating the effectiveness and effect of unloader knee braces on the knee joint and discuss their limitations and future directions. Unloader braces are prescribed as a non-pharmacological conservative treatment option for patients with medial knee osteoarthritis to provide relief in terms of pain reduction, returning to regular physical activities, and enhancing the quality of life. Methods used to evaluate and monitor the effectiveness of these devices on patients’ health are categorized into three broad categories (perception-, biochemical-, and morphologybased), depending upon the process and tools used. The main focus of these methods is on the short-term clinical outcome (pain or unloading efficiency). There is a significant technical, research, and clinical literature gap in understanding the short- and long-term consequences of these braces on the tissues in the knee joint, including the cartilage and ligaments. Future research directions may complement existing methods with advanced quantitative imaging (morphological, biochemical, and molecular) and numerical simulation are discussed as they offer potential in assessing long-term and post-bracing effects on the knee joint. https://rdcu.be/bh63w Click this link to access full article (read-only)
... External KAM has routinely been considered as a surrogate measure to estimate and control TF joint internal load distribution [7,38] and as a marker for the medial OA [39]. Some findings however indicate otherwise [9,40,41]. In corroboration with our current predictions, Meyer et al. [9] and Walter et al. [8], using instrumented implants, have questioned an association between KAM and medial-lateral load partitioning. ...
Article
Background Osteoarthritis (OA) of the knee joint is a common disease accompanied by pain and impaired mobility. Despite some recent concerns on the lack of correlation between the medial load and the knee adduction moment (KAM), KAM is routinely considered as a surrogate measure of medial load and hence a marker where its reduction is the main focus of preventive and treatment interventions. Research question Determine the relative sensitivity of the tibiofemoral medial-lateral contact load partitioning to changes in the knee adduction angle (KAA) versus KAM. Methods Using a lower extremity hybrid musculoskeletal (MS) model driven by gait kinematics and kinetics, we compute here in asymptomatic subjects the sensitivity of the knee joint biomechanical response (muscle and ligament forces) in general and medial/lateral load partitioning in particular to the relative changes in the reported KAA versus changes in reported KAM (both by one standard deviation). Results As KAA increased (at constant KAM), so did the passive moment resistance of the knee joint which as a result and at all stance periods substantially reduced forces in lateral hamstrings while increasing those in medial hamstrings. At 25% and 75% stance as two highly loaded periods of gait, the drop in KAA (from + SD to –SD while at constant KAM) drastically reduced the medial contact force by 44% and 30% and the medial over lateral contact load and area ratios by 92% and 79% as well as 64% and 51%, respectively. In contrast, the equivalent alterations in KAM (by ± SD at constant KAA) had lower and less consistent effects (<7%) showing much smaller sensitivity to changes in KAM alone. Ligament forces altered at various stance periods with inconsistent trends; peak values of 418 N in the anterior cruciate ligament (90% carried by the posterolateral bundle) and 1056 N in the patellar tendon were computed both at 25% stance and minimum KAA. Significance These findings indicate a poor correlation between KAM and tibiofemoral load distribution suggesting instead that KAA and knee alignment should be in focus as the primary marker of knee joint load partitioning and associated prevention and treatment interventions.
... The reduction in the first peak KAM when wearing the biaxial AFO (26%) and lateral wedge insole (16%) was comparable to those previously reported in other studies [14,[27][28][29][30]. The reduction in fist peak KAM when using the lateral wedge insole was higher than those previously reported [13,14,31] (5-12% reduction). ...
Article
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Purpose This study aimed to compare a biaxial ankle-foot orthosis (AFO) with a lateral wedge insole in terms of the biomechanical and clinical outcomes in individuals with knee osteoarthritis. Materials and methods A cross-over randomized design was used where 31 individuals (25 females and six males, mean age of 52.19 ± 4.12 years) with knee osteoarthritis wore each intervention for two weeks with two weeks washout period. Three-dimensional kinematic and kinetic data and clinical outcomes were collected to evaluate the effects of each intervention on knee adduction moment (KAM), pain, stiffness, and function. Results Both orthoses significantly improved pain by 17 and 22%, function by 11 and 14%, the first peak KAM by 15.7 and 19.2%, the second peak KAM by 10.4 and 16.7%, and KAM impulse by 14.8 and 22.2%, respectively. However, the biaxial AFO significantly reduced the KAM and improved function compared to the lateral wedge insole (p < 0.01). Conclusions The results of this study have shown that both orthoses have a potential role in the conservative management of medial knee osteoarthritis. The biaxial AFO proved statistically better at improving function and KAM; though these differences do not seem to be clinically significant. • IMPLICATION FOR REHABILITATION • Orthotic interventions have been reported to be effective in the management of medial knee osteoarthritis. • Lateral wedge insole and biaxial ankle-foot orthosis (AFO) are effective in the improvement of pain, function, and knee adduction moment (KAM) in people with medial knee osteoarthritis. • The biaxial AFO, compared with lateral wedge insole, contributes to statistically more improvement of function and KAM. However, these differences do not seem to be clinically significant.
Article
Background: Knee adduction moment discrete features (peaks and impulses) are commonly reported in knee osteoarthritis gait studies, but they do not necessarily capture loading patterns. Principal component analysis extracts dynamic patterns, but can be difficult to interpret. This methodological study determined relationships between external knee adduction moment discrete measures and principal component analysis features, and examined whether amplitude-normalization methods influenced differences in those with knee osteoarthritis who progressed to surgery versus those that did not. Methods: 54 knee osteoarthritis patients had three-dimensional biomechanical measures assessed during walking. Knee adduction moments were calculated and non-normalized and amplitude-normalized waveforms using two common methods were calculated. Patterns were extracted using principal component analysis. Knee adduction moment peak and impulse were calculated. Correlation coefficients were determined between two knee adduction moment patterns extracted and peak and impulse. T-tests evaluated between-group differences. Findings: An overall magnitude pattern was correlated with peak (r=0.88-0.90, p<0.05) and impulse (r=0.93, p<0.05). A pattern capturing a difference between early and mid/late -stance knee adduction moment was significantly correlated with peak (r=0.27-0.40, p<0.05), but explained minimal variance. Between-group peak differences were only affected by amplitude-normalization method. Interpretation: Findings suggest that the overall magnitude knee adduction moment principal pattern does not provide unique information from peak and impulse measures. However, low correlations and minimal variance explained between the pattern capturing ability to unload the joint during mid-stance and the two discrete measures, suggests that this pattern captured a unique waveform feature.
Article
To evaluate the effectiveness of various orthotic treatments for patients with isolated medial compartment osteoarthritis. Prospective cohort study with sequential interventions. University-affiliated hospital, Hong Kong. From December 2010 to November 2011, 10 patients with medial knee osteoarthritis were referred by orthopaedic surgeons for orthotic treatment. All patients were sequentially treated with flat insole, lateral-wedged insole, lateral-wedged insole with subtalar strap, lateral-wedged insole with arch support, valgus knee brace, and valgus knee brace with lateral-wedged insole with arch support for 4 weeks with no treatment break. Three-dimensional gait analysis and questionnaires were completed after each orthotic treatment. The Western Ontario and McMaster Universities Arthritis Index (WOMAC), visual analogue scale scores, and peak and mean knee adduction moments. Compared with pretreatment, the lateral-wedged insole, lateral-wedged insole with arch support, and valgus knee brace groups demonstrated significant reductions in WOMAC pain subscore (19.1%, P=0.04; 18.2%, P=0.04; and 20.4%, P=0.02, respectively). The lateral-wedged insole with arch support group showed the greatest reduction in visual analogue scale score compared with pretreatment at 24.1% (P=0.004). Addition of a subtalar strap to lateral-wedged insoles (lateral-wedged insole with subtalar strap) did not produce significant benefit when compared with the lateral-wedged insole alone. The valgus knee brace with lateral-wedged insole with arch support group demonstrated an additive effect with a statistically significant reduction in total WOMAC score (-26.7%, P=0.01). Compliance with treatment for the isolated insole groups were all over 90%, but compliance for the valgus knee brace-associated groups was only around 50%. Gait analysis indicated statistically significant reductions in peak and mean knee adduction moments in all orthotic groups when compared with a flat insole. These results support the use of orthotic treatment for early medial compartment knee osteoarthritis.
Article
To determine the degree to which focally elevated tibiofemoral joint contact stress is reduced by using a frontal plane realigning brace. Fifteen volunteers (9 women) with unicompartmental tibiofemoral OA underwent weight-bearing radiographic imaging at 15-20° and 5-10° of knee flexion with and without an UnloaderOne knee brace. Discrete element analysis was used to estimate compartment-specific contact stress distributions. Paired t-tests were used to assess the differences in mean contact stress and contact stress distributions, comparing the braced and unbraced conditions. The mean±SD age was 56.1±6.4 years and BMI was 28.4±4.5kg/m(2) . Twelve of 15 participants were fit with braces set to unload the medial compartment. For the 15-20° condition, the mean contact stress in the compartment of interest did not significantly change (+0.08±0.35 MPa; p=0.410). Also at 5-10° flexion, the mean contact stress in the compartment of interest did not significantly change with use of the brace (+0.24±0.45 MPa; p=0.175). This is the first study of the effects of a frontal plane realignment brace on in vivo articular contact stress in native human knees. Using the off-the-shelf brace tested, there were no changes in compartmental tibiofemoral contact stress distributions at either 15-20° or 5-10° of knee flexion, revealing no redistribution of contact stress away from the compartment of interest. These findings indicate that the brace that was studied was ineffective for redistributing tibiofemoral contact stress. Further research is necessary to determine whether double-upright or customized frontal plane braces are effective in redistributing compartmental articular contact stress. This article is protected by copyright. All rights reserved. © 2015 American College of Rheumatology.
Article
The most common cause of disability in the United States is knee osteoarthritis (OA). This disease affects more than 27 million Americans commonly older than -40 years (Centers for Disease Control and Prevention [CDC], 2012). Osteoarthritis develops gradually over a period of years and results in the gradual deterioration of the hyaline cartilage that covers the articulating surfaces of the knee joint. In most people, the disease is idiopathic but can also be hereditary or the result of trauma, which causes pain, stiffness, limited range of motion, and localized swelling in the knee (Brandt and Slemenda. Osteoarthritis epidemiology, pathology and pathogenesis. In: Primer on the Rheumatic Diseases. 10th Ed. Atlanta, GA: Arthritis Foundation; 1993, p 18408). Knee OA cannot be cured, but there are interventions available to help manage the symptoms. An unloading knee orthosis is one course of action. The principle of the unloader knee brace is to create a varus or a valgus moment at the knee, creating additional space in the joint space, thus relieving pain caused by bone-on-bone contact and improving function within the knee for activities of daily living (ADLs) (Kirkley et al. J Bone Joint Surg 1999;81[4]:539-547. Sharma et al. JAMA 2001;286[2]:188-195). After extensive research, 42 custom and off-the-shelf OA knee braces are currently available within the United States for patients with varus and valgus gonarthrosis secondary to OA. Upon further examination, it was noted that only 15 of the 42 have evidence-based information to support their effectiveness in relieving symptoms common within the knee for an individual with a diagnosis of OA. The 15 braces are SofTec OA brace (Bauerfeind), Thruster 2/Dynamic Unloading Osteoarthritis (DUO) (Bledsoe), Legacy Thruster OA (Bledsoe), Fusion OA (Breg), Defiance OA (Donjoy), OA Adjuster (Donjoy), OA Nano (Donjoy), OAsys (Ossur), Unloader ADJ (Ossur), Unloader Express (Ossur), Unloader One (Ossur), Unloader Select (Ossur), Unloader Spirit (Ossur), Genu Arthro-Model 28K29/21 (Ottobock), and Bionicare Knee System (VQ OrthoCare). The purpose of this article was twofold. The first was to examine the pros and cons indicated within the evidence-based articles for each of the 15 OA knee braces currently on the market, and the second was to provide an updated picture for each of the 15 braces, as well as the manufacturer, description, indication(s), features, warranty, and approximate price list.
Chapter
Primary osteoarthritis is the most common disorder affecting the musculoskeletal system. Prevalence nears ubiquity over the age of 65 and therefore it has been considered a degenerative disease of the elderly1 Prevalence rates however, approximate 200–250/1000 population in patients 40 to 60 years of age. Many of these patients still desire an active athletic lifestyle.2 In patients with ligament or meniscal injury, as well as those patients with acute chondral injury, the curve representing the onset of secondary arthritis over time slopes upward earlier and steeper. Acute chondral injury has been reported by one study to occur in at least 5% of all arthroscopies performed on patients younger than 40, and it has been estimated that 900,000 Americans suffer acute articular cartilage injuries each year.3 Replacement of joint surfaces in younger, more active patients is fraught with danger and therefore many of these patients need more effective palliative treatments. Recent years have seen advances in the nonsurgical management options for painful arthritis and articular surface loss.
Chapter
The Smart Health paradigm has opened up immense possibilities for designing modern cyber physical/robotic systems for implementing data-, information- and knowledge-driven execution of healthcare decision making processes. From a rehabilitation context, a therapist seeks to better understand the bidirectional power interactions (motions and forces) arising from the complex interplay of the human neuro-musculo-skeletal system with its environment, with the ultimate intent of customizing and interactively modulating the associated dynamical patient behaviors. Many researchers have examined the benefits of quantitative sensing, computational analysis, data-driven decision-making and flexible-modulation of human behaviors through data-capture devices and wearable robotic systems. In recent times, many exemplary cyber-physical/robotic frameworks for home-based progressive rehabilitation have emerged. Immense flexibility ensues from a service-deployment perspective which need no longer be confined to the inpatient clinic. Numerous studies have shown that the most effective therapeutic results result from transferring rehabilitation process from clinic setting to patient's home. The scheduling logistics are significantly simplified (for the specialized equipment and personnel at the clinic) while patients now are afforded enhanced access in a self-directed manner. We will first survey existing clinic-based rehabilitaiton frameworks for upper limb motor rehabilitation (for stroke patients) and lower limb rehabilitation (for osteoarthritis patients). Subsequently, we examine several low-cost replacement COTS technologies and examine viability of their adaptation to support in-home therapeutic frameworks. We will evaluate these frameworks for both patient and provider benefits including: ease-of-use by all parties; modulating the intensity, duration and consistency of therapy; and logistics of monitoring and deployment for home-based use.
Article
In this chapter we review the basic principles, mechanisms of action and therapeutic indications of a number of Rehabilitation and Physical Medicine techniques commonly used for the management of patients with chondral lesions of the knee. The indications for a particular technique will depend on patient's characteristics, type of chondral lesion and type of treatment (non-operative or surgical). Finally, we also analyse the Rehabilitation and Physical Medicine techniques used after the surgical treatment of chondral injuries of the knee (drilling, debridement, mosaicplasty, autologous chondrocyte implantation), including non-weightbearing, movilisation modalities, muscle strengthening and stretching, proprioceptive re-training, mechanotherapy and electrotherapy.
Article
PURPOSE: This study investigated to correlation between foot and knee posture characteristics in knee osteoarthritis patients. METHODS: The subjects of this study were 103 patients with clinically and radiographically-confirmed knee osteoarthritis was investigated using the quadriceps angle (QA), distance of both knee (DBK), ankle dorsiflexion angle (ADA), navicular drop (ND). One-way ANOVA and Pearson`s correlation were used to investigate the correlation between foot and knee posture measurements. All of whom agreed to participate in the study. In order to assure the statistical significance of the results, we used for SPSS ver. 18.0 for windows. RESULTS: The results of this study were as follows : 1) There were statistically significant difference in the correlation between QA and DBK. 2) There were statistically significant difference in the correlation between DBK and ADA. CONCLUSION: According the results of this study, patients with osteoarthritis exhibit more genu varus knee posture. Moreover patients with osteoarthritis were not correlation between foot and knee Posture characteristics.
Article
Résumé La prise en charge non médicamenteuse devient une part non négligeable du traitement de la gonarthrose. Un de ces traitements consiste à réduire la contrainte physique appliquée au compartiment de l’articulation par le port d’orthèses du genou ou du pied. Le but de cette mise au point est de rapporter les différents types d’orthèses – genou et pied – à notre disposition dans la gonarthrose fémoro-tibiale – médiale ou latérale – et fémoro-patellaire. Nous rapporterons ensuite quelques études et méta-analyses sur le port d’orthèses dans les gonarthroses. Un nouveau type d’orthèse associant la distraction (écartement) et rotation latérale sera abordé.
Article
Unicompartmental knee osteoarthritis (UKOA) is a complex issue that is estimated to affect roughly 28% of patients with knee OA, and can result in severe cartilage degeneration, meniscus deficiency, and concomitant varus or valgus malalignment. This malalignment results in abnormally high joint reaction forces in the affected compartment, which can elicit pain, cause dysfunction, and exacerbate joint degradation. For more than two decades, the use of knee unloader braces has been advocated as a cost-effective option for symptomatic management of UKOA. During bipedal ambulation with a normal lower extremity mechanical axis, ground reaction forces create a knee adduction moment (KAM) such that the medial compartment of the knee experiences approximately 60% of joint loading and the lateral compartment experiences approximately 40% of joint loading. UKOA disrupts the mechanical axis, altering KAM and joint loading and causing pain, dysfunction, and disease progression. In theory, knee unloader braces were designed to mitigate the symptoms of UKOA by normalizing KAM via shifts in the lever arms about the knee. However, studies vary, and suggest that push-mechanism knee unloaders do not consistently provide significant biomechanical benefits for medial or lateral UKOA. Current evidence suggests that pull-mechanism unloaders may be more effective, though contrasting data have also been reported, such that further validation is necessary. The purpose of our study was to synthesize current best evidence for use of knee unloader braces for management of UKOA to suggest evidence-based best practices as well as gaps in knowledge to target for future studies. Unloader bracing for patients with UKOA appears to be a cost-effective treatment option for patients with medial UKOA who have insurance coverage. Pull-mechanism unloader bracing should be considered in conjunction with other nonoperative management therapies for those who are willing to adhere to consistent brace use for weight-bearing activities.
Chapter
The treatment of the young ACL deficient patients with an osteoarthritic knee has been a great dilemma for orthopaedic surgeons. The treatment options in the past have been limited and the literature gave us little direction. Patients were granted analgesics, anti-inflammatories, physical therapy and were braced until they were old enough for total knee replacement. However in the last eight years surprisingly good results have been reported in these patients with anterior cruciate reconstruction, high tibial osteotomies, meniscal allografts and combined procedures.
Article
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Introduction: Unloader braces are non-surgical treatment options for patients with unicompartmental knee osteoarthritis (OA). However, many patients do not adhere to brace treatment because of complications related to discomfort and poor fit. An alternative to knee bracing is an ankle-foot orthosis (AFO) with a lever arm that presses the lower leg into valgus or varus. The aim of this study is to evaluate the clinical benefits of this AFO for patients with unicompartmental knee OA. Materials and methods: Twenty-three patients with knee OA were enrolled in this observational study. The primary clinical outcome measure was the Western Ontario and McMasters Universities Arthritis Index (WOMAC) total score. Secondary outcome measures included WOMAC subscores, visual analogue pain scale, activity restriction and complication rate. Clinical scores were collected at start and 3, 6, 9, and 12 months after enrollment. Statistical evaluation was performed using the Student's t test. Results: Of the patients enrolled, 83 % suffered from medial compartment OA. Most patients had Grade II OA according to the Kellgren and Lawrence classification. WOMAC total score, both subscores and visual analogue pain scale were significantly improved over time. Patients also noted a reduction in restrictions to activities of daily living and sport-related activities while using the AFO. No patients discontinued orthosis use because of adverse effects. Two types of complications were noted: discomfort or light pressure sores around the ankle (7 patients), and wear and tear of the shoe in which the AFO was worn (14 patients). Conclusions: This observational study suggests that this AFO is effective at significantly reducing pain and stiffness as well as improving the physical function of patients with mild to moderate unicompartmental osteoarthritis of the knee.
Article
Background: Evidence that knee braces used for the treatment of osteoarthritis mediate pain relief and improve function by unloading the joint (increasing the joint separation) remains inconclusive. Alternatively, valgus-producing braces may mediate pain relief by mechanically stabilizing the joint and reducing muscle cocontractions and joint compression. In this study, therefore, we sought to examine the degree to which so-called unloader braces control knee instability and influence muscle cocontractions during gait. Methods: Sixteen subjects with radiographic evidence of knee malalignment and medial compartment osteoarthritis were recruited and fitted with a custom Generation II Unloader brace. Gait analysis was performed without use of the brace and with the brace in neutral alignment and in 4 degrees of valgus alignment. A two-week washout period separated the brace conditions. Muscle cocontraction indices were derived for agonist and antagonist muscle pairings. Pain, instability, and functional status were obtained with use of self-reported questionnaires, and the results were compared. Results: The scores for pain, function, and stability were worst when the knee was unsupported (the baseline and washout conditions). At baseline, nine of the sixteen patients reported knee instability and five of the nine complained that it affected their activities of daily living. Poor knee stability was found to be correlated with low ratings for the activities of daily living, quality of life, and global knee function and with increased pain and symptoms. Knee function and stability scored best with the brace in the neutral setting compared with the brace in the valgus setting. The cocontraction of the vastus lateralis-lateral hamstrings was significantly reduced from baseline in both the neutral (p = 0.014) and valgus conditions (p = 0.023), and the cocontraction of the vastus medialis-medial hamstrings was significantly reduced with the valgus setting (p = 0.068), as a result of bracing. Patients with greater varus alignment had greater decreases in vastus lateralis-lateral hamstring muscle cocontraction. Conclusions: When knees with medial compartment osteoarthritis are braced, neutral alignment performs as well as or better than valgus alignment in reducing pain, disability, muscle cocontraction, and knee adduction excursions. Pain relief may result from diminished muscle cocontractions rather than from so-called medial compartment unloading.
Article
Die mediale Kniegelenkarthrose ist eine der häufigsten Erkrankungen bei Personen über 55 Jahren. Die eingeschränkte Mobilität und Schmerzsituation beeinträchtigen das tägliche Leben. Neben den operativen gibt es auch konservative Maßnahmen, die zu einer Schmerzreduktion und Belastungsnormalisierung führen können. Dazu zählen aktive Maßnahmen wie die Modifikation des Gangbilds und Muskelkräftigung. Durch die Modifikation des Gangbilds lässt sich die Belastungssituation im Gehen reduzieren. Nachgewiesen wird diese Belastungsreduktion mithilfe einer dreidimensionalen Ganganalyse. Der primäre Zielparameter ist dabei das externe Adduktionsmoment. Modifikationen, die die Belastungssituation positiv beeinflussen sind vermehrte Seitneigung zur Standbeinseite, vermehrte Fußaußenrotation oder vermehrte Oberschenkelinnenrotation. Passive Maßnahmen, wie Kniegelenksorthesen oder Schuhranderhöhungen, können ebenfalls zu einer Reduktion des externen Adduktionsmoments führen. In Studien wurde nachgewiesen, dass die Maßnahmen nicht nur das Adduktionsmoment, sondern auch subjektiv das Schmerzempfinden verringern. Konservative Maßnahmen können eine Belastungsreduktion im Kniegelenk bewirken und somit die Lebensqualität insgesamt etwas steigern.
Article
Patients with knee osteoarthritis (KOA) usually experience pain in the medial compartment of their knee which accompany varus postures. This causes much larger lateral-side foot pressure than that of the medial side which may lead to functional limitation in their daily life. Reducing knee loading during gait could help patients with KOA alleviate pain and improve walking functions. In this study, a prototype for a new pneumatic knee orthosis (PKO) is developed to support the knee by increasing the pneumatic pressure of the PKO during the stance period of walking using foot pressure feedback in real time. Force-sensing resistor sensors in the PKO were used to detect the gait phase and monitor the foot pressures in real time. To investigate the feasibility of the system, walking tests on a treadmill were performed at 2 km/h and 3 km/h by healthy subjects. The results show that the developed PKO can reduce lateral-side foot pressure during stance phase. The PKO in this study could be used as a research tool to investigate the relationship between foot pressure and knee loading as well as therapeutic purposes to reduce medial compartment loading in the knee.
Article
Knee-pain due to osteoarthritis (OA) is often located in the medial compartment. Concomitant varus malalignment is associated with the development of knee OA and its progression. Unloader-braces and ankle foot orthoses are devices which were invented to support the knee joint to relieve pain and to improve patients’ quality of life. Multiple case series showed positive effects when using them, especially in low-grade arthritis and mild varus malalignment. They can be used on a daily basis as an inherent part of nonsurgical treatment of knee OA or be worn activity-dependent. The brace test simulates the effect of a valgus osteotomy. It is a useful tool to test the unloading effect before indicating this operation.
Article
Purpose: Unicompartmental knee osteoarthritis (OA) is often treated with the prescription of an unloading knee brace to decrease pain and stiffness. Braces have been shown to improve the quality of life by applying an external moment to offset increased compressive tibiofemoral contact loads, but evidence regarding mechanical efficacy at the joint is controversial. Thus, the purpose of this study was to review the current state of unloading braces on knee mechanics, clinical impact, and long-term disease progression. Methods: A literature search was performed through the PubMed MEDLINE database for the search terms "osteoarthritis," "knee," "brace," and derivatives of the keyword "unload." Articles published since January 1, 1980 were reviewed for their relevance. Evidence for the effectiveness of unloading braces for disease management both biomechanically and clinically was considered. Results: While significant research has been done to show improvement in OA symptoms with the use of an unloading brace, current literature suggests a debate regarding the effectiveness of these braces for biomechanical change. Clinical findings reveal overall improvements in parameters such as pain, instability, and quality of life. Conclusion: Although clinical evidence supports brace use to improve pain and functional ability, current biomechanical evidence suggests that unloading of the affected knee compartment does not significantly hinder disease progression. LEVEL OF EVIDENCE: III.
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Thirty-two patients with an ACL-deficient knee and lower limb varus alignment and 16 healthy controls were analyzed during level walking using a force-plate and optoelectronic system. The forces and moments of the lower limb and knee joint were measured and knee joint loads and ligament tensile forces were cal culated using a mathematical model. The majority of patients (20 of 32) had an abnormally high adduction moment at the affected knee. The ad duction moment showed a statistically significant cor relation to high medial tibiofemoral compartment loads and high lateral soft tissue forces, but not to the degree of varus alignment on standing roentgenograms. Fif teen of 32 knees had abnormally high lateral soft tissue forces. We interpreted these gait findings as indicative of a medial shift in the center of maximal joint pressure and an increase in lateral soft tissue forces to achieve coronal plane stability. Further, there is the likelihood of separation of the lateral tibiofemoral joint and "con dylar lift-off" during periods of the stance phase. If this occurs, all of the load-bearing forces would shift to the medial tibiofemoral joint and relatively large tensile forces would occur in the lateral soft tissue restraints. The flexion moment, as related to the quadriceps muscle force, was significantly lower than the control knees in 40% of the involved knees, and the extension moment, as related to the hamstring muscle force, was significantly higher in 50% of the involved knees. We interpret this finding as a gait adaptation tending to diminish quadriceps muscle activity and enhance ham string muscle activity to provide dynamic anteroposte rior stability of the knee joint. The fundamental assumption of this paper is that any combination of conditions leading to higher medial joint forces is associated with factors leading to more rapid degeneration of the medial compartment in patients with ACL deficiency, varus deformity, and lax lateral ligaments.
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Although there are several different classification systems for the description of articular cartilage damage, each has certain limitations and deficiencies which can lead to confusion. We are proposing a new system which describes articular cartilage abnormalities in simple terms. It is based on four separate and distinct variables: the description of the articular surface, the extent (depth) of involvement, the diameter of the lesion, and the location of the lesion. Although somewhat qualitative and subjective, the system enables the surgeon to record observed articular cartilage changes. We have used this grading as part of our overall knee rating system and have found it helpful in comparing treatment results between our different studies. For research purposes, a point scaling system facilitates computerization and statistical analysis of the data.
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We studied the cases of twenty-one patients with high tibial osteotomy in order to determine the relationship between knee-joint loading during gait and clinical outcome. The patients were tested before surgery, one year after surgery, and again at an average of 3.2 years after surgery. An age-matched group of fifteen control subjects was also studied. The results of this study indicate that certain characteristics of preoperative walking are associated with postoperative clinical results. In particular, the moment tending to adduct the knee joint during walking preoperatively was predictive of postoperative clinical results. The patients were classified into a high adduction-moment group and a low adduction-moment group according to the magnitude of the knee-adduction moment. The adduction moment was reduced in both groups after high tibial osteotomy. However, the average postoperative adduction moments in the low adduction-moment group were still significantly lower than those in the high adduction-moment group. The two groups were indistinguishable on the basis of preoperative knee score, initial varus deformity, immediate postoperative correction, age, and weight. However, at an average 3.2-year follow-up, patients with low preoperative adduction moments had substantially better clinical results than did patients with high adduction moments. The low adduction-moment group had 100 per cent excellent or good clinical results, while only 50 per cent of the patients in the high adduction-moment group had an excellent or good result. Furthermore, there was a significant recurrence of varus deformity in the patients in the high adduction-moment group.(ABSTRACT TRUNCATED AT 250 WORDS)
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We assessed short-term treatment results of younger patients with varus malalignment and chronic anterior cruciate ligament deficiency. Forty-one patients (mean, 32 years; range, 16 to 47) underwent a high tibial osteotomy. Because of giving way symptoms, 14 also had a lateral iliotibial band extraarticular procedure at the time of the osteotomy and 16 had an intraarticular anterior cruciate ligament allograft reconstruction after the osteotomy. All returned for followup (mean, 58 months; range, 23 to 86), which included KT-1000 arthrometer testing and evaluation by our knee rating system. Statistically significant ( P < 0.05) improvements were found in the mean overall rating scores for pain, swell ing, and giving way. Preoperatively, 30 (73%) had pain with activities of daily living or with any sports activity; 11 (27%) could perform only light sports activities with out pain. At followup, 32 patients (78%) had no pain with activities of daily living or light sports. Ten of 15 patients with advanced medial tibiofemoral arthrosis (subchondral bone exposure) had significant improvements in symptoms. Patient satisfaction was high: 88% stated they would undergo the procedure again and 78% felt their knee condition was improved. Patients who had the allograft reconstruction had significantly lower ( P < 0.05) anterior-posterior dis placements at followup than those who had the extraar ticular procedure. We concluded that osteotomy should be performed early in the disease process for younger athletes who experience symptoms with activity. It may be unrealis tic, however, to expect continuation of sports beyond light recreational, given the joint arthrosis that is usually present and the high in vivo joint loadings with athletes. Anterior cruciate ligament reconstruction should be considered when giving way previously occurred and the patient plans to resume athletics. However, patients with advanced arthrosis can avoid anterior cruciate ligament surgery by reducing athletic activities.
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A method of close range three-dimensional object location reconstruction from planar image data, useful for studies of human motion, is described. The method uses calibration points placed over the entire field of observation. This method does not require the assumption of a theoretically perfect camera, and is particularly useful when large amounts of optical and electrical distortion are present. The fundamental assumption of the method is that polynomial functions exist that can account for distortions within acceptable error. Random noise is reduced by low-pass filtering. The large amounts of data, and the number of calculations required to reduce it, make computer acquisition and processing a virtual necessity. The accuracy of the method over a 120 by 240-cm viewing area was evaluated in a calibration study. The accuracy of the system depends on the number of calibration points. When 29 calibration points were used, the average resolution is 1 part in 500. The average accuracy resolves the position of an object point within the radius of the LED's used to locate targets. This resolution was found adequate for studies of human gait kinematics.
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A double crossover study was designed and carried out on 39 patients to test the efficacy of valgus bracing using a GII brace in patients with medial gonarthrosis. Two brace designs were studied-one with a medial and one with a lateral hinge. The double crossover technique involved evaluating each patient under conditions of no brace, brace in neutral, and brace in valgus, each for a period of 6 weeks. Pain and function were recorded by subjects on diary forms daily and at the end of each week. Standing posterior-anterior radiographs were done on all patients under conditions of weight bearing, nonweight bearing, without brace, and with brace in valgus. Statistical analysis using repeated measures analysis of variance showed statistically significant pain relief compared to baseline with both a lateral hinge in valgus (p = 0.02) and a medial hinge in valgus (p < 0.0001). No significant change in function was found and no significant radiographic evidence of change in femoral-tibial angle or joint space alteration was demonstrated. Seventy-four percent of patients purchased their brace at the end of the study. Follow-up at an average 20 months after the study showed 58% of the patients with a lateral hinge and 93% of the patients with a medial hinge were still using their braces as the principal form of therapy. Valgus bracing using a GII brace, especially with a medial hinge, can be a useful treatment modality for reducing pain in the patient with medial gonarthrosis to replace or delay surgery. (C) Lippincott-Raven Publishers.
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From this study of 213 knees it appears that 61.8% of the patients rated themselves as having less pain than before osteotomy even after 10 years from the time of surgery. Functionally, 64.7% were better. Rarely did a patient believe that his pain was worse than it was preoperatively, even up to 10 years after the surgery; nor did any patient believe that his functional status was compromised further by the operation. The conclusions drawn from the most recent study are the following. Upper tibial osteotomy for gonarthrosis and varus deformity relieves pain and restores function in more than 60% of the patients, even 10 years after the operation. The major complication is recurrence of deformity, in part, at least, the cause of recurring pain. It can be minimized by achieving at least 7 degrees of valgus axial alignment (up to 10 degrees is allowable), and by excluding from operation knees with bicompartmental involvement.
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Gait observations of normal subjects and patients with knee disabilities are presented. Time-distance measurements and ground reaction force parameters are reported in relation to walking speed. Regression analysis is used to establish simple functional relations between ground reaction force amplitudes and walking speed.It is shown that basic time distance measurements observed over a range of walking speeds can be useful indicators of gait abnormalities associated with knee disabilities. For example, clinical improvement after treatment is found to be consistent with changes in these gait parameters. These results indicate the usefulness and importance of considering gait measurements in relation to walking speed when attempting to classify gait abnormalities.
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Using an instrumented cadaver lower extremity, the forces in the quadriceps, patella, and tibia during flexed-knee stance were measured and the calculated and experimental data were found to correlate with an average discrepancy of 6 per cent. The quadriceps force required to stabilize the knee was 75 per cent of the load on the femoral head at 15 degrees of knee flexion, 210 per cent at 30 degrees, and 410 per cent at 60 degrees. Stresses at the tibiofemoral and patellofemoral joint surfaces increased in similar fashion. The quadriceps force was equivalent to 20 per cent of average maximum quadriceps strength at 15 degrees and to 50 per cent at 30 degrees, as determined from torque tests on five normal subjects.
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The gait of normal subjects and patients with varus deformities at the knee was studied by analyzing the interaction between the dynamic (muscular) and passive (ligamentous) restraints affecting lateral stability of the knee. A statistically determinant model predicted that the midstance-phase adducting moment during normal gait would cause lateral knee joint opening if either antagonistic muscle force and/or pretension in the lateral soft tissues were not present at the knee. The patient group tended to compensate for a high midstance-phase adducting moment by walking with a style of gait that demanded more muscle force (greater flexion-extension moments). This walking style reduced the chance of lateral joint opening. It can be speculated that this style of gait would help to maintain equilibrium at the knee. The higher muscle force would aid in resisting the adducting moment, keeping the joint closed laterally and thus increasing the stability of the knee.
Article
The current study describes the influence of the passage of time on the original findings. The mechanisms used by some patients to reduce loading at the knee (adduction moment) also were analyzed. We evaluated the gait of twenty-seven patients (thirty-two knees) who had had a proximal tibial osteotomy for a varus gonarthrosis. Twenty-four patients (twenty-eight knees) returned for follow-up at three to 8.9 years after the osteotomy. This is a follow-up to our original study (Prodromos et al.), which described a relationship between the magnitude of the adduction moment at the knee during walking and the outcome of proximal tibial osteotomy. The patients were divided into low and high adduction-moment groups on the basis of the magnitude of the adduction moment at the knee as measured preoperatively during walking. All fourteen patients in the low adduction-moment group and nine of the fourteen patients in the high adduction-moment group had a good or excellent result. The varus deformity recurred in ten patients in the high adduction-moment group and in three patients in the low adduction-moment group. All of the results degenerated over time. The adaptive mechanism that was used to lower the adduction moment during gait included shortening the stride and toeing-out. The significant correlation between the magnitudes of the inversion moment at the ankle and the adduction moment at the knee suggested that the toe-out gait reduced the adduction moment at the knee.(ABSTRACT TRUNCATED AT 250 WORDS)
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Arthroscopic debridement is a valuable alternative procedure in the management of osteoarthritis of the knee joint. Although palliative in nature, in many instances it yields permanent relief in the low-demand knee of the elderly. It is especially valuable in young individuals who have not yet reached the ideal age for reconstruction. The procedure is a demanding one, requiring considerable arthroscopic skills. Sclerotic lesions, synovitis, loose bodies, osteophytes, chondromalacia, and degenerative tears of menisci are encountered often in various combinations and must be addressed judiciously and completely. The procedure simplifies rehabilitation, and the risk/benefit ratio is very favorable.
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The basic parameters of gait were studied in 14 patients with medial gonarthrosis before and eight to 12 months after high tibial osteotomy. In seven patients, the osteotomy was fixed with staples. The patient was placed in plaster immobilization for six weeks and weight bearing was allowed after ten weeks. In the other seven patients, the osteotomy was fixed with a T-plate, and immediate joint motion and weight bearing were allowed after six weeks. There was no difference in any parameter of gait among patients treated with the two techniques. For all patients, the mean maximal velocity preoperatively was 65% of that of normal people, with only a slight, nonsignificant increase at the follow-up examination. An additional indication of insufficient rehabilitation was the decrease in stride length at constant maximal velocity at the follow-up evaluation. Positive correlations were found between stride length and muscle torque in the thigh. Positive correlations were also found between a subjective score and maximal velocity. Simple tests of velocity, stride length, and stride frequency are recommended as an easy and decisive method of follow-up evaluation.
Article
We evaluated the results in eighty-three patients (ninety-five knees) who had had a high tibial osteotomy for either unicompartmental osteoarthritis or osteonecrosis. The operations were performed between 1965 and 1976. The mean length of follow-up was 8.9 years (range, five to fifteen years). The early results were promising: at two years 97 per cent and at five years 85 per cent of the knees had either an excellent or a good result. At subsequent follow-up, however, only sixty knees (63 per cent) had an excellent or good result, and in the remainder recurrent pain had developed. Twenty-two knees (23 per cent) had been revised to a total knee arthroplasty because of pain. The alignment obtained by the osteotomy was not as important in determining the long-term result as we had previously believed. Although recurrent varus deformity was observed in more than one-quarter of the knees, it was not necessarily associated with an unsatisfactory result. The passage of time was the most important factor in determining the result, as only fifteen (37 per cent) of the knees that had been followed for more than nine years were pain-free. We now believe that total knee arthroplasty is a more suitable operation for patients who are more than sixty years old and that high tibial osteotomy should be reserved for patients who have a strenuous occupation or who wish to continue to participate in sports activities.
Article
In this study, we determined which ligaments and capsular structures resist medial and lateral opening of the joint space in cadaver knees during clinical testing for straight medial and lateral laxity. Restraining function was recorded as the per cent contribution of each structure in resisting the force applied by the examiner. In sixteen cadaver knees tested at 5 and 25 degrees of flexion from full hyperextension, the collateral ligaments provided the primary restraint (greater than one-half of the total) at both flexion angles. At 5 degrees, the posterior part of the capsule and the cruciate ligaments were important secondary restraints. As flexion increased, the posterior part of the capsule became slack, causing a marked decrease in its restraining action. The middle one-third of the medial and lateral halves of the capsule, traditionally considered important, provided little restraining force. The iliotibial tract and the popliteus musculotendinous unit provided little passive restraint. However, a force applied to either the iliotibial band or the biceps tendon, to simulate muscle tension, produced an additional restraint that in vivo presumably would protect the lateral ligaments and capsule. Using an instrumented kinematic chain to determined the three-dimensional joint motion in six knees during testing for straight varus-valgus laxity by the maneuvers used clinically, we found that axial rotation of the tibia occurred that may be misinterpreted as medial or lateral joint opening. When just the medial or the lateral collateral ligament (the primary restraints) was sectioned, only a three to five-millimeter increase in joint opening occurred. This increase was small because only low forces were applied during the clinical examination and the secondary restraints blocked further opening even though the primary restraint was disrupted. Near full extension, the secondary restraints almost completely blocked opening of the joint after sectioning of the collateral ligaments. Clinical relevance: With knowledge of the hierarchy of restraining moments contributed by the medial and lateral ligament and capsular structures and an appreciation of the rotatory movements of the knee that may occur during test for straight varus-valgus laxity, both diagnosis and treatment can be more precise.
Article
Anatomic and mechanical factors that affect loading in the knee joint can contribute to pathologic changes seen at the knee in degenerative joint disease and should be considered in treatment planning. The objectives of this study were to quantify the relationships between the alignment of the bones of the lower extremity, foot progression angle, and knee adduction moment, and to determine the reliability of our gait measurements. Gait analysis and complete radiographic evaluation of the lower extremity were performed on 11 healthy subjects. The gait measurements were recorded with an optoelectronic digitizer and a multi-component force plate. The subjects who had radiographic measurements indicative of varus alignment of the lower extremity had statistically higher peaks in knee adduction moment in early stance. Conversely, those with valgus alignment of the lower extremity had statistically lower peaks in knee adduction moment in early stance. The subjects who had a large toe-out angle and low ankle inversion moment peaks in late stance had significantly lower peaks in knee adduction moment in late stance. These significant (low to moderate) correlations suggest that the limbs with more valgus alignment and those with a toe-out gait exhibited a reduced peak adduction moment at the knee. To verify the reproducibility of the data, gait analysis testing was performed on each lower limb on 2 separate days for each subject. Analysis of variance showed that there was no significant difference between test limbs or test days for each subject. Our results suggest that the alignment of the lower limb and the foot progression angle, which can be readily measured in a clinical setting, can serve as predictors of knee joint loading in healthy individuals. These findings may have important implications for both surgical and nonsurgical treatment of abnormalities of the knee joint.
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Human locomotion is a phenomenon of the most extraordinary complexity in which so great are the multitude of individual motions occurring simultaneously in the three planes of space that analysis is difficult without some unifying principle. The adoption of the concept that fundamentally locomotion is the translation of the center of gravity through space along a pathway requiring the least expenditure of energy supplies the necessary unifying principle which permits of qualitative analysis in terms of the essential determinants of gait. The six major determinants are pelvic rotation, pelvic tilt, knee and hip flexion, knee and ankle interaction, and lateral pelvic displacement. The serial observations of irregularities in these determinants provides insight into individual variation and a dynamic assessment of pathological gait. Pathological gait may be viewed as an attempt to preserve as low a level of energy consumption as possible by exaggerations of the motions at unaffected levels. Compensation is reasonably effective with the loss of one determinant of which that at the knee is the most costly. Loss of two determinants makes effective compensation impossible and the cost of locomotion in terms of energy is increased threefold with an inevitable drain upon the body economy.