No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Facteurs prédictifs de la qualité du contrôle postural et de sa compensation dans les pathologies traumatiques et dégénératives du genou
Abstract
La rupture du ligament croisé antérieur du genou est très fréquente, notamment dans les activités qui impliquent des contraintes en rotation. Une dégénérescence du cartilage articulaire du genou peut par la suite engendrer une arthrose. Le but de cette étude était d’une part dans les pathologies traumatiques et d’autre part dans les pathologies dégénératives, atteignant cette articulation, d’analyser les facteurs prédictifs du contrôle postural et de la récupération fonctionnelle. Les effets d’une rééducation innovante combinant une rééducation conventionnelle réduite avec une rééducation en milieu aquatique ont été comparés à ceux d’une rééducation conventionnelle définie par la Haute Autorité de Santé, sur la cinétique de récupération des compétences proprioceptives et sur l’amélioration fonctionnelle. Le contrôle postural par posturographie et la motricité au moyen de tests cliniques ont été quantifiés chez 67 patients ayant présenté une rupture du ligament croisé antérieur, avant intervention et jusqu’à six mois après intervention chirurgicale. Les effets des paramètres météorologiques sur le contrôle postural et la douleur dans la gonarthrose ont été évalués chez 113 patients, par posturographie et échelle de douleur. Pour une même qualité globale du contrôle postural six mois après ligamentoplastie du genou, les patients ayant suivi le protocole de rééducation innovant utilisaient davantage la somesthésie que ceux ayant suivi une rééducation conventionnelle, qui devaient recourir plus à un mécanisme de compensation. La proprioception était améliorée deux mois après l’intervention chirurgicale par rapport à l’évaluation pré-opératoire chez les patients ayant suivi le protocole innovant. La force musculaire était plus importante chez les patients ayant suivi le protocole de rééducation innovant un mois, deux mois et six mois après intervention. Un mois après l’intervention, la distance de marche parcourue était plus importante chez les patients ayant suivi la rééducation innovante que chez les patients ayant suivi la rééducation conventionnelle. Chez les patients présentant une gonarthrose, une dégradation du contrôle postural était observée lorsque la pression atmosphérique et l’humidité maximale diminuaient au cours de la matinée et lorsque la pression atmosphérique diminuait au cours de la journée. L’augmentation de la douleur était corrélée avec l’augmentation de la température sur la matinée et avec l’augmentation de la température et de l’humidité sur la journée. L’environnement dans lequel évolue le sujet (ex : milieu aquatique, ambiance climatique) a donc une influence sur la performance du contrôle postural. Une meilleure prise en charge en rééducation post-ligamentoplastie du genou permettrait de limiter la nécessité de compensation sur le membre contralatéral par une meilleure utilisation de la somesthésie et ainsi prévenir la survenue de l’arthrose et d’une rupture ligamentaire contralatérale. Ceci permettrait de limiter les coûts socio-professionnels
ResearchGate has not been able to resolve any citations for this publication.
Background
Instability of the knee, related to anterior cruciate ligament injury, is treated by surgical reconstruction. During recovery, a loss of proprioceptive input can have a significant impact. Few studies have evaluated the benefits of rehabilitation of the knee in aquatic environment on functional outcomes.Objective
This study aimed to compare an innovative rehabilitation protocol combining reduced conventional rehabilitation with aquatic rehabilitation, with a conventional rehabilitation, according to the National French Health Authority, in terms of kinetics, development of proprioceptive skills, and functional improvement of the knee.Methods67 patients, who were amateur or professional athletes, were randomized into two groups: 35 patients followed the conventional rehabilitation protocol (Gr1) and 32 patients followed the innovative rehabilitation protocol (Gr2). Patients were evaluated before surgery, and at 2 weeks, 1, 2, and 6 months after surgery using posturography, and evaluation of muscular strength, walking performance and proprioception. This study is multicenter, prospective, randomized, and controlled with a group of patients following conventional rehabilitation (level of evidence I).ResultsFor the same quality of postural control, Gr2 relied more on somesthesia than Gr1 at 6 months. The affected side had an impact on postural control and in particular on the preoperative lateralization, at 2 weeks and at 1 month. Lateralization depended on the affected knee, with less important lateralization in Gr2 preoperatively and at 1 month. The quadriceps muscular strength was higher in Gr2 than in Gr1 at 2 and 6 months and muscle strength of the external hamstring was greater in Gr2 than in Gr1 at 6 months. The isokinetic test showed a greater quadriceps muscular strength in Gr2. Gr2 showed a greater walking distance than Gr1 at one month. Gr2 showed an improvement in the proprioceptive capacities of the operated limb in flexion for the first 2 months.Conclusion
The effectiveness of the innovative rehabilitation program permits faster recovery, allowing for an earlier return to social, sporting, and professional activities. Faster retrieval of knee function following aquatic rehabilitation would prevent both short-term risk of lesions of the contralateral limb due to overcompensation and long-term risk of surgery due to osteoarthritis.Registration of clinical trialsNCT02225613.
Objective
This study aimed to support the potential protective role of anterior cruciate ligament (ACL) reconstruction against the development of osteoarthritis (OA).
Methods
In this retrospective cohort study, the long-term results of ACL reconstruction in Taiwan were evaluated based on data from the National Health Insurance Research Database (NHIRD). In total, 8,769 eligible cases were included from 11,921 ACL-injured patients. The cumulative incidence rates of OA and total knee replacement (TKR) were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of OA.
Results
There was a lower cumulative incidence of OA among ACL-reconstructed patients (271, 33.1%) than among non-reconstructed patients (1,874, 40.3%; p < 0.001). Patients who underwent ACL reconstruction had a lower cumulative incidence of TKR during the follow-up period (0.6%) than the non-reconstructed patients (4.6%, p < 0.001). After adjusting for covariates, ACL-injured patients who underwent reconstruction within one month after ACL injury showed a significantly lower risk of OA than those who never underwent reconstruction (adjusted HR = 0.83, 95% CI = 0.69–0.99).
Conclusions
These results indicate that ACL reconstruction might not provide complete protection from OA development after traumatic knee injury but does yield a lower cumulative incidence of OA development and TKR. Moreover, based on the present study, ACL-injured patients should undergo reconstruction as early as possible (within one month) to lower the risk of OA.
Background
Soccer is considered the most popular sport in the world concerning both audience and athlete participation, and the incidence of ACL injury in this sport is high. The understanding of injury situations and mechanisms could be useful as substratum for preventive actions. PurposeTo conduct a video analysis evaluating the situations and mechanisms of ACL injury in a homogeneous population of professional male soccer players, through a search entirely performed on the YouTube.com Web site focusing on the most recent years. MethodsA video analysis was conducted obtaining videos of ACL injury in professional male soccer players from the Web site YouTube. Details regarding injured players, events and situations were obtained. The mechanism of injury was defined on the basis of the action, duel type, contact or non-contact injury, and on the hip, knee and foot position. ResultsThirty-four videos were analyzed, mostly from the 2014–2015 season. Injuries occurred mostly in the first 9 min of the match (26%), in the penalty area (32%) or near the side-lines (44%), and in non-rainy conditions (97%). Non-contact injuries occurred in 44% of cases, while indirect injuries occurred in 65%, mostly during pressing, dribbling or tackling. The most recurrent mechanism was with an abducted and flexed hip, with knee at first degrees of flexion and under valgus stress. Conclusions
Through a YouTube-based video analysis, it was possible to delineate recurrent temporal, spatial and mechanical characteristics of ACL injury in male professional soccer players. Level of evidenceLevel IV, case series.
Background:
Reconstruction of anterior cruciate ligament (ACL) tears may potentially prevent the development of secondary meniscal injuries and arthritis.
Purpose/hypothesis:
The purpose of this study was to (1) evaluate the protective benefit of ACL reconstruction (ACLR) in preventing subsequent meniscal tears or arthritis, (2) determine if earlier ACLR (<1 year after injury) offers greater protective benefits than delayed reconstruction (≥1 year after injury), and (3) evaluate factors predictive of long-term sequelae after ACLR. The hypothesis was that the incidence of secondary meniscal tears, arthritis, and total knee arthroplasty (TKA) would be higher in patients treated nonoperatively after ACL tears than patients treated with surgical reconstruction.
Study design:
Cohort study; Level of evidence, 3.
Methods:
This retrospective study included a population-based incidence cohort of 964 patients with new-onset, isolated ACL tears between 1990 and 2000 as well as an age- and sex-matched cohort of 964 patients without ACL tears. A chart review was performed to collect information related to the initial injury, treatment, and outcomes. A total of 509 patients were treated with early ACLR, 91 with delayed ACLR, and 364 nonoperatively. All patients were retrospectively followed (range, 2 months to 25 years) to determine the development of subsequent meniscal tears, arthritis, or TKA.
Results:
At a mean follow-up of 13.7 years, patients treated nonoperatively after ACL tears had a significantly higher likelihood of developing a secondary meniscal tear (hazard ratio [HR], 5.4; 95% CI, 3.8-7.6), being diagnosed with arthritis (HR, 6.0; 95% CI, 4.3-8.4), and undergoing TKA (HR, 16.7; 95% CI, 5.0-55.2) compared with patients treated with ACLR. Similarly, patients treated with delayed ACLR had a higher likelihood of developing a secondary meniscal tear (HR, 3.9; 95% CI, 2.2-6.9) and being diagnosed with arthritis (HR, 6.2; 95% CI, 3.4-11.4) compared with patients treated with early ACLR. Age >21 years at the time of injury, articular cartilage damage, and medial/lateral meniscal tears were predictive of arthritis after ACLR.
Conclusion:
Patients treated with ACLR have a significantly lower risk of secondary meniscal tears, symptomatic arthritis, and TKA when compared with patients treated nonoperatively after ACL tears. Similarly, early ACLR significantly reduces the risk of subsequent meniscal tears and arthritis compared with delayed ACLR.
Theoretical compensation after anterior cruciate ligament (ACL) tear could cause quadriceps weakness and hamstring activation, preventing anterior tibial subluxation and affecting the expected hamstring-to-quadriceps ratio. Although quadriceps weakness often occurs after ACL tears, it remains unclear whether hamstring strength and hamstring-to-quadriceps ratio increase in ACL deficient knees. This meta-analysis compared the isokinetic muscle strength of quadriceps and hamstring muscles, and the hamstring-to-quadriceps ratio, of the injured and injured limbs of patients with ACL tears. This meta-analysis included all studies comparing isokinetic thigh muscle strengths and hamstring-to-quadriceps ratio in the injured and uninjured legs of patients with ACL tear, without or before surgery. Thirteen studies were included in the meta-analysis. Quadriceps and hamstring strengths were 22.3 N∙m (95% CI: 15.2 to 29.3 N∙m; P<0.001) and 7.4 N∙m (95% CI: 4.3 to 10.5 N∙m; P<0.001) lower, respectively, on the injured than on the uninjured side. The mean hamstring-to-quadriceps ratio was 4% greater in ACL deficient than in uninjured limbs (95% CI: 1.7% to 6.3%; P<0.001). Conclusively, Decreases were observed in both the quadriceps and hamstring muscles of patients with ACL tear, with the decrease in quadriceps strength being 3-fold greater. These uneven reductions slightly increase the hamstring-to-quadriceps ratio in ACL deficient knees.
Anterior cruciate ligament (ACL) tears are a common injury, particularly in the athletic and youth populations. The known association between ACL injury and subsequent osteoarthritis (OA) of the knee merits a more in-depth understanding of the relationship between the ACL-injured knee and osteoarthritis. ACL injury, especially with concomitant meniscal or other ligamentous pathology, predisposes the knee to an increased risk of osteoarthritis. ACL insufficiency results in deterioration of the normal physiologic knee bending culminating in increased anterior tibial translation and increased internal tibial rotation. This leads to increased mean contact stresses in the posterior medial and lateral compartments under anterior and rotational loading. However, surgical reconstruction of the ACL has not been shown to reduce the risk of future OA development back to baseline and has variability based on operative factors of graft choice, timing of surgery, presence of meniscal and chondral abnormalities, and surgical technique. Known strategies to prevent OA development are applicable to patients with ACL deficiency or after ACL reconstruction and include weight management, avoidance of excessive musculoskeletal loading, and strength training. Reconstruction of the ACL does not necessarily prevent osteoarthritis in many of these patients and may depend on several external variables.
Aim of this study was to record and compare the functional and activity level as well as the manifestations of osteoarthritis after isolated ACL ruptures between patients with conservative treatment and ACL reconstruction with hamstrings tendon graft.
Thirty-two patients diagnosed with ACL rupture were recorded. Clinical examination included the Tegner and Lysholm activity scale, the International Knee Documentation Committee Subjective Form and KT-1000 arthrometer. Narrowing of the medial and lateral joint spaces was assessed using the IKDC knee examination score.
Median follow-up was 10.3 years (range 10-11). Fifteen patients were conservatively treated (median age 33 years, range 25-39). Seventeen patients were operated (median age 31 years, range 20-36). There was significant difference between the mean values of IKDC scores in favour of the ACL-reconstruction group of patients, 86.8 (SD 6.5) versus 77.5 (SD 13.8), respectively (p = 0.04). The mean value of anteroposterior tibial translation was 1.5 mm (SD 0.2) for ACL-reconstruction group of patients, while the corresponding mean value for ACL-conservative group was 4.5 mm (SD 0.5), p = 0.03. Four patients in ACL-reconstruction group had radiological findings of grade C or D according to IKDC form. In ACL-conservative group, five patients presented similar signs (n.s.).
ACL reconstruction using hamstrings autograft resulted in better functional outcome and laxity measurements than ACL-conservative management. However, the incidence of radiological osteoarthritis was similar between the two groups and independent on the pre-operative grade of laxity and functional status of the patients. Equally, bone bruises were not found as a risk factor for the development of osteoarthritis after ACL rupture.
Prospective randomized study, Level II.
The human body's posture control is a complex system of organs and mechanisms which controls the body's centre of gravity (COG) over its base of support (BOS). Computerised Dynamic Posturography (CDP) allows for the quantitative and objective assessment of the sensory and motor components of the body's posture control system as well as of the integration and adaptation mechanisms in the central nervous system. The aim of this study was to assess the relationships between the body's height and BMI on CDP results in a group of young healthy women without any clinical symptoms of balance disorders. It was found that the MS depended significantly on the height and BMI of the subjects as well as on the SOT conditions. As the height and BMI increased the MS value decreased. The postural response latency (LC) in the MCT statistically significantly depended only on height and showed a positive correlation. The postural response latency increased with height. The postural response amplitude for both right and left lower limbs significantly depended on height and BMI, but only for the backward movement of the platform. The response amplitude for all platform translations under all MCT conditions increased with height and BMI. The body's resultant imbalance caused by the platform perturbations in the ADT was greater in shorter people and those with a lower BMI.
Objetivo
Investigar, por meio do teste de reprodução da força, a existência de déficits proprioceptivos entre o membro lesionado e o não lesionado (i.e., contralateral normal) em indivíduos que tenham sofrido ruptura total de LCA.
Métodos
Participaram do estudo 16 pacientes com ruptura total do LCA. Foi feito o teste de força voluntária máxima isométrica (FVIM) e reprodução da força muscular no membro com ruptura total do LCA e contralateral saudável, com joelho a 60° de flexão. Foi usada a intensidade-meta para o procedimento de 20% da FVMI. O desempenho proprioceptivo foi determinado por meio dos valores de erro absoluto (EA), erro variável (EV) e erro constante (EC).
Resultados
Diferenças significativas foram encontradas entre os grupos controle e LCA para as variáveis erro absoluto (p = 0,05) e erro constante (p = 0,01). Não foi encontrada diferença para o erro variável (p = 0,83).
Conclusão
Nossos dados corroboram a hipótese de existência de déficit proprioceptivo em sujeitos com ruptura total de LCA em um membro lesionado quando comparado com o não lesionado durante a avaliação do senso da força. Esse déficit pode ser explicado por uma perda total ou parcial dos mecanorreceptores do LCA.
Meniscal injuries are recognized as a cause of significant musculoskeletal morbidity. The menisci are vital for the normal function and long-term health of the knee joint. The purpose of this review is to provide current knowledge regarding the anatomy and biomechanical functions of the menisci, incidence, injury patterns and the advancements in treatment options of meniscal injury. A literature search was performed by a review of PubMed, Google Scholar, MEDLINE, and OVID for all relevant articles published between 1897 and 2014. This study highlights the anatomical and biomechanical characteristics of the menisci, which may be relevant to injury patterns and treatment options. An understanding of the normal anatomy and biomechanical functions of the knee menisci is a necessary prerequisite to understanding pathologies associated with the knee. Clin. Anat., 2014. © 2014 Wiley Periodicals, Inc.
Despite the frequent assertion that the weather conditions change the intensity of pain in osteoarthritis (OA), this influence is controversial and difficult to measure. This analysis aims to review articles related to the influence of meteorological elements in the OA pain. The literature review was performed with the bibliographical survey databases of the Medical Literature Analysis and Retrieval System Online (MEDLINE) and the Latin American and Caribbean Health Sciences (LILACS), and active search in the list of references of the articles and reviews retrieved. The inclusion criteria for this analysis were prospective studies that evaluated the presence of pain related to some variable of weather in OA patients. The articles were published in Portuguese, English, and Spanish. Of the 247 abstracts analyzed, eight (3.2%) included articles from the electronic database consulted (n = 7), and active case finding (n = 1). Atmospheric pressure was the most frequently variable with some influence on OA pain in five of the included studies, while precipitation was less related to the symptoms of OA; wind was not analyzed. Despite the methodological diversity and biases of the analyzed studies, there is a trend to confirm the influence of weather in OA pain intensity, mainly in more recent publications. Besides checking the effect of meteorological elements in the OA pain, it is necessary to evaluate the interference in daily activities and impairing of the quality of life.
To examine all cause and disease specific mortality in patients with osteoarthritis of the knee or hip.
Population based cohort study.
General practices in the southwest of England.
1163 patients aged 35 years or over with symptoms and radiological confirmation of osteoarthritis of the knee or hip.
Age and sex standardised mortality ratios and multivariable hazard ratios of death after a median of 14 years' follow-up.
Patients with osteoarthritis had excess all cause mortality compared with the general population (standardised mortality ratio 1.55, 95% confidence interval 1.41 to 1.70). Excess mortality was observed for all disease specific causes of death but was particularly pronounced for cardiovascular (standardised mortality ratio 1.71, 1.49 to 1.98) and dementia associated mortality (1.99, 1.22 to 3.25). Mortality increased with increasing age (P for trend <0.001), male sex (adjusted hazard ratio 1.59, 1.30 to 1.96), self reported history of diabetes (1.95, 1.31 to 2.90), cancer (2.28, 1.50 to 3.47), cardiovascular disease (1.38, 1.12 to 1.71), and walking disability (1.48, 1.17 to 1.86). However, little evidence existed for increased mortality associated with previous joint replacement, obesity, depression, chronic inflammatory disease, eye disease, or presence of pain at baseline. The more severe the walking disability, the higher was the risk of death (P for trend <0.001).
Patients with osteoarthritis are at higher risk of death compared with the general population. History of diabetes, cancer, or cardiovascular disease and the presence of walking disability are major risk factors. Management of patients with osteoarthritis and walking disability should focus on effective treatment of cardiovascular risk factors and comorbidities, as well as on increasing physical activity.
Few prospective long-term studies of more than 10 years have reported changes in knee function and radiologic outcomes after anterior cruciate ligament (ACL) reconstruction.
To examine changes in knee function from 6 months to 10 to 15 years after ACL reconstruction and to compare knee function outcomes over time for subjects with isolated ACL injury with those with combined ACL and meniscal injury and/or chondral lesion. Furthermore, the aim was to compare the prevalence of radiographic and symptomatic radiographic knee osteoarthritis between subjects with isolated ACL injuries and those with combined ACL and meniscal and/or chondral lesions 10 to 15 years after ACL reconstruction.
Cohort study; Level of evidence, 2.
Follow-up evaluations were performed on 221 subjects at 6 months, 1 year, 2 years, and 10 to 15 years after ACL reconstruction with bone-patellar tendon-bone autograft. Outcome measurements were KT-1000 arthrometer, Lachman and pivot shift tests, Cincinnati knee score, isokinetic muscle strength tests, hop tests, visual analog scale for pain, Tegner activity scale, and the Kellgren and Lawrence classification.
One hundred eighty-one subjects (82%) were evaluated at the 10- to 15-year follow-up. A significant improvement over time was revealed for all prospective outcomes of knee function. No significant differences in knee function over time were detected between the isolated and combined injury groups. Subjects with combined injury had significantly higher prevalence of radiographic knee osteoarthritis compared with those with isolated injury (80% and 62%, P = .008), but no significant group differences were shown for symptomatic radiographic knee osteoarthritis (46% and 32%, P = .053).
An overall improvement in knee function outcomes was detected from 6 months to 10 to 15 years after ACL reconstruction for both those with isolated and combined ACL injury, but significantly higher prevalence of radiographic knee osteoarthritis was found for those with combined injuries.
The incidence of osteoarthritis after anterior cruciate ligament reconstruction is disturbingly high, with reports of nearly 50% of patients developing mild to moderate osteoarthritis 6 years after surgery. Few studies have assessed the factors involved in the development of osteoarthritis.
The following 10 factors will be found to be predictive of osteoarthritis: meniscectomy, chondral damage, patellar tendon grafting, age at surgery, time delay between injury and surgery, type and intensity of postsurgery sport, quadriceps strength, hamstring strength, quadriceps-to-hamstring strength ratio, and residual joint laxity.
Cohort study (prognosis); Level of evidence, 1.
Fifty-six subjects with anterior cruciate ligament reconstruction were followed for 6 years after surgery. Assessment included KT-1000 arthrometer testing, isokinetic strength testing, a return-to-sport questionnaire, and a radiograph assessment. A discriminant analysis was performed to assess which of the 10 factors could discriminate between those patients who developed tibiofemoral and patellofemoral osteoarthritis and those who did not.
Five factors were found to be predictive of tibiofemoral osteoarthritis. Meniscectomy (r = .72) and chondral damage (r = .41) were the strongest discriminators, followed by patellar tendon grafting (r = .37) (chi(2) [7, n = 56] = 25.48; P = .001). Weak quadriceps (r = .39) and low quadriceps-to-hamstring strength ratios (r = .6) were very close discriminators (chi(2) [8, n = 42] = 15.02; P = .059). For patellofemoral osteoarthritis, meniscectomy (r = .45), chondral damage (r = .75), and age at surgery (r = .65) were predictors or close predictors (chi(2) [7, n = 54] = 13.30; P = .065).
As not all 10 factors studied were predictive of osteoarthritis, the hypothesis was only partially proven. Preventing further meniscal and chondral damage in patients with anterior cruciate ligament deficiency is critical. Grafting using the hamstring tendons and restoration of quadriceps-to-hamstring strength balance are associated with less osteoarthritis.
In a one month prospective study of 62 rheumatic patients--16 with rheumatoid arthritis (RA), 24 with osteoarthritis (OA), 11 with inflammatory arthritis, 11 with fibromyalgia joint pain--swelling and everyday activity was compared with changes in daily weather conditions. In most patients weather changes increased arthritic symptoms. Women were more sensitive to weather than men (62% v 37%). Pain was affected positively by barometric pressure and temperature in RA, by temperature, rain, and barometric pressure in OA, and by barometric pressure in fibromyalgia. These results support the belief of most rheumatic patients that weather conditions significantly influence their day to day symptoms.
We studied the extent to which automatic postural actions in standing human subjects are organized by a limited repertoire of central motor programs. Subjects stood on support surfaces of various lengths, which forced them to adopt different postural movement strategies to compensate for the same external perturbations. We assessed whether a continuum or a limited set of muscle activation patterns was used to produce different movement patterns and the extent to which movement patterns were influenced by prior experience. Exposing subjects standing on a normal support surface to brief forward and backward horizontal surface perturbations elicited relatively stereotyped patterns of leg and trunk muscle activation with 73- to 110-ms latencies. Activity began in the ankle joint muscles and then radiated in sequence to thigh and then trunk muscles on the same dorsal or ventral aspect of the body. This activation pattern exerted compensatory torques about the ankle joints, which restored equilibrium by moving the body center of mass forward or backward. This pattern has been termed the ankle strategy because it restores equilibrium by moving the body primarily around the ankle joints. To successfully maintain balance while standing on a support surface short in relation to foot length, subjects activated leg and trunk muscles at similar latencies but organized the activity differently. The trunk and thigh muscles antagonistic to those used in the ankle strategy were activated in the opposite proximal-to-distal sequence, whereas the ankle muscles were generally unresponsive. This activation pattern produced a compensatory horizontal shear force against the support surface but little, if any, ankle torque. This pattern has been termed the hip strategy, because the resulting motion is focused primarily about the hip joints. Exposing subjects to horizontal surface perturbations while standing on support surfaces intermediate in length between the shortest and longest elicited more complex postural movements and associated muscle activation patterns that resembled ankle and hip strategies combined in different temporal relations. These complex postural movements were executed with combinations of torque and horizontal shear forces and motions of ankle and hip joints. During the first 5-20 practice trials immediately following changes from one support surface length to another, response latencies were unchanged. The activation patterns, however, were complex and resembled the patterns observed during well-practiced stance on surfaces of intermediate lengths.(ABSTRACT TRUNCATED AT 400 WORDS)
We examined whether somatosensory evoked potentials (SEPs) were detectable after direct electrical stimulation of injured, reconstructed and normal anterior cruciate ligaments (ACL) during arthroscopy under general anaesthesia. We investigated the position sense of the knee before and after reconstruction and the correlation between the SEP and instability.
We found detectable SEPs in all ligaments which had been reconstructed with autogenous semitendinosus and gracilis tendons over the past 18 months as well as in all cases of the normal group. The SEP was detectable in only 15 out of 32 cases in the injured group, although the voltages in the injured group were significantly lower than those of the controls. This was not the case in the reconstructed group. The postoperative position sense in 17 knees improved significantly, but there was no correlation between it and the voltage. The voltage of stable knees was significantly higher than that of the unstable joints. Our findings showed that sensory reinnervation occurred in the reconstructed human ACL and was closely related to the function of the knee.
Even though specific adjustments of the multi-joint control of posture have been observed when posture is challenged, multi-joint coordination on a seesaw device has never been accurately assessed. The current study was conducted in order to investigate the multi-joint coordination when subjects were standing on either a seesaw device or on a stable surface, with the eyes open or closed. Eighteen healthy active subjects were recruited. A principal component analysis and a Self-Organizing Maps analysis were performed on the joint angles in order to detect and characterize dominant coordination patterns. Intermuscular EMG coherence was analysed in order to assess the neurophysiological mechanisms associated with these coordination patterns. The results illustrated a multi-joint organization of posture on both stable ground and on the seesaw, with a higher variability among the individual postural responses observed when standing on the seesaw. These findings challenge the classical assumption of ankle mechanisms as dominating control on seesaw devices and confirm that inter-joint coordination in postural control is strongly modulated by stance conditions. When standing on the seesaw without vision, a decrease in intermuscular coherence was observed without any impact on the joint coordination patterns, likely due to an increase dependence on proprioceptive information.
Background:
Because of a reduction in the number of mechanoreceptors or alterations of their characteristics, anterior cruciate ligament (ACL) tears lead not only to mechanical instability but also to impaired proprioception. Purpose/Hypothesis: This study analyzed whether ACL tears cause a greater decrease in proprioception in injured than in uninjured knees. The hypothesis was that knee proprioception after ACL tears would decrease more in injured than in contralateral uninjured knees, regardless of the method used to measure knee proprioception.
Study design:
Meta-analysis.
Methods:
We identified studies comparing proprioception in ACL-injured and contralateral intact knees using threshold for detection of passive motion (TTDPM) or joint position sense (JPS) tests. JPS was assessed by measuring the reproduction of passive positioning (RPP) or active repositioning (RAP) of the knee.
Results:
Sixteen studies were included in this meta-analysis. The pooled results of subgroup analyses of TTDPM for both 20° and 40° of knee flexion showed that mean angle of error was 0.23° (95% CI, 0.08°-0.37°) greater in ACL-injured than in contralateral intact knees ( P = .002). Pooled data RAP and RPP subgroup analyses also showed that the mean angle of error was 0.94° higher in ACL-injured than in contralateral intact knees. The mean difference in angle of error between ACL-injured and contralateral intact knees was 0.71° greater (95% CI, 0.68°-0.74°; P < .001) by JPS than by TTDPM.
Conclusion:
Proprioception of ACL-injured knees was decreased compared with contralateral intact knees, as determined by both joint movement (kinesthesia) and joint position. The magnitude of loss of proprioception was greater in joint position than in joint movement.
Introduction
L’instabilité du genou, liée à une lésion du ligament croisé antérieur, est traitée par reconstruction chirurgicale. Pendant la période de transformation histologique du transplant devenant néo-ligament, la privation d’informations proprioceptives musculo-tendino-articulaires est importante. Cette étude en cours vise à comparer les bénéfices d’un protocole de rééducation innovant (prise en charge [PEC] à sec, PEC en milieu aquatique) à ceux d’un protocole de rééducation conventionnelle (recommandations Haute autorité de Santé 2008) en termes de cinétique de récupération et de développement des compétences proprioceptives des sportifs opérés d’une ligamentoplastie du genou.
Matériel et méthodes
À ce jour, 76 patients ont été répartis en deux groupes de rééducation (randomisation) ; ainsi, 40 patients ont suivi un protocole de rééducation conventionnelle (Gr 1) et 36 un protocole associant une rééducation conventionnelle à durée réduite avec une rééducation en milieu aquatique (Gr 2). La durée totale de PEC était identique dans les deux groupes. Un bilan posturographique a permis d’évaluer la qualité du contrôle postural avant intervention chirurgicale (E1), puis 15 jours (E2, début de la rééducation propre au protocole de recherche), 1 mois (E3, fin de la rééducation propre au protocole de recherche), 2 mois (E4) et 6 mois (E5) après intervention chirurgicale. L’intensité de la douleur a également été évaluée (échelle EVA).
Résultats
Une amélioration du contrôle postural est observée entre E2 et E3 dans les deux groupes (p < 0,05). Une diminution de la douleur dans les deux groupes entre E2 et E3 (p < 0,05) et dans le Gr2 entre E4 et E5 (p < 0,05) est observée.
Discussion–conclusion
Concernant l’analyse transversale pour la comparaison entre les deux groupes, il est nécessaire d’inclure l’effectif initialement déterminé sur le plan statistique, c’est-à-dire 128 patients afin d’évaluer l’efficacité d’un programme de rééducation innovant sur un retour aux activités sociales, sportives et professionnelles plus précoce.
Objective:
To quantify the risk of knee pain exacerbation associated with temperature, relative humidity, air pressure and precipitation in persons with knee osteoarthritis.
Method:
a web-based case-crossover study was conducted. Participants with a diagnosis of symptomatic, radiographic knee osteoarthritis were measured at baseline and followed for 3 months. Participants were instructed to log on to the study website if they perceived experiencing knee pain exacerbation (hazard period). Pain exacerbation was defined as an increase of ≥ 2 on a 0-10 numeric rating scale from the participant's mildest pain reported at baseline. A time-stratified case-crossover study was conducted to anchor the corresponding hazard date to 4 control periods within a particular 35-day interval. Data on maximum and minimum temperature ((o)C), relative humidity (%), barometric pressure (hPa) and precipitation (mm) were obtained for the hazard and control periods from the publicly available meteorological database of the Australian Bureau of Meteorology. The associations were assessed using conditional logistic regression.
Results:
Of the 345 participants recruited, 171 participants (women: 64%, mean age: 62 years, mean BMI: 30.2 kg/m2) experienced at least one episode of pain exacerbation, yielding 1,425 observations included in the analyses. There was no apparent association between temperature, relative humidity, air pressure or precipitation and risk of knee pain exacerbation.
Conclusion:
Despite anecdotal reports from patients, change in weather factors does not appear to influence the risk of pain exacerbation in persons with knee osteoarthritis. Additional studies should quantify the association of weather and risk of pain exacerbation in regions with more extreme weather conditions.
Background Knee reinjury after ACL reconstruction is common and increases the risk of osteoarthritis. There is sparse evidence to guide return to sport (RTS) decisions in this population.
Objectives To assess the relationship between knee reinjury after ACL reconstruction and (1) return to level I sports, (2) timing of RTS and (3) knee function prior to return.
Methods 106 patients who participated in pivoting sports participated in this prospective 2-year cohort study. Sports participation and knee reinjury were recorded monthly. Knee function was assessed with the Knee Outcome Survey—Activities of Daily Living Scale, global rating scale of function, and quadriceps strength and hop test symmetry. Pass RTS criteria were defined as scores >90 on all tests, failure as failing any.
Results Patients who returned to level I sports had a 4.32 (p=0.048) times higher reinjury rate than those who did not. The reinjury rate was significantly reduced by 51% for each month RTS was delayed until 9 months after surgery, after which no further risk reduction was observed. 38.2% of those who failed RTS criteria suffered reinjuries versus 5.6% of those who passed (HR 0.16, p=0.075). More symmetrical quadriceps strength prior to return significantly reduced the knee reinjury rate.
Conclusions Returning to level I sports after ACL reconstruction leads to a more than 4-fold increase in reinjury rates over 2 years. RTS 9 months or later after surgery and more symmetrical quadriceps strength prior to return substantially reduce the reinjury rate.
To overcome many of the complications after ACL reconstruction (prolonged knee stiffness, limitation of complete extension, delay in strength recovery, anterior knee pain), yet still maintain knee stability, we developed a rehabilitation protocol that emphasizes full knee extension on the first postoperative day and immediate weightbearing according to the patient's tolerance. Of 800 patients who underwent intraarticular ACL patellar tendon-bone graft reconstruction, performed by the same surgeon, the last 450 patients have followed the accelerated rehabilitation schedule as outlined in the protocol. A longer than 2 year followup is recorded for 73 of the patients in the accelerated rehabilitation group. On the 1st postoperative day, we encouraged these patients to walk with full weightbearing and full knee extension. By the 2nd postoperative week, the patients with a 100 degree range of motion participated in a guided exercise and strengthening program. By the 4th week, patients were permitted unlimited activities of daily living and were allowed to return to light sports activities as early as the 8th week if the Cybex strength scores of the involved extremity exceeded 70% of the scores of the noninvolved extremity and the patient had completed a sport-specific functional/agility program. The patient database was compiled from frequent clinical examinations, periodic knee questionnaires, and objective information, such as range of motion measurements, KT-1000 values, and Cybex strength scores. A series of graft biopsies obtained at various times have revealed no adverse histologic reaction.(ABSTRACT TRUNCATED AT 250 WORDS)
The paper describes the concepts of primary and secondary restraints to knee joint stability and explains systematically how the tibia is stabilised against translational forces and rotational torques in different directions and axes, and how those vary across the arc of flexion-extension. It also shows how the menisci act to stabilise the knee, in addition to load carrying across the joint. It compares the properties of the natural stabilising structures with the strength and stiffness of autogenous tissue grafts and relates those strengths to the strength of graft fixation devices. A good understanding of the biomechanical behaviour of these various structures in the knee will help the surgeon in the assessment and treatment of single and multi-ligament injuries.
The assessment of joint amplitude is a qualitative and quantitative investigation technique that allows not only to quantify joint deflection and orthopaedic deformation, but also to analyse pain and sensations of end of running. In association with other investigation techniques, it helps establishing both diagnosis and adequate therapy, and to evaluate subsequent improvement. Compensating insufficiently reliable subjective joint evaluation by objective and quantified amplitude assessments is mandatory. Numerous techniques exist and each therapist has to select the most adequate method, depending on both the pathological problem and the available means. Joint amplitude assessment may be expressed by goniometry-based angle values, centimetre values, or using numerical testing.
A scheme for understanding the organization of human postural movements is developed in the format of a position paper. The structural characteristics of the body and the geometry of muscular actions are incorporated into a three-dimensional graphical representation of human movement mechanics in the sagittal plane. A series of neural organizational hypotheses limit a theoretically infinite number of combinations of muscle contractions and associated movement trajectories for performing postural corrections: (1) Controls are organized to use the minimum number of muscles; (2) frequently performed movements are organized to require a minimum of neural decision-making.
These hypotheses lead to the prediction that postural movements are composed of muscle contractile strategies derived from a limited set of distinct contractile patterns. The imposition of two mechanical constraints related to the configuration of support and to requirements for body stability with respect to gravity predict the conditions under which individual movement strategies will be deployed.
A complementary organizational scheme for the senses is developed. We show that organization of postural movements into combinations of distinct strategies simplifies the interpretation of sensory inputs. The fine-tuning of movement strategies can be accomplished by breaking down the complex array of feedback information into a series of scalar quantities related to the parameters of the movement strategies. For example, the magnitude, aim, and curvature of the movement trajectory generated by an individual strategy can be adjusted independently.
The second half of the report compares theoretical predictions with a series of actual experimental observations on normal subjects and patients with known sensory and motor disorders. Actual postural movements conform to theoretical predictions about the composition of individual movement strategies and the conditions under which each strategy is used. Observations on patients suggest how breakdowns in individual steps within the logical process of organization can lead to specific movement abnormalities.
Discussion focuses on the areas needing further experimentation and on the implications of the proposed organizational scheme. We conclude that although our organizational scheme is not new in demonstrating the need for simplifying the neural control of movement, it is perhaps original in imposing discrete logical control upon a continuous mechanical system. The attraction of the scheme is that it provides a framework compatible with both mechanical and physiological information and amenable to experimental testing.
ABSTRACT Postural control impairments and dizziness, which are major health problems with high secondary morbidity and mortality, increase with aging. Elevated homocysteine (Hcy) level is an age-related metabolic disorder, known to be involved in cardiovascular, neurological, and multisensory dysfunctions. Elevated Hcy level might be involved in sensory balance control systems impairment and dizziness occurrence. Dizziness, fitness Instrumental Activity of Daily Living scale (fitness IADL), systolic arterial pressure with ankle-brachial blood pressure index and homocysteinemia were studied in 61 noninstitutionized elderly women. Clinical balance tests (timed "Up and Go", 10-m walking and one-leg balance) and posturography (including sensory conflicting situations [SCS] and cognitive conflicting situations [CCS]) were performed. Clinical balance control was lower in dizzy women who presented particularly poor stability in SCS. Dizziness was related to low fitness IADL scores (odds ratio [OR] 0.452, 95% CI 0.216-0.946) and to elevated Hcy (OR 8.084, 95% CI 1.992-32.810). Elevated Hcy was correlated with balance disorders both in SCS and CCS. Dizziness is associated with a reduced ability in balance control management. Hcy is related both to dizziness and low postural performance. This relation between elevated Hcy levels and balance impairments, resulting in dizziness, may be explained by its angiotoxicity and neurotoxicity.
Objective: Many rheumatology patients report exacerbation of joint symptoms with weather changes. We report the first of a two-part study on the influence of weather on rheumatological conditions. This survey aims to describe perceived weather sensitivity in our patient population.
Methods: Two hundred rheumatology patients seen consecutively in a tertiary hospital were given a 10-item questionnaire (Jamieson). This questionnaire has been well validated with good test-retest reliability (r = 0.91) and ability to distinguish patients with weather sensitivity. New patients and soft tissue clinic patients were not included.
Results: Seventy-four percent of patients reported weather sensitivity, with humidity and low temperature reported most frequently as being associated with worsening of symptoms (66% and 72%, respectively). Seventy percent of weather sensitive subjects described pain exacerbation prior and/or during weather changes. Various rheumatological conditions had similar rates of weather sensitivity, except fibromyalgia which reported 100% weather sensitivity.
Conclusion: A significant proportion of rheumatology patients report weather sensitivities. Further studies would be useful to further explore actual versus perceived effects of weather as this may have behavioural, housing and medical implications. Our discussion includes a brief summary of current literature and various postulates why patients may have increased weather sensitivity.
This study examines the structure of sensory nerve endings in the sheep anterior cruciate ligament (ACL). Three types of nerve endings are found: free nerve endings (FNE), Ruffini corpuscles, and lamellated corpuscles.The FNE (more than 100) are found subsynovially. The afferent nerve fibres are either thin myelinated axons (Aδ) or C fibres with diameters of 1–2 μm. FNE have been reported to function as thermoreceptors and polymodal nociceptors. In addition, FNE are also seen between fascicles of collagen fibres, often close to blood vessels. Part of this group may be efferent autonomic fibres controlling local blood flow.The corpuscles are seen subsynovially and between fascicles of connective tissue close to the attachment points of the ACL. A ligament contains about 20 Ruffini corpuscles, which are mainly located in the subsynovial connective tissue. They consist of cylinders formed from perineural cells surrounding the afferent myelinated axons (diameters 4–5 μm) with enlarged nerve terminals anchored between collagen fibres. These enter in bundles from the surrounding connective tissue at one open pole, pass through the length of the cylinder, and leave at the other pole. Functionally, Ruffini corpuscles have been described as slowly adapting stretch receptors.Lamellated corpuscles (usually between 5 and 15) are found in the subsynovial connective tissue. The afferent myelinated axon has a diameter of 4–6 μm, and the nerve terminal is located in the centre of numerous layers formed by lamellated terminal glial cells and by a perineural capsule. They are known to function as rapidly adapting pressure receptors.The most important function of the ACL is its mechanical function, but additional sensory functions must be considered triggering reflex mechanisms in case of extreme positioning or overload. Anat Rec 254:13–21, 1999. © 1999 Wiley-Liss, Inc.
The anatomic forms of diarthrodial joints are important structural features which provide and limit the motions required for the joint. Typically, the length scale of topographic variation of anatomic forms ranges from 0.5 to 15 cm. Articular cartilage is the thin layer of hydrated soft tissue (0.5–5.0 mm thick) covering the articulating bony ends in diarthrodial joints. This tissue has a set of unique mechanical and physicochemical properties which are responsible for its load-carrying capabilities and near-frictionless qualities. The mechanical properties of articular cartilage are determined at the tissue-scale level and these properties depend on the composition of the tissue, mainly collagen and proteoglycan, and their molecular and ultrastructural organization (ultra-scale: 10−8–10−6m). Because proteoglycans possess a high density of fixed negative charges, articular cartilage exhibits a significant Donnan osmotic pressure effect. This physicochemically derived osmotic pressure is an important component of the total swelling pressure; the other component of the total swelling pressure stems from the charge-to-charge repulsive force exerted by the closely spaced (1–1.5 nm) negative charge groups along the proteoglycan molecules. Thus these interactions take place at a nano-scale level: 10−10–10−9 m. Finally, cartilage biochemistry and organization are maintained by the chondrocytes which exist at a micro-scale level (10−7–10−6 m). Significant mechanoelectro-chemical transduction occurs within the extracellular matrix at the micro-scale level which affects and modulates cellular anabolic and catabolic activities. At present, the exact details of these transduction mechanisms are unknown. In this review, we present a summary of the hierarchical features for articular cartilage and diarthrodial joints and tables of known material properties for cartilage. Also we summarize how the multi-scale interactions in articular cartilage provide for its unique material properties and tribological characteristics.
Evidence suggests that single-bundle anterior cruciate ligament (ACL) reconstruction does not reliably prevent the development of knee osteoarthritis (OA).
This study was conducted to determine the overall prevalence of and risk factors for the development of radiographic knee OA after single-bundle ACL reconstruction.
Case control study; Level of evidence, 3.
There were 249 individuals who had undergone primary single-bundle ACL reconstruction included in this retrospective cohort study. Follow-up radiographs were scored by a single orthopaedic surgery sports medicine fellow using the Kellgren-Lawrence (KL) scale to determine the degree of OA in the medial, lateral, and patellofemoral compartments. Radiographic OA of the involved knee was considered to be present if, compared with the noninvolved knee, there was at least a 2-grade difference in the KL score in at least 1 compartment or a 1-grade difference in at least 2 compartments. Predictors of OA that were explored included patient age, sex, body mass index (BMI), smoking status activity level, meniscectomy before or concurrent with ACL reconstruction, chondral injury present at the time of ACL reconstruction, graft type and source, tibial and femoral tunnel positions, need for revision, and length of follow-up. Univariable and stepwise multivariable logistic regressions were used to identify factors that were associated with radiographic knee OA.
Thirty-nine percent of the patients had radiographic OA an average of 7.8 years after surgery. Female sex, BMI, time from injury to surgery, medial and patellofemoral compartment chondrosis, prior medial or lateral meniscectomy, concurrent medial meniscectomy, and length of follow-up were associated with radiographic knee OA after ACL surgery. Stepwise multivariable logistic regression indicated that prior medial meniscectomy (95% confidence interval [CI], 1.39-6.85), grade 2 or greater medial chondrosis (95% CI, 1.27-6.73), length of follow-up (95% CI, 1.07-1.24), and BMI (overweight 95% CI, 1.08-3.84; obese 95% CI, 1.34-7.80) were the best set of predictors of knee OA.
Despite reduced laxity and instability and improved activity and participation, individuals who have undergone ACL reconstruction are still at high risk for developing knee OA compared with the general population. The strongest predictors of knee OA after ACL reconstruction were obesity and grade 2 or greater chondrosis in the medial compartment. These results may aid in identifying patients at risk for OA after ACL reconstruction.
Mortality has not been a major area of investigation in osteoarthritis. The author conducted a systematic review and identified seven studies that provided data on either mortality or survival in persons with osteoarthritis; an additional two articles with relevant data were identified through review of reference lists. Studies included persons with radiographic evidence of osteoarthritis as well as clinical samples of patients with osteoarthritis. Results were pooled using the method of best evidence synthesis. Overall, there was moderate evidence of increased mortality among persons with osteoarthritis compared with the general population. Increased cause-specific mortality was observed in some studies from cardiovascular and gastrointestinal disorders. Risk factors for mortality in persons with osteoarthritis included an increased burden of osteoarthritis, advanced age, and presence of comorbid conditions. Possible explanations for the excess mortality include reduced levels of physical activity among persons with osteoarthritis due to involvement of lower limb joints and presence of comorbid conditions, as well as adverse effects of medications used to treat symptomatic osteoarthritis, particularly non-steroidal anti-inflammatory drugs.
Bathing in water (balneotherapy or spa therapy) has been frequently and widely used in classical medicine as a cure for diseases. This paper reviews the present literature on the use of balneotherapy in dermatologic, chronic musculoskeletal (inflammatory and non-inflammatory), metabolic and psychological conditions.
We performed a systematic review on related papers appearing in the Medline and Cochrane Library database from 1966 to 2003 that included randomized controlled and non-randomized clinical trials using balneotherapy. We also determined to reflect where possible the chemical compositions of spas.
The major dermatologic and musculoskeletal diseases that are frequently treated by balneotherapy with a remarkable rate of success are atopic dermatitis, psoriasis, rheumatoid arthritis (RA), ankylosing spondylitis, osteoarthritis and low back pain. Moreover, the effects of spa therapy on several metabolic conditions are discussed. The mechanisms by which broad spectrums of diseases respond to spa therapy probably incorporate chemical, thermal and mechanical effects.
The importance of balneotherapy either alone or as complement to other therapies should be considered after, or accompanying, orthodox medical treatments.
This study aimed to evaluate the role of the knee joint in the neurosensory organization of balance control and the generation of postural sensorimotor strategies. Ten patients, aged over 60 years and having undergone unilateral total knee replacement (TKR) for osteoarthritis, and 20 controls were submitted to static and dynamic posturographic tests and to a sensory organization test (SOT) aiming at evaluating postural control in quiet stance and during movement. The patients were submitted to these evaluations after the disappearance of pain (TKR(1)) and at the end of a 6-week rehabilitation program (TKR(2)). Balance control being greatly improved at TKR2 compared to TKR1, the patients attain a quality of postural regulation similar to that of the controls; some postural abnormalities did however persist for the static test. Moreover, SOT values at TKR(2) close to those of the controls highlighted an improvement in motor response, better management in altered proprioceptive information situations, and greater use of the ankle to control balance. This model of intervention on the knee joint, namely knee replacement due to osteoarthritis, has shown that gradual functional sensorimotor restoration after TKR, due to intrasensory proprioceptive compensation either at knee, or at other joint levels (hip/ankle), improves dynamic balance control. This reacquisition allows the knee joint to recover its corrective compensatory role in postural regulation allowing, through neuroplasticity, the modification of muscular activation sequences and, thus, the implementation of anticipatory sensorimotor strategies.
Hubbard TJ, Hicks-Little C, Cordova M. Changes in ankle mechanical stability in those with knee osteoarthritis.
To examine ankle joint mechanical stability in patients who had mild to moderate knee osteoarthritis (OA).
Case control study.
Biodynamics research laboratory.
Subjects with knee OA (n=15; 5 men and 10 women; mean age +/- SD, 60.3+/-10.2y; mean mass +/- SD, 93.9+/-18.3kg; mean height +/- SD, 167.23+/-9.5cm) were matched to healthy controls (n=15; 5 men and 10 women; mean age +/- SD, 59.6+/-12.6y; mean mass +/- SD, 83.5+/-19.2kg; mean height +/- SD, 169.7+/-12.6cm).
Not applicable.
Mechanical ankle-subtalar joint stability was assessed with an instrumented arthrometer where ankle-subtalar joint motion for anterior/posterior displacement and inversion/eversion rotation was measured. Separate 2 x 2 mixed model analyses of variance were performed.
Significant group x side interactions were observed for anterior and posterior displacement (P<.05) where patients with knee OA had significantly less anterior and posterior ankle displacement compared with the control group, as well as compared with their unaffected extremity. Additionally, patients with knee OA had significantly (P<.05) less inversion/eversion rotation than their respective controls.
These data suggest that altered ankle joint mechanics may be the result of deviations in ankle joint alignment secondary to the structural changes at the knee. Compensatory changes in ankle joint mechanics must also be considered when addressing lower extremity functional deficits in patients with knee OA.
High-level occupational exposure to volatile organic solvents may elicit neurotoxic effects, especially on central and peripheral structures involved in balance ability. Studies on balance control in relation with exposure levels close to the threshold limit values are scarce. This study aimed to assess the neurotoxic effects of chronic and subchronic exposure to organic solvents among workers in plant manufacturing adhesive materials. Balance control was evaluated in 18 subjects, mainly exposed to n-hexane and toluene, with current median exposure levels of 222 and 102 mg/m(3), respectively, and a median exposure duration of 21 years, and in 32 nonexposed controls, using posturography tests with and without sensory conflicting situations. Tests were undergone at the beginning of the work shift (chronic exposure) following a week end, and after 72 h (subchronic exposure). Balance control performance was lower in chronically exposed workers compared to controls, and got worse after subchronic exposure, particularly during situations, where vestibular information was important. Our study suggests that a low-level and prolonged exposure to volatile organic solvents, mainly n-hexane and toluene, in the workplace is associated with deleterious central effects involved in postural regulation. This neurotoxicity is characterized by difficulties to use the most relevant information to control balance, leading to altered management of sensory conflicting situations.
Proprioception and muscle strength are both reported to influence single-limb stance balance in patients with chronic anterior cruciate ligament (ACL) injuries. However, the effects of these parameters on dynamic stance balance in such patients are currently unknown. This study was undertaken to ascertain whether proprioception, muscle strength, and knee laxity are correlated with dynamic standing balance in patients with ACL deficiency. Ten young men with unilateral ACL deficiency participated in this study. The mean time interval from the injury to the study was 12.8 months. Knee laxity measurements, passive re-positioning (PRP) and threshold for detection of passive motion (TTDPM) proprioception tests, quadriceps and hamstring muscle strength tests, and dynamic single-limb balance tests were performed for both injured and uninjured limbs. Significant differences between the injured and uninjured sides were observed for all test parameters. As independent variables, knee laxity, PRP proprioception, and muscle strength did not correlate with dynamic standing balance for the injured limb. However, a significant positive correlation (P<0.05) between TTDPM proprioception and dynamic single-limb stance balance was observed for the injured limb. To improve dynamic single-limb stance balance in patients with ACL injuries, training in TTDPM proprioceptive ability is recommended as the most important initial approach for such patients.
Posture and balance may be affected in many spine or lower-limb disorders. An extensive evaluation including clinical tests and movement analysis techniques may be necessary to characterize how rheumatologic or orthopedic diseases are related to static or dynamic changes in postural control. In lower limbs, unbalance may be related to a decreased stability following arthrosis or ligament injuries at knee or ankle levels, while hip lesions appear less associated with such troubles. Spinal diseases at cervical level are frequently associated with postural changes and impaired balance control, related to the major role of sensory inputs during stance and gait. At lower levels, changes are noticed in major scoliosis and may be related to pain intensity in patients with chronic low-back pain. Whatever the initial lesion and the affected level, improvement in clinical or instrumental tests following rehabilitation or brace wearing provides argument for a close relationship between rheumatologic or orthopedic diseases and related impairments in posture and balance control.
The knee joint ligaments contain Ruffini, Pacinian, Golgi, and free-nerve endings with different capabilities of providing the CNS with information about movement and position as well as about noxious events. Skeletomotor neurons (alpha-motoneurons) are known to be influenced only very rarely and weakly from low-threshold mechanoreceptors in the ligaments, while the effects on the tau-muscle-spindle system in the muscles around the knee are so potent that even ligament stretches at very low loads may induce major changes in the responses of the muscle spindle afferents. Since the primary muscle spindle afferents participate in the regulation of muscular stiffness, the receptors in the knee joint ligaments probably contribute, via the tau-muscle-spindle system, to preparatory adjustment (pre-setting) of the stiffness of the muscles around the knee joint, and thereby to the joint stiffness and the functional joint stability.
OSTEOARTHRITIS, "an almost inevitable consequence of aging,"1 is second only to cardiovascular diseases in producing severe chronic disability, and it affects nearly 10 percent of the population over the age of 60.2 This prevalence and its costs — billions of dollars in medications, surgery, and days lost from work3 — account for the growing interest in uncovering the basic mechanisms by which this disease affects human joints.4 5 6 7 8 9 Osteoarthritis can involve axial, or spinal, as well as peripheral joints — those that bear weight (such as the hips and knees) as well as those that do not (such as the distal . . .
The experiments were designed to test two hypotheses and their corollaries: 1. That adaptation of EMG responses to support surface rotations is due to a decrease in the gain of proprioceptively triggered long-loop stretch reflexes (Nashner 1976), and that the adaptation is dependent on a normally functioning vestibular system (Nashner et al. 1982); 2. That EMG responses to rotations are generated primarily by vestibulo-spinal reflexes triggered by head accelerations (Allum and Pfaltz 1985) and comprise a coactivation of opposing leg muscles (Allum and Büdingen 1979). Adaptation with successive dorsi-flexive rotations of the support surface was investigated in the EMG responses of the ankle muscles, soleus (SOL) and tibialis anterior (TA), as well as the neck muscles, trapezius (TRAP) and splenius capitis (SPLEN CAP), both for normal subjects and for patients with bilateral peripheral vestibular deficit. Both normals and patients who first received the stimulus with their eyes open demonstrated decreasing activation at medium latency (ML), that is, with an onset at about 125 ms, and long latency (LL) responses with an onset ca 200 ms. This was the case for both ankle and neck muscles when the EMG response areas for the first 3 and second 7 of 10 trials were compared. Ankle muscle responses in the patients were diminished in area with respect to normals both with the eyes open and with the eyes closed. Ankle torque recordings from the patients were also smaller in amplitude, and these attenuated differently from normal torque responses. Functional coupling of the opposing ML and LL SOL and TA muscle responses was confirmed by the nearly coincident onset times and significantly correlated EMG response areas. At ML, ankle torque was highly correlated with TA activity when the influence of SOL was controlled. At LL, SOL activity was highly correlated with torque when the influence of TA was controlled. The delay of torque adaptation beyond the period of ML activity in normals, but not in the patients was attributed to the proportionally balanced coactivated muscle patterns producing a consistent force output and level of stability in normals. The results indicate that the adaptation in EMG response amplitudes during a sway stabilisation task is not dependent on a normally functioning vestibular system nor on visual inputs but rather appears to be due to a generalized habituation in the postural control system.(ABSTRACT TRUNCATED AT 400 WORDS)
Biomechanical analysis of two-dimensional models composed from roentgenographic pictures and electromyographic analysis on simultaneous isometric contraction exercises of the quadriceps and hamstrings were conducted in 20 healthy adult males. During simultaneous isometric contraction at 5 degrees knee flexion, an anterior drawer force equivalent to 15% of the tension of the quadriceps was exerted to the tibia, and decreased with increased angle of flexion. The mean angle at which this force became zero was 7.4 degrees, with a standard deviation of 5.0 degrees. When the angle increased further, a posterior drawer force to the tibia occurred and gradually increased. Each tension of the quadriceps or hamstrings during maximum simultaneous isometric contraction of the quadriceps and hamstrings was estimated as 30%-60% of that during separate isometric contractions of each muscle. In the early stage of the rehabilitation after the anterior cruciate ligament reconstruction, the simultaneous isometric contraction of the quadriceps and the hamstrings is useful as one of the muscle exercise methods because it can be performed safely with the knee position near the full extension and can generate sufficient muscle force to be an effective exercise.