Association of malalignment, muscular dysfunction, proprioception, laxity and abnormal joint loading with tibiofemoral knee osteoarthritis - a systematic review and meta-analysis

The mediation effects of malalignment on the relation of sex to the risk of incidence tibiofemoral osteoarthritis

OBJECTIVE

To investigate to what extent the higher risk of tibiofemoral radiographic osteoarthritis (TFROA) in females vs. males can be explained by knee malalignment.

DESIGN

Using data from Multicenter Osteoarthritis Study (MOST) and Osteoarthritis Initiative (OAI), we examined the relation of sex to the incident medial and lateral TFROA and performed mediation analyses to assess to what extent varus and valgus malalignments account for sex differences in the incident medial or lateral TFROA.

RESULTS

Of the 3462 knees without medial and lateral TFROA in MOST, the 7-year risks of medial and lateral TFROA were 16.9% and 10.0% in females, and 15.8% and 4.2% in males, respectively. Females had 2.31-fold (95% confidence interval [95% CI]: 1.73 to 3.08) higher incident lateral TFROA than males, and the relative risk (RR) of the indirect effect of sex on lateral TFROA through valgus malalignment was 1.15 (95% CI: 1.09 to 1.20), accounting for 23% of its total effect on lateral TFROA. In OAI (n = 3095 knees), females had 1.54-fold (95% CI: 1.15 to 2.04) higher incident lateral TFROA than males, and RR of the indirect effect of sex on lateral TFROA through valgus malalignment was 1.10 (95% CI: 1.04 to 1.21), accounting for 26% of its total effect on lateral TFROA. No apparent sex difference in the incident medial TFROA was found in MOST (RR = 1.05, 95% CI: 0.89 to 1.25) or OAI (RR = 1.02, 95% CI: 0.84 to 1.19).

CONCLUSION

Females had a higher risk of developing lateral TFROA than males; however, valgus malalignment only modestly explained such a difference.

A synoptic literature review of animal models for investigating the biomechanics of knee osteoarthritis

Osteoarthritis (OA) is a common chronic disease largely driven by mechanical factors, causing significant health and economic burdens worldwide. Early detection is challenging, making animal models a key tool for studying its onset and mechanically-relevant pathogenesis. This review evaluate current use of preclinical in vivo models and progressive measurement techniques for analysing biomechanical factors in the specific context of the clinical OA phenotypes. It categorizes preclinical in vivo models into naturally occurring, genetically modified, chemically-induced, surgically-induced, and non-invasive types, linking each to clinical phenotypes like chronic pain, inflammation, and mechanical overload. Specifically, we discriminate between mechanical and biological factors, give a new explanation of the mechanical overload OA phenotype and propose that it should be further subcategorized into two subtypes, post-traumatic and chronic overloading OA. This review then summarises the representative models and tools in biomechanical studies of OA. We highlight and identify how to develop a mechanical model without inflammatory sequelae and how to induce OA without significant experimental trauma and so enable the detection of changes indicative of early-stage OA in the absence of such sequelae. We propose that the most popular post-traumatic OA biomechanical models are not representative of all types of mechanical overloading OA and, in particular, identify a deficiency of current rodent models to represent the chronic overloading OA phenotype without requiring intraarticular surgery. We therefore pinpoint well standardized and reproducible chronic overloading models that are being developed to enable the study of early OA changes in non-trauma related, slowly-progressive OA. In particular, non-invasive models (repetitive small compression loading model and exercise model) and an extra-articular surgical model (osteotomy) are attractive ways to present the chronic natural course of primary OA. Use of these models and quantitative mechanical behaviour tools such as gait analysis and non-invasive imaging techniques show great promise in understanding the mechanical aspects of the onset and progression of OA in the context of chronic knee joint overloading. Further development of these models and the advanced characterisation tools will enable better replication of the human chronic overloading OA phenotype and thus facilitate mechanically-driven clinical questions to be answered.

Effect of strength training on knee proprioception in patients with knee osteoarthritis: A systematic review and meta-analysis

Proprioception is significantly impaired in knee osteoarthritis (KOA), contributing to reduced functionality. Strength training (ST) is essential in KOA by improving muscle strength, although it may also be effective in improving proprioception. The purpose was to determine the effect of ST on knee proprioception in KOA patients. Pubmed, CINAHL, Scopus, WOS, and PEDro were searched for randomized controlled trials (RCTs) (inception to March 2023). Comparisons for ST were physical exercise different from ST, non-exercise-based interventions, and no intervention. Methodological quality was assessed using the PEDro scale, and risk of bias (RoB) using the Cochrane tool. Meta-analyses were performed by comparison groups using the standardized mean difference (SMD) (Hedge's g) with random effects models, also considering subgroups by proprioception tests. Finally, six RCTs were included. The mean PEDro score was 6.3, and the highest proportion of biases corresponds to performance, selection, and detection. The meta-analysis indicated that only when compared with non-intervention, ST significantly improved knee proprioception for the joint position sense (JPS) (active + passive), JPS (passive), and threshold to detect passive motion (TTDPM) subgroups (g ​= ​-1.33 [-2.33, -0.32], g = ​-2.29 [-2.82, -1.75] and g ​= ​-2.40 [-4.23, -0.58], respectively). However, in the knee JPS (active) subgroup, ST was not significant (g ​= ​-0.72 [-1.84, 0.40]). In conclusion, ST improves knee proprioception compared to non-intervention. However, due to the paucity of studies and diversity of interventions, more evidence is needed to support the effectiveness of ST. Future RCTs may address the limitations of this review to advance knowledge about proprioceptive responses to ST and contribute to clinical practice.

The test-retest reliability and concurrent validity of 360° turn test in patients with knee osteoarthritis

PURPOSE

The aim of this study is to determine whether the 360° turn test is a reliable and valid evaluator that can be used to assess dynamic balance in patients with early (radiographic grades I and II) and advanced (radiographic grades III and IV) knee osteoarthritis.

MATERIALS AND METHODS

This study is a methodological research. For the test time and step count of 360° turn test; test-retest reliability were determined by calculating the intraclass correlation coefficient and concurrent validity in patients with knee osteoarthritis was investigated by correlation with the timed up and go test time.

RESULTS

The final analysis was made on 117 participants. The intraclass correlation coefficient values for the test time and step count of 360° turn test in patients with early knee osteoarthritis are 0.931 and 0.902, respectively, while they are 0.923 and 0.943 in patients with advanced knee osteoarthritis. The Pearson correlation coefficients between the time and step count of 360° turn test and the test time of the timed up and go test in patients with early knee osteoarthritis, respectively; while they are 0.547 and 0.388, the correlation in patients with advanced knee osteoarthritis are 0.697 and 0.700, respectively (p < 0.01).

CONCLUSIONS

The 360° turn test is a evaluator that has excellent test-retest reliability and moderate to strong concurrent validity in patients with both early and advanced knee osteoarthritis and can be used in the assessment of dynamic balance in this population.

Clinical and biomechanical characteristics of responders and non-responders to insoles in individuals with excessive foot pronation during walking

This study aimed to identify the clinical and biomechanical factors of subjects with excessive foot pronation who are not responsive (i.e., "non-responders") to medially wedged insoles to increase knee adduction external moment. Ankle dorsiflexion range of motion, forefoot-shank alignment, passive hip stiffness, and midfoot passive resistance of 25 adults with excessive bilateral pronation were measured. Also, lower-limb angles and external moments were computed during walking with the participants using control (flat surface) and intervention insoles (arch support and 6° medial heel wedge). A comparison between "responders" (n = 34) and "non-responders" (n = 11) was conducted using discrete and continuous analyses. Compared with the responders, the non-responders had smaller forefoot varus (p = 0.014), larger midfoot passive internal torque peak (p = 0.005), and stiffness measured by the torsimeter (p = 0.022). During walking, non-responders had lower angle peaks for forefoot eversion (p = 0.001), external forefoot rotation (p = 0.037), rearfoot eversion (p = 0.022), knee adduction (p = 0.045), and external hip rotation (p = 0.022) and higher hip internal rotation angle peak (p = 0.026). Participants with small forefoot varus alignment, large midfoot passive internal torque, stiffness, small knee valgus, hip rotated internally, and foot-toed-in during walking did not modify the external knee adduction moment ("non-responders"). Clinicians are advised to interpret these findings with caution when considering the prescription of insoles. Further investigation is warranted to fully comprehend the response to insole interventions among individuals with specific pathologies, such as patellofemoral pain and knee osteoarthritis (OA).

Influence of patients' preoperative expectations on postoperative outcomes after total knee or hip arthroplasty: a systematic review

Purpose

The association between preoperative expectations and treatment outcomes in total hip arthroplasty (THA) or total knee arthroplasty (TKA) is still unclear. Therefore the aim is to examine the association between preoperative outcome expectations, process expectations, and self-efficacy, and the postoperative outcomes overall outcome, pain, function, stiffness, satisfaction, and quality of life following THA/TKA.

Methods

A systematic review with narrative synthesis was conducted. PubMed, EMBASE, PsycINFO, CINAHL and Cochrane Library were searched from inception to October 17, 2022. Included were prospective longitudinal cohort studies published in English, German, or Dutch, with an adult population undergoing THA/TKA, and including at least one measure of preoperative expectations and the postoperative outcomes mentioned earlier. Two independent reviewers screened the retrieved articles for eligibility, a third solved disagreements. Risk of bias (RoB) was assessed using the QUIPS tool.

Results

Of the 50 included studies, 38 had high RoB and 12 moderate RoB. Unadjusted results suggest a positive association between preoperative outcome expectations and overall outcome in the medium and long term, and between self-efficacy and change in 'overall outcome' in the long term. Adjusted results suggest positive associations between outcome expectations and function and between self-efficacy and overall outcome in the medium term, and for outcome expectations with pain and change in pain, respectively, and self-efficacy and stiffness in the long term.

Conclusions

Preoperative expectations show a possible positive association with specific outcome measures, such as pain or function. For future research, it is advised to link matching specific expectations with specific outcomes.

Extracorporeal Shock Wave Therapy as Regenerative Medicine in Knee Osteoarthritis: Pre-Experiment for Matrix Metalloproteinase-3 Evaluation

BACKGROUND

Knee osteoarthritis (KOA) is currently treated by regenerative therapies that aim to inhibit arthritic degeneration. Extracorporeal shock wave therapy (ESWT) is one of the physical regenerative approaches used for KOA management. However, little is known regarding the impact of shock wave treatment on matrix metalloproteinase-3 (MMP-3), which is one of the enzymes mediating cartilage degradation.

OBJECTIVES

To evaluate the effect of ESWT on MMP-3 levels and pain intensity in patients with KOA.

METHODS

Fourteen patients diagnosed with Kellgren Lawrence, grades 2 and 3 KOA were recruited for the study. ESWT piezo shockwave was applied once a week for six weeks. MMP-3 levels in the blood were measured pre-test, mid-test (three weeks after therapy) and post-test (one week after the last session) by enzyme-linked immunosorbent assay (ELISA). The perceived pain was recorded at each session by the Wong Becker Face Scale.

RESULTS

The median pre-test, mid-test and post-test MMP-3 levels were 19.92 ng/mL, 15.89 ng/mL and 18.82 ng/mL, respectively, and there were significant differences between the pre-test and mid-test, and the pre-test and post-test values (p < 0.05). The pain scores also decreased significantly over the period of intervention.

CONCLUSION

MMP-3 levels decreased significantly in KOA patients after ESWT, and the decline was most obvious after 3 weeks of therapy. Therefore, EWST should be considered as a suitable treatment option for KOA.

Association between quadriceps tendon elasticity and neuromuscular control in individuals with knee osteoarthritis

BACKGROUND

Knee osteoarthritis is a complex condition with established risk factors such as female sex, increasing age and body mass index, reduced quadriceps muscle strength and knee injury. Despite known associated risks, the role and behaviour of knee tendons in knee osteoarthritis remains unclear. This study explores the association between quadriceps tendon elasticity, muscle strength, neuromuscular control, proprioception and patient reported outcome measures in individuals with knee osteoarthritis.

METHODS

Adults with doctor-diagnosed knee osteoarthritis were recruited from rheumatology clinics and general practitioner practices. Quadriceps tendon elasticity was estimated using sonoelastography. Neuromuscular control data including electromyography, electromechanical delay and proprioception measures were included. Participants completed the Knee Injury and Osteoarthritis Outcome Score. Associations between elasticity values, physical and neuromuscular data and patient reported outcomes scores were evaluated using Spearman's correlations.

FINDINGS

Thirty-nine adults with knee osteoarthritis were eligible for inclusion. Increased tendon stiffness was negatively associated with rate of force development, time to half peak force and passive positioning sense in individuals with knee osteoarthritis. Similarly, patient reported symptoms were found to be associated with sonoelastography findings with moderate-strong associations observed between activities of daily living sport and recreation, pain and symptoms and between neuromuscular control measures and muscle strength.

INTERPRETATION

Stiffer tendon identified within the knee osteoarthritis group was associated with reduced neuromuscular control and knee joint proprioception. Stiffer quadriceps tendon may contribute to the poorer reported symptoms by knee osteoarthritis individuals. These findings may impact disease symptoms and progression which could lead to further joint impairment.

Muscle strength and osteoarthritis of the knee: a systematic review and meta-analysis of longitudinal studies

OBJECTIVE

To evaluate the sex-specific association between low knee extensor and flexor muscle strength and the risk of knee structural worsening.

MATERIALS AND METHODS

Systematic searches in five databases identified longitudinal studies (≥ 1 year follow-up) reporting an association between knee extensor or flexor strength and structural decline in individuals with, or at risk of, knee osteoarthritis. Results were pooled for tibiofemoral and patellofemoral osteoarthritis worsening (and stratified by sex/gender where possible) using a random-effects meta-analysis estimating the risk ratio and 95% confidence interval or a best-evidence synthesis. Risk of bias and overall certainty of evidence were assessed.

RESULTS

Fourteen studies were included with participants (mean age 27-72 years) with osteoarthritis (n = 8), at risk of osteoarthritis (n = 3), or a combination with, or at risk of, osteoarthritis (n = 3). Low knee extensor strength was associated with an increased risk of worsening tibiofemoral (12 studies: RR 1.18, 95% CI 1.04 to 1.35) and patellofemoral osteoarthritis (4 studies: RR 1.62, 95% CI 1.01 to 2.61). Significant associations between low knee extensor strength and worsening tibiofemoral osteoarthritis were observed for women (4 studies: RR 1.25, 95% CI 1.04 to 1.51) but not men (4 studies: RR 1.10, 95% CI 0.87 to 1.39). Low knee flexor strength increased the risk of worsening tibiofemoral osteoarthritis (5 studies: RR 1.16, 95% CI 1.07 to 1.26). Ten studies were high risk of bias, and all estimates were graded as very low certainty of evidence.

CONCLUSION

Low knee extensor and flexor strength increased the risk of worsening tibiofemoral osteoarthritis. Low knee extensor strength increased the risk of worsening patellofemoral osteoarthritis. The relationship between low knee extensor strength and worsening tibiofemoral osteoarthritis may be modified by sex/gender.

Can exercise interventions reduce external knee adduction moment during gait? A systematic review and meta-analysis

BACKGROUND

An increased external knee adduction moment has been identified as a factor contributing to the progression of medial knee osteoarthritis. Interventions that reduce knee adduction moment may help prevent knee osteoarthritis onset and progression. While exercise interventions have been commonly used to treat knee osteoarthritis, whether exercises can modulate knee adduction moment in knee osteoarthritis patients remains unknown. This systematic review and meta-analysis aimed to determine if exercise interventions are effective in reducing knee adduction moment during gait.

METHODS

Study reports published through May 2023 were screened for pre-specified inclusion/exclusion criteria. Nine studies met the eligibility criteria and yielded 24 effect sizes comparing the reduction in knee adduction moment of the exercise intervention groups to the control groups. Moderator/experimental variables concerning characteristics of the exercise interventions and included subjects (e.g., sex, BMI, type of exercise, muscle group targeted, training volume, physical therapist supervision) that may contribute to variation among studies were explored through subgroup analysis and meta-regression.

FINDINGS

The effect of exercise intervention on modulating knee adduction moment during gait was no better than control (ES = -0.004, P = 0.946). Sub-group analysis revealed that the effect sizes of studies containing only females (positive exercise effect) were significantly greater than studies containing both males and females.

INTERPRETATION

Exercise may not be effective in reducing knee adduction moment during gait. Clinicians aiming to decrease knee adduction moment in patients with medial knee osteoarthritis should consider alternative treatment options. Exploring the underlying mechanism(s) regarding a more positive response to exercises in females may help design more effective exercise interventions.

The effects of exercise training on knee repositioning sense in people with knee osteoarthritis: a systematic review and meta-analysis of clinical trials

OBJECTIVE

Osteoarthritis (OA) of the knee is one of the most common global joint disorders, especially in aging population, and is among leading health-related concerns of societies. Therefore, this systematic review and meta-analysis was done to investigate the results related to the effects of exercise interventions on knee repositioning sense in patients with knee OA.

METHODS

An extensive search was independently performed in electronic databases including PubMed, MEDLINE, Web of Science, SCOPUS, and Google Scholar, to identify randomized clinical trials (RCTs) conducted on knee OA and to evaluate knee repositioning sense before and after different exercise interventions. After extracting relevant data from eligible studies, results of the studies were pooled using a random-effects model of meta-analysis. The Physiotherapy Evidence Database (PEDro) of clinical trials was used for quality assessment of eligible studies.

RESULTS

Among 2702 studies identified in the initial search, 17 studies were eligible for final systematic review and meta-analysis. The results showed that the patients who participated in different exercise interventions had significantly less knee repositioning error (mean differences: -1.141 degrees (95%CI: -1.510, -0.772, P < .001) compared to those who did not undergo exercise interventions. The eligible studies exhibited publication bias (Intercept: -6.69, P = .002), and the data showed significant heterogeneity (I2 = 85.633%, Q = 153.125, P < .001). Moreover, meta regression showed more prolonged exercise duration might have more effects on knee repositioning error (Coefficient=-0.860, 95% CI=-1.705, -0.016, Z=-2.00, P = .045).

CONCLUSION

There is strong evidence that exercise interventions may effectively reduce knee repositioning error. Moreover, it seems that more prolonged exercise duration may be associated with the greater effect size.

Risk factors for the long-term incidence and progression of knee osteoarthritis in older adults: role of nonsurgical injury

Background

For one of the most chronic medical conditions, osteoarthritis, uncertainties remain on the impact of injury chronology, the role of repeat injury on the incidence/progression of this disease and the need for knee arthroplasty.

Objectives

To explore, in an older adult population, how nonsurgical knee injuries relate to osteoarthritis incidence/progression and the weight of independent risk factors for arthroplasty.

Design

A cohort study design evaluates the long-term impact of injuries on knee osteoarthritis outcomes.

Methods

Knees with no prior injury (n = 6358) and with at least one injury (n = 819) ⩽20 years before study inclusion were from the Osteoarthritis Initiative cohort. Sociodemographic, clinical and structural [X-ray, magnetic resonance imaging (MRI)] data at study inclusion and changes within 96 months were analysed. Statistics included a mixed model for repeated measurements, generalized estimating equations and multivariable Cox regression with covariates.

Results

At inclusion, knees with prior injury demonstrated greater incidence and severity of osteoarthritis (p ⩽ 0.001). At 96 months, there was a greater increase in symptoms [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, p = 0.002], joint space width (JSW, p = 0.039) loss, medial cartilage volume loss (CVL, p ⩽ 0.001) and bone marrow lesion size (BML, p ⩽ 0.049). Knees with/without injury at inclusion but with new ones over time had a pronounced increase in symptoms (all WOMAC scores, p ⩽ 0.001), JSW loss, lateral (without) and medial CVL, lateral (without) and medial meniscal extrusion and medial BML (without; all p ⩽ 0.030). Levels of lateral and medial meniscal extrusion (without) and symptoms (with/without; all WOMAC scores, p ⩽ 0.001) were all accentuated with a repeated new injury. Risk factors associated with the highest knee arthroplasty occurrence are new meniscal extrusion and new injury (p ⩽ 0.001).

Conclusion

This study highlights the importance of nonsurgical knee injury in older adults as an independent risk factor for knee osteoarthritis and arthroplasty. These data will be beneficial in clinical practice as they will help identify individuals at greater risk of significant disease progression and worst disease outcomes for a customized therapeutic approach.

Effect of autogenous osteochondral mosaicplasty on the balance control of patients with cartilage defects of the knee: a pilot study

BACKGROUND

Autogenous osteochondral mosaicplasty (AOM) is a widely used optimal surgical technique for cartilage repair in young patients with focal articular cartilage defects. However, the alterations in balance control in these patients after AOM have not been sufficiently investigated. This study aimed to compare different balance control performances between the patients with knee cartilage defects and healthy controls before and after AOM, as well as evaluate the influence of AOM on balance control in these patients.

METHODS

Static posturographic tests were performed in twenty-four patients who were scheduled for AOM two weeks pre-, three months, and one year postoperatively, along with thirty matched controls, respectively. All participants underwent posturography under four standing conditions: eyes open and closed, without and with foam support to assess the balance control ability. Subsequently, patient-reported outcome measures (PROMs) were synchronously obtained and analyzed.

RESULTS

Compared to the control subjects, less efficient balance control was observed in study patients at three testing phases (p < 0.05), whereas no alterations in postural control were visible in these patients within a year following AOM (p > 0.05). Significant improvements were found in all PROMs such as the International Knee Documentation Committee, the Lysholm Knee Score, and the visual analogue scale in the study patients postoperatively (p < 0.01).

CONCLUSION

The results indicated that patients with knee cartilage defects have a prominent balance control deficit compared to healthy individuals. Furthermore, AOM does not improve balance control in these patients for at least one year postoperatively, and more effective approaches for postural regulation are required for the management of cartilage defect patients.

Sensory-motor training versus resistance training in the treatment of knee osteoarthritis: A randomized controlled trial

OBJECTIVE

To compare the effectiveness of sensory-motor training and resistance training in patients with knee osteoarthritis.

DESIGN

Randomized controlled trial.

SETTING

Istanbul University, Department of Physiotherapy and Rehabilitation.

SUBJECTS

Forty-eight participants with knee osteoarthritis.

INTERVENTIONS

Following baseline assessment, participants were randomly allocated to sensory-motor training (n  =  24) and resistance training (n = 24). Both groups received training three times a week for 8 weeks.

MAIN MEASURES

The primary outcome measure was the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The secondary outcome measures were pain level, muscle strength, proprioception, range of motion, quality of life, and patient satisfaction with treatment. Patients were assessed before and after four- and eight-week interventions.

RESULTS

There was no significant difference between the groups' total WOMAC scores after four- and eight-week interventions (respectively, p = 0.415, p = 0.828). There was a significant improvement in pain level during movement and in the energy subscale SF-36 for resistance training after the four-week intervention (respectively, p = 0.012, p = 0.007). After the eight-week intervention, a significant difference was noted in favor of resistance training in the secondary outcome measure quality of life (QoL). No significant difference was found in other secondary outcomes.

CONCLUSIONS

At the end of the treatment, it was observed that sensory-motor training had a similar effect in the treatment of knee osteoarthritis symptoms to resistance training. These findings may suggest that sensory-motor training is an effective new method to treat patients with knee osteoarthritis.

Knee Osteoarthritis: Epidemiology, Pathogenesis, and Mesenchymal Stem Cells: What Else Is New? An Update

Osteoarthritis (OA) is a chronic disease and the most common orthopedic disorder. A vast majority of the social OA burden is related to hips and knees. The prevalence of knee OA varied across studies and such differences are reflected by the heterogeneity of data reported by studies conducted worldwide. A complete understanding of the pathogenetic mechanisms underlying this pathology is essential. The OA inflammatory process starts in the synovial membrane with the activation of the immune system, involving both humoral and cellular mediators. A crucial role in this process is played by the so-called “damage-associated molecular patterns” (DAMPs). Mesenchymal stem cells (MSCs) may be a promising option among all possible therapeutic options. However, many issues are still debated, such as the best cell source, their nature, and the right amount. Further studies are needed to clarify the remaining doubts. This review provides an overview of the most recent and relevant data on the molecular mechanism of cartilage damage in knee OA, including current therapeutic approaches in regenerative medicine.

What Influences Proprioceptive Impairments in Patients with Rheumatic Diseases? Analysis of Different Factors

Rheumatic diseases lead to postural problems, which increase the risk of falls and lead to greater disability. The aim of the present work is to evaluate posture disorders in patients with osteoarthritis (OA) and rheumatoid arthritis (RA), as well as to evaluate the influence of other factors. A total of 71 subjects were enrolled in this study. Joint position sense (JPS) and the functional assessment of proprioception on a balance platform for both lower limbs were examined. The Average Trace Error (ATE), test time (t), and Average Platform Force Variation (AFV) were calculated. Additionally, an equilibrium test was carried out in the one-legged standing position (Single Leg Stance-SLS). The results were compared in several ways and revealed the following: (1) A JPS of 10° plantar flexion in RA obtained significantly worse results when repeating the movement than OA; the ATEs were significantly lower in RA; and RA needed more support during SLS assessment. (2) RA patients with higher DAS28 had statistically significantly higher values in JPS, with 5° plantar flexion and 10° dorsal flexion, SLS assessment, and stabilometric rates. A statistically significant correlation between DAS28 and RA was found in a JPS of 10° plantar flexion. The VAS ruler demonstrated a significant moderate correlation with t. (3) Patients who experienced at least one fall demonstrated higher JPS and t. Our study shows that proprioception is the most influenced by the nature of the disease and the level of disease activity. We can see that the stability and balance functions are also greatly influenced by the patient's falling experience and the level of pain. These findings may be useful in designing an optimal proprioception-enhancing movement training plan.

Changes in the femoral varus and rotational profiles are correlated in women with varus osteoarthritic lower limbs

INTRODUCTION

Previous studies have reported the relationship between coronal alignment of the lower limbs and the rotational profile of the femur and tibia. However, the relationship between coronal alignment of the femur and tibia and their rotational profiles in patients with varus osteoarthritic knees is unclear.

METHODS

One hundred women with varus osteoarthritic knees (varus OA group) and 50 women with neutrally aligned lower limbs without osteoarthritis (non-OA group) were evaluated retrospectively. The coronal alignment and rotational profile of the femur and tibia were evaluated, and the correlation between coronal alignment and rotational profile was analyzed, respectively.

RESULTS

The femoral anteversion, posterior condylar angle of the distal femur, and tibial torsion were significantly smaller in the varus OA group than in the non-OA group. In the varus OA group, the femoral anteversion and rotational profile of the distal femur had significantly negative correlations with the degree of femoral varus, while tibial torsion was not related to the degree of tibial varus. In the non-OA group, there was no relationship between coronal alignment and rotational profiles of the femur and tibia in both the varus OA and non-OA groups.

CONCLUSION

Femoral anteversion and the rotational profile of the distal femur were negatively correlated with the degree of femoral varus in Asian women with varus osteoarthritic knees. This study enhanced the understanding of the relationship between changes in coronal alignment of the femur and tibia and their rotational profiles in patients with varus osteoarthritic lower limbs, although this study was limited by the small sample sizes and methodological quality.

[MRI case series shows the development of medial gonarthrosis after medial meniscus tear and partial medial meniscectomy]

Meniscal injuries lead to changes in pressure distribution in the knee joint. The risk of developing gonarthrosis increases by the amount of resected meniscal tissue. Based on 4 MRI examinations conducted over an 8‑year time period, the present case report shows the progress of cartilage degeneration after a traumatic medial meniscus lesion and subsequent partial meniscus resection in a 46-year-old male patient. Congenital or accident-independent risk factors, such as a varus limb deformity must be considered during a medical report.

Factors associated with self-rated difficulty to descend stairs in persons with knee osteoarthritis

BACKGROUND

Difficulty descending stairs is common in persons with knee osteoarthritis (OA). Clinically, it is important to know if and how this is explained by objectively measured difficulty to descend stairs, muscle weakness, pain, fear of movement, or knee joint status.

OBJECTIVE

To identify the potential of these factors to explain self-reported difficulty descending stairs.

DESIGN

Cross sectional, case-control.

SETTING

Hospital outpatient and physiotherapy clinic.

PARTICIPANTS

Twenty-eight men and women with knee OA (age 62.2 SD 5.9 years) and 31 controls (age 50.0 SD 8.5 years).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Using multivariate statistics, group comparisons were made for lower extremity kinematics (incorporating hip, knee, and ankle angles) and stance time in stair descent and lower extremity muscle strength. Then, a stepwise linear regression analysis was performed within the OA group to explain self-reported difficulties in stair descent where pain, kinesiophobia, radiographic signs, and outcomes that differed from controls for stair-descent kinematics and muscle strength were independent variables.

RESULTS

Multivariate statistics showed that the OA group displayed different all-over lower extremity kinematics (F_8,42 = 2.44 p = .029, η²  = 0.32) and a longer stance time (F_3,50 = 6.46; p = .001, η²  = 0.28) in stair descent and lower muscle strength (F_7,47 = 2.39; p = .035, η²  = 0.26) compared to controls. Regression analysis within the OA group to explain self-rated difficulties to descend stairs showed that the strongest association with kinesiophobia (ß = 0.607, p = .001) that combined with pain last week and radiographic signs explained almost 100% (ß = 0.972). Stair descent kinematics and strength variables that differed between groups did not explain self-rated difficulties to descend stairs.

CONCLUSION

Kinesiophobia and pain rather than stair-descent kinematics and reduced muscle-strength explained self-rated difficulties in stair descent in the OA group.

Effect of functional weightbearing versus non-weightbearing quadriceps strengthening exercise on contact force in varus-malaligned medial knee osteoarthritis: A secondary analysis of a randomized controlled trial

BACKGROUND

Knee osteoarthritis progression may be related to altered knee loads, particularly in those with varus malalignment. Using randomized controlled trial data, this secondary analysis of complete datasets (n = 67) compared the effects of a functional weightbearing (WB) and non-weightbearing quadriceps strengthening exercise (NWB) program on measures of medial tibiofemoral joint contact force (MTCF) during walking.

METHODS

Participants aged ≥50 years and with medial knee osteoarthritis and varus malalignment were randomly allocated to a 12-week, home-based, physiotherapist-prescribed exercise program comprised of WB exercises (n = 31), or NWB exercise (n = 36). Three-dimensional lower-body motion, ground reaction forces, and surface electromyograms from six lower-limb muscles were acquired during walking at baseline and at 12-weeks follow-up. An electromyogram-informed neuromusculoskeletal model estimated bodyweight (BW) normalized MTCF (peak and impulse), including external and muscular contributions to MTCF.

RESULTS

There was no between-group difference in the change in peak MTCF (-0.02 [-0.12, 0.09] BW) or MTCF impulse (-0.01 [-0.06, 0.03] BW·s). There was a between-group difference in the muscle contribution to peak MTCF (-0.08 [-0.15, -0.00] BW) and MTCF impulse (-0.04 [-0.08, -0.00] BW·s), whereby the muscle contribution reduced more in the NWB group over time compared to the WB group. There was also a between group-difference in the external contribution to peak MTCF (0.09 [0.01, 0.18] BW), but this reduced more in the WB group than in the NWB group.

CONCLUSIONS

Our findings suggest no difference in MTCF between the two exercise programs, but differences in the contribution to MTCF between the two exercise programs were observed in those with medial knee osteoarthritis and varus malalignment.

Environmental Risk Factors for Osteoarthritis: The Impact on Individuals with Knee Joint Injury

Osteoarthritis is a debilitating chronic condition involving joint degeneration, impacting over 300 million people worldwide. This places a high social and economic burden on society. The knee is the most common joint impacted by osteoarthritis. A common cause of osteoarthritis is traumatic joint injury, specifically injury to the anterior cruciate ligament. The purpose of this review is to detail the non-modifiable and modifiable risk factors for osteoarthritis with particular focus on individuals after anterior cruciate ligament injury. After reading this, health care providers will better comprehend the wide variety of factors linked to osteoarthritis.

The sensorimotor theory of pathological pain revisited

Harris (1999) proposed that pain can arise in the absence of tissue damage because changes in the cortical representation of the painful body part lead to incongruences between motor intention and sensory feedback. This idea, subsequently termed the sensorimotor theory of pain, has formed the basis for novel treatments for pathological pain. Here we review the evidence that people with pathological pain have changes to processes contributing to sensorimotor function: motor function, sensory feedback, cognitive representations of the body and its surrounding space, multisensory processing, and sensorimotor integration. Changes to sensorimotor processing are most evident in the form of motor deficits, sensory changes, and body representations distortions, and for Complex Regional Pain Syndrome (CRPS), fibromyalgia, and low back pain. Many sensorimotor changes are related to cortical processing, pain, and other clinical characteristics. However, there is very limited evidence that changes in sensorimotor processing actually lead to pain. We therefore propose that the theory is more appropriate for understanding why pain persists rather than how it arises.

Risk factors associated with the occurrence of total knee arthroplasty in patients with knee osteoarthritis: a nested case–control study

Objectives:

The aim of this study was to investigate changes over time in osteoarthritis risk factors most closely associated with the occurrence of total knee arthroplasty (TKA). We hypothesize that the robustness of a longitudinal case–control study will provide new information on the association between changes in various clinical and structural parameters in different time frames before TKA.

Methods:

Cases (195; TKA after cohort entry) and controls (468) matched for age, gender, income, WOMAC pain, Kellgren–Lawrence grade and follow-up duration were from the Osteoarthritis Initiative cohort. Associations between changes in sociodemographic, clinical, imaging and osteoarthritis therapies with the occurrence of TKA were performed using conditional logistic regression analyses.

Results:

Worsening of WOMAC scores (cOR 1.02–1.20, p ⩽ 0.012), KOOS (1.02–1.04, p ⩽ 0.014), knee injuries sustained in the previous 30–40 years (women 2.70, p = 0.034) and valgus alignment (1.10, p = 0.052) were associated with the occurrence of TKA. Also associated with TKA was cartilage volume loss in the lateral (overall 1.76, p = 0.025; women 1.93, p = 0.047) and medial compartments (⩾10%, overall 1.54, p = 0.027; men 2.34, p = 0.008), occurrence of medial meniscal extrusion (overall 1.77, p = 0.046; men 2.86, p = 0.028), and increase in bone marrow lesions (BMLs) for women (1.09, p = 0.048). The association of risk factors with TKA was reinforced when both an increase in WOMAC pain and cartilage volume loss (1.85, p = 0.001) were combined. Pain medication usage, mainly narcotics and intra-articular steroid injections (IASI), was also associated with TKA, with no impact on changes in cartilage loss or structure.

Conclusion:

This study provides new information about gender differences in risk factors associated with the occurrence of TKA. Worsening of valgus alignment, cartilage volume loss in the lateral compartment, BMLs and older injuries are important risk factors in women, while medial compartment cartilage loss and meniscal extrusion are in men. The use of pain medication and IASI although associated was found not causal with TKA.

The effect of an ankle-foot orthosis on tibiofemoral motion during step-up and step-down in healthy adults

BACKGROUND

Solid ankle-foot orthoses (SAFOs) are frequently prescribed in conditions such as cerebral palsy and stroke. Although gait is improved in the short term, long-term effects of limiting ankle and foot motion during functional activities on joints such as the knee have not been investigated. Our study purpose was to compare tibiofemoral (TF) motion in shoe and SAFO conditions in healthy adults to inform future studies in clinical populations.

METHODS

A custom-made device using electromagnetic sensors was used to collect three-dimensional TF rotation data while 29 healthy adult participants (female participants = 19, age = 24.4 ± 4.5 years) performed step-up/step-down in shoe and SAFO conditions.

RESULTS

In the SAFO condition during step-up, extent of motion was greater in frontal and transverse planes and less in the sagittal plane. Discrete values at 0%-10% of the cycle in sagittal, 50%-100% in frontal, and 40%-100% in transverse planes were statistically different, producing more abduction and external rotation. In the SAFO condition during step-down, extent of motion was significantly greater in the frontal and transverse planes. Discrete values were statistically different in 40%-60% of the cycle in sagittal, 0%-30% and 70%-90% in frontal, and 0%-30% and 70%-90% in transverse planes, producing more abduction and external rotation in the first half of the cycle and more adduction and internal rotation in the second half of the cycle.

CONCLUSIONS

An SAFO affects triplanar TF kinematics in healthy adults during step-up/step-down. Future investigations into ankle-foot orthosis prescription and TF motion in clinical populations will facilitate optimal ankle-foot orthosis prescription and knee function in the long term.

Analysis of Clinical Efficacy of Clearing Heat and Dispelling Paralysis Soup in the Treatment of Osteoarthritis of the Knee Joint and Its Effect on Patients' Motor Function

OBJECTIVE

To investigate the effects of clearing heat and dispelling paralysis soup for osteoarthritis of the knee joint on the motor function of the knee joint and the level of inflammation of the organism in patients.

METHODS

One hundred and sixteen patients with knee osteoarthritis admitted from January 2020 to May 2021 were selected and randomly divided into 2 groups, 58 cases in the control group were treated with loxoprofen sodium dispersible tablets, and 58 cases in the experimental group were treated with Qinghe dispel paralysis soup on the basis of the control group and the patients' balance ability analysis, gait parameter change analysis, VAS, JOA, AIMS2-SF scale assessment, and serum index. The treatment effects of the two treatment regimens were analyzed by testing.

RESULTS

The anterior-posterior axis, left-right axis, A2-A6, A4-A8, and circumferential axis of the experimental group were lower than those of the control group after treatment (P < 0.05); the step length of the experimental group was higher than that of the control group after treatment (P < 0.05), and there were no significant differences in step speed, double-support phase, and step width (P > 0.05), but both groups improved significantly compared with those before treatment (P < 0.05); the VAS score of the experimental group was lower than that of the control group after treatment. The VAS scores of the experimental group were lower than those of the control group, and the scores of JOA and AIMS2-SF were higher than those of the control group (P < 0.05); the levels of TIMP-1 in the experimental group were higher than those in the control group, and the levels of TNF-α, TLR4, MMP-3, and IL-1 were lower than those in the control group after treatment (P < 0.05); there was no significant difference in the incidence of adverse reactions between the two groups during treatment (P > 0.05), and the efficiency of the experimental group was higher than that of the control group (P < 0.05).

CONCLUSION

Combined treatment with Qinghe dispel paralysis soup can better promote the recovery of balance, improve motor ability, and reduce the development of inflammation in the organism, with high safety and effectiveness.

Joint Damage and Neuropathic Pain in Rats Treated With Lysophosphatidic Acid

Joint pain is a complex phenomenon that involves multiple endogenous mediators and pathophysiological events. In addition to nociceptive and inflammatory pain, some patients report neuropathic-like pain symptoms. Examination of arthritic joints from humans and preclinical animal models have revealed axonal damage which is likely the source of the neuropathic pain. The mediators responsible for joint peripheral neuropathy are obscure, but lysophosphatidic acid (LPA) has emerged as a leading candidate target. In the present study, male and female Wistar rats received an intra-articular injection of LPA into the right knee and allowed to recover for 28 days. Joint pain was measured by von Frey hair algesiometry, while joint pathology was determined by scoring of histological sections. Both male and female rats showed comparable degenerative changes to the LPA-treated knee including chondrocyte death, focal bone erosion, and synovitis. Mechanical withdrawal thresholds decreased by 20-30% indicative of secondary allodynia in the affected limb; however, there was no significant difference in pain sensitivity between the sexes. Treatment of LPA animals with the neuropathic pain drug amitriptyline reduced joint pain for over 2 hours with no sex differences being observed. In summary, intra-articular injection of LPA causes joint degeneration and neuropathic pain thereby mimicking some of the characteristics of neuropathic osteoarthritis.

Guided growth: indications and techniques for correction of knock knees and bowlegs

PURPOSE OF REVIEW

Lower extremities axis alterations are a frequent cause for consultation in the medical practice of the care of paediatric patients. When it corresponds to pathological situations, guided growth surgery has been positioned as a possibility of well tolerated, reproducible and predictable resolution. For this reason, its use has increased significantly in recent years. In this review, its current indications, preoperative study, results and complications described in the updated literature will be discussed.

RECENT FINDINGS

The success of the technique remains high in the current literature, expanding the technique to other segments and disorders, and describing new ways of performing tension band with sutures. In addition, there is an increase in its incidence and a decrease in the associated hospitalized days, which can associate with techniques of lower morbidity.

SUMMARY

As guided growth surgery allows for successful correction of axis alterations, to achieve this, it is important to know the main indications, preoperative analysis and theoretical bases on which this technique is based, to carry it out in an adequate and timely manner, seeking an adequate resolution of the child's problem.

Epidemiology of osteoarthritis

OBJECTIVE

To summarize the current state of the evidence regarding osteoarthritis (OA) prevalence, incidence and risk factors at the person-level and joint-level.

DESIGN

This was a narrative review that took a comprehensive approach regarding inclusion of potential risk factors. The review complements prior reviews of OA epidemiology, with a focus on new research and emerging topics since 2017, as well as seminal studies.

RESULTS

Studies continue to illustrate the high prevalence of OA worldwide, with a greater burden among older individuals, women, some racial and ethnic groups, and individuals with lower socioeconomic status. Modifiable risk factors for OA with the strongest evidence are obesity and joint injury. Topics of high interest or emerging evidence for a potential association with OA risk or progression include specific vitamins and diets, high blood pressure, genetic factors, metformin use, bone mineral density, abnormal joint shape and malalignment, and lower muscle strength/quality. Studies also continue to highlight the heterogenous nature of OA, with strong interest in understanding and defining OA phenotypes.

CONCLUSIONS

OA is an increasingly prevalent condition with worldwide impacts on many health outcomes. The strong evidence for obesity and joint injury as OA risk factors calls for heightened efforts to mitigate these risks at clinical and public health levels. There is also a need for continued research regarding how potential person- and joint-level risk factors may interact to influence the development and progression of OA.

Effectiveness and safety of massage for chronic pain in patients with knee osteoarthritis: A protocol for systematic review and meta-analysis

BACKGROUND

Chronic pain (CP) is a common and debilitating symptom in patients with knee osteoarthritis (KOA). Massage has been supported as a non-pharmacological intervention for the individual symptom relief of CP. However, relevant evidence of using massage for CP in patients with KOA has been lacking.

METHODS

A systematic search will be performed in the following electronic databases for randomized controlled trials to evaluate the effectiveness and safety of massage for CP of KOA: China National Knowledge Infrastructure (CNKI), Wan Fang, PubMed, EMBASE, PsycINFO, and the Cochrane Library databases from their inception to December 2021. The entire process will include study selection, data extraction, risk of bias assessment and meta-analysis.

RESULTS

This proposed study will evaluate the effectiveness and safety of massage for CP in patients with KOA. Changes in pain relief and adverse effect will be included in our outcomes.

CONCLUSIONS

This systematic review will provide evidence for assessing the credibility of massage for CP in patients with KOA.

DISSEMINATION AND ETHICS

The results of this review will be disseminated through peer-reviewed publication. This review does not require ethical approval because all of the data used in this systematic review and meta-analysis have already been published. Furthermore, all of these data will be analyzed anonymously during the review process.

Higher Incidence of Radiographic Posttraumatic Osteoarthritis With Transtibial Femoral Tunnel Positioning Compared With Anteromedial Femoral Tunnel Positioning During Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Anteromedial (AM) femoral tunnel positioning in anterior cruciate ligament reconstruction (ACLR) has been reported by some authors to yield superior clinical and functional outcomes compared with the transtibial (TT) approach; however, differences in the subsequent rates of posttraumatic osteoarthritis (PTOA) are not clear.

PURPOSE

To perform a systematic review and meta-analysis of the literature to evaluate the influence of femoral tunnel positioning during primary ACLR on the development of radiographic PTOA.

STUDY DESIGN

Systematic review and Meta-analysis.

METHODS

The Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed (1980-2019), and MEDLINE (1980-2019) were queried for all studies describing the development of PTOA after TT or AM ACLR. Data pertaining to patient demographics, ACLR technique, and radiographic PTOA were extracted. A meta-analysis utilizing the DerSimonian-Laird method for random effects was used to compare the weighted proportion of PTOA after ACLR between the TT and AM approaches.

RESULTS

There were 16 studies identified for inclusion with a total of 1546 patients. The mean follow-up across all studies was 10.9 years (range, 5.4-17.8 years). The mean follow-up in the AM and TT groups was 10.8 years (range, 5.4-17 years) and 11.4 years (range, 6-17.8 years), respectively. A total of 783 (50.6%) patients underwent TT ACLR. Of these patients, 401 (weighted mean, 49.3%) developed radiographic PTOA. A total of 763 (49.4%) patients underwent AM ACLR. Of these patients, 166 (mean, 21.8%) went on to develop radiographic PTOA. The meta-analysis demonstrated a significantly greater rate of PTOA after ACLR using a TT technique compared with an AM technique overall (49.3% vs 25.4%, respectively; P < .001) and when studies were stratified by 5- to 10-year (53.7% vs 14.2%, respectively; P < .001) and greater than 10-year (45.6% vs 31.2%, respectively; P < .0001) follow-up.

CONCLUSION

TT ACLR was associated with higher overall rates of radiographic PTOA compared with the AM ACLR approach. The rates of radiographic PTOA after ACLR with a TT approach were also significantly higher than using an AM approach when stratified by length of follow-up (5- to 10-year and >10-year follow-up).

The effects of gluteus medius and tibialis anterior kinesio taping on postural control, knee kinematics, and knee proprioception in female athletes with dynamic knee valgus

OBJECTIVES

This study aimed to investigate the effects of Kinesio taping on postural control, kinematics, and knee proprioception in female athletes with dynamic knee valgus (DKV).

DESIGN

a single-blind randomized clinical trial.

PARTICIPANTS

40 female athletes between the age of 18 and 28 years with DKV in single-leg drop landing (>13°) participated in this study. They were randomly classified into the Kinesio taping (KT) and placebo control (PC) groups.

MAIN OUTCOME MEASURES

All the evaluations and measurements were performed on each subject in the pre-test and post-test stages (with an interval of 72 h). The dynamic balance (Y balance test), proprioception (Knee position sense error), and knee kinematics (flexion and DKV angles) of the subjects were measured, prior and post gluteus medius and tibialis anterior KT.

RESULTS

The results of study demonstrate that the DKV angle and knee position sense error significantly decreased and YBT increased in the KT group from pre-test to post-test (p < 0.05). Nevertheless, there was no significant difference in knee flexion angle (p > 0.05).

CONCLUSION

The results of the present study indicated that KT improves dynamic balance and proprioception and reduces the DKV angle. Therefore, KT is recommended for female athletes with DKV.

A Novel Mutation of the KLK6 Gene in a Family With Knee Osteoarthritis

To investigate the correlation between gene mutation and knee osteoarthritis (KOA), a whole-exome sequencing (WES) was applied to analyze blood samples of four KOA patients and two normal subjects in a family. Gene mutations were identified by gene-trapping and high-throughput sequencing analysis across the differences between the patients and normal subjects. The interactive gene network analysis on the retrieval of interacting genes (STRING) database and the KOA-related genes expression data sets was performed. A possibly detrimental and nonsynonymous mutation at the kallikrein-related peptidase 6 (KLK6) gene (rs201586262, c. C80A, P27H) was identified and attracted our attention. KLK6 belongs to the kallikrein family of serine proteases and its serum level is known as a prevalent biomarker in inflammatory and malignant diseases. KLK6 expresses in the extracellular compartment for matrix degradation, highlighting that KLK6 plays a role in the pathogenesis of KOA. By using the gene databases, the KOA-related genes were mined after de-duplication and IL6 was selected as the most relevant gene through interactive analysis of protein-protein interaction (PPI) network. The data suggested that KLK6 gene mutation and the related expression alteration of IL6 gene might determine the occurrence of hereditary KOA. The is the first study discovering the gene mutation of KLK6 as a factor of pathogenesis of KOA, especially the hereditary KOA.

The Relationship Between Changes in Movement and Activity Limitation or Pain in People With Knee Osteoarthritis: A Systematic Review

OBJECTIVE

To report whether changes in knee joint movement parameters recorded during functional activities relate to change in activity limitation or pain after an exercise intervention in people with knee osteoarthritis (OA).

DESIGN

Etiology systematic review.

LITERATURE SEARCH

Four databases (MEDLINE, Embase, CINAHL, and AMED) were searched up to January 22, 2021.

STUDY SELECTION CRITERIA

Randomized controlled trials or cohort studies of exercise interventions for people with knee OA that assessed change in knee joint movement parameters (moments, kinematics, or muscle activity) and clinical outcomes (activity limitation or pain).

DATA SYNTHESIS

A descriptive synthesis of functional activities, movement parameters, and clinical outcomes.

RESULTS

From 3182 articles, 22 studies met the inclusion criteria, and almost all were of low quality. Gait was the only investigated functional activity. After exercise, gait parameters changed 26% of the time, and clinical outcomes improved 90% of the time. A relationship between group-level changes in gait parameters and clinical outcomes occurred 24.5% of the time. Two studies directly investigated an individual-level relationship, reporting only 1 significant association out of 8 correlations tested.

CONCLUSION

Most studies reported no change in gait-related movement parameters despite improvement in clinical outcomes, challenging the belief that changing movement parameters is always clinically important in people with knee OA. J Orthop Sports Phys Ther 2021;51(10):492-502. doi:10.2519/jospt.2021.10418.

Recent Advances in the Neural Control of Movements: Lessons for Functional Recovery

We review the current views on the control and coordination of movements following the traditions set by Nikolai Bernstein. In particular, we focus on the theory of neural control of effectors - from motor units to individual muscles, to joints, limbs, and to the whole body - with spatial referent coordinates organized into a hierarchy with multiple few-to-many mappings. Further, we discuss synergies ensuring stability of natural human movements within the uncontrolled manifold hypothesis. Synergies are organized within the neural control hierarchy based on the principle of motor abundance. Movement disorders are discussed as consequences of an inability to use the whole range of changes in referent coordinates (as in spasticity) and an inability to ensure controlled stability of salient variables as reflected in indices of multi-element synergies and their adjustments in preparation to actions (as in brain disorders, including Parkinson's disease, multiple-system atrophy, and stroke). At the end of the review, we discuss possible implications of this theoretical approach to peripheral disorders and their rehabilitations using, as an example, osteoarthritis. In particular, "joint stiffening" is viewed as a maladaptive strategy, which can compromise stability of salient variables during walking.

Are there different gait profiles in patients with advanced knee osteoarthritis? A machine learning approach

BACKGROUND

Determine whether knee kinematics features analyzed using machine-learning algorithms can identify different gait profiles in knee OA patients.

METHODS

3D gait kinematic data were recorded from 42 patients (Kellgren-Lawrence stages III and IV) walking barefoot at individual maximal gait speed (0.98 ± 0.34 m/s). Principal component analysis, self-organizing maps, and k-means were applied to the data to identify the most relevant and discriminative knee kinematic features and to identify gait profiles.

FINDINGS

Four different gait profiles were identified and clinically characterized as type 1: gait with the knee in excessive varus and flexion (n = 6, 14%, increased knee adduction and increased maximum and minimum knee flexion, p < 0.01); type 2: gait with knee external rotation, either in varus or valgus (n = 11, 26%, excessive maximum and minimum external rotation, p < 0.001); type 3: gait with a stiff knee (n = 17, 40%, decreased knee flexion range of motion, p < 0.001); and type 4: gait with knee varus 'thrust' and decreased rotation (n = 8, 19%, increased and reduced range of motion in the coronal and transverse plane, respectively, p < 0.05).

INTERPRETATION

In a group of patients with homogeneous Kellgren-Lawrence classification of knee OA, gait kinematics data permitted to identify four different gait profiles. These gait profiles can be a valuable tool for helping surgical decisions and treatment. To allow generalization, further studies should be carried with a larger and heterogeneous population.

Association Between Knee Joint Muscle Activation and Knee Joint Moment Patterns During Walking in Moderate Medial Compartment Knee Osteoarthritis: Implications for Secondary Prevention

OBJECTIVE

To determine associations between knee moment features linked to osteoarthritis (OA) progression, gait muscle activation patterns, and strength.

DESIGN

Cross-sectional secondary analysis.

SETTING

Gait laboratory.

PARTICIPANTS

Convenience sample of 54 patients with moderate, medial knee OA (N=54).

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Knee moments and quadriceps and hamstrings activation were examined during walking. Knee extensor and flexor strength were measured. Waveform patterns were extracted using principal component analysis. Each measured waveform was scored against principal components (PCs) that captured overall magnitude (PC1) and early to midstance difference (PC2) features, with higher PC2 scores interpreted as greater moment differential and more prolonged muscle activity. Correlations were calculated between moment PC scores and muscle PC and strength scores. Regression analyses determined moment PC score variance explained by muscle PC scores and strength.

RESULTS

All correlations for knee adduction moment difference feature (KAMPC2) and prolonged muscle activity (PC2) were significant (r=-0.40 to -0.54). Knee flexion moment difference feature (KFMPC2) was significantly correlated with all quadriceps and medial hamstrings PC2 scores (r=-0.47 to -0.61) and medial hamstrings magnitude feature (PC1) (r=-0.52). KAMPC2 was significantly correlated with knee flexor strength (r=0.43), and KFMPC2 was significantly correlated with knee extensor (r=0.60) and flexor (r=0.55) strength. Regression models including muscle PC2 scores and knee flexor strength explained 46% of KAMPC2 variance, whereas muscle PC2 scores and knee extensor strength explained 59% of KFMPC2 variance.

CONCLUSIONS

Muscle activation patterns and strength explained significant variance in moment difference features, highest for the knee flexion moment. This supports that exercises such as neuromuscular training, focused on appropriate muscle activation patterns, and strengthening have the potential to alter dynamic loading gait patterns associated with knee OA clinical progression.

Towards planning of osteotomy around the knee with quantitative inclusion of the adduction moment: a biomechanical approach

PURPOSE

Despite practised for decades, the planning of osteotomy around the knee, commonly using the Mikulicz-Line, is only empirically based, clinical outcome inconsistent and the target angle still controversial. A better target than the angle of frontal-plane static leg alignment might be the external frontal-plane lever arm (EFL) of the knee adduction moment. Hypothetically assessable from frontal-plane-radiograph skeleton dimensions, it might depend on the leg-alignment angle, the hip-centre-to-hip-centre distance, the femur- and tibia-length.

METHODS

The target EFL to achieve a medial compartment force ratio of 50% during level-walking was identified by relating in-vivo-measurement data of knee-internal loads from nine subjects with instrumented prostheses to the same subjects' EFLs computed from frontal-plane skeleton dimensions. Adduction moments derived from these calculated EFLs were compared to the subjects' adduction moments measured during gait analysis.

RESULTS

Highly significant relationships (0.88 ≤ R2 ≤ 0.90) were found for both the peak adduction moment measured during gait analysis and the medial compartment force ratio measured in vivo to EFL calculated from frontal-plane skeleton dimensions. Both correlations exceed the respective correlations with the leg alignment angle, EFL even predicts the adduction moment's first peak. The guideline EFL for planning osteotomy was identified to 0.349 times the epicondyle distance, hence deducing formulas for individualized target angles and Mikulicz-Line positions based on full-leg radiograph skeleton dimensions. Applied to realistic skeleton geometries, widespread results explain the inconsistency regarding correction recommendations, whereas results for average geometries exactly meet the most-consented "Fujisawa-Point".

CONCLUSION

Osteotomy outcome might be improved by planning re-alignment based on the provided formulas exploiting full-leg-radiograph skeleton dimensions.

Therapeutic effect of Qinglong tail-wagging acupuncture method in knee osteoarthritis and its influence on inflammatory factors

OBJECTIVES

This study explored and analyzed the healing effect of Qinglong tail-wagging acupuncture method in therapy of knee osteoarthritis and its influence on inflammatory factors.

METHODS

93 elderly patients with acute onset of knee osteoarthritis that hospitalized from March 2017 to June 2019 were admitted and randomly separated into observation group (n=48) and control group (n=45) in line with the method of random data form. The control group was given conventional electro-acupuncture, and the observation group was treated with the qinglong tail-waving acupuncture method. The clinical efficacy, pre- and post-VAS score, Lequesne and WOMAC indexes, and changes in serum inflammatory factor levels pre-and-post treatment were compared between the two sets of subjects.

RESULTS

The overall response rate of clinical treatment in observation group was remarkably higher than that of the control group (P < 0.05). Besides, the VAS, Lequesne as well as WOMAC scores of two groups after treatment were significantly reduced than those in pre-treatment (P < 0.05), and the indexes in observation group were remarkably lower than those in control group (P < 0.05). In addition, the serum IL-6, NO and TNF-α concentration of the two sets of subjects in post-treatment reduced significantly than that in pre-treatment (P < 0.05), and the serum IL-6, NO and TNF-α concentration in observation group were remarkably decreased than those in control group (P < 0.05).

CONCLUSION

The acupuncture method of Qinglong tail-wagging has good healing effect on remedy of elderly knee osteoarthritis. The curative method is able to improve the patients' function of knee joint and reduce the concentration of serum inflammatory factor in patients with knew osteoarthritis.

Joint hypermobility and its association with self-reported knee health: A cross-sectional study of healthy Australian adults

AIM

The primary aim of this study was to determine the association between generalized joint hypermobility (GJH), knee-specific hypermobility (KSH) and self-reported knee health in an Australian population. Secondary aims included elucidating ethnic/gender differences in GJH/KSH prevalence and knee health, and identifying KSH using a novel knee extension range of motion cut-off method.

METHOD

Knee extension range, Beighton score, and 5 domains of the Knee Injury and Osteoarthritis Outcome Score (KOOS) were collected from adults aged 18-101 years self-identifying as healthy, and were grouped by ethnicity and gender. Two established Beighton score criteria and 1 novel knee extension range cut-off method were used to determine GJH and KSH respectively. Point-biserial correlation tested the associations between GJH/KSH and KOOS. Differences in GJH/KSH prevalence and knee health between ethnic/gender groups were determined with the Chi-squared test.

RESULTS

Of 732 participants (50% male), 80.3% were Caucasian. No correlations were found between GJH and KOOS while a very weak correlation was found between KSH and 1 KOOS domain (r > -.30; P = .04). Prevalence of GJH was higher in non-Caucasians (17.4% vs 5.6%, P < .001) and females (4.4% vs 1.1%, P = .007). Prevalence of KSH between ethnic and gender groups was not significantly different (P = .50 and P = .69 respectively). Non-Caucasians scored higher (better) in all KOOS domains than Caucasians (all P < .05).

CONCLUSION

Those who met the age- and gender-specific criteria for GJH/KSH did not report worse knee health than their non-hypermobile counterparts. Clinicians can assure individuals who exhibit GJH/KSH that these are not associated with lower knee health and function.

The synergistic effects of applying low-level laser therapy plus ultrasound on pain and muscle function in patients with knee osteoarthritis: A protocol of a randomized double-blind study

BACKGROUND

To our knowledge, only 1 study with limited sample size tried to evaluate the synergistic effects of ultrasound and low-level laser therapy (LLLT) in patients with knee osteoarthritis. Further research is needed to confirm this synergy with larger numbers and better design. Therefore, we will conduct this present randomized double-blind study to evaluate the synergistic effects of simultaneously applying ultrasound plus LLLT on pain and muscle function in patients with knee osteoarthritis.

METHODS

The study protocol is a randomized, controlled, double-blind design. The study will be conducted at our academic hospital from February 2021 to January 2022. The study protocol was approved through Institutional Review Board in the Hunan Provincial People's Hospital. Patients will be assigned at random to the ultrasound + LLLT group, LLLT group, or the ultrasound group. After baseline examination, all patients will be given a full explanation of the treatment protocol and will be required to sign a written informed consent for study participation and for publication of the results. All the data collectors, surgeons, statistical analysts, as well as result assessors are not aware of grouping assignment. The primary outcome is weekly change in pain intensity relative to baseline through 6 weeks of therapy.

RESULTS

This protocol will provide a reliable theoretical basis for the following research.

CONCLUSION

It is assumed that there will be a remarkable difference in postoperative outcomes between the intervention and control groups.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry6470).

A comparison of the effects of Chinese non-pharmaceutical therapies for pain control in knee osteoarthritis: A protocol for a systematic review and network meta-analysis

BACKGROUND

Knee osteoarthritis (KOA) is a chronic degenerative joint disease, leading to pain and functional limitation in the elderly. The non-pharmaceutical therapy is recommended firstly by different guidelines for KOA management strategies. In China, there are various forms of non-pharmaceutical treatments for KOA, which are considered beneficial in relieving KOA pain. However, there is no consensus on which is the optimal non-pharmaceutical regimens. Thus, present network meta-analysis aims to assess the comparative efficacy of available Chinese non-pharmaceutical therapies, especially in pain management.

METHODS

PubMed, EMBASE, Cochrane library, Web of Science, China national knowledge infrastructure, VIP, Wan Fang will be systematically searched their inception to April 2020. Randomized controlled trials that compared the effect of non-pharmaceutical therapies on pain control in KOA will be included, including traditional acupuncture, electroacupuncture, warming needle, fired needle, acupuncture followed by moxibustion, moxibustion and massage. The primary outcome was the knee pain levels, and secondary outcome was the comprehensive indicators. Risk of bias assessment of the included studies will be performed according to the Cochrane risk of bias tool. The pairwise and network meta-analysis will be performed by STATA 14.0 and GeMTC softwares.

RESULTS

This study is ongoing and will be submitted to a peer-reviewed journal for publication.

CONCLUSION

This study will provide a comprehensive evidence on the effects of Chinese non-pharmaceutical therapies for pain control in KOA.

PROSPERO REGISTRATION NUMBER

CRD42018106575.

A randomized study protocol comparing the platelet-rich plasma with hyaluronic acid in the treatment of symptomatic knee osteoarthritis

BACKGROUND

In recent years, intra articular injection of platelet rich plasma has attracted increasing attention. The major aim of our current randomized controlled double-blind study was to compare long-term outcomes of intra-articular injection of hyaluronic acid or platelet rich plasma in the treatment of the patients with knee osteoarthritis.

METHODS

This is a kind of double-blind, randomized, prospective, and comparative clinical investigation with the allocation ratio of 1:1 and was approved by our institutional review Committee. Between 2020 and 2021, altogether 2 hundred patients will be selected to participate in our present study. We will report the randomized experiments in accordance with the guidelines of Consolidated Standards of Reporting Trials and then offer the Consolidated Standards of Reporting Trials flow chart. The inclusion criteria were: patients aged from 40 to 70 years old, patients with chief complaint history of at least 1 month and knee joint pain for nearly 6 months, need the analgesic drug treatment, and radiology confirmed knee osteoarthritis. The eligible patients would be randomly divided into 2 groups through applying the random numbers generated by computer before surgery. Outcomes after treatment were assessed using the Western Ontario and McMaster University and the scoring systems of visual analogue scale which were recorded through questionnaires accomplished via the patients prior to the first injection and then at three and six months, 1 and 2 years follow-up. Any adverse events occurred within 1 year after surgery were recorded during follow-up.

RESULTS

This should suggest whether biological methods can offer more lasting outcomes than the viscosification.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry6265).

Unicompartmental knee replacement and high tibial osteotomy for medial unicompartmental knee osteoarthritis: A comparative study protocol

BACKGROUND

Many clinical studies have been published in the literature to compare the outcomes of unicompartmental knee replacement (UKR) and high tibial osteotomy (HTO), but reached different conclusions. Therefore, the relative merits and demerits of these 2 procedures remain under debate. The purpose of the present protocol was to design a retrospective comparative study to further investigate the clinical effectiveness of HTO compared to UKR in the medial unicompartmental osteoarthritis of knee patients.

METHODS

This is an observational retrospective research, which prospectively collected the data from several surgeons in our center and utilized the above 2 methods to treat the unicompartmental osteoarthritis of knee. In our single hospital, we reviewed unicompartmental knee osteoarthritis patients treated using UKR or HTO from June 2016 to February 2018. For the HTO, its criteria included:For the UKR, its inclusion criteria containedIn our cohorts, the clinical investigations of the knee were composed of the objective parameters, which were recorded and then documented through utilizing the Function Score and Orthopedic American Knee Society Knee Score. The extra clinical findings evaluated involved operative time, postoperative requirements of blood transfusion, possible postoperative complications, as well as the range of motion.

CONCLUSION AND DISCUSSION

The results of this study will provide clinical evidence on appropriate surgical treatment for patients with medial unicompartmental knee osteoarthritis.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry6152).

Knee kinematics of severe medial knee osteoarthritis showed tibial posterior translation and external rotation: a cross-sectional study

BACKGROUND

Knee osteoarthritis (OA) gradually reduces knee function and limits activities of daily living with age. However, the progression of abnormal kinematics of the knee in knee OA is unclear.

AIMS

This study aimed to clarify the relationship between stage of knee OA and abnormal knee kinematics and to identify a strategy for prevention of knee OA.

METHODS

A total of 112 knees of 99 patients (45 men/54 women; 55.9 ± 18.2 years), comprising 28 (27/1) in Kellgren-Lawrence grade 0, 18 (8/10) in grade 1, 27 (2/25) in grade 2, 28 (6/22) in grade 3, and 11 (3/8) in grade 4, were enrolled in this cross-sectional study. In vivo knee kinematics was obtained using a three-dimensional-to-two-dimensional registration technique utilizing CT-based bone models and lateral fluoroscopy during knee extension-flexion in an upright sitting position and squatting.

RESULTS

The external rotation angle of the tibia relative to the femur was greater in grade 3/4 knees than in grade 0/1 knees and tibial posterior translation was greater in grade 3/4 knees than in grade 0-2 knees.

DISCUSSION

Age-related changes in muscle activity and joint instability are considered to be the cause of these abnormal kinematics.

CONCLUSIONS

As the stage of knee OA progresses, there was a tendency toward increasing tibial external rotation and tibial posterior translation during knee extension-flexion in sitting position and squatting. Prevention of the progress of the abnormal knee kinematics may prevent the progression of the knee OA.

Trochleoplasty improves knee flexion angles and quadriceps function during gait only if performed bilaterally

PURPOSE

To investigate if a trochleoplasty increases knee flexion angles and extensor moments in the gait of patients with patellar instability and to compare postoperative gait to a healthy control group.

METHODS

A bilateral dislocation group (6 patients) and a unilateral dislocation group (14 patients) were treated with bilateral and unilateral trochleoplasty, respectively. Kinematics and kinetics of the lower extremity were captured using 3D-gait analysis (VICON, 12 cameras, 200 Hz, plug-in-gait, two force plates). The mean of six trials was computed. The gait cycles were compared pre to postoperatively for each group. The gait of the two groups was compared to each other and the gait of a healthy population (54 knees).

RESULTS

After trochleoplasty, the knee flexion angles and knee extensor moments only increased in the bilateral dislocation group, whereas the gait pattern of the unilateral dislocation group remained unchanged. Compared to the healthy population, the postoperative gait pattern of the bilateral dislocation group did not differ. In contrast, knee flexion angles and extensor moments of the unilateral dislocation group were still lower.

CONCLUSION

In adolescents with bilateral recurrent patellar dislocations, trochleoplasty of both knees increases knee flexion angles and knee extensor moments comparable to normal gait. Unilateral symptomatic patients undergoing a unilateral trochleoplasty did not achieve normal walking. These findings point out that patellar instability should be considered as a bilateral problem, even in patients with unilateral dislocations.

LEVEL OF EVIDENCE

III.

Relative difference in muscle strength between patients with knee osteoarthritis and healthy controls when tested bilaterally and joint-inclusive: an exploratory cross-sectional study

Background

To improve the goal-directedness of strength exercises for patients with knee osteoarthritis (KOA), physical rehabilitation specialists need to know which muscle-groups are most substantially weakened across the kinetic chain of both lower extremities. The purpose was to improve the knowledge base for strength exercise therapy. The objective was to explore the relative differences in muscle strength in the main directions bilaterally across the hip, knee, and ankle joints between patients with light-to-moderate symptomatic and radiographic KOA and people without knee complaints.

Methods

The design was an exploratory, patient vs. healthy control, and cross-sectional study in primary/secondary care. Twenty-eight patients with mild to moderate KOA (18 females, mean age 61) and 31 matched healthy participants (16 females, mean age 55), participated. Peak strength was tested concentrically or isometrically in all main directions for the hip, knee, and ankle joints bilaterally, and compared between groups. Strength was measured by a Biodex Dynamometer or a Commander II Muscle Tester (Hand-Held Dynamometer). Effect sizes (ES) as Cohen’s d were applied to scale and rank the difference in strength measures between the groups. Adjustment for age was performed by analysis of covariance.

Results

The most substantial muscle weaknesses were found for ankle eversion and hip external and internal rotation in the involved leg in the KOA-group compared to the control-group (ES [95% CI] −0.73 [−1.26,-0.20], − 0.74 [−1.26,-0.21], −0.71 [−1.24,-0.19], respectively; p < 0.01). Additionally, smaller but still significant moderate muscle weaknesses were indicated in four joint–strength directions: the involved leg’s ankle inversion, ankle plantar flexion, and knee extension, as well as the uninvolved leg’s ankle dorsal flexion (p < 0.05). There was no significant difference for 17 of 24 tests.

Conclusions

For patients with KOA between 45 and 70 years old, these explorative findings indicate the most substantial weaknesses of the involved leg to be in ankle and hip muscles with main actions in the frontal and transverse plane in the kinetic chain of importance during gait. Slightly less substantial, they also indicate important weakness of the knee extensor muscles. Confirmatory studies are needed to further validate these exploratory findings.

Effects of treadmill running and limb immobilization on knee cartilage degeneration and locomotor joint kinematics in rats following knee meniscal transection

OBJECTIVE

This study examined the effects of reduced and elevated weight bearing on post-traumatic osteoarthritis (PTOA) development, locomotor joint kinematics, and degree of voluntary activity in rats following medial meniscal transection (MMT).

DESIGN

Twenty-one adult rats were subjected to MMT surgery of the left hindlimb and then assigned to one of three groups: (1) regular (i.e., no intervention), (2) hindlimb immobilization, or (3) treadmill running. Sham surgery was performed in four additional rats. Voluntary wheel run time/distance was measured, and 3D hindlimb kinematics were quantified during treadmill locomotion using biplanar radiography. Rats were euthanized 8 weeks after MMT or sham surgery, and the microstructure of the tibial cartilage and subchondral bone was quantified using contrast enhanced micro-CT.

RESULTS

All three MMT groups showed signs of PTOA (full-thickness lesions and/or increased cartilage volume) compared to the sham group, however the regular and treadmill-running groups had greater osteophyte formation than the immobilization group. For the immobilization group, increased volume was only observed in the anterior region of the cartilage. The treadmill-running group demonstrated a greater knee varus angle at mid-stance than the sham group, while the immobilization group demonstrated greater reduction in voluntary running than all the other groups at 2 weeks post-surgery.

CONCLUSIONS

Elevated weight-bearing via treadmill running at a slow/moderate speed did not accelerate PTOA in MMT rats when compared to regular weight-bearing. Reduced weight-bearing via immobilization may attenuate overall PTOA but still resulted in regional cartilage degeneration. Overall, there were minimal differences in hindlimb kinematics and voluntary running between MMT and sham rats.

Relative difference among 27 functional measures in patients with knee osteoarthritis: an exploratory cross-sectional case-control study

Background

To raise the effectiveness of interventions, clinicians should evaluate important biopsychosocial aspects of the patient’s situation. There is limited knowledge of which factors according to the International Classification of Function, Disability, and Health (ICF) are most deviant between patients with knee osteoarthritis (KOA) and healthy individuals. To assist in measures’ selection, we aimed to quantify the differences between patients with KOA and healthy controls on various measures across the ICF dimensions of body function, activity, and participation.

Methods

We performed an exploratory cross-sectional case-control study. In total, 28 patients with mild-to-moderate KOA (mean age 61 years, 64% women) referred by general physicians to a hospital’s osteoarthritis-school, and 31 healthy participants (mean age 55 years, 52% women), volunteered. We compared between-group differences on 27 physical and self-reported measures derived from treatment guidelines, trial recommendations, and trial/outcome reviews. Independent t-test, Chi-square, and Mann-Whitney U test evaluated the significance for continuous parametric, dichotomous, and ordinal data, respectively. For parametric data, effect sizes were calculated as Cohen’s d. For non-parametric data, ds were estimated by p-values and sample sizes according to statistical formulas. Finally, all ds were ranked and interpreted after Hopkins’ scale. An age-adjusted sensitivity-analysis on parametric data validated those conclusions.

Results

Very large differences between patients and controls were found on the Pain numeric rating scale¹, the Knee Injury and Osteoarthritis Scale (KOOS, all subscales)², as well as the Örebro Musculoskeletal psychosocial scale³ (P < 0.0001). Large differences were found on the Timed 10-steps-up-and-down stair climb test⁴ and Accelerometer registered vigorous-intensity physical activity in daily life⁵ (P < 0.001). Respectively, these measures clustered on ICF as follows: ¹body function, ²all three ICF-dimensions, ³body function and participation, ⁴activity, and ⁵participation.

Limitations

The limited sample excluded elderly patients with severe obesity.

Conclusions

Very large differences across all ICF dimensions were indicated for the KOOS and Örebro questionnaires together for patients aged 45–70 with KOA. Clinicians are suggested to use them as means of selecting supplementary measures with appropriate discriminative characteristics and clear links to effective therapy. Confirmative studies are needed to further validate these explorative and partly age-unadjusted conclusions.

Paradoxical relationship in sensorimotor system: Knee joint position sense absolute error and joint stiffness measures

BACKGROUND

Relationships between joint position sense and the sensorimotor characteristics such as joint stiffness, time to detect motion, and time to peak torque during a perturbation test have rarely been investigated due to methodological challenges. The purpose of this study was to compare joint position sense and the sensorimotor characteristics in healthy individuals.

METHODS

A total of 26 subjects were recruited and completed joint position sense and a perturbation test on isokinetic dynamometer. Joint position sense was assessed by comparison of the absolute angle difference between a reference and replicated position. During the perturbation test, the dynamometer moved the knee flexion angle from 70° to 30° (0° represents a full knee extension) at the velocity of 500° per second at random. Subjects were asked to react and pull back the leg as soon as they perceived the movement. Pearson or Spearman's correlation coefficients were used to assess these relationships (P < 0.05).

FINDINGS

Larger joint position sense absolute error values were significantly correlated with higher short-range at 50 milliseconds (r = 0.572, P = 0.002), at 100 milliseconds (ρ = 0.416, P = 0.035), and reactive joint stiffness (r = 0.395, P = 0.046).

INTERPRETATION

There was a paradoxical relationship between higher joint stiffness and worsened joint position sense. Potential reasons include sensory weighting within the sensorimotor system and thixotropic properties (after-effects of muscle eccentric contractions to increase stiffness and alter joint position sense).