Associations of knee extensor strength and standing balance with physical function in knee osteoarthritis

Cost and outcomes of Hospital-based Usual cAre versus Tele-monitor self-directed Rehabilitation (HUATR) in patients with total knee arthroplasty: A randomized, controlled, non-inferiority trial

OBJECTIVE

To evaluate the clinical efficacy and cost-effectiveness of telemonitored self-directed rehabilitation (TR) compared with hospital-based rehabilitation (HBR) for patients with total knee arthroplasty (TKA).

DESIGN

In this randomized, non-inferiority clinical trial, 114 patients with primary TKA who were able to walk independently preoperatively were randomized to receive HBR (n = 58) or TR (n = 56). HBR comprised at least five physical therapy sessions over 10 weeks. TR comprised a therapist-led onboarding session, followed by a 10-week unsupervised home-based exercise program, with asynchronous monitoring of rehabilitation outcomes using a telemonitoring system. The primary outcome was fast-paced gait speed at 12 weeks, with a non-inferiority margin of 0.10 m/s. For economic analysis, quality-adjusted-life-years (QALY) was the primary economic outcome (non-inferiority margin, 0.027 points).

RESULTS

In Bayesian analyses, TR had >95% posterior probability of being non-inferior to HBR in gait speed (week-12 adjusted TR-HBR difference, 0.02 m/s; 95%CrI, -0.05 to 0.10 m/s; week-24 difference, 0.01 m/s; 95%CrI, -0.07 to 0.10 m/s) and QALY (0.006 points; 95%CrI, -0.006 to 0.018 points). When evaluated from a societal perspective, TR was associated with lower mean intervention cost (adjusted TR-HBR difference, -S$227; 95%CrI, -112 to -330) after 24 weeks, with 82% probability of being cost-effective compared with HBR at a willingness to pay of S$0/unit of effect for the QALYs.

CONCLUSIONS

In patients with uncomplicated TKAs and relatively good preoperative physical function, home-based, self-directed TR was non-inferior to and more cost-effective than HBR over a 24-week follow-up period. TR should be considered for this patient subgroup.

Predictors of static and dynamic balance control in kidney transplant recipients

BACKGROUND

We aimed to evaluate balance control and lower extremity muscle strength in kidney transplant recipients (KTRs) including a comparison to a healthy control group and determine the predictors of static and dynamic balance control after kidney transplantation.

METHODS

In this study 40 KTRs and 40 healthy controls were included. Balance control was assessed using the Biodex balance system. The static postural stability test (SPST) and clinical test of sensory integration and balance (CTSIB) were used to assess static balance control whereas the dynamic postural stability test (DPST) and limits of stability test (LOST) were used for dynamic balance control. Lower extremity muscle strength was measured with a hand-held dynamometer. Renal functions and laboratory findings of KTRs were recorded.

RESULTS

All the stability index scores of SPST and sway index in CTSIB were significantly higher in KTRs compared to healthy controls. The right anteroposterior stability index score in DPST and the reaction time in LOST were significantly higher whereas overall score in LOST and lower extremity muscle strength were significantly lower in KTRs. The linear regression analysis revealed that hemoglobin was the predictor of static balance control accounting for 11% of the variance and body weight was the predictor of dynamic balance control accounting for 34% of the variance.

CONCLUSION

Balance control, both static and dynamic, are impaired in KTRs as well as lower extremity muscle strength. Hemoglobin level is a predictor of static balance control whereas body weight is a predictor of dynamic balance control after kidney transplantation.

Asymmetries and relationships between muscle strength, proprioception, biomechanics, and postural stability in patients with unilateral knee osteoarthritis

Background: The pathological mechanism of knee osteoarthritis (KOA) is unknown. KOA degeneration may be associated with changes in muscle strength, proprioception, biomechanics, and postural stability.

Objective: This study aimed to assess asymmetries in muscle strength, proprioception, biomechanics, and postural stability of bilateral lower limbs in patients with unilateral KOA and healthy controls and analyze correlations between KOA and these parameters.

Methods: A total of 50 patients with unilateral KOA (age range: 50-70) and 50 healthy subjects were recruited as study participants (age range: 50-70). Muscle strength, proprioception, femorotibial angle (FTA), femoral condylar–tibial plateau angle (FCTP), average trajectory error (ATE), and center of pressure (COP) sways areas were accessed in study participants, and the correlation between these variables was investigated.

Results: In patients with unilateral KOA, lower limb muscle strength was significantly lower on the symptomatic side than on the asymptomatic side (p < 0.01), while the proprioception (degree error), FTA, FCTP, and ATE were substantially higher compared to the asymptomatic side (p < 0.01). However, no significant difference was observed in the healthy controls (p > 0.05). Patients with unilateral KOA had lower muscle strength than healthy controls (p < 0.05), but their proprioception (degree error: the difference between the target and reproduction angles), ATE, and COP sway areas were higher (p < 0.05). Muscle strength was found to be negatively correlated with ATE and COP sways areas (p < 0.05), whereas proprioception (degree error) was positively correlated with ATE and COP sways areas (p < 0.05) in all study participants. However, no correlation was found between FTA, FCTP, and ATE, COP sways areas in patients with unilateral KOA (p > 0.05).

Conclusion: In patients with unilateral KOA, muscle strength, proprioception, biomechanics, and postural stability of bilateral limbs are asymmetrical in unilateral KOA patients. Muscle strength, proprioception, and postural stability are significantly associated variables, and changes in these variables should be considered in KOA prevention and rehabilitation.

Balance factors affecting the quality of life in patients with knee osteoarthritis

Background

Knee osteoarthritis (OA) affects the quality of life (QOL) and balance control of elderly people; our study explored the balance factors that affected the QOL in patients with knee OA.

Objectives

To determine the balance factors that affected the QOL of patients with knee OA who attended general clinics.

Method

A total of 30 healthy controls and 60 patients with mild-to-moderate bilateral knee OA, all aged 55–75 years, were enrolled in our cross-sectional study. All participants were interviewed; the Medical Outcomes Study 36-Item Short-Form Health Survey was used to assess their QOL in eight dimensions, and the Balance Master System was used to evaluate their balance control according to six parameters. Descriptive statistics were used to reduce the data; an independent t-test determined differences between the two groups, and a multiple regression analysis was undertaken to establish associations between variables from the balance control test and SH36 physical and mental health components. The level of statistical significance was set at 5%.

Results

In the OA group, significant negative correlations were observed between sway velocity and the physical health component (p = 0.003) and between sway velocity and the mental health component (p = 0.006). Thus, sway velocity had a major impact on the QOL of patients with knee OA.

Conclusions

The sway velocity at the centre of gravity in balance control was a crucial factor for determining the QOL of patients with bilateral knee OA.

Clinical implications

Sway velocity is a key factor affecting the QOL and may provide a basis to formulate preventive actions and design treatment goals for patients with knee OA.

Beneficial Effects and Potential Mechanisms of Tai Chi on Lower Limb Osteoarthritis: A Biopsychosocial Perspective

Lower limb osteoarthritis (OA) is a chronic, multifactorial disease characterized by impaired physical function, chronic pain, compromised psychological health and decreased social functioning. Chronic inflammation plays a critical role in the pathophysiology of OA. Tai Chi is a type of classical mind-body exercise derived from ancient Chinese martial arts. Evidence supports that Tai Chi has significant benefits for relieving lower limb OA symptoms. Using a biopsychosocial framework, this review aims to elucidate the beneficial effects of Tai Chi in lower limb OA and disentangle its potential mechanisms from the perspective of biology, psychology, and social factors. Complex biomechanical, biochemical, neurological, psychological, and social mechanisms, including strengthening of muscles, proprioception improvement, joint mechanical stress reduction, change of brain activation and sensitization, attenuation of inflammation, emotion modulation and social support, are discussed.

The effect of self-reported knee instability on plantar pressure and postural sways in women with knee osteoarthritis

BACKGROUND

Giving way and knee instability are common problems in patients with knee osteoarthritis, disrupting the daily activities and balance of the affected individual. The present study aimed to evaluate the postural control status of women with knee osteoarthritis with and without self-report knee instability (KI).

METHODS

This cross-sectional, single-blind study was conducted on 57 female patients with knee osteoarthritis. The patients were selected based on the inclusion and exclusion criteria and divided into two groups of with KI (n = 26) and without KI (n = 31). Fear of movement was assessed using the Tampa questionnaire, the degree of knee instability was measured based on the Fitzgard scale, the static and dynamic balance of the subjects were evaluated with open and closed eyes using a Biodex balance device, and foot pressure distribution situation was measured using a FDM-S-Zebris device.

RESULTS

Mean comparison showed a significant difference between the subjects with and without KI in static balance only in anterior-posterior direction with open eyes (p = 0.01) and closed eyes (p = 0.0001). In the dynamic balance test, the subjects in both groups had significant differences in terms of all the indicators of anterior-posterior stability (p = 0.001), medial-lateral stability (p = 0.0001), and overall stability (p = 0.0001) with closed eyes. However, no significant difference was observed with open eyes (p > 0.05). Multiple regression also indicated significant positive correlations between pain intensity and disease duration with the degree of KI (p < 0.05).

CONCLUSIONS

According to the results, there were significant differences between the mean pain scores, static and dynamic balance, and the rate of fall between the women with knee osteoarthritis with and without the KI index. Therefore, patients with knee osteoarthritis, which also has an index of KI, are more susceptible to falls, and proper strategies are required to reduce the level of KI in these patients.

Patellar tendinopathy impairs postural control in athletes: A case-control study

OBJECTIVE

To compare postural control performance between athletes with and without patellar tendinopathy (PT).

DESIGN

Case-control study.

PARTICIPANTS

Fifty-eight athletes, 29 with PT (PT group: PTG) and 29 healthy ones (control group: CG).

MAIN OUTCOME MEASURES

Static and dynamic postural control were assessed with a force platform and the Y-Balance Test (Y-BT), respectively. Quadriceps strength of both limbs was evaluated using an isometric dynamometer.

RESULTS

The PTG exhibited significantly (p < 0.05) higher centre of pressure (CoP) values than the CG on the foam surface, and significantly lower (p < 0.001) anterior, posteromedial and posterolateral normalized reach distances, and composite score in dynamic postural control on the injured limb (IL) compared to non-injured limb (NIL) and dominant limb (DL) of the CG. The quadriceps muscle strength was significantly lower on the IL compared to the NIL (p < 0.01) and DL (p < 0.05) of the CG.

CONCLUSION

Athletes suffering from PT exhibited worse static and dynamic postural control compared to healthy peers. As players with PT frequently continue training despite their tendon pain, physiotherapists and clinicians should incorporate balance rehabilitation programs in the treatment of these players, not only to prevent further potential injuries but also to enhance sport performance.

Dynamic postural control correlates with activities of daily living and quality of life in patients with knee osteoarthritis

Background

Knee osteoarthritis (OA) negatively affects dynamic postural control, which is a basic function that individuals use to perform activities of daily living (ADL). The purpose of this study was to investigate the associations of center of pressure (COP) control during the transition from double-leg to single-leg standing with subjective assessments of ADL and quality of life (QOL) in patients with knee OA.

Methods

Thirty-six patients (29 females) with moderate-to-severe knee OA participated. Dynamic postural control was evaluated during the transition from double-leg to single-leg standing. Each patient stood on a force plate, lifted the less affected limb as fast as possible, and maintained single-leg standing with the more affected limb. The COP movements corresponding to anticipatory postural adjustment (APA) and transitional phases were assessed. The maximum displacement and peak velocity of the COP movements in the medial–lateral direction were calculated. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was used for the subjective assessment of ADL and QOL. Pearson’s product correlation analysis was performed to investigate the associations of COP movements in the APA and transitional phases with KOOS-ADL and KOOS-QOL.

Results

In the APA phase, the maximum COP displacement was significantly correlated with KOOS-ADL (r = -0.353, P = 0.035) and KOOS-QOL (r = -0.379, P = 0.023). In the transitional phase, the maximum COP displacement and peak COP velocity were significantly correlated with KOOS-ADL (maximum displacement: r = 0.352, P = 0.035; peak velocity: r = 0.438, P = 0.008) and with KOOS-QOL (maximum displacement: r = 0.357, P = 0.032; peak velocity: r = 0.343, P = 0.040).

Conclusions

The present study showed that smaller COP movements in the APA phase and smaller and slower COP movements in the transitional phase correlated with poorer ADL and QOL conditions in patients with knee OA. These findings suggest that poor dynamic postural control is associated with poor ADL and QOL conditions in patients with moderate-to-severe medial knee OA. Conservative treatment for patients with knee OA may need to focus on dynamic postural control during the transition from double-leg to single-leg standing.

Gait Velocity and Joint Power Generation After Stroke: Contribution of Strength and Balance

OBJECTIVE

The aim of the study was to assess the degree to which isometric strength of multiple lower limb muscle groups and balance is associated with gait velocity and joint power generation during gait after stroke.

DESIGN

Sixty-three participants in a multisite, multinational, cross-sectional, observational study underwent assessment of gait velocity (10-m walk test), standing balance (computerized posturography), and isometric strength (hand-held dynamometry). Twenty-seven participants had joint power generation assessed (three-dimensional gait analysis). Bivariate associations were examined using Spearman's correlations. Regression models with partial F tests were used to compare the contribution to gait between measures.

RESULTS

Although all muscle groups demonstrated significant associations with gait velocity (ρ = 0.40-0.72), partial F tests identified that ankle plantar flexor and hip flexor strength made the largest contribution to gait velocity. Ankle plantar flexor strength also had strong associations with habitual and fast-paced ankle power generation (ρ = 0.65 and 0.75). Balance had significant associations with habitual and fast gait velocity (ρ = -0.57 and -0.53), with partial F tests showing that the contribution was independent of strength.

CONCLUSIONS

Ankle plantar flexor and hip flexor strength had the largest contribution to gait velocity. Future research may wish to refocus strength assessment and treatment to target the ankle plantar flexors and hip flexors.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: (1) Differentiate the contribution that lower limb strength of each muscle group has on gait velocity after stroke; (2) Appraise the relationship between isometric strength and joint power generation during gait; and (3) Interpret the contribution of both strength and balance to gait after stroke.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s). Physicians should only claim credit commensurate with the extent of their participation in the activity.

Effects of isokinetic muscle strengthening on balance, proprioception, and physical function in bilateral knee osteoarthritis patients with moderate fall risk

OBJECTIVES

This study aims to assess the effects of isokinetic quadriceps and hamstring strengthening exercises on balance, proprioception, and physical function in patients with moderate-to-severe knee osteoarthritis and moderate fall risk.

PATIENTS AND METHODS

Between November 2011 and December 2012, a total of 39 participants (30 females, 9 males; mean age 61.7±8.6 years; range, 18 to 79 years) with Grade 2 or 3 knee osteoarthritis according to the Kellgren-Lawrence radiographic grading system and moderate risk of fall with active knee pain were included in this study. All participants received isokinetic quadriceps and hamstring strengthening exercises for six weeks. Pre-treatment quadriceps and hamstring muscle strength (peak torque and total work value) and quadriceps to hamstring muscle strength ratio at angular velocities of 60°/sec and 180°/sec, range of motion (ROM), average proprioceptive errors at 15-45° and 30-60°, the Berg Balance Scale (BBS) scores, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscale scores, the Visual Analog Scale (VAS) scores, and physical function tests results were compared with the post-treatment results. The correlations of pre- and post-treatment BBS and average proprioceptive error at 15-45° and 30-60° changes to other pre- and post-treatment clinical measurements changes were calculated.

RESULTS

Post-treatment quadriceps and hamstring muscle strength at angular velocities of 60°/sec and 180°/sec and quadriceps to hamstring muscle strength ratios at angular velocity of 60°/sec, ROM, average proprioceptive errors at 15-45° and 30-60°, BBS scores, WOMAC subscale scores, VAS scores, and physical function tests significantly improved compared to the pre-treatment results (p<0.001). Statistically significant correlations were found between the pre- and post-treatment BBS score changes and pre- and post-treatment VAS (p=0.015), WOMAC-Pain (p=0.017), WOMAC-Physical Function (p=0.005) scores and Timed Up and Go Test (p=0.036) scores.

CONCLUSION

Inclusion of isokinetic quadriceps and hamstring strengthening exercises into the rehabilitation programs for the patients with knee osteoarthritis may improve the quality of life and contribute to the decreased risk of fall.

The effects of pain on quadriceps strength, joint proprioception and dynamic balance among women aged 65 to 75 years with knee osteoarthritis

Background

Patients with knee osteoarthritis (OA) were reported to have quadriceps weakness, and impaired proprioception, both related to pain and swelling. It is unclear whether pain alone a causal factor to above findings over the knee joint. The purpose of this study was to assess the effects of knee pain alone on the quadriceps strength, proprioception and dynamic balance in subjects with bilateral knee OA without joint swelling.

Methods

Fourty females with mean age of 68.3 years were involved in this cross-sectional study. The inclusion criteria were bilateral knee OA without joint swelling, with a visual analogue pain scale difference (> 1) between each knee. Patients all underwent assessment of the isokinetic strength of knee muscles, knee proprioceptive acuity, and dynamic balance.

Results

Patients’ more painful knee had weaker isokinetic quadriceps strength than less painful knee at both 60 °/s and 180 °/s (p = 0.01, p = 0.01, respectively). There were no differences in proprioceptive acuity between both knees in all three knee positions. Meanwhile, there was a significant difference in the dynamic balance index measurement between both knees (more painful versus less painful: 3.88 ± 1.15 vs. 3.30 ± 1.00, p = 0.01). Quadriceps strength was associated with dynamic balance stability (60 °/s, r = − 0.578, p <  0.01; 180 °/s, r = − 0.439, p <  0.01).

Conclusions

For patients with knee OA, the more painful knee was associated with weaker quadriceps and poor balance ability. To improve lower limb function and balance stability of the older persons having knee OA, physicians should take the optimal pain management strategy.

Electronic supplementary material

The online version of this article (10.1186/s12877-018-0932-y) contains supplementary material, which is available to authorized users.

Preoperative factors related to the ambulatory status at 1 year after total knee arthroplasty

PURPOSE

The purpose of this study is to investigate whether preoperative factors can predict the ambulatory status at 1 year after primary total knee arthroplasty (TKA).

METHODS

The subjects were 115 patients who had undergone TKA. Isometric lower limb muscle strength was measured and the Timed Up and Go (TUG) test and the 2011 knee society scoring were conducted preoperatively. Then, the patients were divided into two groups after surgery: a cane-assisted walking group (n = 42) and independent walking group (n = 73). Unpaired t-test, chi-square test, Mann-Whitney U-test, logistic regression analysis and the receiver-operating characteristic curve analysis were used in this study.

RESULTS

A multiple logistic regression analysis selected age, TUG test and functional activities as significant variables estimating the use of a cane after surgery. Receiver-operating characteristic curve analyses revealed that the cut-off score for TUG test was 10.8 s (sensitivity = 69%, specificity = 67%, area under curve = 0.81) and the cut-off score for functional activities was 39 points (sensitivity = 83%, specificity = 63%, area under curve = 0.83) in predicting the ambulatory status.

CONCLUSIONS

Preoperative TUG test with a cut-off score of 10.8 s and functional activities with a cut-off score of 39 points are reliable assessment tools for predicting the use of walking aid following TKA. Implications for Rehabilitation An accurate prediction of the ambulatory status after total knee arthroplasty can aid patients in understanding their own goals of the activities of daily living. Preoperative timed up and go test of <10.8 s and a preoperative functional activities functional activities score in the 2011 knee society scoring >39 points are useful for predicting the ambulatory status after total knee arthroplasty.

Preoperative gluteus medius muscle atrophy as a predictor of walking ability after total hip arthroplasty

PURPOSE

To elucidate the relation between certain preoperative physical parameters and walking with a limp after total hip arthroplasty (THA) and determine whether it is possible to predict the walking ability of patients 6 months after THA.

METHODS

The subjects of this study comprised 74 female patients who had undergone unilateral THA. Before surgery, the hip abductor and knee extensor strengths were measured, the cross-sectional areas (CSAs) of the gluteus medius and rectus abdominis muscles were measured, and the Timed Up and Go test was conducted. The patients were then divided into two groups according to gait observation results 6 months postoperatively: walking without a limp (n=37) and walking with a limp (n=37).

RESULTS

The discriminating criteria between the two groups were age (61 years), CSA of the gluteus medius muscle (2000 mm2), and CSA of the rectus abdominis muscle (340 mm2). In the multiple logistic regression analysis, the gluteus medius muscle was the only significant predictor of limping after THA (β=1.64, R2=0.19, p<0.01).

CONCLUSIONS

The results of the present study suggest that preoperative atrophy of the gluteus medius is an useful indicator for predicting walking with a limp 6 months postoperatively.

The effect of a combined strength and proprioceptive training on muscle strength and postural balance in boys with intellectual disability: An exploratory study

The aim of our study was to investigate the effect of a combined strength and proprioception training (CSPT) program on muscle strength and postural balance in children with intellectual disability (ID). The maximum voluntary contraction (MVC) and postural parameters (CoPVm, CoPLX, CoPLY) of 20 children with ID were recorded before and after 8 weeks of a CSPT program. The participants were divided into two groups: an experimental group who attended a CSPT program and a control group who continued with daily activities. In the trained group, the MVC increased significantly (p<0.001) after the training period and the postural parameters decreased significantly in Double-Leg Stance (DLS) and One-Leg Stance (OLS) during the firm surface condition as well as in the DLS during the foam surface condition; in both eyes open (EO) and eyes closed (EC) conditions. A CSPT program improves postural balance in children with ID could be due to the enhancement in muscle strength and proprioceptive input integration.

Proprioception and Knee Arthroplasty: A Literature Review

Proprioceptive mechanoreceptors provide neural feedback for position in space and are critical for three-dimensional interaction. Proprioception is decreased with osteoarthritis of the knees, which leads to increased risk of falling. As the prevalence of osteoarthritis increases so does the need for total knee arthroplasty (TKA), and knowing the effect of TKA on proprioception is essential. This article reviews the literature regarding proprioception and its relationship to balance, aging, osteoarthritis, and the effect of TKA on proprioception. Knee arthroplasty involving retention of the cruciate ligaments is also reviewed, as well the evidence of proprioception in the posterior cruciate ligament after TKA.

Center of Pressure Displacement of Standing Posture during Rapid Movements Is Reorganised Due to Experimental Lower Extremity Muscle Pain

Background

Postural control during rapid movements may be impaired due to musculoskeletal pain. The purpose of this study was to investigate the effect of experimental knee-related muscle pain on the center of pressure (CoP) displacement in a reaction time task condition.

Methods

Nine healthy males performed two reaction time tasks (dominant side shoulder flexion and bilateral heel lift) before, during, and after experimental pain induced in the dominant side vastus medialis or the tibialis anterior muscles by hypertonic saline injections. The CoP displacement was extracted from the ipsilateral and contralateral side by two force plates and the net CoP displacement was calculated.

Results

Compared with non-painful sessions, tibialis anterior muscle pain during the peak and peak-to-peak displacement for the CoP during anticipatory postural adjustments (APAs) of the shoulder task reduced the peak-to-peak displacement of the net CoP in the medial-lateral direction (P<0.05). Tibialis anterior and vastus medialis muscle pain during shoulder flexion task reduced the anterior-posterior peak-to-peak displacement in the ipsilateral side (P<0.05).

Conclusions

The central nervous system in healthy individuals was sufficiently robust in maintaining the APA characteristics during pain, although the displacement of net and ipsilateral CoP in the medial-lateral and anterior-posterior directions during unilateral fast shoulder movement was altered.

Development of a Prediction Model to Estimate the Risk of Walking Limitations in Patients with Total Knee Arthroplasty

Objective.

Early and accurate risk prediction of walking limitations after total knee arthroplasty (TKA) is important for clinical and economic reasons. However, to our knowledge, no studies have systematically integrated multiple predictors into a single, clinically practical model. Our study aimed to develop a prediction model to estimate the risk of post-TKA walking limitations.

Methods.

We performed a prospective cohort study of 1096 patients who underwent elective, primary TKA between July 2013 and September 2014. Candidate predictors included patient demographics, surgical factors, and pre- and early (1-mo) post-TKA functional measures. The outcome of interest was self-reported walking limitations at 6 months of post-TKA. We used multivariable proportional odds regression with bootstrap internal validation to develop the model.

Results.

In all, 12% of patients reported walking limitations (maximum walk time ≤ 15 min) at 6 months postsurgery. The main predictors of increasing levels of walking limitations were preoperative walking limitations (overall p < 0.001), higher levels of body mass index [interquartile range (IQR)-OR 1.3, 95% CI 1.2–1.5], lower values of 1-month post-TKA gait speed (IQR-OR 1.9, 95% CI 1.3–2.6), the presence of contralateral knee pain (OR 1.9, 95% CI 1.2–3.0), and the use of a quadstick preoperatively (OR 3.5, 95% CI 1.7–7.3). The prediction model had an optimism-corrected concordance index of 0.71.

Conclusion.

A small but sizable proportion of patients with TKA had persistent mobility limitations. Our prediction model may help to risk-stratify patients, and external validation is required before the model can be used in clinical practice.

Muscle Strength and Changes in Physical Function in Women With Systemic Lupus Erythematosus

OBJECTIVE

Cross-sectional studies have observed that muscle weakness is associated with worse physical function among women with systemic lupus erythematosus (SLE). The present study examines whether reduced upper and lower extremity muscle strength predict declines in function over time among adult women with SLE.

METHODS

One hundred forty-six women from a longitudinal SLE cohort participated in the study. All measures were collected during in-person research visits approximately 2 years apart. Upper extremity muscle strength was assessed by grip strength. Lower extremity muscle strength was assessed by peak knee torque of extension and flexion. Physical function was assessed using the Short Physical Performance Battery (SPPB). Regression analyses modeled associations of baseline upper and lower extremity muscle strength with followup SPPB scores controlling for baseline SPPB, age, SLE duration, SLE disease activity (Systemic Lupus Activity Questionnaire), physical activity level, prednisone use, body composition, and depression. Secondary analyses tested whether associations of baseline muscle strength with followup in SPPB scores differed between intervals of varying baseline muscle strength.

RESULTS

Lower extremity muscle strength strongly predicted changes over 2 years in physical function even when controlling for covariates. The association of reduced lower extremity muscle strength with reduced physical function in the future was greatest among the weakest women.

CONCLUSION

Reduced lower extremity muscle strength predicted clinically significant declines in physical function, especially among the weakest women. Future studies should test whether therapies that promote preservation of lower extremity muscle strength may prevent declines in function among women with SLE.

Therapeutic modalities and postural balance of patients with knee osteoarthritis: systematic review

AbstractObjective The objective of this review was to evaluate the evidence of the influence of therapeutic modalities on postural balance in patients with knee osteoarthritis (OA).Methods A search for published papers on therapeutic modalities was conducted using the Pubmed, Medline, Lilacs and SciELO databases. The keywords “knee” and “balance” in combination with “osteoarthritis” were used as the search strategy. Randomized controlled clinical trials published in the last 10 years in either English or Portuguese were selected. The PEDro scale was applied to assess the quality of the selected clinical trials.Results A total of 46 studies of patients with knee OA were found, of which seven were analyzed in full and 39 were excluded because they did not meet the inclusion criteria. Of the seven studies reviewed, six were considered to have a high methodological quality on the PEDro scale. Several therapeutic modalities were found (physical exercise, hydrotherapy, electrotherapy and manual therapy), and postural balance improved in only three studies.Conclusion The studies included in this systematic review had a high methodological quality, so it can be concluded that the therapeutic modalities used in those studies improved postural balance in patients with knee OA.

Laboratory-based measurement of standing balance in individuals with knee osteoarthritis: a systematic review

BACKGROUND

Laboratory-based measurement of standing balance is used to assess postural control in people with and without pathology, including knee osteoarthritis. However, no summary of available data has been reported in this patient population. This study aimed to summarize available data and testing methods for individuals with knee osteoarthritis.

METHODS

Medline (OvidSP and PubMed), Embase, CINAHL, and Web of Science were searched from 1994 to October 25, 2014 to identify studies containing a quantifiable measure of standing balance. Methodological quality was assessed using a modified 17-item Downs & Black quality index. Studies scoring <50% were eliminated.

FINDINGS

The search strategy initially yielded 1523 unique papers; 21 met all inclusion and quality assessment criteria. The variables measured in three or more of the 21 papers were anteroposterior centre of pressure (COP) velocity, mediolateral COP velocity, mean COP velocity, anteroposterior range of COP, mediolateral range of COP, anteroposterior COP standard deviation, mediolateral COP standard deviation, COP path length, COP area, Biodex anteroposterior score, Biodex mediolateral score, and overall Biodex score. In general, people with knee osteoarthritis exhibited worse standing balance compared to healthy controls. However, there remained much discrepancy in testing procedures across studies.

INTERPRETATION

These findings indicate that people with knee osteoarthritis exhibit altered postural control. However, no conclusions could be made on the differences between radiographic severities. That said, these findings provide an opportunity for future researchers and clinicians to compare their findings with the currently published data.

Muscle strength, muscle mass, and physical disability in women with systemic lupus erythematosus

OBJECTIVE

Data describing relationships between muscle strength, muscle mass, and physical disability among individuals with systemic lupus erythematosus (SLE) are limited. The present study examines the relationship of muscle strength and muscle mass with physical disability among adult women with SLE.

METHODS

A total of 146 women from a longitudinal SLE cohort participated in the study. All measures were collected during an in-person research visit. Lower extremity muscle strength was assessed by peak knee torque of extension and flexion and by chair-stand time. Total lean body mass, appendicular lean mass, and fat mass (kg/m(2) ) were measured by whole-body dual x-ray absorptiometry. Self-reported physical disability was assessed using the Short Form 36 health survey (SF-36) physical functioning subscale, and the Valued Life Activities (VLA) disability scale. Spearman's rank correlation coefficients tested the correlations between muscle strength, muscle mass, and disability scores. Regression analyses modeled the effect of lower extremity muscle strength and mass on SF-36 and VLA disability scores controlling for age, SLE duration, SLE disease activity measured with the Systemic Lupus Activity Questionnaire, physical activity level, prednisone use, body composition, and depression.

RESULTS

On all measures, reduced lower extremity muscle strength was associated with poorer SF-36 and VLA disability scores. Trends persisted after adjustment for covariates. Muscle mass was moderately correlated with muscle strength, but did not contribute significantly to adjusted regression models.

CONCLUSION

Lower extremity muscle strength, but not muscle mass, was strongly associated with physical disability scores. While further studies are needed, these findings suggest that improving muscle strength may reduce physical disability among women with SLE.

A protocol to examine vision and gait in Parkinson's disease: impact of cognition and response to visual cues

Background

Cognitive and visual impairments are common in Parkinson’s disease (PD) and contribute to gait deficit and falls. To date, cognition and vision in gait in PD have been assessed separately. Impact of both functions (which we term ‘visuo-cognition’) on gait however is likely interactive and can be tested using visual sampling (specifically saccadic eye movements) to provide an online behavioural measure of performance. Although experiments using static paradigms show saccadic impairment in PD, few studies have quantified visual sampling during dynamic motor tasks such as gait.

This article describes a protocol developed for testing visuo-cognition during gait in order to examine the: 1) independent roles of cognition and vision in gait in PD, 2) interaction between both functions, and 3) role of visuo-cognition in gait in PD.

Methods

Two groups of older adults (≥50 years old) were recruited; non-demented people with PD (n=60) and age-matched controls (n=40). Participants attended one session and a sub-group (n=25) attended two further sessions in order to establish mobile eye-tracker reliability. Participants walked in a gait laboratory under different attentional (single and dual task), environmental (walk straight, through a door and turning), and cueing (no visual cues and visual cues) conditions. Visual sampling was recorded using synchronised mobile eye-tracker and electrooculography systems, and gait was measured using 3D motion analysis.

Discussion

This exploratory study examined visuo-cognitive processes and their impact on gait in PD. Improved understanding of the influence of cognitive and visual functions on visual sampling during gait and gait in PD will assist in development of interventions to improve gait and reduce falls risk. This study will also help establish robust mobile eye-tracking methods in older adults and people with PD.

Validity and reliability of the community balance and mobility scale in individuals with knee osteoarthritis

BACKGROUND

There is a high incidence of falls in older adults with knee osteoarthritis (OA). Adequate dynamic balance and mobility reduce the risk of falls; however, there are currently no validated, advanced tests of dynamic balance and mobility for individuals with knee OA.

OBJECTIVE

The purpose of this study was to determine the convergent validity, known-groups validity, and test-retest reliability of a dynamic test of balance and mobility, the Community Balance and Mobility Scale (CB&M), in a knee OA population.

DESIGN

A cross-sectional design was used.

METHODS

Twenty-five individuals aged 50 years and older with medial knee OA and an equal number of healthy controls completed the CB&M and other tests of balance and mobility, including the Berg Balance Scale, the Timed "Up & Go" Test, a test of maximal single-leg stance time, and the 10-Meter Walk Test (self-selected and fast walking speed). Convergent validity of balance tests with the CB&M was assessed using Pearson product moment correlation coefficients, and known-groups validity was assessed using independent t tests. Test-retest reliability of the CB&M was assessed using intraclass correlation coefficients (ICCs) and standard error of measurement (SEM).

RESULTS

Scores on the CB&M were significantly correlated with all measures of balance and mobility for those with knee OA. There were significant differences in CB&M scores between groups. Scores on the CB&M were highly reliable in people with knee OA (ICC=.95, 95% confidence interval [95% CI]=0.70 to 0.99; SEM=3, 95% CI=2.68 to 4.67).

LIMITATIONS

Few participants had severe knee OA.

CONCLUSIONS

The CB&M displayed moderate convergent validity, excellent known-groups validity, and high test-retest reliability. The CB&M can be used as a valid and reliable tool to assess dynamic balance and mobility deficits in people with knee OA.

The avoidance model in knee and hip osteoarthritis: a systematic review of the evidence

The avoidance model in patients with knee and hip osteoarthritis (OA) hypothesizes that pain and psychological distress lead to avoidance of activities, and thereby to muscle weakness and activity limitations. This paper systematically reviews the scientific evidence for the validity of this avoidance model. A qualitative data synthesis was used to identify levels of evidence. Sixty studies were included. In knee OA, strong evidence was found that avoidance of activities is associated with activity limitations via muscle weakness (mediation by muscle weakness), strong evidence was found for an association between muscle weakness and activity limitations, and weak evidence was found that pain and psychological distress are associated with muscle weakness via avoidance of activities (mediation by avoidance). In hip OA, weak evidence was found for mediation by muscle weakness; and strong evidence was found for an association between muscle weakness and activity limitations. More research is needed on the consecutive associations between pain or psychological distress, avoidance of activities and muscle weakness, and to confirm causal relationships.

Assessment of standing balance deficits in people who have undergone anterior cruciate ligament reconstruction using traditional and modern analysis methods

Modern methods of assessing standing balance such as wavelet and entropy analysis could provide insight into postural control mechanisms in clinical populations. The aim of this study was to examine what effect anterior cruciate ligament reconstruction (ACLR) has on traditional and modern measures of balance. Ninety subjects, 45 who had undergone ACLR and 45 matched controls, performed single leg static standing balance tests on their surgical or matched limb on a Nintendo Wii Balance Board. Data were analysed in the anterior-posterior axis of movement, which is known to be affected by ACLR. The traditional measures of path velocity, amplitude and standard deviation were calculated in this plane. Additionally, sample entropy and discrete wavelet transform derived assessment of path velocity in four distinct frequency bands related to (1) spinal reflexive loops and muscle activity, (2) cerebellar, (3) vestibular, and (4) visual mechanisms of postural control were derived. The ACLR group had significantly increased values in all traditional measures and all four frequency bands. No significant difference was observed for sample entropy. This indicated that whilst postural sway was amplified in the ACLR group, the overall mechanism used by the patient group to maintain balance was similar to that of the control group. In conclusion, modern methods of signal analysis may provide additional insight into standing balance mechanisms in clinical populations. Future research is required to determine if these results provide important and unique information which is of benefit to clinicians.

Influence of Isokinetic Strength Training of Unilateral Ankle on Ipsilateral One-legged Standing Balance of Adults

[Purpose] The purpose of the current study was to investigate the changes in one-legged standing balance of the ipsilateral lower limb following unilateral isokinetic strength training. [Subjects and Methods] Thirty healthy adult volunteers were randomly assigned to either a training group or a control group, so that each group included 15 subjects. Subjects in the training group performed unilateral ankle isokinetic exercises of the dominant leg using the Biodex 3 PRO System for a period of four weeks. Ipsilateral one-legged standing balance was evaluated before and after the intervention with three stability indexes of balance using the Biodex System: Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), and Overall Stability Index (OSI). [Results] Comparison of pre- and post-test data revealed significant improvements in strength values (dorsiflexion, plantarflexion, eversion, and inversion) and stability indexes (APSI, MLSI, OSI). [Conclusion] These results suggest that ankle strengthening exercise can be considered as a form of exercise that may assist individuals with improvement of balance.

Osteoarthritis 2012 year in review: rehabilitation and outcomes

Recent scientific advances in the treatment of hip and knee osteoarthritis (OA) relating to education, exercise, weight control and passive non-pharmacological and non-surgical treatments such as manual therapy, orthoses/orthotics and other aids are described.

METHODS

A systematic literature search was performed in Medline from July 2011 to 10 April 2012 using the terms 'osteoarthritis, knee', 'osteoarthritis, hip' rehabilitation, physical therapy, exercise therapy and preoperative intervention; both as text words and as MeSH terms where possible. Trials evaluating rehabilitation interventions were included if they were randomized controlled trials (RCTs) or systematic reviews. Outcome papers were identified by combining the initial search with the terms 'outcome', 'measure*', 'valid*', 'reliabil*' or 'responsiveness'. Outcome studies were included if they contributed methodologically to advancing outcome measurement.

RESULTS

The literature search identified 550 potentially relevant papers. Seventeen RCTs on rehabilitation were selected and the results from these were supported by six systematic reviews. Sixteen outcomes papers were considered relevant, but did not add significantly to current knowledge about outcome measures in OA and so, were not included.

CONCLUSION

The current research focus on non-pharmacological and non-surgical treatments for hip and/or knee OA, when combined in systematic reviews, is improving the available evidence to identify best practice treatment. Education, exercise and weight loss are effective in the long term and supported as cost-effective first-line treatments.

Validity of the Nintendo Wii® balance board for the assessment of standing balance in Parkinson’s disease

Background:

Impaired postural stability places individuals with Parkinson’s at an increased risk for falls. Given the high incidence of fall-related injuries within this population, ongoing assessment of postural stability is important.

Objective:

To evaluate the validity of the Nintendo Wii® balance board as a measurement tool for the assessment of postural stability in individuals with Parkinson’s.

Subjects:

Twenty individuals with Parkinson’s participated.

Intervention:

Subjects completed testing on two balance tasks with eyes open and closed on a Wii® balance board and biomechanical force platform.

Main Measures:

Bland–Altman plots and a two-way, random-effects, single measure intraclass correlation coefficient model were used to assess concurrent validity of centre-of-pressure data.

Results:

Concurrent validity was demonstrated to be excellent across balance tasks (intraclass correlation coefficients = 0.96, 0.98, 0.92, 0.94).

Conclusions:

This study suggests that the Wii® balance board is a valid tool for the quantification of postural stability among individuals with Parkinson’s.

WiiFit™ Plus balance test scores for the assessment of balance and mobility in older adults

The Nintendo Wii™ is becoming an increasingly popular technology for the training and assessment of balance in older adults. Recent studies have shown promising results for its use in fall prevention. However, it is not clear how scores on the WiiFit™ balance games relate to current standardized tests of balance and mobility. The purpose of this study was to evaluate the relationship between WiiFit™ Plus balance tests, and standardized tests of older adult fitness, balance, mobility, self-reported balance confidence, and visual attention and processing. Results from 34 older adult participants indicate that WiiFit™ balance tests do not correlate well with standardized functional balance, mobility and fitness tests. However, the Wii balance score, as measured by the Basic Balance Test of the WiiFit™, does correlate with visual processing speed as measured by the Useful Field of View (UFOV(®)) test. These results indicate that WiiFit™ balance tests may provide advantageous information supplementary to information obtained through standard functional mobility and balance tests; however, caution should be used when using the WiiFit™ balance tests in isolation. Further research is necessary as these technologies become widely used in clinical and home settings for balance training and assessment.

Validity of the Microsoft Kinect for assessment of postural control

Clinically feasible methods of assessing postural control such as timed standing balance and functional reach tests provide important information, however, they cannot accurately quantify specific postural control mechanisms. The Microsoft Kinect™ system provides real-time anatomical landmark position data in three dimensions (3D), and given that it is inexpensive, portable and simple to setup it may bridge this gap. This study assessed the concurrent validity of the Microsoft Kinect™ against a benchmark reference, a multiple-camera 3D motion analysis system, in 20 healthy subjects during three postural control tests: (i) forward reach, (ii) lateral reach, and (iii) single-leg eyes-closed standing balance. For the reach tests, the outcome measures consisted of distance reached and trunk flexion angle in the sagittal (forward reach) and coronal (lateral reach) planes. For the standing balance test the range and deviation of movement in the anatomical landmark positions for the sternum, pelvis, knee and ankle and the lateral and anterior trunk flexion angle were assessed. The Microsoft Kinect™ and 3D motion analysis systems had comparable inter-trial reliability (ICC difference=0.06±0.05; range, 0.00-0.16) and excellent concurrent validity, with Pearson's r-values >0.90 for the majority of measurements (r=0.96±0.04; range, 0.84-0.99). However, ordinary least products analyses demonstrated proportional biases for some outcome measures associated with the pelvis and sternum. These findings suggest that the Microsoft Kinect™ can validly assess kinematic strategies of postural control. Given the potential benefits it could therefore become a useful tool for assessing postural control in the clinical setting.