Predicting poor physical performance after total knee arthroplasty

The impact of preoperative muscle strength on postoperative walking ability in patients undergoing total knee arthroplasty

Although knee extensor muscle strength is strongly associated with postoperative walking ability (PWA) in patients undergoing total knee arthroplasty (TKA), few studies have considered the impact of both knee extensor and flexor muscle strength. This study aimed to determine whether operative side knee flexor and extensor muscle strength before surgery affects the PWA of patients who undergo TKA while accounting for potential covariates. This multicenter retrospective cohort study involved four university hospitals, and patients who underwent unilateral primary TKA were included. The outcome measure was the 5-m maximum walking speed test (MWS), which was completed 12 weeks postoperatively. Muscle strength was measured as the maximum isometric muscle strength required for knee flexor and extensor. Three multiple regression models with a progressively larger number of variables were developed to determine the predictors of 5-m MWS at 12 weeks post-TKA surgery. One hundred thirty-one patients who underwent TKA were enrolled in the study (men, 23.7%; mean age, 73.4 ± 6.9 years). Age, sex, operative side knee flexor muscle strength before surgery, Japanese Orthopaedic Association knee score, and preoperative walking ability were significantly associated with PWA in the final model of the multiple regression analysis ( R2  = 0.35). The current findings suggest that the operative side knee flexor muscle strength before surgery is a robust modifiable predictor of improved PWA. We believe that further validation is needed to determine the causal relationship between preoperative muscle strength and PWA.

Effects of a home-based, exergaming intervention on physical function and pain after total knee replacement in older adults: a randomised controlled trial

Objectives

To investigate the effects of 4 months of customised, home-based exergaming on physical function and pain after total knee replacement (TKR) compared with standard exercise protocol.

Methods

In this non-blinded randomised controlled trial, 52 individuals aged 60-75 years undergoing TKR were randomised into an exergaming (intervention group, IG) or a standard exercising group (control group, CG). Primary outcomes were physical function and pain measured before and after (2 months and 4 months) surgery using the Oxford Knee Score (OKS) and Timed Up and Go (TUG) test. Secondary outcomes included measures of the Visual Analogue Scale, 10m walking, short physical performance battery, isometric knee extension and flexion force, knee range of movement and satisfaction with the operated knee.

Results

Improvement in mobility measured by TUG was greater in the IG (n=21) at 2 (p=0.019) and 4 months (p=0.040) than in the CG (n=25). The TUG improved in the IG by -1.9 s (95% CI, -2.9 to -1.0), while it changed by -0.6 s (95% CI -1.4 to 0.3) in the CG. There were no differences between the groups in the OKS or secondary outcomes over 4 months. 100% of patients in the IG and 74% in the CG were satisfied with the operated knee.

Conclusion

In patients who have undergone TKR, training at home with customised exergames was more effective in mobility and early satisfaction and as effective as standard exercise in pain and other physical functions. In both groups, knee-related function and pain improvement can be considered clinically meaningful.

Trial registration number

NCT03717727.

Pre- and Post-Operative Rehabilitation Interventions in Patients at Risk of Poor Outcomes Following Knee or Hip Arthroplasty: Protocol for Two Systematic Reviews

Objective

Total knee (TKA) and hip arthroplasty (THA) are successful procedures in treating end-stage osteoarthritis when nonoperative treatments fail. However, a growing body of literature has been reporting suboptimal outcomes following TKA and THA. While pre- and post-operative rehabilitation is imperative to recovery, little is known about their effectiveness for patients at risk of poor outcomes. In the 2 systematic reviews with identical methodology, we aim to evaluate the effectiveness of (a) pre-operative and (b) post-operative rehabilitation interventions for patients at risk of poor outcomes following TKA and THA.

Methods

The 2 systematic reviews will follow the principles and recommendations outlined in the Cochrane Handbook. Only randomized controlled trials (RCTs) and pilot RCTs will be searched in 6 databases: CINAHL, MEDLINE, Embase, Web of Science, Pedro, and OTseeker. Eligible studies including patients at risk of poor outcomes and evaluating rehabilitation interventions following and preceding arthroplasty will be considered for inclusion. Primary outcomes will include performance-based tests and functional patient-reported outcome measures, and secondary outcomes will include health-related quality of life and pain. The quality of eligible RCTs will be evaluated using the Cochrane's risk of bias tool, and the strength of evidence will be assessed using the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE).

Discussion

These reviews will synthesize the evidence regarding the effectiveness of pre-and post-operative rehabilitation interventions for patients at risk of poor outcomes, which in turn may inform practitioners and patients in planning and implementing the most optimal rehabilitation programs to achieve the best outcomes after arthroplasty.

Systematic Review Registration

PROSPERO CRD42022355574.

Association of preoperative muscle composition of the lower extremity with gait function after total knee arthroplasty

BACKGROUND

Limitations of gait function persist in some patients with knee osteoarthritis after total knee arthroplasty. This study aimed to identify preoperative muscle composition variables of the operated limb associated with postoperative gait function.

METHODS

Longitudinal data from 45 patients who underwent unilateral primary total knee arthroplasty were retrospectively analyzed. Timed Up-and-Go test and gait speed were measured preoperatively and at 3 and 6 months postoperatively. Preoperative muscle composition in the glutei medius and minimus, the quadriceps, the hamstrings, and combination of the hamstrings and quadriceps were evaluated by computed tomography. The area ratio of the individual muscle composition to the total muscle was calculated. The factors associated with Timed Up-and-Go test and gait speed were identified using stepwise regression analysis.

RESULTS

Shorter Timed Up-and-Go test and faster gait speed at each time point correlated with higher lean muscle mass area of the total hamstrings, higher area ratio of lean muscle mass to the total hamstrings or to combination of the hamstrings and quadriceps, and lower area ratio of low density lean tissue or intramuscular adipose tissue to the total hamstrings. Shorter Timed Up-and-Go test at each time point also correlated with higher combined area of lean muscle mass of the hamstrings and quadriceps. Faster gait speed at each time point additionally correlated with lower area ratio of intramuscular fat to the total hamstrings and lower area ratio of lean tissue mass or intramuscular adipose tissue to combination of the hamstrings and quadriceps. Regression analysis using the significant muscle composition variables revealed that the area ratio of lean muscle mass to the total hamstrings was the only predictor of Timed Up-and-Go test and gait speed after operation.

CONCLUSIONS

Preoperative area ratio of ipsilateral lean muscle mass to the total hamstrings could predict gait function after total knee arthroplasty.

Effectiveness of Gamification in Knee Replacement Rehabilitation: Protocol for a Randomized Controlled Trial With a Qualitative Approach

BACKGROUND

Exergames can provide encouraging exercise options. Currently, there is limited evidence regarding home-based exergaming in the postoperative phase of total knee replacement (TKR).

OBJECTIVE

This study aimed to investigate the effects of a 4-month postoperative home-based exergame intervention with an 8-month follow-up on physical function and symptoms among older persons undergoing TKR compared with home exercise using a standard protocol. In addition, a concurrent embedded design of a mixed methods study was used by including a qualitative component within a quantitative study of exergame effects.

METHODS

This was a dual-center, nonblinded, two-arm, parallel group randomized controlled trial with an embedded qualitative approach. This study aimed to recruit 100 patients who underwent their first unilateral TKR (aged 60-75 years). Participants were randomized to the exergame or standard home exercise arms. Participants followed a custom-made exergame program independently at their homes daily for 4 months. The primary outcomes at 4 months were function and pain related to the knee using the Oxford Knee Score questionnaire and mobility using the Timed Up and Go test. Other outcomes, in addition to physical function, symptoms, and disability, were game user experience, exercise adherence, physical activity, and satisfaction with the operated knee. Assessments were performed at the preoperative baseline and at 2, 4, and 12 months postoperatively. Exergame adherence was followed from game computers and using a structured diary. Self-reported standard exercise was followed for 4 months of intervention and physical activity was followed for 12 months using a structured diary. Qualitative data on patients' perspectives on rehabilitation and exergames were collected through laddering interviews at 4 and 12 months.

RESULTS

This study was funded in 2018. Data collection began in 2019 and was completed in January 2022. The COVID-19 pandemic caused an unavoidable situation in the study for recruitment, data collection, and statistical analysis. As of November 2020, a total of 52 participants had been enrolled in the study. Primary results are expected to be published by the end of 2022.

CONCLUSIONS

Our study provides new knowledge on the effects of postoperative exergame intervention among older patients with TKR. In addition, this study provides a new understanding of gamified postoperative rehabilitation, home exercise adherence, physical function, and physical activity among older adults undergoing TKR.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03717727; https://clinicaltrials.gov/ct2/show/NCT03717727.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR1-10.2196/38434.

No correlation between symmetry-based performance measures and patient-related outcome prior to and after total knee arthroplasty

PURPOSE

Standardized outcome measures are crucial for the evaluation of different treatment and rehabilitation regimes in patients after total knee arthroplasty (TKA). Performance-based measures are necessary to capture different aspects of physical function. High reliability and agreement of five performance-based measures were hypothesized to differentiate between measurement error and change in test performance. Secondary outcomes are the correlation of performance-based measurements to KSS and WOMAC prior to surgery (baseline) and 10 weeks thereafter (t3).

METHODS

The test-retest reliabilities and agreements of the 1-m walk test, the stair-climbing test, the timed-up-and-go test, the weight-balanced-chair-rising test and the isometric maximum knee extension force in patients undergoing total knee replacements were studied. The intraclass correlation coefficient was calculated and a Bland-Altman analysis performed.

RESULTS

The weight-balanced-chair-rising test showed a symmetry at baseline = 0.77, 5 ± 1 days after surgery (t1) = 0.50, 9 ± 1 days (t2) = 0.59 and (t3) = 0.80. All performance tests showed high intraclass correlation coefficients (ICC = 0.81-0.99). The 10-m walk test, stair climbing test, and the timed-up-and-go test showed high agreement in the Bland-Altman analysis. The Bland-Altman analysis for the weight-balanced-chair-rising test and isometric knee extension force indicated high agreement at 5 and 9 days postoperatively, but the relative measurement error increased pre- and 10 weeks postoperatively.

CONCLUSION

In conclusion, symmetry, as an important outcome after TKA, is a reliable and rather unique item that should unquestionably be added to established measurements like walking tests or survey-based function assessment. The implementation of standardized performance-based measures to assess physical function in rehabilitation procedures will help to improve the more objectively based assessment of different rehabilitation protocols.

LEVEL OF EVIDENCE

II.

The Value of a Standardized Knee Functional Assessment in Predicting the Outcomes of Total Knee Arthroplasty

Questionnaires and physical tests are tools to determine the ability of an individual to perform tasks of the daily living. In our institution, a standardized knee performance evaluation including patient-reported outcome measures (PROMs) and physical performance tests has been applied to all patients undergoing total knee arthroplasty (TKA). Our goal was to identify which preoperative tools influence the outcomes of a TKA and if physical performance tests can be of value if used along with PROMs in predicting functional outcomes. Classification and regression tree was used to analyze which preoperative factors influence function after TKA. Western Ontario and McMaster Universities Arthritis Index (WOMAC) function (WOMAC-F), 6-minute walk test (6MWT), and timed up and go (TUG) test at the 12th postoperative month were the dependent variables. Age, body mass index, preoperative WOMAC function and pain score, muscle strength, 6MWT, and TUG test score were used as preoperative predictors of dependent variables. TUG ≤19.3 seconds and age <62 years were preoperative predictors of better scores in the WOMAC-F (5.5). Strength of extensor muscles of the nonoperated knee ≥99.43 N·m/kg and 6MWT> 328 m were preoperative predictors of a better postoperative 6MWT (499 m). TUG <12.3 seconds and 6MWT ≥421 m were preoperative predictors of better postoperative TUG (7.3 seconds). Preoperative performance in physical tests had an influence on postoperative outcome scores than PROMs after TKA. Less age, good muscular strength, greater capacity of walking, and smaller TUG times were associated with better outcomes.

Risk Factors for Non-Resilient Outcomes in Older Adults after Total Knee Replacement in the FORCE-TJR Cohort

BACKGROUND

Total knee replacement (TKR) is a common procedure in older adults. Physical resilience may be a useful construct to explain variable outcomes. We sought to define a simple measure of physical resilience and identify risk factors for non-resilient patient outcomes.

METHODS

Secondary analysis of FORCE-TJR cohort study, a prospective registry of total joint replacement. Analysis included 7,239 adults ages 60 or older who underwent TKR between 2011- 2015. Measures included sociodemographic and health factors. Outcomes were categorized as physically resilient versus non-resilient based on the change from baseline to 1-year follow up for three patient-reported outcomes: the physical component summary (PCS), bodily pain (BP), and vitality (VT) from the Short Form-36 (SF-36) subcomponent scores, at pre-op and 1-year post-procedure. Associations were expressed as relative risk of physically non-resilient outcomes using generalized linear regression models, with Poisson distribution and log link.

RESULTS

Age, BMI, and Charlson Comorbidity Index (CCI) were associated with increased risk of physically non-resilient outcomes across PCS, BP, and VT: age, per 5-years for PCS (RR=1.18[1.12-1.23]), BP (RR=1.06[1.01-1.11), and VT (RR=1.09[1.06-1.12]); BMI, per 5 Kg/m 2, for PCS (RR=1.13[1.07-1.19]), BP (RR=1.06[1.00-1.11]), and VT (RR=1.08[1.04-1.11]); and CCI for PCS CCI=1 (RR=1.38[1.20-1.59]), CCI=2-5 (RR=1.59[1.35-1.88]), CCI>=6 (RR=1.55[1.31-1.83]. Household-income >$45,000 associated with lower risk for PCS (RR=0.81[0.70-0.93]), BP (RR=0.80[0.69-0.91],), and VT (RR=0.86[0.78-0.93]).

CONCLUSIONS

We operationalized physical resilience and identified factors predicting resilience after TKR. This approach may aid clinical risk stratification, guide further investigation of causes, and ultimately aid patients through the design of interventions to enhance physical resilience.

Clinical Decision Support Tools for Predicting Outcomes in Patients Undergoing Total Knee Arthroplasty: A Systematic Review

BACKGROUND

Total knee arthroplasty is the standard surgical treatment for end-stage osteoarthritis. Although widely accepted as a successful procedure, approximately 30% of patients are not satisfied due to non-optimal postoperative outcomes. Clinical decision support tools that are able to accurately predict post-surgery outcomes would assist in providing individualized advice or services to help alleviate possible issues, resulting in significant benefits to both the healthcare system and individuals.

METHODS

Five databases (Ovid Medline, Ovid EMBASE, CINAHL complete, Cochrane Library, and Scopus) were searched for the key phrases "knee replacement" or "knee arthroplasty" and "decision support tool," "decision tool," "predict∗ tool," "predict∗ model," "algorithm" or "nomogram." Searches were limited to peer-reviewed journal articles published between January 2000 and June 2019. Reference lists of included articles were examined. Authors came to a consensus on the final list of included articles.

RESULTS

Eighteen articles were included for review. Most models reported low predictive success and inability to externally validate. Both candidate and final predictor variables were inconsistent between studies. Only 1 model was considered strongly predictive (AUROC >0.8), and only 2 studies were able to externally validate their developed model. In general, models that performed well used large patient numbers, were tested on similar demographics, and used either nonlinear input transformations or a completely nonlinear model.

CONCLUSION

Some models do show promise; however, there remains the question of whether the reported predictive success can continue to be replicated. Furthermore, clinical applicability and interpretation of predictive tools should be considered during development.

Factors characterizing gait performance of patients before and soon after knee arthroplasty

[Purpose] For monitoring patients with knee osteoarthritis undergoing knee arthroplasty, the Timed Up and Go and maximum walking speed tests are commonly used. To provide appropriate peri-surgical rehabilitation, we evaluated the factors associated with postsurgical changes in Timed Up and Go and maximum walking speed results. [Participants and Methods] We enrolled 545 knee osteoarthritis patients undergoing either of the following knee arthroplasties: conventional total knee arthroplasty, minimally invasive total knee arthroplasty, and unicompartmental knee arthroplasty. Comfortable Timed Up and Go, maximum Timed Up and Go, and maximum walking speed were measured 2 weeks before and soon after surgery. Factors (gender, age, and surgical mode) that might influence changes in test results were evaluated by multiple regression analysis and a two-factor stratification diagram. [Results] Multiple regression analysis revealed that postsurgical changes in comfortable/maximum Timed Up and Go and maximum walking speed results were associated with age and surgical mode after adjustment for preoperative values. Two-factor diagrams showed that the older the patient, the greater was the slowdown in the Timed Up and Go test performed postoperatively. The levels of slowdown in the postoperative Timed Up and Go and maximum walking speed tests were the smallest in those who underwent conventional total knee arthroplasty, followed by those who underwent minimally invasive and unicompartmental knee arthroplasty. Among patients whose preoperative Timed Up and Go and maximum walking speed were slow, slowdown in Timed Up and Go was pronounced with age, and slowdown in maximum walking speed was higher in conventional total knee arthroplasty. [Conclusion] The changes in Timed Up and Go and maximum walking speed results 2 weeks after knee arthroplasty depended on age and surgical modes. These findings are relevant for the implementation of appropriate peri-surgical rehabilitation.

Improvements in Isokinetic Quadriceps and Hamstring Strength Testing After Focused Therapy in Patients With Flexion Instability

BACKGROUND

There is a paucity of literature to guide non-operative treatment for patients with problems after total knee arthroplasty (TKA). We sought to quantify how quadriceps and hamstring strength could improve with focused physical therapy (PT) and whether improving leg strength may prevent revision surgery for patients with flexion instability (FI) after TKA.

METHODS

This retrospective study included patients diagnosed with FI by one of the 4 fellowship-trained arthroplasty surgeons at a single academic institution. Patients with FI were referred for strength measurements and a focused PT program. In total, 166 patients completed isokinetic testing to quantify their relative quadriceps and hamstring power, torque, and work measures compared to their contralateral leg. Fifty-five (33.5%) patients subsequently completed post-PT isokinetic testing. Statistical analysis was conducted to evaluate strength deficits in the knee with FI.

RESULTS

Patients with FI were found to be 20.5%-38.4% weaker in all strength domains compared to the contralateral leg (P < .001). Patients who completed PT and pre-isokinetic and post-isokinetic testing demonstrated statistically significant gains in all extension metrics by a net range of 24.7%-34.2% (P = .011-.029) and their flexion strength metrics improved by 32.5%-40.2% (P = .002-.005). About 81.9% of patients in this subgroup did not undergo revision TKA. Those subjects who went on to revision did not statistically improve in any strength domain (P = .063-.121).

CONCLUSION

Patients with FI after TKA have significantly weaker quadriceps and hamstrings in the operative compared to contralateral leg. Patients who did not undergo revision knee arthroplasty and completed a formal PT program improved quadriceps and hamstring strength by 30%.

LEVEL OF EVIDENCE

IV (Case series).

Do Sociodemographic Factors Relate to Walking Ability in Individuals Who Underwent Total Knee Arthroplasty?

BACKGROUND AND PURPOSE

Knee osteoarthritis is one of the most common health problems in older adults and total knee arthroplasty (TKA) is able to improve walking ability in these individuals. There have been few studies investigating whether sociodemographic factors influence walking ability after TKA. The aim of this study was to examine which sociodemographic factors relate to walking ability in Japanese older adults following TKA during the acute stage of recovery.

METHODS

This prospective cohort study included 388 participants, from a multicenter database, who underwent TKA. The Timed Up and Go test 2 weeks after TKA was the dependent variable. Sociodemographic factors including age, sex, body mass index, marital status, and academic qualification were independent variables. In addition, type of surgery and severity of osteoarthritis were measured as confounding variables. A hierarchical multiple regression analysis was used to predict the factors that have the greatest influence on walking ability. Models were examined with and without confounding factors.

RESULTS AND DISCUSSION

In the final regression model, older age, conventional TKA approaches, increased severity of Kellgren-Lawrence grade, and women were associated with longer Timed Up and Go time. Academic qualification and marital status were not related to walking ability.

CONCLUSIONS

Our results suggest that age, type of surgery, severity of osteoarthritis, and sex are related to Timed Up and Go time during the acute stage following TKA and need to be assessed.

Limited predictive value of pre-surgical level of functioning for functioning at 3 and 12 months after TKA

PURPOSE

A total knee arthroplasty (TKA) is a cost-effective option to relieve pain and improve knee function in patients suffering from osteoarthritis. However, results differ among patients. The predictive value of pre-surgically assessed factors on the level of functioning after 3 and 12 months was investigated in this study.

METHODS

This study used an inception cohort design and a follow-up of 12 months. One hundred and fifty patients who were to receive a TKA were assessed pre-surgically with an International Classification of Functioning, Disability and Health (ICF) core assessment set: Knee Society Score (KSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short-Form 12 (SF12), Patient-Specific Function Scale (PSFS), range of motion (ROM), quadriceps and hamstring strength and gait parameters. The main outcome measure was WOMAC-Function at 3 and 12 months after surgery.

RESULTS

Pre-surgical physical and mental health on the SF12 and functioning and stiffness on the WOMAC explained 23% of the variance in the level of functioning 3 months after surgery. Pre-surgical knee function measured with the KSS-Knee, and functioning as assessed by WOMAC-Function explained 16% of the variance of the level of functioning 12 months after surgery.

CONCLUSIONS

The results of this study show that better functioning before surgery, less knee stiffness and a better physical and mental health to some extent predict better functioning 3 months after surgery. This effect is less evident at 12 months. This study is clinically relevant since it provides benchmark data for health care providers who want to compare their individual patients.

LEVEL OF EVIDENCE

II.

The Aberdeen Weight-Bearing Test (Knee): a new objective test for anterior knee discomfort

Purpose

We present the Aberdeen Weight-Bearing Test (Knee), an objective test specific for anterior knee discomfort assessed via load bearing. We assess its validity by performing it on normal subjects with no knee symptoms and subjects who had undergone anterograde tibial nailing.

Methods

Two scales are placed parallel on the floor with the dials concealed from the subject. The subject then kneels with one knee on each scale. The weight through each knee is recorded at 0, 15, 30, 45, and 60 s. The proportion of total body weight on each leg at each timepoint is calculated, and a ratio calculated from the values. A value of 1 equates to equal weight on each leg. The test was performed on 53 normal subjects and 38 subjects who had undergone tibial nailing.

Results

In the normal group, no significant difference in mean ratio of weight distribution (left:right) was seen at any timepoint (mean ratio range = 0.98–0.99, p value range = 0.18–0.64). In the tibial nail group, a difference was observed in mean ratio of weight distribution (injured:uninjured) favouring the uninjured leg, reaching significance at 0, 15, 30, and 45 s (mean ratio range = 0.88–0.94, p value range = 0.01–0.02). At 60 s, the mean ratio was 0.93 (p = 0.09).

Conclusion

The Aberdeen Weight-Bearing Test (Knee) is an objective, easily reproducible, specific test for anterior knee discomfort. It produces different results in individuals who have undergone anterograde tibial nailing compared to individuals with no knee symptoms.

The Positive Benefits of Negative Movement Patterns Following Total Knee Arthroplasty

Introduction:

Eccentric (negative) resistance exercise of the legs using specialized machines has been reported to be useful and often superior to standard exercise following total knee arthroplasty (TKA). Movements that utilize body mass and gravity as a mode of eccentric resistance exercise in a more pragmatic rehabilitation paradigm may also be useful in reversing chronic muscle impairments observed years following surgery. This study explores whether an eccentrically biased, body mass resistance exercise induces greater magnitude of sagittal plane extensor angular impulse of the support torque and individual net joint torque contributions during both squatting and lunging movement patterns 6 weeks following TKA.

Methods:

Cross-sectional laboratory-based study design including 10 patients following primary unilateral TKA (6.5 ± 0.8 weeks.). All patients completed 3 trials of the squat and lunge movement pattern under both a concentric and an eccentric condition. Extensor angular impulse of the support torque and net joint torque contributions were calculated by integrating the joint torque versus time curves. A Two-way analysis of covariance was conducted and contracts of clinical interest were computed using Wald posttest. P Values for all pairwise comparisons were adjusted for multiplicity using Bonferroni multiple comparison procedure.

Results:

The eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse during both the squat (P < .001) and lunge (P < .001) movement patterns for the support torques. Similarly, the eccentric condition, compared to the concentric condition, displayed larger magnitude of extensor angular impulse of the hip, knee, and ankle (P < .001) during both movement patterns.

Conclusion:

Eccentrically biased, body mass movement exercises can produce higher levels of extensor angular impulse on the surgical limb in patients early after TKA. Patients in this study were able to tolerate the higher extensor angular impulse demands and performed the eccentrically biased conditions (without specialized machines) that could be beneficial in postoperative rehabilitation.

The effectiveness of the use of a digital activity coaching system in addition to a two-week home-based exercise program in patients after total knee arthroplasty: study protocol for a randomized controlled trial

BACKGROUND

There is consistent evidence that supervised programs are not superior to home-based programs after total knee arthroplasty (TKA), especially in patients without complications. Home-based exercise programs are effective, but we hypothesize that their effectiveness can be improved by increasing the adherence to physical therapy advice to reach an adequate exercise level during the program and thereafter. Our hypothesis is that an activity coaching system (accelerometer-based activity sensor), alongside a home-based exercise program, will increase adherence to exercises and the activity level, thereby improving physical functioning and recovery. The objective of this study is to determine the effectiveness of an activity coaching system in addition to a home-based exercise program after a TKA compared to only the home-based exercise program with physical functioning as outcome.

METHODS

This study is a single-blind randomized controlled trial. Both the intervention (n = 55) and the control group (n = 55) receive a two-week home-based exercise program, and the intervention group receives an additional activity coaching system. This is a hand-held electronic device together with an app on a smartphone providing information and advice on exercise behavior during the day. The primary outcome is physical functioning, measured with the Timed Up and Go test (TUG) after two weeks, six weeks and three months. Secondary outcomes are 1) adherence to the activity level (activity diary); 2) physical functioning, measured with the 2-Minute Walk Test (2MWT) and the Knee Osteoarthritis Outcome Score; 3) quality of life (SF-36); 4) healthcare use up to one year postoperatively and 5) cost-effectiveness. Data are collected preoperatively, three days, two and six weeks, three months and one year postoperatively.

DISCUSSION

The strengths of the study are the use of both performance-based tests and self-reported questionnaires and the personalized tailored program after TKA given by specialized physical therapists. Its weakness is the lack of blinding of the participants to treatment allocation. Outcomes are generalizable to uncomplicated patients as defined in the inclusion criteria.

TRIAL REGISTRATION

The trial is registered in the Dutch Trial Register ( www.trialregister.nl , NTR 5109) (March 22, 2015).

Effects of Group-Based Exercise on Range of Motion, Muscle Strength, Functional Ability, and Pain During the Acute Phase After Total Knee Arthroplasty: A Controlled Clinical Trial

Study Design Prospective observational study including a historical control group. Background The extent to which group-based exercise (G-EXE) improves knee range of motion (ROM), quadriceps strength, and gait ability is similar to that of individualized exercise (I-EXE) at 6 weeks and 8 months after total knee arthroplasty (TKA). However, the benefits of G-EXE for patients during the acute recovery phase after TKA remain unclear. Objective To determine the effects of G-EXE during the acute recovery phase after TKA on knee ROM, quadriceps strength, functional ability, and knee pain. Methods Two hundred thirty-one patients participated in G-EXE in addition to regular ambulation and activities-of-daily-living exercises twice daily during the hospital stay. Outcomes were compared to those of a retrospectively identified, historical control group (I-EXE group [n = 206]) that included patients who performed exercises identical to those performed by the G-EXE group. The outcomes included knee ROM, quadriceps strength, pain intensity, and timed up-and-go test score at 1 month before surgery and at discharge. Analyses were adjusted for age, body mass index, sex, length of hospital stay, and preoperative values. Results Changes in ROM of knee flexion and extension (P<.001) and quadriceps strength (P<.001) were significantly better in the G-EXE group than those in the I-EXE group at discharge. The pain intensity improved more in the G-EXE group than in the I-EXE group at discharge (P<.001). However, the changes in the timed up-and-go scores were not significantly different. Conclusion Patients performing G-EXE in addition to regular ambulation and activities-of-daily-living exercises demonstrated greater changes in knee ROM, quadriceps strength, and knee pain than those performing I-EXE in addition to regular ambulation and activities-of-daily-living exercises. The nonrandomized, asynchronous design decreases certainty of these findings. Level of Evidence Therapy, level 2b. J Orthop Sports Phys Ther 2016;46(9):742-748. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6409.

Do Well-Balanced Primary TKA Patients Achieve Better Outcomes Within the First Year After Surgery?

Some surgically modifiable factors are related to soft tissue balance. With computer-assisted surgery, it is possible to access these variables quantitatively. The aim of this analysis was to study the influence of gap balance on clinical outcomes within the first year after computer-navigated total knee arthroplasty (TKA). Based on navigation data, 3 independent variables reflecting gap balance were used to split the patients in 2 groups. The Knee Society Scores (Function [KSS-F] and Knee [KSS-K]) and the maximal knee flexion (MKF) measured preoperatively and at 3, 6 and 12 months were compared using analyses of variance (2×4 design) for repeated measures. Higher flexion-extension gap equality led to statistically higher KSS-F and KSS-K scores at 1 year (P=.02). Higher medial-lateral flexion gap equality led to superior mean MKF at all measurement points; however the differences were statistically only significant at 3 months (P=.01). The coefficients of variation of the variables used to select the patients were overall very low. With computer-assisted navigation, it is possible to access quantitatively the size of the medial and lateral flexion and extension gaps. Higher flexion-extension gap equality values led to statistically significant better KSS-F and KSS-K scores at 1 year. Higher medial-lateral flexion gap equality values led to better MKF values; however the differences were only statistically significant at 3 months. [Orthopedics. 2016; 39(3):S6-S12.].

Physical Activity Promotes Gait Improvement in Patients With Total Knee Arthroplasty

BACKGROUND

The study aimed to examine whether the improvement in gait function after total knee arthroplasty (TKA) correlated with the amount of physical activity and whether both gait self-efficacy and gait function are predictors of the amount of physical activity up to 6 months after surgery.

METHODS

Eighty-one patients were tested preoperatively and at the first and sixth postoperative months after TKA. Physical performance (timed up and go [TUG], sit to stand, muscle strength) and the modified gait efficacy scale scores were evaluated. The average amount of physical activity during the 6 postoperative months was measured with a pedometer with triaxial accelerometer. Stepwise multiple regression analyses were performed using TUG changes and postoperative physical activity. The discriminative properties of physical activity for improvement in gait function were subsequently investigated by applying a receiver operating characteristic curve analysis.

RESULTS

The multiple regression analyses indicated that the amount of physical activity and the improvement in sit-to-stand time were important in predicting improvement in TUG scores after TKA, and postoperative physical activity up to 6 months was predicted by the modified gait efficacy scale and TUG scores at the first postoperative month. The receiver operating characteristic curve analysis suggests that with a cutoff point of 3053 steps/d, the amount of physical activity may be a good predictive factor for gait function after TKA.

CONCLUSION

The clinical implications are that increases in physical activity can promote improvement in gait function after TKA and present with a solid numerical target for the recommended amount of physical activity.

Risk assessment tools used to predict outcomes of total hip and total knee arthroplasty

This article reviews recently proposed clinical tools for predicting risks and outcomes in total hip arthroplasty and total knee arthroplasty patients. Additionally, we share the Massachusetts General Hospital experience with using the Risk Assessment and Prediction Tool to predict the need for an extended care facility after total joint arthroplasty.

What preoperative patient-related factors predict inpatient recovery of physical functioning and length of stay after total hip arthroplasty? A systematic review

Objective:

To identify the preoperative patient-related characteristics predicting inpatient recovery of functioning and/or length of hospital stay after elective primary total hip arthroplasty.

Design:

A search was conducted of the electronic databases MEDLINE, EMBASE and CINAHL from inception through April 2014. Observational studies were selected for systematic review if they identified clinically relevant preoperative prognostic factors and reported an association between inpatient recovery of physical functioning and/or length of hospital stay. Study participants were adults undergoing an elective primary total hip arthroplasty.

Results:

Fourteen studies were included, a total of 199,410 individual total hip arthroplasty procedures. Two studies investigated inpatient recovery of physical functioning, no strong level of evidence was found for a relationship between functional recovery and any of the preoperative predictors. Twelve studies investigated the length of hospital stay and reported 19 preoperative prognostic factors. A strong level of evidence suggested that higher scores on the American Society of Anaesthesiologists assessment (OR 3.34 to 6.22, +0.20 days), increased number of comorbidities (RR of 1.10, +0.59 to 1.61 days), presence of heart disease, (RR of 1.59, +0.26 days), and presence of lung disease (RR of 1.30, +0.34 days) were associated with longer lengths of hospital stay following total hip arthroplasty.

Conclusion:

For the prediction of inpatient recovery of physical functioning no factors with a strong level of evidence were found. For length of stay there was a strong level of evidence for the American Society of Anaesthesiologists score, number of comorbidities, and presence of heart or lung disease.

The effect of payer type on clinical outcomes in total knee arthroplasty

This was a retrospective cohort analysis of 112 patients undergoing primary total knee arthroplasty, wherein baseline demographics, resource utilization, and outcomes were compared by insurance type: Medicaid, Medicare, or private. At the time of surgery, Medicaid patients were younger (P<.0001) and had lower preoperative Knee Society Scores than Medicare and private patients (P=.0125). Medicaid postoperative scores were lower than those of private patients (P=.0223). The magnitude of benefit received by Medicaid patients was similar to Medicare and private patients. Medicaid patients had a higher number of cancelled (P=.01) and missed (P=.0022) appointments relative to Medicare and private patients. Medicaid patients also had shorter average follow-up periods compared to private patients (P=.0003). Access to care and socioeconomic factors may be responsible for these findings.

Predicting acute recovery of physical function following total knee joint arthroplasty

The objective was to explore predictors of physical function during acute in-patient rehabilitation within a few days after TKA. Physical function status of participants (n = 72) three days after total knee arthroplasty (TKA) was measured using the Timed Up and Go Test (TUG) and the function subscale of the Western Ontario McMaster Universities Index of Osteoarthritis (WOMAC-function). Potential predictors of physical function were measured day one post-TKA. Their relationship with physical function was examined using backward elimination, multiple regression analyses. Older age and increased comorbidity were associated (R(2) = 0.20) with worse TUG times. Increased pain severity was associated (R(2) = 0.08) with worse WOMAC-function scores. Age, comorbidity, and pain severity should be considered when predicting which patients will struggle with acute recovery post-TKA.

Indoor and Outdoor Mobility following Total Knee Arthroplasty

PURPOSE

To determine the relationship between indoor and outdoor mobility capacity in older adults with unilateral total knee arthroplasty (TKA) and, secondarily, to determine walking intensity in the same population and to compare all outcomes to a control group of older adults without knee pathology.

METHOD

In this cross-sectional study, participants (TKA=16, mean 22.9 (SD 9.7) mo post TKA; control=22) completed indoor walking tests and a 580 m outdoor course that included varying terrain (e.g., curbs, grass, sidewalk) and frequent changes in direction. Walking capacity was assessed using stopwatches, global positioning system watches and accelerometers.

RESULTS

Outdoor walking time was moderately correlated (p<0.05) with the timed up-and-go (TUG) test (r=0.65), stair-climb test (SCT) (r=0.67 ascending, r=0.79 descending), 10 m walk test (10 mWT) (r=0.73), and 6-minute walk test (6 MWT) (r=-0.75). Based on activity counts, walking intensity levels for participants in both groups were moderate (outdoor walk and 6 MWT). There was no significant difference in walking capacity between groups (TUG, SCT, 10 mWT, 6 MWT, outdoor walk).

CONCLUSIONS

Common clinical walking tests are moderately correlated with outdoor mobility. Mobility capacity of individuals post TKA was similar to controls in both indoor and outdoor environments, and participants in both groups achieved moderate physical activity levels with walking.

Is bicompartmental knee arthroplasty more favourable to knee muscle strength and physical performance compared to total knee arthroplasty?

PURPOSE

Bicompartmental knee arthroplasty features bone and ligament sparing as unicompartmental knee arthroplasty and is presumably better in the recovery of muscle strength and function compared to total knee arthroplasty (TKA) though not previously reported in the literature. The aim of the study was to compare isokinetic knee muscle strength and physical performance in patients who underwent either bicompartmental knee arthroplasty or TKA.

METHODS

Each of 24 patients (31 knees) was prospectively examined preoperatively, at 6 and 12 months after each surgery. Isokinetic knee extensor and flexor strength as well as position sense were measured using the Biodex system. Timed up and go test, stair climbing test, and the 6-min walk test were used to assess physical performance. The results of each group were also compared with those from the corresponding healthy control, respectively.

RESULTS

Demography showed significant difference in the mean age between bicompartment (54.8 ± 5.6 years) and TKA groups (65.7 ± 6.7 years). Comparing between the two groups, knee extensor and flexor torque, hamstring/Quadriceps ratio, position sense, and physical performance were not significantly different preoperatively, at 6 and 12 months after surgery. In intra-group analysis, muscle strength and position sense at each time point were not different in both groups. In physical performance, both groups resulted in improvement in the 6-min walk test, and only TKA group showed enhancement in stair climbing test.

CONCLUSIONS

Although theoretically plausible, bicompartmental knee arthroplasty was not superior in knee muscle strength and physical performance at 1 year compared with total knee arthroplasty.