Associations of self-report physical function with knee strength and knee range-of-motion in total knee arthroplasty possible nonlinear and threshold effects

Clinical Interpretability of Quadriceps Strength and Gait Speed Performance in Total Knee Arthroplasty: A Longitudinal Study

OBJECTIVE

After a total knee arthroplasty, physical assessments of quadriceps strength and gait speed performance are often undertaken during rehabilitation. Our study aimed to improve their clinical interpretability by examining trajectory curves across levels of self-reported walking and stair climbing function.

DESIGN

A sample of 2624 patients with primary total knee arthroplasty participated in this retrospective longitudinal study. Monthly, for 4 mos after surgery, quadriceps strength and gait speed were quantified. At the month-6 time point, self-reported walking and stair climbing function was measured.

RESULTS

All physical measures improved nonlinearly over time. In mixed-effects models, greater quadriceps strength and gait speed over time were associated with higher month-6 self-reported walking and stair climbing function ( P < 0.001). Steeper gains in quadriceps strength and gait speed were associated with higher levels of walking and stair-climbing function (interaction P < 0.001). Among female patients who had great difficulty with stair ascent and ambulation, quadriceps strength trajectory curves plateaued after 8 wks after total knee arthroplasty.

CONCLUSIONS

By stratifying trajectory curves across clinically interpretable functional levels, our findings potentially provide patients and clinicians a means to better interpret the continuous-scaled quadriceps strength and gait speed values. This information may be valuable when engaging patients in shared decision making and expectation setting.

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) Understand how self-reported walking and stair climbing abilities improved from baseline before total knee arthroplasty (total knee arthroplasty) to 6 mos postoperatively; (2) Describe the time course of the 2 performance-based measures of quadriceps strength and walking speed after a total knee arthroplasty; and (3) Relate the trajectories of post-total knee arthroplasty quadriceps strength and walking speed measurements across distinct levels of self-reported walking and stair climbing function.

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.

Knee Osteoarthritis Patients Can Provide Useful Estimates of Passive Knee Range of Motion: Development and Validation of the Copenhagen Knee ROM Scale

BACKGROUND

Knee arthroplasty does not always require extensive long-term follow-up. If knee range of motion (ROM) could be assessed reliably by patients, some follow-up visits might be replaced by patient-reported outcome measures, and this additional information could be reported directly to registers. We developed and tested the validity and reliability of a simple scale for patients to self-report their passive knee ROM.

METHODS

Through an iterative process, we created a 2-item scale with 11 illustrations of knee motion in 15° increments. The validity and reliability was tested in knee osteoarthritis and arthroplasty patients at different treatment stages, many with poor ROM. Patient estimates were compared to passive goniometer measurements performed blindly by a physiotherapist and a junior orthopedic surgeon.

RESULTS

The mean difference between 100 patients' (70.9 years) estimates and goniometer measurements was -0.7° (standard deviation, 12.3°) for flexion and 1.1° (standard deviation, 11.6°) for extension, both not significant. Correlation was 0.79 and 0.63, and kappa values at retest were 0.84 and 0.66. For flexion < 110°, sensitivity of patient estimates was 88% and specificity was 88%. For a limit of 100°, values were 95% and 81%. For extension deficits >10°, sensitivity was 78% and specificity 70%. Values were 100% and 66% for a 15° limit.

CONCLUSION

The Copenhagen Knee ROM Scale is a patient-friendly and feasible alternative to passive ROM measurement for registers, research, and selected clinical use. This scale appears reliable and valid compared to reports of similar tools, and patient estimates are better correlated to goniometer measurements.

Characterizing the recovery trajectories of knee range of motion for one year after total knee replacement

Design: Retrospective analysis of routinely collected clinical data. Objective: This study modeled the recovery in knee flexion and extension range of motion (ROM) over 1 year after total knee replacement (TKR). Background: Recovery after TKR has been characterized for self-reported pain and functional status. Literature describing target knee ROM at different follow-up periods after TKR is scarce. Methods: Data were extracted for patients who had undergone TKR at a tertiary care hospital at 2, 8, 12, 26, and 52 weeks after TKR. A linear mixed-effects growth model was constructed that investigated the following covariates age, sex, pre-TKR range, body mass index, duration of symptoms, and their interaction with weeks post TKR. Results: Of the 559 patients included (age 64.8 ± 8.5 years), 370 were women and 189 were men. Knee ROM showed the greatest change during the first 12 weeks after TKR, plateauing by 26 weeks. For an average patient, knee flexion increased from approximately 100º 2 weeks post TKR to 117º 52 weeks post TKR. Knee extension increased from approximately 3º knee flexion 2 weeks post TKR to 1º flexion 52 weeks post TKR. Conclusions: The results showed that the maximum gains in knee ROM should be expected within the first 12 weeks with small changes occurring up to 26 weeks after TKR. In addition, age and presurgery knee ROM are associated with the gains in knee ROM and should be factored into the estimation of expected knee ROM at a given follow-up interval after TKR.

Evaluation of the Wii Balance Board for walking aids prediction: proof-of-concept study in total knee arthroplasty

BACKGROUND AND OBJECTIVES

To provide proof-of-concept for the validity of the Wii Balance Board (WBB) measures to predict the type of walking aids required by inpatients with a recent (≤4 days) total knee arthroplasty (TKA).

METHODS

A cross-sectional sample of 89 inpatients (mean age, 67.0±8 years) with TKA was analyzed. A multivariable proportional odds prediction model was constructed using 8 pre-specified predictors – namely, age, sex, body mass index, knee pain, knee range-of-motion, active knee lag, and WBB-derived standing balance. The type of walking aids prescribed on day 4 post-surgery was the outcome of interest – an ordinal variable with 4 categories (walking stick, narrow- and broad-base quadstick, and walking frame).

RESULTS

Women, increasing body mass index, and poorer standing balance were independently associated with greater odds for requiring walking aids with a larger base-of-support. The concordance-index of the prediction model was 0.74. The model comprising only WBB-derived standing balance had nearly half (44%) the explanatory power of the full model. Adding WBB-derived standing balance to conventional demographic and knee variables resulted in a continuous net reclassification index of 0.60 (95%CI,0.19-1.01), predominantly due to better identification of patients who required walking aids with a large base-of-support (sensitivity gain).

CONCLUSIONS

The WBB was able to provide quantitative measures of standing balance which could assist healthcare professionals in prescribing the appropriate type of walking aids for patients. Further investigation is needed to assess whether using the WBB could lead to meaningful changes in clinical outcomes such as falls.

Quality of Life, Outcome Scores, and Prognostic Factors of Persistent Fixed Flexion Deformity at Six Months after Total Knee Arthroplasty

This study examined quality of life (SF-36), Clinical Knee Society (Function/Knee) score and Oxford Knee score of primary total knee arthroplasty (TKA) patients with persistent fixed flexion deformity (FFD) ≥10° at six months follow-up. Pre-operative and post-operative clinical data of Group 1 (n=95; 0°< FFD<10°), Group 2 (n=39; FFD>10°) and Control (n=209; FFD=0°) were analysed. FFD improvement was maintained in Control and Group 1 at two years while Group 2 demonstrated little change. Flexion decreased at six months before improving at two years post-TKA was noted in all groups. For Control, significant improvements in majority of SF-36's domains except general health were observed. For Groups 1 and 2, significant improvements were observed in SF-36's physical role, physical role functioning, bodily pain, and social role functioning. Vitality improvement was indicated in Group 1 while emotional role functioning was observed in Group 2. Significant improvements in Clinical Knee Society and Oxford Knee scores were also observed in all groups. Multiple regression analysis revealed that pre-operative factors such as gender ( p=0.035) and pre-operative FFD ( p=0.002) were predictors that correlated with FFD improvement. Our results suggested that FFD have significant impact on quality of life and outcome scores and whenever possible, these should be tracked in order to obtain sufficient information for understanding and aiding the recovery of residual FFD patients after TKA.