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

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.

Factors associated with subjective knee joint stiffness in people with knee osteoarthritis: A systematic review

INTRODUCTION

Subjective knee stiffness is a common symptom in patients with knee osteoarthritis treated conservatively. However, the influencing factors or effects of knee joint stiffness are unknown. The aim of this study was to explore the factors associated with subjective knee stiffness in patients with knee osteoarthritis.

METHODS

The MEDLINE, Cochrane Central Register of Controlled Trials, EMBASE, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and PEDro databases were searched in November 2021. Prospective or retrospective cohort studies were included. The methodological quality of the selected articles was assessed using the Scottish Intercollegiate Guidelines Network checklist.

RESULTS

Twenty out of 1943 screened articles were included in this systematic review. Eighteen and two studies were rated as having acceptable and low quality, respectively. All the included studies measured subjective knee stiffness using the Western Ontario and McMaster Universities Osteoarthritis Index. The main findings were that worse preoperative subjective knee stiffness was associated with worse pain, subjective knee stiffness, and patient satisfaction at 1 year after total knee arthroplasty. In addition, worse subjective knee stiffness was associated with future degenerative changes in the knee joint, such as joint space narrowing and osteophyte growth progression.

CONCLUSION

Subjective knee stiffness may be associated with the prognosis after total knee arthroplasty and degenerative changes in the knee joint. Early detection and treatment of knee stiffness could lead to a good prognosis after total knee arthroplasty and prevent the progression of degenerative changes in the knee joint.

Factors Correlated With Physical Function 1 Year After Total Knee Arthroplasty in Patients With Knee Osteoarthritis: A Systematic Review and Meta-analysis

IMPORTANCE

More than 1 in 5 patients do not experience improved physical function after total knee arthroplasty (TKA). Identification of factors associated with physical function may be warranted to improve outcomes in these patients.

OBJECTIVE

To identify preoperative and intraoperative factors associated with physical function at 12 months after TKA in a systematic review and meta-analysis.

DATA SOURCES

Data from January 2000 to October 2021 were searched in Medline, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Library, and Physiotherapy Evidence Database (PEDro). No language restrictions were applied.

STUDY SELECTION

Prospective observational studies or randomized clinical trials on factors associated with physical function after TKA in adult patients with osteoarthritis were selected. A prespecified peer-reviewed protocol was followed.

DATA EXTRACTION AND SYNTHESIS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses guideline, 2 reviewers independently screened titles and abstracts and judged risk of bias using Quality in Prognosis Studies (QUIPS). Multivariate random-effects meta-analyses were performed to estimate mean correlations between factors and physical function with 95% CIs. Sensitivity analyses were conducted for each QUIPS domain. Certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluations (GRADE). This study was registered with the International Prospective Register of Systematic Reviews (PROSPERO).

MAIN OUTCOMES AND MEASURES

The primary outcome was physical function 12 months after TKA. Secondary outcomes were physical function 3 and 6 months after TKA. All estimates are mean correlations between factors and postoperative function. Positive correlations correspond to better function.

RESULTS

Among 12 052 articles, 20 studies (including 11 317 patients and 37 factors) were analyzed. Mean correlation with higher BMI was estimated to be -0.15 (95% CI, -0.24 to -0.05; P = .33; moderate-certainty evidence), while mean correlation with better physical function was estimated to be 0.14 (95% CI, 0.02 to 0.26; P = .03; low-certainty evidence) and mean correlation with more severe osteoarthritis was estimated to be 0.10 (95% CI, 0.01 to 0.19; P = .17; high-certainty evidence). In sensitivity analyses, mean correlation with better physical function was estimated to be 0.20 (95% CI, 0.04 to 0.36; P = .02), and so perhaps a larger coefficient than in the main analysis, while mean correlations were estimated to be similar for other factors (BMI: -0.17; 95% CI, -0.28 to -0.06; P < .001; osteoarthritis severity: 0.10; 95% CI, -0.01 to 0.20; P = .05).

CONCLUSIONS AND RELEVANCE

This study found that higher presurgical BMI was correlated with worse physical function (with moderate certainty) and that better physical function (low certainty) and osteoarthritis severity (high certainty) were correlated with better physical function after TKA. These findings suggest that these factors should be included when testing predictive models of TKA outcomes.