Functional characteristics of female patients based on ambulatory ability 1 year after total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is commonly performed to reduce knee pain and improve physical function. Compared with the values for healthy, age-matched women, previous studies have reported large deficits in functional ability, such as muscle strength and ambulatory ability, in women 1 year post-TKA. Ambulatory ability is to move around, particularly by walking and is clinically assessed by the timed up and go test (TUG).

AIM

This study aimed to clarify the characteristics of knee functions in female patients whose ambulatory ability recovered to a normal level at 1 year after TKA.

METHODS

This cross-sectional study included 151 female patients who underwent TKA. The muscle strength of the lower extremity was measured, and the 2011 Knee Society Scoring (2011 KSS) system was used postoperatively. The TUG was conducted to assess ambulatory ability after TKA; then the patients were classified into the fast and slow ambulation groups based on previously reported gait-speed values of healthy female individuals. Then, we identified significant indicators of ambulatory ability at 1 year after TKA.

RESULTS

Forty-nine percent of patients after TKA achieved the level of ambulatory ability of a healthy female. Logistic regression analysis identified that the non-operative side knee extensor strength and the functional activity score, as assessed by the 2011 KSS, were variables significantly associated with the mid-term ambulatory ability after TKA.

CONCLUSION

Female patients with high non-operative knee extensor strength and a functional activity score at 1 year postoperatively can achieve better ambulatory ability than those of healthy, age-matched females.

Clinical prediction model for postoperative ambulatory ability outcomes in patients with trochanteric fractures

INTRODUCTION

Regaining independent ambulatory ability is one of the primary goals of treatment in patients with trochanteric fractures. This study aimed to develop and evaluate the discriminative accuracy of a clinical prediction model for ambulatory ability outcomes 3 months after surgery for trochanteric fractures.

METHODS

This retrospective cohort study included 346 patients treated with intramedullary nailing for trochanteric fractures who had independent ambulatory ability before their injury. Multiple regression models with preoperative and postoperative factors were used to predict ambulatory ability outcomes at 3 months. A clinical prediction model (CPM) was created based on a decision tree developed using a chi-square automatic interaction detector technique.

RESULTS

Three months after surgery, 263 (76.0%) and 83 (24.0%) patients regained and lost independent ambulatory ability, respectively. Univariate analysis showed that the Barthel index (BI) total score at 2 weeks predicted the ambulatory ability outcome at 3 months with good discriminative accuracy (area under the receiver operating characteristic curve [AUROC]: 0.819; 95% confidence interval [CI]: [0.769, 0.868], cut-off value: 22.5; sensitivity: 69.5%; specificity: 82.3%). Multiple logistic regression analysis showed that preoperative factors (residence before injury, diagnosis of dementia, and serum albumin at admission) and postoperative factors (BI total score at 2 weeks) predicted ambulatory ability outcomes at 3 months (AUROC: 0.710; 95%CI: [0.636, 0.783]; sensitivity: 91.3%; specificity: 41.8%). The CPM with the BI total score at 2 weeks (≤10; 10<, ≤50; >50 points) and dementia status (present; absent) had a moderate discriminative accuracy (AUROC: 0.676; 95%CI: [0.600, 0.752]; sensitivity: 94.7%; specificity: 40.5%).

CONCLUSIONS

We developed a CPM with moderate accuracy to predict ambulatory ability outcomes in patients 3 months after surgery for trochanteric fractures. Our results demonstrate the importance of the BI score measured soon after surgery and dementia status for the prediction of postoperative ambulation.