What Are the Preoperative Outcome Measures That Predispose to Periprosthetic Fractures After Primary Total Knee Arthroplasty?

Abstract

Background: There is little known in the literature about whether preoperative patient-reported outcome measures (PROMs) would affect the risk of periprosthetic fractures (PPFs) after primary total knee arthroplasty (TKA). Our study aims to evaluate the predictive values of PROMs on PPF after primary TKA. We hypothesize that poorer PROMs are associated with a higher risk of PPF after primary TKA.

Methods: We reviewed prospectively collected data in our hospital arthroplasty registry. Patients who sustained PPF after primary TKA between 2000 and 2015 were identified. Forty-two patients were identified and matched for gender, age, and body mass index to a control group of 84 patients who had primary TKA without PPF in a 2:1 ratio. Preoperative demographics, Short Form-36 (SF-36) scores, Oxford Knee score and Knee Society Score were evaluated. Variables of PROMs were entered into a multivariate logistic regression model. A variable was considered to be a significant predictor if its odds ratio was significant at P < .05.

Results: After multivariate regression analysis, SF-36 subdomains of physical functioning (PF) and vitality (VT) were identified as significant predictors for PPFs after primary TKA. A lower SF-36 PF and VT scores were associated with higher risks of sustaining a PPF after primary TKA.

Conclusion: From our study, low preoperative SF-36 PF and VT scores are associated with a higher risk of PPFs after primary TKA. These results can allow the preoperative identification of patients at higher risk of PPF, and appropriate preoperative counseling, optimization, and close follow-up can be instituted for this at-risk group.

Keywords: patient-reported outcome measures; periprosthetic fracture; preoperative; risk factors; total knee arthroplasty.