Total Knee Arthroplasty in End-Stage Knee Osteoarthritis with Tibia Stress Fractures- A Propensity Score Matched Comparative Study.

Abstract

Objectives: Knee osteoarthritis (KO) is a leading contributor to disability years, with a prevalence ranging from 22% to 39%. Tibia stress fractures (TSFs) are well-described for end-stage arthritis patients undergoing TKA. Literature is ambiguous, with a wide range of management options. This study primarily aims to compare and determine the clinical, functional, and radiological outcomes of TSFs in end-stage KO treated with TKA by propensity score-based matching.

Methods: It is a retrospective, single-center, comparative study conducted at University Teaching Hospital. The institutional medical records (IMRs) database was inquired. The TSF group included all patients of end-stage KO who underwent primary TKA with TSFs, and the TKA group included matched patients without TSF. Cases were 3:1 (TKA: TSF) propensity score-matched (PSM). The primary outcome was a PSM comparison of patient-reported outcome measures (PROMs) and 1-year Postoperative Complications and Adverse Events (POCAE). PROMs included the knee society score (KSS), patient satisfaction (PS), and KSS functional activities (FA) score.

Results: Study includes thirty-seven patients. Both groups showed no statistically significant difference in KSS FA and KSS PS scores. At the final follow-up, MCID for KSS FA was achieved by 31 patients (96.9%) in the TSF group compared to 92 patients (95.83%) in the TKA group. MCID for KSS PS was achieved by 29 patients (90.63%) in the TSF group compared to 91 patients (94.79%) in the TKA group.

Conclusion: End-stage KO patients with coexisting TSFs who undergo primary TKA with stem/ plate fixation as per fracture location may expect favorable PROMs, POAECs, radiological outcomes, and rates of achieving the MCID at a minimum 2-year follow-up. Accurate management of such cases results in excellent outcomes and minimized revision rates. All patients achieved complete bone union. These results were comparable to the PSM control group.