Objectives: Knee osteoarthritis (KO) is a leading contributor to disability years, with a prevalence ranging from ۲۲% to ۳۹%. 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 ۳:۱ (TKA: TSF) propensity score-matched (PSM). The primary outcome was a PSM comparison of patient-reported outcome measures (PROMs) and ۱-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 ۳۱ patients (۹۶.۹%) in the TSF group compared to ۹۲ patients (۹۵.۸۳%) in the TKA group. MCID for KSS PS was achieved by ۲۹ patients (۹۰.۶۳%) in the TSF group compared to ۹۱ patients (۹۴.۷۹%) 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 ۲-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. Level of evidence: III
