Risk of conversion to total knee arthroplasty after surgically treated tibial plateau fractures: an observational cohort study of 439 patients

Abstract

Background and purpose: We aimed to assess joint failure rate, i.e., subsequent conversion to TKA after surgical treatment of a tibial plateau fracture (TPF). Secondary aims were to explore the association between joint failure and fracture type, and to determine the risk of failure associated with inadequate joint surface reduction.Methods: We included all patients ≥ 18 years of age with a surgically treated TPF, treated at Uppsala University Hospital between 2002 and 2015. All fractures were classified according to the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Traumatology Association (AO/OTA) classification. Postoperative radiographs were evaluated to determine the quality of joint surface inadequate reduction, defined as an articular step-off ≥ 2 mm. The study cohort was linked with the Swedish Arthroplasty Register (SAR) for information on subsequent total knee arthroplasty (TKA).Results: 439 patients (57% women) with a mean age of 55 years (SD 17) were included. According to the AO/OTA classification, the fracture distribution was B1: 4.8%, B2: 10%, B3: 47%, C1: 12%, C2: 6.4%, and C3: 19%. 23 patients (5.2%) were converted to a TKA within 2 years of initial surgery, and 34 patients (7.7%) had been converted by the end of follow-up (16 years). AO/OTA type B3 and C3 had a 6.8 (95% confidence interval [CI] 1.6–29) times greater risk of joint failure compared with B1–2 and C1–C2 at 2 years’ follow-up. Inadequate joint surface reduction led to an 8.4 (CI 3.6–20) times greater risk of conversion to TKA at 2 years’ follow-up.Conclusion: Overall, 5.2% were converted to a TKA within 2 years. Fracture types AO/OTA B3 and C3 with a comminuted articular surface and inadequate joint surface reduction were strongly associated with joint failure.