RESUMEN
OBJECTIVES: To determine risk factors for early conversion total hip arthroplasty (THA) in Pipkin IV femoral head fractures. DESIGN: Retrospective cohort. SETTING: Two level I trauma centers. PATIENTS AND INTERVENTION: One hundred thirty-seven patients with Pipkin IV fractures meeting inclusion criteria with 1 year minimum follow-up managed from 2009 to 2019. MAIN OUTCOME MEASUREMENT: Patients were separated into groups by the Orthopaedic Trauma Association/AO Foundation (OTA/AO) classification of femoral head fracture: 31C1 (split-type fractures) and 31C2 (depression-type fractures). Multivariable regression was performed after univariate analysis comparing patients requiring conversion THA with those who did not. RESULTS: We identified 65 split-type fractures, 19 (29%) underwent conversion THA within 1 year. Surgical site infection ( P = 0.002), postoperative hip dislocation ( P < 0.0001), and older age ( P = 0.049) resulted in increased rates of conversion THA. However, multivariable analysis did not identify independent risk factors for conversion. There were 72 depression-type fractures, 20 (27.8%) underwent conversion THA within 1 year. Independent risk factors were increased age ( P = 0.01) and posterior femoral head fracture location ( P < 0.01), while infrafoveal femoral head fracture location ( P = 0.03) was protective against conversion THA. CONCLUSION: Pipkin IV fractures managed operatively have high overall risk of conversion THA within 1 year (28.5%). Risk factors for conversion THA vary according to fracture subtype. Hip joint survival of fractures subclassified OTA/AO 31C1 likely depends on patient age and postoperative outcomes such as surgical site infection and redislocation. Pipkin IV fractures subclassified to OTA/AO 31C2 type with suprafoveal and posterior head impaction and older age should be counseled of high conversion risk with consideration for alternative management options. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
