To determine risk factors for early conversion total hip arthroplasty (THA) in Pipkin IV femoral head fractures.
Two level I trauma centers
Patients and Intervention:
137 patients with Pipkin IV fractures meeting inclusion criteria with 1-year minimum follow-up managed from 2009-2019.
Main Outcome Measurement:
Patients were separated into groups by 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 to those who did not.
We identified 65 split-type fractures, 19 (29%) underwent conversion THA within 1-year. Surgical site infection (SSI) (p=0.002), post-operative 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.
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 sub-type. Hip joint survival of fractures subclassified OTA/AO 31C1 likely depends on patient age and postoperative outcomes such as SSI and re-dislocation. 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.