High Rate of Unplanned Reoperation for Interprosthetic Femur Fractures after Total Hip and Knee Arthroplasty

IntroductionInterprosthetic femur fractures (IPFFs) are a rare, but devastating complication following total joint arthroplasty. There is limited evidence to help guide their management. The purpose of this study was to describe the features, treatment, and outcomes of surgically managed IPFFs.MethodsWe retrospectively identified 75 patients who had 76 IPFFs. The mean age at the time of IPFF was 75 years (range, 29 to 94), and 78% were women. The mean body mass index was 30 (range, 19 to 51), and the mean follow-up was 3 years (range, 0 to 14). There were 16 Vancouver B1 fractures, 28 Vancouver B2 fractures, 2 Vancouver B3 fractures, and 30 Vancouver C fractures. All B1 fractures underwent open reduction internal fixation (ORIF). All Vancouver B2 and B3 fractures underwent revision arthroplasty, including 1 proximal femur replacement (PFR) and 1 total femur replacement (TFR). Vancouver C fractures were treated with ORIF (n = 20), distal femoral replacement (DFR) (n = 9), and in one case, TFR (n = 1). Kaplan-Meier survivorship was used to calculate 2-year survival free from all-cause reoperation and periprosthetic joint infection (PJI).ResultsThe 2-year survivorship-free rate from reoperation was 71%. There were 18 reoperations following initial surgical management of the IPFF, including 9 for infection, 3 for re-fracture, 3 for nonunion, 2 for hardware failure, and 1 for instability. An initial IPFF involving a stemmed femoral TKA component was associated with increased risk for reoperation (P = 0.007) and PJI (P = 0.044). There was no difference in survivorship free of reoperation between IPFFs managed with ORIF or revision arthroplasty (P = 0.72).ConclusionAn IPFF is a devastating complication following total joint arthroplasty with high reoperation rates, most commonly secondary to PJI. Those IPFFs that occurred between two stemmed components were at the highest risk for reoperation.