Incidences and Outcomes of Operatively Treated Interprosthetic Femoral Fractures Compared to Vancouver Type C and Rorabeck Type II Fractures.

ABSTRACT

BACKGROUND: This case-control study evaluated the incidences and outcomes of interprosthetic femoral fracture (IPFF) (Group I) and performed comparisons with Vancouver type C (Group II) and Rorabeck type II (Group III) periprosthetic femoral fractures (PPFF) occurring at similar anatomic sites. METHODS: A retrospective analysis was performed for all patients who had a previously implanted total hip arthroplasty (THA) and total knee arthroplasty (TKA), who lived in the hospital district and had undergone surgery due to PPFF. A total of 153 PPFFs [Group I (n = 31), Group II (n = 21), and Group III (n = 108)] were included. The annual incidences of PPFFs were summarized per 100,000 individuals. The risks of complications, reoperations, and mortalities were evaluated for all groups. RESULTS: The mean population-based annual incidence was 0.9 per 100,000 person years for Group I, 0.7 per 100,000 person years for Group II, and 3.1 per 100,000 person years for Group III. A total of 25 of 153 (16%) major complications were found and 23 of 153 (13%) cases resulted in a revision surgery. The cumulative incidence of death in Group I was 50.4% at 10 years, in Group II it was 63.8% at 10 years, and in Group III it was 74.9% at 10 years. CONCLUSION: The annual incidence of the IPFF almost doubled while the incidence of Vancouver type C stayed stable and Rorabeck type II incidence increased 5-fold. Most of the major complications occurred in IPFF group, while Rorabeck type II patients had the worst survival.