Introduction: We aim to review the incidence and risk factors for the development of intraoperative periprosthetic femur fractures while performing a bipolar hemiarthroplasty for displaced neck of femur fractures. Our secondary aim is to characterize the types of intraoperative periprosthetic fractures, the steps leading to the fractures, and the salvage treatments instituted.
Materials and methods: 271 patients treated with bipolar hemiarthroplasty after traumatic displaced femoral neck fractures were retrospectively analyzed. Demographic data, co-morbidities, vitamin D level, consumption of steroids, ASA score, surgical approach, surgeon experience, use of cemented or uncemented implants, proximal femur morphology, and types of anaesthesia were analyzed statistically.
Results: There were 28 patients (10.3%) with intraoperative periprosthetic femur fractures. We found two significant independent risk factors which were the use of uncemented prosthesis (OR 4.15; 95% CI 1.65-10.46; p = 0.003) and Dorr type C proximal femurs (Dorr A OR 3.6; 95% CI 1.47-8.82; p = 0.005). In addition, patients with Dorr type C proximal femurs who underwent uncemented bipolar hemiarthroplasty were more likely to sustain an intraoperative periprosthetic fracture (14(73.7%) out of 19 patients; p = 0.002). There were no significant differences found in other risk factors. The most common location for these fractures was at the greater trochanter at 11 (39.3%) cases. Majority of them, 15 (53.6%), had intraoperative fractures during trial implant insertion and reduction.
Conclusion: The overall incidence of intraoperative periprosthetic femur fractures during hemiarthroplasty for displaced neck of femur fractures was 10.3%. The incidence was significantly higher for uncemented (14.7%) when compared to cemented prosthesis (5.4%) and the greater trochanter was the commonest area for periprosthetic fractures during trial implant insertion and reduction. Uncemented prosthesis and Dorr type C proximal femurs were two significant independent risk factors contributing to intraoperative periprosthetic fractures. By identifying these risk factors, surgeons can take ample precautions to prevent complications.
Keywords: Femoral neck fracture; Hemiarthroplasty; Intraoperative periprosthetic femur fracture; Risk factors.