The Effect of Proximal Femur Morphology on Rates of Periprosthetic Fracture in Patients Undergoing Uncemented Hemiarthroplasty

Objectives Femoral neck fractures are a common injury, particularly in our aging population. These injuries are frequently treated with hemiarthroplasty, which often yields a positive outcome for patients. However, periprosthetic fracture represents a devastating potential complication of this procedure that confers substantial mortality and morbidity. To better understand risk factors for this sequela, we investigated the association between proximal femur morphology, cortical thickness index (CTI), and periprosthetic fracture following uncemented hemiarthroplasty. Methods A retrospective chart review of 97 patients at a single institution who underwent hemiarthroplasty from 2011 to 2021 was conducted. These patients were stratified according to proximal femur morphology using the Dorr classification system, using measurements derived from radiographs obtained at the time of injury. The mean CTI at the time of the procedure was also calculated. Results Overall, the incidence of periprosthetic fracture was 5.2% (5/97). We found that the rate of periprosthetic fracture was highest in those with Dorr C proximal femur morphology (7.7%) and lowest in those with Dorr A proximal femur morphology (0%), although this result did not achieve statistical significance (P=0.66). In contrast, the mean CTI among patients who experienced periprosthetic fracture was approximately 19% lower than that of the comparison group (0.42 versus 0.52, P=0.006). Conclusion The results of this study suggest that the cortical thickness index, but not the Dorr classification of proximal femur morphology, is associated with periprosthetic fracture following uncemented hemiarthroplasty.