Predicting Instability Risk Following Hemiarthroplasty for Femoral Neck Hip Fractures in Geriatric Patients.

Area of Science:

• Orthopedic surgery
• Geriatric medicine
• Biomechanical engineering

Background:

• Dislocation following hemiarthroplasty (HA) for femoral neck fractures is a rare but serious complication.
• It increases mortality, readmission rates, and the likelihood of revision surgery.
• Identifying specific risk factors for HA dislocation is crucial for improving patient outcomes.

Purpose of the Study:

• To identify patient, surgical, and morphological risk factors for hemiarthroplasty dislocation in geriatric patients with femoral neck fractures.
• To elucidate the specific predictors of dislocation following HA in this population.

Main Methods:

• Retrospective review of 270 patients undergoing hip fracture surgery.
• Binomial regression predictive models were developed using medical records from 2016-2022.
• Area under the curve (AUC) was used to assess the predictive ability of variables and acetabular anteversion.

Main Results:

• Significant predictors of dislocation included center edge angle (OR 1.23), abduction angle (OR 1.17), and depth width ratio (OR 2.96e-11).
• Cut scores for risk were identified as <44.1° for center edge angle and .298 for depth width ratio.
• Dementia (AUC=0.617) and male sex (AUC=0.558) showed high discriminative ability; acetabular anteversion was not predictive.

Conclusions:

• Morphological factors, specifically hip dysplasia and shallow acetabulum identifiable on radiographs, predict instability after HA in the elderly.
• These radiographic assessments can guide surgical planning to mitigate dislocation risk.
• Implant design, manufacturer, and acetabular version were not found to be significant risk factors for instability.