Prevalence of weight-bearing impaction of the femoral head in geriatric acetabular fractures and its role in predicting joint failure.

Abstract

To assess whether weight-bearing impaction of the femoral head may be a valid predictor of joint failure in patients with geriatric acetabular fractures treated with open reduction and internal fixation (ORIF). We retrospectively analyzed data from consecutive elderly patients (including 60 men and 52 women) with acetabular fractures treated with ORIF between January 2015 and January 2022 at the largest orthopedic hospital in western China. The patients had an average age of 69.9 years. Preoperative and postoperative computed tomography scans were evaluated for the presence of medial displacement of the femoral head and femoral head impaction. Impaction of the femoral head was identified on coronal-plane CT images and then classified based on its anatomic characteristics as large, medium, or small. To determine whether total hip arthroplasty (THA) was eventually required over a 24-month follow-up period, binary logistic regression analyses were performed to assess whether impaction of the femoral head was an independent predictor of joint failure in patients with geriatric acetabular fractures treated by ORIF. Impaction of the femoral head was found in 33.9 % (38 out of 112) of all geriatric acetabular fractures. Preoperative and postoperative radiological data, along with the characteristics of acetabular fractures, were compared between patients with impaction (group 1) and those without (group 2). There were no significant inter-group differences in the quality of reduction, acetabular dome impaction, and acetabular fracture type (P > 0.05). Medialization displacement of the femoral head was more frequent in group 1, being present in 76.3 % of weight-bearing impactions (29/38) compared with 23.7 % of those without medialization (9/38). This difference between the two groups was statistically significant. Large or medium impaction was present in 50.0 % (19 out of 38) of the patients with impaction and 84.2 % (16 out of 19) of the patients with joint failure, while small impaction was present in 50.0 % (19 out of 38) of the patients with impaction and 21.1 % (4 out of 19) of the patients with joint failure. Logistic regression analysis revealed that femoral head impaction was significantly and independently associated with a higher risk for joint failure (odds ratio 24.77, P < 0.001). Femoral head impaction frequently occurs in geriatric acetabular fractures, and is a valid predictor of joint failure in patients with geriatric acetabular fractures treated with ORIF. The preferred treatment option for such patients is acute THA, especially if impaction is large or medium.