Common acetabular fracture patterns in patients with femoroacetabular impingement

The incidence of acetabular fractures is rising, affecting both younger and elderly patient populations. Developmental abnormalities such as femoroacetabular impingement (FAI) and hip dysplasia alter hip biomechanics, potentially predisposing younger patients to fracture. FAI, resulting from a cam and/or pincer deformity, is common, affecting 25% of asymptomatic males and 5% of asymptomatic females, and has been linked to hip pain and early osteoarthritis. However, the relationship between FAI morphology and acetabular fracture pattern remains unclear.

Patients, 18-55 years old, treated between 2005 and 2023 for acetabular fracture, hip dislocation, or femoral head fracture were reviewed for FAI morphology using the Judet and Letournel classification systems. Statistical comparisons were conducted using Fisher's exact tests and unpaired t-tests, with significance set at p < 0.05.

A total of 294 patients (72%) exhibited plain radiographic FAI morphology, while 115 (28%) served as controls. The most common fracture pattern in both groups was posterior wall (PW) fractures (23.1% FAI, 31.3% control). Male FAI patients were significantly more likely to experience transverse fractures (p = 0.032, OR=4.6) and posterior column plus PW fractures (p = 0.035, OR=2.5) than controls. Among FAI patients, posterior column fractures were significantly more likely to occur in females (p = 0.011, OR=19). A total of 31 (27.0%) control patients and 63 (21.4%) FAI patients experienced complications.

In our data set, FAI patients accounted for 72% of patients undergoing acetabular fracture ORIF. FAI patients most commonly sustained posterior wall fractures, but male FAI patients had a significantly higher rate of transverse and posterior column plus PW. FAI patients experienced a complication rate of 21.4% compared to 27.0% in non-FAI patients.