An unusual pattern of posterior wall fracture of acetabulum

This study aims to describe an uncommon presentation of posterior wall acetabular fracture-dislocation with displacement of fracture fragment anterior to femoral head with its management and clinico-radiological outcome.

This retrospective review was performed at a Level I trauma centre over a period of six years. Hospital records, radiological database, operative register and follow-up data identified 7 patients with anteriorly lying posterior wall fragment of acetabulum. Analysis was performed with 6 patients having complete follow-up ranging from 2 to 7 years. The patients were operated with standard Kocher-Langenbeck approach; modification of this approach with trochanteric flip osteotomy and safe surgical dislocation was performed based on the location of the anteriorly lying fragment. Final functional and radiographic outcome was analysed according to modified Merle D'Aubigné and Postel score, and Matta's grade, respectively.

This uncommon presentation was observed in 11.11% of patients out of 63 patients with isolated posterior wall acetabular fractures managed during the study period. Anteriorly displaced posterior wall fragment was located in anterosuperior (n, 3), anterocentral (n, 2) and anteroinferior (n, 1) quadrants anterior to the femoral head. Final clinical and radiographic outcome revealed good-to-excellent outcome in 5 (83.33%) patients, and poor in one. One patient developed progressive arthrosis of hip which required total hip arthroplasty within 2 years.

This unusual pattern of posterior wall fracture requires adequate pre-operative planning, careful handling of the fractured fragments along with its soft tissue attachments during surgery, and preferably a concomitant trochanteric flip osteotomy with/without surgical hip dislocation to achieve good results.