Periprosthetic fractures of the acetabulum during cup insertion: posterior column stability is crucial.

Periprosthetic hip fractures around acetabular components are rare with little information available to guide surgical management of these complex injuries. A retrospective review of intraoperative isolated acetabular periprosthetic fractures from three tertiary surgical units was done. A total of 32 patients were identified with 9 initially missed. Acetabular components were stable (type 1) in 11 patients with no failures; unstable (type 2) in 12 patients and treated with supplemental fixation. Non-union and displacement were correlated with absent posterior column plating. Missed fractures (type 3) had the highest reoperation rate. Anterior patterns all healed, whereas fractures with posterior column instability had a 67% failure rate. Periprosthetic acetabular fracture can heal successfully with posterior column stability. Plating is mandatory for large posterior wall fragments to achieve osteointegration.