Metal-on-metal total hip arthroplasty with large heads may prevent early dislocation.

UNLABELLED: Postoperative dislocation is one of the major causes of morbidity and failure of total hip arthroplasty. We reviewed 327 patients (377 hips) retrospectively with varying diagnoses and indications but all of whom received large-diameter metal-on-metal prostheses. Two surgical approaches were used: the anterolateral abductor splitting (342 procedures) and a mini-incision posterior approach (35 procedures). Average age at time of surgery was 55.9 years and average followup was 4.0 months. There were 346 (91.8%) primary procedures, 15 (4.0%) conversion procedures, and 16 (4.2%) revisions or reimplantations. The most common preoperative diagnoses included osteoarthritis (250 hips; 66.3%) and avascular necrosis (46 hips; 12.2%). There were 62 (16.4%) patients with high-risk diagnoses for dislocation. The status in terms of postoperative dislocation was known for all patients. During the short followup period, there were no dislocations. Use of large-diameter femoral heads and metal-on-metal articulations decreases the risk of dislocations, making their use a viable choice for primary and revision procedures. LEVEL OF EVIDENCE: Therapeutic study, Level IV-1 (case series). See the Guidelines for Authors for a complete description of levels of evidence.