Concordance of Dislocation Direction and Surgical Approach Is an Approach-Dependent Risk for Recurrent Instability Following Total Hip Arthroplasty.

BACKGROUND: Hip instability after total hip arthroplasty (THA), while uncommon, is a leading cause for revision. The purpose of the study was to quantify the risk of recurrent hip dislocation in relation to concordance of dislocation directionality and surgical approach. METHODS: Included patients underwent anterior-based or posterior-based elective primary THA and sustained at least one dislocation treated at a single institution. Surgical approach, timing, direction, and management of dislocations, including closed reduction and reoperation, were obtained. Concordance was defined as dislocation in the same direction as the surgical approach. There were 112 patients (114 hips) who experienced dislocation after primary THA between January 1, 2013, and November 1, 2025. Chi-square analyses were performed to assess differences in dislocation recurrence, depending upon approach and dislocation directionality. RESULTS: The posterior approach was most common (62.3%), followed by anterior (27.2%) and direct lateral (10.5%). The median time to first dislocation was 41 days [interquartile range 18, 103.5], and most were posteriorly dislocated (64.9%). There were five patients (4.4%) who required an open reduction and revision after index dislocation. There were 61 patients who experienced at least two dislocations, accounting for 56.0% of patients who were not revised at the initial dislocation. The median time to second dislocation was 97 days [interquartile range 46, 375]. For posterior approaches, 68.4% of posterior dislocations recurred, while just 28.6% of anterior dislocations recurred (P = 0.006). For anterior approaches, 42.3% of posterior dislocations and 41.2% of anterior dislocations recurred (P = 0.94). CONCLUSIONS: Concordance between approach and dislocation directionality is a helpful predictor of recurrence for posterior-based approaches. Recurrent instability occurs in more than half of patients after a single dislocation; thus, indications for revision should be closely scrutinized after an instability event.

Duke Scholars

Author Michael Paul Bolognesi Orthopaedic Surgery

Author Sean Ryan Orthopaedic Surgery

Author Andrew Schwartz Orthopaedic Surgery