Instability Following Head and Liner Exchange: Eight-Fold Reduction in Dislocation With the Direct Anterior Approach.

Abstract

Isolated head and liner exchange (HLE) can be utilized as a less invasive option for specific indications in revision total hip arthroplasty. Historically, the most common complication following HLE is dislocation. The objective of this study was to determine if the direct anterior approach (DAA) results in a lower incidence of dislocation when compared to the posterolateral approach (PLA) for HLE. A retrospective review identified 176 cases undergoing isolated HLE (129 PLA and 47 DAA) for polyethylene wear between 2016 and 2025. Cases that had a previous periprosthetic joint infection or previous instability were excluded. Cox proportional hazards regressions were used to compare the DAA versus PLA approach in terms of reoperation and dislocation survival outcomes. Femoral head diameter was increased in 74.1% of PLA and 32.4% of DAA. Elevated liners were placed in 45.7% of PLA HLE versus 6.4% of DAA and dual-mobility construct or a constrained liner in 6.9 and 4.7% of PLA, respectively, but in none of the DAA cohort. At 1 year, dislocation incidence was lower after DAA than PLA (2.4 versus 12.4%), with higher dislocation-free survivorship for DAA (log-rank Chi-square = 5.55, P = 0.02; hazard ratio for PLA versus DAA: 7.68, P = 0.04). The 1-year reoperation incidence was 2.7% after DAA versus 6.2% after PLA, with no significant difference in reoperation-free survivorship (log-rank Chi-square = 1.64, P = 0.20; hazard ratio 2.54, P = 0.22). Use of the DAA for isolated HLE was associated with a nearly eight-fold lower risk of dislocation compared to PLA, despite less frequent use of dislocation-mitigating implants in the DAA cohort. Surgeons may consider DAA for HLE to reduce postoperative instability.