A Prospective Randomized Trial of Mini-Incision Posterior and 2-Incision Total Hip Arthroplasty: Minimum 5-Year Follow-Up.

BACKGROUND: We previously described the results of a randomized controlled trial of mini-posterior vs 2-incision total hip arthroplasty and were unable to demonstrate significant differences in early outcomes. As less-invasive anterior approaches remain popular, the purpose of this report was to re-examine the outcomes at a minimum 5-year follow-up.

METHODS: Seventy-two patients undergoing primary total hip arthroplasty were randomized to a mini-posterior or 2-incision approach. Complications, revisions, and clinical outcome measures were compared. Radiographs were reviewed for implant loosening. A power analysis using a minimal clinically important difference value of 6 points for the Harris hip score revealed 28 patients required per group.

RESULTS: At a mean of 8.2 years (range, 5-10 years), 6 patients died without revision surgery and 63 of 66 living patients were reviewed. There were 6 total failures, 3 in each group. For unrevised patients, there were no significant differences between groups (posterior vs 2-incision) in the Harris hip score (95.5 ± 3.5 vs 95.7 ± 6.3; P = .88), 12-item Short Form Survey physical composite score (50.5 ± 8.5 vs 49.0 ± 9.1; P = .53), 12-item Short Form Survey mental composite score (57.3 ± 4.1 vs 55.4 ± 8.0; P = .25), or single assessment numeric evaluation score (97.1 ± 3.7 vs 97.8 ± 5.2; P = .55).

CONCLUSION: We found no differences in midterm outcomes between the 2 approaches. Given the increased complexity, operative time, and need for fluoroscopy with the 2-incision approach combined with equivalent early and midterm outcomes, the 2-incision approach has been abandoned in the senior author's practice.