EP7.4 To Lengthen or to Revise: Re-evaluating Anterior Cup Prominence Thresholds in Iliopsoas Impingement s/p THA

Abstract Background Iliopsoas impingement (IPI) is a known cause of persistent anterior hip pain following total hip arthroplasty (THA). Management of IPI has often relied on an 8mm anterior acetabular overhang threshold to guide operative treatment, favoring acetabular revision for greater prominence and iliopsoas tenotomy for lesser prominence. These thresholds were initially established based on the outcomes of open tenotomy, and now with improved understanding of IPI and the advent of arthroscopic iliopsoas fractional lengthening (IPFL), a review of the 8 mm threshold is warranted. Materials A retrospective review was performed to identify patients who underwent arthroscopic IPFL following primary THA between 2017 and 2024, with a minimum of one year of follow-up. Acetabular overhang was measured for all patients using cross-table lateral radiograph and patients were stratified into <8mm and ≥8mm cohorts. Patient-reported outcome measures (PROMs), reoperations, revisions, and complications were collected and analyzed based on both the classic 8 mm threshold using continuous statistical methods. Results Eighty-six hips undergoing IPFL in 83 patients (30 male, 53 females, age: 63.0 ± 11.2) were evaluated. Sixty-seven hips had <8mm of overhang and nineteen had ≥8 mm. Mean follow-up was 2.5 ± 1.6 years (range: 1- 7.5 years). When comparing patients with <8mm and ≥8mm acetabular overhang, there were no significant differences (p ≥0.06) observed between pre- and postoperative VAS pain scores, modified Harris Hip Score, SANE score, Tegner activity level, subjective groin pain improvement, subjective hip flexion strength, and overall satisfaction. Reoperation (2.9 vs. 10.5%, p = 0.210) and acetabular revision rates (1.5 vs. 5%, p = 0.387) were not significantly different between overhang groups. Conclusions Arthroscopic IPFL provides satisfactory outcomes for patients with IPI, independent of degree of acetabular overhang. IPFL should be considered for first-line surgical management of IPI refractory to conservative management, even in the setting of substantial acetabular overhang, given positive outcomes and low rates of subsequent acetabular revision.