Outcomes of Gluteus Maximus Transfer and the High Prevalence of Lumbar Spine Pathology: A Potential Etiology of Abductor Failure.

Abstract

Background: Gluteus maximus tendon transfer has been described as a salvage treatment option for irreparable abductor tendon tears. Current literature has demonstrated favorable short term outcomes, yet strength and gait abnormalities persist. The purpose of this study was to evaluate the impact of gluteus maximus tendon transfer on patient reported outcomes (PROs) over two consecutive time points and determine the prevalence of concomitant lumbosacral pathology.

Methods: A retrospective review of 17 patients who underwent gluteus maximus transfer for irreparable abductor insufficiency was performed. The mean age was 71 years (range, 61 to 83), and 88% (15/17) were women. Clinical outcomes were obtained from follow-up visits, and modified Harris Hip Scores (mHHS) and Visual Analog Scale (VAS) pain scores were obtained at 24.9 ± 8.4 months (range, 13 to 42) and 47.1 ± 9.4 months (range, 31 to 65) postoperatively.

Results: Mean mHHS (46.3 vs. 66.1, P<0.01), VAS at rest (3.1 vs. 0.9, P<0.01), and VAS with activity (5.9 vs. 1.9, P<0.01) improved between preoperative and 24.9 months postoperatively. Between 24.9 months and 47.1 months, mean mHHS (66.1 vs. 53.7, P<0.01) and VAS with activity (1.9 vs. 4.4, P<0.01) declined, and there was no difference in VAS at rest (0.9 vs. 2.1, P=0.09). Compared to the preoperative state, there was maintained improvement in mHHS (46.3 vs. 53.7, P=0.03) but no difference in VAS scores. Lumbar spine pathology or lumbar spine instrumentation was present in 76% (13/17) of patients.

Conclusion: Patients undergoing gluteus maximus transfer for irreparable abductor deficiency demonstrate improved PROs at 2 years postop-eratively. These improvements persist to a variable degree at 4 years. There was a high prevalence of associated lumbar spine pathology suggesting a key etiologic factor explaining why these patients exhibit severe fatty degeneration of the abductor musculature while preserving gluteus maximus function.

Level of evidence: IV.