Background:Hip abductor tendon repair has demonstrated encouraging outcomes. The influence of fatty infiltration (FI) on outcome has not been explored.Purpose:To investigate the association between preoperative hip abductor FI and clinical outcome after hip abductor tendon repair.Study Design:Case series; Level of evidence, 4.Methods:A total of 84 women underwent hip abductor tendon repair. The mean age was 64.6 years (range, 43-84 years); body mass index, 27.7 (range, 20.0-40.2); and duration of symptoms, 3.4 years (range, 6 months–20 years). The 6-minute walk test, isometric hip abduction strength assessment, and patient-reported outcome measures, including the Harris Hip Score and Oxford Hip Score, were completed presurgery and 2 years after surgery. Patient satisfaction and perceived improvement were assessed 2 years after surgery. All patients underwent preoperative magnetic resonance imaging on the affected hip, and the Goutallier system was used to grade the degree of FI in the anterior, middle, and posterior thirds of the gluteus medius and minimus on a 0-4 ordinal scale. A single FI score for the gluteus medius and minimus was calculated, as was a combined FI score.Results:All clinical scores significantly improved over time ( P < .001). Preoperatively, FI was more severe in the gluteus minimus, with the most severe FI (grades 2-4) demonstrated in the middle (n = 56, 66.7%) and anterior (n = 17, 20.2%) portions of the gluteus minimus and the middle (n = 27, 32.1%) and anterior (n = 12, 14.3%) portions of the gluteus medius. Older age was associated with greater FI (combined FI score: r = 0.529, P < .001), although duration of symptoms ( r = 0.035, P = .753) and body mass index ( r = 0.089, P = .464) were not. Greater FI was associated with less improvement in hip strength of the unaffected leg (coefficient, –1.6, 95% CI: −2.8 to −0.4), although no other significant associations were observed between FI and pre- or postoperative clinical scores.Conclusion:Preoperative FI was not associated with pertinent parameters of patient outcome after hip abductor tendon repair, including pain, symptoms, functional capacity, perceived improvement, and satisfaction. Based on these outcomes, surgical repair may be considered in the presence of more severe FI.