Gluteal Tendinopathy Is Associated With Lower Patient-Reported Outcome Measures in Total Hip Arthroplasty With a Posterior Approach: A Prospective Cohort Study of 1,538 Patients.

BACKGROUND: Gluteal tendinopathy (GT) is found in 20 to 25% of patients undergoing total hip arthroplasty (THA). Despite this, there is a scarcity of literature assessing the association between GT and THA outcomes. The aim of this study was to evaluate whether intraoperative diagnosis of GT negatively affected postoperative outcomes.

METHODS: Consecutive patients undergoing primary THA for osteoarthritis via a posterior approach over 5 years were recruited in a prospective study. Gluteal tendinopathy was assessed and graded at the time of surgery, but not repaired. A total of 1,538 (93%) completed the patient-reported outcome measures (PROMs) at 1 year after surgery and were included in the analysis. The PROMs included the Oxford Hip Score (OHS), Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS JR), and EuroQol 5-Dimension, and were collected preoperatively and one year after THA.

RESULTS: The gluteal tendons were graded as 4 distinct grades: normal (n = 1,023, 66%), tendinopathy but no tear (n = 337, 22%), partial thickness tear (n = 131, 9%), and full thickness tear (n = 47, 3%). The occurrence of GT was associated with age, body mass index, and sex. There was no significant difference in baseline OHS or HOOS JR scores according to GT grade. As GT grade increased, lower median 1-year OHS (P = .001) and HOOS JR (P = .016) were observed. This association was confirmed by linear regression analysis with 1-year OHS (B = 0.5, 95% CI = -0.9 to -0.1, P = .011) when controlled for age and sex.

CONCLUSIONS: Gluteal tendinopathy was commonly observed and was associated with inferior 1-year PROMs in patients undergoing THA via posterior approach. Increasing degree of tendinopathy was a negative prognostic factor for outcomes and patient satisfaction.

LEVEL OF EVIDENCE: Level 2 (High quality prospective cohort study).