Gluteus minimus tendinopathy and total hip arthroplasty through direct anterior approach: incidence, associated factors, and treatment results

Gluteus minimus (GMin) tendon pathology is underreported and probably one of the most frequent causes of lateral hip pain. Today, direct anterior approach (DAA) for total hip arthroplasty (THA) is one of the most used approaches. DAA is the only surgical approach that allows a very good visualization of GMin tendon without the need for any other tendon detachment. This study first aimed to determine the real incidence of intraoperatively detected GMin lesions in a consecutive cohort of patients during their THA through a DAA. Furthermore, factors associated with these lesions have been analyzed as early treatment results. A consecutive cohort of 123 patients who underwent primary THA through the DAA at a single surgeon was intraoperatively screened for GMin tendinopathy. In case of a GMin tendon lesion, tendon to bone sutures and/or a tenodesis GMin-vastus lateralis or, rarely, anchor suture, were performed. The iHOT-12, modified Harris Hip Score (mHHS), Numeric Rating Scale (NRS) for pain, and VISA-G were recorded at baseline (T0), 2 months (T2), and 6 months (T6) postoperatively. Longitudinal changes were analyzed with one-way repeated-measures analysis of variance (ANOVA) and post-hoc pairwise comparisons. Patients were stratified by intraoperative GMin lesion status; group differences up to 6 months were assessed with unpaired t -tests, and multivariable logistic regression was used to identify baseline factors associated with GMin lesions. Intraoperative GMin tendon lesions were identified in 24 (19%) of the 123 patients and in 44% of the sub-group of women older than 75 years. Older age (OR 1.06 per year, 95% CI 1.02–1.11; p = 0.002), female sex (OR 6.25, 95% CI 2.18–16.03; p = 0.0004), and higher ASA grade (OR 2.50, 95% CI 1.33–4.76; p = 0.004) were associated with higher odds of a GMin lesion. BMI showed a nonsignificant association ( p = 0.056) and smoking was not associated ( p = 0.830). All patient-reported outcome measures (PROMs) improved significantly at 6 months (all p < 0.0001). The 6-month improvement did not differ significantly between patients with or without GMin lesions for the iHOT-12 ( p = 0.626), HHS ( p = 0.542), NRS ( p = 0.184), or VISA-G ( p = 0.529). GMin tendon lesions are easily and commonly seen during DAA though THA, particularly among elderly women. In our small series, concomitant repair was associated with PROMs comparable to those of patients without GMin lesions. These exploratory findings must be confirmed by prospective multicenter studies with longer follow-up, but they already suggest an intraoperative vigilance for GMin tendon lesions, especially warranted in at-risk patients.