Prevalence of Gluteus Medius Pathology on Magnetic Resonance Imaging in Patients Undergoing Hip Arthroscopy for Femoroacetabular Impingement: Asymptomatic Tears Are Rare, Whereas Tendinosis Is Common

Abstract

Background: There is a paucity of literature on asymptomatic gluteus medius pathology. Moreover, no studies have examined the prevalence of asymptomatic gluteus medius pathology. Purpose: To describe the prevalence of asymptomatic gluteus medius pathology in patients undergoing hip arthroscopy for femoroacetabular impingement. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A database search of our institution was performed for patients undergoing hip arthroscopy for labral treatment between February 2008 and January 2019. Patients were included if they had gluteus medius pathology identified through magnetic resonance imaging (MRI). Patients were deemed to be asymptomatic if they lacked greater trochanteric hip tenderness, abductor weakness, a positive Trendelenburg sign, or a positive Trendelenburg gait on physical examination. Patients were excluded if they were unwilling to participate or did not have a documented physical examination or MRI read in the database. Results: A total of 2851 hips (2452 patients) met the inclusion/exclusion criteria. Gluteus medius pathology was found in 871 hips (30.6%) on MRI. Symptomatic gluteus medius pathology was observed in 414 (14.5%) hips, of which 305 (10.7%) had tendinosis, 99 (3.5%) had partial-thickness tears, and 10 (0.4%) had full-thickness tears. Asymptomatic gluteus medius pathology was observed in 457 (16.0%) hips, of which 408 (14.3%) had tendinosis and 49 (1.7%) had partial-thickness tears. No hips with full-thickness tears on MRI were asymptomatic. Patients with asymptomatic partial-thickness tears were significantly older than those with only tendinosis (45.3 vs 39.4 years, respectively; P = .001). Patients aged 40 years or older had a 2.11 (1.80-2.50) (P < .001) relative risk of asymptomatic pathology compared with patients younger than 40 years. Conclusion: Although there is a meaningful prevalence of asymptomatic gluteus medius tendinosis, the prevalence of asymptomatic gluteus medius tears is low. Treatment of gluteus medius tendinosis should therefore be based not solely on MRI findings but rather on a complete clinical evaluation. In contrast, MRI findings of partial or full-thickness gluteus medius tears may be more likely to have clinical significance.