Identification and differentiation of gluteus medius tendon pathology using ultrasound and magnetic resonance imaging

Abstract Background It has been suggested that imaging findings play a role in directing treatment for Greater Trochanteric Pain Syndrome. Structural diagnoses associated with Greater Trochanter Pain Syndrome include gluteal tendinosis, and partial- or full-thickness gluteal tendon tears. However, few studies have compared imaging to confirmed tendon pathology observed during surgery. Objective To investigate the ability of magnetic resonance and ultrasound imaging to identify the presence of a pathological gluteus medius tendon in comparison to surgical and histological findings. Study design Cross-sectional study. Methods 26 participants undergoing gluteal tendon reconstruction surgery or hip arthroplasty were included. Prior to surgery, participants underwent both magnetic resonance (MR) (n = 23) and ultrasound (US) (n = 25) imaging. A radiologist (MR) and nuclear physicians (US) classified the gluteus medius tendon as normal, tendinosis (no tear), partial-thickness tear, or full-thickness tear. Results Ultrasound identified 17 out of the 19 pathological gluteus medius tendons correctly. However, 5 of the 6 normal tendons were incorrectly identified as exhibiting pathology on ultrasound. Magnetic resonance rated 11 out of 17 pathological tendons as abnormal, with 4 out of 6 normal tendons identified correctly. Both imaging modalities were poor at identifying and differentiating between tendinosis and partial-thickness tears. Conclusion Both imaging modalities showed a reasonable ability to identify tendon pathology. While limited by sample size, these early findings suggest that both imaging modalities may be limited in identifying specific pathoanatomical diagnoses, such as partial-thickness tears. These limitations may misdirect treatment.