Anatomy and Dimensions of the Gluteus Medius Tendon Insertion

Purpose: The purpose of this study was to determine the area, dimensions, and orientation of the gluteus medius footprint to provide an improved understanding of its insertional anatomy. Methods: Eight fresh-frozen cadaveric hips were dissected, leaving only the most distal gluteus medius tendon attached to the greater trochanter. The tendon insertion footprint and proximal femur were digitized and mapped by use of 3-dimensional computer navigation software. The area, location, and dimensions of the tendon insertion were determined. Results: The gluteus medius tendon has 2 distinct insertion sites on the greater trochanter, the lateral facet and the superoposterior facet. The mean areas of insertion onto the lateral and superoposterior facets were 438.0 mm² (SD, 57.7 mm²) and 196.5 mm² (SD, 48.4 mm²), respectively. The lateral facet footprint had a mean longitudinal dimension of 34.8 mm (SD, 4.3 mm), was angled at a mean of 36.8° (SD, 6.7°) relative to the long axis of the femur, and had a mean minimum width of 11.2 mm (SD, 1.8 mm). The superoposterior facet's shape approximated that of a circle, with a mean diameter of 17 mm (SD, 2.0 mm). Conclusions: The gluteus medius tendon has 2 distinct and consistent insertion sites onto the greater trochanter. This information will provide surgeons with a better understanding of the footprint anatomy when evaluating gluteus medius tendon tears. Clinical Relevance: Gluteus medius tendon tears can be a source of significant pain and morbidity. This study describes the anatomic morphology of this tendon insertion, which should aid in its repair when necessary.