Posterior-Anterior Glide of the Femoral Head in the Acetabulum: A Cadaver Study

STUDY DESIGN: Descriptive study employing cadaver dissection and measurement of posterior-anterior (PA) glide of the femoral head in the acetabulum. OBJECTIVE: To quantify PA glide of the femoral head in the acetabulum in a cadaveric sample. BACKGROUND: Posterior-anterior glide of the femoral head within the acetabulum is a joint mobilization procedure described in orthopaedic physical therapy texts, yet there is no published evidence that the joint structures of the hip allow such movement. This study attempted to quantify PA glide of the femoral head in the hip joints of embalmed cadavers. METHODS: Twelve hips, 3 male and 9 female, from 8 embalmed cadavers were employed in this study. Hips were dissected to the level of the joint capsule and a metal rod inserted through the femoral neck served as a mobilizing handle. A load cell was installed into this handle so that mobilizing forces could be monitored. A dial gauge, which recorded displacement of the femoral head, was mounted to the pelvis via bone pins and an external fixator. RESULTS: Using mobilizing forces of 89, 178, 267, and 356 N, mean femoral head displacements of 0.57, 0.93, 1.20, and 1.52 mm were recorded. Within the 89-N trials, PA displacement ranged from a minimum of 0.04 mm to a maximum of 1.54 mm. Within the 356-N trials, PA displacement of the femoral head ranged from a minimum of 0.25 mm to a maximum of 2.90 mm. CONCLUSION: In an embalmed cadaveric model, measurable PA glide of the femoral head within the acetabulum does exist and it is highly variable between individuals.