Abstract
For diagnosis of FAI (femoroacetabular impingement), it is useful to obtain not only a static image but also a dynamic image, as FAI is affected by dynamic factors in the hip joint. We assessed the usefulness of ROM (range of motion) simulation using 3D CT for diagnosis of FAI in a 34-year-old man with thigh pain and a decreased range of hip joint motion. He had a history of fracture of the femoral shaft. Plain X-ray demonstrated the pistol grip deformity and the formation of a bump at the anterior head-neck junction. ROM simulation using 3D CT revealed that impingement occurred between the femur and the edge of the acetabulum at 65 degrees of hip flexion, compared with 100 degrees in the contralateral hip joint. We carried out surgical dislocation and resected the bone spur at the edge of the acetabulum and the bump at the anterior head-neck junction, and performed osteochondroplasty. Postoperatively, the patient was relieved of thigh pain and achieved a wide range of hip motion. ROM simulation showed impingement at 90 degrees of hip flexion. ROM simulation using 3D CT is useful for diagnosis of FAI and treatment planning.
