Femoroacetabular

Femoroacetabular describes structures and processes related to the hip joint formed where the femoral head meets the acetabulum of the pelvis. The term is used in anatomy and medicine to refer to conditions affecting this joint, most notably femoroacetabular impingement.

Femoroacetabular impingement (FAI) is a common focal disorder of the hip caused by abnormal contact between the femoral head-neck region and the acetabular rim during hip motion. This repetitive impingement can lead to damage of the acetabular labrum and the articular cartilage, with symptoms typically including groin pain and stiffness, especially with hip flexion, internal rotation, or after activity.

There are three general patterns of FAI: cam type, where the femoral head is not perfectly round and clashes with the acetabulum; pincer type, where excess acetabular coverage causes impingement; and mixed type, featuring both elements. Individual anatomy and repetitive motion contribute to the development of these morphologies.

Diagnosis is based on clinical history and physical examination, supported by imaging. X-rays in several views assess bone morphology, while MRI or MR arthrography evaluates soft tissue damage such as labral tears. Specialized views, like the Dunn view, can help identify cam deformities.

Treatment begins with nonoperative approaches, including activity modification, physical therapy, and NSAIDs. When these measures fail or there is persistent structural pathology, surgery may be considered. Hip arthroscopy aims to reshape the femoral head-neck junction (femoroplasty), decompress the acetabular rim, and repair or debride the labrum. Open surgical dislocation is used in select cases.

Prognosis improves with timely, appropriate management, but untreated FAI can contribute to progressive joint degeneration and osteoarthritis.