[Femoro-acetabular impingement: a cause of groin pain and early hip osteoarthritis in younger patients].

In Denmark, approximately 7,000 hip joints are replaced by total hip arthroplasties annually. In 80% of the cases, the diagnosis is idiopathic end-stage osteoarthritis. Scientifically this is hardly acceptable. However, the last decade has witnessed a proliferative research in biomechanically important, often subtle, malformations of the hip joint which are thought to play an important role pathogenetically for the development of hip osteoarthritis and hip pain especially in younger, active patients. The common denominator for these malformations is that they cause femoro-acetabular impingement during hip flexion and internal rotation. Repetitive microtrauma damages the acetabular labrum and cartilage, and the osteoarthritic cascade is initiated in earnest. This review evaluates new research relating to this paradigm.