Hip impingement: recognizing, understanding and treating a common cause of hip pain
A great deal of progress has been made in recent years in diagnosing and treating nonarthritic hip injuries and disorders. Femoroacetabular impingement (FAI), or hip impingement, has become increasingly identified as one of the more common causes of hip pain in athletes, adolescents and adults.
As a ball-and-socket joint, the hip contains a cup-shaped depression called the acetabulum (socket), which is connected to the thighbone, or femur (ball), with a protective lining of articular cartilage. Articular cartilage is the shock absorber which lines bone in joints. FAI is due to the rim of the acetabulum rubbing against the femur. The result of this rubbing, or impingement, is injury to the cartilage on the rim of the socket and the articular cartilage of the femur bone. This cartilage on the rim of the socket is called the labrum (another cushioning cartilage structure).
The above scenario can lead to osteoarthritis if left untreated. It usually occurs while flexing or rotating the hip, and some of the common activities that can make it worse are prolonged sitting, leaning forward and getting in or out of cars. The condition typically progresses gradually, beginning either in adolescence or adulthood, and the resulting pain can be extremely debilitating in both exercise and daily life activities. Although many cases of FAI are found in people with bony abnormalities that can be genetic or developed later in life, some occur in healthy hips. Activity, trauma and sports can play a role in development of this condition as well.
Patients with FAI will usually experience pain in the front of the hip and towards the side. When reporting the pain to physicians, they'll oftentimes cup the area and report increased pain when turning, pivoting or while engaging in any of the harmful activities mentioned above. If patients complain of pain, physicians should proceed with a physical examination and an FADIR test, which measures elements of the hip's flexibility and range of motion. From there, if symptoms and the physical examination both point towards FAI, X-rays are taken to assist with the diagnosis. X-ray results concurrent with FAI indications lead to the next and usually final step in determining FAI, an MRI arthrogram. The procedure is essentially a regular MRI but with a liquid contrast material injected into the joint to get a better read on how it's functioning. The liquid contrast material is followed by an injection of local anesthetic, which, if it reduces pain, will confirm the location of the pain as intra-articular, and therefore an FAI. MRI arthrograms have much better sensitivity than ordinary MRIs and are extremely effective in confirming FAI.
Presently, studies are lacking regarding the effectiveness of non-surgical treatment of FAI; however, physical therapy is an option often recommended. Physical therapy sessions should feature of goals that improve hip muscle flexibility and strength, posture and other muscle or joint deficits. If patients' problems are still unresponsive to these treatments, they should be referred to an orthopedic specialist for consideration of arthroscopy, a minimally invasive surgical procedure. A number of case series studies
have shown arthroscopy to create predominantly favorable outcomes in patients with FAI, though osteoarthritis of the hip typically reduces the likelihood of this result.
-As reported in the Dec. 15, 2009 edition of American Family Physician
-Summarized by Greg Gargiulo
