Snapping hip a very common complaint in runners, dancers and athletes with repetitious use of their hips. Most people only feel or hear an unpainful snap, in which case, there is nothing to worry about. However, pain and/or weakness may be a sign of a true problem. Some sort of painless hip snapping happens in about 5-10% of people. Many times a physician will need to be consulted to help determine the cause of the snapping. An exam will be done and hopefully reproduction of the snapping will lead to the diagnosis. Many times externally rotating and abducting the leg will reproduce a snap. An xray may be done to look at the hip joint and determine if there is a bony loose body in the joint. For some conditions an MRI with dye (arthrogram) may be necessary. Ultrasound has become a mainstay in diagnosing snapping hip and can be used in the office to visualize tendons while the hip is in motion.
There are two areas that can cause the snapping sensation: Intraarticular (within the hip joint and extra articular (outside the joint), which can be either laterally (on the outside portion of the hip) or medially (the inner portion.)
Intra articular pain comes from within the hip joint, a ball and socket joint surrounded by a capsule. There are several reasons that structures within the hip joint could cause snapping. The most likely reason is a labral tear. The acetabulum (socket) is lined with a fibrocartilaginous layer called the labrum, which adds stability. The labrum can become torn with trauma or repetitive motions. Patients will feel pain deep within the groin and it can be hard to localize. A torn labrum cannot heal. Many will find relief with physical therapy aimed at strengthening hip flexors and mobility of the hip. Injection of steroid into the hip joint can help to decrease inflammation. If conservative measures do not help, arthroscopic surgery may be recommended, unless arthritis is present. Another reason for snapping within the joint can be a loose body, such as a piece of cartilage or a fragment from a fracture. If this is the case, arthroscopic surgery may be needed to remove the object. Damage to the cartilage can also cause snapping within the hip joint and can be caused by overuse or arthritis.
Outside the joint, there can be two areas causing snapping. Internal snapping is usually caused by movement of the iliopsoas tendon or muscle over the iliopsoas bursa, joint capsule or pelvic brim. The iliopsoas is made of two muscles, the psoas and the iliacus. The snapping may be visualized by ultrasound, which allows the athlete to make the motion reproducing the snap while the muscle and tendon are visualized. Physical therapy designed to strengthen the muscles and stretch the iliopsoas may be helpful. A steroid injection can be made into the iliopsoas bursa, if it is enlarged.
External snapping is felt on the outside of the hip and can be caused by a few issues. The upper end of the IT band, the tensor fascia lata, may be inflamed and snap over the greater trochanter of the femur. The pain would be felt at the side of the hip instead of the front. The gluteus maximus also passes over this area to insert of the greater trochanter and may be responsible for snapping. There is a bursa over the trochanter which may be enlarged. This area can be visualized with ultrasound and the responsible structure may respond to a steroid injection or physical therapy to stretch the IT band. Although there are some surgical techniques for an external snapping hip, the vast majority do not require surgery.
Overall, snapping hip is really only a problem if it causes pain or weakness. Determining the source of the snapping can be more complicated than it would first seem. Getting a physician involved if it is symptomatic is very important.
