Snapping hip syndrome is one condition that is being studied in the new field of dance medicine. Dance medicine is a relatively new branch of sports medicine focusing on the unique physiological demands of dancers and how to best prevent and treat their specific injuries.
Anatomy of the Hip Joint
Although the hip is considered a stable joint, the unique demands in dance for extreme hip flexibility can create a condition within the hip that causes snapping of the soft tissue structures over the bony structures.
The hip is a “ ball and socket” joint in which the head of the femur (ball) sits deep within the acetabulum (socket) of the pelvis. The acetabulum creates a deep pocket for the head of the femur to sit in. This bony structure creates a stable joint, but the stability is also enhanced by soft tissue structures including the labrum (dense fibrocartilaginous tissue that surrounds the acetabulum to further deepen the pocket) and three strong ligaments (ischiofemoral, pubofemoral, iliofemoral).
The purpose of these ligaments is to support the hip joint by providing additional structures to limit motion. Ligaments connect bone to bone. Although ligaments do have some elastic properties (they are able to stretch and return to original shape to some extent), they are structurally designed to limit motion at a joint.
The hip joint has numerous muscles that are layered from deep to superficial. These muscles provide the movement for the hip joint including flexion, extension, abduction (out to the side), adduction (opposite of abduction), internal (turning in) and external rotation (turning out).
Causes of Snapping Hip Syndrome
There are a number of possible causes for snapping hip syndrome. They can either be caused by structures inside the joint (intra-articular) or outside of the joint (extra-articular). Although there are a number of structural possibilities, the literature focuses on two primary causes. Both are caused by a muscle or tendon “popping” over a bony structure.
According to information published by the Harkness Center for Dance Injuries, there are two kinds of snapping hip that frequently occur in dancers. The most common form is lateral snapping hip (snapping on the side of the hip) caused by the iliotibial band (dense connective tissue that runs down the side of the leg) snapping over the greater trochanter (large bony prominence) of the femur.
The second type of snapping hip occurs in the front of the hip and may be caused by a deep hip flexor muscle/tendon (iliopsoas) popping over a bony prominence of the pelvis. Other causes may include (Anderson, M.K., Parr, G.P., & Hall, S.J., 2009):
- Snapping of the long head of the biceps femoris muscle over the ischial tuberosity
- Snapping of the iliofemoral ligament over the femoral head
- Iliotibial band friction syndrome
Treatment of Snapping Hip Syndrome
There is no need for treatment if there is no pain associated with a snapping hip. Dr. Lyle J. Michell, Director of the Division of Sports Medicine at Children’s Hospital and Associate Clinical Professor of Orthopaedic Surgery at Harvard Medical School, recommends “early intervention before the condition develops into full-blown tendinitis” (Dance Medicine, Harvard Orthopedic Journal). Early treatment includes:
- Correct errors in technique/alignment
- Increase flexibility of the iliopsoas
- Increase flexibility of the external rotators of the hip
- Strengthen the muscles of adduction, internal and external rotation
In a study of advanced snapping hip syndrome, females treated with corticosteroid injection of the iliopsoas tendon sheath showed promising results (Dr. L.Michell, Harvard Orthopedic Journal).
In cases where there is pain or a feeling of instability within the hip, the dancer needs to be referred to a physician for proper diagnosis, treatment, and rehabilitation program.
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