Ballet dancers often report a snapping sound or sensation in the hip. It may or may not be painful. In this study, real-time ultrasound (US) is used to identify the cause of the snapping. Dancers were also examined by a doctor and a physical therapist.
Real-time ultrasound allows the tendon to be examined as it moves across the hip joint. Abnormal or jerky movements of the iliopsoas tendon and iliotibial band (ITB) were of special interest. The iliopsoas muscle and tendon help flex or bend the hip. The ITB is a band of connective tissue that goes from the hip to the knee along the outside of the thigh.
Twenty-six (26) dancers from a professional ballet company and school were included. Most of the dancers had symptoms of snapping hip on both sides. Half reported the snapping started when they were 14 to 16 years old. Many could make the hip snap on purpose. Some dancers snap the hip to make the pain go away. For others, snapping is a habit.
US results showed that the iliopsoas tendon moving over the bone caused the snapping in almost two-thirds of the cases. Sometimes the tendon rolled over the bone and got stuck in the muscle. Only a small number of dancers (four per cent) had a snapping ITB. US was unable to identify the cause in the remaining one-third of the dancers.
Examiners were unable to identify the exact cause of the snap without an US. Even with US, it’s not clear if later hip problems develop because of the snapping. Dancers do not seem disabled by this problem as much as it is annoying.
Future studies are needed to follow dancers for years to see what happens naturally. It may be possible to identify dancers at risk for snapping hip syndrome and prevent it. This is especially important if it turns out that any amount of disability occurs as a long-term result of snapping hip.