Labral tear
A hip labral tear involves damage to a fibrous rim of cartilage surrounding the hip socket that is important in providing stability to the hip joint by keeping the head of the thigh bone (femur) inside the hip socket (acetabulum).
By interconnecting with the joint capsule, the labrum also helps seal the hip joint, maintaining fluid pressure inside the joint and nutrition to the joint cartilage.
Many hip labral tears cause no signs or symptoms. Occasionally, though, one or more of the following may be experienced:
- pain in your hip or groin, which may also be experienced down the front of the thigh all the way down to the knee, in the buttocks and/or on the outer aspect of the hip;
- limping;
- a locking, snapping, clicking or catching sensation in your hip joint;
- joint stiffness, instability or limited range of motion in your hip joint.
Symptoms often get worse with long periods of standing, sitting, or walking. The pain can be constant and severe enough to limit all recreational and sports participation. It is not known whether a hip labral tear predisposes to the development of osteoarthritis in that joint in the future.
It was once believed that a single injury was the main cause of labral tears. But a number of recent studies clearly show that abnormal shape of the hip joint is a leading cause. This can be a result of childhood conditions, such as congenital hip dysplasia and Perthes’ disease, but such changes usually occur gradually over time, often without symptoms, which predispose it to tearing under “normal” circumstances when the joint is placed under extra load such as such running, twisting or slipping.
The most common of such underlying conditions is called femoral acetabular impingement (FAI). With FAI, there is reduced joint space between the thigh bone (femoral) head and neck and the acetabular rim. The upper end of the thigh bone butts up against and compresses the rim when the thigh is bent up (flexed) and turned inward (internally rotated). Maintaining this position for prolonged periods of time may eventually lead to a deterioration of the cartilage, fraying, tearing and possibly a complete separation of the cartilage (avulsion) from the cup of the hip (acetabulum).
Prevention and treatment of labral tears is based on an understanding of the primary role of mechanical forces acting on the hip.
Your hip joint is surrounded and acted upon by seventeen muscles, many of which are the most powerful muscles in your body. Of all these muscles, biomechanical studies have found that three muscles are most important for stabilising your hip - your gluteal, tensor fascia latae and hip flexor muscles. At the same time these muscles place the most load on your hip joint.
When these muscles are used in balance with other muscles, the forces acting on the hip joint are evenly spread out over the largest possible area with each bit sharing the load. But many people have a propensity to unnecessarily overwork one or more of these muscles, leading to a relatively small area at the upper front of the hip joint, the area most commonly and severely affected by labral tears, taking on the brunt of the load. At the same time other parts of the joint tend to become under-loaded, which can also lead to weakening and breaking down of cartilage.