It is characterized by pain that is often felt in the groin area, which is made worse when the hip is placed into a position of flexion (knees toward the chest). Less frequently, pain is felt deep in the buttock and pain is produced with movements that involve hip abduction (leg out sideways) and external rotation (thigh turned outward).
The shape of your hip joints is a key determinant for impingement. Think of the hip joint as a ball and socket. Problems with the shape of either part can cause impingement.
CAM Deformity: This is a bony bump located at the junction between the femoral head (ball) and neck of your femur, making the “ball” of the hip joint less round. This bump comes into contact with the acetabulum (cup) with flexion movements of the hip.
Pincer deformity: This is when the cup side of the joint covers too much of the femoral head (ball). If the cup is too deep, it can collide with the femur during movements that are near the end of a person’s available hip range of motion.
These collisions can result in tearing of the acetabular labrum (this is the cartilage pad that lines the cup side of the joint) and painful bony bruising.
Why do some people have these deformities and no pain?
Impingement only occurs when a person’s activity requires a range of motion that their joint cannot provide. Two patients with the same joint shape may have very different experiences if one is a swimmer and the other is a mogul skier. The mogul skier’s choice of sport requires extremes of hip flexion under powerful force so they will be more likely to experience impingement.
It is important to find a physiotherapist who fully understands this condition and can design an exercise program specific to your condition. Physiotherapy for femoro-acetabular impingement (FAI) should be focused on developing excellent strength, endurance and motor control of the hip joint, pelvis and lumbar spine. The goal of physiotherapy is not to increase joint range of motion (attempts at this usually result in more impingement). A large percentage of patients who suffer from impingement can manage their problem with exercise and some education on what types of things will make their hip pain worse.
Arthroscopic surgeries have been developed to address impingement for patients where physiotherapy has not been successful. These surgeries involve placing the hip under traction and using small instruments inside the joint to reduce or eliminate the impingement. Surgeons will commonly remove the CAM deformity from the femur, remove some bone from the acetabular rim and/or repair the acetabular labrum. For further information on hip arthroscopy, an excellent resource is:
At Cornerstone Physiotherapy in Toronto, we have been instrumental in developing physiotherapy protocols for the local surgical community to treat people with femoro-acetabular impingement. These protocols have been adopted to help patients try to avoid surgery, as well as to ensure complete rehabilitation following an arthroscopic procedure. Please contact us for more details.