Femoro-acetabular impingement

Femoro-acetabular impingement (FAI) is a condition of the hip joint that is characterised by abnormal contact between head of the femur (ball) and the acetabulum (socket). FAI can be subgrouped into Cam or Pincer deformities. A cam deformitiy is where extra bone forms around the head of the femur resulting in a bone ‘bump’, this results in the femoral head having an aspherical appearance. A pincer deformity is where bone forms around the edges of the socket or acetabulum and results in over-coverage of the femoral head. It is possible to have mixed pathology, where both cam and pincer deformities co-exist.

Taken from www.jointpain.md 25/5/15


The evidence from the literature suggests that cam deformities develop in adolescents that are involved in sports that are subject to high rotational forces across the hip such as AFL football and soccer. Cam deformities can lead to an increased risk of osteoarthritis in later life whereas pincer deformities do not.

Common symptoms associated with FAI include; hip and groin pain, there may be referred pain into the anterior thigh or knee. Pain is often provoked with sitting in a low chair, crossing the legs in sitting or activities that involve twisting the hip such as getting in and out of the car and twisting on a stationary foot. Patients with FAI often report restricted movement with hip flexion (bending the hip) and internal rotation (twisting the hip inwards).

Sports such as soccer, AFL and tennis are often associated with FAI as they involve high levels pivoting and twisting forces.

A  clinical diagnosis of FAI is made with a positive impingement test which is called the FADIR test – hip flexion/internal rotation/hip adduction. The test is considered positive with pain reproduction and restriction in movement.

FAI is confirmed with plain x-rays which identifies the deformity. If a labral tear is suspected an MRI may be warranted. In complex cases a 3D CT scan may be ordered by an orthopaedic surgeon to further assess joint integrity.

Physiotherapy is based on correcting biomechanical factors, strengthening the deep hip external rotators, releasing any tight muscles, re-training pelvic control and prescription of mobility exercises to promote range of motion.

Some cases may require orthopaedic surgery. This consists of a hip arthroscope where the bone ‘bump’ is removed by a bone shaver. This results in pressure being alleviated from the socket and often relieves pain and improves function.

All physica staff receive extra training in the diagnosis and management of FAI. We will conduct a thorough assessment and devise an appropriate course of action including referral for specific radiology and this may include referral to specialists for surgical opinions.