Femoroacetabular Impingement: symptoms, treatment and recovery

This condition can occur in up to 25% of the population, but the exact rate is unknown due to asymptomatic cases, and when left untreated, FAI can lead to cartilage damage, pain, limited mobility and hip osteoarthritis. Femoroacetabular Impingement significantly jeopardises quality of life. Find out what it is and how it’s treated.

Femoroacetabular Impingement: what is it?

Femoroacetabular Impingement is a condition that affects the hip joint. FAI is characterised by abnormal contact between the femoral head (thigh bone) and the acetabulum (part of the pelvic bone that forms the hip socket). This friction places greater pressure on certain parts of cartilage, thereby wearing down the joint. At worst, it can cause hip osteoarthritis.

What causes Femoroacetabular Impingement?

Femoroacetabular Impingement has various causes, but the condition is usually associated with anatomical changes in the hip joint. These changes can occur during development or are acquired throughout life. The principal causes include:

Bone deformities

In most cases, the cause of Femoroacetabular Impingement is unknown. Both the femoral head and the acetabulum can present an abnormal shape or excessive bone growth (“bone spur”), although in 85% of cases, it is a combination of causes.

Ligamentous laxity

Ligamentous laxity is a clinical condition in which the ligaments that support joints are more flexible than normal, causing joints to have an excessive range of motion. This situation can lead to abnormal contact between joints, causing Femoroacetabular Impingement.

Prior injuries or traumas

Prior injuries, like hip fractures, dislocations or traumas, can cause structural alterations in the joint and lead to the development of Femoroacetabular Impingement.

How is Femoroacetabular Impingement diagnosed?

The diagnosis of Femoroacetabular Impingement is performed by an Orthopaedic surgeon and usually involves the following steps:

Clinical history and medical examination

The physician will ask questions about the symptoms, medical history and prior injuries. During the medical examination, the specialist checks for decreased joint mobility and pain caused by movements that involve flexion/extension, internal/external rotation, and abduction/adduction of the hip joint.

Imaging exams

X-rays are often prescribed as an initial imaging examination, as these can reveal changes in bone structures, such as an abnormal femoral head, osteophytes (bones spurs) or pincer morphology. Magnetic resonance imaging (MRI) is the gold standard for diagnosis. This test characterises bone deformities and evaluates soft tissues, namely the acetabular labrum and hip joint cartilage. CT scanning is rarely needed, but may be useful to provide a differential diagnosis or characterise bone structures.