Femoroacetabular impingement (FAI) syndrome is the clinical symptoms and signs of painful, limited hip motion resulting from certain types of underlying morphological abnormalities in the femoral head-neck region and/or acetabulum. Femoroacetabular impingement can lead to early degenerative disease.

A common cause of early degenerative changes in the hips of young adults

Pathology

An intra-articular impingement where structural changes and repetetive abnormal contact of the actebulum and femoral head lead to mechanical stress and shear forces on the labrum and chondral surfaces = subsequent damage

2 types:

• Cam type - excess bone on upper femoral head (Loss of sphrecity) leading to sheer forces and damage to the acetabular labrum
• Pincer type - Focal or global actebular over-coverage = leads to labral compression and chondral wear at the site of the impingement
• Mixed type - a combination of the two

PC

• Motion or position related hip and/or groin pain
• Sometimes the pain is also described in the buttock, back or thigh
• there may be symptoms of stiffness, clicking, locking, catching

Investigations

1st line - Pelvis x-ray

CT/MRI - advised for better characterisation, the detection of chondral and labral lesions and preoperative planning

Management