Femoroacetabular impingement (FAI) syndrome is a recently recognized diagnosis in primarily younger individuals where relatively minor abnormalities in the joint (orientation or morphology) are thought to cause friction/impingement and pain. It is theorized that FAI starts the breakdown of cartilage, leading to osteoarthritis (OA). There are two types of FAI: cam impingement (most common in young athletic males) and pincer impingement (most common in middle-aged women).
Proponents believe that surgical correction of the impinging deformities will alleviate the symptoms and retard the progression of OA degeneration. However, significant questions remain about the safety, efficacy and effectiveness, and cost effectiveness of hip surgery for FAI.
Primary criteria ranking:
- Safety = Medium
- Efficacy = High
- Cost = High
- Documents (all assessments)
Update literature (2018)
Update literature (2014)
Assessment timeline (2019)
- Draft key questions published: May 28, 2019
- Public comment period: May 28 to June 11, 2019
- Final key questions published: June 19, 2019
- Draft report published: September 5, 2019
- Public comment period: September 5 to October 4, 2019
- Final report published: October 23, 2019
- HTCC public meeting: November 22, 2019
Femoroacetabular impingement (FAI) results from abnormal morphology of the acetabulum and femoral head/neck resulting in abnormal contact between the proximal femur and acetabulum during the end range of hip motion, particularly flexion and internal rotation. There are two types of FAI: cam impingement (non-spherical femoral head or abnormality at the head-neck junction) and pincer impingement (deep or retroverted acetabulum resulting in overcoverage of the femoral head). Clinically, patients frequently present with a combination of both types. Morphologic characteristics of FAI and labral tears on radiographs in asymptomatic patients appear to be common. Abnormal contact between the femur and acetabulum may result in impingement and pain and/or reduced function; this may depend on activity level. Repetitive motion, particularly vigorous motion may result in joint and labral damage. A recent consensus document has suggested that the term femoroacetabular impingement syndrome (FAIS) be used for symptomatic presentation of FAI. There is mixed evidence linking FAI to later development of osteoarthritis (OA); some studies suggest that cam lesions may be linked to OA development, but the impact of pincer lesions is less clear. One recent study reported no difference in the risk of OA progression between patients with FAI and those with normal hip morphology.
Initial management of FAI/FAIS usually is nonoperative. Surgical options to correct FAI include arthroscopy, open dislocation of the hip and arthroscopy combined with a mini-open approach. The purpose of the surgery is to remove abnormal outgrowths of bone and damaged cartilage, and to reshape the femoral neck to ensure that there is sufficient clearance between the rim of the acetabulum and the neck of the femur.