Femoral Acetabular impingement syndrome
Femoral acetabular impingement occurs when there is a decreased joint clearance between the femur and the acetabulum. There are two different types of FAI, known as cam and pincer.
- Cam occurs when the femoral head is aspherical and has an abnormally large radius. This causes abnormal contact between the femur and and the acetabulum, especially with the combined movements of flexion, adduction and internal rotation of the hip. This type of impingement is associated with anteriosuperior labral and chondral lesions. Cam impingements are more common in young male athletes.
- Pincer impingement occurs when the acetabulum has too large a coverage of the femoral head, resulting in a pinching of the labral cartilage at the top rim of the socket. This coverage can be general or local anterior, which is caused by acetabular retroversion. Typically, pincer impingements are more common in middle-aged women participating in sports.
Signs and symptoms
- Anterolateral hip pain is most common (C-sign = patient will cup hand over anterolateral aspect of the hip)
- Some patients with FAI complain of low back pain that is localized to the back of the pelvis at the sacroiliac joint, the buttock, or greater trochanter.
- Pain that is sharp when turning or pivoting, especially to the affected side
- Pain that is worse with prolonged sitting, rising from a seat, getting into or out of a car, or leaning forward
- Pain is gradual and progressive
Special tests
- FADIR TEST- Flexion, adduction, internal rotation
- Most sensitive physical examination test for FAI
- Reproduction of the patient's anterolateral hip pain is consistent with FAI
Treatment
- No published studies of conservative treatment of FAI
- Treatment goals include improving hip muscle flexibility and strength, posture and other muscle or joint deficits identified in the physical exam
- Patients with stubborn cases of FAI should be referred to an orthopaedic subspecialist for consideration of arthroscopy
References
Dutton M. Orthopaedic Examination, Evaluation, and Intervention. 2 ed: McGraw-Hill, Medical Publishing Division; 2008.http://www.hipfai.com/
Kuhlman GS, Domb BG. Hip impingement: identifying and treating a common cause of hip pain. Am Fam Physician. 2009;80(12):1429-1434.
Images
http://www.jointpain.md/Procedures/ImpingementSyndrome.aspx
http://www.eorthopod.com/images/ContentImages/hip/femoroacetabulr_impingement/hip_FAI_intro01.jpg
Kuhlman GS, Domb BG. Hip impingement: identifying and treating a common cause of hip pain. Am Fam Physician. 2009;80(12):1429-1434.
Images
http://www.jointpain.md/Procedures/ImpingementSyndrome.aspx
http://www.eorthopod.com/images/ContentImages/hip/femoroacetabulr_impingement/hip_FAI_intro01.jpg