Femoroacetabular Impingement, or hip impingement syndrome, may affect the hip joint in young
and middle-aged adults and occurs when the ball shaped femoral head rubs abnormally or
does not permit a normal range of motion in the acetabular socket. Damage can occur to
the articular cartilage, or labral cartilage, or both. Treatment options range from conservative
to arthroscopic to open surgery.
Overview
FAI is regarded as a cause of premature hip osteoarthritis and is characterized by abnormal
contact between the proximal femur and rim of the acetabulum. In most cases, patients
present with a deformity in the femoral head, or acetabulum, a poorly positioned femoral-acetabular
junction, or any or all of the foregoing. A combination of certain factors may predispose
to some form of FAI, predominantly, a marginal developmental hip abnormality together with
environmental factors such as activities involving recurrent motion of the legs within a supraphysiologic
range. Three types of FAI are recognized. The first
involves an excess of bone along the upper surface of the femoral head, known as a Cam
deformity.. The second is due to an excess of growth of the upper lip of the acetabular
cup and is known as a 'Pincer' deformity. Colloquially, these are referred to as 'Cam'
and 'Pincer'. The third is a combination of the two. Studies have suggested that 'Cam'
deformities are more common in the male, while 'Pincer' deformities are more common in females.
However, the most common situation, approximately 70%, is a combination of both. A complicating
issue is that some of the radiographic findings of FAI have also been described in asymptomatic
subjects. Consequently, the true frequency of femoroacetabular impingement is currently
under debate, but the ultimate result is increased friction between the acetabular cup and femoral
head which may result in pain and loss or reduction of hip function.
Those presenting with FAI tend to have an active lifestyle. However, FAI-related pain
may occur during normal activity such as sitting down and standing up, or getting in and out
of a car or truck. Diagnosis
FAI-related pain is often felt in the groin, but may also be experienced in the lower back
or around the hip. The diagnosis, often with a co-existing labral tear, typically involves
physical examination in which the range of motion of the hip is tested. Limited flexibility
leads to further examination with x-ray, providing a two-dimensional view of the hip joints.
Additional specialized views, such as the Dunn view, may make x-ray more sensitive.
Subsequent imaging techniques such as CT or MRI may follow producing a three-dimensional
reconstruction of the joint to evaluate the hip cartilage, demonstrate signs of osteoarthritis,
or measure hip socket angles. It is also possible to perform dynamic simulation of hip motion
with CT or MRI assisting to establish whether, where, and to what extent, impingement is
occurring. Treatment
The treatment of FAI varies. Conservative treatment includes reducing levels of physical
activity, anti-inflammatory medication and physiotherapy. Physical Therapy [physiotherapy]
may optimize alignment and mobility of the joint, thereby decreasing excessive forces
on irritable or weakened tissues. It may also identify specific movement patterns that may
be causing injury. Due to the frequency of diagnosis in adolescents
and young adults, various surgical techniques have been developed with the goal of preserving
the hip joint. Surgery may be arthroscopic or open, peri-acetabular or rotational osteotomies
being two common open surgical techniques employed when an abnormal angle between femur
and acetabulum has been demonstrated. These primarily aim to alter the angle of the hip
socket in such a way that contact between the acetabulum and femoral head are greatly
reduced, allowing a greater range of movement. Femoral sculpting may be performed simultaneously,
if required for a better overall shape of the hip joint. It is unclear whether or not
these interventions effectively delay or prevent the onset of arthritis. Well designed, long
term studies evaluating the efficacy of these treatments have not been done.
A 2011 study analyzing current surgical methods for management of symptomatic femoral acetabular
impingement, suggested that arthroscopic method had surgical outcomes equal to or better than
other methods with a lower rate of major complications when performed by experienced surgeons.
Trivia Notable persons who suffered hip impingements:
Lady Gaga, American popstar Alex Rodriguez, American baseball player
Carlos Delgado, Puerto Rican baseball player Elliott Hewitt, Welsh footballer
Chris Porter, English footballer Geoff Schwartz, NFL American football player
Tyson Gay, American sprinter Nick Willis, New Zealand Olympian
Lamarcus Aldridge, NBA Power Forward Chase Utley, Philadelphia Phillies Second
Baseman Brian Roberts, Baltimore Orioles Second Baseman
Jerry Hairston Jr., LA Dodgers Second Baseman Alex Gordon, Kansas City Royals Third Baseman
Bernard Tomic, Australian Tennis Player Zach Banner, USC Trojan Football Player
References
Further reading Lewis CL, Sahrmann SA. "Acetabular labral
tears". Phys Ther 86: 110–21. PMID 16386066. External links
Hip Impingement Awareness website written by ex FAI patient, Louisa Weeks Browning
Hip Preservation Awareness, information and support for hip impingement, hip dysplasia,
and related issues in young adults IMPAKT-HiP Study by the Arthritis Research
Centre of Canada