Femoroacetabular impingement (FAI) is a multifactorial hip disease in which pain is a direct result of a collision of femoral head (the ball of the hip joint) with the edge of the acetabula (the socket of the hip joint). The hallmark of the disease is pain provoked by hip flexion. Although impingement occurs during flexion of the hip joint such as with sitting, squatting and lifting the hip. Once the impingement is established the pain may appear on walking, kicking and sporting activities involving body rotation over the planted leg. This occurs because the hip joint labrum becomes damaged and the capsule becomes inflamed. The joint space may not become decreased until the progression of the disease. Labral tears may or may not be present with FAI.
Most common location of pain is in the groin,
however it may appear on the side or the back of the hip.
FAI is a disease of young athletic adults. However, hip impingement also occurs in middle age population as well and account for 10-15 % of adults with any hip diseases. In older adults the changes in the hip joint occur earlier but may manifest later in life.
There are 2 types of FAI; Cam and Pincer deformity. However majority of cases are of a mixed type.
CAM type – is a widening of the femoral neck. Pincer type is when there is an outgrowth of the edge of the bony acetabula.
Hip joint is anatomically the most complex joint in the human body. It is a part of functional unit called lumbopelvic-hip complex and as such plays a decisive role in mobility of this complex .The intrinsic stability of this joint is provided by the labrum and the capsule-ligamentous complex. The labrum is a fibrocartilagenous pad which smoothes the surface of the acetabula providing adherence and congruency to the movement of the femoral head (the ball) in the acetabula (the socket).
The articular surface of the joint is layered with hyaline cartilage- which functions to decrease friction and helps to increase range of motion. The anatomy of the hip is designed in such a way to create negative pressure between the surface of the femur and the acetabula. With Femoroacetabular impingement this pressure is lost.
Research shows that children with abnormal structural development of hip bones are predisposed to developing FAI, however there are many patients with FAI who don’t have any predisposing factors. The collision of the head of femur with an acetabula as an abnormal contact results in decreased range of motion, inflammation, and eventually may lead to wear and tear of the joint cartilage.. Functionally, FAI will lead to hip and pelvic instability, pelvic misalignment, muscle misbalance ,compensatory weight distribution and loss of balance.
Trauma to the hip
Congenital hip dysplasia
Congenital hip dislocation
Significant anterior pelvic tilt
Structural anatomical abnormalities of the hip joint
Clinical history and proper examination is sufficient for consideration of FAI as a diagnosis. Xray may show some abnormality but MRI is much more accurate and preferred in determining the stage and extent of FAI.When surgery is concerned the ultimate modality for diagnosis is CTscan.
Although arthroscopic techniques have been dramatically improved and there is much more research data in the last five years the first treatment of choice is certainly conservative. Research shows that 85% of patients with Femoroacetabular hip impingement will improve with physical therapy.Research also shows that those patients with FAI who prehabed have better outcomes after the surgery.
At NYDNRehab we have extensive experience treating FAI. Based on functional evaluation and gait analysis we create an individualized treatment plan. Treatment options may vary depending on type and stage of the FAI. FAI treatment is always a combination of manual therapy, hip specific physical therapy exercises. We use our unique CAREN (Computer Assisted Rehabilitation Environment) technology to retrain symmetrical weight bearing and equalize weight shifting which is always disturbed in patients with Femoroacetabular impingement. However, in our experience of trying different physical therapy methods for hip impingement pain we found DNS (dynamic Neuromuscular Stabilization) approach to be the most effective.
Patients experience symptoms of hip movement stiffness to sharp pain in the groin after sporting activities.
The sports, which usually lead to FAI, are: soccer, hockey, martial arts, ballet and yoga.
This is a list of anatomical predisposing factors:
Other predisposing factors are more functional or traumatic. These range from direct trauma to distant trauma resulting in alteration of biomechanical relationship in the kinetic chain.
The progression of this disease is interesting occurrence. One may ask himself that if all anatomical predisposing factors are congenital why does one develop symptoms in the 3d or 4th decade of life, (professional athletes develop symptoms in the second decade)?
The answer is simple. In FAI congenital bone anomalies are varied in combination of it’s severity and overplay with joint and movement dysfunction in other regions of the body. Majority of people with these congenital anatomical defects in the hip area may never experience pain or only develop hip arthritis(arthrosis) in 7 the decade of life. This is because these people simply don’t participate in sports or choose sports, which are not damaging to the hip with congenital imperfections.
Many people with FAI suffer from back pain and herniated disc disease for years prior to developing symptoms of hip pain. Majority of these patients are operated for disc hernia without successful outcomes or only with temporary pain relieve.
The golden standard of radiological diagnosis for FAI is special CT scan series. This is, however only necessary in case surgical intervention is entertained as there is enormous dose of radiation involved in this special procedure.
Otherwise, a combination of X- ray with MRI or diagnostic ultrasound and clinical examination can be specific enough for treatment.
FAI pain treatment depends on precise structural and functional diagnosis as well as consideration of compensatory factors, which usually play a significant role in the rehab process. The challenge of conservative treatment of FAI lies in its complexity of presentation, as no FAI patient is similar to another FAI patient as far as rehab is concerned. Also, since hip joint is a major weight bearing joint in the human body it’s gait deviations are engraved in the motor control and the biomechanics of the whole human body.
Femoraceabular (FAI) pain treatment also depends on careful elimination of provoking movement and postures.
Video gait analysis is the best technological modality to tease out and precisely describe all movement aberrations in pelvis and the rest of lower extremity. These aberrations are not visible to human eye and therefore biomechanical relationship of all the components of lower kinetic chain cannot be properly addressed without it.
Please explore our gait analysis page.
Even with all the complexity of the FAI pain syndrome, conservative care is successful in experienced hands within 6-8 weeks in initial presentation and up to 6 month of rehab in chronic cases.
Surgical intervention should only be reserved to professional athletes or very few patients with greater damage of hip intrarticular tissues.
The surgical intervention does not correct the cause of impaired movement but only remove the bone conflicting anatomy.
Since data for arthroscopic FAI repairs is relatively new , we can not estimate yet how successful these surgeries are. Especially giving very , very long recovery from this surgery this type of procedure should only be reserved as a last reserve.
Please check out our pages for the running gait lab, the alter-g treadmill, Biofeedback motor control training with real time force plate analysis, and shockwave therapy to see how these technologies can help you.