FAI (femoroacetabular impingement) normally occurs due to bony abnormality at either:

• the femoral head (CAM type) or
• the acetabulum (PINCER type)
• or a combination of both (Pun et al, 2015)

This leads to abnormal compression/contact between the acetabular labrum and head/neck junction which can then damage the labrum or articular cartilage (NICE, 2011). Repetition of this abnormal contact may result in a discrete tear of the labrum (Pun et al, 2015). This can also be caused by varying levels of trauma to the hip in the absence of deformity.

It is worth noting that a large percentage of the population may have asymptomatic labral tears (Frank et al, 2015).  The cause of FAI is thought to be multifactorial and could be due factors such as a slipped capital femoral epiphysis or other morphological malformations such as coxa recta and coxa profunda.  FAI may lead to osteoarthritis of the hip (Wall et al, 2013).

Symptomatic presentation of both conditions (FAI and labral tear) in isolation or combination, may be very similar.  Symptoms are normally felt deep in the anterior hip (less commonly over the lateral hip or buttock) (Burnett et al, 2006).  Patients may indicate a “C sign” distribution by holding their hand around the affected hip (Pun et al 2015).

Pain is often reproduced by repetitive, forceful or prolonged hip flexion (e.g. sitting, squatting or standing) (NICE, 2011).  Pivoting, leaning forward and getting in and out of a car may also aggravate symptoms. Patients may describe a sudden (e.g. traumatic labral tear) or more insidious (e.g. repetitive degeneration) onset. They may also complain of clicking, catching or locking during active range of motion.

Participation in sporting activities involving weight training or loading is believed to be a risk factor for the development of symptoms (NICE 2011).

Prevalence

Rankin et al (2015) carried out a retrospective review of 894 cases of chronic hip and groin pain seen by a sports medicine consultant over a five year period. Of these 55.98% had hip joint pathology of which the majority had FAI (40%) and labral tears (33%).

Three recent systematic reviews (Tijssen et al, 2012, Reiman et al, 2015 and Pacheco, 2016) looked at the diagnostic accuracy and validity of tests for FAI / labral tear. They concluded that there is insufficient quality evidence to recommend any one specific test, however higher levels of specificity and sensitivity were noted for the FADDIR and FABER tests.

FADDIR (Flexion-Adduction-Internal Rotation) Test (Video Link)

This is the most commonly reported test. In this manoeuvre the leg is passively moved into:

• 90˚ of hip and knee flexion
• adduction
• then internal rotation with end of range overpressure to both movements.

Positive result on reproduction of patient’s symptoms. Meta-analysis of this test suggests it has screening accuracy only (Reiman et al 2015).

FABER (Flexion-Abduction-External Rotation test) (Video Link) can also be used to aid diagnosis of FAI.

Patient reported Outcome Measures

1. Hip Outcome Score (HOS) has the greatest amount of clinometric evidence and is the most proven instrument for use in the FAI population. (Lodhia et al, 2011)
2. The Non-Arthritic Hip Score
3. 12-item modified Western Ontario and McMaster Universities Osteoarthritis are also commonly used

Plain x-ray may be helpful in demonstrating CAM or PINCER deformities (Crawford et al 2005).  However Magnetic Resonance Arthrography has been shown to be superior to basic Magnetic Resonance Imaging in detection of intra-articular pathology (Burgess et al, 2011).

Both would be carried out on escalation to Orthopaedics after a period of limited benefit with conservative treatment.

Optimise pain management

Avoid aggravating factors (EOR flexion/impact)

Postural re-education (sitting and standing)

Correct muscle imbalance

Patient centred care

Treatment should take into account individual patient needs, preferences, expectations and functional status. Clinical reasoning should inform treatment, based on subjective and objective findings. Good communication between therapist and patient is essential if a successful outcome is to be achieved. Treatment options should be clearly explained so that patients can make informed decisions with regard to their care and management.

Evidence based strategies

There is high promotion of the potential benefits of conservative treatment in the literature but currently no quality experimental evidence to demonstrate this (Wall et al, 2013) : Grade 2++. However various interventions have been suggested including:

Activity Modification
Including rest and avoidance of impingement positions (NICE 2011, Clohisy et al 2009, Emara et al, 2011) : for example altering how get in and out of car.

Postural Re-Education
Including advice on seating posture and ergonomics. Postural corrections should aim to reduce stress on the anterior structures of the hip in all functional positions eg. Sitting and standing.

Optimising muscle balance and strength
Hip muscle weakness has been demonstrated in subjects with FAI/labral tears in the flexor (Casartelli et al, 2011 and Dilani Mendis et al, 2014) and abductor, adductor and external rotator groups (Casartelli et al, 2011).

As patient progresses advise avoid running straight narrow trails – running zig/zag or wide trails (to avoid IR of LL’s)

NSAIDs (NICE, 2011)

Non evidence based strategies

Passive ROM

Stretching

Progressing as expected (up to 3 Rxs) before discharge or onward referral.

Refer to ortho, GP, other.

Escalation

NICE (2011) suggest a trial of conservative treatment may be offered in treatment of FAI but give no guidelines on how long this trial should last.

Kassarjian et al (2008) suggest a 3 to 6 month trial of rehabilitation with escalation for surgical opinion if this fails.  This seems to correlate with the findings of Emara et al (2011) who demonstrated benefits in function and symptoms with conservative treatment at an initial measure of 6 months post baseline.

Surgery

Numerous surgical techniques are described as treatment for FAI. The aim of surgery is to correct the underlying bony abnormality causing impingement hence restoring optimal joint congruency. This could involve osteo chondroplasty in the case of CAM impingement to remove the excess bone at the femoral neck or removal of bone from the rim of the acetabulum in the case of a pincer impingement. Damaged cartilage or labrum will also be repaired/debrided or reconstructed as required during the surgery. The surgery can be open or arthroscopic.

A Cochrane review published in 2013 concluded that while all 11 shortlisted studies demonstrated an improvement in patient reported pain, function and quality of life following surgery, the studies lacked an appropriate comparator or control group to show the true treatment effect of surgery. Ayeni et al (2014) concluded that in the case of FAI with a labral tear, repair was superior to debridement of the labral tissue where possible.

Predictors of outcome of surgery are thought to be linked to pre-existing osteoarthritic changes in the joint (Gicquel et al, 2014).

Hip Outcome Score

Burgess, R., Rushton, A., Wright, C. and Daborn, C. 2011. The validity and accuracy of clinical diagnostic tests used to detect labral pathology of the hip: A systematic review. Manual Therapy,16:318-326 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Burnett, S., Della Rocca, G., Prather, H., Curry, M., Maloney, W. and Clohisy, J. 2006. Clinical presentation of patients with tears of the acetabular labrum. The Journal of Bone and Joint Surgery, 88-A (7): 1448-1457 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Crawford, J. and Villar, R. 2005. Current concepts in the management of femoroacetabular impingement. The Journal of Bone and Joint Surgery, 87-B(11): 1459-1462 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Frank, J., Harris, J., Erickson, B., Slikker, W., Bush- Joseph, C., Salata, M. and Nho, S.J. 2015. Prevalence of Femoroacetabular Impingement Imaging findings in Asymptomatic Volunteers: A Systematic Review. Arthroscopy: The Journal of Arthroscopic and Related Surgery 31(6): 1199-1204 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Lodhia, P., Slobogean, G.P., Noonan, V.K., and Gilbart, M.K. 2011. Systematic Review with Video Illustration Patient-Reported Outcome Instruments for Femoroacetabular Impingement and Hip Labral Pathology: A Systematic Review of the Clinimetric Evidence. Arthroscopy: The Journal of Arthroscopic and Related Surgery, 27 (2): 279-286 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

National Institute for Health and Clinical Excellence. Interventional Procedures Programme. 2011. Interventional procedure overview of arthroscopic femoro-acetabular surgery for hip impingement syndrome. IP 365_2 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Pacheco-Carrillo, A. and Medina-Porqueres, I. 2016. Physical Examination Tests for the diagnosis of Femoroacetabular Impingement. A Systematic Review. Physical Therapy in Sports doi:10.1016/j.ptsp.2016.01.002 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Pun, S., Kumar, D. and Lane, N. 2015. Femoroacetabular Impingement. Arthritis and Rheumatology, 67(1) 17-27 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Reiman, M.P., Goode, A.P., Cook, C.E., Holmich, P. and Thorborg, K. 2015. Diagnostic accuracy of clinical tests for the diagnosis of hip femoroactetabular impingement/labral teat: a systematic review with meta-analysis. British Journal of Sports Medicine Vol 49:811 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Rankin, A., Bleakley, C. and Cullen, M. 2015. Hip joint pathology as a leading cause of groin pain in the sporting population. A 6 year review of 894 cases. The American Journal of Sports Medicine, 43(7):1698-1703 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Tijssen, M., van Cingel, R., Willemsen, L. and de Visser, E. 2012. Diagnostics of Femoroacetabular Impingement and Labral Pathology of the hip: A Systematic Review of the Accuracy and Validity of Physical Tests. Arthroscopy: The Journal of Arthroscopic and Related Surgery 28 (6): 860-871 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

Wall, P.D.H., Fernandez, M., Griffin, D. and Foster, N. 2013. Nonoperative Treatment For Femoroacetabular Impingement: A systematic review of the Literature. Physical Medicine and Rehabilitation 5(5):418-426 Link Here (link correct as of 22/01/21). NHS Scotland Athens username and password may be required.

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