![]( "Cam defect variation of FAI")
A recent paper from the Mayo Clinic in Rochester, MN (Yuan et al, 2013) appeared in the American Journal of Sports Medicine which brought to light that screening the hip range of motion (ROM) in young athletes might be worthwhile to identify problems that might be in that athlete’s future. Yuan, et al found that a simple modified flexion/adduction/internal rotation (FADIR) impingement test in asymptomatic athletes was able to pick up early stages of cam type of femoracetabular impingement (FAI). Specifically, they assessed 226 athletes for internal rotation deficits by flexing the supine athlete’s hip to 90 degrees, and then applying adduction and internal rotation. They also received the impingement test which was essentially the same test with hip flexion performed to endrange. 19 of those athletes (8%) demonstrated IR <10 degrees and 34 of 38 hips in those athletes demonstrated <10 degrees IR-ROM. Only 18 of those hips had pain with the impingement test. Of those with positive findings, 13 chose to participate in the study. A control group of 13 was chosen from normals from the the original N=226 cohort and both groups received Xray, MRI, and a subsequent manual exam.
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Recruitment for Yuan, et al, 2013.
Significant findings included:
- Mean alpha angle on MRI was 44.3 in the control group and 58.1 in the study group.
- 86% of those asymptomatic hips with clinical signs in the study group demonstrated abnormal findings on plain film Xray.
- >2/3 of the study group had MRI demonstrated pathology vs. 1/3 of the study group. The more accurate MRA assessment was not ok’d by IRB for pediatric population.
The final paragraph is excerpted below, which asks some important questions we need to answer in future studies:
“As more information about the natural history of FAI becomes available, it will be important to understand how and why the pathoanatomy of FAI leads to future hip injuries in some patients. Specifically, if there is a way to easily screen for those with reduced hip clearance, does counseling those patients on avoiding activities that require forced hip motion to the extreme reduce the development of symptomatic FAI or even OA in the future? Currently, we do not recommend any sports-related or activity modification based on the results of a ‘‘positive’’ screening examination result. This study, however, provides new data that can be used to compare future longitudinal natural history studies. Obviously, the data on the natural history of FAI are necessary before definitive recommendations regarding activity modification for the adolescent athlete can be made, such as avoiding ballet or playing as a goalie in hockey. Additionally, there is probably a little role for prophylactic surgery. However, our findings suggest that a simple hip examination may have utility as a screening test in asymptomatic patients to detect the hip at risk of future pathological changes secondary to impingement during high-risk activities.”
A few other questions came up for me in my review of this material. I’ve included those questions and links for those that are interested in chasing this out a bit further.
1. How do post surgical FAI hips fare in kids, adolescents and adults?-(
Philippon 2008,
Philippon 2009) Pretty good…if you ask a surgeon.
2. What’s the current thinking on most effective clinical exam for the hip? (
Martin et al, 2006) A test cluster is suggested but has not yet been thoroughly researched.
3. What are the methods of assessing the alpha angle in the hip?
From
Taunton on OrthopedicsOne reference site, on AP Xray or MRI, “the alpha angle is formed by a line drawn from the center of the femoral head through the center of the femoral neck, and a line from the center of the femoral head to the femoral head/neck junction, found by the point by which the femoral neck diverges from a circle drawn around the femoral head. At present, the upper end of normal is an alpha angle of 50 – 55 degrees.” Serbian researchers (
Andjelkovic, 2013) recently described a newer method of radiographically assessing the alpha angle on plain film.
4. What other studies implicate the alpha angle in hip pathology? (
Beaule, 2012) Makes one wonder if heavy back squats and ATG cueing in those squats is a good idea in adolescents.
5. If high alpha angle indicates structural predisposition to hip pathology, what exercise and/or rehab can we suggest for our patients?
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In closing, several studies have suggested that in young populations, the presence of FAI in young active patients is likely to lead to significant osteoarthritis in later years.(Ganz, 2003; Tanzer, 2004; Wegner, 2004) In older populations the jury is still out.
Hartofilakidis et al in 2011 performed a retrospective study and tracked 96 asymptomatic, middle-aged hips with radiological evidence of FAI and found “…that a substantial proportion of hips with femoroacetabular impingement may not develop osteoarthritis in the long-term. Accordingly, in the absence of symptoms, prophylactic surgical treatment is not warranted.”
References:
Yuan BJ, Bartelt RB, Levy BA, Bond JR, Trousdale RT, Sierra RJ. Decreased Range of Motion Is Associated With Structural Hip Deformity in Asymptomatic Adolescent Athletes. Am J Sports Med. 2013 May 22.
Philippon MJ, Yen YM, Briggs KK, Kuppersmith DA, Maxwell RB. Early outcomes after hip arthroscopy for femoroacetabular impingement in the athletic adolescent patient: a preliminary report. J Pediatr Orthop. 2008 Oct-Nov;28(7):705-10.
Philippon MJ, Briggs KK, Yen YM, Kuppersmith DA. Outcomes following hip arthroscopy for femoroacetabular impingement with associated chondrolabral dysfunction: minimum two-year follow-up. J Bone Joint Surg Br. 2009 Jan;91(1):16-23.
Andjelković Z, Mladenović D. Measuring the osteochondral connection of the femoral head and neck in patients with impingement femoroacetabular by determining the angle of 2alpha in lateral and anteroposterior hip radiographic images. Vojnosanit Pregl. 2013 Mar;70(3):259-66.
Klaue K, Durnin CW, Ganz R. The acetabular rim syndrome. A clinical presentation of dysplasia of the hip. J Bone Joint Surg Br. 1991 May;73(3):423-9.
Martin RL, Enseki KR, Draovitch P, Trapuzzano T, Philippon MJ. Acetabular labral tears of the hip: examination and diagnostic challenges. J Orthop Sports Phys Ther. 2006 Jul;36(7):503-15.
Ganz R, Parvizi J, Beck M, Leunig M, Notzli H, Siebenrock KA. Femoroacetabular impingement: a cause for osteoarthritis of the hip. Clin Orthop Relat Res. 2003;417:112-120.
