Historically, the hip joint was not routinely considered as a source of hip and groin pain in the athletic population. In the last decade, our understanding of hip joint pathology has progressed significantly on account of the increased availability of magnetic resonance imaging (MRI) and hip arthroscopy.
Pathologies of the hip joint labrum and acetabular rim, once considered exclusive to the paediatric and osteoarthritic population, are now considered common diagnoses in athletes. Anatomical variants of the hip that fall under the umbrella term of femoroacetabular impingement (FAI) are increasingly recognised as potential contributing or causative factors to groin pain. For more information, chapters 28 and 29 of the fourth edition of the Clinical Sports Medicine textbook (@CSM4ed) are dedicated to hip-related groin pain and include an in-depth overview of hip pathologies.
Patients can present to the clinic with generalized hip pain in the presence of normal investigations. However, a recent study1 published in The American Journal of Sports Medicine has shown the opposite to be true. This study observed the prevalence of abnormal MRI findings in an asymptomatic population of forty-five volunteers (mean age 37.8 years) with no history of hip pain, symptoms, injury, or surgery. Results revealed 73% of people had hip abnormalities, with labral tears identified most commonly (69%). Other abnormalities included chondral defects (24%), fibrocystic changes of the femoral head/neck junction (22%), osseous bumps (20%), sub-chondral bone cysts (16%), labral/paralabral cysts (13%), acetabular bone edema (11%), acetabular rim fractures (11%), and ligamentum teres tears (2.2%). Volunteers who were older than 35 years were 13.7 times more likely to have a chondral defect and 16.7 times more likely to have a subchondral cyst.
Consider for a moment that these pathologies were found in an asymptomatic population. Cast your eyes over those numbers again. Seven out of ten asymptomatic individuals participating in this study had a labral tear. One in five had a chondral defect and one in ten had a fracture of the acetabular rim. These data reinforce the importance of giving precedence to the findings of the clinical examination. Although MRI investigations are considered accurate, reproducible and a gold standard method for non-invasive assessment of the hip joint,2 clinicians should always perform a comprehensive, structured clinical assessment to warrant the need for investigations and avoid treating the investigation instead of the presentation.
1. Register B, Pennock AT, Ho CP, et. al. Prevalence of abnormal hip findings in asymptomatic participants: a prospective, blinded study. The American journal of sports medicine 2012 40(12): 2720-4
2. Gold SL, Burge AJ, Potter HG. MRI of hip cartilage: joint morphology, structure, and composition. Clinical orthopaedics and related research 2012 470(12): 3321-31
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