Prevalence of radiological signs of femoroacetabular impingement in patients presenting with long-standing adductor-related groin pain

Objective A decreased range of motion (ROM) of the hip joint is known to predispose to athletic groin injury. Femoroacetabular impingement (FAI) of the hip leads to a reduced ROM. This study examined the prevalence of radiological signs of FAI in patients presenting with long-standing adductor-related groin pain (LSARGP). Design Prospective case series. Setting Outpatient Sports Medicine Department. Patients 34 athletes with LSARGP defined as pain on palpation of the proximal insertion of adductor muscle and a painful, resisted adduction test. Assessment A clinician blinded to the results of the radiological assessment performed a physical examination: iliopsoas length, hip ROM and anterior hip impingement test. Anteroposterior pelvic radiographs were examined by a second blinded clinician for the presence of: pistol grip deformity, centrum-collum-diaphyseal angle, femoral head neck ratio, coxa profunda, protrusio acetabuli, lateral centre edge angle, acetabular index and cross-over sign. Results The prevalence of radiological signs of FAI was 94% (64/68). The mean number of radiological signs in hips with LSARGP was 1.84 (range 0-4, SD 1.05) and 1.96 (range 0-5, SD 1.12) in asymptomatic groins (p=0.95). The anterior hip impingement test was positive in nine cases. There was no relationship with the number of radiological signs (p=0.95). There was no correlation between hip ROM and the number of radiological signs (p=0.37). Conclusion Radiological signs of FAI are frequently observed in patients presenting with LSARGP. Clinicians should be aware of this fact and the possible lack of correlation when assessing athletes with groin pain.