Radiographic prevalence of femoroacetabular impingement in a young population with hip complaints is high.

BACKGROUND Femoroacetabular impingement (FAI) is reportedly a prearthritic condition in young adults that can progress to osteoarthritis. However, the prevalence of FAI is unknown in the young, active population presenting with hip complaints. QUESTIONS/PURPOSES We sought to determine (1) the prevalence of radiographic findings of FAI in a young, active patient population with complaints localized to the region of the hip presenting to primary care and orthopaedic clinics; (2) the percentage of films with FAI with an official reading suggesting the diagnosis; and (3) whether the Tönnis grades of osteoarthritis corresponded to the findings of FAI. METHODS We performed a database review of pelvic and hip radiographs obtained from 157 young (mean age 32 years; range, 18-50 years) patients presenting with hip-related complaints to primary care and orthopaedic clinics. Radiographs were analyzed for signs of FAI (herniation pits, pistol grip deformity, center-edge angle, alpha angle, and crossover sign) and Tönnis grade. Radiology reports were reviewed for a diagnosis of FAI. RESULTS At least one finding of FAI was found in 135 of the 155 patients (87%). Four hundred thirteen of 487 radiographs (85%) had been read as normal and one read as showing FAI. Tönnis grades did not correlate with radiographic signs of FAI. CONCLUSIONS Radiographic evidence of FAI is common in active patients with hip complaints. Increased awareness of FAI in primary care, radiology, and orthopaedic clinics and additional research into the long-term effects of management are warranted. LEVEL OF EVIDENCE Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.