Arthroscopic Analysis of the Radiologic Abnormalities of the Hip Associated with Anterior Femoroacetabular Impingement

ABSTRACT

PURPOSE: We wanted to arthroscopically analyze the femoral osseous abnormalities (bumps) in hips with anterior femoroacetabular impingement (FAI) and the other radiologic abnormalities of the hip joint associated with this. MATERIALS AND METHODS: We retrospectively reviewed the radiographs of 45 patients (51 hips) who underwent arthroscopic treatment under the impression of FAI from January to August, 2008. The indications for surgery included persistent hip pain, the absence of advanced osteoarthritis, physical examination or MRA findings consistent with an acetabualr labral tear. Preoperative and postoperative plain radiographs (pelvis AP, frog-leg lateral, cross table lateral and the false profile view) were taken. As the occasion demanded, 3D-CT or MRA were performed. RESULTS: For the radiologic findings, a decreased head-neck offset (<8 mm) was seen in 15 hips. Femoral bumps were seen in 26 hips and among them, 11 hips were associated with acetabular retroversion, 5 hips were associated with a prominent acetabular rim and 13 hips were located on the flattening of the neck due to a decreased offset. Pistol grip deformity was found in 21 hips and acetabular retroversion was done in 32 hips. Regarding the secondary changes, spurs on the acetabulum of the femur were found in 14 hips and femoral bony cysts were found in 23 hips. Arthroscopically, all the hips had acetabular degenerative labral tear and the acetabular cartilage was injured in 32 hips (62.7%). Among them, 25 hips underwent acetabular retroversion. CONCLUSION: Femoral osseous abnormalities are seen in various locations and these abnormalities have various shapes. A considerable number were associated with pincer impingement and they could produce a 'kissing lesion' between the acetabulum and femur. Identification of these abnormalities on radiographs aids confirming FAI in hips with symptomatic early osteoarthritis.