Postarthroscopy Imaging in Femoroacetabular Impingement: Persistent Pain May Be Due to an Insufficient Correction of Preoperative Abnormalities.

Purpose  The purpose of this study was to evaluate the effect of correction of abnormal radiographic parameters on postoperative pain in a group of patients treated arthroscopically for femoracetabular impingement (FAI). Methods  A retrospective study was performed on 23 patients affected by mixed-type FAI and treated arthroscopically. There were 11 males and 12 females with a mean age of 46.5 (range: 28-67) years. Center-edge (CE) and α angles were measured on preoperative and postoperative radiographic and magnetic resonance imaging (MRI) studies and were correlated with persistent pain at follow-up. Results  The mean preoperative CE and α angles were 38.6 ± 5.2 and 67.3 ± 7.2 degrees, respectively. At follow-up, in the 17 pain-free patients, the mean pre- and postoperative CE angle were 38.1 ± 5.6 and 32.6 ± 4.8 degrees, respectively, whereas the mean pre- and postoperative α angles at MRI were 66.3 ± 7.9 and 47.9 ± 8.9 degrees, respectively. In six patients with persistent hip pain, the mean pre- and postoperative CE angles were 39.8 ± 3.6 and 35.8 ± 3.1 degrees, respectively, whereas the mean pre- and postoperative α angles were 70.0 ± 3.9 and 58.8 ± 2.6 degrees, respectively. Mean values of all the analyzed radiological parameters, except CE angle in patients with pain, improved significantly after surgery. On comparing patient groups, significantly lower postoperative α angles and lower CE angle were observed in patients without pain. Conclusion  In case of persistent pain after arthroscopic treatment of FAI, a new set of imaging studies must be performed because pain may be related to an insufficient correction of preoperative radiographic abnormalities. Level of Evidence  Level IV, retrospective case series.