XXXX is the most common reason for revision hip arthroscopy: a three-dimensional CT study.

@entity1 @entity85 @entity13852 @entity571
BACKGROUND: Previous studies have reported @entity85 to be the most common reason for revision hip arthroscopy. An awareness of the most frequent locations of the @entity85 may be critical to minimize these failures. QUESTIONS/PURPOSES: The purposes of this study were to (1) define the three-dimensional (3-D) morphology of hips with residual symptoms before revision femoroacetabular impingement (FAI) surgery; (2) determine the limitation in range of motion (ROM) in these @entity1 using dynamic, computer-assisted, 3-D analysis; and (3) compare these measures with a cohort of @entity1 who underwent successful arthroscopic surgery for FAI by a high-volume hip arthroscopist. METHODS: Between 2008 and 2013, one senior surgeon ( @entity13852 ) performed revision arthroscopic FAI procedures on @entity1 with residual FAI @entity85 after prior unsuccessful arthroscopic surgery; all of these 47 @entity1 (50 hips) had preoperative CT scans. Mean @entity1 age was 29    9 years (range, 16-52 years). Three-dimensional models of the hips were created to allow measurements of femoral and acetabular morphology and ROM to bony impingement using a validated, computer-based dynamic imaging software. During the same time period, 65 @entity1 with successful primary arthroscopic treatment of FAI by the same surgeon underwent preoperative CT scans for the symptomatic contralateral hip; this group of 65 @entity1 thus fortuitously provided postoperative evaluation of the originally operated hip and served as a control group. A comparison of the virtual correction with the actual correction in the primary successful FAI treatment cohort was performed. Correspondingly, a comparison of the recommended virtual correction with the correction evident at the time of presentation after failed primary surgery in the revision cohort was performed. Analysis was performed by two independent observers (JRR, @entity571 ) and a paired t-test was used for comparison of continuous variables, whereas chi-square testing was used for categorical variables with p < 0.05 defined as significant. RESULTS: Ninety percent (45 of 50) of @entity1 undergoing revision surgery for symptomatic FAI had @entity85 ; the mean maximal alpha angle in revision hips was 68      16   and was most often located at 1:15, considering the acetabulum as a clockface and 1 to 5 o'clock as anterior independent of side. Twenty-six percent (13 of 50) of hips had signs of overcoverage with a lateral center-edge angle greater than or equal to 40  . Dynamic analysis revealed mean direct hip flexion of 114      11   to osseous impingement. Internal rotation in 90   of hip flexion and flexion, adduction, internal rotation to osseous contact were 28      12   and 20      10  , respectively, which were less than those in hips that had underwent hip arthroscopy by a high-volume hip arthroscopist (all p < 0.001). CONCLUSIONS: We found marked radiographic evidence of @entity85 in @entity1 with residual symptoms compared with @entity1 with successful results with @entity85 present in the large majority of @entity1 (45 of 50 [90%]) undergoing residual FAI surgery. We recommend careful attention to full 3-D resection of impinging structures.
