Response to Diagnostic Injection in Patients With Femoroacetabular Impingement, Labral Tears, Chondral Lesions, and Extra-Articular Pathology

Purpose: The purpose of this study was to compare the percent relief from injection among subjects with arthroscopic findings of femoroacetabular impingement (FAI) and labral and chondral pathologies while controlling for coexisting extra-articular pathology. Methods: We retrospectively reviewed 72 consecutive subjects (54 female and 18 male subjects), aged 29.9 +/- 10.4 years (range, 16 to 55 years), who underwent hip arthroscopy. Three separate analyses of covariance compared the percent relief after injection between groups based on surgically confirmed type of impingement (none, cam, pincer, or combined), labral pathology (none, mild, or torn), and chondral pathology (none, mild acetabular abnormality, acetabular delamination, or femoral lesion) while controlling for the presence of extra-articular pathology (iliotibial band, iliopsoas tendinopathy, or bursitis). Results: The results of analysis 1 (F-3,F-67 = 1.96, P = .128, partial eta(2) = .081) and analysis 2 (F-2,F-68 = 0.008, P = .992, partial eta(2) = .000) indicated no significant main effect for FAI and labral pathology, respectively, on percent relief from injection. The results for analysis 3 indicated a significant main effect for chondral pathology of the hip on the percent relief from injection (F-3,F-67 = 3.03, P < .05, partial eta(2) = .128). Post hoc analysis showed that those with mild chondral pathology of the acetabulum and those with acetabular delamination had significantly greater percent relief compared with those without chondral pathology. Extra-articular pathology did not influence the percent relief from injection in any of the analyses. Conclusions: Subjects with chondral damage had greater relief from injection than those without, regardless of severity. The presence and severity of FAI and labral pathology did not influence the percent relief from injection. Concurrent extra-articular pathology did not alter the interpretation of the percent relief from injection. Therefore the interpretation and diagnostic value of an anesthetic injection in those with primary intra-articular pathology does not need to be altered by the presence of coexisting extra-articular hip pathology.