Functional Outcomes and Cam Recurrence After Arthroscopic Treatment of Femoroacetabular Impingement in Adolescents

Abstract

To compare the functional outcomes after arthroscopic treatment of femoroacetabular impingement (FAI) in adolescent patients and non-adolescent patients, and to report on the rate of cam recurrence within 2years after femoral osteoplasty in a limited sample of the adolescent group. From 2010 to 2014, patients younger than 18years with symptomatic FAI (alpha angle >50°) who underwent hip arthroscopy with minimum 2-year follow-up or reoperation were identified. A group of non-adolescent patients with identical inclusion criteria, except age of 18years or older, was also identified for comparison. In addition, a separate group of adolescent patients with 2-year postoperative radiographs was reviewed for cam recurrence. Demographic data, operative data, and radiographic and clinical outcomes (modified Harris Hip Score [mHHS], Hip Outcome Score-Activities of Daily Living [HOS-ADL], Hip Outcome Score-Sport-Specific Subscale [HOS-SSS], and International Hip Outcome Tool 33 [iHOT-33] score) were collected. We identified 34 adolescent patients (38 hips) with an average age of 16years (range, 13-17years). The mean clinical follow-up period was 36.1 ± 11.6months (range, 24.1-71.7months) and 29.6 ± 2.4months (range, 27.9-31.3months) without and with reoperation, respectively. A control group of 296 non-adolescent patients (306 hips), with a mean age of 31years (range, 18-59years), was identified as our non-adolescent group. The mean clinical follow-up period was 34.1 ± 11months (range, 24.0-77.4months) and 15.1 ± 9.1months (range, 3.6-34.6months) without and with reoperation, respectively. Significant improvement was noted in adolescents in the changes in outcome scores (mHHS, 22.2 [95% confidence interval (CI), 15.4-29.0]; HOS-ADL, 18.6 [95% CI, 11.9-25.2]; HOS-SSS, 33.5 [95% CI, 24.5-42.5]; and iHOT-33 score, 30.5 [95% CI, 21.8-39.2]; P < .001). Similar improvements were observed in non-adolescents (mHHS, 21.0 [95% CI, 19.0-23.0]; HOS-ADL, 16.6 [95% CI, 14.6-18.6]; HOS-SSS, 30.1 [95% CI, 26.6-33.6]; and iHOT-33 score, 34.9 [95% CI, 31.5-38.3]; P < .001). There was no evidence of a difference in follow-up survey scores between groups (P > .203). Revision surgery was required in 2 adolescent hips (5.3% [95% CI, 1.5%-17.3%]) and 19 non-adolescent hips (6.2% [95% CI, 4.0%-9.5%]). Minimum 2-year radiographs were available for review in 24 adolescent patients (30 hips). The alpha angle (mean ± standard deviation) was reduced from 55.4° ± 12.1° preoperatively to 38.7° ± 4.9° at 6weeks postoperatively (mean difference,-16.4° [95% CI,-19.8° to-12.9°]; P < .001). At 2years, the alpha angle remained at 39.2° ± 11.2°, which did not differ from 6-week measurements (mean difference, 0.5° [95% CI,-2.9° to 3.9°]; P= .784). There were no cases of cam recurrence (0% [95% CI, 0%-11.4%]). Significant improvement in clinical outcomes can be anticipated after arthroscopic treatment of FAI in adolescents. From a limited sample of our adolescent population, the risk of cam recurrence appears low; however, further follow-up is needed to ensure this does not represent a biased sample of the initial population. Level III, retrospective comparative study.