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

PURPOSE: 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 2 years after femoral osteoplasty in a limited sample of the adolescent group.

METHODS: From 2010 to 2014, patients younger than 18 years 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 18 years 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.

RESULTS: We identified 34 adolescent patients (38 hips) with an average age of 16 years (range, 13-17 years). The mean clinical follow-up period was 36.1 ± 11.6 months (range, 24.1-71.7 months) and 29.6 ± 2.4 months (range, 27.9-31.3 months) without and with reoperation, respectively. A control group of 296 non-adolescent patients (306 hips), with a mean age of 31 years (range, 18-59 years), was identified as our non-adolescent group. The mean clinical follow-up period was 34.1 ± 11 months (range, 24.0-77.4 months) and 15.1 ± 9.1 months (range, 3.6-34.6 months) 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 6 weeks postoperatively (mean difference, -16.4° [95% CI, -19.8° to -12.9°]; P < .001). At 2 years, 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%]).

CONCLUSIONS: 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 OF EVIDENCE: Level III, retrospective comparative study.