Skeletally Immature Adolescents With Open Physes Show Similar Outcomes From Hip Arthroscopy as Skeletally Mature Adolescents With Closed Physes

Purpose To report short‐term outcomes of primary hip arthroscopy in skeletally immature adolescents with open physes (OP) and to compare their results with a propensity‐matched group of skeletally mature adolescents with closed physes (CP). Methods Data were reviewed for patients undergoing arthroscopy for the treatment of femoroacetabular impingement syndrome and labral tears between February 2008 and June 2021. Patients were excluded if they had previous ipsilateral hip conditions, hip dysplasia (lateral center‐edge angle < 18°), previous ipsilateral surgery, preoperative Tonnis grade >1, or were older than 19 years. Patients were included in the OP group if they had open proximal femoral growth plates, Risser stage ≤4, and minimum 2‐year follow‐up. OP hips were matched to CP hips in a 1:1 ratio by age, sex, and body mass index. Patient‐reported outcomes (PROs), clinically meaningful thresholds, secondary surgeries, and complications were compared. Results Thirty OP hips were matched with 30 CP hips. The mean age of the OP group and control group was similar (OP 14.96 yr; CP 15.01 yr, P = .94). Significant and similar improvement was seen for all PROs in both groups ( P < .05). The OP group had higher preoperative values for modified Harris Hip Score and Hip Outcome Score Sport‐Specific Subscale than the CP group ( P < .05), yet both groups achieved similar postoperative values for all evaluated PROs ( P > .05). The OP and CP groups met clinically meaningful thresholds and underwent revision arthroscopy at similar rates ( P > .05). No complications, bony regrowth, or growth disturbances were reported. Conclusions Skeletally immature adolescents with OP showed favorable short‐term outcomes after primary hip arthroscopy. When compared with a propensity‐matched control group of CPs, OPs had similar PROs, met clinically meaningful thresholds, and underwent revision hip arthroscopy at similar rates. Longitudinal radiographic analysis indicated no bony regrowth to occur in both groups. Level of Evidence Level III, retrospective case control study.