Autologous Chondrocyte Implantation Improves Knee-Specific Functional Outcomes and Health-Related Quality of Life in Adolescent Patients

Abstract

Background: Existing studies of autologous chondrocyte implantation (ACI) in adolescent patients have primarily reported outcomes that have not been validated for cartilage repair and have failed to include measures of general health or health-related quality of life. Purpose: This study assesses validated knee-specific functional outcomes and health-related quality of life after ACI in adolescent patients. Study Design: Case series; Level of evidence, 4. Methods: Patients younger than 18 years who underwent ACI between 1999 and 2011 with a minimum 2-year clinical follow-up were identified from a prospectively collected database. A total of 37 patients were included in the analysis. Patient demographic data and pre- and postoperative functional outcomes scores were collected and chondral lesion characteristics were assessed. Primary outcome measures were the International Knee Documentation Committee (IKDC) subjective score and the Knee Injury and Osteoarthritis Outcome Score–Quality of Life (KOOS-QOL) subscore; secondary outcome measures were Short Form–12 (SF-12) and other KOOS subscores. In subgroup analyses, we assessed whether primary outcome results differed based on lesion location, concurrent meniscal allograft transplantation (MAT), and subsequent surgery after ACI. Results: Study patients had a mean 4.6 ± 2.4 years of follow-up, a mean age of 16.7 ± 1.5 years, and a mean lesion size of 4.0 ± 2.2 cm2. The IKDC subjective score improved from 34.9 preoperatively to 64.6 postoperatively (mean improvement, 29.7 points [95% CI, 20.7 to 38.7 points]; P < .001) and the KOOS-QOL subscore improved from 24.3 to 55.3 (mean improvement, 31.0 points [95% CI, 21.3 to 40.7 points]; P < .001) at final follow-up. All other KOOS subscales and the SF-12 physical component score also showed significant improvements ( P < .008 in all cases), whereas the SF-12 mental component score showed no improvement ( P = .464). There was a 37.8% rate of subsequent surgery after ACI (most commonly, chondral debridement [54%], meniscectomy [11%], microfracture [9%], and loose body removal [9%]). Subgroup analysis showed no effect of lesion location, concurrent MAT, or subsequent surgery on improvement in IKDC subjective scores and KOOS-QOL subscores ( P > .05 in all cases). Conclusion: ACI is an effective treatment for adolescent patients with symptomatic, large chondral lesions, resulting in significant improvements in knee-specific functional outcome scores and health-related quality of life scores. Although patients must be cautioned on the relatively high reoperation rate (37.8%) and limitations in knee function even after ACI, all patients in this study exhibited improvements over preoperative knee function at the most recent follow-up regardless of ACI location, concurrent MAT, or subsequent surgery.