Introduction

Autologous chondrocyte implantation presents a viable alternative to microfracture in the repair of damaged articular cartilage of the knee; however, outcomes for patellar lesions have been less encouraging. ChondroCelect (CC) is an innovative, advanced cell therapy product consisting of autologous cartilage cells expanded ex vivo through a highly controlled and consistent manufacturing process.

Purpose: Long-term follow-up was to determine clinical benefit of ChondroCelect (CC) in the repair of full-thickness femoral cartilage lesions as compared to microfracture (MF).

Methods: In a randomized controlled clinical trial CC (n=57) was compared to MF (n=61) in patients aged 18 to 50 years with single ICRS grade III/IV symptomatic cartilage defects of the femoral condyles. Clinical improvement was measured up to 36 months using the KOOS (Knee injury and Osteoarthritis Outcome Score). Safety was monitored throughout the study.

Results: At baseline, KOOS was comparable between treatment groups (Mean ± SD: CC, 56.30 ± 13.61 and MF, 59.53 ± 14.95). Improvement from baseline in adjusted mean ± SE for the Overall KOOS was 21.25 ± 3.60 for the CC group vs. 15.83 ± 3.48 for the MF group at 36 months. When using the mixed linear model analysis at 36 months, statistically significantly greater improvements were demonstrated in the CC group vs. the MF group in change from baseline for the overall KOOS (D 7.60%, P = 0.018), as well as in 4 of 5 KOOS domains (activities of daily living, pain, symptoms/stiffness, and quality of life). Percentages of treatment responders were 83% (n = 34/41) vs. 62% (n = 31/50) based on the KOOS for CC and MF groups, respectively. Two (3.9%) patients in the CC group and 7 (11.5%) patients in the MF group underwent a re-intervention and were therefore considered treatment failures. Both treatments were well tolerated and the proportion of patients reporting AEs diminished over time, indicating stabilization of the patients’ condition.

Conclusions: Implantation of ChondroCelect in the treatment of articular cartilage defects of the femoral condyles shows superior clinical benefit at 36 months vs. microfracture. Structural superiority in favour of the ChondroCelect group was previously demonstrated at 1 year follow up.

Purpose: A three-year evaluation of long-term clinical efficacy of Characterized Chondrocyte Implantation (CCI) compared to microfracture (MF), in the repair of symptomatic cartilage defects of the femoral condyles at 36 months post-surgery.

Materials and Methods: In a prospective, randomized, controlled, multicenter trial, CCI was compared to MF in patients aged 18–50 years with a single symptomatic ICRS grade III–IV lesion of the knee. Clinical outcome was measured 36 months after surgery by means of the KOOS, VAS for pain and ARS, with a non-inferiority margin preset at 9 % points for KOOS and VAS. Furthermore, response to treatment and progression of knee symptoms were assessed. Treatment failure was monitored throughout the study.

Results: Improvement from baseline was higher in the CCI group (N = 41) compared to the MF group (N = 49) for all clinical outcome parameters. Mean improvement from baseline for Overall KOOS was 22.14 vs. 14.48, respectively, with VAS and ARS scores revealing a similar trend. Responder analysis showed 83% of the patients treated with CCI improving vs. 61% after MF. Additionally, we observed a shift in the proportion of knee symptoms over time (52% vs. 35% of asymptomatic knees at 36 months compared to 2% vs. 8% at baseline in the CCI and MF group respectively). At 36 months, failure rates were low in both groups (n=2 in CCI vs. n=7 in MF).

Conclusions: Previous data have described a superior structural repair after CCI compared to MF at 1 year post-surgery. Continued clinical improvement as well as a favorable responder analysis was demonstrated for CCI compared to MF at 36 months.