Midterm to Long-Term Longitudinal Outcome of Autologous Chondrocyte Implantation in the Knee Joint

Abstract

Autologous chondrocyte implantation seems to provide a durable clinical outcome in those patients demonstrating success at 15 months after operation. Comparisons between other outcome measures of autologous chondrocyte implantation should be focused on the clinical status at 15 months after surgery. The patient-reported clinical outcome at 15 months is a major predictor of the mid- to long-term success of autologous chondrocyte implantation.

Efficacy and Safety of Autologous Cell Therapies for Knee Cartilage Defects (Autologous Stem Cells, Chondrocytes or the Two): Randomized Controlled Trial Design

“…MRI, histology, arthroscopy and other outcome scores will be compared using one-way analysis of variance, if available using preoperative values as covariates. For the continuous outcome measures that are collected repeatedly over time (such as the Lysholm knee score), repeated measures analyses will be performed on the change from the baseline score, using standard multilevel modeling techniques [3]. Such analyses have the advantages of being able to combine results from different time-points to maximize power, and also to investigate the precise form of any benefit (whether, for example, any treatment benefit, should one exist, increases or decreases with time).…”

“…The primary outcome measure of the ASCOT trial is the patient-reported knee function (Lysholm score) at 15 months post-treatment, taking into account the preoperative score as a covariate [3]. The Lysholm score is a validated, long-established eight-item questionnaire of knee function.…”

“…A sample size of 38 patients per trial arm (i.e., 114 patients in total) is sufficient to test the two hypotheses with 80% power at p = 0.05, based on detecting the minimal clinically important difference in Lysholm knee scores of 13 points between the groups: an effect size of 0.7-times the standard deviation of 18.5 in baseline Lysholm scores [3,46,47]. The chosen sample size allows a 10% loss to follow-up for various reasons in each arm, a number based on our multicenter trial of ACI versus alternative treatments (ACTIVE).…”

“…The cell suspension is retained by either a patch of periosteum or a commercially available collagen membrane, sutured to the edges of the defect and sealed with fibrin. Our center has used ACI in approximately 500 procedures and we and others have shown that it has the potential to improve functional outcome [2][3][4] and generate repair tissue that offers a durable surface and is well integrated with the surrounding cartilage [5][6][7][8]. In our audits of ACI, 80% of patients improve by 15 months, and this improvement is sustained for 9-16 years [3,9].…”

“…Our center has used ACI in approximately 500 procedures and we and others have shown that it has the potential to improve functional outcome [2][3][4] and generate repair tissue that offers a durable surface and is well integrated with the surrounding cartilage [5][6][7][8]. In our audits of ACI, 80% of patients improve by 15 months, and this improvement is sustained for 9-16 years [3,9]. Some randomized controlled trials reported a significant benefit of ACI or matrix-applied characterized ACI over microfracture [10] whereas others found no evidence for a difference between outcomes of these interventions in a multicenter randomized controlled trial [11].…”