Five-Year Outcome of Characterized Chondrocyte Implantation Versus Microfacture for Symptomatic Cartilage Defects of the Knee: Early Treatment Matters

Vanlauwe J, Saris DBF, Victor J, Almqvist KF, Bellemans J, Luyten FP, & TIG/ACL Study Group. American Journal of Sports Medicine. 2011;39(12): 2566-2574. 

Structural changes that occur when there is an articular cartilage defect in the knee are associated with pain, swelling, and functional limitations.  Many treatment strategies involve symptomatic control until surgical intervention is necessary.  Surgery aims to restore structure to try to prevent the long-term likelihood of developing osteoarthritis.  The purpose of this randomized trial was to compare 5-year clinical outcomes between patients undergoing microfracture (MF; drilling into the subchondral bone to promote fibrosis into the lesion area) and characterized chondrocyte implantation (CCI; harvesting and growing of patient’s cartilage that is then placed into patch over lesion area) surgical techniques for femoral condyle articular cartilage defects.  A total of 118 patients (18 to 50 years old) were randomized to receive either microfracture (n = 61) or characterized chondrocyte implantation (n = 57) for their cartilage defect.  Patient outcomes were followed for approximately 60 months and evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS), a visual analog scale, physical examination, adverse events, and radiographs.  Optimal KOOS scores occurred around 12 months for MF, and around 24 months for CCI.  In regards to the KOOS, the only statistical difference between groups was found at 36 months post surgery, however, there was an overall trend of better KOOS scores in the CCI group throughout all time points.  At 60 months post surgery, no differences were found between surgical groups in improvement in overall KOOS.  Subgroup analyses conducted on symptom onset prior to surgery (< 3 years versus ≥ 3 years) revealed that CCI demonstrated better improvements than MF at 3 time points, including 60 months, among patients with symptom onset of < 3 years.  Among patients with symptoms onset ≥ 3 years prior to surgery there were no significant differences between techniques.  Another subgroup analysis was conducted on age (< 35 years versus ≥ 35 years) and demonstrated no differences in outcomes between surgical techniques.

This study demonstrates that both surgical techniques have favorable outcomes up to 5 years post-surgery.  Maximum KOOS scores were achieved earlier in MF than CCI groups, with CCI trending towards having better overall outcomes.  This may have clinical implications based on goals of return to play.  It would be interesting to know the return-to-activity criteria for these groups of patients. The authors also post an interesting point regarding the biochemical environment.  In the case of chronic lesions (e.g., symptom onset > 3 years prior to surgery) the lack of joint homeostasis may impede healing of the articular cartilage. Current clinical practice seems to center around symptomatic relief until surgery is necessary.  This study suggests that once surgery is necessary, there are relatively favorable outcomes, regardless of age.  However, patients who have symptoms onset of less 3 years appear to have better and more consistent outcomes with CCI.  This may emphasize the fact that early intervention may be critical for these types of procedures but it will be important to see more comparisons between those with long-term symptoms prior to surgery and those with a shorter duration between onset of symptoms and surgery.  The longer that a patient waits to repair the cartilage lesion, the longer the remaining cartilage must support the abnormally redistributed load, ultimately leading to degradation and failure of the surrounding cartilage as well as a potential loss in joint homeostasis.  The initial local injury will eventually cause failure of the surrounding joint. A good analogy might be that we don’t wait for symptoms to resolve before we stitch a skin laceration, instead we attempt to repair the tissue while the injury is acute (before the edge of the skin becomes necrotic/compromised).  Does anyone have any experiences with patients/athletes getting either of these surgeries? 

Written by: Nicole Cattano
Reviewed by: Jeffrey Driban

Vanlauwe J, Saris DB, Victor J, Almqvist KF, Bellemans J, Luyten FP, & TIG/ACT/01/2000&EXT Study Group (2011). Five-year outcome of characterized chondrocyte implantation versus microfracture for symptomatic cartilage defects of the knee: early treatment matters. The American Journal of Sports Medicine, 39 (12), 2566-74 PMID: 21908720