Matrix-induced autologous chondrocyte implantation (MACI) has demonstrated encouraging outcomes in the treatment of symptomatic knee cartilage defects. However, longer term results are lacking and rehabilitation has traditionally been conservative.
This study sought to investigate long-term outcomes after an accelerated (versus conservative) weight bearing (WB) protocol after MACI.
Between November 2005 and November 2007, 70 patients undergoing MACI were prospectively recruited and randomized to either an accelerated (AR, 8 weeks, n=34) or conservative (CR, 12 weeks, n=36) return to full WB gait. At 10-12 year follow up (range 10.5-11.5 years), 60 patients (86%, AR=31, CR=29) were available for review. Clinical outcomes included the IKDC, KOOS, Lysholm, Cincinnati, Tegner, SF-36, Satisfaction, maximal isokinetic knee extensor and flexor strength and functional hop capacity. High resolution magnetic resonance imaging (MRI) was undertaken to assess pertinent parameters of graft repair, as well as a combined MRI composite score. ANOVA investigated group differecnes over time.
No differences (p>0.05) were observed in patient demographics or injury/surgery characteristics between groups, nor clinical and MRI-based scores. All clinical scores significantly improved (p<0.001) to 5 years, maintained to 10 years. At 10 years post-surgery, a mean Limb Symmetry Index (LSI) was calculated for maximal knee extension strength (AR=96.8%, CR=97.9%), as well as the single (AR=95.5%, CR=98.9%) and triple hop (AR=96.7%, CR=99.6%) for distance, with no differences (p>0.05) between groups. A total of 82.4% and 83.3% of patients in the AR and CR groups, respectively, demonstrated a good-excellent MRI composite score, while 79.4% and 83.3% demonstrated good-excellent tissue infill. Graft failure was observed in 5 patients (8.3%) at 10 years, including 2 AR (6.5%) and 3 CR (10.3%) patients. At 10 years, 93.3% of patients were still satisfied with MACI for relieving their pain, with 83.4% satisfied with their ability to participate in sport, with no differences between groups.
MACI provided high levels of satisfaction and tissue durability beyond 10 years. The AR protocol produced comparable outcomes to the CR, without compromising graft integrity.