*3.3. Efficacy Assessment*

We applied IKDC subjective knee evaluation criteria to evaluate the knee function before and after the treatments. Figure 1 showed a tendency that the IKDC scores continuously improved in the Kartigen® group, but the control group achieved the highest IKDC score in the 28th week and gradually decreased. In the study group, the IKDC score before Kartigen® implantation was 47.1 <sup>±</sup> 17.0 (mean <sup>±</sup> standard deviation) and then significantly improved to 62.1 ± 12.8 (*p*-value = 0.025) 16 weeks after implantation. The IKDC scores continuously increased to 78.2 ± 15.4 with a statistical significance (*p*-value < 0.005) one year after the operation and still maintained at 73.6 ± 13.8 2 years after the operation. While IKDC scores slightly decreased in the second year, the scores were still significantly higher than that of preoperation (*p*-value < 0.005). Meanwhile, although the control group demonstrated significantly improved IKDC scores from 54.0 ± 9.1 (preoperation) to 68.5 ± 6.1 (28 weeks after the operation) with a *p*-value of 0.032, the score decreased to 63.5 ± 11.6 1 year after the operation and to 52.6 ± 16.4 2 years after the operation. The comparison of IKDC scores between the Kartigen® group and the microfracture group in the second year exhibited statistical significance with the *p*-value of 0.029. Still, a longer follow-up will be needed to evaluate the long-term efficacy and longevity of the regenerated cartilage.

The VAS was used to measure the pain before and after treatments. Both the Kartigen® implantation and microfracture treatment effectively achieved pain relief at the 10th week after the operation (Figure 2). However, the Kartigen® implantation exhibited consistent pain relief through the 1-year follow-up, which was validated statistically using Wilcoxon signed-rank test with *p*-values < 0.005.
