## 3 Results
Their authors confirmed a positive effect of the microfracture technique in reducing pain and improving knee function. [PERSON] et al. [37] included 58 patients out of whom a vast majority had grade IV or III cartilage lesions. They have shown good pain relief and improvement in the function of the knee after one year. Degenerative changes treatment was also studied in the ankle joint, where it was also shown that the microfracture technique gives good outcomes as far as the pain relief and function improvement are considered [38]. The effect of microfractures was investigated in detail in regard to histologic and mechanical properties of the regenerative cartilage. It was shown that mechanical properties of the regenerative cartilage after isolated microfractures are inferior to the regenerative cartilage after augmentation of the procedure with PRP intraarticular administration [17; 28]. The greatest improvements in the knee function and decline in pain were reported in the first 6 weeks in the PRP group, as opposed to the control group, where the improvement was observed after 12 weeks. Our results are consistent with other authors suggesting that microfractures give a quick improvement of the knee function; however, PRP augmentation may accelerate the therapeutic effect. Most of the authors noted the greatest improvement in the first few weeks, after which the improvement was in plateau stage [37; 38; 39] for the follow-up time, which is consistent with our findings for the PRP group. In the past, the microfracture technique was mostly used in younger population in focal cartilage defects. However, with the use of PRP, it might be theoretically applicable in older population. There is a limited number of papers concerning the use of the microfracture technique in older population. In our study we have shown that microfracture with or without PRP is a considerable alternative for patients after 60 years of age. In the study conducted by [PERSON] et al. [37], the mean age was also over 60, and the results were comparable with our findings. In a large study [40], where over 29,000 of MFx procedures were evaluated, the two-year revision surgery rate was calculated as 14.65%. Given fast improvement in function and pain relief and less than 15% revision rate after MFx, the procedure seems to be promising in early stages of OA even in older populations, as was shown in our study. Moreover, arthroscopy prior to total knee replacement was shown by [PERSON] et al. [41; 42] to have no effect on the survival rate of TKA. Encouraging results of in vitro and animal studies on chondral tissue with the use of PRP [11; 23; 28; 43] have been published in the past. In our study, we found that PRP administration accelerates and prolongs the therapeutic effect. The control and PRP groups showed clinical improvement over the course of six weeks, which lasted to the end of the follow-up in the PRP group. Overall, WOMAC score in the control group at the end of the follow-up did not show a significant difference in regard to the preoperative score, which could suggest that PRP has an effect on prolonging clinical effects of treatment. Other studies concerning PRP usage in augmentation of MFx had a follow-up of 24 months, at the end of which the results in pain reduction and function improvement were comparable [37; 39; 44]. The main limitation of the study was the small size of the study group, which was enforced by study funding. The number of participants in the study group could have an impact on overall statistical results of the study; however, the study group is comparable with papers published in the last few years on this subject [44; 45; 46]. Another limitation of the study is a high deviation of baseline WOMAC and Lysholm scores among participants, which is nonetheless typical of early OA manifestations in affected patients. Base line deviation could also influence Lysholm scores if the patients changed their activity levels during study.