Enhanced microfracture using acellular scaffolds improves results after treatment of symptomatic focal grade III/IV knee cartilage lesions but current clinical evidence does not allow unequivocal recommendation

Purpose To systematically analyse post-operative outcomes following enhanced microfracture procedures in focal cartilage injuries of the knee. Methods Database searches were conducted in PubMed, EMBASE and Cochrane Library databases up to 30 November 2018, for clinical studies in humans that assessed surgical outcomes of enhanced microfracture procedures in focal cartilage injuries of the knee. The clinical, functional and imaging outcomes were assessed and summarized. The MINORS scale was used to assess the methodological quality of the studies included. Results Ten studies were included comprising a total of 331 patients (mean age of 37.0 +/- 5.5 years, body mass 25.2 +/- 1.7 kg m(2), 56% male and 42% left knee), 278 femoral condyle chondral defects (147 medial, 35 lateral and 78 undefined) and 43 chondral defects distributed by the tibial plateau, patella and femoral trochlea. The chondral defects were mostly Outerbridge grade III or IV and the mean defect size was 3.2 +/- 0.6 cm(2). Studies consistently demonstrated significant improvement in the patient-reported outcome measures from baseline to final follow-up. Overall, imaging outcomes showed inconsistent results. Treatment-related adverse events were poorly reported. Conclusion Enhanced microfracture techniques significantly result in improved patient-reported outcome measures over the MCID, but provide inconsistent imaging results. Current clinical evidence does not allow for unequivocal recommendation of enhanced microfracture to treat symptomatic focal grade III/IV knee cartilage lesions.