ObjectiveTo explore the effectiveness of arthroscopic microfracture combined with osteochondral autologous transplantation (OAT) in treatment of large area (4-6 cm2) cartilage injury of the femoral condyle of knee.MethodsBetween March 2016 and June 2017, 22 patients of large area cartilage injury of the femoral condyle of knee were treated with arthroscopic microfracture combined with OAT. There were 16 males and 6 females with an average age of 22-60 years (mean, 38.6 years). The cause of injury was traffic accident in 8 cases and sports injuries in 14 cases. The disease duration was 1-6 months (mean, 3.4 months). There were 15 cases of medial femoral condyle injuries and 7 cases of lateral condyle injuries. The area of cartilage defect was 4-6 cm2 (mean, 4.98 cm2). According to the International Cartilage Repair Society (ICRS) classification, 9 cases were rated as grade Ⅲ and 13 cases as grade Ⅳ. Eighteen cases were combined with meniscus injuries. Preoperative visual analogue scale (VAS) score was 6.36±1.25 and Lysholm score was 36.00±7.77.ResultsAll incisions healed by first intention. All patients were followed up 2-3 years with an average of 2.3 years. At 2 years after operation, the VAS score was 1.27±0.94 and the Lysholm score was 77.82±6.21, which were significantly improved when compared with those before operation (t=16.595, P=0.000; t=21.895, P=0.000). At 2 years after operation, MRI showed that the cartilage defect was repaired well.ConclusionArthroscopic microfracture combined with OAT can be used to treat large area cartilage injury of the femoral condyle of knee, and the good early effectiveness can be obtained.