Abstract:[Objective] To investigate the clinical consequences of early continuous passive motion (CPM) on the repair of knee carti-lage injury after arthroscopic microfracture. [Methods] A retrospective study was conducted on 79 patients who received arthroscopic mi-crofracture for knee cartilage injury in our hospital from January 2017 to May 2021. According to the results of doctor-patient communica-tion, 40 patients received early CPM treatment, while other 39 cases received routine rehabilitation. The perioperative period, follow-upand imaging documents were compared between the two groups. [Results] There were no significant differences in cartilage injury site, ma-jor lesion area, operation time, incision healing, hospital stay, preoperative and postoperative VAS scores 1 day after surgery between thetwo groups (P>0.05). However, the CPM group were significantly better than the conventional group in term of VAS scores 3 and 7 days af-ter surgery [(5.4±0.9) vs (5.9±0.8), P=0.007; (4.6±1.0) vs (5.2±1.2), P=0.010]. The VAS, OKS, WOMAC , AKS scores and knee ROM signifi-cantly improved in both groups over time (P<0.05). The CPM group proved significantly superior to the routine group in terms of VAS score[(3.9±0.9) vs (4.4±0.6), P=0.004; (2.8±1.0) vs (3.4±0.9), P=0.003], OKS score [(33.8±4.2) vs (40.1±3.7), P<0.001; (25.5±3.4) vs (30.3±3.8),P<0.001], WOMAC score [(16.5±2.9) vs (20.1±3.1), P<0.001; (13.7±3.0) vs (18.2±3.9), P<0.001], AKS score [(96.3±10.5) vs (80.4±9.9), P<0.001; (113.5±13.3) vs (103.8±10.4), P<0.001], knee ROM [(107.1±9.3)° vs (99.0±7.8)°, P<0.001; (111.9±9.0)° vs (105.0±9.1)°, P<0.001]18 weeks postoperatively and the latest follow up. With respect of imaging, MRI grading of cartilage injury in the CPM group was signifi-cantly improved at the last follow-up compared with the preoperative period (P<0.05), but there was no significant change in MRI grade of cartilage injury in routine group (P>0.05). At the last follow-up, the MRI grade of cartilage injury in the CPM group was significantly betterthan that in the routine group [0/I/II/III/IV, (1/7/11/13/8) vs (0/2/8/15/14), P<0.001] . [Conclusion] Early continuous passive motion afterarthroscopic microfracture for knee cartilage injury can greatly improve the clinical symptoms and knee function, with considerable carti-lage repair effect and fewer complications.