Rehabilitation of the Knee After Autologous Matrix-Induced Chondrogenesis: A Systematic Review of Rehabilitation Protocols and Clinical and Radiological Outcomes

Background: Autologous matrix-induced chondrogenesis (AMIC) is an effective treatment for focal chondral knee lesions. Rehabilitation optimizes the environment for cartilage healing while avoiding deleterious effects to the repair site. Purpose: To evaluate rehabilitation protocols after AMIC and its effect on clinical and radiological outcomes. Study Design: Scoping review; Level of evidence, 4. Methods: Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the authors conducted a systematic search of the PubMed, Embase, Scopus, and Cochrane Library databases on April 30, 2025, using key search terms including “AMIC,”“knee,” and their synonyms. Outcomes assessed included the International Knee Documentation Committee (IKDC) score, visual analog scale (VAS) score, Lysholm score, and magnetic resonance imaging (MRI) findings. Descriptive synthesis of the data from 8 studies was conducted. Results: Eight studies were included, representing 258 patients (259 knees) with isolated AMIC. All chondral lesions were International Cartilage Regeneration & Joint Preservation Society grade 3 or 4 (mean defect size range, 2.6-3.7 cm 2 ). There were 7 and 8 rehabilitation regimens available for condylar and patellofemoral lesions, respectively. Commencement of full weightbearing (FWB) varied from immediately to 10 weeks postoperatively. Four of 7 rehabilitation protocols for condylar lesions utilized progressive weightbearing (starting with partial weightbearing after surgery), permitting FWB at 4 to 10 weeks (mean, 7.5 weeks; median, 8 weeks), unrestricted range of motion (ROM) at 6 weeks (mean and median), jogging at 6 months (mean and median), and sports at 4 to 18 months (mean and median, 11 months) after surgery. Three of the 8 rehabilitation protocols for patellofemoral lesions permitted FWB immediately postoperatively, with unrestricted ROM at 28 to 56 days (mean, 38 days; median, 30 days) and sports at 4 to 6 months (mean and median, 5 months) after surgery. IKDC, VAS, and Lysholm scores and MRI findings generally improved in all studies at follow-up as compared with preoperative scores and MRI findings. Conclusion: This review demonstrated that rehabilitation protocols varied according to the location of the lesion, with a general trend of earlier weightbearing for patellofemoral lesions, in comparison with earlier ROM for condylar lesions. The postoperative clinical outcome and MRI findings are similar with both protocols, suggesting that this approach of customizing the ROM and weightbearing components in the rehabilitation protocol to the lesion site plays a role in the positive outcome.