Effect of Accelerated Weightbearing after Matrix-Associated Autologous Chondrocyte Implantation on the Femoral Condyle on Radiographic and Clinical Outcome after 2 Years: A Prospective, Randomized Controlled Pilot Study

Background There is no consensus about the optimal time for weightbearing activities after matrix-associated autologous chon-drocyte implantation (MACI) of the femoral condyle. Hypothesis A comprehensive protocol after MACI on the femoral condyle with accelerated weightbearing leads to a better functional and radiographic outcome compared with the same comprehensive protocol with delayed weightbearing. Study Design Randomized controlled trial; Level of evidence, 1. Methods Thirty-one patients (22 male, 9 female) after MACI on the femoral condyle were randomly assigned to the accelerated weightbearing group (group A) or the delayed weightbearing group (group B). Aside from increase and time of full weightbearing, both groups adhered to the same rehabilitation protocol and exercises. Patients were assessed preoperatively and at 4, 12, 24, 52, and 104 weeks after surgery. Clinical evaluation was performed by determining the subjective form of the International Knee Documentation Committee (IKDC), the Tegner activity scale, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Radiological outcome was evaluated by the MOCART score and the size and amount of bone marrow edema and effusion. Results In both groups, there were no differences with regard to the clinical outcome. For the radiological outcome, group A showed a higher prevalence of bone marrow edema after 6 months without correlation to the clinical outcome (P 5 .06-.1). However, after 104 weeks, there were no differences in the radiological outcome between group A and group B. Conclusion A rehabilitation protocol with accelerated weightbearing leads to good clinical and functional outcome after 2 years without jeopardizing the healing graft.