Accuracy of Partial Weight Bearing After Autologous Chondrocyte Implantation

Ebert JR, Ackland TR, Lloyd DG, Wood DJ. Accuracy of partial weight bearing after autologous chondrocyte implantation.ObjectiveTo determine whether patients can accurately replicate and retain weight-bearing restrictions in both stationary (static) and dynamic conditions after autologous chondrocyte implantation (ACI).DesignCase series.SettingRehabilitation clinic.ParticipantsA consecutive sample of patients (N=48) who had undergone ACI to a medial or lateral femoral condylar defect in the knee.InterventionsPatients were trained to partially weight bear using bathroom scales and forearm crutches prior to assessment.Main Outcome MeasuresA force platform was used to measure peak vertical ground reaction forces in patients during static and dynamic conditions immediately after weight-bearing instruction and training, and again during gait 7 days after training.ResultsImmediately after instruction and weight-bearing practice on a set of scales, patients exerted a mean of 15.8% body weight more than expected during walking for 20% weight-bearing trials, 8.3% more for the 40% trials, 11.9% more for the 60% trials, and 1.2% less for the prescribed 80% trials. Accuracy of weight-bearing replication improved across all weight-bearing levels when assessed 7 days later, when patients exerted a mean of 6.6% body weight more than expected during walking for 20% weight-bearing trials (9.2% body weight improvement), 4.2% more for the 40% trials (4.1% body weight improvement), 9.9% more for the 60% trials (2% body weight improvement), and 0.2% more for the 60% trials (1% body weight improvement).ConclusionsPatients were unable to follow weight-bearing restrictions after instruction and practice on a set of scales, and patients were unable to replicate weight-bearing levels in both static and dynamic conditions.