Defects that had prior treatment affecting the subchondral bone failed at a rate 3 times that of nontreated defects. The failure rates for drilling (28%), abrasion arthroplasty (27%), and microfracture (20%) were not significantly different, possibly because of the lower number of microfracture patients in this cohort (25 of 110 marrow-stimulation procedures). The data demonstrate that marrow stimulation techniques have a strong negative effect on subsequent cartilage repair with autologous chondrocyte implantation and therefore should be used judiciously in larger cartilage defects that could require future treatment with autologous chondrocyte implantation.

Young patients with early osteoarthritis wishing to remain functionally active have limited treatment options. Existing studies examining the use of autologous chondrocyte implantation (ACI) have included patients with early degenerative changes; however, none specifically investigated the outcome of ACI with this challenging problem. We prospectively followed 153 patients (155 knees) for up to 11 years after treatment with ACI for early-stage osteoarthritis.

Our results showed a failure rate of ACI in older patients that is comparable with rates reported in younger patient groups. The procedure is associated with a substantial rate of reoperations, mostly for the arthroscopic treatment of graft hypertrophy, similar to that in younger patients.