KS29: INCREASED FAILURE RATE OF ACI AFTER MARROW STIMULATION

Abstract

Marrow stimulation techniques such as drilling or microfracture are first-line treatment options for symptomatic cartilage defects. Common knowledge holds that these treatments do not compromise subsequent cartilage repair procedures with autologous chondrocyte implantation (ACI). We present our experience with ACI after prior marrow stimulation. This study reviewed prospectively collected data for the first 321 consecutive patients treated at our institution with ACI for full-thickness cartilage defects that have reached more than 2 years of follow-up. Patients were grouped based on whether they had undergone prior treatment with a marrow stimulation technique. Outcomes were classified as complete failure if more than 25% of a grafted defect area had to be removed in later procedures due to persistent symptoms. This includes treatment with revision ACI, allograft transplantation, partial or total knee replacement. 522 defects in 321 patients (325 joints) were treated with ACI. Patient average age was 35 (13–60), there were 185 men and 136 women, with a follow-up of 2–12 Years. On average, there were 1.7 lesions per patient (range, 1–5) with a transplant area of 4.8 cm2 per lesion and 8.1 cm2 per knee. 111 of these joints had previously undergone surgery that penetrated the subchondral bone: microfracture (n=25), abrasion chondroplasty (n=33), and drilling (n=53). 214 joints had no prior treatment that affected the subchondral bone and served as control. Within the marrow stimulation group, there were 27 (24%) failures compared with 17 (8%) failures in the control group. In our review of 321 patients, defects that had prior treatment affecting the subchondral bone failed at a rate 3 times that of non-treated defects. These data demonstrate that marrow stimulation techniques have a strong negative effect on subsequent cartilage repair, and should be used judiciously in larger cartilage defects that could require future treatment with ACI.