Evaluation of Scaffold Fixation for Treatment of Osteochondral Defects of the Knee

Articular cartilage damage is a common source of knee pain that can be treated with autologous chondrocyte implantation (ACI). Fixation of the scaffolds can be accomplished by various means with bone sutures being the most effective. The purpose of this study was to evaluate the fixation of a new scaffold with three bone sutures after cycling with continuous passive motion (CPM). Two defects, each of 20mm diameter and 5mm depth, were created per knee and the scaffold was fixed with three bone sutures at the 12 o’clock, 4 o’clock and 8 o’clock positions. Knees were then cycled from 0 degrees to 74 degrees to 0 degrees on a CPM machine for a total of 210 cycles and the scaffolds were then evaluated for fixation, fraying and delaminations. All scaffolds were noted to have remained fixed inside the defect. Fraying occurred in 16 out of the 20 scaffolds and delaminations occurred in 12 out of the 20. Only two scaffolds were completely free of both fraying and delaminations. Fraying occurred in 32.5% of the circumference of medial scaffolds while only 15.0% in lateral scaffolds. Fraying occurred mostly over flush areas and the least over recessed areas. Overall, three bone sutures provided excellent fixation of this scaffold. If at all possible, the scaffold should be recessed into the defect to minimize the amount of fraying that occurs.