In vivo evaluation of autologous cartilage fragment-loaded scaffolds implanted into equine articular defects and compared with autologous chondrocyte implantation.

Abstract

Current autologous chondrocyte implantation (ACI) techniques require 2 surgical procedures: 1 for cell harvest and 1 for reimplantation of cultured cells. A 1-step procedure is more desirable. A 1-step surgical procedure using autologous cartilage fragments on a polydioxanone scaffold, or CAIS (cartilage autograft implantation system), in a clinically relevant defect (15-mm diameter) within equine femoral trochlea was compared with a 2-step ACI technique as well as with empty defects and defects with polydioxanone foam scaffolds alone. Controlled laboratory study. Ten skeletally mature horses were used. Articular cartilage from the lateral trochlea of the femur was harvested arthroscopically (n = 5), and chondrocytes were cultured on small intestinal submucosa to produce ACI constructs. The CAIS procedure had cartilage harvested during defect creation to prepare minced cartilage on polydioxanone-reinforced foam. The ACI and CAIS constructs were placed in defects using polydioxanone/polyglycolic acid staples. Defects were examined arthroscopically at 4, 8, and 12 months and with gross, histological, and immunohistochemical examination at 12 months. Arthroscopic, histologic, and immunohistochemistry results show superiority of both implantation techniques (ACI and CAIS) compared with empty defects and defects with polydioxanone foam alone, with CAIS having the highest score. This is the first demonstration of long-term healing with strenuous exercise using ACI and CAIS in a critically sized defect. Given these results with the CAIS procedure, testing in human patients is the next logical step (a phase 1 human clinical study has proceeded from this work).