Chondral Defect Repair with Particulated Juvenile Cartilage Allograft

Objective: This clinical study was conducted to evaluate a cartilage repair procedure of transplanting particulated juvenile cartilage tissue allograft (DeNovo NT Natural Tissue Graft). Design: A multi-center, prospective, single arm, 25-subject clinical study was designed to evaluate clinical outcomes such as IKDC and KOOS scores, as well as extent and quality of repair with MRI and optional biopsies at various time points postimplantation (up to five years). To date, 19 patients with one or two chondral lesions on the femoral condyles and/or trochlea have been treated with this cartilage repair technique. Results: The first group of nine patients has been evaluated with up to 18 months post-op follow-up. No revision has been performed to date. Significant improvements in clinical outcomes over the pre-op baseline data have been observed. MRI data at 12 months post-implantation indicated good defect filling. Conclusions: The present report describes clinical data of a cartilage repair procedure of transplanting particulated juvenile cartilage tissue allograft to treat cartilage lesions of femoral condyles and trochlea. Clinical outcome data as measured at up to 18 months post-implantation and MRI data indicate early positive outcome of this technique. Chondral Defect Repair with Particulated Juvenile Cartilage Allograft There was also a study where autologous osteochondral graft was turned into paste and the resulting material was implanted to repair cartilage defect, which was concomitantly treated with microfracture. Animal studies showed that the combination of bone and cartilage in a paste formed bone and cartilage while cartilage pieces alone formed cartilage. Furthermore, animal studies in the SCID mouse, goat and horse models showed that particulated adult cartilage grafts can remodel to form a continuous volume of repair tissue. Independent studies showed that new extracellular matrix can be formed between two adjacent juvenile cartilage cubes in an explants culture study (Fig. 1) and particulated juvenile cartilage grafts healed chondral defects on trochlea areas of the horse knee joints (Fig. 2). In parallel with this particulated cartilage research, there have been studies evaluating the effect of age on cartilage healing. These studies demonstrated that injured immature cartilage can heal spontaneously while injured adult cartilage cannot heal. Furthermore, marked differences in biological responses between juvenile and adult cartilage have been found, which suggest that transplantation of juvenile chondrocytes could potentially lead to improved cartilage defect healing: • Immature articular cartilage tissue has a significantly higher cell density than mature articular cartilage. • Immature chondrocytes are superior at producing extracellular matrix than mature chondrocytes as measured by the rate of production of sulfated glycosaminoglycan (S-GAG). • Immature chondrocytes show significantly greater mRNA levels for Type II and Type IX collagen. The present paper will detail the results to date of an IRB approved prospective study of particulated juvenile cartilage allograft (DeNovo NT Natural Tissue Graft) (Zimmer, Inc., Warsaw, IN/ISTO Technologies, Inc., St. Louis, MO) transplanted in human knees, with a subset of patients Fig 2. Chondral repair with particulated juvenile cartilage tissue in an equine model. (Data on file at ISTO Technologies, Inc., St. Louis, MO) Fig 1. The in vitro extracellular matrix outgrowth of particulated juvenile cartilage tissue. (Data on file at ISTO Technologies, Inc., St. Louis, MO) currently at 18 months after surgery. The objective of this clinical study was to evaluate clinical performance of this cartilage repair technique.