Long term in-vivo studies of a photo-oxidized bovine osteochondral transplant in sheep

BACKGROUND: Articular cartilage has limited capacity to repair. Defects greater than 3 mm heal with formation of inferior fibrous cartilage. Therefore, many attempts have been made to find the ideal graft for larger cartilage lesions. Different grafts, such as untreated or cryopreserved osteochondral transplants, have been used with variable success. METHODS: Photo-oxidized osteochondral grafts were implanted in both femoral condyles of one ovine knee. Untreated xenogeneic and autogeneic grafts served as controls. Three groups of 8 sheep each were formed and they were sacrificed 6, 12 or 18 months after surgery. RESULTS: The macroscopic evaluation of the condyle and graft showed a well-maintained cartilage surface in most grafts at all time points. However, the host cartilage matrix deteriorated considerably in all xenogeneic, most autogeneic and fewer of the photo-oxidized grafts at 12 and 18 months, respectively. The blue colour of the photo-oxidized grafts resulting from the process of photo-oxidation was visible in all grafts at 6 months, had diminished at 12 months and had completely disappeared at 18 months after surgery. Histologically a loss of matrix staining was almost never noticed in untreated xenografts, transiently at 6 months in photo-oxidized grafts and increased at 12 and 18 months. Fusion between graft and host cartilage could be seen in photo-oxidized grafts at 12 and 18 months, but was never seen in autografts and xenografts. CONCLUSIONS: The photo-oxidation of osteochondral grafts and its use as transplant appears to have a beneficial effect on cartilage and bone remodelling. Osteochondral grafts pre-treated with photo-oxidation may be considered for articular cartilage replacement and therefore may delay artificial joint replacements in human patients

Fixation with autogenous osteochondral grafts for the treatment of osteochondritis dissecans (stages III and IV)

This paper presents a clinical and functional assessment of the cases of osteochondritis dissecans (OCD) treated with small mosaicplasty type osteochondral grafts. Between 1999 and 2004, we operated on 12 knees with OCD stages III and IV. They were assessed using the International Cartilage Research Society (ICRS) scale, the Visual Analogue Scale (VAS) scale, X-ray and magnetic resonance imaging (MRI). The study was carried out using a clinical series, was retrospective and had a level of evidence of 4. Before surgery, all patients were in classes III and IV on the ICRS scale (four in class III and eight in class IV). At the time of surgery, the patient age was 27.5 ± 7.9 years, with male predominance (75%). Eleven of the cases were assessed as classes I and II on the ICRS scale (seven in class I and four in class II), with one patient in class IV. X-ray assessment was less favourable, revealing alterations in the articular space in 75% of cases. The results show that this technique enables the biological fixation of fragments and, functionally, the clinical results obtained were very good. The osteochondral grafts avoid the implantation of foreign material and make use of bone fragments of the same rigidity as the OCD fragment. We conclude that the technique described is an excellent alternative to the techniques normally used for the fixation of stage III and IV OCD