Morphologic and biochemical study of sternal cartilage autografts for resurfacing induced osteochondral defects in horses

Anne M. Vachon From the Department of Clinical Sciences (Vachon, McIlwraith) and Radiation Biology (Powers), College of Veterinary Medicine and Biomedical Sciences, Colorado State Univeristy, Fort Collins, CO 80523, and Department of Surgery, Division of Orthopaedics (McFadden, Amiel), School of Medicine, University of California, San Diego, CA 92103.

Search for other papers by Anne M. Vachon in
Current site
Google Scholar
PubMed
Close
 DVM, PhD;
,
C. Wayne McIlwraith From the Department of Clinical Sciences (Vachon, McIlwraith) and Radiation Biology (Powers), College of Veterinary Medicine and Biomedical Sciences, Colorado State Univeristy, Fort Collins, CO 80523, and Department of Surgery, Division of Orthopaedics (McFadden, Amiel), School of Medicine, University of California, San Diego, CA 92103.

Search for other papers by C. Wayne McIlwraith in
Current site
Google Scholar
PubMed
Close
 BVSc, PhD
,
Barbara E. Powers From the Department of Clinical Sciences (Vachon, McIlwraith) and Radiation Biology (Powers), College of Veterinary Medicine and Biomedical Sciences, Colorado State Univeristy, Fort Collins, CO 80523, and Department of Surgery, Division of Orthopaedics (McFadden, Amiel), School of Medicine, University of California, San Diego, CA 92103.

Search for other papers by Barbara E. Powers in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Paul R. McFadden From the Department of Clinical Sciences (Vachon, McIlwraith) and Radiation Biology (Powers), College of Veterinary Medicine and Biomedical Sciences, Colorado State Univeristy, Fort Collins, CO 80523, and Department of Surgery, Division of Orthopaedics (McFadden, Amiel), School of Medicine, University of California, San Diego, CA 92103.

Search for other papers by Paul R. McFadden in
Current site
Google Scholar
PubMed
Close
 BA
, and
David Amiel From the Department of Clinical Sciences (Vachon, McIlwraith) and Radiation Biology (Powers), College of Veterinary Medicine and Biomedical Sciences, Colorado State Univeristy, Fort Collins, CO 80523, and Department of Surgery, Division of Orthopaedics (McFadden, Amiel), School of Medicine, University of California, San Diego, CA 92103.

Search for other papers by David Amiel in
Current site
Google Scholar
PubMed
Close
 Dip Ing

Summary

Using biodegradable pins, sternal cartilage autografts were fixed into osteochondral defects of the distal radial carpal bone in ten 2 to 3-year-old horses. The defects measured 1 cm2 at the surface and were 4 mm deep. Control osteochondral defects of contralateral carpi were not grafted. After confinement for 7 weeks, horses were walked 1 hour daily on a walker for an additional 9 weeks. Horses were euthanatized at 16 weeks. Half of the repair tissue was processed for histologic and histochemical (H&E and safranin-O fast green) examinations. The other half was used for the following biochemical analyses: type-I and type-II collagen contents, total glycosaminoglycan content, and galactosamine-to-glucosamine ratio. On histologic examination, the repair tissue in the grafted defects consisted of hyaline-like cartilage. Repair tissue in the nongrafted defects consisted of fibrocartilaginous tissue, with fibrous tissue in surface layers. On biochemical analysis, repair tissue of grafted defects was composed predominantly of type-II collagen; repair tissue of nongrafted defects was composed of type-I collagen. Total glycosaminoglycan content of repair tissue of grafted defects was similar to that of normal articular cartilage. Total glycosaminoglycan content of nongrafted defects was 62% of that of normal articular cartilage (P < 0.05). Repair tissue of all defects was characterized by galactosamine-to-glucosamine ratio significantly (P < 0.05) higher than that of normal articular cartilage. These results at 16 weeks after grafting indicate that sternal cartilage may potentially constitute a suitable substitute for articular cartilage in large osteochondral defects of horses.

Summary

Using biodegradable pins, sternal cartilage autografts were fixed into osteochondral defects of the distal radial carpal bone in ten 2 to 3-year-old horses. The defects measured 1 cm2 at the surface and were 4 mm deep. Control osteochondral defects of contralateral carpi were not grafted. After confinement for 7 weeks, horses were walked 1 hour daily on a walker for an additional 9 weeks. Horses were euthanatized at 16 weeks. Half of the repair tissue was processed for histologic and histochemical (H&E and safranin-O fast green) examinations. The other half was used for the following biochemical analyses: type-I and type-II collagen contents, total glycosaminoglycan content, and galactosamine-to-glucosamine ratio. On histologic examination, the repair tissue in the grafted defects consisted of hyaline-like cartilage. Repair tissue in the nongrafted defects consisted of fibrocartilaginous tissue, with fibrous tissue in surface layers. On biochemical analysis, repair tissue of grafted defects was composed predominantly of type-II collagen; repair tissue of nongrafted defects was composed of type-I collagen. Total glycosaminoglycan content of repair tissue of grafted defects was similar to that of normal articular cartilage. Total glycosaminoglycan content of nongrafted defects was 62% of that of normal articular cartilage (P < 0.05). Repair tissue of all defects was characterized by galactosamine-to-glucosamine ratio significantly (P < 0.05) higher than that of normal articular cartilage. These results at 16 weeks after grafting indicate that sternal cartilage may potentially constitute a suitable substitute for articular cartilage in large osteochondral defects of horses.

Advertisement