Transplant of mesenchymal stem cells and hydroxyapatite ceramics to treat severe osteochondral damage after septic arthritis of the knee.

We describe a 21-year-old man with a large osteochondral defect of the knee after septic arthritis, successfully treated by transplant of mesenchymal stem cells (MSC) from bone marrow and a new type of interconnected porous hydroxyapatite ceramic (IP-CHA). We confirmed successful cartilage-like tissue regeneration by a second arthroscopy. Biopsy of the repaired tissue revealed cartilage-like regeneration and bone formation. We were able to regenerate new bone and cartilage-like tissue in a one-stage operation, without sacrificing autologous bone or other tissue. This cultured MSC and IP-CHA hybrid material transplant represents a novel treatment for a severe osteochondral defect after septic arthritis.