Allograft Osteoarticular Transfer
Articular cartilage is a white, glistening tissue that surfaces the ends of the bone in a joint. Full-thickness cartilage defects may occur on the end of the thigh bone (femur), upper end of the shin bone (tibia) or kneecap (patella), most often following trauma or injury to the knee. This specialized surface, which is smooth, firm, and resilient, has relatively little ability to repair or regenerate itself. When the size of the cartilage defect is too large for an autograft (tissue from your own knee) and too large to reimplant cultured cells from your own knee, a composite of bone and attached cartilage from a cadaver donor may be the most appropriate option. Patients under 50 years of age are best suited for this procedure. The composite of bone and cartilage is harvested in sterile fashion as a block from the cadaver donor. Every effort is made to preserve the viability of the cartilage tissue. The donor specimen is tested for diseases that could be transmitted. During surgery, your cartilage defect size is mapped and the donor graft carefully shaped to match the lesion. The bone and cartilage plug is then press fit into the recipient socket carefully recreating the normal contour of the cartilage surface in your knee. The bone heals into the prepared socket much like a fracture and provides a stable support for the overlying cartilage. Protected weight bearing is necessary for a period of 8 weeks as the transferred bone begins to heal. Physical therapy is employed to assist you in regaining range-of-motion and leg strength. Full recovery for unrestricted activities is typically 8 – 9 months. There is an approximately 80 – 85% success of incorporation of the graft into the host bone.