Holes or defects in the surface of a joint that extend down through the cartilage to the bone are called osteochondral lesions. Various treatment approaches have been tried for this problem with some success. One particularly challenging area of the body to treat these defects is the talus bone of the ankle.
The very complex ankle joint with its many bones makes it difficult to reach areas of osteochondral lesions. The talus is one of those problem areas. It is sandwiched in between the calcaneus (heel bone) and the tibia-fibula bones of the lower leg.
The tibia (larger bone of the lower leg) sits over the top of the talus and extends down along one side of the talus creating an area referred to as the talus shoulder. Repairing osteochondral lesions of the talar shoulder is the topic of this study.
Damaged cartilage in older adults doesn't make new chondrocytes (cartilage cells) and can't seem to repair itself. Therefore, the use of bone graft material has been studied as one possible treatment approach. As this study shows, using fresh bone graft placed into the defects along the talar shoulder seems to have good results.
Fresh allografts (taken from a donor rather than harvested from the patient) can be used as soon as they are released by the bone bank that prepares them for use. Most of the time, there is an average delay of almost a month before donor bone is available. Sometimes delays in implanting the bone graft are related more to the surgeon's schedule, availability of an operating room, or health, travel, or work schedule of the patient.
The defect must be large enough to warrant this type of treatment but not so large that a bone replacement is required. The shape of the talar shoulder makes it unlikely that bone plugs inserted into the holes will work -- there just isn't enough structural support for this approach.
Results of the treatment are measured using patient pain levels, function, and imaging studies (X-ray, CT scans, MRIs showing changes in the bone). For the eight patients in this study, results were good-to-excellent without fragmentation, absorption, or rejection of the donor bone. Pain levels were significantly reduced and function significantly improved.
There were no graft failures and no cases of the defect filling in with fibrous scar tissue instead of bone. The surgeons cleaned the donor bone carefully before putting it in the defect as a precaution against disease transmission (e.g., hepatitis or HIV). There were no cases of disease transmission in these eight patients.
Half of the patients did end up having another surgical procedure later. But in all cases, treating osteochondral lesions of the talar shoulder with fresh allograft delayed the need for ankle replacement or fusion. The use of talar allograft transplantation can also be done more than once before considering other more invasive or permanent procedures.
Reference: Samuel B. Adams, Jr, MD, et al. Midterm Results of Osteochondral Lesions of the Talar Shoulder Treated with Fresh Osteochondral Allograft Transplantation. In The Journal of Bone and Joint Surgery. April 2011. Vol. 93. No. 7. Pp. 648-654.