When a joint is injured as a result of a joint sprain or fracture, there can be damage done to the layer of cartilage just above the joint surface. These are called osteochondral or chondral lesions and they occur in up to half of all ankle injuries. Surgical transplantation techniques to repair the cartilage have been developed and improved over the last 10 years.
In this review article, surgeons from the Hospital for Special Surgery in New York City bring us up-to-date on arthroscopic bone marrow stimulation, tissue transplantation, and the newer cell-based and biologic techniques for cartilage repair. The focus is on the treatment of osteochondral lesions of the talus. The talus is a bone in the ankle situated between the tibia (larger of the two lower leg bones) and the calcaneus (heel bone).
Ankle injuries severe enough to damage the cartilage are common in sports athletes. Treatment is designed to restore the cartilage and give the athletes relief from painful symptoms. The final goal is to get them back into action at a level equal to (or even better) than before the injury. How well each of these techniques meets these goals is also reviewed (based on current outcomes reported in the literature).
Starting with bone marrow stimulation (e.g., microfracture, drilling of the subchondral plate) the authors provide a rationale for the treatment, description (drawings, CT scans), and currently reported results. Limitations of the procedure are also mentioned.
They do the same thing for autologous osteochondral transplantation (replacement of the defect with a tubular unit of donor hyaline cartilage and bone taken from the patient’s knee) and osteochondral allograft transplantation (replacement of large defect from a donor other than the patient).
The more complex, two-stage autologous chondrocyte implantation is discussed separately. There are two different ways to accomplish this technique: periosteum-covered technique and matrix-associated technique. Both involve removing good, healthy chondrocytes (cartilage cells), taking them to the lab and making more chondrocytes, and then reimplanting the cells into the lesion (defect or hole in the cartilage). The matrix-associated technique is not currently available in the United States.
You have probably heard about stem cell research. The use of stem cells (taken from the patient’s own bone marrow) and then injected into the osteochondral lesion is under investigation. Early studies (with animals) are underway now but no conclusions have been reached yet regarding results.
And finally, one last biologic treatment to repair cartilage is with the use of hyaluronic acid. Hyaluronic acid is a substance normally contained within the joint (synovial) fluid. It helps keep the joint surfaces moving smoothly.
Hyaluronic acid injections into the joint have been done after microfracture and compared with patients who had microfracture without the hyaluronic acid injections. Outcomes with a limited number of patients show that results are much improved in the microfracture plus hyaluronic acid injection group over the microfracture-only group.
As you might expect, there is a need to compare all of these approaches to see which one works best for different groups of patients. Outcomes of well-designed studies with carefully selected patients will go a long way in guiding future treatment plans for osteochondral lesions of the talus.