Ankle sprains and other significant trauma (e.g., bone fractures) can cause a condition known as osteochondral lesions. These are defects or “holes” in the cartilage lining a joint. Sometimes the damage is enough to create a hole all the way down into the bone. Since cartilage does not heal well on its own, this type of damage is permanent. Painful clicking and loss of motion and loss of function with early arthritis are likely.
Treatment for osteochondral lesions is the subject of much debate and research around the world. In this study, surgeons from the Rizzoli Orthopaedic Institute in Italy presented a new approach to the problem. The new technique is a one-step stem cell transplantation. The procedure is done arthroscopically, which eliminates the need for a more invasive open incision surgery.
Stem cells are basic building blocks of all cells. They have the ability to transform into all other cells including cartilage (chondral) cells. Once implanted into the defect, they can regenerate the hyaline cartilage that lines the joint surface (right next to the bone).
Forty-nine patients participated in the study. Stem cells were removed from the patients’ own pelvis (iliac crest) by inserting a needle into the bone marrow and withdrawing cells. The bone marrow was then prepared using a separator device that spins the cells down and separates out the needed cells. These cells were then mixed with a special powder to make a paste that could be placed into or onto the lesion.
Results were measured by comparing MRI images before and for up to four years after the procedure. MRIs are able to show the location and depth of the defect as well as the presence and percentage of regenerated tissue and condition of the cartilage and bone. MRIs also show how well the new cells are integrated into the surrounding cartilage, joint surface, and edge of the lesion.
Clinical outcomes were measured using pain, motion, weight-bearing status, ankle alignment, physical activity, and level of sports participation. At first, scores for the tests used to measure clinical outcomes showed a significant improvement. But between two and three years after the procedure, there was a decline in scores. Three-fourths of the athletes were able to go back to their previous level of sports participation. The remainder either shifted to a different activity or sport (with lower impact) or resumed their previous sport at a lower level than before the injury.
By analyzing all the data, the researchers were able to show that the larger the lesion and the longer the time between injury and repair, the worse the results. This conclusion has also been reported in other studies (using other repair techniques).
The authors suggest that this one-step arthroscopic approach using stem cells as a reparative agent has some potential. It is less expensive than other treatment techniques and does not require multiple surgeries. There were no complications in this group of patients. Many patients were able to return to normal but a few were actually worse off afterwards compared with before the procedure. It was thought that the lesions in these cases were deeper than in other patients who had a good result.
Patients who develop more tissue like hyaline cartilage and less like fibrocartilage have a better chance of good recovery. Specifically, patients who had 80 per cent hyaline cartilage with only 20 per cent fibrocartilage had the best results. More study is needed using this one-step stem-cell procedure and comparing results with other techniques before it will be used over other methods of repair.