Articular cartilage damage is one of the most challenging injuries orthopaedic surgeons face. Traditionally we have had few options to rebuild or replace the cartilage lining the ends of the bones. Once bone-on-bone arthritis develops, joint replacement is a common salvage operation. Before that point, microfracture, autologous chondrocyte implantation, and OATS procedures have been attempted to restore a healthy joint.
Allograft osteoarticular transplants (allograft OATS) have been utilized for years to replace very large cartilage and bone defects. Transferring one or several smaller cylinders of bone and cartilage can fill smaller defects. Using a larger cylinder of bone and cartilage from a donor – an osteochondral allograft transplant – can fill defects as large as 30 mm in diameter.
A study presented recently at the American Orthopaedic Society for Sports Medicine’s Specialty Day in Chicago suggests that osteochondral allograft transplant surgeries might be unlikely to allow patients to return to full activities.
James S. Shaha, MD et al collected data on 38 military patients who underwent these surgeries performed by four experienced surgeons. They obtained follow-up results at an average of 4.1 years. They measured return to duty in terms of a patient’s ability to perform tasks pertaining to his or her military occupational specialty. Full activity required being able to complete physical fitness tests, participate in routine physical training, deploy to a combat theatre, and participate in recreational sports.
Their findings are somewhat discouraging. 28.9% of the patients returned to active duty. Only 5.3% returned to pre-injury level of duty. “Cartilage injuries in the high-demand, athletic population remain a clinical challenge. Our study contrasts recent literature which suggests a high rate of return after the OATS procedure and further demonstrates that physicians must carefully interpret what “return to activity” means to different populations,” observed Shaha.
Unfortunately these results don’t reflect a problem with the surgical treatment as much as the injury itself. Since we have never had great success making normal hyaline cartilage grow in an area of damage, we often try to transplant healthy bone and cartilage from other areas of the joint or from donors.
While these procedures might fill holes in the knees and provide smoother, more durable surfaces than existed before, they may not withstand the rigorous demands of aggressive physical activity, such as military duty. While these results were those specifically of patients in military service, it seems reasonable that they would correlate with people who play sports or perform demanding physical exercise on a regular basis.
Much more research is needed to try to improve results of surgical procedures and nonoperative treatments for articular cartilage damage. Possible modifications of these surgeries or other treatment ideas might one day allow active patients to return to demanding activities and healthy lives.
Note: The following post appears in a modified form as an article I wrote for Becker’s Orthopedic Review.