Injuries, defects, lesions, or tears of any kind in the joint cartilage can end a sports athlete’s career. Today, there are improved ways to treat cartilage injuries, especially in the knee. One of those methods is called mosaicplasty. This article reviews the uses and long-term results of mosaicplasty in an athletic population.
What is mosaicplasty? It’s a form of osteochondral autografting. That doesn’t really explain anything, does it? Let’s start with the last part of the term: grafting tissue is the moving of some type of soft tissue from one spot to another. It could be ligament, tendon, muscle, or as in this case, cartilage. Autografting tells us the donor tissue being harvested to repair the problem is coming from the patient himself.
Osteochondral can be broken down into two words: osteo for bone and chondral meaning cartilage. So with osteochondral, we have cartilage that has pulled away from the joint with the underlying next layer of bone still attached. We call this kind of damage a full-thickness defect. That is the injury side of things.
Now the repair side of the problem: mosaicplasty. During this procedure, the surgeon harvests cartilage and bone from an area of the knee that doesn’t get much action and isn’t under the pressure of constant weight bearing. The donor or graft is smoothed and shaped to fill in the defect site. Sometimes only one donor plug is needed but some patients in this particular study had as many as nine grafted pieces.
What are the advantages of this treatment? And who is considered a good candidate for the procedure? Mosaicplasty can help save the joint and protect it from further wear and tear around the defect site. Normal joint biomechanics can be restored with this technique and get the athlete back into full sports participation sooner than later. With seasonal sports and a limited amount of playing time, faster return-to-sports can be a huge benefit of a successful mosaicplasty.
Among the athletes with cartilage damage, who can benefit? The results of this study confirm what other studies have shown. Younger athletes who have smaller (and fewer) lesions seem to do the best. But location of the lesion was a key risk factor for successful outcomes. Lesions located on the femoral condyles (large round knobs at the end of the femur (thighbone) seem to respond better than damage or defects to the patella (kneecap).
Athletes from all types of sports were included with no real difference in results based on their sports injuries. Soccer players, handball, water polo, wrestling, gymnasts, and many others had equally good results. Only a small number of patients suffered from post-operative complications such as hemorrhage, infection, or persistent pain and swelling. At least in this study, sex (male versus female) was not a significant factor.
The researchers found that there were some other specific factors that influenced success or failure. For example, smaller defects tended to have less degenerative wear and tear but the plug to fill those holes wasn’t so tough. It’s more difficult to harvest a small amount of cartilage and the smaller grafts are more fragile. The larger graft plugs are more stable making them easier to harvest and insert.
Age was another risk factor for success/failure. Athletes younger than 30 years old had better success rates. Good alignment of the joint is also important. Biomechanics of joint movement that are off or uneven in any way (and not repaired before mosaicplasty) can contribute to uneven forces or load on the joint. Joint degeneration is the result of overuse and uneven weight bearing.
The authors summarize the results of their study by saying that the data supports the use of mosaicplasty for small-to-medium sized osteochondral lesions. Even in high-demand athletes, the grafts seem to hold up well over time with very few postoperative problems. Those problems that did occur (e.g., pain with weight-bearing) were temporary and went away within the first six weeks up to one year.
Problems with donor site pain, swelling, and bleeding may be ended in the near future. Researchers are exploring the use of biodegradable donor site plugs that would fill the harvested empty sites until they fill in on their own with scar tissue. Putting an end to donor site pain is important in an athletic group of patients who are very active participating in vigorous exercise.