Osteoarthritis of the knee is a very common condition that affects millions of people every year. Arthritis of the knee is whenever the cartilage of the knee is lost. There are two types of cartilage. First is the meniscus. The meniscus is a rubbery cushion that comes between the two bones of the knee. It provides the initial zone of protection. Very commonly, a meniscus can be torn with day-to-day activities wear and tear, or even a high level of sports. The treatment of a meniscus tear, if it is symptomatic enough and fails to respond to therapy and/or injections, is an arthroscopic procedure. During the arthroscopy, the meniscus is either sewn back together or trimmed out, depending on the location of the tear. The second type of cartilage is articular cartilage. It is a cap that covers the top of the thigh as well as the top of the shin bone and is like gristle. Whenever damage to the articular cartilage occurs, this sets the stage for arthritis. The process goes from the cartilage cap becoming soft to small crevices, to big flaps to bare bone. Once the knee gets to bare bone, the patient experiences constant pain that can limit their activities. Typically, these patients have pain with rest as well as pain with walking short distances that is quite disabling and the end result historically has been a total knee replacement.
At Advanced Orthopedic Specialists, we established the Cartilage Restoration Center for the patients under the age of 55 who have arthritis that has progressed to the point of possibly needing a knee replacement. There are two types of cartilage restoration procedures that we perform at AOS to try to halt this progression. First is the meniscus preservation technique. If a patient has a meniscus tear which is repairable, we, through the arthroscope, can sew it back together and anticipate a good result. If; however, the patient has lost the majority of the meniscus during a prior procedure or during an injury, they could be a candidate for a meniscal allograft. The meniscal allograft is when a cadaver cartilage is taken and inserted into the knee with the assistance of an arthroscope and allowed to heal back in. We have had good success with this performing hundreds of these at Advanced Orthopedic Specialists. This is the first step to stop the progression of the arthritis.
The second type of cartilage restoration procedure involves the articular cartilage, which is the cartilage cap. There are a variety of options to restore the cartilage cap depending on the number of defects, the size of the defects, and the location of the defects. If there is a small isolated defect, the patient may be a candidate for an osteoarticular autograft (OATS). In this technique, a graft is taken from part of the knee, which is nonweightbearing and transferred to the defect in the knee. This is similar to backfilling the hole on putting green. This offers excellent results for lesions that are less than 2 sq cm.
If the lesion is larger than 2 sq cm, the options are an osteoarticular allograft, which is a large plug of cadaver cartilage, which is transferred to the defect.
Another option is autologous chondrocyte implantation. At advanced Orthopedic Specialist, we have performed over 300 ACIs. In this technique, a knee is scoped and multiple small specimens are taken from a non-weightbearing part of the knee. They are sent to a company in Boston where they are multiplied to approximately 48 million of the patient’s own articular cells and these cells are then inserted into the knee where they are allowed to grow. This is a stem cell technique. This has had 85% success rate.
Using the combination of meniscal allografts as well as osteoarticular autografts, ACI, and steoarticular allografts, we have been able to salvage the knee in over 500 patients in the past eight years and prevent the patients under the age of 55 into having a total knee arthroplasty. We feel this is the future of knee surgery. We expect that this will ultimately replace the need for knee replacements in our patient population and the age limit of 55 will be extended.
If you have any questions about this procedure, please contact us.
Written by, Dr. Christopher Arnold