Articular Cartilage Damage Treatment
Articular cartilage is a unique tissue in joint that is constantly subjected to stress and is very vulnerable to traumatic injury or degenerative conditions. This is especially true in large weight-bearing joints such as the knee. When a teenage, young adult, or middle-age adult has a localized area of a full thickness cartilage or a full thickness cartilage and bone defect, this is in effect a localized area of osteoarthritis.
In patients with large defects, or in defects involving the bone, an effective treatment for the cartilage deficiency is a fresh osteoarticular allograft. These allografts are obtained from young donors who had the same size knee as the affected patient.
The workup for determining if a patient is a candidate for a fresh osteoarticular allograft is very important. Alignment must be assessed to make sure they are not putting extra stress on the affected compartment, the patient should have intact ligaments so there is no instability (or be able to have a concurrent ligament reconstruction), and it is important to determine that the patient has a normal amount of meniscus present to provide cushioning to the joint so that the joint is not overloaded. In addition, it is important that there not be cartilage lesions on the opposing articular cartilage surface, “a bipolar lesion”, because these types of lesions do not do as well with any type of cartilage resurfacing procedure. Another important piece of the workup is obtaining sizing x-rays of the knee such that the appropriate size donor graft can be obtaining in the future.
Description of Osteoarticular Allografts
The fresh osteoarticular allograft needs to be implanted via an open incision that allows access to the joint. In most locations of the knee, these incisions can be small, which helps to avoid any quadriceps muscle shutdown. However, there are times when they are in difficult to access locations where the incisions must be larger to make sure the graft can be properly placed.
One of the keys for success of osteoarticular allografts is transplanting a refrigerated allograft within the first 15-28 days postoperatively. It takes 14 days for assessment of the grafts to make sure there are no viral or bacterial contaminants. We strive to implant the grafts as soon as possible once they have passed testing to try and provide the most viable cells to the patient.
Fresh osteoarticular allografts have been found to result in significant functional and clinical improvement after an average follow up of three years, in our patient who have been treated for a full thickness osteochondral defect to the femoral condyle, with similar outcomes to historical reports in other centers for patients treated with fresh osteoarticular allograft implants.
It is very important that a careful assessment be made as to whether a patient is a candidate for this surgery. In addition, while this procedure is not felt to be a cure for arthritis, many patients can get 10 years or more of significant improved outcomes with this surgery. In effect, this is a “biologic resurfacing” procedure and it is important to recognize that not all patients can return back to full impact activities after the surgery.
Are you a candidate for an osteoarticular allograft procedure?
There are two ways to initiate a consultation with Dr. LaPrade:
You can provide current X-rays and/or MRIs for a clinical case review with Dr. LaPrade.
You can schedule an office consultation with Dr. LaPrade.
(Please keep reading below for more information on this treatment.)
Post-Operative Protocol for Osteoarticular Allografts
Patients who receive a fresh osteoarticular allograft need to be non-weightbearing for 8 weeks after surgery. During this time, they are in a continuous passive motion (CPM) device for 8-10 hours per day. In patients with a single donor plug, they are allowed to work on a stationary bike once the surgical incision is adequately healed (usually at about two weeks after surgery). Physical therapy is initiated immediately after surgery to work on quadriceps muscle reactivation, knee motion, and to control swelling.
At 8 weeks postop, radiographs are obtained to verify sufficient healing of the donor graft. Once adequate healing is confirmed, patients are progressed on a partial weight bearing program, advancing at ¼ body weight per week until they are fully weight bearing. The use of a stationary bike with resistance and leg presses at ¼ body wright are also initiated.
Patients may fully wean off crutches at 3 months postop and progress in proprioceptive and agility exercises. Impact activities need to be approved by the surgeon and may be initiated at between 6-9 months after surgery.
RELATED STUDIES
Osteoarticular Allograft FAQ
1. What is an osteoarticular allograft?
An osteoarticular allograft is a piece of bone and cartilage that has been obtained from a young donor and is implanted into a full-thickness cartilage defect in one’s knee. Osteoarticular allografts need to be sized correctly, tested to ensure there are no bacteria and viruses, which usually takes a minimum of 14 days, and implanted into a defect with a maximum depth of the bone being implanted of 1 cm. In addition, because the bone can be rejected by the recipient person, the blood products should be thoroughly washed out of the donor bone to minimize the chance of a rejection episode or formation of cysts. The donor bone heals by creeping substitution and this can take anywhere from 1 to 2 years to be thoroughly incorporated. With a proper rehabilitation program and a well-chosen patient, osteoarticular allografts are felt to be the gold standard for the treatment of cartilage defects of the knee.
2. What are the criteria that must be followed for one to have a successful osteoarticular allograft surgery?
There are several factors that should be worked up for every patient to ensure the maximum success rate after an osteoarticular allograft transplant. First, the patient should have normal or correctable alignment. This is because if they are malaligned with the weightbearing going into the compartment for the planned osteoarticular allograft, the success rate in the peer-reviewed literature has been shown to be much less. In addition, one should have a good “cushion” of meniscus in that same compartment. The meniscus is important as a shock absorber, and if one does not have a meniscus or has a significant loss of meniscus, the cartilage in that compartment and the donor graft will wear out much faster. Another factor to look at is whether knee stability is present. If one has an unstable knee, the outcomes of a fresh osteoarticular allograft are also less successful. Therefore, if one has ligament instability, the ligament instability should be corrected, most commonly at the time of the fresh osteoarticular allograft procedure, to maximize the patient’s outcome. Finally, the cartilage on the opposing surface of the donor fresh osteoarticular allograft should also be normal or nearly normal. If one has significant wear of the opposing surface, the osteoarticular allograft procedure has a much lower chance of working. Thus, the basic workup for determining if one is a good candidate for a fresh osteoarticular allograft includes the alignment, assessment of ligament stability, assessment of the amount of meniscus in the same compartment, and also the opposing cartilage surface condition.
3. What are distal femoral osteoarticular allografts?
Distal femoral osteoarticular allografts involve a graft that is obtained from either the medial femoral condyle or the lateral femoral condyle on the end of the thigh bone. The most common distal femoral osteoarticular allograft involves the medial femoral condyle, whereas the lateral femoral condyle osteoarticular allografts tend to be larger. Osteoarticular allografts of the distal femur, in well-chosen patients, are among the most successful cartilage resurfacing procedures available.
