Meniscal transplants are indicated when there is adequate loss of meniscal tissue either from an injury or previous surgeries as well as continued joint line pain. The meniscal transplant is from a cadaveric donor which has been matched to the specifications of the patient’s knee which can be determined from an MRI. To benefit from a meniscal transplant the patient needs to have good articular cartilage along the knee surfaces. Patients with moderate to severe arthritis are not good candidates for a meniscal transplant.
Hyaline cartilage covers the end of the bones and allows for joints to move freely with low friction. When people have injuries to the chondral surfaces of the bone, this cartilage is damaged. With small bone edema or defects they can heal on their own if treated properly, but many times they overlooked and lead to larger defects. When a larger defect occurs from either a deficient meniscus or an injury it sometimes requires the damaged area to be removed to stop further damage in the knee from occurring.
Osteochondral grafts are indicated for those patients who have:
- A full thickness cartilage loss/defect
- Symptoms of tenderness in a focal area, weight-bearing pain, effusion and have tried injections with little change in symptoms.
Autograft Osteoarticular Transfer Surgery (OATS)
An autograft osteochondral transplant surgery is often selected for those patients that have a smaller defect in the cartilage that needs to be fixed. It is beneficial to use your own tissue due to a lower cost, and good accessibility to graft. It is limiting due to the size that is able to be grafted from your knee. For this procedure, the physician will take bone from the lateral trochlea of the knee in the appropriate size needed to replace the area of the defect. This graft is usually taken from a non-weightbearing surface as to not cause more issues with healing or causing larger defects in the future. Graft sizes can range from 4mm to 10mm.
An allograft is most commonly used for medium to large defects that need to fixed. These are different from an autograft because they are used from a donor. The plugs are not matched by antigens or blood type but by size needed. The grafts can be fresh or frozen depending on what is needed and physician choice. They are often used in conjunction with a meniscal transplant in order to restore the cartilage of the knee.
Noyes, Frank R., and Sue D. Barber-Westin. “Noyes' Knee Disorders Surgery, Rehabilitation, Clinical Outcomes.” Noyes' Knee Disorders Surgery, Rehabilitation, Clinical Outcomes, Elsevier, 2017.