Meniscal allograft transplantation (MAT) is a fairly new way to repair (rather than remove) damaged meniscus in the knee. It is an example of how the treatment of meniscus injuries has progressed and changed over the years. Meniscectomy (removing the meniscus) was the first procedure used. But long-term studies showed degeneration of the joint cartilage occurred as a result.
Researchers have been able to discover a way to transplant meniscal cells to help repair damaged areas of the meniscus. The transplanted cells can come from a healthy part of the patient’s own meniscus. This would be called an autologous transplant. Cells harvested from a donor can also be used. This type of transplant is called an allograft.
Rehab would be the same following either type of meniscal transplantation (autologous or allograft). According to a recent study from the Navy Medical Center in Bethesda, Maryland, a six-week rehab protocol begins with nonweight-bearing exercises using a continuous passive motion(CPM) machine.
The leg is placed in the CPM. The device slowly and steadily bends and straightens the knee joint. The amount of movement is regulated and progressed by five- to 10-degrees at a time. The unit is used for two hours at a time, and then the patient is given a rest. The patient spends a total of six to eight hours a day using the CPM. When out of the CPM device, the patients wear a hinged-knee brace with the knee held in a straight position.
The CPM unit is discontinued when the patient has 90-degrees of knee flexion. The brace is unlocked to allow some motion at the end of four weeks. Increasing amounts of active knee flexion are allowed as muscle control is improved. A physical therapist will guide you through this process. Patients are expected to regain full motion in eight to 12-weeks. With consistent attention to a home program, strength, motion, and function are fully restored by nine to 12-months.