COLLAGEN MENISCAL IMPLANTATION (CMI)
The meniscus is a pliable substance that sits between two bones in the knee joint, the femur (thigh bone) and tibia (shin bone). Some patients with meniscus tears can be treated with a combination of activity modification and a focused physical therapy program. Other patients with persistent symptoms or certain tear patterns require surgery. In patients with certain tear patterns, Dr. Keller may recommend surgical reconstruction of part of the meniscus.
Dr. Keller always tries to retain as much healthy meniscus as possible during surgery because patients are more likely to develop arthritis without a meniscus. Large meniscus tears in the central region do not heal and these tears are often excised (partial meniscectomy). If a large portion of the meniscus is torn and/or removed, Dr. Keller may recommend a surgical reconstruction of part of the meniscus. This procedure is called “Collagen Meniscal Implantation.” Collagen is a natural scaffold found in the human body that helps promote cell growth and new tissue formation.
During surgery, Dr. Keller measures the length and width of the damaged part of the meniscus. Next, he sizes the collagen graft to match the area of damaged meniscus in the patient’s knee. Dr. Keller then uses a special device to pass stiches, and he sews the collagen graft to the patient’s healthy remaining meniscus. Over time, the collagen graft matures into a fibrous-meniscal substance that helps protect the cartilage in the knee. There are several peer-reviewed articles that suggest that this procedure helps protect the knee joint and may help prevent the onset of arthritis in the knee.
Following surgery, patients are placed in a hinged brace that is locked straight. Dr. Keller recommends partial weight bearing for 4-6 weeks in the brace. When the patient is sitting or lying down, Dr. Keller encourages knee range of motion exercises with the brace removed. Dr. Keller also recommends intermittent icing and straight leg raise exercises to strengthen the quadriceps muscle. Dr. Keller recommends starting physical therapy two weeks after surgery. Physical therapy focuses on reducing swelling in the knee, restoring full range of motion, and eventually, restoring strength to the knee. Most patients can start full weight bearing on the affected leg 4-6 weeks after surgery. Most patients start cutting activities and sporting activity approximately 4-6 months after surgery.