Meniscal transplantation (replacement or reconstruction) is gaining popularity in the treatment of patients under age 50 with early evidence of post-traumatic arthritis. At Cleveland Clinic, we reserve meniscal transplantation for minimally to moderately symptomatic patients with large, irreparable tears.
Meniscal injuries of the knee can occur at any age, but are most common in people age 30 to 50. Younger people tend to injure (tear) their meniscus in athletic endeavors, while older people sustain tears from minimal insults, such as twisting while getting out of a chair or golf cart.
The main function of the C-shaped cartilage is load transmission. The meniscus distributes forces between the femur and tibia over a larger surface area to reduce the point-contact forces of articular cartilage. They aid in joint lubrication and nutrition, and the medial (inner) meniscus acts as a “backup” stabilizer to the knee following anterior cruciate ligament (ACL) injury.
Because the majority of the meniscus has no blood supply, it is unable to undergo the normal healing process that occurs in most of the rest of the body when it sustains an injury.
Treatment for symptomatic meniscal tears may include meniscus repair, partial meniscectomy and meniscal transplantation. Meniscus repair is advocated whenever possible, especially in young patients, because it can restore normal function in the knee.
However, the most common treatment for meniscal tear injuries is arthroscopic partial meniscectomy, which is also the most common orthopaedic surgical procedure. Partial meniscectomy decreases symptoms (locking, clicking, pain, swelling, etc.) associated with a meniscal tear, but is reserved for irreparable tears because it does not alter the natural history of the disease, which often leads to osteoarthritis.
The medial (inner) meniscus is more frequently transplanted than the lateral (outer) meniscus because medial meniscal injuries are more common. Appropriate candidates for transplantation include patients with stable, well-aligned knees and minimal to moderate symptomatic, post-traumatic arthritis.
The physician should correct any malalignment and/or “looseness” of the knee prior to meniscal transplantation for the best results.
In meniscal transplantation, the remaining meniscal tissue is first removed. A fresh-frozen cadaver meniscus, preoperatively sized to the patient’s knee, is then implanted in the knee under arthroscopic guidance. Either a bone trough (lateral) or bone tunnels (medial) are used to anchor the boney attachments, and sutures are then placed to the native meniscal rim or capsule.
The outpatient surgery involves a 23-hour stay. Patient must use crutches for four to six weeks, and undergo rehabilitation to regain motion and strength. They can return to heavy labor in three to four months, and to sports in six to nine months.
Clinical studies have demonstrated a 75 to 85 percent success rate for meniscal transplantation, defined as reduction in pain/swelling, increase in activity and delay in the inevitable progression of post-traumatic arthritis. However, until long-term studies can determine the exact reduction in the rate of progression, this procedure is not recommended for asymptomatic patients.