Meniscal Tears
The menisci (the medial meniscus and the lateral meniscus) play a number of important roles in proper knee functioning. They act as shock absorbers between the bearing surfaces in the knee, they evenly distribute the compressive forces from the femur onto the tibial plateau, and they provide both lubrication and stability for the knee joint. While meniscus injuries may be acute or degenerative in nature, they often require prompt surgical intervention to avoid later damage to the cartilage in the knee joint.
The Role of the Meniscus
Located in the space between the distal femur and the tibial plateau, the elastic crescent-shaped menisci (the medial meniscus and the lateral meniscus) play a number of important roles in proper knee functioning. Their remarkable physical properties enable them to function as shock absorbers between the bearing surfaces of the knee and distribute compressive forces from the femur more evenly across the tibial plateau. Indeed, without the menisci, the knee joint would be exposed to loads of up to six times greater than its normal. The menisci also help to lubricate the sensitive surface cartilage between the tibia and femur. Moreover, given the firm attachment of their thicker outer portions to the joint capsule, they make an important contribution to overall joint stability.
The most common meniscus injuries are tears, including incomplete and complete tears. The cause of these tears is either acute (i.e. resulting from injuries) or degenerative (i.e. relating to the general aging process).
Given that meniscus injuries can impede joint function and lead to potentially irreversible joint damage (e.g. osteoarthritis) it is essential to consult with your doctor as quickly as possible in cases of suspected injury. Only an experienced orthopedic specialist can determine wither a meniscal tear will heal on its own or will require surgery.
What are the symptoms of a torn meniscus?
The good thing about the pain associated with a torn meniscus is that it will reliably let you know that something is wrong with your knee. You may experience a jolt of pain when rotating your knee or when standing up from a squatting position. Sudden stabbing pain of this sort occurs most often in the case of an accident or sports-related injury to the meniscus. Sudden losses in the knee's range of motion or weight-bearing function may also point to an acute meniscus injury.
A painful inability to extend the leg or a snapping sound is often an indication of a particular tear known as a bucket-handle tear.
Degenerative processes, which are characterized by diffuse, sporadic or gradually increasing levels of pain and discomfort in the knee, are much more troublesome than acute injuries. These may also be accompanied by effusion and heat as well as knee pain that increases throughout the day. Even minor events (false moves) can trigger a rupture in meniscal tissue that exhibits significant degeneration.
When is surgery necessary?
Surgery is not always necessary for a torn meniscus. The chances of self-healing may be very good, depending on the type and location of the tear as well as the age of the patient and the general condition of the tissue. Sports-related meniscal tears in young patients who show good tissue quality stand a particularly good chance of healing completely. The chances of spontaneous healing are also good when the tear is in the outer third of meniscus because the supply of blood is better at near the outer edge of the meniscus. In all such cases, physical therapy offers a good method of accelerating the healing process.
In contrast, there is almost no chance of spontaneous healing in the case of degenerative tears. Depending on the degree of the pain involved and the degree to which the patient's range of motion is reduced, it may be advisable to introduce conservative forms of treatment as a means of delaying surgery for degenerative tears. This, however, will not eliminate the cause and could encourage an asymptomatic patient to wait too long (i.e. when secondary damage has already been occurred) to initiate further medical care. As a precaution, arthroscopic surgery might be performed in such cases to get a better look at the condition of the joint cartilage. Better patient outcomes often depend on early diagnosis and early treatment.
The aim of arthroscopic surgery is to conserve as much of the natural meniscal tissue as possible so as to ensure the long-term functional capacity of the joint.
However, some degenerative injuries may make it necessary to remove a part of the meniscus. Here, too, it is essential to remove as little functional meniscal tissue as possible so as to help ensure better long-term prospects.
What types of meniscus surgery are performed?
Meniscal Repair
A tear in an otherwise healthy meniscus - especially a tear near the outer edge of the meniscus where the blood supply is sufficient - can best be repaired using sutures. Special sutures and modern suturing techniques used during arthroscopic surgery permit excellent patient outcomes. Having assessed the size and the location of the tear, an experienced surgeon will make a decision as to which suturing technique is to be used.
Even in the case of relatively serious and large bucket-handle, it is important to conserve as much of the meniscus as possible so as to limit the risk of osteoarthritis.
Meniscal Transplantation
This procedure involves transplanting a meniscus from a donor to treat patients whose meniscus cannot be sutured on account of the size or location of the tear or because a significant portion of the meniscus has already been lost.
This procedure is also commonly used in very young patients so as to prevent cartilage damage and the early onset of osteoarthritis.
Both the medial and the lateral menisci can be replaced in this manner. It is especially important to determine the exact size and position of the meniscus that is to be replaced while conducting diagnostic examinations.
The necessary donor menisci are obtained from an international transplantation center. The main risk here is that the waiting period for a suitable donor meniscus will be too long. Fortunately, menisci do not trigger the rejection that is associated with the transplantation of other organs. Given that the meniscus is removed under sterile conditions and is investigated for the presence of pathogens, the risk of infection is exceptionally low.
The minimally invasive arthroscopic procedure used to insert and suture the prepared meniscus usually takes around two hours.
Meniscal Replacement
Synthetic meniscus tissue is used primarily to compensate for partial injuries and damage to the medial and lateral menisci. The porous nature of this newly developed, sponge-like material permits the in-growth of small blood vessels. This in-growth is then followed by the propagation of autologous tissue. The artificial meniscus is then dissolved and disposed of by the body as soon as the newly developed natural tissue takes up its function.
At our clinic, we carry out this procedure using minimally invasive arthroscopic surgery. This means that the smallest incisions are used and as much healthy tissue is conserved as possible.
We have achieved outstanding patient outcomes when using this procedure to treat painful meniscal defects. Sufficient data are not yet available for an evaluation of the procedure's long-term outcomes.
What happens after surgery?
After simple resectioning of a meniscus, patients will be allowed to move about on crutches on the same day they undergo surgery. These patients are usually able to return to work after 1 to 2 weeks, unless their work involves higher levels of stress for the knee. With a proper degree of caution, patients are then allowed to begin playing low-stress sports such as cycling after one week. Swimming may be considered only after the wound has healed completely. Sports that are typically more stressful for the knee (e.g. soccer, tennis and basketball) are usually permitted after 3 to 4 weeks.
Meniscal repair is generally followed by an approximately 4-week phase of protective weight bearing with the aid of crutches. The transition to full weight bearing begins in the fifth week. Patients will be expected to wait for a period of 6 to 8 weeks before beginning to play low-stress sports and 6 months before playing sports involving greater levels of stress for the knee.
The protective weight bearing phase for meniscal transplantation is around 5 to 6 weeks. Patients will be expected to wait for a period of 6 to 8 weeks before beginning to play low-stress sports. Your surgeon will provide you with all the information you need regarding periods of protective and full weight bearing.
A regimen of physical therapy to support the healing process should be followed in all cases. Once the healing process has begun, the pain and discomfort will also begin to disappear. This usually comes after a period of 6 to 8 weeks.
