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Home , Lateral meniscus, Medial meniscus, Meniscus (anatomy), Meniscus tear

Treating Tears Recognizing and caring for a common problem By Michael R. Meisterling, MD

eniscus tear is a common knee In particular, patients with anterior cruciate either in a squatting activity or by direct that orthopaedic surgeons (ACL) disruptions depend signifi- contact such as might occur in a sporting often see. Patients typically start cantly on their for knee activity. Many also occur by a twist- Mto develop meniscal tears in their adolescent stability. ing or torsional component that occurs when years and continue to develop them through- the patient is in a squatting position. As out life. Younger patients tend to have more Why is the meniscus important? The people age, many injuries seem to be part of traumatic problems that lead to the injuries meniscus is important because it dissipates the aging process. For example, as patients and exhibit easily identified points of injury. force across the knee . In a normal pa- exceed 50 years of age, many who exhibit a As people age, they tend to have more tient, the force across the knee joint during tear in their meniscus on an MRI will have insidious onset of pain and less distinct walking can be two to four times that of the experienced no pain. Other patients develop injuries that cause their meniscus tears. normal body weight. When running or going tears in their meniscus because of laxity in Ultimately, meniscus tears seem to be a down stairs, the force across the knee joint their knee either as a normal part of their part of the aging process with respect to the can be six to eight times the patient’s body physiology or because they have previously tissues of the knee. weight. In walking and running activities, the had a ligamentous injury that has allowed the meniscus dissipates all this force and relieves knee to function with more laxity than it was What is a meniscus? Meniscus is a durable, the joint’s reactive forces, thus preventing intended to have. rigid, fibrous tissue present on both sides development of progressive degenerative or of the knee — the medial or inside as well arthritic changes. What are the symptoms of a meniscus as lateral or outside of the knee. Frequently tear? Most patients develop pain in their when people mention the meniscus of the How does the meniscus get injured? In knee joint and frequently point to the medial knee they refer to it as , a specific younger patients, the meniscus frequently or lateral side of the knee. It is particularly type of cartilage that acts as a weight-bearing gets injured by a direct compressive force unusual for a to cause pain structure in the knee.

Where is the meniscus? The meniscus is located in the knee between the or shin and the or bone. There is no meniscus in the knee between the or kneecap and the femur. The meniscus be- tween the tibia and femur on both the inner and outer portion of the knee is a crescent of tissue. The medial meniscus tends to be semilunar in shape, and the is almost circular.

What does the meniscus do? The menis- cus accepts structural weight-bearing in the knee and helps protect the knee from or wear-and-tear type arthri- tis. The medial meniscus accepts about half the weight-bearing force on the inner side of the joint. The lateral meniscus accepts about two-thirds of the weight-bearing force on the outer side of the joint. With squatting activities, the force transmitted through the meniscus is even greater than in the standing position. The meniscus, both medially and laterally, also acts to help stabilize the knee Meniscus tears can result from squatting or from direct impact or torsional compressive forces on the knee in patients who have a ligamentous injury. such as occur during competitive . Incidence of tears increases as individuals age beyond 50.

4 ORTHOPAEDIC EXCELLENCE that seems to localize to the kneecap or pa- symptoms over a six- to 12-week period. removal of the torn cartilage. Rather, the tella. Many patients, depending on the size of There is also a group of patients with small forces increase because of the damage done the tear, can develop locking if there is a large tears that can heal on their own. at the time of the tear. If the entire meniscus tear or if jamming and catching sensations is removed, the forces on the knee joint on occur with smaller tears. Other patients de- What will an injection do for my torn the medial side can increase twofold. On velop swelling at the time of the injury or on meniscus? When patients have an injection the lateral side they can increase up to three a recurrent basis as the torn meniscus slides for a torn meniscus, typically the injection and a half times the normal force. For some into and out of the joint and into a symptom- atic position. Almost all patients find it very difficult or at least aggravating to do - ting activities.

How is a meniscus tear diagnosed? Most patients with a meniscus tear can be diag- Femur nosed by the history of how their knee be- came symptomatic, combined with physical examination by an experienced physician. Most typically, the exam will reveal that the Meniscus patients have tenderness over the medial or lateral side of the joint, particularly exacer- bated by deep flexion of the knee with rota- tion of the tibia on the femur. MRI is often very helpful in identifying the presence of a tear. The gold standard for confirming and diagnosing meniscus tear is , where a small camera is placed into the knee. This allows treatment of the injury at the time of diagnosis.

What are the treatment options? Treat- ment options for meniscus tear are based on significance of symptoms and the patient’s age. Many patients can start with observa- Meniscus is the rigid, fibrous tissue in the knee joint separating weight-bearing surfaces of the femur, or thighbone (top), and the tibia, or shinbone. The meniscus cushions the two and helps prevent tion and do not necessarily need surgery. osteoarthritis. Tears in the durable meniscus cartilage cause pain and can limit movement. Particularly in elderly patients, the use of anti-inflammatories such as ibuprofen and Aleve combined with Tylenol often can al- is a type of cortisone or steroid that blocks patients with significant in the joint, leviate the symptoms. Other patients benefit inflammation within the joint. The injection removal of the torn meniscus can actually from an injection such as cortisone or ste- combines a local anesthetic or Novocain- increase pain. For patients with underlying roid. However, another group of patients who type medication with the steroid, which ligamentous tears, the may become continue to have ongoing symptoms war- allows the joint to be numbed at the time more unstable with removal of all or part of rant surgical intervention. For patients who of injection to block the pain cycle imme- the meniscus. However, among appropriately proceed in a surgical direction, most have diately. Over a period of weeks, the steroid selected patients, most ultimately get signifi- the torn piece of knee meniscus removed at component of the injection tends to help cant improvement in their quality of life by the time of arthroscopic surgery. However, alleviate swelling and inflammation. If the proceeding with arthroscopic debridement a small group of patients are candidates to symptoms of the meniscus tear are from of a torn meniscus. have the torn meniscus repaired. the acute inflammation and reaction to the tear, frequently patients can get long-term or What if a meniscus is repaired? For a Why would patients proceed with ob- permanent results from treating that inflam- young patient with otherwise good joint servation of a meniscus tear? Meniscus matory cycle. surfaces, repair of torn meniscus allows for tears can occur in patients who have very low restoration of the normal within the demand or have significant medical comor- What if the meniscus is removed? After knee. Once the meniscus repair has healed, bidities that make the risk of surgery unwar- surgical removal of the irritated and torn the ultimate expectation is that the patient ranted. There is also a group of symptomless portion of the meniscus, many patients get will return to normal function without con- patients with meniscus tears found inci- very rapid pain relief. At the time of sur- cern about the forces transmitted across the dentally with MRI when evaluating another gery, the portion of the meniscus removed joint. However, there is an increased rate of underlying condition. Many patients will get is no longer functional, so the increase in re-tear for patients who have had a meniscal improvement of their torn meniscus forces across the joint does not change upon repair. This risk seems to be present for >>

ORTHOPAEDIC EXCELLENCE 5 Treating Meniscus Tears two to five years at a re-tear rate typically seem to do very well with meniscus repair, decades to develop. The two most problem- around 15 percent. When a patient under- assuming that the tear is in the area of the atic complications seen with any frequency goes repair of a torn meniscus, the rehab meniscus that has a good blood supply. are deep vein thrombus (DVT) and pulmo- time is substantial because activities have nary embolism and infection. Patients are to be limited significantly for about three Which tears can avoid surgery and be ob- rapidly mobilized after surgery and allowed months while the tissue heals. Ideally, a served? Patients with small tears of less than to progress in activity as soon as possible, patient who has undergone meniscal repair 1 cm are good candidates to be observed, as which is the best treatment and prophylaxis would do limited activities beyond 90 de- many of these can be asymptomatic or heal for DVT and pulmonary embolus. To pre- grees of knee flexion after the repair. spontaneously. Also, tears with minimal vent infection, patients frequently receive antibiotics before surgery. As a result of mobilization and antibiotics, the risk for “The meniscus is important because it dissipates force DVT and infection remains quite low for across the knee joint. In a normal patient, the force across arthroscopic meniscal surgery. Another the knee joint during walking can be two to four times group of complications typically arises from underlying cardiovascular or pulmonary that of the normal body weight.” problems. Lastly, although infrequent, are – Michael R. Meisterling, MD complications due to the anesthetic used for the surgery. Who can have a meniscus repair? Patients displacement of less than 3 to 5 mm when who are typical candidates for meniscal visualized on the MRI have a high likelihood What happens after meniscal removal? repair are younger — ideally less than 20 of being minimally or completely asymptom- Patients typically go home within a few years old. Younger patients tend to do better atic for many patients. Patients with degener- hours after the surgery. They are allowed to because they have a better blood supply to ative tears who also have significant arthritis progress in weight bearing and usually do the meniscus, which is necessary for repair. in the joint most often should be observed, not require crutches for activities. Patients In addition to concerns for age, the size of as the arthritis seems to produce symptoms typically receive a set of to start the tear is also significant. Patients who have in many of those patients. Patients who only working through the day after surgery and a 1- to 3-cm tear tend to be the best candi- have a partial tear that does not extend to the can proceed with a desk job several days after dates for meniscus repair. Different kinds of surface also tend to do very well with obser- surgery. They can progress to light labor and tears can occur, and only a small percentage vation and avoidance of surgery. within one to two weeks. of them occur in areas with Typically patients can do unrestricted activ- blood supply within the me- How are meniscus tears treated with ity by eight weeks after surgery. Occasionally niscus. Patients who have surgery? The standard of treatment at this we use bracing to help patients in their post- a tear outside the blood time for a torn meniscus is arthroscopic sur- operative period. supply experience no gery. This involves the use of a small camera benefit from menis- passed into the joint to allow direct visual- What happens after repair? Similar to cus repair. Patients ization of the entire working apparatus of removal of a meniscus, patients usually go who have recon- the knee. This surgery typically is done using home several hours after surgery. Patients struction of an two or three small incisions to allow passage are typically on crutches with protected ACL tear also of the camera and working instruments into weight bearing for six weeks after their me- the knee. Through these small incisions we niscus repair. Physical therapy usually begins can pass in tools to remove the torn parts of within three to seven days. Weight bearing the meniscus with minimal morbidity to the progresses over the period of six to 12 weeks patient. For patients with previous repair of postoperatively. Braces may used during this the meniscus, depending on the method of period. Finally, patients are typically allowed repair, an additional small incision may also to return to full activity three to six months be required. after surgery. OE

What are the most common risks of Michael R. Meisterling, MD, com- surgery for a torn meniscus? The most pleted his residency at the University common problem with surgery for a torn of Minnesota Department of meniscus is that the patient’s symptoms Orthopaedic Surgery, followed by a return. The return can result from a re-tear Sports Medicine Fellowship at the or because arthritic symptoms develop. Adidas Sports Medicine Clinic. Dr. Meisterling is Board Certified in orthopaedic surgery and is a Almost all patients with meniscus tears find The return of these symptoms may occur candidate member of the American Academy of squatting very difficult or at least aggravating. over several months or may take several Orthopaedic Surgeons.

6 ORTHOPAEDIC EXCELLENCE