Treatment of a Torn Meniscus

The meniscus is a C-shaped, wedge-like, “rubbery” piece of cartilage in the knee situated between the femur (thigh bone) and the tibia (shin bone). It plays an important role in the functioning of the knee by enhancing stability and spreading out the stresses of the tibia – femur articulation.  Because of the stress on the meniscus in every day life and, in particular, in sports, the meniscus is the most commonly injured (“torn cartilage”) parts of the knee. The meniscus has blood supply around the rim only. If the tear is in the area of the blood supply, there is a chance that it might heal with help.

Signs and Symptoms

When the meniscus tears, the symptoms will vary greatly depending on the location, size, and type of meniscal tear. Some of the common signs and symptoms include:

Diagnosis

The history (H) and physical examination (PE) are important. Your medical team is going to ask question to try to determine what you were doing and what you felt at the time of the injury. It is important to know what you were able to do after the injury and whether or not there was any swelling or fluid in your knee. The PE is performed to try to determine the location and the size of the tear and to see if there are any other injuries in the knee. In most orthopaedic surgeons’ hands, an H and PE can accurately diagnosis a meniscus tear 85% of the time.

X-rays may be done to rule out osteoarthritis and fractures which could possibly be your problem or adding to the pain. Sometimes an MRI is helpful when you have too much pain to do a good exam, to help confirm the diagnosis, and/or to make sure there is no other injured structure in the knee in addition to the torn meniscus. An MRI can accurately make the diagnosis of the meniscus about 95% of the time.

Treatment

The meniscus gets its blood supply from its attachment to the lining tissue of the knee.  These blood vessels only penetrate about one third to one half of the meniscus.  Therefore, a tear of the meniscus may not be able to heal if it is in the “wrong” place.  Some tears may be in the “right” place (vascular zone), but the tissue has been too badly damaged to try to repair. Because of the poor blood supply to the meniscus and the kind of tears that commonly occur in the meniscus, most meniscal tears can’t heal. About 10% of all meniscal tears have a chance of healing. Of those 10%, only about 70-80% will actually eventually heal, even with surgical help. If a torn meniscus is not untreated, about 1-3% of knees may become asymptomatic. The other 97% of the meniscal tears will either not get better or will get worse.

Conservative Treatment

Immediately after the knee is injured, “RICE” (rest, ice, compression, and elevation) should be started. There is a lot of pain or the knee feels unstable, a cane, crutches, or walker should be used to help rest the knee. Otherwise, activities should be reduced. You can try Tylenol and/or Advil or Aleve may be used to help with pain and swelling. A brace or wrap may make the knee feel more stable. Ice and elevation will help minimize the swelling and pain. You should plan to see your doctor to help make the diagnosis.

If the pain is minimal, the there is no locking or instability, and your doctor has rule out other problems in your knee, you may choose to see how you knee will do. As mentioned above, a small percentage of patients with a meniscal tear may not have any problems with their activities. If the pain worsens or you have instability or locking in the knee, surgery will be needed. There are two options for the surgical treatment of the meniscal tear; to remove the torn part of the meniscus or to repair the meniscus.  The ultimate decision as to which treatment option is best for a given meniscus tear is made at the time of surgery.

Partial Meniscectomy: Removal of the torn part of the meniscus

When surgery to treat the meniscus has been decided on by yourself and your doctor, an arthroscopy will be performed. An arthroscopy is the surgery done by placing a small camera and instruments into the knee. The surgeon can look through the knee and determine the problems in the knee. The meniscal tear seen will determine the treatment needed. If the tear in the meniscus is in the central 2/3 of the meniscus, not in the vertical (up and down) orientation, complex in nature, or very old, the torn part of the meniscus (not the whole meniscus) will be removed.

The postoperative treatment after partial meniscectomy has three phases. There is some overlap of the phases and the amount of time of each phase will vary from one patient to another.

Phase I is the immediate post-operative reduction of swelling and pain.  Although full weight bearing (FWB) is allowed, your level of pain will dictate how much weight you can put on your leg.  The leg should be elevated and iced as often as possible and needed.  Pain medications will be taken as needed. 

Phase II begins as soon as the swelling and pain will allow (usually within 3-5 days).  This phase consists of regaining full range-of-motion (ROM) and strength.  This may take up to 3-6 weeks. 

Phase III is return to normal activities.  The time required for this phase will depend on many factors including, but not limited to, activities to be performed, pre-operative strength, and how hard you work at recovery.

**The meniscus that is left in the knee will still have to deal with the stresses in the knee and will be at risk for a tear just as the healthy meniscus was prior to its injury.  In other words, a tear can occur in the remaining meniscus.**

Meniscal Repair

A tear of the meniscus that occurs in the “vascular zone”, is vertical (up and down), and is healthy enough can be considered for a repair.  There are a number of ways to repair the meniscus and the technique chosen will depend on the type of tear, the location of the tear, and the size of the tear.  In all cases, the edges of the torn meniscus need to be “roughened up” to make sure the blood vessels can bring in the repair cells that have the potential to heal the torn meniscus.  Sometimes it is necessary to make another incision, a cut, in order to tie the sutures without causing nerve or blood vessel injury.  Even if everything goes well, there is only about a 75-80% chance of the meniscus healing.

After surgery, it will be very important to avoid putting any weight on the operated leg for at least three weeks or until your doctor gives you the okay.  Putting weight on the leg puts pressure on the meniscus that it may not be able to handle in the first few weeks of healing.  You should move your leg through a full range of motion as soon as you can to prevent excessive scarring and lose of motion.  Once you are allowed to put weight on your leg, you will be taught strengthening exercises and then progressed back to activities as tolerated.  The minimum recovery time will be around 8-9 weeks.

If after you have returned to normal activities you were to experience similar problems as before surgery, this would indicate that the meniscus has not healed or you have a new meniscus tear.  A second arthroscopy will need to be done and probably a partial meniscectomy will be performed.

Meniscal Transplant

In rare cases, the amount of the meniscus torn is very extensive and the meniscus has to be removed or a portion (greater than 1 cm) of the rim must be removed. When this happens, either the meniscus can’t function or there is no meniscus left to function. The loss of a functioning meniscus will lead to arthritis in the knee in 20-30 years (If there was a normal knee to start with.). If the patient without a functioning meniscus is young and active, a replacement of the meniscus may be considered. Presently, this is done by replacing the meniscus with an allograft (from a cadaver) meniscus. Your doctor will discuss this with you further if needed.

Written by James A. Shapiro, MD