Meniscal Tears

  • A healthy knee contains two C-shaped cartilage structures. The one on the inside is called the medial meniscus and the one on the outside is called the lateral meniscus. Each meniscus is smooth, rubbery, and flexible and acts to provide stability and shock absorption to protect the joint cartilage. Any loss or damage to the joint cartilage is called arthritis. A tear of the meniscus is called a meniscal tear.

  • The meniscus is divided into three parts. The outer part is vascularized (supplied by blood) and is called the red zone. A tear here can be repaired with sutures. The middle part has some vascularity and is called the red-white zone. A tear here can be repaired with sutures in some younger patients. The inner part is not vascularized and is called the white zone. A tear here can only be removed.

    A bucket handle tear is a large tear of the meniscus that will result in swelling and locking as the tear gets stuck in the joint. These will require surgery to restore knee function. A flap tear can cause swelling and locking if the torn piece is large enough. Degenerative tears can often be treated without surgery. These are often frayed meniscus tissue which can irritate the knee. They do not heal but they can calm down and become less symptomatic on their own or with treatment.

  • An acute meniscal tear occurs from a twisting knee injury. In younger patients this is often a sports or sports type twisting injury. Older patients can also have large twisting injuries but can often have a subtle twisting injury that results in a meniscal tear. Degenerative or Chronic meniscal tears often occur in middle aged patients. These are the result of wear and tear over the years. Often a minor injury can make these tears symptomatic.

  • Patients will have pain on the medial or lateral joint line of the knee. They will often have swelling which can be delayed several hours after a twisting injury. Larger tears may have clicking or locking at the joint line. Be aware that most clicking in the knee occurs between the kneecap and the femur and is not related to the meniscus.

  • an effusion (fluid in the knee) and tenderness at the joint line is common in meniscal tears but is also common in arthritis. Other provocative tests which basically move or gently twist the knee and cause pain or locking can help confirm the diagnosis.

  • 1.An X Ray does not show the meniscus but it is always the first test ordered when a meniscal tear is suspected. In young patients a meniscal tear is a forceful injury and a fracture of the bone needs to be ruled out. In an older or middle aged patient the degree of arthritis needs to be assessed. There are degrees of arthritis where it can be assumed the patient has degenerative meniscal tears. There are further degrees of arthritis where a meniscus tear does not affect the treatment and all treatment is directed towards the arthritis.

    2. An MRI will show the meniscus and is the most sensitive test to confirm a meniscal tear. They are very accurate in confirming large tears. They have a high false positive rate for diagnosing small tears. This means they show a tear when one is not there. For this reason it is important for the history, the exam, and the MRI all align to confirm the diagnosis.

The Basics

  • Rest, anti Inflammatory medicines, early gentle motion, and physical therapy are often effective in smaller meniscal tears and degenerative tears. Patients with arthritis and a suspected meniscal tear will often improve with a cortisone injection. There is no indication to do preventive surgery on asymptomatic meniscal tears. A small tear can get bigger with a twisting injury but a normal meniscus and a postoperative meniscus can tear as well. Larger tears will usually not respond to medicine, early motion, physical therapy, or injections and will often require surgery. If the tear is large enough to cause locking the patient will often have surgery as soon as possible. Irritating but not locking tears can often be treated with activity modification until a convenient time to have surgery.

  • The majority of patients requiring surgery have arthroscopic surgery to address the meniscal tear. The patient will need preoperative medical clearance and can not eat or drink after midnight the eve of the surgery. The surgery is an outpatient surgery meaning the patient goes home the same day. The surgery is often done with sedation and a regional anesthesia (the anesthesiologist gives a numbing shot around the nerves to make the knee numb). 2-3 poke holes are placed in the knee. A camera the size of a pencil is used to look around the knee. Shavers and biters are used to perform a partial meniscectomy. This means the torn part of the meniscus is removed but the surgeon leaves as much healthy meniscus as possible. The down side is the patient could tear the meniscus again in the future. The upside to saving as much meniscus as possible as opposed to removing the entire meniscus is that the healthy meniscus helps prevent arthritis. After surgery the knee is wrapped in an ace bandage. The patient can walk with or without crutches. Gentle motion exercises are started. The bandage is removed 4 days after surgery. Most patients can resume normal activities in 2 weeks but should not start athletic type activities for 6 weeks.

    A tear in the periphery (red zone) of the meniscus can often be repaired with sutures to salvage the entire meniscus. This type of tear usually occurs in younger patients (under 25 years old). Many will be non-weight bearing on crutches for several weeks and will require physical therapy after surgery. It is a longer recovery but retaining the meniscus helps prevent arthritis in the future.

    Results - An isolated meniscal tear where the rest of the knee is healthy will have an excellent recovery in the vast majority of patients. In patients with severe arthritis arthroscopic surgery will not be helpful. Surgery is less predictable in patients with some arthritis and a meniscal tear. The surgery is partly a diagnostic procedure. The X Rays, MRI, and physical exam are helpful but nothing is as accurate as arthroscopy for looking and probing the joint cartilage and meniscus. If the meniscal tear is smaller than expected and the arthritis ( damage to joint cartilage) is worse than expected the patient will not get much benefit from arthroscopic surgery. They will need further arthritis treatment to get relief. Often surgeons will clean out some arthritic changes such as removing loose or hanging joint cartilage . This may give some temporary relief but does not restore normal cartilage.

Treatment

Prevention

1. Acute meniscal tears- Ultimately some knee twisting injuries can not be avoided. That said, being well conditioned can help you decrease the chance of having a twisting knee injury doing routine activities. This means working to maintain your ideal weight, working to maintain or improve leg strength and flexibility, and working to maintain or improve balance and agility can all help to decrease your likelihood of suffering a twisting knee injury and meniscal tear. 

2. Chronic or degenerative meniscal tears- These are symptomatic due to inflammation and are therefore another disease of chronic inflammation. You may hear me say that there are people out running marathons or playing in the NFL with knees that look like yours. We often see MRIs of patients with degenerative meniscal tears who have no symptoms at all. Being the correct weight with strong and flexible legs will make some meniscal tears less symptomatic. Also addressing your body's overall level of chronic inflammation by improving your fitness, diet, sleep, and stress will be helpful in preventing symptomatic meniscal tears or helping you recover from symptomatic meniscal tears without surgery.