Introduction
The knee joint is one of the largest and the most complex joint in the body. The knee is most susceptible to trauma as it is used more often. The joint is made up of the femur (thigh bone), the tibia (shin bone), and patella (kneecap). Between the femur and the tibia lie two wedge-shaped pads of cartilaginous tissue called menisci, which serve to reduce friction in the joint as well as act as shock absorbers. The two menisci present in the knee are the lateral meniscus on the outside and medial meniscus on the inside of the knee.
Function
The meniscus helps in even distribution of the body weight across the knee joint. As the substance is tough and rubbery it cushions the joint and keeps it stable. It also protects the articular surface of the tibia and assists in rotation of the knee. As secondary stabilizers, the intact menisci interact with the stabilizing function of the ligaments and are most effective when the surrounding ligaments are intact.
History of Injury
Meniscal tears are one of the most frequently reported injuries to the knee joint. Meniscal injuries occur when upper leg is rotated or twisted without moving the foot. Sudden meniscal tear occurs among athletes, especially those involved in contact sports. During sports activities, you may suddenly bend or twist your knee causing the meniscus to tear. This is a traumatic meniscus tear. Elderly people are more prone to degenerative meniscal tears as the cartilage wears out and weakens with age.
Most parts of the meniscus have no blood supply and because of this reason the damaged meniscus is unable to undergo the normal healing process that occurs in the rest of the body. Typically, when the meniscus is damaged, the torn pieces begin to move in an abnormal fashion inside the joint. The symptoms of a meniscal tear include pain over the inner or outer side of the knee where the tear occurred, swelling, stiffness and tightness over the knee, and reduced range of motion.
Diagnosis
The source of knee pain should be evaluated to determine the treatment options for pain relief. Depending on the medical history and physical examination, your doctor may order diagnostic tests such as X-ray and MRI scan to rule out other conditions. An X-ray can reveal if osteoarthritis from degenerative changes is causing your knee pain. The menisci can be viewed on MRI to assess for injury.
Treatment
Initial: Immediately following a knee injury, you should initiate RICE method of treatment. Rest the knee as more damage could result from putting pressure on the injury. Ice packs can be applied to the affected area for 15-20 minutes four times a day for several days. This helps to reduce swelling and pain. Wrap your with an elastic bandage or compression stocking to minimize swelling and support your knee. Keep your leg in a elevated position above the heart level to reduce swelling.
Long term: Anti-inflammatory medications may be prescribed to reduce pain and swelling. You may need crutches temporarily to assist in limiting weight bearing. Physical therapy may be recommended for muscle and joint strengthening. Immobilizers such as a soft brace may be applied to the knee to keep the joint stable.
Indications for surgery
Your surgeon may recommend surgery if the conservative treatment options fail to relieve your knee pain or if your knee continues to lock and is not healing. Surgical treatment options will depend on the type of tear, location and extent of the tear.
Surgery
Meniscus Repair
Meniscal repair is essential when the torn meniscus does not heal on its own even after the patient has rested and restricted movement of the damaged part of the knee using a brace. Meniscal repair depends on extent of tear and the blood supply to the region. Arthroscopic surgery is often preferred as it minimizes knee damage promotes complete recovery. A torn meniscus will be evaluated for the possibility of repair. Often, surgeons prefer meniscal repair because it decreases osteoarthritic changes and the impact on sports activity in the long-term as compared to partial meniscectomy.
Meniscal repair involves the use of sutures or implants to reduce and fix the meniscal tear through an arthroscopic procedure. These procedures may require the use of extra incisions to safely repair the meniscus.
The goal is to repair any meniscal tear if appropriate. If the tear is not repairable then partial meniscectomy will be recommended.
Partial Meniscectomy
Partial meniscectomy is a surgical procedure to remove the torn portion of the meniscus from the knee joint. In total meniscectomy the entire meniscus is removed, but in partial meniscectomy your surgeon will only remove the torn meniscus. Total meniscectomy will help in relieving symptoms, but because the entire meniscus is removed; the cushioning and stability between the joints will be lost. Hence partial meniscectomy is considered.
Partial meniscectomy is performed with arthroscopy, where several small incisions are made around the knee. Through one of the small incision, a miniature camera is inserted to see inside of the knee. Tiny surgical instruments are inserted through other small incisions to repair the tear. During the procedure the torn meniscus is removed and the remaining edges of the meniscus are smoothened so that there are no sharp ends. Any unstable fragments which are causing locking and catching sensation will also be removed.
Partial meniscectomy helps in restoring or maintaining knee stability and offers faster and complete recovery. After surgery rehabilitation exercises may help to restore knee mobility, strength and to improve range of motion.
Possible risks and complications of partial meniscectomy include infection, bleeding, and injury to blood vessels or nerves.
Meniscus Transplantation
Patients with significant loss of their meniscal cartilage due to trauma or multiple arthroscopic trimmings of the meniscus may experience symptoms due to the loss of this tissue. A meniscal transplant uses a size-matched cadaver meniscus to replace the damaged meniscus in an effort to alleviate pain, improve function and preserve the joint.
Preserving the Meniscus
At the Rush CRC® we do everything possible to repair or even replace torn meniscal cartilage. In the past, the first line of treatment for such injuries was complete removal of the meniscus. However, many people who have had this protective cartilage removed during a procedure called a meniscectomy, have developed arthritis very early in life. Today, experts recognize the protective value of meniscal cartilage. To preserve meniscal function after injury, surgeons repair the meniscus whenever possible, removing only the portions that are considered irreparable.
Restoring the Meniscus
An investigational technique called a meniscus implant is used for patients who have sustained recent meniscus tears, those which cannot be repaired, or who have already had part of the meniscus removed. The Rush CRC is participating in a meniscus implant investigational study along with a handful of other medical centers. Collagen implants are designed to provide a biocompatible and bioresorbable bridge for tissue growth when implanted in the body.
To restore meniscal function following meniscectomy, surgeons can sew a collagen meniscus implant into the area where meniscus tissue is missing. Over time, the implant is replaced by the body’s own meniscus cells and is naturally resorbed, leaving new meniscus tissue in its place.
Replacing the Meniscus—The Cutting Edge
For patients who have had the meniscus completely removed in a previous surgery, the Rush CRC offers an innovative solution called a meniscus transplant. Using this technique, surgeons transplant donated meniscus cartilage—which has been tested to ensure that it is free of any transmittable disease—to replace cartilage that has been removed in a previous surgery. Unlike other forms of tissue transplantation, this procedure does not require patients to be on medication to prevent tissue rejection.
To replace meniscus cartilage that was previously removed, surgeons can arthroscopically, through small incisions, sew in a meniscus transplant that heals and functions much like the patient’s own meniscus. This leads to a more stable and less painful knee that might otherwise have developed progressive arthritis.
Doctors at the Rush CRC expect that these new methods will help stave off the development or progression of arthritis, and possibly eliminate the need for later surgeries.