One of the most commonly injured parts of the knee, the meniscus is a wedge-like rubbery cushion where the major bones of your leg connect. Meniscal cartilage curves like the letter "C" at the inside and outside of each knee. A strong stabilizing tissue, the meniscus helps the knee joint carry weight, glide and turn in many directions. It also keeps your femur (thighbone) and tibia (shinbone) from grinding against each other.
Football players and others in contact sports may tear the meniscus by twisting the knee, pivoting, cutting or decelerating. In athletes, meniscal tears often happen in combination with other injuries such as a torn ACL (anterior cruciate ligament). Older people can injure the meniscus without any trauma as the cartilage weakens and wears thin over time, setting the stage for a degenerative tear.
Signs and symptoms
You might experience a "popping" sensation when you tear the meniscus. Most people can still walk on the injured knee and many athletes keep playing. When symptoms of inflammation set in, your knee feels painful and tight. For several days you have:
- Stiffness and swelling.
- Tenderness in the joint line.
- Collection of fluid ("water on the knee").
Without treatment, a fragment of the meniscus may loosen and drift into the joint, causing it to slip, pop or lock-your knee gets stuck, often at a 45-degree angle, until you manually move or otherwise manipulate it. If you think you have a meniscal tear, see your doctor right away for diagnosis and individualized treatment.
Tell your doctor exactly what happened and when. He or she may conduct physical testing to evaluate the extent of your meniscal tear. You may need X-rays to rule out osteoarthritis or other possible causes of your knee pain. Sometimes your doctor may use a magnetic resonance imaging scan to get a better look at the soft tissues of your knee joint. Your doctor may also use a miniature telescope (arthroscope) to see into your knee joint, especially if your knee locks.
Menisci tear in a number of different ways:
- Young athletes often get longitudinal or "bucket handle" tears if the femur and tibia trap the meniscus when the knee turns.
- Less commonly, young athletes get a combination of tears called radial or "parrot beak" in which the meniscus splits in two directions due to repetitive stress activities such as running.
- In older people, cartilage degeneration that starts at the inner edge causes a horizontal tear as it works its way back.
Initial treatment of a meniscal tear follows the basic RICE formula: rest, ice, compression and elevation, combined with nonsteroidal anti-inflammatory medications for pain. If your knee is stable and does not lock, this conservative treatment may be all you need. Blood vessels feed the outer edges of the meniscus, giving that part the potential to heal on its own. Small tears on the outer edges often heal themselves with rest.
If your meniscal tear does not heal on its own and your knee becomes painful, stiff or locked, you may need surgical repair. Depending upon the type of tear, whether you also have an injured ACL, your age and other factors, your doctor may use an arthroscope to trim off damaged pieces of cartilage.
A cast or brace immobilizes your knee after surgery. You must complete a course of rehabilitation exercises before gradually resuming your activity.
Osteochondritis dissecans (OCD) is a disorder in which a fragment of cartilage and subchondral bone separates from an articular surface. The etiology is uncertain, although trauma and ischemia have been implicated. The knee is most commonly affected, but the elbow and ankle may also be involved. Patients typically present during their adolescent or early adult years with nonspecific knee pain and swelling that worsens with activity. The diagnosis is confirmed by radiographic findings. Management decisions are based on the patient's age and the stability, location, and size of the lesion.
The reported prevalence of OCD is 30 to 60 cases per 100,000 people. Patients usually present in their teenage years (those who have OCD of the patella usually present in their 20s and 30s), but the disorder may manifest later in life. It has been estimated that 4% of all cases of osteoarthritis of the knee diagnosed in men were the direct result of OCD. However, the lesion is not always symptomatic and is sometimes an incidental radiographic finding. Bilateral disease is present in 30% to 40% of patients. Males are affected three times more often than females.
If spontaneous healing doesn't occur, cartilage eventually separates from the diseased bone and a fragment breaks loose into the knee joint, causing locking of the joint, weakness, and sharp pain. An x ray, MRI, or arthroscopy can determine the condition of the cartilage and be used to diagnose osteochondritis dissecans.
If cartilage fragments have not broken loose, a surgeon may fix them in place with pins or screws that are sunk into the cartilage to stimulate a new blood supply. If fragments are loose, the surgeon may scrape down the cavity to reach fresh bone and add a bone graft and fix the fragments in position. Fragments that cannot be mended are removed, and the cavity is drilled or scraped to stimulate new growth of cartilage. Research is currently being done to assess the use of cartilage cell transplants and other tissues to treat this disorder.
Knee ligament treatment options
Ligaments connect one bone to another within a joint and help to provide stability and flexibility. There are four main ligaments in the knee. Injury to each one has slightly different symptoms and treatment. It is possible to damage more than one ligament in the same incident.
The medial collateral ligament is located on the inside of the knee and is taut when the leg is straightened. It is a strong ligament but can be sprained or completely torn (ruptured) when the straightened leg is twisted at the same time as being knocked sidewards. This can be during a contact sport, as with a football tackle, or without contact, as can happen in a fall while skiing. The injured knee is painful and swollen, especially on the medial (inner) side. By examining the knee and seeing how much the lower leg can be moved outwards, while the upper leg is held still, doctors can usually establish how badly the ligament is sprained. Grade I (a sprain) and grade II (partial tear) injuries of the ligament, are more painful than a complete (grade III) tear. Many grade I or II sprains will heal by themselves. A grade III tear usually requires surgery.
The anterior cruciate ligament (ACL) joins the back of the inside of the thighbone to the outside front of the shinbone. Cruciate means in the form of a cross. The ACL is so called because it crosses the posterior cruciate ligament.
The ACL is about half the strength of the medial collateral ligament and is the most commonly injured ligament in sport. Players of football, and other sports that involve running, jumping and landing, are prone to ACL tears or ruptures.
When the ACL is completely ruptured, it is common to hear a distinct popping sound. You may also feel something snap inside the knee. If the knee appears loose, it is usually a sign of an ACL injury. Other symptoms include:
- pain and tenderness
- almost immediate swelling
- ;an unstable knee, making it difficult to walk
- the knee locking during movement
A doctor tests for an ACL injury by pulling the lower leg forward while holding the thigh still. Treatment depends on how badly the knee is affected by the loss of the ligament and whether this prevents you from doing sport. If you do not ask a lot of your knee, you may not need to have it repaired. Others may need a reconstruction operation, which usually involves taking a graft of tendon (usually from the kneecap) to replace the lost ligament. Intensive physiotherapy to strengthen the thigh muscles (quadriceps) is necessary as part of a programme of rehabilitation.
The posterior cruciate ligament (PCL) joins the inside of the end of the thighbone to the back (posterior) of the shinbone. With the ACL, it forms a cross-shape. Also like the ACL, it helps to stabilise the front to back knee movements. The PCL is stronger than the ACL and therefore less prone to injury. The symptoms of a sprain may be milder than for an ACL injury, with no popping sound. For a suspected PCL injury, your doctor may ask you to lie on your back then raise your legs so that your thighs point straight up, with your knees bent at right angles. If your lower leg sags toward the floor, the PCL is probably torn. Other symptoms of a PCL injury are similar to those in ACL injuries. Less severe injuries can treated by strengthening the thigh muscles. Surgery is often recommended, especially for younger patients.
The lateral collateral ligament is on the outside of the knee. It is rarely injured on its own but may need to be surgically repaired at the same time as other ligaments. Damage to this ligament causes pain and swelling on the outside edge of the knee. In addition to a complete medical history and physical examination, diagnostic procedures for a knee ligament injury may include the following:
- x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body; can often determine damage or disease in a surrounding ligament or muscle.
- computed tomography scan (Also called a CT or CAT scan.) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- arthroscopy - a minimally-invasive diagnostic and treatment procedure used for conditions of a joint. This procedure uses a small, lighted, optic tube (arthroscope) which is inserted into the joint through a small incision in the joint. Images of the inside of the joint are projected onto a screen; used to evaluate any degenerative and/or arthritic changes in the joint; to detect bone diseases and tumors; to determine the cause of bone pain and inflammation.
- radionuclide bone scan - a nuclear imaging technique that uses a very small amount of radioactive material, which is injected into the patient's bloodstream to be detected by a scanner. This test shows blood flow to the bone and cell activity within the bone.
Specific treatment for a knee ligament injury will be determined by your physician based on:
- your age, overall health, and medical history
- extent of the injury
- your tolerance for specific medications, procedures, and therapies
- expectation for the course of the injury
- your opinion or preference
Treatment may include:
- muscle-strengthening exercises
- protective knee brace (for use during exercise)
- ice pack application (to reduce swelling)
Also called Knee scope - arthroscopic lateral retinacular release; Synovectomy; Patellar debridement
Knee arthroscopy is surgical procedure in which a small camera is used to examine tissues inside the knee joint. Additional instruments may be inserted to repair the knee.
Arthroscopic surgery on the knee involves inserting a small camera, less than 1/4 inch in diameter, into the knee joint through a small incision. The camera is attached to a video monitor which the surgeon uses to see inside the knee. In some facilities, the patient can choose to watch the surgery on the monitor as well.
For a simple surgical procedure, a local or regional anesthetic is administered, which numbs the affected area. The patient remains awake and able to respond. For more extensive surgery, general anesthesia may be used. In this case the patient is unconscious and pain-free. After the camera is inserted, saline is pumped in under pressure to expand the joint and to help control bleeding. Some surgeons also use a tourniquet to prevent bleeding.
After looking around the entire knee for problem areas, the surgeon will usually make 1-4 additional small incisions to insert other instruments. Commonly used instruments include a blunt hook to pull on various tissues, a shaver to remove damaged or unwanted soft tissues, and a burr to remove bone. A heat probe may also be used to remove inflammation (synovitis) in the joint.
At the completion of the surgery, the saline is drained from the knee, the incisions closed, and a dressing applied. Many surgeons take pictures of the procedure from the video monitor to allow the patient to see what was done.
Arthroscopy may be recommended for knee problems, such as:
- A torn meniscus (either repair or remove)
- Mild arthritis
- Loose bodies (small pieces of broken cartilage) in the knee joint
- A torn or damaged anterior cruciate or posterior cruciate ligament
- Inflamed or damaged lining of the joint (synovium)
- Misalignment of the knee cap (patella) The risks for any anesthesia are:
- Allergic reactions to medications
- Problems breathing The risks for any surgery are:
- Infection Additional risks include:
- Bleeding into the joint (hemarthrosis)
- Damage to the cartilage, meniscus, or ligaments in the knee
- Failure of the surgery to relieve symptoms
- Knee stiffness
Use of arthroscopy has reduced the need to surgically open the knee joint. This has resulted in less pain and stiffness, fewer complications, decreased length (if any) of hospitalization, and faster recovery time. Expectations vary widely with the indication for the surgery.
Surgery done for a meniscal tear or loose bodies when the patient has no other problems (like arthritis) is usually uncomplicated, and most patients can expect a full recovery. The presence of arthritis dramatically reduces the effectiveness of arthroscopy and up to 50% of patients may not improve post-operatively.
Arthroscopic removal of the synovium (arthroscopic synovectomy) can be of great benefit to patients with rheumatoid arthritis. Arthroscopic or arthroscopic-assisted surgery done to repair the meniscus or reconstruct ligaments in the knee is much more complicated with prolonged recovery and more variable results.
For a simple meniscal cleaning (debridement), recovery is usually quite rapid. The patient may need to use crutches for a while to reduce weight placed on the knee joint to control pain. Pain can be managed with medications. For more complicated procedures where anything is fixed or reconstructed, patients may not be able to walk on the knee for several weeks, and the overall recovery may be anywhere from several months to a year.