A knee meniscal tear is one of the most common knee injuries. It is a common cause of knee pain. Men are typically affected in their 30’s and 40’s, and women in their 20’s. A degenerative tear can also occur with minor trauma such as getting up from a chair, especially in patients in their 50’s and 60’s. The meniscus is a c-shaped cartilage which acts like a “shock absorber”. It also provides stability, lubrication and position sense…
There are two such structures in each knee. One is on the inner aspect of the joint and one on the outer aspect. The meniscus has a poor blood supply for the most part, and this makes healing of injuries to the cartilage difficult. Injuries in the periphery of the tissue have better healing potential as the blood supply here is better.
Mechanism of Injury and Clinical Examination
Although trauma can result in an injury, occasionally there is no history of trauma. The cartilage may be torn by movements such as a sudden twist or repeated squatting. Sometimes you may not be able to recall the exact event. The usual complaint is that of pain which is mainly felt along the joint margins on the side of the knee.
Pain may be felt at the front or back of the knee depending on the nature and location of the tear. Often there is clicking, catching, locking, pinching or a sensation of “giving way”. The pain may be accompanied by intermittent swelling.
For further reading on possible signs of a meniscal tear please see this useful article: Three signs that you may have a torn cartilage in your knee (meniscal tear)
A thorough history and complete physical examination is needed to evaluate a patient who may have a meniscal tear. It is important to exclude other possible causes of the pain. The exact location of the tenderness, the presence or absence of fluid in the knee, and the range of motion are determined. The McMurray test may be positive. This involves putting the knee through a range of rotatory movements in flexion and extension to try and elicit the pain and/or click from a torn meniscus.
Cartilage cannot be seen directly on X-rays of the knee. X-rays are usually obtained, however, to exclude other possible causes for the pain such as a fracture or osteoarthritis. An MRI scan is a highly detailed scan which can image all the internal structures of the knee. This includes the meniscal cartilage and ligaments and may be used to help diagnose a tear.
In some instances it is possible for a person with a small tear in an area with good blood supply to heal without surgery. Such conservative management may include rest or activity modification, the use of anti-inflammatories, and physiotherapy.
Most tears, however, do not heal without intervention. The tear may progress and become more painful. It may even become dislodged from its normal position and cause a “locked” knee, where you are unable to fully straighten the leg. Unattended tears can be the cause of cartilage damage elsewhere in the knee. Eventually this may result in painful osteoarthritis of the joint.
The goal of surgery
The basic goal of surgery is to “save the meniscus”. A meniscal repair with stitches is performed if this is feasible. A number of factors are taken into account. These include age, activity level, type of tear and associated ligamentous injury. For non-repairable, complex tears and those in an area of poor blood supply, the torn part of the meniscus is removed (partial meniscectomy). The aim is to leave as much stable meniscal tissue as possible behind.
In the past, the operation would involve open surgery and make use of larger incisions to repair the injury. Today the procedure is safely and successfully carried out arthroscopically (using “keyhole surgery”). A high definition camera is used to inspect the joint, and repair or remove the torn meniscus.
The benefits of arthroscopy include smaller scars, improved vision, faster recovery and rehabilitation and better outcomes. Surgery is generally successful and gives a high level of patient satisfaction. However, in a person with an arthritic knee, arthroscopy may have more limited benefit.
The complication rate is quite low. Possible complications include infection, damage to blood vessels and nerves, and blood clots in the legs (DVT). Occasionally there may be bleeding into the joint, joint stiffness and persistent pain. Some attempted repairs may fail if the blood supply is poor. In the long term, the aim of a meniscal repair is to reduce the risk of developing osteoarthritis. The risk of this is higher if part of the meniscus had to be removed.
The recovery after surgery for a torn meniscus depends on the procedure that was performed. If a partial removal was performed, the recovery is usually faster. The patient can begin full weight bearing without any limitations on knee movement as soon as this is comfortable.
If a repair was performed, it is usually necessary to use crutches to avoid putting any weight on the leg. A brace is used to prevent excessive bending of the knee for about six weeks to allow the repair to heal. During this period and afterwards, physiotherapy is valuable. This is aimed at maintaining or improving muscle strength and range of motion.
Return to work is possible soon after surgery unless the occupation involves physical labour. Return to sport can be as soon as two to three weeks for a meniscectomy. It may take longer (six to eight weeks) for a repair.
Braking function returns to normal approximately four weeks after knee arthroscopy. Therefore, I do not recommend driving during this period if the right knee was operated on. Driving may be allowed earlier with the left knee. Patients should also not drive with a brace or if they need analgesics to operate the vehicle.
A meniscal tear is a common cause of pain in the knee. Therefore, those who have developed persistent pain, especially after an injury should visit their doctor for an assessment. An appropriate examination and investigations should be performed. The risk of delaying treatment could result in the development of an arthritic knee.
As an orthopaedic surgeon with a special interest in knee surgery, I see and treat many patients who have a meniscal tear. I treat patients at Waterfall Hospital in Waterfall/Midrand and Morningside Mediclinic in Sandton. I also treat patients from many other areas as well, including Rosebank, Sunninghill and Fourways.
Yours in good health,
Dr Warren Matthee
MB BCh (Wits), MRCS (England), MMed (Ortho Surg), FC Orth (SA)