What is a meniscal (cartilage) tear?
A meniscal injury refers to a tear of the shock absorbing cartilage which lines both sides of the knee joint. The most common symptom is “locking” of the joint.
Knee meniscal injuries can occur in two ways.
In younger individuals, the menisci can be torn when playing sports requiring rapid changes of direction such as football, rugby or netball.
Middle aged or older individuals may have some areas of degeneration in their menisci. As such the menisci can suffer a tear with more innocuous activities such as when walking or climbing stairs.
The menisci of the knee are two crescent-shaped structures which sit on the knee joint surface of the lower leg bone (tibia). The medial meniscus sits on the inner aspect of the joint and the lateral meniscus sits on the outer aspect of the joint. Both menisci are constructed from strong soft tissue known as fibrocartilage and provide several important functions to the knee including:
- Providing cushioning to reduce forces within the knee joint
- Increasing joint surface area (further reducing relative forces within the knee joint)
- Increasing knee joint stability by moving backwards and forwards with the knee as it is flexed, extended or rotated
At the time of injury. Pain and a delayed onset of swelling (not immediate) of the knee. Depending on whether the medial or the lateral meniscus is injured, the pain will be localised to the inner or outer aspect of the knee respectively.
Ongoing symptoms. Pain and swelling will often improve over the course of a few weeks but complete recovery from symptoms may be prolonged. Regular activity and strengthening exercises of the knee can ease symptoms.
The classic symptom of a meniscal tear is locking of the knee joint. This involves the knee becoming stuck in a flexed position requiring the individual to manoeuvre the knee to “unlock” the joint. Lesser symptoms may involve “catching” or “clicking” often with associated pain. While “giving way” is not a classic symptom it can occur when associated with pain.
Ongoing symptoms may also occur with walking and heavier impact activities such as jogging, running or sports requiring rapid changes of direction.
How are knee meniscal tears diagnosed?
Knee meniscal tears can be diagnosed by your doctor or physiotherapist by taking a history of your condition and by conducting a physical examination.
The main feature on examination is tenderness directly over the joint line. Other physical tests may help in confirming the diagnosis.
X-rays or MRI scans are not routinely required, but may be requested if symptoms are ongoing, limiting normal activity and surgery is being considered.
How are knee meniscal injuries treated?
In the majority of cases, particularly in the older age group, meniscal injuries can be managed effectively by exercises designed to maintain flexibility and strength to the knee joint as described below.
Regular exercises to maintain flexibility and strength to the affected knee joint:
5×30 second holds, 2x per day
3-4 sets of 10 reps, 3-4x per week
3-4 sets of 10 reps, 3-4x per week
Corticosteroid injection therapy
For individuals who have trialled a course of supervised exercises, a corticosteroid injection may occasionally be offered as a treatment, where there are significant age-related changes to the meniscus or knee joint. You can read more about local corticosteroid injections here. Corticosteroid injections are not normally offered for individuals with mechanical symptoms such as locking.
Arthroscopic (keyhole) surgery may be an effective option for patients who:
- Have trialled a course of non-surgical management without success
- Have pain which limits walking distances or a return to normal sporting activities
- Have a satisfactory Body Mass Index (BMI) or have made lifestyle changes to lose excess bodyweight
In a few cases where the knee becomes “locked”, an urgent arthroscopy will be offered as the first line of treatment.
Please note that there is evidence to indicate that undergoing a knee arthroscopy will increase the risk of requiring a knee replacement in the future. Therefore, a decision on whether to proceed with surgery should only be taken on the basis of current symptoms and limitations.