Meniscus tears are common injuries affecting the knee, being prevalent in approximately 14% of the population. Dr Mithil Rambhojun, Orthopaedic Surgeon, gives us more insight into this condition and how it can be diagnosed and treated.
Each knee has two meniscii- medial (inner) and lateral (outer), which are attached on the tibia.
A meniscus is a smooth and soft structure made up of collagen whose main functions are acting as a shock absorber while also providing stability to the knee joint. It also helps in nutrition and lubrication of the cartilage end of the bones in the knee.
In doing so, the meniscus ensures protection against the forces that act on the knee during various activities of daily life and sports.
Some meniscus tears can be acute, resulting from an injury to the knee, while others might be part of the normal ageing process, termed as degenerative tears. Patients having the latter type are sometimes in their early 40’s and seldom remember any specific traumatic event. Symptoms associated with these tears are knee pain while standing/walking/impact activities, swelling of the knee especially after exercising, clicking/popping sounds and locking of the knee. They may also be associated with other symptoms of arthritis such as stiffness of the knee and in more severe cases, deformity of the knee (usually bending outwards).
Acute meniscus tears usually result from a twisting the knee, sudden vertical impact like landing from a jump or vigorous running, especially on uneven ground. The knee becomes painful and swollen within hours of the injury and some types of tear result in a mechanical blockage, causing the knee to be locked in a certain position.
A history and thorough clinical examination usually elicit signs pointing to the injury. Although meniscus is not seen on x-rays, they can give clues to the diagnosis such as decreased joint space and abnormalities in knee alignment that may be a predisposing factor for meniscus tears.
MRI scan is the preferred modality for diagnosis of meniscus tears although some types still remain elusive and are visualized during an arthroscopy.
Initial treatment is RICE - Rest, Ice, Compression and Elevation. The knee can also be temporarily immobilised in a brace if the pain and swelling are severe. If symptoms do not subside, consultation with a doctor is imperative.
The decision to operate depends on several factors - the type and duration of the tear, patient factors, activity levels, whether the tear is associated with other injuries and presence of mechanical symptoms like locking/pain which are not relieved by initial measures.
Meniscal surgeries are done arthroscopically, i.e. using a small camera to directly visualise the joint and treat the injury using special instruments and sutures. For some small or degenerative tears, as well as those having poor healing potential, a simple arthroscopic shaving and smoothening of the edges of the tear can provide significant relief.
The advantage of arthroscopy is that it can assess and treat other concomitant injuries such as cruciate ligament and cartilage lesions.
In some countries having human tissue bank, whole meniscus transplants are done in young, active individuals who have suffered extensive meniscus injuries which are beyond repair.
Some tears can lead to instability (feeling of the knee ‘giving way’) and recurrent joint effusion (accumulation of fluid in the joint). Chronic pain resulting from an untreated tear causes muscles around the knee to weaken and the lack of cushioning effect in a torn meniscus may lead to early arthritis of the knee.
