What is a Meniscus?
A meniscus (plural= menisci) is a special kind of tissue that acts as a cushion inside the knee joint. There are two menisci or cushions in each knee joint- one in the inner half of the knee joint (called the medial meniscus) and one in the outer half (called the lateral meniscus). These cushions distribute the load acting on the knee joint more uniformly across the surface of the joint.
What happens if the meniscus is torn or absent?
If this cushion is absent, torn or is removed, the uniform distribution of load does not occur, and this will considerably increase the force acting per unit area or the pressure on the knee joint surface. This can hasten the development of age-related changes in the knee joint (also called “osteoarthritis”). In addition, torn fragments of the meniscus can interfere with the normal functioning of the knee joint and may cause symptoms like clicking sounds, locking of the knee joint, sudden catching, instability etc.
How does a meniscus get Torn?
A tear in the meniscus can occur for many reasons. One of them is a twisting injury. This twisting injury may occur during sports and dancing, or may simply occur during normal activities like climbing stairs, walking on uneven surfaces, squatting, etc. In many cases, either there is no specific injury event or the patient does not remember any specific incident, and the tears may develop during normal usage of the knee joint. Meniscal tears may also occur as part of the. normal age related wear and tear of the knee joint, when they are called degenerative tears.
What are the treatment options for meniscal tears?
Options include:
- Partial removal (meniscectomy)
- Meniscus repair
- Meniscus transplant.
Meniscal tears can be of many types, and different types of meniscal tears require different treatments. Some tears are best left alone, whereas other tears require repair. Some require removal of the torn part from the knee joint (called “partial meniscectomy”).
It may be noted that after tear or removal, the meniscal tissue cannot grow back. Hence, after a meniscectomy, the meniscus may not return to its completely normal level of function. That is why, wherever possible, preserving the meniscus and repairing it is advisable. Having said that, in many cases, the tears are not amenable to repair, and they require that the torn part be removed from the knee joint (“partial meniscectomy”). Although this will not bring the meniscus to its normal condition, however, atleast the joint surface will not suffer direct damage from the torn piece, and balancing of the torn edges may also decrease chances of tear progression. When the damaged or torn tissue involves almost the whole of the meniscus (called subtotal meniscectomy), it may require a “meniscus transplant”, either using the patient’s own tissues or using tissues harvested from human bodies.
The treatment of the meniscal tear depends on which meniscus is involved (medial or lateral) or which part of the meniscus is involved, like the root (the part that attaches the meniscus to the bone), the horn, the body, etc. This also depends on the shape of the tea, like flap tear, radial tear, longitudinal tear, complex tear, etc., and the exact location of the tear, such as central location, peripheral location, etc. Many other factors influence the treatment options for a meniscal tear like the quality of the meniscal tissue, how old the tear is, the age of the patient, the physical demands and requirements of the patient. Your treating arthroscopic surgeon will evaluate your knee as well as the pattern of tear visible on the MRI and will take into consideration all the various factors to decide the best treatment plan for you. Meniscal repairs are best performed by a dedicated arthroscopic surgeon.
How is a meniscus tear diagnosed?
Your treating doctor may suspect a meniscus tear based on history and examination of your knee. MRI scans are used to diagnose meniscal tears. However, MRI is not 100% sensitive and specific, and the gold standard method for detecting meniscal tears is by directly seeing the meniscus inside the joint through a keyhole surgery (arthroscopic surgery). In some cases, Where MRI suggests a complete tear, it is found on arthroscopy that there is no significant Tear. On the other hand, in some cases, the MRI fails to detect a tear, whereas on arthroscopy, a tear is found in the meniscus. Further, while MRI gives an idea about the location, size and type of the tear and the quality of the meniscus tissue, however, the exact pattern of the tear and the tissue quality can be judged only after seeing it directly during the arthroscopic surgery. Hence, an MRI can only help determine a general treatment plan. Whether a meniscal tear can be repaired or it requires removal of the torn portion can be exactly determined only during the arthroscopic surgery itself.
“Meniscus transplant or replacement” is the surgery for creating a new meniscus in the knee joint, either using the patient’s own tissues or using tissues harvested from human bodies. Using arthroscopic surgery, this is then inserted inside the joint through a key hole and fixed in the place of the absent meniscus using multiple fixation devices. This is a highly specialised surgery and for this, you should consult a dedicated arthroscopic surgeon who has experience in performing such surgeries.
