Meniscus injuries (medial or lateral)

Meniscus, shaped as a letter C or a half moon, are positioned between the knee joint articulation surfaces, between the femur and tibia. They are made out of cartilage tissue and their purpose is to serve as amortization tools of the knee joint by making the joint surface bigger and serving as two cushions which decrease excessive joint capsule abrasion and withstanding the stress and loads put on the knee joint in daily activities.

There is an external or lateral and internal or medial meniscus (meniscus medialis i meniscus lateralis) and their primary purpose is knee joint stabilisation during movement performance as well as absorption of loads and forces that those movements put on the knee joint. The knee is built in such a way that its joint capsule is very shallow and flat which can be a risk factor and lead to the joint sliding in certain movements. The meniscus are the ones that prevent and decrease the risk of that happening.

Certain movements in the knee joint can cause injuries or damage on the meniscus and those movements are sudden, unexpected during which active knee stabilizers can not completely secure that stability leading to excessive stress and load being put on passive stabilizers (ligaments) and the joint capsule which is then transferred onto either one or both meniscus. Meniscus injuries or damage can be of smaller or bigger degree and they can also be accumulated by small damages and changes which during time result in a more serious problem. The main problem with meniscus injuries/damage is the fact that there is no real replacement for them, ie. when a point is reached where the level of injury/damage is so significant that the meniscus tissue can not regenerate or be successfully repaired through surgery, a cartilage tissue can develop in its place and take on its role, but it does not have the same qualities as the meniscal tissue itself.

Injuries or problems which can occur with meniscus are pinched meniscus where the meniscus gets moved or a part of it gets pinched between two joint surfaces resulting in knee movement limitations. Partial or complete meniscus ruptures where the surface of the meniscus, due to overload, excessive force or through accumulation of small changes through time, gets torn. Meniscus contusion with which a part or the whole meniscus can be pressured and bruised causing lesions and pain possibly leading to certain knee movements accentuating that pain and making the lesions bigger over time. Meniscus injuries/damage most often occur during rotations in the knee joint combined with knee extension or flexion. Often in these cases a biomechanically incorrect foot placement can be observed, ie. the foot, the knee and the hip are not aligned in one line during performance of the movement which leads to overloading either the lateral or the medial part of the knee segment and its structures during sudden and unexpected rotations in the knee. It should be stated that the lateral meniscus is more mobile out of the two and according to that it is injured/damaged less frequently. The lateral meniscus is not fixated to the lateral collateral ligament, which is the case with the medial meniscus and medial collateral ligament, therefore the lateral meniscus has more mobility in case of knee rotation, with the medial meniscus that mobility lacks and it leads to it being more frequently injured/damaged.

Treatment of meniscus injuries and damages can be conservative or surgical, depending on the type and level of injury/damage. Conservative treatment implies use of physical therapy methods in order to relieve pain and swelling caused by the damage or injury and to help the meniscus tissue heal faster and easier if it is possible depending on the extent of that injury or damage. Functional phase considers progressive strengthening of upper leg muscles and regaining of knee joint balance and stability. Surgical treatment depends on the type and extent of injury/damage and today it mostly implies an arthroscopic approach in order to maximally decrease scar tissue. Complete or partial meniscectomy  (removing a part or the whole meniscus) and meniscus stitching repair surgery are some of the most common surgical procedures done with meniscus injuries/damages. Due to the important role  of meniscus, after a complete meniscectomy, very often a transplant is being put in so that the knee joint could be kept functional for a longer period and excessive abrasion of its joint capsule would be prevented.

Prevention: maintaining a healthy weight, correct performance of movement which includes knee activity, with an added accent on foot, knee and hip positioning, preventive programs for upper leg strengthening and knee stabilization, etc.