MENISCAL INJURIES

Meniscal tears are one of the most frequently reported injuries to the knee joint. The meniscus is a C-shaped fibrocartilaginous structure in the knee incompletely covering the surface of the tibia where it articulates with the femur. There is a medial meniscus, on the inner part of the knee, and a lateral meniscus on the outer aspect of the knee.

The menisci act as shock absorbers protecting the articular surface of the tibia as well as assisting in stabilisation of the knee. As secondary stabilizers, the intact menisci interact with the stabilizing function of the ligaments and are most effective when the surrounding ligaments are intact.

The majority of the meniscus has very poor blood supply and for that reason, when damaged, the meniscus is unable to undergo normal healing and often requires surgical intervention to either remove torn tissue or to attempt surgical repair.

In addition, meniscal cartilage begins to deteriorate with age, often developing degenerative tears. Typically, when the meniscus is damaged, the torn pieces begin to move in an abnormal fashion inside the joint.

Menisci may tear because of the reasons described below:

·      Twisting motion

·      Over flexing the knee joint

·      Pivoting such as in sports activities

·      Sudden stopping or deceleration

·      Degenerative changes that occur over time which can weaken and thin the menisci resulting in          tears

Following a twisting type of injury, the medial or lateral meniscus can tear. This results either from a sporting injury or may occur from a simple twisting injury when getting out of a chair or rising from a squatting position. Our cartilage becomes brittle as we get older and, therefore, can tear more easily.

The symptoms of a meniscal tear include:

·      Pain over the inner or outer side of the knee where the tear occurred

·      A “popping” or "clicking" may be felt at the time of injury

·      Knee swelling, stiffness and ‘tightness’

·      Reduced range of motion

Locking can occur if the torn cartilage gets caught between the femur and tibia preventing straightening of the knee.

TREATMENT

Arthroscopic surgery to remove or repair torn menisci is the definitive treatment for meniscal tears. Torn menisci that do not cause the knee to catch or lock are less likely to cause damage to the rest of the knee and pain and swelling symptoms can be treated non-operatively with over the counter pain medications.

TREATMENT FOR NON-LOCKING MENISCAL TEARS

Initial treatment for non-locking torn menisci usually involves management of the pain and swelling symptoms with over the counter pain medications.

When a torn meniscus is diagnosed, but the knee is not locked and the patient cannot identify a specific incident associated with the onset of pain, the pain can be treated initially with over the counter pain medications such as paracetamol or ibuprofen. The patient should avoid pivoting and squatting and should work on keeping the quadriceps muscles strong. Physiotherapy canbe helpful in strengthening the quadriceps muscles.

If the swelling and pain have not resolved in 6 weeks, they usually won't without surgical intervention.

SURGERY

Keyhole surgery is the definitive treatment for torn meniscus. The surgery will include either removal or repair of the torn part of meniscus. Repair can be done only when the tear lies in or just adjacent to the zone of the meniscus that has a good blood supply.  Because only the outer 20-25% of the meniscus has blood supply, repairs are successful when the tear occurs in this vascular region of the meniscus. Tears in the non-vascular region are unlikely to heal and therefore are removed.

SURGERY FOR MENISCAL TEARS WITH ARTHRITIS

In the case of a degenerative meniscal tear associated with arthritis, the expected outcome after surgery is different. Although arthroscopically treating the torn meniscus and simultaneously trimming away any shaggy articular cartilage caused by the arthritis may eliminate mechanical symptoms such as catching or locking, the non-mechanical symptoms of osteoarthritis ( stiffness, achiness, weather-related pain) may persist.  Therefore, in the setting of a degenerative meniscal tear with osteoarthritis, the patient and doctor also need to discuss treatment alternatives for the arthritis such as injections into the knee or knee replacement.