We so often see it on a football pitch or a basketball court. A player plants a foot, twists and goes down grabbing a knee. The problem more often than not is tearing of the meniscus (cartilage) or ACL (anterior cruciate ligament). Both can be extremely painful and require months of recovery.

Knee injuries -- like fractures, dislocations, sprains and ligament tears – are some of the most common injuries among athletes and common people alike. The knee joint is the largest and most complex joint in the body, bearing more weight than most other joints, making it more vulnerable to injury.

Research shows that women are more prone to knee injuries than men. In fact, female athletes are two to eight times more likely to suffer an ACL injury than their male counterparts.

ACL injuries

The ACL, one of the four primary ligaments in the knee, crosses the posterior cruciate ligament (PCL) in the centre of the knee. The ACL connects the front of the shinbone to the back of the thighbone, preventing the shinbone from sliding forward.

ACL damage, like a sprain or a tear, is the most common knee injury. Although the ACL can be injured by a direct blow to the knee, most ACL injuries are actually non-contact ones. They are often caused by a sudden change in direction or hyper-extension on landing from a jump. ACL tears are common in agility sports like football, volleyball, skiing and basketball.

ACL injuries usually need surgical repair through the construction of a new ligament of tissue harvested from one of the tendons around the knee. The rehab period from an ACL injury could range between six weeks and six months, depending on the extent of the injury.

MCL injuries

The medial collateral ligament (MCL) is another of the four primary ligaments in the knee. The MCL runs down the inner part of the knee, from the thighbone to the shinbone. Its primary function is to prevent an inward overextension of the knee. The MCL also stabilises the knee, allowing it to rotate.

An MCL injury most commonly occurs from a direct blow to the outside of the knee, resulting in a tear of the MCL and possibly the ACL or other ligaments. It usually takes around six weeks for an MCL injury to heal. In most cases, the MCL responds to non-surgical treatment. However, in rare cases, surgery may be required.

Meniscus injuries

The meniscus is articular cartilage in the knee joint that functions as shock absorber for the knee. Meniscus injuries can be caused by a direct blow to the knee (trauma), or from wear and tear. Degeneration causes progressive loss of the cartilage tissue which can lead to osteoarthritis in the bone.

Meniscus injuries are marked by non-specific pain and inflammation in the knee, stiffness and diminished range of motion. Injury to the articular cartilage in the knee can be treated through arthroscopic surgery. For more progressive or grave injuries, transplant of cartilage from another region of the knee could be needed. In certain cases where articular cartilage has totally disintegrated, a total knee replacement (TKR) may be necessary. Pain or range-of-motion problems can often be addressed through physical therapy, supportive devices and anti-inflammatory medication.

Articular cartilage damage

It is damage to the smooth cartilage covering the ends of bones, allowing frictionless movement. It can occur with ACL or meniscus injuries or direct trauma. Symptoms include pain, stiffness, swelling and sometimes catching. Treatment protocols are usually focused on preservation and can range from physical therapy to advanced cartilage repair which entails a longer recovery period.