The knee joint is fragile and can be vulnerable to damage. There are several common knee injuries; these are outlined below:
Dislocation: this can occur when the kneecap becomes dislodged or when the bottom of the femur becomes dislodged from the shin bone. Usually kneecaps can be pushed back in fairly easily; this may be very painful but will ease fairly quickly. Kneecap dislocations usually occur as a result of a quick or sudden movement. Knee joint dislocations are more serious and are often caused by landing in an awkward position or high-speed impacts such as a car accident or sports injury. Knee joint dislocations often causes extensive damage to the ligaments and cartilage surrounding the knee; these will commonly have to be repaired surgically; recovery can take several weeks and should be taken slowly in order to let the joint heel and prevent further damage.
Ligament sprains: ligaments support the knee joint and allow flexibility and movement. Ligament sprains are fairly common in sport and are often caused by over extending the knee joint during actions which require reaching for something or moving quickly; they are also common in contact sports. Mild sprains usually heal quickly while more serious sprains can take a while to recover. These injuries are usually very painful immediately after the sprain has occurred.
Cartilage tears: these occur in either the outside (lateral meniscus) or the inner (medial meniscus) cartilage. Cartilage supports the knee during movements but can often be damaged by quick, sudden or twisting movements. Tears are common in sports which involve having quick feet such as football and tennis. The knee will often swell and be very painful if cartilage tears. Minor tears heal over a period of about 6 weeks; the patient should rest and refrain from moving the joint as much as possible during the healing process; a combination of ice and anti-inflammatory medication will usually aid recovery. Serious tears can be debilitating and may take a long time to recover; surgery may also be required, although it may be advisable or possible in some cases; this is usually carried out by means of an arthroscopy.
Recovering from a knee joint injury
Recovery depends on the injury; however almost all knee joint injuries will require a lengthy period of rest. Some may require surgery which will usually prolong the recovery process but will ensure optimum results in most cases. Exercise should be undertaken gradually once the joint has healed. Physiotherapy may also be useful in order to strengthen the joint and improve the range of movement. Ice and anti-inflammatory medication will help to reduce swelling.
Source : http://www.nsmi.org.uk