Your knee joint is one of the most intricate joints in your body. It is also, according to Arthroscopy.com, a joint that is highly susceptible to injury. This is largely because in addition to its ability to bend, or flex and extend, it also has a slight capacity to rotate. Important aspects of knee stability are ligaments that work to hold your knee together. If ligaments sustain damage, as can happen during knee hyperextension, your knee becomes unstable and may not be able to support your weight.
Cause
Knee hyperextension occurs when your knee bends backward further than its normal position. Common causes of knee hyperextension injuries include car accidents, falls and sports that place extreme stress on knee joints, such as gymnastics, basketball, volleyball or football.
Effect
The straighter and tenser your knee joint is when it receives a blow, the greater the damage will be. A worst-case scenario involves a car accident, which can result in knee dislocation as well as several torn or detached knee ligaments. Knee hyperextension injuries that occur because of sports are, according to MayoClinic.com, usually less severe and often involve only the anterior cruciate ligament, or ACL. Symptoms can range from bruising and swelling to knee instability, limited range of motion and varying degrees of pain when you attempt to straighten your leg.
Surgical Repair
If your knee hyperextension injury is severe enough to require surgery, you doctor will most often use a method the American Academy of Orthopaedic Surgeons identifies as arthroscopic surgery. Arthroscopic surgery is less invasive outpatient surgery that uses small incisions and cameras. Repairs generally consist of removing the damaged ligament or ligaments and replacing them with tendons. If, for example you tear your ACL, your doctor will make repairs by replacing the torn ligament with hamstring tendons.
Treatment
If your knee hyperextension injury is less severe, or you are recovering from surgery, treatment typically consists of rest, physical therapy and exercise you do at home to strengthen knee muscles. Recovery generally begins with a period of rest. Once swelling and pain decrease and you regain some range of motion in your knee, light strength training exercises can begin. The muscle groups on which you focus will depend on the injured ligament or ligaments. For example, according to AthleticAdvisor.com, if you injure your posterior cruciate ligament, or PCL, strength training will focus on quadriceps, or thigh muscles. Strength training will become more intense as healing progresses and include both agility and endurance training. Total recovery time for a less severe injury depends largely on your participation in physical therapy and rehabilitation exercises. If you are recovering from surgery, AthleticAdvisor.com says you can expect recovery to take four to six months.
