Knee

toc

The knee is a joint of the lower body. It is the contact of two or more bones at a certain location, which allow movement and support of the body.

= = =Anatomy= The knee appears to most as a simple [|hinge joint], yet it is one of the most complicated joints in the human body. It is a lower body joint, and it holds nearly all of the body's weight! It transfers and accepts the weight of the body between the femur, tibia, fibula and patella, all which are bones of the leg, as shown below.


 * Did you know?** //Did you know that when you are born you do not have a kneecap? The "kneecap" of babies are made up of cartilage. The kneecap then forms at 3 for girls, 5 for boys.//

__//**There are 5 important bones of the knee.**//__ 1. __Femur__- also known as the thigh bone, it is the largest and strongest bone of the body and provides attachment between many of the muscles of the knee. 2. __Condocyle__- this bone makes up rounded part of the femur, which allows the femur to move easily over shinbone 3.Tibia- this bone is the second largest bone in the body and assists in the rotations of the knee. It can hold a lot of weight and also acts as a shock absorber. 4.__Fibula__- this bone can not bear much weight, but it provides flexabity and attachment for tendons. 5.__Patella__-also known as the knee cap, this bone acts as support for the quads by holding the quad tendons off lower end of femur. The fibula and tibula, meet to form a hinge joint. The patella (knee cap) protects this joint.

__//**Movement of the knee**//__ The name of the type of joint at the knee is a hinge joint. The hinge joint allows for the bending, or //flexion,// and extension of the knee. The ligaments and muscles surrounding the joint protect the knee and prevent it from moving or bending beyond its proposed range of motion.

//__**There are 2 types of cartilage of the knee**__// 1.__Menisci__-this is the thin C-shaped layer of the fibrocartilage in the knee which acts as a shock absorber. Because it has no blood supply, when it is damaged it is unable to heal normally. There are two types of this cartilage in the knee: the lateral and medial menisci. 2.__Articular Cartilage__- smooth and very slick material which covers the thighbone, shinbone, and the underside of the kneecap which allows bones to move smoothly

1.Superior medial genicular artery 2. Superior lateral genicular artery 3. Inferior medial genicular artery 4. Inferior lateral genicular artery 5. Descending genicular artery 6. Recurrent branch of anterior tibial artery 7. Medial genicular arteries penetrate the knee joint.
 * //__There are 7 Blood Supplies to the knee__//.**

//Did you know?// Did you know there is a phobia of the knees? It is called genuphobia.

1. __ACL (anterios cruciate ligament)__- major stabalizing ligament of knee, located in center of knee and runs through femur (thigh bone) and tibia (shin bone). 2. __PCL(posterior cruciate ligament)__- knee's basic stabalizer, prevents femur from moving too far forward over tibia, twice as strong as ACL 3. Collateral ligament- prevents hyperextension, adduction, and abduction 4. __Patellar ligament(anterior ligament__)-strong, flat ligament which is the central portion of the quad tendon 5. __Medial collateral ligament (MCL__)-one of four major ligaments of the knee, resists force by pushing knee to body 6. __Lateral collateral ligament__-one of four major ligaments of knee, resists force by pushing knee away from body 7. __Oblique popliteal ligament__- flat, fibrous band which is seperated by blood vessels and nerves 8. __Arcuate popliteal Ligament__-connects from head of fibula to articular capsule
 * //__There are 8 important ligaments in the knee__//**

=Injury= = = Injuries to the knee are common due to sports and old age. Usually a knee injury occurs from force on the knee or violent twisting motions. The most common injury to a knee is arthritis, which is caused by the wearing away of cartilage in the knee, and as a result inflames the joint. Affects of arthritis to the knee include pain and swelling. Total knee replacement is a surgical procedure where an arthritic knee joint is resurfaced with metal or plastic replacements called a protheses. Injury to tendons or ligaments in the leg are also a general cause of knee pain. The Anterior Cruciate Ligament, or ACL, is a frequent site for injury, usually form a sports-related issue or a simple twisting motion. When this ligament is torn, a patient may undergo ACL reconstruction. Image Courtesy of Flickr user cherieladie.

//**What happens during surgery?**// [|Click here to do a Virtual Surgery of the Knee, and also see pictures of a real knee surgery!]
 * When performing surgery, an anesthesiologist puts the patient into a sleep, but it is mandatory to make sure the vital signs are okay before surgery.
 * A knee must be worn down and lacking cartilage to perform surgery.
 * Anesthesia is used so that the patient does not feel pain during the surgery.
 * Betadine, which is used to clean wounds, sterilizes the leg; it is done twice then covered in drapes to keep it sterile.
 * Lines are drawn to help line up skin when closing the leg up after surgery.
 * A scalpel is used to cut the skin open. A scalpel is an extremely sharp knife used for surgery.
 * A bovie is used to cauterize, or stop the bleeding of veins. A bovie is a medical instrument that stops bleeding through the application of heat to the area.
 * Rongeur is used to reshape the bone. A rongeur is a sharp-edged medical tool used to gouge out bone.
 * A jig is placed to help guide and make sure all cuts made to the bone are precise and needed.
 * The bone is cut and a new jig is added to cut the femur and make sure the knee is perfectly aligned.
 * The tibia and fibula are then cut.
 * The femoral component is placed.
 * Then the metal tray component is added.
 * The plastic spacer is then placed.
 * After that, the patellar component is placed.
 * The surgeon checks for gaps to prevent the knee from bending sideways.
 * Then, they remove the trial components and apply a cement component and insert permanent components.
 * This new knee has to withstand 5x the weight.

= = =Rehabilitation of the Knee=

Knee replacement surgery is very complex, and the physical knee rehabilitation is extremely crucial. For the healing of the knee to be successful, the person must take ownership and follow through with the 4 phases of the rehab process.

//Phase 1-//
After surgery the first goal is to greaten the knee's range of motion. Also, swelling, pain, joint malfunctions, and inflammation must be taken care of. Inflammation //__will__// occur in the knee joint after surgery. Managing the inflammation can be done through controlling the pain and regulating the motion of the joint. Also, the knee joing will need protection and a brace will be assigned.

courtesy of [|jointhealing.com]

//Phase 2-//
The goal of this phase is to re-establish full mobility. To do this, weight bearing exercises will be introduced according to strength and level of healing the knee is at. Endurance exercises will also be added to make sure the person maintains a healthy fitness level. courtesy of [|chester knee clinic]

//Phase 3-//
The person will then continue with advanced resistive exercises and functional activities. [|Plyometrics], balance, and agility exercises are increased while the protection and limitations of the knee are decreased.

//Phase 4-//
For athletes: the ability to return to play in their sport is based upon the performance in a series of tests including functional tests, isokinetik tests, and their psychological state of mind.

1. [|http://en.wikipedia.org/wiki/Knee#Injury.] 2. [|http://www.edheads.org/activities/knee/index.htm.] 3. [|http://www.nlm.nih.gov/medlineplus/kneeinjuriesanddisorders.html.]
 * Sources and sites with further information on the knee include:**

Website by: Angeline, Samantha and Ashley