KNEE CONDITIONS

Knee Anatomy:

There are four bones in the knee, the tibia (shin bone), fibula (outside of the lower leg), femur (upper leg bone) and patella (knee cap). They are held together by four main ligaments, your anterior and posterior cruciate ligaments (ACL,PCL), and your lateral and medial collateral ligaments (MCL, LCL).

A meniscus is a cresent shaped, cartilagagenous struture of the inner knee, that lies in between the tibia and femur. It is made up of two parts, the medial (inside) and lateral (outside) meniscus. The menesci serve to absorb shock and to stabilize the knee.

Articular cartilage is found in all joints of the body. It covers the ends of "articulating" bones, allowing then to glide smoothly across one another. In the case of the knee, it is found on the end of the tibia and femur and on the back of the knee cap.

Bursa are fluid filled sacs located around joints in order to reduce friction between the tissues and bone. There are four major bursea of the knee: the prepatellar (most commonly injured), suprapetellar, superficial infrapatellar, and deep infrapatellar.

Tendons are abundant when talking about the knee. The patellar tendon is a combination of all four of your quadriceps muscles. It surrounds the back of the knee cap and attaches into the front of the shin bone (just below the knee cap). The adductor group serve to bring the knee towards the body and attach at various points on the inner knee. The idiotically band is a major part of the outside of the knee. It starts at the hip and ends on the side of the tibia. Your idiotically band is actually made up of fascia and therefore cannot contract. It does however work closely with your tensor fascia Plata muscle. Your hamstrings, which start from the bone in your bum and end on the medial and lateral sides of your tibia.

The iliotibial band is a major part of the outside of the knee. It starts at the hip and ends on the side of the tibia. Your iliotibial band is actually made up of fascia and therefore cannot contract. It does however work closely with your tensor fascia lata muscle. When the TFL contracts, it pulls on the IT band, which in turn moves the knee.

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LIGAMENT DAMAGE

ACL Injury:

Your ACL is a ligament that runs from the the front of the tibia to the back of the femur. It protects against excessive forward pressure of the tibia and rotation of the knee. It is most commonly injured as a result of a twisting motion or a hard blow to the side or back of the knee. The ligament can either receive a small tear or completely rupture. Recovery time depends on the severity of the tear.

PCL Injury:

Your PCL is also a ligament in the knee but it runs from the back of the tibia to the front of the femur. It protects against excessive backward pressure of the tibia. It is most commonly injured by a hard blow to the front of the shin bone. The ligament can either receive a small tear or completely rupture. Recovery time depends on the severity of the tear.

MCL Injury:

A ligament located on the inside of the knee, the most commonly injured ligament of the knee. It protects the knee against excessive valgus force (pressure placed on the outer side of the knee, causing the knee to bend inwards). It is ost commonly injured by a hard blow to the outer side of the knee. The ligament can either receive a small tear or completely rupture. Recovery time depends on the severity of the tear.

LCL Injury:

A ligament located on the outside of the knee. It protects the knee against excessive varus force (pressure placed on the inside of the knee, causing the knee to bend outwards). It is most commonly injured by a hard blow to the inside of the knee. The ligament can either receive a small tear or a complete rupture. Recovery time depends on the severity of the tear.

Meniscal Tear:

Injuries to the meniscus are common and typically as a result of twisting the knee while weight bearing. A tear to one or more of the ligaments in the knee can result in a torn meniscus. It is important to remember that it can also degenerate with age, making it more susceptible to injury. The medial aspect of the meniscus is most often injured.

Symptoms include pain on the medial and lateral aspects of the knee when bending or twisting. A piece of the meniscus may rip off and create problems such as locking, clicking or catching within the joint.

Patellofemoral Pain:

The word patellofemoral refers to the area made up of the patella (patello) and the femur (femoral). Pain occurs in this area when the knee cap is compressed against the groove of the femur (femoral groove). Increased or repetitive bending of the knee will in turn increase the pain. Activities such as climbing or descending stairs after a period of rest often aggravate this problem.

Causes of this condition may include poor patellar tracking, flat feet, weak thigh muscles or ligaments, a previous injury to the area and/or overuse.

Iliotibial Band Syndrome:

Iliotibial band syndrome is a condition of the band of fascia located at the side of the hip, running down into the side of the knee. Your IT band connects to many muscles, a major one being the tensor fascia lata (TFL), which literally means to tense your lateral fascia (your IT band). When the fascia is tensed, it pulls the leg away from the body. The IT band also serves to stabilize the outside of the knee.

A bursa lies underneath the IT band to prevent friction between the IT band and the femur. Repetitive flexion and extension of the knee causes the IT band to slip back and forth across the condyle of the femur (bony projection on the outside of the knee), this motion can irritate the bursa, potentially making it inflamed and irritated.Another problem seen with the IT band is when it adheres to one of the quadriceps muscles called vastus lateralis. It is important to address both issues when treating a patient for IT band syndrome.

Prepatellar Bursitis:

The prepatellar bursa is a thin, fluid filled sac, used to reduce friction between the patella and the overlying skin. Of thenumerous bursa surrounding the knee, the prepatellar bursa is the most likely to be inflamed. A blow to the front of the knee is most likely to be the cause.

Most people notice that the front of the knee is painful during movement and painful to the touch. There may also be swelling and heat in the area. Chronic cases may have scar tissue build up on the walls of the bursa.

Osgood-Schlatter's Knee Pain:

This disease is often seen in young people who are still in the growing stages. It is usually as a result of over activity of the legs. Repetitive flexion and extension of the knee will place stress on the growing bones, creating pain where the patellar tendon inserts (about 3 fingers below the kneecap). The pain may also radiate to the outside of the knee and into the knee cap. Jumping, starting, stopping and running can aggravate this problem.

Osteoarthritis:

Osteoarthritis involves the breakdown of the cartilage in a joint. It is one of the most common forms of arthritis and is very often seen in the knees. When the cartilage used to help bones slide easily against one another deteriorates, the joint may become weak, painful and stiff.

OA typically starts gradually as a casual pain or stiffness of the joint. It may then progress, making it difficult to climb and descend stairs and perform daily activities. Rarely will you see inflammation (pain, swelling, redness) as you might in other inflammatory or erosive osteoarthritis'. Some common symptoms of OA are joint soreness following overuse activities, morning stiffness lasting around 30 minutes, pain that is worse at the end of the day, knee catching or locking, and weakened thigh muscles.

Middle aged people are mostly affected, women more so than men. This is thought to be because of the broadness of women's hips, creating more torsion on the knees. Age does increase the risk for developing OA.

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Patellar Tendonitis/Tendonosis:

The patellar tendon may receive micro-tears in the tissue that can a) cause inflammation in the area which would be referred to as a tendonitis or b) heal improperly, but not cause an inflammatory effect, which we would then call a tendonosis. Treatment for these conditions are profoundly different in that all inflammatory conditions are treated with non steroidal anti-inflammatory drugs (NSAID's), an approach you cannot take to a non inflammatory condition.

Patellar tendonitis occurs in people who are placing too much stress on the patellar tendon and quadriceps muscles. Pain will be felt at the bottom of the knee cap and can be accompanied by swelling and sensitivity.

Chondromalacia:

Articular cartilage covers the back of the knee cap, and the ends of the tibia a femur. Chondromalacia occurs when the cartilage on the underside of the knee cap becomes irritated. The knee cap tends to rub against the knee joint, causing pain in the front of the knee. It most often occurs in young, athletic individuals, women are more common than men.

Baker's Cyst:

Also known as a popliteal cyst, a baker's cyst is most often a symptom of another underlying problem. Fluid builds up inthe back of the knee joint, one cause is when the joint capsule herniates into the back of the knee. Conditions like arthritis and tissue tears can cause swelling of the knee, often leading to a baker's cysts. You must treat the primary problem if you wish to treat the cyst.

Synovial Plica Syndrome:

This conditions occurs when a piece of fetal tissue (plica) remains in the knee. During development, the plica (membranes) separate the knee into it's compartments and become smaller during the second trimester. As we age, they are referred to as synovial folds. In some people, the plica is more prominent, leaving it vulnerable to irritation and inflammation. The medial shelf plica is common in these cases, usually as a result of other overuse injuries.

Gout:

Gout is typically seen in the big toe of males over the age of 40. With 75 years being the peak age. Although it is not very common in the knee, it can happen. It causes sudden, severe pain of the joint, accompanied by swelling and redness.

The kidneys produce a substance called uric acid. It helps our body to excrete waste products. Gout occurs when there is an impairment of the transportation of uric acid. There is an abundance of uric acid in the blood stream, which travels into the joints and creates crystal deposits.

Genetics play a role in this disease as well as obesity, sudden weight gain, abnormal kidney function, excessive alcohol consumption, and some cancers. The relationship between uric acid levels in the blood stream and gout is unclear. People with high levels of uric acid in their blood do not always have gout and visa versa.

Knee Pathology Facts

Almost 5 million people visit offices of orthopaedic surgeons each year because of knee problems. More than 3 million of the visits are injury-related; the remaining are due to arthritis and other disorders.

Another 1.4 million people go to a hospital emergency room for knee problems; 80 percent of the visits are due to injuries.

In 1994, 7,000 hospital visits were recorded for patients with a torn quadriceps tendon; 39.8 percent of the patients were under 18 years old; 24.7 percent, 18-44 years old; 25.7 percent were 45-64 years old; 9.8 percent were 65 or older.

In 1994, there were 50,000 hospital admissions for repair of the anterior cruciate ligament or posterior cruciate ligament in the knee.

More artificial joint replacements are performed on the knee than any other joint.

9.2 days was the mean length of stay in hospitals for injuries to knee and lower leg in England 2002-03 (Hospital Episode Statistics, Department of Health, England, 2002-03)

Knee Procedures

* Repair of knee, repair of ligaments, knee replacements and revisions of knee replacements

1994 Total Knee Replacements

Reference: http://www.arthroscopy.com/sp13008.htm

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