All About Your KneeArunesh Chand Mankotia

15 May 2013

Knee Pain Overview

Knee pain is the most common musculoskeletal complaint that brings people to their doctor. With today's increasingly active society, the number of knee problems is increasing.

Knee pain has a wide variety of specific causes and treatments.

Anatomy of the KneeThe knee joint's main function is to bend, straighten, and

bear the weight of the body along with the ankles and hips. The knee, more than just a simple hinged joint,

however, also twists and rotates. In order to perform all of these actions and to support the entire body while doing so, the knee relies on a number of structures including

bones, ligaments, tendons, and cartilage.

BonesThe knee joint involves 4 bones.

The thighbone or femur comprises the top portion of the joint.

One of the bones in the lower leg (or calf area), the tibia, provides the bottom weight-bearing portion of the joint.

The kneecap or patella rides along the front of the femur.

The remaining bone in the calf, the fibula, is not involved in the weight-bearing portion of the knee joint. It only provides ligament

attachments for stability.

LigamentsLigaments are dense fibrous bands that connect

bones to each other.The knee includes 4 important ligaments, all of

which connect the femur to the tibia:The anterior cruciate ligament (ACL) and 

posterior cruciate ligament (PCL) provide front and back (anterior and posterior) and

rotational stability to the knee.The medial collateral ligament (MCL) and lateral

collateral ligament (LCL) located along the inner (medial) and outer (lateral) sides of the knee provide medial and lateral stability to

the knee.

TendonsTendons are fibrous bands similar to ligaments.Instead of connecting bones to other bones as

ligaments do, tendons connect muscles to bones.The 2 important tendons in the knee are (1) the

quadriceps tendon connecting the quadriceps muscle, which lies on the front of the thigh, to

the patella and (2) the patellar tendon connecting the patella to the tibia (technically

this is a ligament because it connects 2 bones).The quadriceps and patellar tendons are

sometimes called the extensor mechanism, and together with the quadriceps muscle they

facilitate leg extension (straightening).

CartilageCartilaginous structures called menisci (one is a meniscus) line the top of the tibia and lie between the tibia and the 2

knuckles at the bottom of the femur (called the femoral condyles).

The menisci's primary job is to provide cushioning for the knee joint.

BursaeBursae (one is a bursa) are fluid-filled sacs that help to

cushion the knee. The knee contains 3 important groups of bursae:

The prepatellar bursae lie in front of the patella.The anserine bursae is located on the inner side of the knee

about 2 inches below the joint.The infrapatellar bursae are located underneath the patella.

 

Home Care for Knee PainInflammation is the body?s physiologic response to an injury. In treating many types of knee pain, a common

goal is to break the inflammatory cycle. The inflammatory cycle starts with an injury. After an

injury, substances that cause inflammation invade the knee, which causes further injury, which leads to

further inflammation, and so on. This cycle of inflammation leads to continued or progressive knee

pain. The cycle can be broken by controlling the substances that cause inflammation, and by limiting

further injury to tissue.Some common home care techniques for knee pain that

control inflammation and help to break the inflammatory cycle are protection, rest, ice, compression, and elevation. This regimen is summarized by the memory device PRICE.

PROTECT the knee from further trauma.This can be done with knee padding or

splinting.A pad over the kneecap, for example, helps to

control the symptoms of some knee injuries (an example is a form of bursitis sometimes

called housemaid's knee) by preventing further repetitive injury to the prepatellar

bursae.REST the knee.

Rest reduces the repetitive strain placed on the knee by activity.

Rest both gives the knee time to heal and helps to prevent further injury.

ICE the knee.Icing the knee reduces swelling and can be used

for both acute and chronic knee injuries.Most authorities recommend icing the knee 2 to 3

times a day for 20-30 minutes each time.Use an ice bag or a bag of frozen vegetables

placed on the knee.COMPRESS the knee with a knee brace or wrap.

Compression helps accomplish two goals:First, compression is another way to reduce

swelling.Second, in some knee injuries, compression can be used to keep the patella aligned and to keep

joint mechanics intact.

ELEVATE the knee.Elevation also helps reduce swelling.

Elevation works with gravity to help fluid that would otherwise accumulate in the knee flow back to the central circulation.

Prop your leg up when you are sitting, or use a recliner, which naturally elevates the legs. Elevation works best when the knee

-- or any other injured body part -- is higher than the level of the heart.

When to Go to the Hospital for Knee PainIf you cannot put weight on your knee, you should consider going to the ER to be evaluated by a doctor because of the

possibility of a fracture.Many fractures may require immobilization in a specific

position or surgery.Putting off seeing a doctor may hinder healing.

Other signs and symptoms that demand emergency evaluation:

Fever (which may indicate infection)Unbearable pain

DrainageLarge wounds

Puncture woundsSwelling, if you are on a blood thinner (warfarin or Coumadin

) or have a bleeding disorder (such as hemophilia)

The doctor will also want to know a bit about you.

Do you have any major medical problems?How active is your lifestyle?

What are the names of the medications you are taking?

The doctor will want to know about any related symptoms.

Do you still have normal sensation in your foot and lower leg?

Have you been having fevers?

Physical examThe doctor will likely have you disrobe to completely expose the

knee. If possible, wear shorts to your appointment.The doctor will then inspect the knee and press around the knee

to see exactly where it is tender.In addition, the doctor may perform a number of maneuvers to 

stress the ligaments, tendons, and menisci of the knee and evaluate the integrity of each of these.X-rays, CT scans, and other tests

Depending on your particular history and exam, the doctor may suggest X-rays of the knee. X-rays show fractures (broken bones) and dislocations of bones in the knee as well as 

arthritis and abnormally large or small joint spaces.Rarely, the doctor may order a CT scan (a 3-dimensional X-ray)

of the knee to precisely define a fracture or deformity.Both X-rays and CT scans are excellent for diagnosing fractures.

They both are also poor, however, at evaluating soft tissue structures of the knee such as ligaments, tendons, and the

menisci.

MRIMagnetic resonance imaging (MRI) uses large magnets to create a

3-dimensional image of the knee.In contrast to CT scans, MRIs do not image bones and fractures as

well.Also in contrast to CT scans, MRIs are excellent for evaluating

ligaments and tendons for injuries.Fluid removal

The knee and all bursae of the knee are filled with fluid.If your symptoms suggest infection or crystalline arthritis, such as 

gout, your physician may remove fluid, with a needle, from the knee.

This fluid will then be analyzed to better clarify the diagnosis.Crystals, which suggest crystalline arthritis, often can be seen under the microscope. Infection may also be detected under a

microscope by finding bacteria and pus in the fluid.Blood tests: The doctor may also elect to perform certain blood

tests to evaluate for signs of infection or diseases such as rheumatoid arthritis, lupus, and diabetes

ArthroscopyThe orthopedic surgeon may elect to perform

arthroscopy if you have chronic knee pain.This is a surgical procedure where the doctor will

place a fiber optic telescope within the knee joint. The arthroscope is attached to a camera

that relays real-time images to a video monitor.By doing so, the surgeon may be able to see

small particles in the knee or to look more closely at damaged menisci or cartilage.

The doctor may also be able to repair damage by shaving down torn cartilage or removing particles from the knee while looking at the

inside of your knee on a video monitor.

Types of Knee PainThe nerves that provide sensation to the knee come

from the lower back and also provide hip, leg, and ankle sensation. Pain from a deeper injury (called

referred pain) can be passed along the nerve to be felt on the surface. Knee pain, therefore, can arise from the knee itself or be referred from conditions of the hip, ankle, or lower back. All of the following

sources of knee pain arise from the knee joint itself.

In general, knee pain is either immediate (acute) or long-term (chronic). Acute knee pains can be

caused by an acute injury or infection. Chronic knee pain is often from injuries or inflammation

(such as arthritis) but can also be caused by infection.

Acute Knee PainSprained and Torn Cruciate Ligaments

Description: An anterior cruciate ligament (ACL) injury is a common sports injury generally caused by a hard stop or a violent twisting of the knee. The posterior cruciate ligament

(PCL) is stronger than the ACL and much less commonly torn. The PCL requires strong forces, such as those produced when the dashboard strikes the knee in a car accident, to tear. Due

to these severe forces, PCL injury is often associated with other ligamentand bone injuries.

Symptoms: If you tear your ACL, you may hear a pop. You will also notice your knee give way or become unstable and feel

pain that is bad enough that you might feel like vomiting. This will, almost always, be followed by marked knee swelling over the next couple of hours because the ACL bleeds briskly

when torn.Treatment: Surgical repair is recommended for high-level

athletes who demand optimal outcomes. Conservative treatment and knee braces may prove sufficient for those

who do not demand quite so much from their knees.

Tendon RupturesDescription: Both the quadriceps and patellar tendons may rupture partially or completely. A quadriceps tendon

rupture typically occurs in recreational athletes older than 40 years (this is the injury former President Clinton

suffered while jogging), and a patellar tendon rupture typically occurs in younger people who have had

previous tendonitis or steroid injections to the knee.Symptoms: Rupture of either the quadriceps or patellar

tendon causes pain (especially when trying to kick or extend the knee). Those people with complete ruptures are unable to extend the knee. The patella is also often

out of place either upward (with patellar tendon rupture) or downward (with quadriceps tendon rupture).

Treatment: Tendon ruptures should be evaluated urgently. Tendon ruptures generally require surgical repair. A partial rupture may be treated with splinting alone.

Meniscal InjuriesDescription: Injuries to the meniscus are typically

traumatic injuries but can also be due to overuse. Often, a piece of the meniscus will tear off and

float in the knee joint.Symptoms: Meniscal injuries may cause the knee

to lock in a particular position, or either click or grind through its range of motion. Meniscal injuries

may also cause the knee to give way. Swelling typically accompanies these symptoms although

the swelling is much less severe than with an ACL injury.

Treatment: Meniscal injuries often require arthroscopic surgical repair. A locking knee or a

knee that "gives" should be evaluated for arthroscopic repair.

Meniscal InjuriesDescription: Injuries to the meniscus are typically

traumatic injuries but can also be due to overuse. Often, a piece of the meniscus will tear off and

float in the knee joint.Symptoms: Meniscal injuries may cause the knee

to lock in a particular position, or either click or grind through its range of motion. Meniscal injuries

may also cause the knee to give way. Swelling typically accompanies these symptoms although

the swelling is much less severe than with an ACL injury.

Treatment: Meniscal injuries often require arthroscopic surgical repair. A locking knee or a

knee that "gives" should be evaluated for arthroscopic repair.

Knee DislocationDescription: Knee dislocation is a true limb-threatening

emergency. This is also a rare injury. Dislocation of the knee is caused by a particularly powerful blow to the

knee. The lower leg becomes completely displaced with relation to the upper leg. This displacement stretches

and frequently tears not only the ligaments of the knee but also arteries and nerves. Untreated arterial injuries leave the lower leg without a blood supply. If circulation

is not restored, amputation may be required. Nerve injuries, on the other hand, may leave the lower leg

viable but without strength or sensation.Symptoms: Knee dislocations are severely painful and

produce an obvious deformity of the knee. Many dislocations are reduced -- or put back into alignment -- on their own. As this occurs, many will report feeling a

dull clunk.

Treatment: If the knee dislocation has not been put back into place on its own, the doctor will immediately reduce the dislocation. Medical treatment, however, does not stop here. Whether a dislocation reduces by itself or is put back into place in the hospital, it requires further evaluation and care.

After reduction, people with these injuries are observed in the hospital where they usually do a number of tests to ensure that no arterial or nerve

injury has occurred. If such an injury is found, it must be repaired immediately in the operating room.Dislocated Kneecap (patella)

Description: A common injury caused by direct trauma or forceful straightening of the leg, such as an injury that happens when serving in volleyball or tennis. Kneecap dislocation is more common in women, the

obese, knock-kneed people, and in those with high-riding kneecaps.Symptoms: If you have this injury, you will notice the patella being out of

place and may have difficulty flexing or extending your knee.Treatment: The doctor will move the patella back into place (reduce the

dislocation). Even if the patella goes back into place by itself, however, it needs to be X-rayed for a fracture. After reducing the patella and ensuring the absence of a fracture, the doctors will treat these injuries by splinting the knee for 3 weeks to allow the soft tissues around the patella to heal

followed by strengthening exercises to keep the patella in line. This injury often causes damage to the cartilage on the back of the patella.

Knee Pain PreventionKnee pain has a host of causes. Many types of pain are difficult to prevent, but

you can do some general things to reduce the likelihood of sustaining a knee injury.

Stay SlimStaying slim reduces the forces placed on the

knee during both athletics and everyday walking and may, according to some

medical research, reduce osteoarthritis.Keeping your weight down may also reduce the number of ligament and tendon injuries

for similar reasons.

Keep Limber, Keep FitMany knee problems are caused by tight or

imbalanced musculature. Stretching and strengthening, therefore, also help to prevent

knee pain.Stretching keeps your knee from being too

tight and aids in preventing both patellofemoral syndrome and iliotibial band

syndrome.Strengthening exercises particularly of the

quadriceps (straight leg raises and leg extensions are two excellent exercises, but

please see a book on exercise and training for more) can help prevent knee injury.

Exercise WiselyIf you have chronic knee pain, consider swimming or

water exercises.In water, the force of buoyancy supports some of our

weight so our knees do not have to.If you don't have access to a pool or do not enjoy water activities, at least try to limit hard pounding

and twisting activities such as basketball, tennis, or jogging.

You may find that your aching knees will act up if you play basketball or tennis every day but will not if you limit your pounding sports to twice a week.

Whatever you do, respect and listen to your body. If it hurts, change what you are doing.

If you are fatigued, consider stopping -- many injuries occur when people are tired.

Protect the KneeWearing proper protection for the activity at

hand can help avoid knee injuries.When playing volleyball or when laying

carpet, protecting your knees may include kneepads.

When driving, knee protection may include wearing a seatbelt to avoid the knee-versus-dashboard injuries as well as injuries to other parts of your body.

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