The document provides an overview of the anatomy of the knee, including the bones, ligaments, tendons, cartilage, and bursae. It then discusses common causes of acute and chronic knee pain such as injuries to the ACL, meniscus, and tendons. It outlines treatments for various conditions including PRICE therapy, surgery, and rehabilitation. The document emphasizes the importance of maintaining a healthy weight and lifestyle to prevent knee problems through exercises, stretching, and limiting high-impact activities.

1. All About Your Knee
Arunesh Chand Mankotia
15 May 2013

2. 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 Knee
The 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.

3. Bones
The 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.

4. Ligaments
Ligaments 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.

5. Tendons
Tendons 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).

6. Cartilage
Cartilaginous 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.
Bursae
Bursae (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.

7. Home Care for Knee Pain
Inflammation 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.

8. 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.

9. 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.

10. 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.

11. When to Go to the Hospital for Knee Pain
If 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
Drainage
Large wounds
Puncture wounds
Swelling, if you are on a blood thinner
(warfarin or Coumadin) or have a bleeding disorder
(such as hemophilia)

12. 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?

13. Physical exam
The 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.

14. MRI
Magnetic 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

15. Arthroscopy
The 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.

16. Types of Knee Pain
The 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.

17. Acute Knee Pain
Sprained 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.

18. Tendon Ruptures
Description: 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.

19. Meniscal Injuries
Description: 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.

20. Meniscal Injuries
Description: 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.

21. Knee Dislocation
Description: 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.

22. 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, theobese, 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.

23. Knee Pain Prevention
Knee 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 Slim
Staying 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.

24. Keep Limber, Keep Fit
Many 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.

25. Exercise Wisely
If 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.

26. Protect the Knee
Wearing 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.

27. THANK YOU