Topic Overview
What is patellar tracking disorder?
Patellar
tracking disorder occurs when the kneecap (patella) shifts out of place as the
leg bends or straightens. In most cases, the kneecap shifts too far toward the
outside of the leg, although in a few people it shifts toward the
inside.
Your knee joint is a complex hinge that joins the lower
leg bones (tibia and fibula) with the thighbone (femur). The kneecap is held in
place in the front of the knee joint by
tendons on the top and bottom and by
ligaments on the sides. A layer of
cartilage lines the underside of the kneecap, helping
it glide along the groove at the end of your thighbone.
The
kneecap can shift or rotate off track if the groove is too shallow or if the
cartilage is damaged. Ligaments, tendons, or muscles that are too loose or too
tight may also lead to a misaligned kneecap.
See a picture of the
knee joint.
What causes patellar tracking disorder?
A
patellar tracking disorder is usually caused by
several problems combined. The shape of the patella; too tight or too loose
muscles and tendons in the leg, foot, or hip areas; damage to cartilage; and overuse may lead to
patellar tracking disorder. See a picture of the
muscles and tendons related to patellar tracking disorder.
Also, a
severe blow to the inside of a healthy knee can knock a kneecap out of
alignment or, in extreme cases, dislocate it. Symptoms of a dislocated kneecap
include the knee looking misshapen like a bone is out of place, not being able
to bend or straighten the knee, knee swelling, and severe pain.
Sometimes patellar tracking problems run in the family. If you have a
family member with knee pain, you may want to take preventive measures, such as
strengthening your thigh muscles.
What are the symptoms?
If your kneecap is out of
alignment, you may have discomfort or pain, especially when you go down stairs,
sit for a long time, stand up from sitting, or squat. This kind of pain, also
known as patellofemoral pain, may be caused by patellar tracking
disorder.
You also may feel a popping, grinding, slipping, or
catching of the kneecap when you bend or straighten your leg. Or you may feel
that your knee is buckling or giving way, as though the knee suddenly cannot
support your body weight.
How is patellar tracking disorder diagnosed?
Some
knee problems can be hard to tell apart. Your doctor will ask questions about
your past health and carefully examine you to rule out other conditions. Some
of the questions might be: When and how did the pain start? Did it start on its
own with no direct cause? Or was the pain caused by injury, overuse, or some
other problem with the knee? The doctor will also feel and move your knee as
part of the physical exam.
You may also have imaging tests such as
X-ray,
CT scan, and
MRI.
How is it treated?
You can try home treatment if
your knee is not swollen, dislocated, giving way, or causing you severe pain.
Take a break from activities that cause knee pain, like squatting, kneeling,
running, and jumping. Put ice on your knee, and use pain medicines you can buy
without a prescription.
As your knee pain starts to decrease,
begin stretching and strengthening your leg. Strengthening your thigh muscles
can help keep the kneecap stable. Your doctor or physical therapist can help
you plan an exercise program specifically for your condition. You will probably
start with one or two exercises and add others over time. It is important to
closely follow the instructions from your doctor or physical therapist.
Knee pain can be a slow and frustrating condition to heal. But most
people with pain from patellar tracking disorder gain relief with a few months
of treatment and without surgery. As a rule, the longer you have had this
problem, the longer it will take to get better.
Most people can
gradually return to their previous activity level if they:
- Avoid movements that make symptoms
worse.
- Do specific stretches and muscle-conditioning exercises.
- Lose excess weight.
- Tape or brace the knee, in some
cases.
- Learn the best way to perform a sport, and wear the right
shoes or equipment.
Surgery is usually not needed for patellar tracking
disorder. It is most often used when dislocation happens many times or other
treatments have not worked. There are many types of surgery that can realign
the kneecap and correct the tracking problem in some people. You and your
doctor can decide which surgery is best for you.
How can patellar tracking disorder be prevented?
You may be able to prevent patellar tracking disorder and related knee
pain. Avoid activity that overloads and overuses the knee. Stretch your legs
and hips well, both before and after activity. Cycling and swimming are
especially good activities. Stay at a healthy weight to reduce stress on your
knee joints.
Frequently Asked Questions
Learning about patellar tracking disorder: | |
Being diagnosed: | |
Getting treatment: | |
Ongoing concerns: | |
Living with patellar tracking disorder: | |
Cause
A combination of things is usually
responsible for
patellar tracking disorder. These things can
include:
- How your body is formed. The patellar tendon connects the bottom
edge of the patella to the front of the shinbone. When the patellar tendon is very long, the patella can slide too high on the knee joint. Other physical
traits that increase your risk of having knee problems include a patellar
shape that is unusually small or flat, flat feet, hips set more to the outside
of the knees than usual, a shallow femoral groove for the patella to glide
along, or a knock-knee position.
- Weak thigh muscles. Strong thigh
muscles (quadriceps) anchor the kneecap (patella) in place. Weak quadriceps
allow the patella to move off track. See a picture of the
muscles and tendons related to patellar tracking disorder.
- An
imbalance in the contraction of the thigh muscles. Your quadriceps are a group
of four muscles. If the outer muscle is stronger than the inner muscle, or if
it tends to contract quicker than the inner muscle, your kneecap can be pulled
toward the outside as your leg straightens.
- Tendons and muscles in
the leg, foot, or hip areas that are too tight or too loose. For example, weak
quadriceps combined with tight
hamstrings and a tight
iliotibial (IT) band can pull the patella toward the
outside of the knee.
- A blow to the kneecap, causing it to shift
(partially dislocate or sublux) or
dislocate. Dislocation can also be caused by twisting
the thigh inward while the foot is firmly planted, pointing outward. After an
initial dislocation, the patella is at increased risk of dislocating more
easily.
- A previous injury that has healed improperly, causing an
imbalance in how the leg functions.
- Generalized ligamentous laxity,
or "loose-jointedness." Joint instability results from ligaments that are not
as tight as they should be.
Symptoms
Symptoms of
patellar tracking disorder can include:
- A dull ache under, around, and/or at the outer
edges of the kneecap, sometimes called
patellofemoral pain syndrome. This is often made worse
by using the stairs (especially going down stairs), sitting for long periods,
and squatting.
- A popping, grinding, slipping, or catching of the
kneecap as the knee bends or extends. A grinding or popping sensation may
develop before painful symptoms start or may not occur at all. If you have
kneecap popping or grinding without pain, see the Prevention section of this
topic for stretching and strengthening exercises.
- Swelling of the
knee, in some cases.
- The knee buckling or "giving way," as though
the knee suddenly won't support your weight.
Knee pain has many causes. If you have knee pain when you
are squatting, standing up from a sitting position, going down stairs, or
sitting, you may have patellar tracking disorder. But
other conditions cause symptoms similar to those of patellar tracking
disorder. For more information on other causes of knee symptoms, see the topic
Knee Problems and Injuries.
What Happens
Patellar tracking disorder is a condition that disrupts the normal function of the knee.
Normal kneecap function
As your knee straightens
and bends, the kneecap (patella) glides up and down the femoral groove at the
front end of the thighbone (femur). At the same time, the patella tilts and
rotates slightly, held in check by
ligaments on the sides and
tendons on the top and bottom.
See a
picture of the
knee joint.
Kneecap instability
The kneecap can shift, tilt, or rotate off track (sublux) if:
- The femoral groove is shallow.
- The patella is small or flat.
- The patellar tendon is too long.
- The stabilizing ligaments,
tendons, or muscles are too tight or too loose.
And as you bend your knee to a 90-degree angle, a
misaligned kneecap will have increasing abnormal contact with the thighbone,
creating painful pressure.
In extreme cases, the kneecap can
dislocate. After a kneecap has been dislocated once,
it may dislocate more easily in the future. Any resulting damage to the kneecap
or supportive tissue can lead to ongoing patellar tracking problems.
Untreated patellar tracking disorder can lead to:
A blow to the middle or inside of a structurally sound
kneecap can also dislocate the kneecap.
What Increases Your Risk
Some risk factors (things that increase your risk) for
patellar tracking disorder are beyond your control.
Others, such as having weak quadriceps, you can change.
Things that you cannot change
- Family history of knee
problems.
- Knee abnormalities, such as knock-knees, a shallow femoral groove, a small or flat patella, or an excessively
long patellar tendon that allows the patella to slide too high on the knee
joint (patella alta).
- A
poorly healed injury of the hip, leg, knee, or foot.
- Previous
kneecap dislocation.
- Previous knee surgery.
- Generalized
ligamentous laxity, or "loose-jointedness."
- Damage to cartilage.
Things that you can avoid or change
- Weak thigh muscles
(quadriceps).
- The outer part of your thigh muscle is stronger or
contracts quicker than the inner thigh muscle.
- Tight ligaments,
tendons, and muscles.
- Excessive body weight.
- Running,
particularly on hills.
- Playing sports that require repeated
jumping, knee bending, or squatting.
- Improper
footwear.
- Improper technique and/or lack of adequate training for sports or other activities.
When To Call a Doctor
Call your doctor immediately if you have severe knee pain or your kneecap has
dislocated.
If your doctor hasn't
determined that you have
patellar tracking disorder but you have knee pain or
dysfunction, see the topic
Knee Problems and Injuries to evaluate your symptoms.
Watchful waiting
If your knee aches or your kneecap shifts or
catches, first try the stretching and strengthening exercises and other tips in
the Home Treatment section of this topic. If your symptoms continue longer than
1 to 2 weeks or if your knee is swollen, talk to your doctor.
Who to see
The following health professionals can do initial
diagnosis and treatment for patellar tracking disorder or dislocation of the
kneecap:
For instruction in strengthening, stretching, bracing,
and taping techniques, see a
physical therapist.
For evaluation of
whether a dislocated kneecap could benefit from surgery, see an
orthopedic surgeon (orthopedist) or
sports medicine specialist. For more information, see
the Surgery section of this topic.
To prepare for your appointment, see the topic Making the Most of Your Appointment.
Exams and Tests
Patellar tracking disorder can be hard to distinguish from other knee problems. If
your knee still has pain after 2 weeks of stretching, strengthening, and rest
from aggravating activity, your doctor will:
- Review your health history, including the
history of your knee problem, your current physical activities, previous
injuries, and family history of knee problems.
- Do a
physical exam of your knee and the muscles,
ligaments, and tendons that support it.
Tests that are done as needed
If your diagnosis is
unclear, you may have an X-ray, which
is the standard test for assessing the position and condition of
the knee bones. If your doctor needs more information, you may have a CT scan to look at the joint in more detail or an MRI to evaluate cartilage or ligament damage.
Treatment Overview
Knee pain can be a slow and
frustrating condition to heal. But most people with patella-related knee pain
gain relief with a few months of nonsurgical treatment. In general, the longer
you have had a
patellar tracking disorder, the longer you can expect
to be in treatment.
Self-care
Unless your knee is swollen,
dislocated, giving way, or causing you severe pain,
try the measures described in
Home Treatment for a week or two before deciding whether to see your
doctor. With rest from aggravating activity, ice, and
nonsteroidal anti-inflammatory drugs (NSAIDs), you can
expect your pain to decrease. After 2 or 3 days of using ice, you can try heat to see if it helps.
As your pain starts to subside, begin stretching and strengthening
exercises. These will loosen tight connective tissue that can pull the patella off
track. Also, the exercises will help stabilize the patella in the femoral groove as you bend and
straighten your knee.
Patellar Tracking Disorder: Exercises
Medical treatment
If home treatment isn't enough
to reduce your knee problems, or if your knee is swollen, dislocated, giving
way, or causing you severe pain, see your doctor for evaluation. Knee problems
are often hard to distinguish from one another. So a thorough exam and
accurate diagnosis are essential for you to get proper treatment.
After confirming that you have a patellar problem, your doctor will
review your home treatment measures and make further recommendations. You may
be advised to have
physical therapy, use shoe inserts
(orthotics), stabilize your knee with tape or a soft brace, or lose excess
weight.
Surgery is not commonly done for patellar tracking
disorders. But surgery is recommended in cases of repeated patellar
dislocation, displaced or damaged cartilage following
a dislocation, loose bodies (such as small pieces of bone or
cartilage) in the knee following a dislocation,
repeated
subluxations caused by a structural deformity, or
failed nonsurgical therapy.
What to think about
Nonsurgical treatment—including
stretching and strengthening exercises, temporary use of nonsteroidal
anti-inflammatory drugs, and sometimes bracing or orthotics—usually eases the
pain of a patellar tracking disorder and makes surgery unnecessary. Keeping
your knee strong and flexible will help to prevent further problems. Staying at
a healthy weight to decrease stress around your knees may also help. For more
information, see the topic
Weight Management.
Prevention
To prevent
patellar tracking disorder and related knee pain, try
to:
- Avoid activity that overloads and overuses the
knee.
- Keep the muscles around your knees and hips strong and flexible.
- Engage in other activities or exercises that work different parts
of the legs (cross train), especially if you are a runner. Cycling and swimming
are especially good activities for building other muscle groups and reducing
the stress on your knee.
- Stretch your legs and your hips well, both
before and after activity.
- Stay at a healthy weight to reduce
stress on your knee joints.
- Use proper footwear, technique, and
training for your sport or activity.
Home Treatment
If you have achy knee pain on or around
your kneecap and have not yet been diagnosed with a
patellar tracking disorder, first try the following
home treatment:
- Take a break from activities that cause knee
pain, particularly squatting, kneeling, running, and jumping. Swimming and
cycling are good aerobic choices.
- Ice your knee regularly, particularly before and after activity. After 2 or 3 days of using ice, you can try heat to see if it helps.
- Use
nonsteroidal anti-inflammatory drugs (NSAIDs) to
reduce pain and swelling.
You may also want to try:
- Wearing a soft brace with a patellar
cutout, if you feel that your kneecap is shifting enough to need
stabilizing.
- Using supportive shoe inserts (orthotics). You can buy
good-quality inserts from a shoe store or drugstore.
As your knee pain starts to go away, begin stretching and
strengthening your leg. Stretching can loosen tight muscle and connective
tissue that have been pulling the patella off track. Strengthening your thigh
muscles can help stabilize the patella in the femoral groove as you bend and
straighten your knee.1
- Stretch your thigh muscles (quadriceps),
hamstrings,
iliotibial (IT) band, and
Achilles tendon daily, particularly before and after
activity.
- Begin thigh strengthening with isometric exercise and
straight leg raises only. Progress to exercises such as quarter squats and leg
presses, in which your feet are pushing against something (closed-chain
exercises). Avoid knee-extension exercises in which you are raising and
lowering your foot, which may further damage your unstable knee.
- Patellar Tracking Disorder: Exercises
Surgery
Surgery is considered appropriate only for
chronic and severe cases of
patellar dislocation and select cases of chronic
patellar tracking disorder. Surgery can be used to
realign the kneecap and restore normal patellar tracking and to repair knee
damage.
Surgery choices
The type of surgery that is appropriate for you depends
on the type of tracking disorder you have and its cause. Surgeries for patellar
tracking disorder include:
What to think about
Surgeons use different
procedures for repairing knee problems. The procedure used depends on the cause
of your knee problem and your surgeon's experience.
Some surgeons think it best in some cases to repair knee damage
immediately after a first
patellar dislocation. Other surgeons will wait until
they see a recurrent problem.
Although surgery for dislocation
offers a good chance that the patella will no longer dislocate, many people
continue to have pain after surgery. There is no
proof that surgery to make the knee joint more stable will prevent long-term
joint changes such as osteoarthritis.2
Other Treatment
Other treatments are often used
for
patellar tracking disorder. Before using other
treatments, first try home treatment to reduce pain and inflammation.
Other treatment choices
Try
physical therapy to:
- Receive personal instruction for the stretching and
strengthening exercises that are important for treating your
knee.
- Learn a specialized taping technique for holding an unstable
kneecap in place. Ask your physical therapist about using tape to help your kneecap move properly during exercise and activity.
If your doctor recommends it, be fitted for a nonprescription or prescription (custom)
knee brace or shoe inserts (orthotics) for extra knee support or to
improve the position of your feet. If you try orthotics, use them in both shoes even if only one knee hurts.
In addition to stretching and strengthening, you can also
try massage to improve circulation and healing.
What to think about
Before investing in a custom
brace or orthotics, try over-the-counter versions from a sporting goods supply
or drugstore.
Other Places To Get Help
Organization
| American Academy of Orthopaedic Surgeons
(AAOS) |
| 6300 North River Road |
| Rosemont, IL 60018-4262 |
| Phone: | (847) 823-7186 |
| Fax: | (847) 823-8125 |
| Email: | orthoinfo@aaos.org |
| Web Address: | www.orthoinfo.aaos.org |
| |
The American Academy of Orthopaedic Surgeons (AAOS)
provides information and education to raise the public's awareness of
musculoskeletal conditions, with an emphasis on preventive measures. The AAOS
website contains information on orthopedic conditions and treatments, injury
prevention, and wellness and exercise. |
|
References
Citations
- Hertling D, Kessler RM (2006). Knee. In Management of Common Musculoskeletal Disorders: Physical Therapy Principles and Methods, 4th ed., pp. 487–557.
Philadelphia: Lippincott Williams and Wilkins.
- Mulford JS, et al. (2007). Assessment and management
of chronic patellofemoral instability. Journal of Bone and Joint Surgery, British Volume, 89-B(6): 709–716.
Other Works Consulted
- American Academy of Family Physicians (2010).
Patellofemoral pain syndrome. Available online:
http://familydoctor.org/online/famdocen/home/healthy/physical/injuries/479.html.
- American Academy of Podiatric Sports Medicine (2004).
Patellofemoral Dysfunction. Available online:
http://www.aapsm.org/patellofemoraldys.html.
- Earl JE, Vetter CS (2007). Patellofemoral pain.
Physical Medicine and Rehabilitation Clinics of North America, 18(2007): 439–458.
- Grudziak JS, Musahl V (2007). Patella instability and
dislocation in adolescents section of The youth athlete. In PJ McMahon, ed.,
Current Diagnosis and Treatment in Sports Medicine, p.
230. New York: McGraw-Hill.
- Hudgins T (2008). Patellofemoral syndrome. In WR Frontera et al., eds., Essentials of Physical Medicine and Rehabilitation: Musculoskeletal Disorders, Pain, and Rehabilitation, 2nd ed., pp. 371–374. Philadelphia: Saunders Elsevier.
- Rauh MA, Parker RD (2010). Patellar and quadriceps tendinopathies and ruptures. In JC DeLee et al., eds., DeLee and Drez's Orthopaedic Sports Medicine: Principles and Practice, 3rd ed., vol. 2, pp. 1513–1525. Philadelphia: Saunders Elsevier.
- Van Linschoten R, et al. (2009). Supervised exercise therapy versus usual care for patellofemoral pain syndrome: An open label randomised controlled trial. BMJ. Published October 20, 2009 (doi:10.1136/bmj.b4074).
- Warden SJ, et al. (2008). Patellar taping and bracing
for the treatment of chronic knee pain: A systematic review and meta-analysis.
Arthritis and Rheumatism, 59(1): 73–83.
Credits
| By | Healthwise Staff |
|---|
| Primary Medical Reviewer | William H. Blahd, Jr., MD, FACEP - Emergency Medicine |
|---|
| Specialist Medical Reviewer | Patrick J. McMahon, MD - Orthopedic Surgery |
|---|
| Last Revised | January 9, 2012 |
|---|
