What is chondromalacia patellae?
Chondromalacia patellae, also known as “runner’s knee,” is a
condition where the cartilage on the undersurface of the patella (kneecap)
deteriorates and softens. This condition is common among young, athletic
individuals, but may also occur in older adults who have arthritis of the knee.
Chondromalacia is often seen as an overuse injury in sports,
and sometimes taking a few days off from training can produce good results. In
other cases, improper knee alignment is the cause and simply resting doesn’t
provide relief. The symptoms of runner’s knee are knee pain and grinding
sensations, but many people who have it never seek medical treatment.
What causes chondromalacia patellae?
Your kneecap normally resides over the front of your knee joint. When you bend your knee, the backside of your kneecap glides over the cartilage of your femur or thigh bone at the knee. Tendons and ligaments attach your kneecap to your shinbone and your thigh muscle to the kneecap. When any of these components fails to move properly, it can cause your kneecap to rub up against your thigh bone. This abnormal rubbing can lead to deterioration in the patella, resulting in chondromalacia patellae or runner’s knee.
Improper kneecap movement may result from:
- poor alignment due to a congenital condition
- weak hamstrings and quadriceps (the muscles in
the back and front of your thighs)
- muscle imbalance between the adductors and
abductors (the muscles on the outside and inside of your thighs)
- repeated stress to your knee joints, such as
from running, skiing, or jumping
- a direct blow or trauma to your kneecap
Who is at risk for chondromalacia patellae?
There are a variety of factors that may increase your risk for developing chondromalacia patellae.
Adolescents and young adults are at high risk for this
condition. During growth spurts, the muscles and bones develop rapidly, which
may contribute to short-term muscle imbalances.
Females are more likely than males to develop runner’s knee,
as they typically possess less muscle mass than males. This can cause abnormal
knee positioning, as well as more lateral (side) pressure on the kneecap.
Flat feet may place more stress on your knee joints than in
people who have higher arches in their feet.
A prior injury to the kneecap, such as a dislocation, can
increase your risk of developing runner’s knee.
High activity level
If you have a high activity level or engage in frequent
exercises that place pressure on your knee joints, this can increase the risk
for knee problems.
Runner’s knee can also be a symptom of arthritis, a condition
causing inflammation to the joint and tissue. Inflammation can prevent the
kneecap from functioning properly.
What are the symptoms of chondromalacia patellae?
Chondromalacia patellae will typically present itself with pain in
the knee region, known as patellofemoral pain. You may feel sensations of
grinding or cracking when bending or extending your knee. Pain may worsen after
sitting for a prolonged period of time or during activities that apply extreme
pressure to your knees, such as standing for an extended period or exercising.
Talk to your doctor if you have knee pain that doesn’t
improve within a few days.
Diagnosing and grading chondromalacia patellae
Your doctor will look for areas of swelling or tenderness in
your knee. They may also look at how your kneecap aligns with your thigh bone.
A misalignment can be an indicator of chondromalacia patellae. Your doctor may also
apply resistive pressure to your extended kneecap to determine the tenderness
Afterward, your doctor may request any of the following
tests to aid in diagnosis and grading:
- X-rays to show bone damage or signs of
misalignment or arthritis
- magnetic resonance imaging (MRI) to view
cartilage wear and tear
- arthroscopic exam, a minimally invasive
procedure involving an endoscope and camera inserted into the knee joint.
There are four grades, ranging from grade 1 to 4, that
designate the severity of runner’s knee. Grade 1 is least severe, while grade 4
indicates the greatest severity.
Grade 1 severity
indicates softening of the cartilage in the knee area.
Grade 2 designates
a softening of the cartilage along with abnormal surface characteristics. This
usually indicates the beginning of tissue erosion.
Grade 3 shows
thinning of cartilage with active deterioration of the tissue.
Grade 4, the
most severe grade, indicates exposure of the bone with a significant portion of
cartilage deteriorated. Bone exposure means bone-to-bone rubbing is likely
occurring in the knee.
Treatment options for chondromalacia patellae
The goal of treatment is to reduce the pressure on your
kneecap and joint. Resting, stabilizing, and icing the joint may be the first
line of treatment. The cartilage damage resulting in runner’s knee can often
repair itself with rest.
Your doctor may prescribe several weeks of anti-inflammatory medication, such as
ibuprofen, to reduce inflammation around the joint. If swelling, tenderness,
and pain persist, the following treatment options may be explored.
Physical therapy focusing on strengthening the quadriceps,
hamstrings, adductors, and abductors can help improve your muscle strength and
balance. Muscle balance will help prevent knee misalignment.
Typically recommended are non-weight-bearing exercises, such
as swimming or riding a stationary bike. Additionally, isometric exercises that
involve tightening and releasing your muscles can help to maintain muscle mass.
Arthroscopic surgery may
be necessary to examine the joint and determine whether there’s misalignment of
the knee. This surgery involves inserting a camera into your joint through a
tiny incision. A surgical procedure may fix the problem. One common procedure
is a lateral release. This operation involves cutting some of your ligaments to
release tension and allow for more movement.
Other surgical options may involve smoothing the backside of
the kneecap, implanting a cartilage graft, or relocating the insertion of the
Tips to prevent chondromalacia patellae
You can help reduce your risk of developing runner’s knee by
following these recommendations:
- Avoid repeated stress to your kneecaps. Wear
kneepads if you have to spend time on your knees.
- Create muscle balance by strengthening your
quadriceps, hamstrings, abductors, and adductors.
- Wear shoe inserts that correct flat feet by
increasing your arch. This will decrease the amount of pressure placed on your
knees and may realign the kneecap.
Finally, excess body weight may stress your knees.
Maintaining a healthy body weight can help take pressure off the knees and
other joints. You can take steps to lose weight by reducing your sugar and fat
intake, eating plenty of vegetables, fruits, and whole grains, and exercising
for at least 30 minutes day, five times a week.