Patellofemoral Arthralgia - MedFriendly.com

The femoral condyles are a large pair of prominences at the farthest end of each femur. The femur is the

long bone of the leg that runs from the hip to the knee. The femoral condyle is pictured above.

If the groove between the condyles is not deep enough or the facets of the kneecap are deformed,

patellofemoral arthralgia can result. Specifically, all of the structural abnormalities mentioned above can

cause too much pressure between the kneecap and femoral condyles during flexing and extending

movements.

The second possible cause of patellofemoral arthralgia is gradual wear and tear caused by tiny daily

repetitive stresses (overuse). A common activity leading to such overuse is running. When the pain

occurs at the area where the femur and patella join together (see above) the source is likely irritation of

the many nerves located in the subchondral bone (bone below the cartilage) of the patellae. This is

because cartilage does not have pain fibers. Cartilage is a type of soft, flexible tissue that helps form

many important body structures.

In some patients, soft tissue around the kneecap may be the source of the pain, especially in young

active patients where there is mild misalignment of the kneecap (also known as the patella). In these

cases, strain on tendons can produce inflammation and pain.

WHAT ARE COMMON CLINICAL FINDINGS IN PATELLOFEMORAL ARTHRALGIA?

When the physician squeezes the middle or side facets on the back surface of the kneecap, this may

cause pain. The physician may squeeze these facets while mildly displacing the kneecap to the middle or

the side. Squeezing the kneecap onto the femoral condyles may cause characteristic discomfort. When

both sides of the kneecap are grasped while the patient contracts the quadriceps muscle, the added

pressure of the kneecap against the femoral condyles may cause discomfort.

WHO GETS PATELLOFEMORAL ARTHRALGIA?

Patellofemoral arthralgia is common in people who regularly engage in competitive or recreational

activities. It is most common in adolescents and young adults. Females appear to be affected more than

males. This may be because females have a wider pelvis, which leads to an exaggerated Q angle. The

Q angle is the angle by which the quadriceps muscles pull at the knee. The Q angle is typically about 15

degrees in adults. Some have questioned the relevance of the Q angle in patellofemoral arthralgia.

WHAT IS THE DIFFERENCE BETWEEN PATELLOFEMORAL ARTHRALGIA AND

CHONDROMALCIA PATELLAE?

Chondromalacia patellae is a painful disorder of the knee in which the cartilage directly behind the

kneecap becomes soft and damaged. The type of cartilage affected in chondromalacia patellae is called

articular cartilage. The word "articular" means "referring to a joint." A joint is a place where two bones

contact each other. In most cases of patellofemoral arthralgia, the articular cartilage is not injured. There

is little evidence that untreated patellofemoral arthralgia leads to chondromalacia patellae.

Patellofemoral arthralgia may spontaneously resolve by itself although many patients have tried a wait

and see approach before pursuing treatment. One form of treatment is relative rest. The term relative

rest is used because it means that the person can still be active but should be doing non-impact aerobic

activities that do not risk injuring the knee.

In addition to relative rest, physical therapy is commonly recommended, with special emphasis placed

upon strengthening the quadriceps muscle. Stretching exercises are also used. The decision of which

exercises to perform depends on an accurate physical examination. Twenty minutes of physical therapy

a day is considered reasonable by many. Symptom improvement with exercise may take up to 6 weeks.

Yet another form of treatment includes using a different quality of shoe, with the major factor being that

the shoe is not worn out. For example, some runners change their shoes every 300-500 miles. Arch

supports or custom made foot inserts may be helpful and are fairly inexpensive.

Ice is sometimes used to reduce inflammation, especially after activity. This is usually accomplished by

placing an icepack over the knee and holding it in place with an elastic band. Other options include a

frozen gel pack, crushed ice in a plastic bag, or a bag of frozen vegetables. Some people try non-

steroidal anti-inflammatory drugs (known as NSAIDs), but there is no proven benefit from this and there

is always the concern of side effects.

Some people use knee sleeves or knee braces to stabilize the kneecap. However, the use of such

devices is controversial since it has not been proven to work and is not considered a substitute for

physical therapies. Some people tape the kneecap to keep it stable. This may offer short term pain relief.

Most physical therapists are trained in taping methods and can teach patients how to do this themselves.

Most patients do well with non-surgical forms of treatment, especially if they are disciplined. Surgery for

patellofemoral arthralgia is only used as a last resort. Surgery involves cutting the lateral (side)

retinaculum to decrease the amount that the kneecap is pulled to the side. This type of surgery is known

as lateral release.

WHAT ELSE IS PATELLOFEMORAL ARTHRALGIA KNOWN AS?

Patellofemoral arthralgia is also known as retropatellar pain syndrome, patellofemoral pain syndrome,

extensor mechanism disorder, lateral patellar compression syndrome, patellalgia, and patellofemoral

dysfunction.

WHY IS IT CALLED PATELLOFEMORAL ARTHRALGIA?

Patellofemoral arthralgia comes from the Latin word "patella" meaning "kneecap," the Latin word “femur”

meaning “thigh,” the Greek word “arthron” meaning “joint,” and the Greek word "algos" meaning "pain."

Put the two words together and you have "kneecap thigh joint pain."