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Knee and Kneecap Problems

What are common kinds of kneecap problems?

Many different problems can affect the kneecap (patella), the disc of bone that protects the knee joint and helps the thigh muscles move the knee.

The kneecap is one of three bones in the knee. The others are the shinbone (tibia) and the thighbone (femur). The kneecap sits within a tendon at the end of the thighbone, near the front thigh muscle (quadriceps).

Sometimes the kneecap is sitting in an unbalanced way, usually too far toward the outside of the knee. This can cause the kneecap to slip out of the joint, or put more pressure on the thighbone and the cartilage in the knee. All of these problems can cause pain.

Tight thigh muscles can also lead to knee and kneecap pain. If the quadriceps is tight, the kneecap gets pushed hard against the thighbone. Tight muscles on the back of the thighs (hamstrings) force the quadriceps muscle to work harder, which may cause kneecap pain.

In children, spots on the bones around the knee that contribute to growth are weaker than other surrounding bone. If the growth centers become inflamed or irritated it can cause pain.

When this happens at the top of the shinbone, the problem is called Osgood-Schlatter disease. When it happens at the bottom of the kneecap, it is called Sinding-Larsen-Johansson syndrome.

How do you evaluate kneecap problems?

Point of maximum tenderness.
Point of maximum tenderness.

When you visit our clinic, we will ask detailed questions about the pain your child is feeling, and about any incidents or accidents that may have happened before his knee began to hurt.

Sudden swelling after an injury is a sign of trouble, so we will examine your child’s knee.

We will probably take X-rays. We may also take pictures of your child’s legs as he stands still. This will help us spot any tendency in your child toward knock-knees, a condition that makes pain more likely.

If we need more information, we may ask your child to have an MRI or CT scan to see whether there is damage to the cartilage inside his knee or get a better look at the position of his kneecap.

Who gets kneecap problems?

Growing children and adolescents, particularly teenage girls, have pain around their kneecaps. Children whose knees are bent inward — commonly called knock-kneed — also tend to have the problem. So do children with tight thigh muscles.

How do you treat kneecap problems?

Correcting or improving kneecap problems can be very difficult. At Children’s Hospital, we specialize in treating children who are growing and tailoring treatment to the problem.

We emphasize physical therapy and home exercise programs for most cases of kneecap pain. These programs strengthen muscles around the knee so that the kneecap stays in place.

Exercises to strengthen the medial quadriceps muscle are especially important to treating kneecap problems successfully. When this muscle is strong, it helps keep the kneecap tracking correctly.

Surgery for kneecap problems

If your child is severely knock-kneed or has kneecaps that tend to slide out of the joint (dislocate), he may benefit from surgery to help line up his knees and lower legs.

There are a number of surgical approaches to treating kneecaps that tend to dislocate. For children who are knock-kneed, temporarily placing staples in the medial growth plate at the lower end of the thighbone can correct the problem.

This procedure lets the outer growth plates grow while pinching the inner growth plates, which tends to straighten legs over time and improve the kneecap’s tracking.

Older children may benefit from an operation that ties the kneecap down to the inner side of the knee, keeping it from sliding to the side.

Another option is to move the attachment of the kneecap to the shinbone so that the kneecap tracks better.

Surgery also may be the best treatment if your child has dislocated his kneecap and injured the cartilage covering the joint.

In this operation, which is usually minimally invasive, the doctor tries to re-attach cartilage and bone where they have been knocked out of place by the dislocating kneecap.