Kneecap instability and dislocation

What does kneecap instability and dislocation mean?

Kneecap instability occurs when the kneecap (patella) is misaligned, allowing it to move side to side, rather than up and down in the joint. When an unstable kneecap fully slips out of place, it’s called a dislocation.

To provide your child with the best care possible, we offer the full range of services in one convenient location, including:

• Pediatric orthopedic physicians and surgeons

• Advanced imaging technology

• Physical therapy (PT) and rehabilitation

Risk factors

Girls face a greater risk of kneecap instability and dislocation because of anatomical differences like pelvic width.

What are the signs and symptoms of kneecap instability and dislocation?

Signs and symptoms of kneecap instability and dislocation include:

• Pain

• Swelling

• Bruising

• Feeling of knee buckling or “giving out”

• Hearing a “popping” sound

• Deformity in the knee joint

• Difficulty using, moving or bearing weight on the affected leg

Sometimes, a dislocated knee may temporarily move back into place. Even if this happens, we advise parents to seek treatment as soon as possible. Your child may still have knee damage that needs comprehensive treatment.

How is kneecap instability and dislocation diagnosed?

Our physicians diagnose kneecap instability or dislocation by starting with a physical examination. They may also order imaging tests to determine the problem with your child’s knee. 

• Physical exam - Tests movement, appearance and sensation in your child’s knee joint and leg muscles

• X-ray - Uses invisible electromagnetic energy beams to take detailed images of the patella and knee’s bones

• MRI (magnetic resonance imaging) scan - Uses magnetic fields and radio waves to take detailed pictures of the knee joint, checking for tears in the ligaments, tendons and cartilage

What are the causes of kneecap instability and dislocation?

Kneecap instability and dislocation are common pediatric injuries because children’s growing bones, ligaments and tendons can make the joint unstable.

Common causes of kneecap instability and dislocation include:

• Shallow or uneven groove in the femur, where the patella sits

• Looser and more flexible ligaments — especially in girls

• Sudden, traumatic injury from a fall or physical contact

• Wear and tear from repetitive movements in sports

How is kneecap instability and dislocation treated?

At the Andrews Institute, we take a multidisciplinary approach to treating children with kneecap instability and dislocation. We bring together orthopaedic and sports medicine specialists and in-house physical therapists for your child’s ongoing care.

Treatment for kneecap instability and dislocation depends on the severity of your child’s injury. Most often, our physicians can use therapies that avoid surgery.

Nonsurgical treatments may include:

• Rest, ice, compression and elevation (RICE)

• Bracing to immobilize and promote healing

• Medication to help manage pain and swelling

• Activity modification

• Reduction, a procedure in which your child’s physician places the kneecap in its proper place for healing. Your child will receive sedation for comfort during the procedure.

• Physical therapy (PT) and rehabilitation

For chronic kneecap dislocation, we may recommend arthroscopy surgery to repair damaged muscles, tendons or ligaments. If surgery is needed, our surgeons offer a minimally invasive arthroscopic approach.