Dislocation of the Patella

What is Patella Dislocation?

The patella is also known as the kneecap. It serves as a protective bone in front of the knee joint. The kneecap glides up and down the patellofemoral groove at the front of the thigh bone (femur) as the knee bends. The quadriceps and patella are attached via the quadriceps tendon and act to increase the leverage from this muscle group when straightening the knee.

The patella is designed to run vertically up and down the patellofemoral groove. If the patella is moved to the outside of the groove it may become dislocated. This is often the result of an acute blow / twisting action of the knee. In most cases the patella will relocate the patellofemoral groove on straightening of the knee, however this is known to be extremely painful.

What factors can lead to Patella Dislocation?

• Weak VMO - The VMO ( vastus medialis oblique muscle) is acts to pull the knee cap inwards - an action known as 'tracking'. Weakness in this muscle may leave the patella far more susceptible to dislocation.
• Pronation of the feet.
• Q-angle - Some people have a larger than normal femoral angle (known as the Q-angle) resulting in a 'knock-kneed' appearance (genu valgum). When the person straightens their leg, the patella will be forced to the outside of the knee. Thus any extra force applied to the inside of the knee may result in patellar dislocation.

Symptoms of Patella Dislocation:

• Obvious displacement of the knee cap
• The knee may be swollen
• The patella will be painful
• Reduced mobility in the knee

How can the athlete treat this injury?

• Cold therapy and rest (R.I.C.E.)
• Immediately see a medical professional
• Use of a support or heat retainer
• Take a glucosamine / joint healing supplement.
• Follow a rehabilitation program..

Visiting a Sports Injury Specialist:

• Confirm the diagnosis.
• Reduce the pain by anesthetic and reposition the patella if it has not already relocated.
• Cryotherapy (ice treatment)
• Exercises to strengthen the VMO
• Anti-inflammatory medication may be prescribed.
• Patellofemoral taping techniques
• Prescribe VMO strengthening exercises.
• Examine the injury by X-ray and/or arthroscopy to evaluate the extent of the injury.
• Operation may be necessary if there are loose fragments of bone or other major structural damage.

Useful Products:

• Cold Therapy Wraps - apply cold therapy treatment to the site of injury to help relieve pain and swelling.
• Knee Braces - a patella knee support can aid with patella tracking and reduce the risk of further injury.

Please see the Virtual Sports Injury Clinic for more information on how to treat Patella Dislocation and other knee injuries.