Patellar Dislocation

Patellar dislocation, also known as kneecap dislocation, is a medical condition where the patella (kneecap) slips out of its normal position in the groove at the end of the thigh bone (femur). This can be a painful and debilitating injury that affects the knee joint.

Causes

The causes of patellar dislocation can be traumatic or non-traumatic. Traumatic causes include:

• Direct blow to the knee, such as from a fall or sports injury
• Sudden twisting motion of the knee
• Severe hyperextension of the knee joint

Non-traumatic causes include:

• Weak quadriceps muscles or tight hamstring muscles, which can lead to poor tracking of the patella in its groove
• Trochlear dysplasia, a condition where the groove at the end of the femur is shallow or irregularly shaped
• Patellofemoral pain syndrome, a condition characterized by chronic knee pain and instability

Symptoms

The symptoms of patellar dislocation can vary depending on the severity of the injury. Common symptoms include:

• Sudden onset of severe knee pain
• Instability or feeling of the kneecap slipping out of place
• Swelling and bruising around the knee joint
• Difficulty walking or bearing weight on the affected leg
• Abnormal appearance of the knee, with the patella visible out of its normal position

Diagnosis

Diagnosis of patellar dislocation is typically made through a combination of physical examination and imaging studies. The doctor may:

• Perform a physical examination to assess knee stability, range of motion, and pain
• Order X-rays to rule out fractures or other bony abnormalities
• Order an MRI (magnetic resonance imaging) scan to evaluate the soft tissues, including ligaments and cartilage
• Order a CT (computed tomography) scan to further evaluate the bony structures of the knee joint

Treatment

Treatment for patellar dislocation depends on the severity of the injury and may include:

• Reduction, where the doctor manually moves the patella back into its normal position
• Immobilization in a knee brace or cast to allow healing and stabilization of the joint
• Physical therapy to strengthen the quadriceps muscles and improve knee stability
• Pain management with medication, such as pain relievers or anti-inflammatory medications
• Surgery, which may be necessary for severe injuries or recurrent dislocations, to repair damaged ligaments or realign the patella

Complications

Complications of patellar dislocation can include:

• Chronic knee instability and recurrent dislocations
• Persistent pain and stiffness in the knee joint
• Cartilage damage or osteoarthritis, which can lead to long-term degenerative changes in the knee joint
• Nerve or blood vessel damage, although rare, can occur with severe injuries

Prevention

To prevent patellar dislocation, it is essential to:

• Maintain strong quadriceps muscles through regular exercise and physical therapy
• Avoid activities that involve repetitive knee bending or twisting
• Use proper technique when participating in sports or other physical activities
• Wear protective gear, such as knee pads, to reduce the risk of injury

Frequently Asked Questions (FAQs)

What is patellar dislocation?
Kneecap slips out of place.

What causes patellar dislocation?
Trauma, injury, or abnormal knee structure.

What are symptoms of patellar dislocation?
Pain, swelling, and kneecap instability.

How is patellar dislocation diagnosed?
Physical exam and imaging tests like X-rays.

Can patellar dislocation be treated without surgery?
Yes, with bracing, physical therapy, and pain management.

What are risks of recurrent patellar dislocation?
Further knee damage and chronic instability.

How long does recovery from patellar dislocation take?
Several weeks to months.

Can patellar dislocation be prevented?
Strengthening surrounding muscles may help.

Is surgery necessary for patellar dislocation?
Sometimes, to repair or realign the kneecap.

What are potential complications of patellar dislocation?
Chronic pain, arthritis, and limited knee function.