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