Synergy Health Partners

Musculoskeletal Care, Reimagined


A dislocated knee cap, also known as patellar dislocation, occurs when the patella (knee cap) slips out of its normal position in the patellofemoral groove of the femur (thigh bone). This injury is often caused by trauma or sudden twisting movements and can result in pain, swelling, and difficulty moving the knee.


The primary causes of a dislocated knee cap include:

  • Trauma: A direct blow to the knee, such as during a fall or sports collision.
  • Twisting Movements: Sudden changes in direction or twisting motions of the knee.
  • Structural Abnormalities: Anatomical factors such as a shallow patellofemoral groove, high-riding patella (patella alta), or misalignment of the leg bones.
  • Weakness or Imbalance: Weakness or imbalance in the muscles surrounding the knee, particularly the quadriceps and hip muscles.


Symptoms of a dislocated knee cap can include:

  • Severe Pain: Immediate and intense pain in the knee.
  • Visible Deformity: The patella may be visibly out of place, often shifted to the outside of the knee.
  • Swelling and Bruising: Rapid swelling and bruising around the knee.
  • Inability to Move the Knee: Difficulty or inability to straighten or bend the knee.
  • Instability: A feeling of the knee giving way or being unstable.


Diagnosis of a dislocated knee cap involves a combination of clinical evaluation and imaging studies:

  • Medical History and Physical Examination: Assessment of symptoms, injury history, and physical examination to check for patellar displacement and knee stability.
  • Imaging Studies: X-rays to confirm the dislocation and rule out associated fractures. MRI may be used to assess soft tissue damage, such as ligament tears or cartilage injury.


Treatment for a dislocated knee cap typically involves:

  • Reduction: A healthcare professional will gently manipulate the patella back into its correct position. This procedure, called reduction, is often performed under sedation or local anesthesia.
  • Immobilization: After reduction, the knee is immobilized with a brace or splint to allow the ligaments and soft tissues to heal. The immobilization period usually lasts for 2-3 weeks.
  • Ice and Elevation: Applying ice to the injured knee and elevating it to reduce swelling and pain.
  • Medications: Pain relievers and anti-inflammatory medications to manage pain and inflammation.


Rehabilitation is crucial for restoring knee function and preventing future dislocations:

  • Physical Therapy: A structured physical therapy program focuses on strengthening the quadriceps, hamstrings, and hip muscles, as well as improving flexibility and knee stability.
  • Range of Motion Exercises: Gradual reintroduction of knee movements to restore full range of motion.
  • Proprioception Training: Exercises to enhance balance and coordination, reducing the risk of re-injury.
  • Activity Modification: Avoiding activities that put excessive strain on the knee during the recovery period.

Surgical Treatment

Surgery may be necessary in cases of recurrent dislocations or when there is significant damage to the knee structures:

  • Lateral Release: Cutting tight structures on the outer side of the patella to allow it to move back into place more easily.
  • Medial Patellofemoral Ligament (MPFL) Reconstruction: Reconstructing the ligament that stabilizes the patella.
  • Osteotomy: Realigning the bones to improve patellar tracking.


The prognosis for a dislocated knee cap varies depending on the severity of the injury and the effectiveness of treatment. With proper management, most individuals can expect to recover fully and return to their normal activities. However, some may experience recurrent dislocations, requiring further treatment.


Preventing patellar dislocation involves:

  • Strengthening Exercises: Regular exercises to strengthen the quadriceps, hamstrings, and hip muscles.
  • Proper Technique: Using proper techniques in sports and physical activities to reduce the risk of knee injuries.
  • Protective Gear: Wearing appropriate protective equipment during high-risk activities.
  • Maintaining a Healthy Weight: Reducing excess stress on the knees by maintaining a healthy weight.


A dislocated knee cap is a painful and potentially debilitating injury that requires prompt and appropriate treatment to ensure proper healing and prevent future dislocations. If you experience symptoms of a dislocated patella, seek immediate medical attention for a thorough evaluation and personalized treatment plan. Early intervention and rehabilitation are key to achieving the best possible outcome and returning to normal activities.