Patellar dislocations are categorized according to cause and progression as follows:

1. Acute traumatic dislocation: Occurs as a result of direct trauma or sudden force impact.
2. Recurrent dislocation: Repeated dislocation of the kneecap, often due to misalignments or unstable ligaments.
3. Congenital dislocation: Congenital misalignment of the kneecap, diagnosed in childhood.

The causes of a patellar dislocation are varied and can be mechanical, anatomical, or genetic in nature:

• Traumatic events:
  • Sudden lateral force, such as from a fall or blow to the knee.
• Anatomical factors:
  • Misalignments such as knock-knees, a high patella position (patella alta), or a shallow trochlea (patellar groove).
• Ligament instability:
  • Weakness or injuries of the medial patellofemoral ligament (MPFL), which stabilizes the patella.
• Muscle imbalances:
  • Uneven pulling forces of the thigh muscles, which can pull the patella out of position.
• Genetic predisposition:
  • Familial occurrence of patellar dislocations suggests a genetic component.

The symptoms of a patellar dislocation are characteristic and include:

• Acute pain: Severe pain in the area of the kneecap, especially immediately after the dislocation.
• Deformity: Visible displacement of the patella, usually to the outside of the knee.
• Swelling: Rapid swelling due to bruising in the joint (hemarthrosis).
• Instability: Feeling of "giving way" or insecurity in the knee, especially during movement.
• Limited range of motion: Difficulty in extending or bending the knee.

The diagnosis is made through medical history, clinical examination, and imaging techniques:

1. **Medical History:** Collection of the patient's medical history, description of symptoms, and circumstances of the injury.

2. **Clinical Examination:**

- Checking the position of the kneecap and the stability of the surrounding structures.

- Tests such as the apprehension test, where lateral displacement pressure on the patella is checked.

3. **Imaging Techniques:**

- **X-ray:** Visualization of bone injuries and misalignments.

- **MRI:** Examination of soft tissue damage, such as injuries to the MPFL or cartilage damage.

- **CT:** Detailed assessment of anatomical deviations and fractures.

Conservative Therapy

In cases of initial or mild patellar dislocation, conservative treatment may be sufficient:

• Reposition:
  • Manual repositioning of the patella to its natural position, usually by a doctor.
• Immobilization:
  • Use of knee braces or splints to stabilize the joint and promote healing.
• Physiotherapy:
  • Exercises to strengthen the thigh muscles and improve stability.
• Cold Applications:
  • Reduction of pain and swelling through cold packs.
• Medication Therapy:
  • Intake of NSAIDs for pain relief and anti-inflammation.

Surgical Therapy

In cases of repeated dislocations or significant damage, surgical intervention may be necessary:

• MPFL Reconstruction:
  • Restoration or reinforcement of the medial patellofemoral ligament.
• Trochleoplasty:
  • Surgical deepening of the groove to improve patellar tracking.
• Tibial Tuberosity Transfer:
  • Modification of the patellar tendon attachment site to correct the pull direction.
• Cartilage Reconstruction:
  • Treatment of accompanying injuries such as cartilage damage.

The following measures are helpful in preventing a patellar dislocation:

1. Strengthening the muscles: Regular training of the thigh muscles to stabilize the kneecap.
2. Avoiding overexertion: Limiting intense sports activities, especially those with sudden changes in direction.
3. Correction of misalignments: Use of insoles or orthoses to improve leg alignment.
4. Coordination training: Exercises to improve balance and proprioception.
5. Early detection and treatment: Timely examination at the first signs of instability or pain in the knee.