What is the appropriate treatment for a patient with a displaced patella and hematoma after a fall?

Management of Displaced Patella with Hematoma After Fall

For a patient with a displaced patella and hematoma following a fall, immediate hemorrhage control takes priority if there is active bleeding, followed by urgent imaging (radiographs first, then CT if needed) to characterize the fracture pattern, and definitive treatment based on hemodynamic stability, fracture displacement, and extensor mechanism integrity.

Initial Assessment and Hemorrhage Control

If active limb hemorrhage is present and direct compression is ineffective, apply a tourniquet immediately 1. This is the fastest lifesaving technique when the patient presents with hemodynamic instability or no radial pulse 1. Re-evaluate tourniquet effectiveness and location as soon as possible to limit ischemic time 1.

For patients presenting with hemorrhagic shock and an identified bleeding source (the patellar hematoma), proceed to immediate bleeding control unless initial resuscitation is successful 1. Early bleeding control should be achieved using direct pressure, packing, or surgical hemostatic procedures 1.

Resuscitation Parameters

• Target systolic blood pressure of 80-100 mmHg until major bleeding is controlled (in patients without brain injury) 1
• Initiate crystalloid fluid therapy, with colloids added within prescribed limits 1
• Monitor serum lactate and base deficit to estimate and monitor the extent of bleeding and shock 1

Diagnostic Imaging Algorithm

Step 1: Plain Radiographs

Obtain AP and lateral knee radiographs immediately 1. These are the first-line imaging modality for acute knee trauma 1. Radiographs should be obtained if the patient meets Ottawa Knee Rule criteria (age ≥55 years, isolated patellar tenderness, inability to flex knee to 90°, inability to bear weight immediately or walk 4 steps) 1.

Step 2: CT Without IV Contrast

If radiographs are negative or indeterminate but clinical suspicion remains high (persistent pain, significant hematoma, inability to extend knee), proceed immediately to CT without IV contrast 2, 3. CT detects occult fractures in 24.1% of patients with negative radiographs and changes management in 20% of cases 2, 3. CT has 94% sensitivity and 100% specificity for detecting radiographically occult fractures 2, 3.

Critical pitfall to avoid: Do not rely on preserved range of motion or weight-bearing ability to exclude fracture—patients with minimally displaced fractures can maintain function initially 3.

Step 3: MRI (If Needed)

If pain or hematoma worsens or fails to improve by 2 weeks despite treatment, obtain MRI to evaluate for occult fracture, osteochondral injury, muscle tear, or hematoma requiring intervention 3, 4. MRI is essential to exclude soft tissue injuries such as ACL rupture, which commonly accompany patellar fractures 4.

Definitive Treatment Based on Fracture Pattern

For Displaced Fractures (≥1 cm displacement or disrupted extensor mechanism)

Surgical fixation with open reduction and internal fixation is the standard treatment 4, 5. Early fixation optimizes outcomes and prevents complications from delayed treatment 2, 4. Surgery should be performed within 24-48 hours when possible to reduce morbidity and mortality 2.

Surgical technique includes:

• Mobilization of fracture fragments 5
• Fixation with cannulated screws or tension band wiring 4, 5
• Repair of medial retinaculum if disrupted 5
• Consider leaving lateral retinaculum open to improve postoperative motion 5

For Minimally Displaced Fractures (intact extensor mechanism)

Nonoperative management is reasonable for patients with:

• Displacement <1 cm 6
• Intact extensor mechanism (ability to perform straight leg raise) 6, 7
• Medical comorbidities limiting surgical candidacy 6

Use a removable back splint for 1-2 weeks rather than a full plaster cylinder 7. Plaster cylinders lead to disuse osteoporosis and risk of refracture 7. Encourage early ambulation and knee flexion as soon as pain permits 6.

Important caveat: Nonoperative treatment of displaced fractures yields inferior results compared to operative treatment, with patients experiencing more activity restrictions and pain 6.

For Osteochondral Fractures

Open reduction and internal fixation of displaced osteochondral fragments is essential 4. These injuries require thorough evaluation with CT and MRI to exclude associated soft tissue injuries 4. Even isolated osteochondral fractures without ligament injury require surgical fixation for optimal outcomes 4.

Hematoma Management

Evacuate large or expanding hematomas surgically during fracture fixation 1. If the hematoma is causing compartment syndrome symptoms (severe pain, tense swelling, neurovascular compromise), immediate surgical decompression is required 1.

For smaller hematomas without compartment syndrome:

• Apply ice and compression initially 3
• Elevate the limb 3
• Monitor for expansion or signs of compartment syndrome 3

Postoperative/Conservative Management Protocol

• Weight-bearing: As tolerated with assistive device (crutches or walker) for first 2-3 weeks 3
• Do not prescribe complete bed rest—immobility increases complications 3
• Range of motion: Begin gentle exercises (hip flexion, abduction, adduction) after initial pain subsides, typically 3-5 days 3
• Progression: Advance to resistance exercises only after pain-free range of motion is achieved, typically 3-4 weeks 3
• Return to activity: Only after full pain-free function is restored, typically 6-8 weeks 3

Follow-Up and Monitoring

• Repeat evaluation at 1-2 weeks to confirm clinical improvement 3
• If pain or edema worsens or fails to improve by 2 weeks, obtain MRI 3
• New inability to bear weight requires urgent re-evaluation 3
• Follow-up radiographs to confirm fracture healing 4