What is the treatment for an acute vertical fracture of the patella with hemarthrosis?

Treatment of Acute Vertical Patellar Fracture with Hemarthrosis

For an acute vertical patellar fracture with hemarthrosis, immediate surgical fixation with modified tension band wiring (using two parallel K-wires orthogonal to the fracture line with cerclage wire) is the treatment of choice, provided the patient is hemodynamically stable and has an intact extensor mechanism. 1

Initial Assessment and Imaging

Radiographic Evaluation

• Obtain anteroposterior and lateral knee radiographs as the initial imaging study, with an additional patellofemoral (sunrise) view specifically to evaluate the patellar fracture 2
• These views are essential for any patient with focal patellar tenderness and joint effusion (hemarthrosis) meeting Ottawa rule criteria 2

Critical Clinical Examination

• Verify extensor mechanism integrity: The patient must demonstrate active knee extension against gravity with no extension lag 3
• Assess for displacement: Fracture fragments should be evaluated for gap and articular step-off 3
• Evaluate hemodynamic stability and rule out compartment syndrome or vascular compromise 3

Treatment Algorithm Based on Fracture Characteristics

For Displaced Vertical Fractures (Most Common Scenario)

Surgical fixation is indicated when:

• Fracture displacement exceeds 2-3mm 3
• Any articular step-off is present 3
• Extensor mechanism is disrupted (inability to actively extend knee) 3

Surgical Technique

• Modified tension band wiring is the preferred method for vertical fractures, consisting of two parallel K-wires positioned orthogonal to the fracture line with cerclage wire shaped anteriorly as a figure-of-eight 1
• For open fractures (Gustilo-Anderson type IIIA), early surgical fixation within 24 hours benefits infection prevention and provides earlier joint motion 1
• Additional circular cerclage wiring using metal or FiberWire increases fixation stability and decreases re-dislocation risk 4

Timing of Surgery

• In hemodynamically stable patients without severe visceral injuries: Perform early definitive osteosynthesis within the first 24 hours to reduce local and systemic complications 2
• In patients with circulatory shock, respiratory failure, or severe associated injuries: Delay definitive osteosynthesis and consider temporary stabilization first 2
• The "PRompt Individualised Safe Management" (PRISM) approach prioritizes physiologic stability over immediate fracture fixation 5

For Minimally Displaced Fractures (<2-3mm, Intact Extensor Mechanism)

Conservative management may be considered when ALL criteria are met:

• Displacement less than 2-3mm 3
• No articular step-off 3
• Intact extensor mechanism with active knee extension 3
• Patient can comply with immobilization and weight-bearing restrictions 3

Conservative Protocol

• Immobilize knee in full extension using a knee immobilizer worn at all times except for hygiene 3
• Non-weight bearing or touch-down weight bearing with crutches initially 3
• First follow-up within 5-7 days to reassess extensor mechanism and check for displacement progression 3
• Serial radiographs at 1-2 week intervals for the first 3-4 weeks to monitor for late displacement 3

Hemarthrosis Management

• Aspiration of hemarthrosis may be performed for patient comfort and to facilitate clinical examination, but is not mandatory 6
• The presence of hemarthrosis itself does not change the treatment algorithm—management is determined by fracture displacement and extensor mechanism integrity 3

Perioperative Considerations

Antibiotic Prophylaxis

• For open fractures, initiate antibiotic prophylaxis immediately according to surgical antibiotic prophylaxis guidelines 2
• Check tetanus immunization status and provide prophylaxis as needed 2

Thromboprophylaxis

• Initiate early pharmacological thromboprophylaxis with low molecular weight heparin (LMWH) after hemorrhage control and hemostasis, particularly for lower extremity immobilization 2, 3
• Timing should be within 6 hours following trauma or surgery for isolated lower limb trauma without persisting bleeding 2

Rehabilitation

• Early rehabilitation is crucial regardless of treatment method to avoid knee joint capsule contractures and cartilage degeneration 4
• Precocious articular mobilization improves prognosis and should be adopted whenever possible 1
• Expected outcomes: Full extension and 120° of knee flexion by 12 months postoperatively 1

Critical Pitfalls to Avoid

• Do not rush surgical intervention in hemodynamically unstable patients: The "second hit" phenomenon from premature surgery in unstable patients increases morbidity and mortality 5
• Do not rely on clinical decision rules in special populations: Ottawa/Pittsburgh rules do not apply to patients with diabetes, paraplegia, or altered mental status—these patients require radiographs regardless of clinical findings 2, 3
• Do not miss associated injuries: In the setting of hemarthrosis from trauma, consider MRI if internal derangement (meniscal or ligamentous injury) is suspected after initial stabilization 2
• Avoid delayed diagnosis of displacement: Serial radiographic follow-up is essential in conservatively managed fractures, as late displacement can occur 3