What is the treatment for a displaced patella (kneecap) with a hematoma near the patella?

Treatment for Displaced Patella with Hematoma

Immediately immobilize the knee in full extension, obtain standard radiographs (AP, lateral, and patellofemoral views) to assess for fracture versus dislocation, and arrange urgent orthopedic consultation for definitive management. 1

Immediate Assessment and Stabilization

The presence of a displaced kneecap with hematoma requires urgent evaluation to distinguish between:

• Patellar fracture (broken kneecap requiring surgical fixation in most displaced cases)
• Patellar dislocation (kneecap out of joint, may reduce spontaneously or require manual reduction)

Critical Clinical Indicators

Key findings that suggest patellar fracture include: 1

• Inability to perform straight leg raise against gravity
• Palpable defect in the patella
• Severe focal patellar tenderness
• Large knee effusion/hemarthrosis (the hematoma you're seeing)
• Inability to bear weight

Immediate Management Steps

1. Immobilize the knee in full extension using a knee immobilizer or posterior splint 1

2. Maintain non-weight-bearing status until fracture is excluded or surgical consultation obtained 1

3. Obtain imaging urgently: Standard radiographs with AP, lateral, and patellofemoral views are mandatory as the initial study 1, 2

Definitive Treatment Based on Diagnosis

If Patellar Fracture is Confirmed:

Displaced patellar fractures (>1cm displacement or disrupted extensor mechanism) typically require surgical fixation to restore function and prevent long-term disability. 3

• Surgical options include tension band wiring for simple displaced fractures, partial patellectomy if comminution prevents adequate fixation but 3/5 of patella can be preserved, or rarely total patellectomy for severe comminution 3

• Nonoperative treatment with immobilization is only reasonable for patients with severe medical comorbidities limiting activity, though operative treatment yields better functional outcomes 4

If Patellar Dislocation is Confirmed:

Reduction should be performed as soon as possible for pain relief and to prevent neurovascular complications. 5

• Prehospital reduction by trained providers has a 92% success rate with minimal complications and reduces median pain scores from 10 to 2 5

• After reduction (spontaneous or manual), immobilize and obtain post-reduction radiographs to assess for osteochondral injury 2

Common Pitfalls to Avoid

• Do NOT assume this is just a "bruise" - a hematoma near a displaced patella indicates significant injury requiring imaging 1

• Do NOT delay imaging - obtain radiographs first before any advanced imaging like MRI 1

• Do NOT use prolonged rigid immobilization for minimally displaced fractures, as this can lead to disuse osteoporosis and refracture; consider removable splinting for 1-2 weeks instead 6

• Do NOT miss concomitant injuries - obtain cross-table lateral view to look for lipohemarthrosis indicating intra-articular fracture 1

Follow-up Imaging if Initial Radiographs Are Negative

If clinical suspicion remains high despite normal radiographs (persistent inability to bear weight, large effusion, inability to straight leg raise), MRI without contrast is the next appropriate study to evaluate for occult fracture or soft tissue injury. 1