What is the appropriate management for an 8-year-old male with sudden onset right patellar pain after a traumatic collision at a trampoline park, exacerbated by movement and weight-bearing?

Management of Acute Traumatic Patellar Pain in an 8-Year-Old

Obtain knee radiographs immediately (anteroposterior and lateral views minimum) to rule out patellar fracture or dislocation, as this 8-year-old meets criteria for imaging based on inability to walk comfortably and acute traumatic mechanism. 1

Initial Imaging Decision

This child requires radiographs based on validated clinical decision rules:

• The Ottawa Knee Rule and Pittsburgh Decision Rule both indicate radiography for children under 12 years old with acute knee trauma 1
• The Pittsburgh Rule specifically mandates radiographs for patients <12 years old or >50 years old, regardless of other findings 1
• This child's inability to walk comfortably (pain worsens with movement and trying to walk) further supports imaging, as inability to take four weight-bearing steps is a key criterion 1

Standard knee radiographs should include minimum two views (anteroposterior and lateral), with the lateral obtained at 25-30 degrees of flexion 1. A patellofemoral view should be added if patellar fracture or dislocation is suspected based on mechanism and examination 1.

Key Examination Findings to Document

Before imaging, assess for:

• Point tenderness over the patella itself versus surrounding structures (helps differentiate patellar fracture from soft tissue injury) 1
• Palpable effusion or hemarthrosis (suggests intra-articular injury including fracture) 1
• Ability to perform straight leg raise (inability suggests extensor mechanism disruption) 1
• Gross deformity or palpable defect (indicates displaced fracture or complete tendon rupture requiring urgent orthopedic consultation) 1

Trampoline-Specific Injury Patterns

This mechanism warrants heightened concern:

• Children 6 years and younger are at particularly high risk for proximal tibial fractures from trampoline injuries, especially when colliding with larger individuals 1
• While this child is 8 years old, the collision mechanism with another child creates similar high-impact forces 1
• Lower extremity injuries account for 34-50% of trampoline injuries, with approximately 60% involving fractures in upper extremity injuries 1

Management Algorithm Based on Radiograph Results

If Radiographs Show Patellar Fracture:

• Displaced fractures (>2-3mm articular step-off or extensor mechanism disruption) require urgent orthopedic referral for surgical fixation 1
• Non-displaced fractures can be managed with cylinder cast or knee immobilizer in full extension for 4-6 weeks 1
• Serial radiographs at 1-2 weeks to confirm no displacement 1

If Radiographs Show Patellar Dislocation (Reduced or Unreduced):

• Acute dislocation requires immobilization in extension and orthopedic follow-up within 1 week 1
• First-time dislocations in children have high recurrence rates and may require surgical stabilization 1

If Radiographs Are Negative:

Proceed with MRI without IV contrast if:

• Pain persists beyond 1 week despite conservative management 1
• Clinical suspicion for osteochondral injury (mechanism suggests impaction force) 1
• Concern for patellar tendon or quadriceps tendon injury (inability to perform straight leg raise) 1

Initial conservative management includes:

• Knee immobilizer or hinged brace for comfort and protection 1
• Non-weight-bearing or protected weight-bearing with crutches until pain improves 1
• NSAIDs for pain control 2
• Ice application 15-20 minutes every 2-3 hours for first 48-72 hours 2

Critical Pitfalls to Avoid

• Do not rely on clinical examination alone in the first 48 hours, as swelling and pain limit accurate assessment 2
• Do not miss associated injuries: trampoline collisions can cause multiple injuries including head/neck trauma (10-17% of trampoline injuries involve head/neck) 1
• Do not discharge without clear return precautions: any neck pain, torticollis, or neurologic symptoms require immediate re-evaluation for potential cervical spine injury 1
• Do not apply Ottawa Ankle Rules to this knee injury - the provided evidence about ankle rules 1 is not applicable to this patellar injury 1

Follow-Up Timing

• Re-evaluate in 3-5 days if managed conservatively to reassess pain, swelling, and function when acute inflammation has subsided 2
• Immediate orthopedic referral if: unable to perform straight leg raise, gross deformity, displaced fracture on radiographs, or unreduced dislocation 1