Management of Severe Persistent Knee Pain in a Young Athlete Following Traumatic Injury
This 18-year-old athlete with severe, persistent knee pain two weeks post-injury requires immediate knee radiographs followed by MRI if radiographs are negative, given the inability to bear weight and severity of symptoms suggesting possible internal derangement or occult fracture. 1
Immediate Diagnostic Approach
Initial Imaging: Knee Radiographs
Knee radiographs are usually appropriate as the initial imaging study given this patient meets multiple criteria from the ACR Appropriateness Criteria: 1
- Focal tenderness (posterior/popliteal area)
- Inability to bear weight ("barely put pressure" on knee, difficulty walking)
- Severe persistent pain at 2 weeks post-injury
The patient clearly meets Ottawa Knee Rule criteria, which would mandate radiography in anyone ≥18 years with inability to bear weight immediately after injury or inability to take four steps in the emergency department. 1
Critical Red Flag: Popliteal Pain Location
The posterior/popliteal location of worst pain is particularly concerning and requires careful evaluation for: 1
- Vascular injury (popliteal artery damage from knee dislocation or severe ligamentous injury)
- Posterior cruciate ligament (PCL) injury
- Meniscal tear with posterior horn involvement
If there are any signs of vascular compromise (diminished pulses, pallor, neurological deficits), this becomes a surgical emergency requiring immediate vascular imaging with CTA. 1
Advanced Imaging Algorithm
When Radiographs Are Negative
MRI knee without IV contrast is usually appropriate as the next imaging study after negative radiographs in this young adult with suspected internal derangement. 1 This should be obtained without delay given:
- Persistent severe pain at 2 weeks
- Functional disability (cannot bear weight)
- High suspicion for soft tissue injury (meniscus, ligaments, cartilage)
Do not wait beyond 2-3 weeks with negative radiographs before proceeding to MRI in a patient with this severity of symptoms. 2 The evidence shows that early MRI (rather than prolonged conservative management) is appropriate when functional disability persists. 3, 4
What MRI Will Evaluate
MRI is highly sensitive for: 1
- Meniscal tears (particularly concerning given traumatic mechanism in young athlete)
- Ligamentous injuries (ACL, PCL, MCL, LCL)
- Occult fractures not visible on radiographs
- Osteochondral injuries
- Bone contusions
Initial Management While Awaiting Imaging
Pain Control
NSAIDs should be initiated immediately for both pain control and anti-inflammatory effects, despite the patient's preference to avoid medications. 1, 3 The severity of pain ("paralyzing," inability to bear weight) justifies pharmacological intervention. The patient's concern about taste can be addressed with:
- Liquid formulations with flavoring
- Enteric-coated tablets
- Alternative routes if oral truly not tolerated
Mechanical Support
Continue knee bracing as the patient reports this provides relief. 4 For severe injuries with inability to bear weight:
- Hinged knee brace for stability
- Crutches for non-weight bearing or touch-down weight bearing until diagnosis is established 4
Activity Modification
Strict activity modification is essential: 3, 5
- No sports participation until diagnosis established
- Avoid stairs, squatting, pivoting
- Ice application 15-20 minutes every 2-3 hours
- Elevation when resting
Common Pitfalls to Avoid
Do Not Delay Imaging
The most critical error would be prolonged conservative management without establishing a diagnosis in a patient with this severity of symptoms. 6 Research shows that chronic traumatic anterior knee pain that persists beyond 2 years rarely improves, with 68% having moderate-to-severe pain at long-term follow-up. 6
Do Not Miss Vascular Injury
With posterior/popliteal pain, always assess vascular status: 1
- Palpate dorsalis pedis and posterior tibial pulses
- Compare to contralateral side
- Check capillary refill
- Assess for any neurological deficits
If pulses are diminished or absent, this requires immediate CTA of the lower extremity as knee dislocations (even if spontaneously reduced) can cause popliteal artery injury. 1
Do Not Assume Overuse Tendinopathy
The evidence on patellar tendinopathy 1 is not applicable to this case—this is an acute traumatic injury with severe functional impairment, not an overuse condition. The mechanism (collision/fall), severity, and inability to bear weight suggest internal derangement rather than tendinopathy.
Definitive Management Based on Imaging Results
If Meniscal Tear Identified
For traumatic meniscal tears in patients <40 years: 3, 4
- Conservative management first (exercise therapy for 4-6 weeks) is appropriate for most tears
- Surgical referral indicated for: 3
- Bucket-handle tears with displaced tissue
- Locked knee (true mechanical block to extension)
- Failure of 4-6 weeks conservative management with persistent functional disability
If Ligamentous Injury Identified
Most acute knee ligament injuries can be treated non-operatively except grade III ACL tears with concurrent injuries. 4 Management includes:
- Structured rehabilitation program
- Progressive weight-bearing
- Bracing during healing phase
If Occult Fracture Identified
Management depends on fracture type and stability: 1
- Stable fractures: immobilization and radiographic follow-up
- Unstable fractures: orthopedic referral for potential surgical fixation
Timeline for Specialist Referral
Orthopedic referral is indicated if: 2, 5
- Immediate: Vascular compromise, locked knee, displaced fracture
- Urgent (within 1 week): Inability to bear weight persisting beyond initial evaluation with imaging
- Elective (6-8 weeks): Symptoms persist despite appropriate conservative management
This patient's severity of symptoms (inability to bear weight at 2 weeks) warrants expedited orthopedic evaluation once imaging is complete, rather than prolonged conservative management. 5, 4