What is an appropriate plan of care for a 35-year-old woman with right calf and knee pain after blunt-force trauma?

Plan of Care for 35-Year-Old Female with Right Calf and Knee Pain After Blunt Force Trauma

Obtain anteroposterior and lateral knee radiographs immediately as the first-line imaging study, since this patient has focal joint line tenderness after acute trauma, regardless of her ability to bear weight. 1, 2

Immediate Assessment and Imaging

Initial Clinical Evaluation

• Check for vascular compromise immediately: assess for absent pulses, pallor, cool extremity, or delayed capillary refill in the affected leg, as popliteal artery injury occurs in up to 30% of severe knee trauma and constitutes a limb-threatening emergency 1, 3
• Perform neurological examination: test for peroneal and tibial nerve injuries by assessing motor function (dorsiflexion, plantarflexion) and sensation in the lower leg and foot 3
• Measure ankle-brachial index (ABI): if vascular injury is suspected, an ABI <0.9 has 87% sensitivity and 97% specificity for diagnosing vascular injury 1

Mandatory Initial Imaging

• Obtain minimum two-view radiographs (anteroposterior and lateral with knee at 25-30 degrees flexion) as the first imaging study 1, 2
• The lateral view allows evaluation for joint effusion and lipohemarthrosis, which frequently indicates intra-articular fracture 2
• Apply Ottawa Knee Rule criteria: this 35-year-old patient requires radiographs if she has palpable fibular head tenderness, isolated patellar tenderness, cannot flex knee to 90°, or cannot bear weight for 4 steps 1

Advanced Imaging Based on Initial Findings

• Order CT angiography (CTA) immediately if any signs of vascular compromise are present (weak or absent pulses, expanding hematoma, neurological deficit suggesting nerve compression), as CTA is less invasive than conventional angiography with comparable accuracy for detecting popliteal artery injuries 1, 3
• Obtain non-contrast MRI after plain radiographs to evaluate multiligamentous injury, meniscal tears, and occult fractures, as MRI is the gold standard for soft-tissue evaluation with 87% sensitivity for meniscal tears and 74% sensitivity for ACL injuries 3, 2, 4, 5
• Consider non-contrast CT for better characterization of complex fractures if tibial plateau or other fractures are identified on radiographs, as CT shows 100% sensitivity versus 83% for radiographs alone 2

Pain Management Protocol

First-Line Multimodal Analgesia

• Administer acetaminophen 1000 mg IV or PO every 6 hours (maximum 4 g per 24 hours) as the cornerstone of analgesia 1, 6
• Apply topical lidocaine patches directly over the painful calf to achieve localized analgesia without systemic exposure 6
• Employ non-pharmacologic measures: elevate the leg and apply intermittent ice packs to reduce swelling and discomfort 1, 6

Additional Analgesic Considerations

• Add NSAIDs only for severe pain after careful assessment of cardiovascular disease, renal function, and bleeding risk, and co-prescribe a proton pump inhibitor if NSAIDs are used 1, 6
• Reserve opioid agents (e.g., oxycodone 5-15 mg PO every 4-6 hours) strictly for breakthrough pain unresponsive to acetaminophen and NSAIDs, using the lowest effective dose for the shortest possible duration 1, 7
• Perform routine pain intensity assessments, recognizing that approximately 42% of patients receive inadequate analgesia despite reporting moderate-to-high pain levels 6

Venous Thromboembolism Prophylaxis

• Initiate low-molecular-weight heparin (LMWH) or unfractionated heparin (UFH) as soon as possible in this moderate-to-high-risk trauma patient, adjusted according to renal function, weight, and bleeding risk 1
• If deep vein thrombosis is objectively confirmed by ultrasound, begin immediate therapeutic anticoagulation and continue for at least 3 months for trauma-associated DVT 6

Antibiotic Considerations

• Do not administer prophylactic antibiotics in this blunt trauma patient in the absence of open wounds, signs of sepsis, or septic shock 1
• Antibiotics are indicated only for penetrating trauma, open fractures, or severe burns to decrease septic complications 1

Disposition and Follow-Up

If Radiographs Show Fracture

• Obtain orthopedic consultation for definitive management of any identified fractures 2
• Tibial plateau fractures may require surgical fixation depending on displacement and stability 2
• Non-displaced fractures may be managed conservatively with protected weight-bearing and close follow-up 2

If Ligamentous or Meniscal Injury Suspected

• Arrange expedited follow-up with orthopedic specialist for consideration of MRI and further management within 1-2 weeks 8
• Physical examination findings guide urgency: joint line tenderness is 83% sensitive and 83% specific for meniscal tears; the McMurray test is 97% specific but only 52% sensitive 1, 5
• The Lachman test is more sensitive and specific for ACL tears than the anterior drawer sign 5

If Vascular Injury Confirmed

• Prepare for urgent surgical intervention immediately, as arterial injuries must be repaired first to preserve limb viability 3
• Time to revascularization is critical for limb salvage; do not delay vascular imaging if any concern exists 3

Critical Pitfalls to Avoid

• Do not defer imaging based on ability to bear weight alone, as joint line tenderness after trauma is sufficient indication for radiographs regardless of weight-bearing status 1, 2
• Do not miss vascular injury: popliteal artery disruption occurs in 7.5-30% of severe knee trauma cases and requires prompt imaging and intervention 3
• Do not order MRI as the initial imaging study; plain radiographs must precede MRI in acute knee trauma evaluation 3, 2
• Do not use MRI with IV contrast for routine evaluation; non-contrast MRI is sufficient and appropriate 3
• Avoid excessive opioid use, as elderly and trauma patients are particularly vulnerable to opioid accumulation, respiratory depression, and delirium 1