What is the recommended treatment for knee swelling after a crash with no open wound?

Management of Knee Swelling After Trauma Without Open Wound

Begin with plain radiographs (anteroposterior and lateral views) as the initial imaging study, especially if the patient has focal tenderness, joint effusion, or inability to bear weight. 1, 2

Initial Assessment and Imaging

Obtain knee radiographs immediately if any Ottawa knee rule criteria are present: 2

• Age >55 years
• Focal tenderness at the patella or fibular head
• Inability to bear weight for 4 steps immediately after injury
• Inability to flex knee to 90 degrees

Order radiographs regardless of Ottawa criteria if: 1, 2

• Gross deformity present
• Palpable mass
• Altered mental status (head injury, intoxication)
• Neuropathy
• History suggesting increased fracture risk

Minimum radiographic views should include: 2

• Anteroposterior view
• Lateral view (with knee at 25-30 degrees flexion)
• Consider patellofemoral view if patellar injury suspected 1

Immediate Management While Awaiting Imaging

Apply the RICE protocol (Rest, Ice, Compression, Elevation) immediately for all acute knee injuries with swelling. 3

Assess for vascular injury if significant trauma mechanism (motor vehicle accident, knee dislocation): 1

• Check for absent pulses, pallor, or neurological deficits
• These findings require immediate CTA of the lower extremity 1
• Vascular injury occurs in approximately 30% of posterior knee dislocations 1

Post-Radiograph Management Based on Findings

If Radiographs Show Fracture:

Proceed to orthopedic consultation for definitive management. 1

Consider CT without contrast for better fracture characterization, particularly for tibial plateau fractures. 1, 2

If Radiographs Are Negative:

The ability to bear weight after negative radiographs is a positive prognostic sign but does not rule out significant soft tissue injuries. 2

Order MRI without IV contrast if any of the following are present: 2, 4

• Significant joint effusion persisting beyond 5-7 days
• Inability to fully bear weight after 5-7 days
• Mechanical symptoms (locking, catching, giving way) suggesting meniscal injury
• Joint instability on examination suggesting ligamentous injury
• Persistent pain despite conservative management

MRI without contrast is superior for evaluating: 4

• Meniscal tears
• Ligamentous injuries (ACL, PCL, MCL, LCL)
• Bone marrow contusions and occult fractures
• Articular cartilage damage

Conservative Management Protocol

For patients with negative radiographs and ability to bear weight, initiate conservative management: 5, 6

Pain and swelling control: 1

• NSAIDs help reduce swelling and pain and may decrease time to return to usual activities 1
• Continue ice application
• Compression with elastic bandage or knee sleeve
• Elevation when possible

Functional support: 1

• Semirigid or lace-up ankle supports are recommended as functional treatment 1
• These devices decrease risk of recurrent injury, especially in patients with history of previous sprains 1

Early mobilization: 5, 6

• Maintain range of motion exercises
• Focus on quadriceps activation
• Progress weight-bearing as tolerated

Re-examination at 3-5 days post-injury is critical, as excessive swelling and pain can limit initial examination accuracy. 1

Indications for Specialist Referral

Refer to orthopedics if: 2, 5

• Joint instability on examination
• Inability to bear weight persisting beyond 5-7 days
• Mechanical symptoms (locking, catching)
• MRI reveals significant ligamentous injury (grade III ACL tear, LCL tear) or complex meniscal tear
• Persistent symptoms despite 4-6 weeks of conservative management

Important Clinical Pitfalls

Do not assume negative radiographs rule out significant injury—occult fractures and soft tissue injuries are common. 2, 7

In patients with femoral shaft fractures from high-energy trauma, ipsilateral knee ligament damage occurs in 48% of cases and is often missed initially. 7

Avoid ordering MRI with IV contrast for routine meniscal or ligamentous injuries—it provides no additional diagnostic value over non-contrast MRI. 4

Most MCL tears, PCL tears, and small meniscal injuries can be managed conservatively, while ACL tears, LCL tears, and large meniscal tears typically require surgical management. 5, 6