What are the treatment options for a patient with a twisting left knee injury?

Treatment of Acute Twisting Left Knee Injury

For an acute twisting knee injury, immediately obtain anteroposterior and lateral radiographs as the mandatory first-line imaging, followed by conservative management with rest, ice, compression, elevation (RICE), NSAIDs for pain control, and early functional rehabilitation—reserving MRI for cases where radiographs are negative but clinical suspicion remains high for ligamentous or meniscal injury. 1

Immediate Evaluation and Imaging

Radiographs are mandatory as the first imaging study for any acute knee trauma with focal joint line tenderness, regardless of weight-bearing ability. 1

• Obtain minimum two views: anteroposterior and lateral (with knee flexed at 25-30 degrees) to evaluate for fractures and joint effusion 1
• The lateral view specifically allows detection of lipohemarthrosis, which indicates intra-articular fracture 1
• Do not defer imaging based on ability to bear weight alone—joint line tenderness is sufficient indication for radiographs 1

Initial Conservative Management

Begin RICE protocol (rest, ice, compression, elevation) for the first 24-72 hours after injury. 2

Pain Control

• NSAIDs are the first-line analgesic for acute knee injuries, providing effective pain relief and anti-inflammatory effects 3, 2
• Paracetamol (acetaminophen) is equally effective as NSAIDs for pain control if NSAIDs are contraindicated 3
• Avoid opioid analgesics due to significantly higher side effect profile without superior pain relief 3

Important caveat: NSAIDs may theoretically delay natural healing by suppressing inflammation necessary for tissue recovery, though clinical significance remains debated 3

Management Based on Radiographic Findings

If Radiographs Show Fracture

• Obtain orthopedic consultation for definitive fracture management 1
• Consider CT for better characterization of complex fractures, particularly tibial plateau or talar fractures 3, 1
• MRI may be indicated to assess for associated soft tissue injuries, bone marrow contusions, or risk of osteonecrosis (especially in talar fractures) 3, 4

If Radiographs Are Negative

Proceed with MRI without IV contrast as the most appropriate next imaging study to evaluate for occult fractures, meniscal tears, or ligamentous injuries. 4

• MRI is superior to CT for detecting bone marrow edema, occult fractures, meniscal tears, and ligament injuries 1
• The McMurray test (61% sensitivity, 84% specificity) and joint line tenderness (83% sensitivity, 83% specificity) help diagnose meniscal tears clinically 5

Specific Injury Management

Meniscal Tears

Conservative management with exercise therapy for 4-6 weeks is first-line treatment for most meniscal tears, including traumatic tears in patients under 40 years old. 5, 6

• Recent evidence shows acute traumatic meniscus tears in those younger than 40 can be successfully treated non-operatively with outcomes equal to surgery at 1 year 6
• Surgery is reserved only for severe traumatic bucket-handle tears with displaced meniscal tissue 5
• Degenerative meniscal tears should be treated with exercise therapy; surgery is not indicated even with mechanical symptoms 5

Ligamentous Injuries

Most acute knee ligament injuries, except grade III ACL tears, can be treated non-operatively, especially in the absence of concurrent injuries. 6

• MCL injuries: Grade III tears may require surgical repair only if unstable; most can be managed conservatively 4, 6
• ACL injuries: Complete tears typically require surgical reconstruction in younger, active patients 4
• PCL injuries: Surgical intervention needed only for multi-ligament injuries or persistent instability 4

Patellar Dislocation

Use short period of knee bracing in extension with progression to weight-bearing as tolerated. 6

Functional Rehabilitation Protocol

Begin functional support and exercise therapy immediately rather than immobilization, as this provides superior outcomes. 3

• Use ankle/knee brace for functional support for 4-6 weeks (extrapolating from ankle injury data, as knee-specific duration not specified in guidelines) 3
• If immobilization is used for severe pain/swelling, limit to maximum 10 days, then commence functional treatment 3
• Early exercise therapy reduces recurrent injury prevalence and improves functional outcomes 3
• Neuromuscular and proprioceptive exercises should be initiated early 3

Critical Pitfalls to Avoid

• Never skip radiographs in patients with joint line tenderness after twisting injury—physician judgment should only increase imaging indication, never decrease it 1
• Do not rely on weight-bearing ability alone to determine need for imaging 1
• Avoid prolonged immobilization beyond 10 days, as functional treatment produces better outcomes 3
• Do not assume all meniscal tears require surgery—conservative management is now first-line for most tears 5, 6
• Be vigilant for vascular injury in cases of knee dislocation or severe trauma; popliteal artery injuries require prompt surgical intervention 4