Knee Trauma Management

Initial Evaluation

The American College of Radiology recommends radiographs as the first-line imaging for knee trauma and pain evaluation, particularly when focal tenderness, effusion, or inability to bear weight is present 1
Radiographs for bilateral small joint effusion should include at least one frontal projection of both knees, a tangential patellar view, and lateral views, according to the American College of Radiology 2

When radiographs are negative but clinical suspicion remains high for internal derangement, MRI of the knee without IV contrast is usually appropriate as the next imaging study 1
MRI of the knee without IV contrast is also appropriate for suspected occult fractures not visible on radiographs 1

The American College of Radiology recommends the following imaging modalities:

Imaging Modality	Indication
Radiographs (X-rays)	Initial assessment, rule out fractures
MRI without contrast	Second-line imaging, internal derangement suspected, clinical instability present
CT without contrast	Suspected radiographically occult fractures and evaluation of bony structures

MRI is preferred when soft tissue injuries are the primary concern, ligamentous or meniscal damage is suspected, or bone marrow contusions need evaluation, with near 100% sensitivity for fracture detection and excellent for detecting bone marrow contusions, occult fractures, and soft tissue injuries, according to the American College of Radiology 1, 3
CT is a reasonable alternative to MRI when contraindicated or unavailable, with superior sensitivity to radiographs (80-100% sensitivity for fractures) and excellent for bony detail and fracture characterization, but with limitations including ionizing radiation exposure and less sensitivity than MRI for soft tissue injuries, as stated by the American College of Radiology 1, 4

After tibial plateau fracture diagnosis, MRI is recommended to evaluate additional bone or soft tissue injury 1
Following knee dislocation, MRI is recommended to assess soft tissue, osseous, and neural injuries 1
The primary treatment priority for knee dislocation is immediate reduction and stabilization, followed by thorough vascular assessment to prevent limb-threatening complications, as recommended by the American Society of Anesthesiologists 5
Vascular repair must be performed within 6-8 hours to prevent irreversible ischemic damage 5
Immediate surgical exploration of the popliteal artery is required if pulses are abnormal or absent after reduction, as recommended by the American College of Radiology 5

In cases of knee dislocation, MRA may be performed simultaneously with MRI to evaluate vascular injuries with less morbidity compared to conventional angiography 1
Vascular compromise requiring amputation can occur if arterial repair is delayed >8 hours, with a reported rate of up to 86% 5

Exercise therapy, including joint-specific strengthening exercises, general aerobic conditioning, and hip and knee strengthening, is strongly recommended for most knee conditions, according to the American College of Radiology, the European League Against Rheumatism, and the British Journal of Sports Medicine 1, 6, 7
Weight management is recommended if the patient is overweight, to reduce knee load, with a strength of evidence rated as moderate, as suggested by the American Academy of Family Physicians and the European League Against Rheumatism 8, 9, 6
Rest and activity modification can prevent ongoing damage while avoiding complete immobilization, and patients should continue activities that don't worsen pain, as recommended by the American Academy of Family Physicians 10
Cryotherapy, such as applying ice through a wet towel for 10-minute periods, is effective for short-term pain relief and reducing swelling, and blunts inflammatory response in acute cases, according to the American Academy of Family Physicians 10
Acetaminophen should be considered as first-line medication, with NSAIDs (oral or topical) as second-line if acetaminophen is insufficient, as recommended by the American Academy of Family Physicians and the American Academy of Orthopaedic Surgeons 11, 9

Orthopedic referral is recommended when conservative management fails after 6-8 weeks of optimized treatment, persistent mechanical symptoms are present, progressive instability occurs despite rehabilitation, or MRI reveals pathology requiring surgical intervention, as recommended by the British Medical Journal 2
The BMJ clinical practice guideline (2017) makes a strong recommendation against arthroscopy for degenerative knee disease, including meniscal tears, based on high-quality evidence showing that arthroscopic surgery provides no meaningful benefit over conservative management for pain, function, or quality of life 12
Surgery should only be considered in specific circumstances, such as persistent mechanical symptoms after 6-8 weeks of optimized conservative treatment, progressive instability despite rehabilitation, MRI reveals pathology requiring surgical intervention, or true locked knee (objective inability to fully extend the knee), as recommended by the BMJ clinical practice guideline (2017) 12
Potential complications include arthrofibrosis, venous thromboembolism, compartment syndrome, and heterotopic ossification, as reported by the American Academy of Orthopaedic Surgeons 13
Peroneal nerve injury can occur, often requiring ankle-foot orthosis, as reported by the American Academy of Orthopaedic Surgeons 13