Initial Management: Plain Radiography
The most appropriate initial step in management is plain radiography of the left knee (anteroposterior and lateral views). 1
Clinical Reasoning
This patient presents with a non-contact twisting injury during soccer with:
- Ability to bear weight (though with difficulty)
- Medial femoral condyle tenderness
- Moderate edema
- Pain on extension testing
- Pain with turning in bed (suggesting mechanical symptoms)
These findings meet Ottawa knee rule criteria (focal tenderness and difficulty bearing weight), which mandates radiographic evaluation as the initial imaging study 1, 2.
Why Radiography First?
Radiographs must be obtained before any other intervention to exclude fracture, which occurs in approximately 5% of acute knee trauma cases presenting to emergency departments 2. The ACR Appropriateness Criteria (2020) explicitly states that with positive Ottawa rule criteria—including focal tenderness and/or inability to bear weight—radiographs should be the initial imaging modality 1.
Standard Views Required:
- Anteroposterior and lateral views (minimum two views)
- Lateral view obtained at 25-30 degrees of flexion to evaluate for joint effusion
- Consider cross-table lateral with horizontal beam to visualize lipohemarthrosis if intra-articular fracture suspected 1
Why Not the Other Options?
Steroid application would be premature and potentially harmful without excluding fracture or establishing a definitive diagnosis.
Physical therapy referral cannot proceed safely without first ruling out fracture. While PT is integral to knee injury management 3, it must follow appropriate diagnostic workup.
Next Steps After Radiography
If radiographs show no fracture but clinical suspicion remains high for internal derangement (meniscal tear, ligament injury):
- MRI becomes the next appropriate study 1, 4
- MRI is superior for evaluating meniscal tears, cruciate ligament injuries, and cartilage damage 4
- The medial femoral condyle tenderness and mechanical symptoms (pain with turning, extension pain) suggest possible meniscal pathology 5
Common Pitfall to Avoid:
Do not skip radiography and proceed directly to MRI or treatment, even when soft tissue injury seems obvious. Fractures can be missed clinically, and the Ottawa rules exist specifically to prevent this error while avoiding unnecessary imaging in truly low-risk patients 1, 2.