In the webinar below, Dr Joe Kang (radiology registrar) provides a structured approach to interpreting knee, ankle & foot x-rays, with an overview of common cases & pitfalls.
Contents
Our Webinar

Key Points
- Two Views to Exclude a Fracture: Always obtain two views to accurately exclude a fracture.
- Bone Alignment: Check the alignment of bones for any dislocation or misalignment.
- Cortex Examination: Examine the cortex for disruptions, steps, or abnormalities.
- Soft Tissue Observation: Look for signs of swelling or effusion indicating underlying fractures.
Knee X-Ray Views
- AP View (Anterior-Posterior):Â Standard front-to-back view.
- Horizontal Beam Lateral (HBL) View:Â Essential for detecting knee effusions, look for fat-fluid levels indicating lipohemarthrosis.
- Skyline View:Â Useful for identifying patellar fractures and joint alignment.
Fracture Examples in the Knee
- Tibial Plateau Fracture:
- Look for cortical disruption and changes in trabecular pattern.
- Presence of lipohemarthrosis (fat-fluid level) indicates intra-articular fracture.
- Patellar Fracture:
- Typically more apparent on a skyline view.
- Look for cortical discontinuity and alignment issues.
- Fibular Head Fracture:
- Often associated with tibial fractures, indicating high-energy trauma.
Ankle X-Ray Views
AP and Lateral Views:Â Standard views for assessing ankle injuries.
- Weber Classification:
- Type A:Â Below the syndesmosis, often managed conservatively.
- Type B:Â At the level of the syndesmosis, may require surgery.
- Type C:Â Above the syndesmosis, usually unstable and requires surgical intervention.
Complex Fractures in the Ankle
- Maisonneuve Fracture:
- Proximal fibular fracture with associated ankle injury.
- Requires imaging of both the knee and ankle.
- Look for widening of the ankle mortise indicating ligamentous injury.
- Polo Mint Principle:
- A ring structure (tibia and fibula) typically breaks in two places.
- If one fracture is identified, look for the second.
Foot X-Ray Views
AP, Oblique, and Lateral Views:Â Standard views for foot injuries. Ensure proper alignment of the bones.
Fracture Examples in the Foot
- Stress Fractures:
- Look for periosteal reaction and subtle lucencies.
- Commonly affects the third and fourth metatarsals, often due to overuse.
- Lisfranc Injury:
- Disruption of the alignment in the midfoot.
- On AP view, check alignment of the first metatarsal with the medial cuneiform.
- On oblique view, check alignment of the second metatarsal with the middle cuneiform.
- Widening of the joint spaces in the midfoot indicates instability.
- Calcaneal Fracture:
- Typically results from a fall landing on the feet.
- Look for comminuted fractures and flattening of Böhler’s angle.
- Bilateral calcaneal fractures suggest high-energy trauma; assess for spine and pelvis injuries.
- Base of Fifth Metatarsal Fracture:
- Commonly due to inversion injuries.
- Check for avulsion fractures at the insertion of the peroneus brevis tendon.
- Osteomyelitis:
- Look for bone destruction and periosteal reaction.
- Associated with soft tissue ulcers and infections, common in diabetic patients.
- Follow-up films or MRI may be necessary for early detection.
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