Management of Weber B Ankle Fractures
For stable Weber B ankle fractures (congruent mortise on radiographs with medial clear space <4mm), treatment with a walking boot, weight-bearing as tolerated, and urgent orthopedic referral is sufficient and safe. 1, 2
Initial Assessment of Stability
The critical decision point is determining fracture stability, which dictates whether non-operative management is appropriate:
- Obtain weight-bearing radiographs (AP, lateral, and mortise views) if the patient can tolerate them, as these provide the most important information about stability 1
- Measure the medial clear space: A distance <4mm confirms stability 1
- Look for signs of instability: medial tenderness, bruising or swelling, fibular fracture above the syndesmosis, bi- or trimalleolar involvement, or high-energy mechanism all increase likelihood of instability 1
Non-Operative Management Protocol for Stable Fractures
When the fracture is deemed stable based on the above criteria:
- Functional bracing with a walking boot is the preferred immobilization method 2
- Weight-bearing as tolerated immediately - patients can bear weight on the affected limb from the outset 2
- Urgent orthopedic referral (within 1-2 weeks) for specialist evaluation and confirmation of treatment plan 1
- No crutches are strictly necessary if the patient can ambulate comfortably, though they may be used for comfort initially 2
The evidence strongly supports this approach: a 2021 study of 123 patients with isolated stable Weber B fractures showed that functional bracing with early weight-bearing resulted in excellent outcomes, with all fractures progressing to union and no difference in functional scores compared to more restrictive treatment 2. This protocol also reduced the number of clinic visits and radiographs needed 2.
Evidence Supporting Non-Operative Management
Recent biomechanical research using weight-bearing CT demonstrates that congruent Weber B fractures do not alter tibiotalar contact mechanics compared to the uninjured side, with no significant differences in mean contact stress (2.10 MPa injured vs 2.10 MPa uninjured) or maximum contact stress 3. This provides the biomechanical rationale for why stable fractures can be safely managed non-operatively without risk of post-traumatic arthritis 3.
Current literature supports non-operative management of stable Weber B fractures, with surgical intervention reserved for unstable patterns 4. An ongoing randomized trial is even investigating whether unstable Weber B fractures might be managed non-operatively, though results are pending 5.
When Immediate Orthopedic Consultation is Required
Do not attempt outpatient management and obtain immediate orthopedic consultation for:
- Open fractures requiring wound management 6
- Neurovascular compromise or signs of vascular injury 6
- Obvious mortise widening (medial clear space >4mm) on initial radiographs 1
- Inability to obtain adequate radiographs to assess stability 1
- Bi- or trimalleolar fractures 1
Common Pitfalls to Avoid
- Failing to obtain weight-bearing views: Non-weight-bearing radiographs may miss instability that becomes apparent with loading 1
- Over-restricting activity: Prolonged immobilization and non-weight-bearing leads to stiffness, muscle atrophy, and poor functional outcomes 6
- Applying tight compression wraps: These can compromise circulation 6
- Manipulating the ankle before radiographs: This should be avoided unless there is neurovascular deficit or critical skin injury 1
Follow-Up Considerations
- Early range-of-motion exercises should begin within the first few days to prevent stiffness 6
- Repeat radiographs are only needed if clinical concern for displacement arises; routine post-immobilization films in stable fractures have minimal benefit 1
- Most patients can be discharged once radiographic and clinical union is confirmed, typically by 12-13 weeks 7