Ankle Fracture (Weber Classification)
Classification systems
- AO/OTA alphanumeric grouping for the malleolar segment
- Descriptive: unimalleolar, bimalleolar, trimalleolar, with or without syndesmotic injury
Mechanism
A rotational injury to the loaded ankle — typically a twist while the foot is planted, going over on uneven ground, on stairs, or in sport. The foot's position at the moment of injury (supinated or pronated) and the direction of the rotational force determine the sequence in which the lateral structures, medial structures and syndesmosis fail, which is exactly what the mechanism-based classification encodes. Direct axial loading from a height produces a pilon-type injury instead, which is a different problem.
Age considerations
- Paediatric
- The distal tibial physis fails before the ligaments, producing transitional injuries in the closing physis, so plain films can look deceptively benign; a low threshold for cross-sectional imaging to assess articular step is appropriate. Growth arrest and angular deformity are the specific late risks.
- Young adult
- Usually the sporting or road traffic twist. The articular surface tolerates malreduction poorly and post-traumatic arthritis follows imperfect restoration of fibular length and rotation, so anatomical fixation and early functional rehabilitation are the priorities.
- Elderly
- Osteoporotic bone, thin fragile soft tissues and diabetes change the calculus. Wound breakdown and fixation failure are real risks; augmented constructs, longer immobilisation, and in selected frail patients a considered non-operative or minimal-fixation plan may serve better than an ideal radiograph.
Management options
Non-operative functional treatment in a cast or bootshowhide
Indication
Stable isolated fractures at or below the syndesmosis with an intact medial side and a congruent mortise, and selected frail patients where surgical risk outweighs radiographic benefit.
Implant design notes
No implant. A below-knee cast or a removable walker boot maintaining the ankle at neutral; the boot permits earlier controlled motion and hygiene.
Approach
Non-operative, with serial radiographic surveillance to confirm the mortise stays congruent.
Steps overview
- Assess medial-sided tenderness and swelling as a marker of deep deltoid involvement
- Obtain adequate views including a mortise view; consider a stress or weight-bearing view for equivocal stability
- Apply a below-knee cast or boot with the ankle at neutral, never in equinus
- Repeat radiographs at one and two weeks to confirm the mortise remains congruent
- Progress weight bearing according to stability and comfort
- Start range of motion and proprioceptive rehabilitation once out of immobilisation
Notes
Late medial clear-space widening on follow-up films is the trap — it converts a 'stable' injury into an unstable one requiring fixation.
Resident summary compiled from standard orthopaedic trauma teaching; verify against your departmental protocol.
Open reduction and internal fixation of the fibulashowhide
Indication
Unstable patterns, talar shift, displaced fibular fractures at or above the syndesmosis, and bimalleolar or trimalleolar injuries.
Implant design notes
One-third tubular or small-fragment plate applied laterally as a neutralisation plate over a lag screw, or posteriorly as an antiglide plate which is biomechanically favourable in oblique patterns and puts the implant away from the thin lateral skin. Locking constructs and intramedullary fibular nails have a role in osteoporotic bone and poor soft tissue.
Approach
Direct lateral or posterolateral approach to the fibula, protecting the superficial peroneal nerve proximally and the sural nerve posteriorly; medial approach as needed for the medial malleolus.
Steps overview
- Wait for soft tissue conditions to allow safe incision — assess wrinkle sign and blister status
- Supine with a sandbag under the ipsilateral buttock; tourniquet and image intensifier
- Lateral incision over the fibula, protecting the superficial peroneal nerve
- Expose the fracture, clear interposed periosteum and haematoma, and reduce for length and rotation
- Hold with a reduction clamp; place a lag screw across the oblique fracture where the pattern allows
- Apply the plate as a neutralisation or antiglide construct with adequate screws on each side
- Fix the medial malleolus with partially threaded screws or a tension band as required
- Assess syndesmotic stability under fluoroscopy and address it if unstable
- Confirm restored fibular length, talar position and a symmetrical mortise before closure
Notes
Fibular length and rotation govern the outcome; use the talocrural angle and the continuity of the subchondral line as intraoperative checks. Wound problems dominate the complication list in diabetics and smokers.
Resident summary compiled from standard orthopaedic trauma teaching; verify against your departmental protocol.
Syndesmotic stabilisationshowhide
Indication
Demonstrated syndesmotic instability, typically with a fibular fracture above the syndesmosis or a high fibular injury with medial-sided disruption.
Implant design notes
Trans-syndesmotic screws engaging three or four cortices, or a suture-button device that permits physiological micromotion and generally avoids a second procedure for removal. Both are placed parallel to the tibiotalar joint line and angled slightly anteriorly from posterolateral to anteromedial.
Approach
Through or adjacent to the lateral incision, with the ankle held reduced in the mortise.
Steps overview
- Fix the fibula to correct length and rotation first — the syndesmosis cannot be reduced onto a malreduced fibula
- Test stability with a lateral hook test and an external rotation stress view
- Reduce the fibula into the incisura anatomically, verifying on a true lateral and, where available, cross-sectional imaging
- Place the device parallel to the joint line, angled from posterolateral to anteromedial
- Recheck reduction after fixation; malreduction here is the strongest predictor of poor outcome
- Plan weight-bearing progression and discuss whether removal will be needed
Notes
Malreduction of the fibula within the incisura is the classic exam and clinical pitfall — a screw does not correct a bad reduction, it fixes it in place.
Resident summary compiled from standard orthopaedic trauma teaching; verify against your departmental protocol.
Viva pearls
- State the principle behind Weber clearly: the higher the fibular fracture relative to the syndesmosis, the greater the likelihood of syndesmotic disruption and instability.
- The medial side determines stability. An isolated lateral malleolar fracture with medial tenderness may still be unstable — a weight-bearing or stress view answers the question.
- Always palpate the whole fibula: a proximal fibular fracture with a medial-sided injury is a Maisonneuve pattern and demands syndesmotic assessment.
- Talar shift of even a small degree markedly reduces tibiotalar contact area, which is the argument for anatomical restoration of the mortise.
- Fibular length and rotation are the two parameters to quote as governing outcome; the talocrural angle and subchondral line continuity are how you check them.
- Soft tissue timing is an answer in itself — fix early before swelling, or wait for the wrinkle sign; operating through blistered oedematous skin invites disaster.
Sources for further reading
- Rockwood and Green's Fractures in Adults — malleolar fractures chapter
- Standard operative orthopaedics textbook — fractures and dislocations of the ankle
- Apley and Solomon's System of Orthopaedics and Trauma — injuries of the ankle and foot
- AO principles of fracture management — lag screw and neutralisation plate technique
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Resident-authored study summary in original wording, not reproduced from copyrighted source text.