Isolated vs. Syndesmotic Injury | Maisonneuve Fracture | Management
Injury Patterns
Critical Must-Knows
- Isolated fibular shaft fractures are stable and treated non-operatively (WBAT in boot).
- Maisonneuve fracture: Proximal fibular fracture + medial malleolus fracture/deltoid ligament rupture + syndesmosis injury. Unstable.
- Common Peroneal Nerve runs around femoral neck/proximal fibula - assess motor (EHL/TA) and sensation (dorsum foot).
- Syndesmosis assessment is critical - use gravity stress view or ER stress view if suspicious.
- Tibial shaft fractures often have associated fibular fractures - intact fibula may prevent reduction (strut effect).
Clinical Pearls
- "Always examine the medial ankle (tenderness = deltoid injury) in proximal fibular fractures.
- "Isolated fibular shaft fracture = 'Ankle sprain of the bone' → Treat symptoms.
- "Bilateral ankle X-rays (weight bearing) are gold standard for assessment.
- "Missed Maisonneuve = Chronic ankle instability/pain.
Clinical Imaging
Imaging Gallery


Critical: Rule Out Maisonneuve
The 'Isolated' Trap
Proximal fibular fracture is rarely isolated. It is often part of a rotational ankle injury (PER stage). You MUST examine the medial ankle (deltoid ligament) and syndesmosis.
Nerve Check
Common Peroneal Nerve (CPN) palsy: Foot drop (weak dorsiflexion/eversion) and numb dorsal foot. Check before and after any intervention.
Compartment Syndrome
Rare in isolated fibula, but common in associated tibia-fibula fractures. Monitor pain out of proportion.
The Intact Fibula
In tibial shaft fractures, an intact fibula can be a problem. It acts as a strut, preventing compression or reduction of the tibia (keeps it in varus).
Fibular Fracture Patterns and Management
| Pattern | Mechanism | Stability | Treatment |
|---|---|---|---|
| Isolated Shaft | Direct blow | Stable | Walking boot / WBAT |
| Maisonneuve | External rotation | Unstable (Syndesmosis) | Surgery (Syndesmotic screws/buttons) |
| With Tibial Shaft | High energy | Unstable (Tibial) | Treat Tibia (IM Nail/Plate) |
| Stress Fracture | Repetitive load | Stable | Activity modification / Boot |
MINDMaisonneuve Examination
| M | Medial ankle Check tenderness (Deltoid) or fracture |
| I | Interosseous Syndesmosis tenderness up the leg |
| N | Neck of fibula Fracture site (Proximal) |
| D | Dorsiflexion Check CPN function (nerve wraps neck) |
| M | Medial ankle Check tenderness (Deltoid) or fracture | N | Neck of fibula Fracture site (Proximal) |
| I | Interosseous Syndesmosis tenderness up the leg | D | Dorsiflexion Check CPN function (nerve wraps neck) |
Hook:Keep Maisonneuve in MIND for any ankle injury!
BOOTTreatment of Isolated Fibula
| B | Boot Walking boot for comfort |
| O | Observe Monitor for healing |
| O | On feet Weight bear as tolerated (WBAT) |
| T | Time Heals in 4-6 weeks |
| B | Boot Walking boot for comfort | O | On feet Weight bear as tolerated (WBAT) |
| O | Observe Monitor for healing | T | Time Heals in 4-6 weeks |
Hook:Isolated fibula? Give 'em the BOOT!
OPENIndications for Surgery
| O | Open fracture Debridement and fixation |
| P | Palsy (CPN) Explore if nerve entrapped (rare) |
| E | Entrapment Tibia reduction blocked by fibula |
| N | Non-union Symptomatic non-union (rare) |
| O | Open fracture Debridement and fixation | E | Entrapment Tibia reduction blocked by fibula |
| P | Palsy (CPN) Explore if nerve entrapped (rare) | N | Non-union Symptomatic non-union (rare) |
Hook:When to OPEN a fibula fracture.
Overview and Epidemiology
Fibular shaft fractures involve the diaphysis of the fibula. They can occur as isolated injuries (direct blow) or as part of a complex ankle or leg injury (Maisonneuve, Tibia-Fibula fracture).
Mechanism of Injury
- Direct Blow: "Nightstick" fracture. Isolated transverse fracture. Stable. This is typically sustained in contact sports like soccer or rugby where a direct kick or impact occurs to the lateral leg.
- Rotational Force: External rotation of ankle. Energy transmits through syndesmosis → proximal fibula fracture (Maisonneuve). Unstable. The medial structures (deltoid) fail first, then the syndesmosis, then the fibula.
- Axial Load: Fall from height. Usually associated with tibial fracture. The fibula fails under compression, often resulting in comminution.
The Maisonneuve Force Transmission
Force travels in a circle: Medial ankle (deltoid release) → Synergy check (syndesmosis tear) → Exit via proximal fibula fracture. Always check the whole circle!
Epidemiology
- Incidence: Common fracture in active adults. Fibula fractures (including malleolar) constitute a significant portion of ankle trauma.
- Isolated: Football/Soccer (direct kick) is the most common cause.
- Prognosis: Isolated = Excellent union rates. Associated = Depends on other injuries (tibial alignment, chondral damage).
- Risk Factors: Contact sports, osteoporosis in elderly. In the elderly population, fibula fractures may be part of fragility fractures of the ankle.
Anatomy and Pathophysiology
Anatomy
The fibula acts as a strut for muscle attachment and ankle stability, but plays a minor role in weight transmission.
- Fibula Structure: Long, slender bone. The head is proximal, articulating with the tibia. The neck is just distal to the head (nerve risk). The shaft is triangular in cross-section. The distal end forms the lateral malleolus.
- Weight Bearing: The fibula bears approximately 6-17% of the body's load. This minimal load-bearing allows for fibular resection (e.g., for bone grafts) without significant functional deficit, provided the distal syndesmosis is intact.
- Interosseous Membrane (IOM): A strong fibrous sheet connecting the tibia and fibula. It provides stability for the ankle mortise and serves as an origin for muscles. The fibers run obliquely from proximal-medial (tibia) to distal-lateral (fibula), resisting distal migration of the fibula.
- Common Peroneal Nerve (CPN): The nerve winds around the neck of the fibula, passing from the popliteal fossa into the anterior and lateral compartments. It is highly susceptible to injury here from direct trauma, casts, or surgical retractors.
- Deep Peroneal Nerve: Supplies the Anterior compartment (Tibialis Anterior, EHL, EDL). Function: Dorsiflexion. Sensation: First dorsal web space.
- Superficial Peroneal Nerve: Supplies the Lateral compartment (Peroneus Longus/Brevis). Function: Eversion. Sensation: Dorsum of the foot (except 1st web space). Pierces the deep fascia in the distal third of the leg.
- Syndesmosis: The distal tibiofibular joint is maintained by the Anterior Inferior Tibiofibular Ligament (AITFL), Posterior Inferior Tibiofibular Ligament (PITFL), Transverse Ligament, and the distal IOM. It prevents diastasis (widening) of the ankle mortise.
Vascular Supply
- Peroneal Artery: The nutrient artery typically enters the middle third of the fibular shaft.
- Periosteal Supply: The fibula receives a rich blood supply from its multiple muscle attachments (Soleus, Peroneals, Tibialis Posterior, EHL).
- Clinical Relevance:
- The robust vascularity contributes to high union rates, even in displaced fractures.
- The middle third of the fibula is the "workhorse" donor site for vascularized bone grafts (e.g., for mandibular or tibial reconstruction) because of its predictable pedicle (peroneal vessels).
- The distal third has a relatively poorer blood supply, closer to the watershed area of the ankle, which can impact wound healing in surgical cases.
Pathophysiology
- Stability: The fibular shaft itself is not essential for weight bearing stability in the mid-diaphysis. However, the proximal and distal ends are critical for knee (LCL attachment) and ankle stability.
- Ankle Mortise: The Lateral Malleolus (distal fibula) acts as a buttress to prevent lateral shift of the talus. Even 1mm of lateral shift can reduce tibio-talar contact area by 42%, leading to early osteoarthritis.
- Maisonneuve Fracture: A spiral fracture of the proximal third of the fibula associated with a rotational ankle injury. The fracture line location is an indicator of the exit point of the rotational force. If the force exits proximally, it implies that the energy has traveled through the interosseous membrane and syndesmosis, rupturing them.
- Healing: The fibula has a rich muscle envelope (peroneals, soleus, tibialis posterior) which provides excellent blood supply. Non-union is rare. Malunion is generally well tolerated unless it affects the ankle mortise.
Nerve Anatomy
The Common Peroneal Nerve divides into Deep and Superficial branches just distal to the fibular head. It is vulnerable to direct trauma or pressure from casts/splints. Always document EHL function (Big toe extension) specifically as a sensitive indicator of Deep Peroneal Nerve function.
Classification Systems
AO/OTA Classification (4F2)
The AO/OTA classification describes the morphology of the fracture.
4F2: Fibula Diaphysis
- A: Simple (Spiral, Oblique, Transverse)
- A1: Spiral
- A2: Oblique (greater than 30 degrees)
- A3: Transverse (less than 30 degrees)
- B: Wedge (Intact wedge, Fragmented wedge)
- B2: Intact wedge
- B3: Fragmented wedge
- C: Complex (Comminuted)
- C2: Intact segmental
- C3: Irregular
Note: If Tibia is fractured, it is classified under Tibia (42) with fibula modifier.
Utility: While descriptive, the AO classification for isolated fibula fractures does not strongly dictate treatment, as most are treated non-operatively regardless of comminution. Its main value is in research and database tracking.
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Clinical Assessment
History
- Mechanism: Was it a direct blow (e.g., hockey stick, kick)? This suggests an isolated fracture. Was it a twisting injury? This suggests a rotational component and possible syndesmotic injury.
- Pain: Location of pain is key. Mid-calf pain vs Ankle pain. Patients with Maisonneuve fractures may complain only of ankle pain and the proximal fibula tenderness is missed if not palpated.
- Ambulation: Patients with isolated fibula fractures can often bear weight, though painful. Patients with unstable syndesmotic injuries usually cannot.
Physical Examination
- Inspection: Look for deformity, swelling, and bruising. Note any skin tenting or open wounds (rare in isolated fibula). Look specifically for medial ankle bruising ("ecchymosis").
- Palpation:
- Fibula: Palpate the entire length. The "Squeeze test" (compressing tibia and fibula together at mid-calf) causing distal pain suggests syndesmosis injury.
- Medial Ankle: Tenderness over the deltoid ligament or medial malleolus is the "red flag" for Maisonneuve.
- Syndesmosis: Tenderness over the AITFL (anterior ankle).
- Neurovascular Status:
- Motor: Check Dorsiflexion (Tib Ant) and Great Toe Extension (EHL) for Deep Peroneal Nerve. Check Eversion (Peroneals) for Superficial Peroneal Nerve.
- Sensory: Check first web space (Deep) and dorsum of foot (Superficial).
- Pulses: Dorsalis Pedis and Posterior Tibialis.
- Knee: Always assess the knee to rule out associated injuries (LCL, PLC) or proximal tib-fib joint dislocation.
Investigations
Standard Series
- Tibia/Fibula: AP and Lateral. Must include adjacent joints ("One joint above and below"). This rules out proximal extension or associated tibial fractures.
- Ankle: Three views (AP, Lateral, Mortise). Weight Bearing views are the gold standard if the patient can tolerate it, as they stress the syndesmosis physiologically.
Radiographic Params (Mortise View):
- Medial Clear Space (MCS): Should be equal to the superior clear space. greater than 4mm suggests deltoid rupture/instability.
- Tibiofibular Clear Space (TFCS): Distance between medial fibular border and incisura. Should be less than 6mm.
- Tibiofibular Overlap (TFO): Overlap of fibula and tibia. Should be greater than 1mm on Mortise view (greater than 6mm on AP).
- Talar Shift: Lateral displacement of the talus.
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Differential Diagnosis
The "lateral leg / ankle pain after a twist or blow" presentation has several mimics. The critical task is separating a benign isolated shaft fracture from an unstable rotational injury.
Distinguishing Fibular Pain Mimics
| Diagnosis | Key Discriminator | Stability / Action |
|---|---|---|
| Isolated fibular shaft fracture | Direct-blow mechanism, focal mid-shaft tenderness, no medial tenderness, normal mortise | Stable - boot, WBAT |
| Maisonneuve fracture | Twisting mechanism, proximal fibula tenderness plus medial ankle tenderness, widened medial clear space | Unstable - syndesmotic fixation |
| Weber B/C malleolar fracture | Fracture at/below or above the plafond on ankle films, talar shift | Stress-dependent - often ORIF |
| High ankle (syndesmotic) sprain without fracture | Positive squeeze/ER test, AITFL tenderness, no cortical break | Variable - stress views to exclude latent diastasis |
| Fibular stress fracture | Insidious load-related pain in runner/recruit, distal third, no acute trauma | Stable - relative rest, boot |
| Lateral ankle ligament sprain | Pain anterior to lateral malleolus, normal proximal fibula, negative squeeze | Stable - functional rehab |
| Proximal tib-fib dislocation / PLC avulsion | Fibular head pain, knee instability, LCL/biceps avulsion | Knee-driven - assess PLC |
Management Algorithm

Decision Pathway
Fibular Fracture Management
Is it isolated? Check medial ankle. Check syndesmosis integrity (Stress view). If Medial Clear Space less than 4mm → Stable.
Isolated shaft fracture. Treatment: Symptomatic. Walking boot or stirrup brace. WBAT immediately.
Maisonneuve or Syndesmotic injury. Treatment: Syndesmotic fixation (Screw or TightRope). Fibula rarely needs plating.
Associated with tibia fracture. Treatment: Fix tibia (IM Nail). Fibula usually ignored unless Syndesmosis disrupted or blocking reduction.
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Surgical Technique
Syndesmosis Fixation (For Maisonneuve)
This is the primary surgery for unstable "fibular shaft" fractures (Maisonneuve). The goal is to stabilize the fork (mortise), not necessarily the fibula shaft.
- Setup: Supine, sandbag under ipsilateral gluteal. Tourniquet. C-arm.
- Approach: Lateral ankle incision (distal). Visualize the syndesmosis directly if needed.
- Reduction:
- Use a large reduction clamp (pelvic or lobster claw).
- One tine on the fibula, one on the medial tibia.
- Reduce the fibula into the incisura of the tibia.
- Tip: Do not over-compress. Ensure the fibula is not fixed in posterior translation.
- Position: Traditional teaching held the ankle in neutral dorsiflexion during fixation to avoid over-tightening, though recent evidence suggests ankle position matters less than clamp position and fibular rotation.
- Fixation:
- Screws: 1 or 2 quadricortical screws (crossing 4 cortices) or tricortical. 3.5mm or 4.5mm. Placed 2-3cm above joint line.
- Suture Button (TightRope): Drill bone tunnel through fibula and tibia. Pass button mechanism. Tighten. Allows flexible, physiologic motion.
- Verification: Intra-op stress test ("Cotton test" - lateral pull on fibula with hook) or External Rotation stress under fluoroscopy.
The proximal fibula fracture is left alone to heal.
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CPN Protection
In proximal fibula surgery or plating, the Common Peroneal Nerve is at high risk. Identify and protect. If unsure, avoid proximal dissection and use MIPO (Minimally Invasive Plate Osteosynthesis) or manage non-operatively if possible.
Complications
| Complication | Risk | Management |
|---|---|---|
| Non-union | Low (less than 1%) | Symptomatic? Bone graft + Plate. |
| Malunion | Low | Usually well tolerated. Resection osteotomy if needed. |
| CPN Palsy | Variable | AFO (Splint). Explore if iatrogenic. |
| Chronic Pain | Variable | Physiotherapy. Check for missed syndesmosis/chondral injury. |
| Hardware Pain | Medium | Remove screws/plate after union. |
Missed Syndesmosis
Leading cause of poor outcome in "isolated" fibula fractures. Results in chronic instability, Talar shift, and early post-traumatic arthritis. Requires reconstruction with graft (e.g., semitendinosus) or arthrodesis if late degeneration occurs.
Compartment Syndrome
Check in high-energy injuries or crush injuries. Be vigilant in "tight" leg compartments (Anterior/Lateral). Pain out of proportion to injury, pain with passive stretch of toes. Isolated fibula compartment syndrome is rare but can occur with direct crush.
Superficial Peroneal Nerve Entrapment
- Pathology: The Superficial Peroneal Nerve (SPN) pierces the deep fascia in the distal third of the leg, making it vulnerable to tethering in fracture callus or surgical scar tissue.
- Risk: Higher risk with lateral approaches or percutaneous pin placement.
- Presentation: Patients complain of burning pain over the dorsum of the foot, often exacerbated by inversion and plantarflexion (stretching the nerve).
- Signs: Positive Tinel's sign over the scar/fracture site. Sensation may be altered over the dorsum of the foot.
- Management: Desensitization massage, Gabapentin. Surgical neurolysis is reserved for refractory cases.
Complex Regional Pain Syndrome (CRPS)
Can occur after any ankle trauma. Early mobilization and Vitamin C may reduce risk.
Nerve Injury
The Superficial Peroneal Nerve is at risk during lateral approaches (distal third), and the Common Peroneal Nerve is at risk during proximal approaches or from the injury itself. Symptomatic neuromas may require surgical excision.
Postoperative Care
Non-Operative (Isolated)
- 0-2 Weeks: Boot, WBAT with crutches for comfort. Elevate to reduce swelling.
- 2-6 Weeks: Wean boot. Transition to supportive shoe/brace. Start Physio for ROM (Ankle alphabet) and strengthening (Peroneals/Calf).
- 6+ Weeks: Return to impact activities as pain allows. Most patients return to full sports by 8-12 weeks.
- Milestones:
- Full weight bearing without pain.
- Equal ankle dorsiflexion/plantarflexion.
- Ability to perform single leg hop.
Operative (Syndesmosis)
- 0-2 Weeks: Non-weight bearing (NWB) cast/splint using crutches. Elevation. Wound check at 2 weeks.
- 2-6 Weeks: NWB in tall boot. Range of Motion exercises allowed (Active dorsiflexion/plantarflexion). Avoid external rotation. Protocol varies widely: Suture buttons (TightRope) often allow earlier weight bearing (e.g., WBAT at 2 weeks) compared to rigid screws.
- 6-12 Weeks: Progressive weight bearing. Proprioception training (wobble board). Strengthening (theraband).
- Hardware Removal:
- Rigid Screws: Traditionally removed at 3-4 months before full unrestricted activity to prevent screw breakage. Activity is restricted until removal and then screw holes heal (6 weeks).
- Suture Buttons: Stay in permanently unless symptomatic (knot irritation). No activity restriction once healed.
Rehabilitation Protocol Details (Syndesmosis)
- Phase 1 (0-6 Weeks): Protection and Edema Control
- Goals: Heal soft tissues, protect fixation.
- Exercises: Toe curls, Knee ROM, Hip strengthening (Straight Leg Raises).
- Precautions: No weight bearing (for screws). No external rotation torque.
- Phase 2 (6-10 Weeks): Mobility and Strength
- Goals: Restore full ROM, normalize gait.
- Exercises: Calf stretching (gastroc/soleus), Ankle 4-way theraband strengthening, Stationary bike (low resistance).
- Proprioception: Single leg stance eyes open/closed.
- Phase 3 (10+ Weeks): Return to Function
- Goals: Power, Agility, Sport-specific skills.
- Exercises: Heel raises (bilateral to single), Plyometrics (box jumps, hopping), Running progression (Walk-Jog-Run).
- Testing: Hop test (greater than 90% of contralateral side) required for cleared return to play.
DVT Prophylaxis
Chemical thromboprophylaxis (LMWH or Aspirin) is debated for isolated fibular fractures treated in a boot. Current guidelines often suggest it for patients with risk factors (e.g., previous DVT, obesity, OCP) who are immobilized. Assess using a risk stratification tool.
Outcomes and Prognosis
Isolated Fibula
- Excellent. 95%+ of patients return to pre-injury level of activity.
- Rapid healing. Pain resolves by 3-4 months usually.
- Long-term functional deficits are rare.
Maisonneuve
- Good, if syndesmosis reduced accurately.
- Risk: Ankle arthritis if reduction is poor (fibula malreduced or syndesmosis widened).
- Stiffness: Stiffer ankle compared to isolated fractures.
- Recovery: Takes longer (6-9 months) for full sports return compared to isolated injuries.
Controversies and Areas of Uncertainty
- Screw vs suture button for the syndesmosis: Level I meta-analysis favours suture buttons for function and lower reoperation, but a long-term RCT found malreduction and osteoarthritis rates comparable between the two. Reduction quality may matter more than the implant chosen.
- Routine syndesmosis screw removal: Traditionally removed before return to full activity, yet many intact screws are asymptomatic. Practice is shifting to removing only symptomatic implants.
- Which "isolated" fibula fractures are truly stable: Static radiographs miss latent instability. Reliance on gravity/external-rotation stress views versus weight-bearing radiographs versus MRI to declare stability remains debated.
- Number, size and cortices of screws: Quadricortical vs tricortical, 3.5 vs 4.5mm, one vs two screws - no consensus; the trend is toward fewer, smaller, or flexible constructs.
- Ankle position during syndesmotic fixation: The old teaching to hold maximal dorsiflexion to avoid "over-tightening" is now largely discredited; clamp position and rotation are the real determinants of malreduction.
- Significance of fibular shortening/malunion: Mid-diaphyseal fibula malunion is usually well tolerated, but the threshold of shortening that alters ankle mechanics is poorly defined.
- Thromboprophylaxis for boot-treated isolated fractures: Routine chemical prophylaxis is not supported for low-risk patients; risk-stratified use is recommended but thresholds vary by guideline.
Prevention and Return to Sport
- Protective Gear: Shin guards (Soccer) are effective in preventing direct blow fractures ("Nightstick").
- Return to Play:
- Isolated: 4-8 weeks. Criteria: Pain-free hopping, full strength, full ROM.
- Maisonneuve: 4-6 months. Requires solid syndesmotic healing and rehab.
Evidence Base
Operative vs Non-operative for Unstable Lateral Malleolar (Isolated Fibula) Fractures
- Randomised multicentre trial of 81 patients with undisplaced but unstable isolated fibula fractures (medial clear space 5mm or more on external rotation stress).
- No statistically significant difference in Olerud-Molander or SF-36 functional outcome between operative and non-operative groups at any time point.
- Non-operative group had higher rates of late displacement (medial clear space 5mm or more in 8 patients) and delayed/non-union (8 patients); operative group had 5 infections and 5 hardware removals.
The Proximal Fibula Must Be Examined in All Ankle Injuries: Missed Maisonneuve Fractures
- Five patients with Maisonneuve fractures were missed at first presentation despite ankle radiographs because examination focused on the ankle.
- Most patients reported severe ankle pain but little pain over the proximal fibula fracture.
- All five ultimately required open reduction and internal fixation.
Suture Button vs Syndesmotic Screw: Meta-analysis of RCTs
- Meta-analysis of 5 RCTs (143 suture button vs 142 screw patients).
- Suture button gave higher mean AOFAS score (95.3 vs 86.7) at a mean 20.8 months.
- Suture button had lower rates of broken implant (0% vs 25.4%), implant removal (6.0% vs 22.4%) and malreduction (0.8% vs 11.5%).
Syndesmotic Malreduction Is Common and Under-detected on Plain Films
- Postoperative CT of 25 ankles with syndesmotic fixation showed incongruity (malreduction) in 52% (13/25), averaging 3.6mm.
- Plain radiographs detected only 4 of these, giving a sensitivity of just 31% versus CT.
- Most malreductions involved internal rotation or anterior translation of the fibula.
Tibial Fractures with an Intact Fibula: The Strut Effect
- In 23 adults with tibial shaft fracture and intact fibula, 26% developed delayed union or non-union and 26% developed varus malunion.
- Biomechanical testing showed an intact fibula creates a tibiofibular length discrepancy and altered tibial strain, predisposing to malunion/non-union.
- Younger patients (under 20) had fewer complications, attributed to greater fibular compliance.
Distal Tibiofibular Syndesmosis Anatomy and the Cost of Mortise Widening
- Detailed multimodality description of the four syndesmotic ligaments (AITFL, PITFL, transverse, interosseous).
- Widening of the ankle mortise by just 1mm decreases tibiotalar contact area by 42%.
- Syndesmotic injury occurs in about 50% of Weber B and effectively all Weber C ankle fractures.
Immediate vs Restricted Weight-bearing after Ankle Fracture ORIF (INWN Trial)
- Pragmatic multicentre RCT comparing immediate weight-bearing plus early range of motion within 24h against 6 weeks of non-weight-bearing cast immobilisation after ankle fracture ORIF.
- Primary outcome is the functional Olerud-Molander Ankle Score, reflecting a shift away from prolonged immobilisation.
- Reflects emerging evidence that early weight-bearing gives comparable function with greater patient satisfaction, balanced against possible wound complications.
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: The 'Sprained Ankle'
"A 25-year-old soccer player presents with a 'high ankle sprain'. X-ray shows a proximal fibula fracture."
Scenario 2: Isolated Direct Blow
"A hockey player took a stick to the leg. Isolated mid-shaft transverse fracture. Ankle stable. N/V intact."
Scenario 3: Nerve Injury
"Post-op patient after fibula plating has inability to dorsiflex big toe."
MCQ Practice Points
Most Likely Missed Injury
Q: What is the most commonly missed aspect of an isolated fibula fracture? A: Syndesmosis injury (Maisonneuve). Always squeeze the calf and check the medial ankle.
Nerve Injury
Q: Which nerve is at risk with fractures of the fibular neck? A: Common Peroneal Nerve - causes foot drop and numbness on the dorsum of the foot.
Treatment
Q: Treatment for a closed, neurovascularly intact, isolated mid-shaft fibula fracture? A: Non-operative - WBAT in a boot. It is a stable injury.
Associated Tibia
Q: In a tibia shaft fracture, what role does the fibula play? A: Strut. An intact fibula may prevent varus correction of the tibia.
Stress Fracture
Q: What is the most common location for fibular stress fractures? A: Distal third (6-7cm above lateral malleolus) - Common in runners and military recruits due to repetitive loading.
Segond Equivalent
Q: A proximal fibula avulsion fracture in the setting of a knee injury indicates what? A: Posterolateral corner (PLC) injury - The LCL and biceps femoris insert on the fibular head; avulsion suggests significant knee ligament damage.
Guidelines, Registries & Global Practice
Global Epidemiology
- Ankle fractures (of which the fibula is the most frequently involved bone) occur at roughly 100-180 per 100,000 person-years, with a bimodal distribution: young men from sport/high-energy injury and older women from fragility fractures.
- Isolated diaphyseal ("nightstick") fibula fractures are most common in contact and kicking sports (soccer/football, rugby, hockey) where a direct blow strikes the lateral leg.
- Maisonneuve fractures represent a small but high-stakes subset; they are disproportionately represented among "missed" rotational ankle injuries.
Side-by-side Guidance
How Major Bodies Frame Fibula and Syndesmosis Injury
| Body | Emphasis | Practical Recommendation |
|---|---|---|
| AO Foundation | Mechanism and mortise restoration | Reduce and stabilise the syndesmosis anatomically; the fibula sets ankle length and rotation |
| BOA / BOAST (UK) | Soft tissues and timely fixation | Document neurovascular status; operate before significant swelling or after it settles; weight-bear early when stable |
| AAOS (US) | Evidence-based stability assessment | Stress testing to distinguish stable from unstable lateral malleolar/fibula fractures before committing to non-operative care |
| EFORT / European consensus | Syndesmosis reduction quality | Favours direct visualisation or intra-operative CT to avoid malreduction; flexible fixation increasingly preferred |
Registry and System Notes
- National arthroplasty/trauma registries (AOANJRR, NJR, SHAR) track ankle fracture fixation as a high-volume procedure; metalwork removal (notably syndesmosis screws) is a frequent secondary procedure, a burden that suture-button fixation aims to reduce.
- Routine removal of intact syndesmosis screws is now questioned; many systems remove only symptomatic implants.
High- vs Limited-resource Practice
- Well-resourced settings: stress radiographs or CT for equivocal syndesmosis, suture-button options, formal physiotherapy-led rehabilitation, early weight-bearing protocols.
- Limited-resource settings: reliance on plain radiographs and clinical examination (proximal fibula palpation, medial tenderness, calf squeeze); cast or boot immobilisation; syndesmotic screws preferred over costlier suture-button devices, with later removal where feasible.
- The universal, resource-independent priority is the same: do not miss the unstable medial side or a proximal (Maisonneuve) fibula fracture.
FIBULAR SHAFT FRACTURES
Clinical summary
Key Concepts
- •Isolated usually = Stable
- •Proximal fracture = check Ankle (Maisonneuve)
- •Distal fracture = check Syndesmosis
- •Common Peroneal Nerve risk
Management
- •Stable: Boot, WBAT, 4-6 weeks
- •Unstable (Syndesmosis): Surgery
- •Open: Debride & Fix
- •Tibia associated: Fix Tibia
Complications
- •Missed Syndesmosis (Early Arthritis)
- •CPN Palsy (Foot Drop)
- •Non-union (Rare)
- •Compartment Syndrome (with Tibia)
Exam Quotes
- •The fibula is the lighthouse of the ankle
- •Always X-ray one joint above and below
- •Don't forget the medial ankle tenderness
- •Respect the soft tissues