Ankle & Foot Injuries, Fractures & Dislocations
Comprehensive emergency evaluation and protocolized management of acute ankle and foot injuries: diagnostic criteria for the notoriously missed Lisfranc fracture-dislocation (tarsometatarsal joint complex, pathognomonic plantar ecchymosis, the 'fleck sign', and weight-bearing views); Calcaneal fractures (axial load mechanics, Böhler's angle measurement < 20 degrees, and mandatory screening for associated lumbar spine burst fractures); precise anatomical differentiation of 5th metatarsal base fractures (Zone 1 pseudo-Jones avulsion vs. Zone 2 true Jones watershed fracture); the Maisonneuve ankle-syndesmosis disruption; and Talus neck fractures with avascular necrosis surveillance.
Resuscitation Quick Actions • First 2 Minutes
Plantar Ecchymosis Rule
Ecchymosis on the PLANTAR surface of the midfoot is pathognomonic for a Lisfranc injury until proven otherwise by weight-bearing X-ray or CT
Lisfranc 'Fleck Sign'
Avulsion bone fragment in the space between the medial cuneiform and 2nd metatarsal base represents Lisfranc ligament avulsion -> Non-weight-bearing splint and Ortho
Calcaneus & Lumbar Spine
Axial impact causing calcaneus fracture is accompanied by lumbar spine burst fractures in 10% and contralateral calcaneus fractures in 10% -> Order L-spine series
Böhler's Angle Threshold
Angle formed by superior calcaneus facets on lateral view: Normal = 20 to 40 degrees; Angle < 20 degrees indicates depressed intra-articular calcaneal fracture
Zone 1 vs Zone 2 (5th Metatarsal)
Zone 1 (Pseudo-Jones/Avulsion): Hard-sole shoe, weight-bearing as tolerated; Zone 2 (True Jones): Metaphyseal-diaphyseal junction -> STRICT non-weight-bearing cast
Maisonneuve Fracture Mandate
Every ankle injury with medial tenderness or widened clear space MANDATES palpation of the PROXIMAL FIBULAR NECK to detect syndesmotic Maisonneuve fractures
Danis-Weber Classification of Ankle Fractures
Based on level of fibula fracture relative to syndesmosis: Weber A (below syndesmosis: stable), Weber B (at syndesmosis: variable stability), Weber C (above syndesmosis: unstable, syndesmotic disruption; requires surgical ORIF).
Bottom-Line Clinical Pearl
A Lisfranc injury (tarsometatarsal ligament complex disruption) is missed on initial non-weight-bearing emergency radiographs in up to 20% to 30% of cases: **PLANTAR MIDFOOT ECCHYMOSIS** is pathognomonic for rupture of the Lisfranc ligament. If an ambulatory patient cannot bear weight or has midfoot tenderness with rotational stress, obtain bilateral weight-bearing radiographs or CT imaging—missing a Lisfranc injury leads to midfoot arch collapse, chronic arthritis, and lifelong disability. In calcaneus fractures caused by high-energy vertical falls ('lover's fracture'), **ALWAYS obtain complete Thoracolumbar Spine Radiographs**: up to 10% of patients harbor an occult lumbar burst or Chance fracture.
The Lisfranc joint complex encompasses the articulations between the three cuneiforms and cuboid with the five metatarsal bases (tarsometatarsal joints). While strong transverse ligaments bind metatarsals 2 through 5, no transverse ligament exists between the 1st and 2nd metatarsal bases. The sole stabilizing structure is the stout, oblique Lisfranc Ligament, running from the plantar aspect of the medial cuneiform to the base of the 2nd metatarsal:
| Clinical Feature | Examination & Radiographic Hallmarks | Clinical Significance & Management |
|---|---|---|
| Injury Mechanism | High-energy motor vehicle collisions or low-energy athletic trauma: axial loading of a hyperplantar-flexed foot (e.g., horse rider falling with foot caught in stirrup, or football lineman falling forward onto toes). | Causes dorsal dislocation of the metatarsals relative to the midfoot. |
| Physical Examination | 1. Plantar Midfoot Ecchymosis: Bruising on the plantar surface of the arch (PATHOGNOMONIC FOR LISFRANC TEAR). 2. Midfoot swelling and exquisite tenderness over tarsometatarsal joints. 3. Pronation-Abduction Stress Test: Grasping heel and twisting forefoot elicits severe midfoot pain. | Inability to bear weight on the toes (single-leg heel raise impossible). |
| Radiographic Hallmarks (Non-Weight-Bearing vs. Weight-Bearing) | 1. Normal AP view: Medial border of the 2nd metatarsal base must align perfectly with the medial border of the middle cuneiform. 2. Normal Oblique view: Medial border of the 3rd metatarsal aligns with medial lateral cuneiform; medial border of 4th metatarsal aligns with medial cuboid. 3. The 'Fleck Sign': A tiny avulsion bone fragment in the space between the medial cuneiform and 2nd metatarsal base representing bony avulsion of the Lisfranc ligament. 4. Diastasis: Space between 1st and 2nd metatarsals > 2.0 mm. | THE WEIGHT-BEARING MANDATE: Non-weight-bearing X-rays miss up to 30% of subtle ligamentous Lisfranc tears. If patient can tolerate, obtain bilateral weight-bearing AP/lateral foot radiographs (stress of standing widens the gap). If patient cannot stand: obtain CT Foot without contrast. |
The calcaneus is the most frequently fractured tarsal bone, caused by high-energy vertical axial compression (fall from height landing on heels ['Don Juan' or 'lover's fracture']). Over 75% are intra-articular fractures involving the subtalar joint:
| Parameter/Sign | Measurement & Finding | Associated Traumatic Hazards |
|---|---|---|
| Böhler's Angle Measurement | Measured on a lateral foot radiograph: - Draw line 1: Highest point of the posterior calcaneal tuberosity to the highest point of the posterior subtalar facet. - Draw line 2: Highest point of the posterior subtalar facet to the highest point of the anterior superior calcaneal process. - Measure the superior angle formed. | Normal Böhler's Angle = 20 to 40 degrees. An angle < 20 degrees indicates significant posterior facet depression and articular collapse from an intra-articular fracture. |
| The 'Rule of 10s' in Calcaneus Fractures | 1. 10% Associated Lumbar Spine Fractures: Axial compressive load drives force up the kinetic chain into the thoracolumbar junction (Chance fracture/burst fracture). 2. 10% Bilateral Calcaneus Fractures. 3. 10% Associated Compartment Syndrome of the Foot. | MANDATORY RADIOGRAPHIC WORKUP: Every patient with a calcaneus fracture must have AP and lateral radiographs of the Thoracic and Lumbar spine, regardless of whether back pain is reported! |
| Emergency Management | Bulky, well-padded posterior splint with stirrups (Jones dressing), ice, strict limb elevation above the heart, and non-weight-bearing with crutches. Stat Orthopedic consultation. |
| Anatomical Zone | Pathophysiology & Fracture Location | Vascularity & Emergency Management |
|---|---|---|
| Zone 1: Pseudo-Jones/Avulsion Fracture (Dancer's Fracture) (Most Common: 90%) | Avulsion of the tuberosity at the proximal tip of the 5th metatarsal base by the lateral band of the plantar aponeurosis or peroneus brevis tendon during sudden inversion of a plantar-flexed foot. | Excellent Blood Supply (cancellous bone with rich metaphyseal circulation). - Management: Symptomatic treatment: Stiff-soled post-op shoe or walking boot; weight-bearing as tolerated. Heals reliably without non-union in 4-6 weeks. |
| Zone 2: True Jones Fracture (Metaphyseal-Diaphyseal Junction) | Transverse fracture located at the junction of the metaphysis and diaphysis, within 1.5 cm distal to the tuberosity, entering the intermetatarsal articulation between the 4th and 5th metatarsals. | VASCULAR WATERSHED AREA: Poor intramedullary blood supply. High risk of non-union or delayed union (> 30-50%)! - Management: STRICT NON-WEIGHT-BEARING SHORT-LEG SPLINT/CAST for 6 to 8 weeks; urgent Orthopedic referral (athletes often undergo primary percutaneous screw fixation). |
| Zone 3: Proximal Diaphyseal Stress Fracture | Repetitive microtrauma in runners/military recruits distal to the intermetatarsal joint. | High non-union rate; non-weight-bearing cast or surgical intramedullary screw. |
| Condition | Biomechanical Mechanism & Anatomy | Clinical Examination & Pitfalls |
|---|---|---|
| Maisonneuve Fracture (The Missed Proximal Fibula) | Pronation-external rotation injury: 1. Rupture of the deltoid ligament (or medial malleolus avulsion fracture). 2. Complete disruption of the tibiofibular syndesmosis and interosseous membrane up the entire length of the lower leg. 3. Spiral fracture of the proximal fibular neck. | Patient presents complaining only of severe medial ankle pain. Ankle X-ray shows widened medial clear space (> 4 mm) or medial malleolar fracture without a distal lateral malleolus fracture. MANDATORY CLINICAL RULE: ALWAYS PALPATE THE ENTIRE FIBULA UP TO THE FIBULAR HEAD! Palpation reveals point tenderness; obtain dedicated Full-Length Tibia-Fibula Radiographs. Management: Highly unstable; requires operative syndesmotic screw fixation. |
| Talus Fractures & Hawkins Classification | High-energy dorsiflexion impacts (dashboard against brake pedal). - High rate of Avascular Necrosis (AVN) of the talar body due to retrograde blood supply through the artery of the tarsal canal. - Hawkins Sign (good prognostic sign): Subchondral radiolucency of the talar dome on AP X-ray at 6-8 weeks proves preserved vascularity (resorption of bone requires blood flow!). | Displaced talus neck fractures require emergent anatomical closed reduction and emergent Orthopedic admission for internal fixation. |
The Missed Lisfranc Arch Collapse & The Overlooked Lumbar Burst Fracture
Two major orthopedic pitfalls must be prevented in foot trauma. First, never diagnose a patient with a 'mild midfoot sprain' if they have ecchymosis on the plantar surface of the foot: plantar ecchymosis is pathognomonic for a Lisfranc fracture-dislocation. Non-weight-bearing radiographs miss up to 30% of these injuries because the elastic midfoot recoil partially closes the gap when the foot is dangling in the air. If the patient has midfoot tenderness or cannot bear weight on their toes, obtain bilateral weight-bearing radiographs or a non-contrast CT of the foot: failing to immobilize and surgically stabilize a Lisfranc injury leads to complete collapse of the longitudinal arch, severe rocker-bottom foot deformity, and permanent disability. Second, in any patient presenting with a calcaneal fracture after falling from a ladder or roof, ALWAYS EXAMINE AND RADIOGRAPH THE THORACOLUMBAR SPINE: up to 10% of calcaneus fracture patients have a simultaneous lumbar burst fracture (Chance fracture) from axial force transmission up the spine. Missing an unstable lumbar burst fracture while focusing on the swollen heel will result in secondary spinal cord compression and catastrophic paraplegia upon ambulation.
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