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OR2.10-13 | Lower Limb Fractures — Practice Quiz
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A 28-year-old motorcyclist is brought to the emergency department after a road traffic accident. He complains of severe pain in his right thigh, the thigh is grossly swollen and externally rotated with shortening of the limb. Radiograph confirms a mid-shaft femur fracture. Six hours post-splinting he develops tachycardia (HR 112/min), SpO2 drops to 88% on room air, petechiae appear over the chest and conjunctiva, and he becomes confused. Which of the following is the most likely diagnosis?
Correct. Fat embolism syndrome after femoral shaft fracture classically presents with the triad: hypoxaemia, neurological dysfunction, and petechiae (especially over the chest, axillae, and conjunctiva). Early intramedullary nailing reduces fat embolism risk.
Fat embolism syndrome (FES) classically follows long bone (especially femoral shaft) fractures. The triad of hypoxia, cerebral dysfunction, and petechiae appearing 24–72 hours post-injury is diagnostic. Serum fat globules, lipuria, and a PaO2 <60 mmHg support the diagnosis.
Reconsider. The petechiae over the chest and conjunctivae combined with hypoxia and confusion within hours of a femoral shaft fracture is the classic triad of fat embolism syndrome, not pulmonary thromboembolism or pneumothorax.
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A 35-year-old man sustains a blow to the anterior knee during a football match. He cannot straight-leg raise and has a palpable gap at the patella. Radiograph shows transverse fracture of the patella with 5 mm separation. What is the most appropriate management?
Correct. Displaced transverse patella fractures with disruption of the extensor mechanism require open reduction and tension band wiring to restore the extensor apparatus and allow early mobilisation.
Displaced patella fractures (>2 mm gap or >2 mm articular step) require surgical fixation — commonly tension band wiring (TBW). The extensor mechanism must be restored. Non-displaced fractures (<2 mm) are treated conservatively in a cylinder cast.
With a 5 mm gap and inability to straight-leg raise, the extensor mechanism is disrupted — conservative management alone is insufficient. Surgical fixation with tension band wiring is required.
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A 19-year-old woman fell from a height and sustained a fracture of the proximal tibia. She is admitted for observation. Eight hours later she develops severe pain in the leg, described as worse with passive stretching of the toes, the calf is tense, the pulse is palpable, and sensation is decreased in the first web space. What should be done immediately?
Correct. Compartment syndrome is a clinical diagnosis — a palpable pulse does NOT exclude it. Fasciotomy is indicated when delta pressure (diastolic BP minus compartment pressure) is <30 mmHg. Delay causes irreversible muscle and nerve necrosis (Volkmann's contracture).
Compartment syndrome is diagnosed clinically by pain with passive stretch, tense compartment, and paresthesia — a palpable pulse does NOT exclude compartment syndrome. The key diagnostic criterion for fasciotomy is a compartment pressure delta (diastolic BP minus compartment pressure) <30 mmHg. Immediate fasciotomy is life-/limb-saving.
A palpable pulse does not exclude compartment syndrome — this is a critical known trap. The combination of pain with passive stretch, tense compartment, and neurological deficit demands compartment pressure measurement and urgent fasciotomy.
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A 55-year-old obese woman twists her ankle stepping off a kerb. Radiographs show a bimalleolar ankle fracture with lateral talar shift of 3 mm. On the anteroposterior view, the medial clear space is 5 mm. What is the management of choice?
Correct. Unstable bimalleolar fractures with talar shift require ORIF to restore the ankle mortise. Lateral malleolus is fixed with a plate; medial malleolus with cancellous screws or tension band wiring. Residual talar shift leads to post-traumatic arthritis.
Bimalleolar ankle fractures with talar shift (medial clear space >4 mm or lateral talar shift >2 mm on mortise view) are unstable and require open reduction and internal fixation (ORIF). Stability of the ankle mortise is paramount; fibula length and rotation must be restored.
With a medial clear space of 5 mm and lateral talar shift, this is an unstable injury. Conservative management cannot maintain reduction. ORIF is required.
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A 12-year-old boy fell from a bicycle and sustained a fracture through the growth plate of the distal femur. Radiograph shows the fracture line passing through the physis and extending into the metaphysis without involving the epiphysis. Which Salter-Harris classification does this represent?
Correct. Salter-Harris Type II fractures pass through the physis and exit through the metaphysis (above the physis). This is the most common physeal fracture and generally carries a good prognosis.
Salter-Harris classification: Type I — through physis only; Type II — through physis + metaphysis (most common, best prognosis); Type III — through physis + epiphysis; Type IV — through metaphysis + physis + epiphysis; Type V — crush of physis (worst prognosis). The mnemonic SALTR: Straight through, Above (metaphysis), Lower (epiphysis), Through both, Rammed/crushed.
Review the Salter-Harris classification. Type II fracture line goes through the physis AND the metaphysis — the fragment includes a metaphyseal spike (Thurston-Holland fragment). Type I is purely through the physis.
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A 72-year-old man with osteoporosis falls from standing height and sustains a fracture of the calcaneus. He reports severe hindfoot pain and inability to weight-bear. Plain radiographs reveal a Böhler's angle of 12°. What does the reduction in Böhler's angle indicate?
Correct. Böhler's angle <20° indicates flattening/compression of the posterior facet of the calcaneus, signifying a significant intra-articular fracture. CT scan is required for detailed assessment. ORIF is considered in young, active patients.
Böhler's angle (normal 20°–40°) is formed by two lines on a lateral radiograph of the calcaneus. A decreased angle (<20°) indicates compression/depression of the posterior facet (subtalar articular surface), confirming significant intra-articular calcaneal fracture. This guides surgical decision-making.
Böhler's angle of 12° is significantly below the normal range (20°–40°). This reduced angle indicates depression of the posterior subtalar facet, which is the hallmark of an intra-articular calcaneal fracture.
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A 32-year-old man sustains a femoral shaft fracture in a road traffic accident. He is haemodynamically unstable on arrival (BP 90/60 mmHg, HR 120/min). After resuscitation, which of the following is the definitive treatment of choice for the femoral shaft fracture?
Correct. After haemodynamic stabilisation (damage control phase), antegrade intramedullary interlocking nailing is the definitive treatment. It provides stable fixation with early mobilisation and has superior outcomes compared to traction or plating.
Antegrade intramedullary nailing (IMN) is the gold standard for femoral shaft fractures in adults. It allows early weight-bearing, preserves periosteal blood supply, and has low infection and non-union rates. Damage control orthopaedics (external fixator first) is used if haemodynamically unstable, followed by definitive IMN once stabilised.
Skeletal traction is only a temporary measure. Closed casting cannot maintain reduction. Immediate open plating in an unstable patient increases mortality. The correct answer is IMN after stabilisation.
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A patient sustains a high-energy injury to the midfoot in a road traffic accident. Radiograph shows lateral displacement of the second through fifth metatarsals relative to the cuneiforms, with a fracture at the base of the second metatarsal. This injury is best described as:
Correct. Lisfranc fracture-dislocation involves the tarsometatarsal complex. Lateral shift of metatarsals 2–5 with a fracture at the base of the second metatarsal (fleck sign) is pathognomonic. Missed injuries lead to chronic midfoot instability and arthritis.
Lisfranc fracture-dislocation involves disruption of the tarsometatarsal joint complex. The Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal. A fracture at the base of the second metatarsal with lateral metatarsal displacement (fleck sign) is pathognomonic. ORIF or primary arthrodesis is required.
The combination of lateral metatarsal displacement and a fracture at the base of the second metatarsal is the classic Lisfranc pattern. Jones fracture affects the proximal fifth metatarsal metaphyseal-diaphyseal junction.
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