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OR2.14-16 | Fracture Complications and Special Situations — Practice Quiz
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A 35-year-old man sustained a closed tibial shaft fracture 6 months ago treated conservatively. Repeat X-ray shows persistent fracture gap with sclerotic margins, no callus bridging, and medullary canal obliteration at the fracture ends. Clinically the site is painless and the limb is stable. What is the most likely diagnosis?
Correct. Sclerotic margins, absent callus, and obliterated medullary canal at a painless, stable site indicate atrophic non-union — caused by poor blood supply.
Atrophic non-union is characterised by sclerotic, tapered ('elephant foot' or pencil-tip) bone ends with no callus formation, often due to poor vascularity. The absence of pain and mobility indicates a non-union rather than delayed union or malunion.
Atrophic non-union is the right answer. Delayed union still shows some callus activity; hypertrophic non-union shows exuberant callus ('elephant foot') due to motion at a vascular site; malunion means the bone has healed in a deformed position.
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An orthopaedic surgeon orders investigations for a suspected infected non-union of the femur. Which combination best confirms both the presence of infection AND bone viability for planning surgical fixation?
Correct. MRI defines the extent of infection/medullary involvement; three-phase Tc-99m bone scan assesses vascularity to guide graft planning.
MRI provides superior soft tissue and medullary oedema detail indicating infection, while Tc-99m bone scan or SPECT-CT assesses bone vascularity and turnover. Together they answer both questions needed for surgical planning.
MRI + Tc-99m bone scan is the best combination for confirming infection and assessing bone vascularity simultaneously.
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A 28-year-old construction worker presents to the emergency department with a compound fracture of the tibia following a fall from scaffolding. Wound examination reveals a 4 cm laceration with moderate contamination, comminuted fracture, but the dorsalis pedis pulse is intact. How should this open fracture be classified?
Correct. Grade IIIA = wound >10 cm would be Grade III, but comminution + moderate contamination with adequate soft-tissue coverage and intact vascularity = Grade IIIA. Note: a moderately contaminated wound with comminution and no arterial injury fits IIIA.
Gustilo-Anderson classification: Grade I (<1 cm, clean), Grade II (1–10 cm, moderate contamination, no extensive soft-tissue loss), Grade IIIA (extensive soft tissue but adequate coverage), Grade IIIB (extensive soft-tissue loss requiring flap coverage), Grade IIIC (any arterial injury requiring repair). A 4 cm moderately contaminated wound with comminution but intact vascularity is Grade IIIA.
This is Grade IIIA. The comminuted fracture with moderate contamination but intact vascularity and adequate soft-tissue coverage places it in the Grade III category, subtype A.
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A 22-year-old farmer sustains an open forearm fracture in a field. He arrives at the district hospital 45 minutes after injury. Which of the following is the most critical initial antibiotic step according to current open fracture management protocols?
Correct. IV antibiotics (co-amoxiclav/cefazolin) within 1 hour of injury is the time-critical standard of care for open fractures to minimise deep infection risk.
IV antibiotics (co-amoxiclav or cefazolin) must be started within 1 hour of injury for open fractures. Delayed antibiotic administration significantly increases infection risk. Tetanus prophylaxis is also mandatory but antibiotics within 1 h is the highest-priority time-critical step.
The key known trap: antibiotics must be given within 1 hour of the open fracture — NOT delayed until theatre or culture results.
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A 7-year-old boy falls on his outstretched hand and presents with pain, swelling, and deformity around the elbow. X-ray shows a supracondylar fracture of the humerus with posterior displacement. On examination, the child cannot flex the interphalangeal joint of the index finger or extend the thumb at the interphalangeal joint, but grip strength is preserved. Which nerve is most likely injured?
Correct. AIN injury causes loss of FDP to index and FPL (thumb), no sensory loss — the 'OK sign' cannot be made. AIN is the most commonly injured nerve in supracondylar fractures.
The anterior interosseous nerve (AIN), a purely motor branch of the median nerve, is the most commonly injured nerve in supracondylar fractures. Its deficit manifests as inability to flex the IP joint of the index finger (FDP) and the IP joint of the thumb (FPL), producing the classic 'OK sign failure' (pinch grip affected). Sensation is spared.
AIN (a branch of the median nerve) is the most commonly injured nerve in supracondylar fractures. Its purely motor nature explains absent sensory loss.
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A 5-year-old child is brought with inability to use the right arm after a caretaker pulled the child up by the hand to prevent a fall. The child holds the arm adducted, internally rotated, and slightly pronated. There is no bony tenderness; X-rays are normal. What is the most appropriate management?
Correct. Pulled elbow is managed by closed reduction — supination then flexion (or hyperpronation). A palpable/audible click confirms reduction; the child resumes normal arm use within minutes.
Pulled elbow (nursemaid's elbow / radial head subluxation) occurs from sudden traction on a pronated extended forearm in children under 6. The annular ligament slips over the radial head. Closed reduction by full supination + flexion (or hyperpronation) is the treatment — no imaging needed if the history is classic, and reduction is immediate.
This is pulled elbow (nursemaid's elbow). The definitive treatment is closed reduction by supination-flexion or hyperpronation — no surgery needed.
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A 10-year-old girl falls off a bicycle and injures her right wrist. X-ray reveals a fracture through the physis with separation of the epiphysis; the metaphysis is intact and there is no metaphyseal fragment. This fracture is correctly classified as which Salter-Harris type?
Correct. A pure physeal separation with no bony fragment = Salter-Harris Type I. It has the best prognosis for growth.
Salter-Harris classification: Type I = through physis only (separation); Type II = through physis + metaphyseal fragment (most common); Type III = through physis + epiphysis; Type IV = through metaphysis, physis, and epiphysis; Type V = crush of physis. Type I is a pure physeal separation with no metaphyseal fragment.
Salter-Harris Type I is a pure physeal separation. Type II includes a metaphyseal fragment (Thurston-Holland sign); Type III involves the epiphysis; Type IV crosses metaphysis, physis, and epiphysis.
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A 14-year-old boy sustained a tibial fracture 4 months ago treated with a cast. He now presents with a shortened limb and external rotation deformity. X-ray shows the fracture has healed with 15° angulation and 1 cm shortening. The patient has minimal pain. What is the correct diagnosis?
Correct. Malunion = fracture healed in a deformed position (angulation, rotation, or shortening). The bone is united but in the wrong alignment.
Malunion is defined as a fracture that has healed in an unsatisfactory position — with angulation, rotation, or shortening. Union has occurred (hence no pain/instability), but alignment is abnormal. This is different from non-union (failure to heal) or delayed union (slow healing).
Malunion is the right answer. The fracture has healed (no pain/instability) but in a deformed position with angulation and shortening.
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