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ABOS Orthopaedic Surgery study materials
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ABOS Orthopaedic Surgery practice questions

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Question 1Part I (Written Examination)

A 24-year-old man sustains a closed tibial shaft fracture. Which finding most strongly indicates an impending compartment syndrome?

  1. Palpable dorsalis pedis pulse
  2. Diffuse swelling of the calf without tenseness
  3. Paresthesia that resolves with elevation of the limb
  4. Pain with passive stretch of the toes that is out of proportion to the injury Correct answer.

Explanation

Compartment syndrome is a clinical diagnosis in which pain, especially with passive stretch of the muscles in the involved compartment, is the earliest and most reliable finding. Pulses are typically preserved because the process is driven by increased tissue pressure rather than arterial occlusion. Sensory changes may occur but do not resolve simply with elevation.

Question 2Part I (Written Examination)

Which nerve is most commonly injured during a direct lateral approach to the hip?

  1. Superior gluteal nerve Correct answer.
  2. Obturator nerve
  3. Sciatic nerve
  4. Femoral nerve

Explanation

The direct lateral (Hardinge) approach splits the gluteus medius and minimus near the greater trochanter, placing the superior gluteal nerve and its branches at risk. Injury can produce a Trendelenburg gait from abductor weakness. The other nerves listed are not the principal concern with this exposure.

Question 3Part I (Written Examination)

A 62-year-old woman has a distal radius fracture with dorsal comminution and dorsal angulation. Which eponym describes this deformity pattern?

  1. Chauffeur fracture
  2. Colles fracture Correct answer.
  3. Smith fracture
  4. Barton fracture

Explanation

A Colles fracture is a distal radius fracture with dorsal angulation and dorsal displacement, often with dorsal comminution. Smith fractures have volar displacement, Barton fractures involve the articular rim, and chauffeur fractures involve the radial styloid.

Question 4Part I (Written Examination)

In an adult, which parameter is used to define the mechanical axis of the lower limb on a full-length standing radiograph?

  1. Line from the greater trochanter to the lateral malleolus
  2. Line along the anterior cortex of the femur
  3. Line from the center of the femoral head to the center of the ankle Correct answer.
  4. Line from the anterior superior iliac spine to the patella

Explanation

The mechanical axis is drawn from the center of the femoral head to the center of the ankle joint and should pass near the center of the knee in normal alignment. The anatomic axis follows the femoral shaft and differs by roughly 5 to 7 degrees. The other described lines are not standard definitions of the mechanical axis.

Question 5Part I (Written Examination)

A 7-year-old child has a lateral physeal fracture of the distal humerus with the metaphyseal fragment attached to the epiphysis. Which Salter-Harris type is this?

  1. Type II Correct answer.
  2. Type I
  3. Type IV
  4. Type III

Explanation

A Salter-Harris type II fracture passes through the physis and exits through the metaphysis, carrying a metaphyseal fragment (Thurston-Holland fragment) with the epiphysis. Type III exits through the epiphysis, and type IV crosses both metaphysis and epiphysis. Type I involves the physis alone.

Question 6Part I (Written Examination)

A patient has a displaced femoral neck fracture with disruption of the medial femoral circumflex artery. Which complication is most directly attributable to this vascular injury?

  1. Sciatic nerve palsy
  2. Heterotopic ossification
  3. Trochanteric bursitis
  4. Avascular necrosis of the femoral head Correct answer.

Explanation

The medial femoral circumflex artery is the principal blood supply to the femoral head through the retinacular vessels, so disruption can cause avascular necrosis. Heterotopic ossification, nerve palsy, and bursitis are unrelated to this specific vascular territory.

Question 7Part I (Written Examination)

Which organism is the most common cause of septic arthritis in a sexually active young adult?

  1. Neisseria gonorrhoeae Correct answer.
  2. Streptococcus pneumoniae
  3. Staphylococcus aureus
  4. Pseudomonas aeruginosa

Explanation

Neisseria gonorrhoeae is the leading cause of septic arthritis in sexually active young adults, though Staphylococcus aureus remains the most common cause overall across all age groups. Pseudomonas is associated with intravenous drug use, and pneumococcus is less typical in this population.

Question 8Part I (Written Examination)

A 45-year-old man has chronic, dull buttock pain that worsens with sitting and is relieved by standing. Examination shows pain with resisted external rotation and abduction. Which diagnosis is most likely?

  1. Piriformis syndrome Correct answer.
  2. Ankylosing spondylitis
  3. Lumbar disc herniation
  4. Greater trochanteric pain syndrome

Explanation

Piriformis syndrome produces deep buttock pain aggravated by sitting and by resisted external rotation and abduction, reflecting irritation of the sciatic nerve by the piriformis. Lumbar disc herniation typically causes radicular pain with positive straight-leg raise, and greater trochanteric pain syndrome is tender over the trochanter.

Question 9Part I (Written Examination)

Which finding on magnetic resonance imaging is most characteristic of an acute osteomyelitis in the vertebral body?

  1. Uniform low signal on all sequences
  2. Normal marrow signal with cortical thickening
  3. Increased T1 signal and decreased T2 signal without enhancement
  4. Decreased T1 signal and increased T2 signal with enhancement Correct answer.

Explanation

Acute vertebral osteomyelitis typically shows marrow edema with low T1 and high T2 signal and post-contrast enhancement, often with adjacent disc involvement. Increased T1 signal is more typical of fat or hemorrhage, and normal marrow signal does not suggest acute infection.

Question 10Part I (Written Examination)

A 30-year-old woman has a 6-month history of anterior knee pain that worsens with stairs and prolonged sitting. Examination shows pain with patellar compression and no effusion. Which diagnosis is most likely?

  1. Anterior cruciate ligament tear
  2. Pes anserine bursitis
  3. Meniscal tear
  4. Patellofemoral pain syndrome Correct answer.

Explanation

Patellofemoral pain syndrome causes anterior knee pain worsened by loading the patellofemoral joint, such as stairs and prolonged sitting, with patellar compression tenderness and typically no effusion. Meniscal and ligamentous injuries usually produce mechanical symptoms or instability, and pes anserine bursitis causes medial knee pain.

Question 11Part I (Written Examination)

Which radiographic view best demonstrates the presence of a posterior shoulder dislocation?

  1. Zanca view
  2. Stryker notch view
  3. Axillary or scapular Y view Correct answer.
  4. Anteroposterior view in internal rotation

Explanation

Posterior dislocations are easily missed on a standard AP view because the humeral head may appear normally aligned; the axillary or scapular Y view directly shows the abnormal relationship. The Zanca view assesses the acromioclavicular joint, and the Stryker notch view assesses the humeral head for a Hill-Sachs lesion.

Question 12Part I (Written Examination)

A 68-year-old man has a lytic lesion in the proximal femur with cortical destruction. Which feature most increases the risk of pathologic fracture?

  1. Presence of a sclerotic rim
  2. Lesion size greater than 2.5 cm with cortical involvement Correct answer.
  3. Slow growth over several years
  4. Location in the medullary canal

Explanation

Pathologic fracture risk rises with larger lesion size, cortical destruction, and lesions in weight-bearing regions, often estimated using Mirels criteria. A sclerotic rim and slow growth suggest a benign, less aggressive process. Medullary location alone is not a strong predictor.

Question 13Part I (Written Examination)

Which muscle is the primary dynamic stabilizer preventing anterior translation of the humeral head in the throwing shoulder?

  1. Teres minor
  2. Supraspinatus
  3. Infraspinatus
  4. Subscapularis Correct answer.

Explanation

The subscapularis is the anterior rotator cuff muscle and functions as the primary dynamic restraint against anterior humeral head translation. The infraspinatus and teres minor are posterior stabilizers, and the supraspinatus primarily elevates the arm.

Question 14Part I (Written Examination)

A patient sustains a direct blow to the anterior thigh with a large, tense hematoma and rapidly rising compartment pressures. Which compartment is most commonly involved?

  1. Medial compartment
  2. Anterior compartment Correct answer.
  3. Deep posterior compartment
  4. Posterior compartment

Explanation

The anterior compartment of the thigh is the most frequently involved in thigh compartment syndrome, often after direct trauma or anticoagulation-related bleeding. It contains the quadriceps and femoral nerve, and elevated pressure can cause pain and weakness.

Question 15Part I (Written Examination)

Which laboratory finding is most consistent with a diagnosis of gout during an acute flare?

  1. Gram-positive cocci on joint aspirate
  2. Elevated serum uric acid level alone
  3. Positively birefringent rhomboid crystals
  4. Negatively birefringent needle-shaped crystals Correct answer.

Explanation

Gout is confirmed by needle-shaped, negatively birefringent monosodium urate crystals on polarized microscopy. Pseudogout shows positively birefringent rhomboid calcium pyrophosphate crystals. Serum uric acid may be normal during an acute flare, and bacteria indicate septic arthritis.

Question 16Part I (Written Examination)

A 55-year-old woman has a displaced distal humerus fracture with a pale, pulseless hand. Which initial step is most appropriate?

  1. Immediate closed reduction and splinting with reassessment of vascular status Correct answer.
  2. Application of a compressive bandage and observation
  3. Elective open reduction after swelling subsides
  4. Aspiration of the elbow joint

Explanation

A pulseless limb after fracture signals vascular compromise, and urgent reduction and stabilization to restore alignment and perfusion is the priority, followed by reassessment and vascular surgery consultation if perfusion does not return. Observation or delay risks ischemic loss.

Question 17Part I (Written Examination)

Which structure is most at risk during placement of a proximal interlocking screw in an antegrade femoral nail?

  1. Femoral artery
  2. Sciatic nerve
  3. Lateral femoral cutaneous nerve Correct answer.
  4. Saphenous nerve

Explanation

The lateral femoral cutaneous nerve courses near the anterior superior iliac spine and proximal lateral thigh and can be injured during proximal interlocking screw placement. The femoral artery, saphenous nerve, and sciatic nerve are not typically at risk at that site.

Question 18Part I (Written Examination)

A 10-year-old boy has a slipped capital femoral epiphysis. Which radiographic finding is most characteristic?

  1. Lucent lesion in the femoral neck
  2. Narrowed joint space with osteophytes
  3. Widened physis with medial displacement of the femoral head Correct answer.
  4. Coxa magna with a normal physis

Explanation

Slipped capital femoral epiphysis shows displacement of the femoral head relative to the neck through a widened physis, often with the head slipping posteriorly and medially. Osteophytes and joint space narrowing suggest osteoarthritis, and coxa magna is a different process.

Question 19Part I (Written Examination)

Which tendon is most commonly affected in de Quervain tenosynovitis?

  1. Extensor carpi radialis brevis and longus
  2. Extensor pollicis brevis and abductor pollicis longus Correct answer.
  3. Flexor carpi radialis and flexor pollicis longus
  4. Flexor digitorum superficialis and profundus

Explanation

De Quervain tenosynovitis involves the first dorsal compartment, containing the abductor pollicis longus and extensor pollicis brevis tendons. It causes radial-sided wrist pain and a positive Finkelstein test. The other tendon groups subserve different functions and compartments.

Question 20Part I (Written Examination)

A patient has a complete radial nerve palsy after a humeral shaft fracture with an associated wrist drop. Which finding is expected on examination?

  1. Inability to extend the wrist and fingers Correct answer.
  2. Inability to flex the elbow
  3. Loss of finger abduction
  4. Loss of thumb opposition

Explanation

The radial nerve supplies the wrist and finger extensors, so injury produces wrist drop and impaired finger extension. Elbow flexion is mediated by the musculocutaneous nerve, thumb opposition by the median nerve, and finger abduction by the ulnar nerve.

Question 21Part I (Written Examination)

Which of the following best describes the role of the anterior cruciate ligament in knee biomechanics?

  1. Restraining anterior tibial translation and rotational laxity Correct answer.
  2. Restraining posterior tibial translation
  3. Restraining terminal knee extension
  4. Restraining valgus stress in extension

Explanation

The anterior cruciate ligament limits anterior translation of the tibia relative to the femur and contributes to rotational stability. Posterior translation is restrained by the posterior cruciate ligament, valgus stress by the medial collateral ligament, and terminal extension by the posterior capsule.

Question 22Part I (Written Examination)

A 70-year-old woman has a fragility fracture of the distal radius. Which underlying condition most commonly predisposes to this injury?

  1. Osteopetrosis
  2. Osteoporosis Correct answer.
  3. Fibrous dysplasia
  4. Paget disease

Explanation

Osteoporosis reduces bone mineral density and is the most common predisposing factor for fragility fractures in older adults, including distal radius fractures. Paget disease, fibrous dysplasia, and osteopetrosis are less common and have distinct radiographic features.

Question 23Part I (Written Examination)

A 40-year-old man has a locked knee that cannot fully extend after a twisting injury. Which structure is most likely interposed?

  1. Posterior cruciate ligament
  2. Medial meniscus Correct answer.
  3. Iliotibial band
  4. Patellar tendon

Explanation

A displaced meniscal tear, most often of the medial meniscus, can displace into the joint and block extension, producing a locked knee. The posterior cruciate ligament, iliotibial band, and patellar tendon do not typically cause a true mechanical block of this kind.

Question 24Part I (Written Examination)

Which factor most increases the risk of nonunion after a long bone fracture?

  1. Anatomic reduction with compression
  2. Adequate fracture stability with early weight bearing
  3. Open fracture with soft tissue stripping Correct answer.
  4. Young patient age

Explanation

Open fractures with extensive soft tissue stripping compromise the blood supply and healing environment, increasing nonunion risk. Adequate stability, young age, and anatomic reduction with compression favor union.

Question 25Part I (Written Examination)

Which imaging modality is most sensitive for detecting an occult scaphoid fracture at presentation?

  1. Magnetic resonance imaging Correct answer.
  2. Ultrasonography
  3. Plain radiography
  4. Computed tomography

Explanation

Magnetic resonance imaging is the most sensitive study for occult scaphoid fractures because it detects marrow edema and the fracture line early. Plain radiographs can be normal initially, and CT or ultrasound are less sensitive for acute occult injury.

Question 26Part I (Written Examination)

A 22-year-old football player sustains a direct blow to the lateral knee, resulting in a valgus stress. Which structure is most likely injured?

  1. Posterior cruciate ligament
  2. Medial collateral ligament Correct answer.
  3. Lateral collateral ligament
  4. Anterior cruciate ligament

Explanation

A valgus force applied to the knee stresses the medial side, causing injury to the medial collateral ligament. The lateral collateral ligament is injured by varus stress, and the cruciate ligaments are primarily injured by rotational or translational forces.

Question 27Part I (Written Examination)

A 65-year-old woman sustains a Colles fracture after a fall on an outstretched hand. Which deformity is most characteristic of this fracture?

  1. Volkmann contracture
  2. Galeazzi sign
  3. Dinner fork deformity Correct answer.
  4. Clunk test

Explanation

A Colles fracture is a distal radius fracture with dorsal displacement and angulation, producing a dinner fork deformity. A Galeazzi fracture involves the distal radius with disruption of the distal radioulnar joint, and Volkmann contracture is a complication of compartment syndrome.

Question 28Part I (Written Examination)

A 45-year-old man presents with a swollen, painful knee. Arthrocentesis yields cloudy fluid with a white blood cell count of 75,000 cells/mm³ with 90% neutrophils. Which is the most likely diagnosis?

  1. Gout
  2. Septic arthritis Correct answer.
  3. Rheumatoid arthritis
  4. Osteoarthritis

Explanation

Septic arthritis typically presents with synovial fluid leukocyte counts greater than 50,000 cells/mm³ with a predominance of neutrophils. Gout and rheumatoid arthritis usually have lower cell counts, and osteoarthritis is noninflammatory with a low cell count.

Question 29Part I (Written Examination)

A 30-year-old man sustains a humeral shaft fracture. Two weeks later, he presents with a wrist drop and decreased sensation over the dorsum of the first web space. Which nerve is most likely injured?

  1. Median nerve
  2. Axillary nerve
  3. Radial nerve Correct answer.
  4. Ulnar nerve

Explanation

The radial nerve runs in the spiral groove of the humerus and is at risk with humeral shaft fractures. Injury causes wrist drop and sensory loss over the dorsal first web space. The median and ulnar nerves are not typically injured in humeral shaft fractures, and the axillary nerve is at risk with proximal humerus fractures or shoulder dislocations.

Question 30Part I (Written Examination)

A 55-year-old woman has a distal radius fracture and is treated with a cast. Six hours later, she has severe pain with passive stretch of the fingers and paresthesias. Which is the most appropriate next step?

  1. Elevation and ice
  2. Oral analgesics
  3. Emergent fasciotomy Correct answer.
  4. Repeat casting

Explanation

The clinical picture is consistent with acute compartment syndrome, which is a surgical emergency. Emergent fasciotomy is required to prevent irreversible muscle and nerve damage. Elevation, recasting, and analgesics are not definitive treatments and may delay necessary surgery.

Question 31Part I (Written Examination)

Which is the most common site of a stress fracture in a runner?

  1. First metatarsal
  2. Tibia Correct answer.
  3. Calcaneus
  4. Femur

Explanation

The tibia is the most common site of stress fractures in runners, followed by the metatarsals and fibula. The femur and calcaneus are less common sites.

Question 32Part I (Written Examination)

Which is the most common direction of shoulder dislocation?

  1. Inferior
  2. Superior
  3. Anterior Correct answer.
  4. Posterior

Explanation

Anterior shoulder dislocation accounts for approximately 95% of shoulder dislocations. Posterior dislocations are less common and often associated with seizures or electrical shocks. Inferior and superior dislocations are rare.

Question 33Part I (Written Examination)

A 60-year-old man has a displaced femoral neck fracture. Which complication is most likely if the blood supply to the femoral head is disrupted?

  1. Osteomyelitis
  2. Avascular necrosis Correct answer.
  3. Malunion
  4. Nonunion

Explanation

The blood supply to the femoral head is primarily from the medial femoral circumflex artery. Disruption leads to avascular necrosis. Nonunion and malunion can occur but are not directly related to blood supply disruption. Osteomyelitis is an infection and not a direct result of vascular compromise.

Question 34Part I (Written Examination)

A 25-year-old man sustains a knee injury with a pop and immediate swelling. The Lachman test is positive. Which structure is most likely torn?

  1. Lateral meniscus
  2. Medial collateral ligament
  3. Anterior cruciate ligament Correct answer.
  4. Posterior cruciate ligament

Explanation

A positive Lachman test indicates anterior cruciate ligament (ACL) insufficiency. The ACL is the primary restraint to anterior tibial translation. A pop with immediate swelling (hemarthrosis) is classic for an ACL tear.

Question 35Part I (Written Examination)

A 45-year-old woman has a distal radius fracture treated with cast immobilization. Which radiographic parameter is most important to restore to prevent functional impairment?

  1. Scapholunate angle
  2. Ulnar variance
  3. Carpal height
  4. Radial inclination Correct answer.

Explanation

Radial inclination is a key parameter in distal radius fractures; restoration improves wrist function and reduces the risk of instability. Ulnar variance, carpal height, and scapholunate angle are important but less directly related to the outcomes of distal radius fracture treatment.

Question 36Part I (Written Examination)

A 12-year-old boy has a slipped capital femoral epiphysis (SCFE). Which radiographic finding is most characteristic?

  1. Widened physis
  2. Coxa magna
  3. Tomographic sign
  4. Decreased epiphyseal height Correct answer.

Explanation

In SCFE, the femoral head slips posteriorly and inferiorly, leading to a decreased epiphyseal height on the AP radiograph (the 'blanch sign' or decreased height of the epiphysis). A widened physis may be seen but is less specific. Coxa magna is enlargement of the femoral head, and the tomographic sign is not a standard radiographic finding.

Question 37Part I (Written Examination)

A 55-year-old man has a displaced tibial plateau fracture. Which associated injury should be suspected?

  1. Patellar tendon rupture
  2. Anterior cruciate ligament tear
  3. Compartment syndrome Correct answer.
  4. Meniscal tear

Explanation

Tibial plateau fractures are high-energy injuries that can cause significant swelling and are associated with compartment syndrome. While ligament and meniscal injuries can occur, compartment syndrome is a limb-threatening complication that must be suspected.

Question 38Part I (Written Examination)

A 60-year-old woman has a distal humerus fracture with a pale, pulseless hand. Which artery is most likely injured?

  1. Ulnar artery
  2. Axillary artery
  3. Brachial artery Correct answer.
  4. Radial artery

Explanation

The brachial artery runs anterior to the distal humerus and is at risk in supracondylar fractures. Injury can lead to a pale, pulseless hand. The radial and ulnar arteries are further distal, and the axillary artery is more proximal.

Question 39Part I (Written Examination)

A 35-year-old man has chronic patellar tendinopathy. Which activity is most likely to exacerbate his symptoms?

  1. Rowing
  2. Cycling
  3. Jumping Correct answer.
  4. Swimming

Explanation

Patellar tendinopathy (jumper's knee) is common in athletes who perform repetitive jumping, which loads the patellar tendon. Cycling, swimming, and rowing are less likely to provoke symptoms.

Question 40Part I (Written Examination)

A 28-year-old woman has a 6-month history of anterior knee pain that worsens with stairs and prolonged sitting. Examination reveals tenderness over the medial patellar facet and a positive patellar grind test. Which is the most likely diagnosis?

  1. Patellofemoral pain syndrome Correct answer.
  2. Patellar tendinopathy
  3. Meniscal tear
  4. Iliotibial band syndrome

Explanation

Patellofemoral pain syndrome typically presents with anterior knee pain exacerbated by activities that increase patellofemoral joint stress, such as stairs and sitting. Tenderness over the medial patellar facet and a positive grind test support this diagnosis. Patellar tendinopathy causes pain at the inferior pole of the patella, meniscal tears cause joint line tenderness, and IT band syndrome causes lateral knee pain.

Question 41Part I (Written Examination)

A 70-year-old man has a hip fracture and is scheduled for surgery. Which factor most increases his risk of perioperative complications?

  1. Early mobilization
  2. Preoperative antibiotics
  3. Use of regional anesthesia
  4. Delay in surgery beyond 48 hours Correct answer.

Explanation

Delay in hip fracture surgery beyond 48 hours is associated with increased morbidity and mortality. Regional anesthesia, early mobilization, and preoperative antibiotics are strategies that reduce complications.

Question 42Part I (Written Examination)

A 50-year-old man has a complete Achilles tendon rupture. Which physical examination finding is most specific?

  1. Positive Thompson test Correct answer.
  2. Positive Phalen test
  3. Positive McMurray test
  4. Positive Lachman test

Explanation

The Thompson test is specific for Achilles tendon rupture; squeezing the calf fails to produce plantarflexion. The McMurray test assesses meniscal tears, the Lachman test assesses the ACL, and the Phalen test assesses carpal tunnel syndrome.

Question 43Part I (Written Examination)

A 65-year-old woman has a distal radius fracture with dorsal comminution. Which treatment is most appropriate?

  1. Volar locking plate fixation Correct answer.
  2. Closed reduction and pinning
  3. External fixation
  4. Below-elbow cast

Explanation

Volar locking plate fixation provides stable fixation for dorsally comminuted distal radius fractures, allowing early mobilization. Casting may not maintain reduction in comminuted fractures. External fixation and pinning are options but are less commonly used for this specific pattern.

Question 44Part I (Written Examination)

A 30-year-old man has a displaced scaphoid fracture. Which factor most increases the risk of nonunion?

  1. Nondisplaced fracture
  2. Tuberosity fracture
  3. Proximal pole fracture Correct answer.
  4. Distal pole fracture

Explanation

Proximal pole scaphoid fractures have a retrograde blood supply and are at higher risk of nonunion and avascular necrosis. Distal pole and tuberosity fractures have a better blood supply and lower risk of nonunion. Nondisplaced fractures also have a lower risk of nonunion.

Question 45Part I (Written Examination)

A 55-year-old woman has a distal radius fracture and undergoes open reduction and internal fixation. Which postoperative complication is most common?

  1. Infection
  2. Hardware irritation Correct answer.
  3. Nonunion
  4. Malunion

Explanation

Hardware irritation is a common complication after volar plating for distal radius fractures, often requiring hardware removal. Nonunion, malunion, and infection can occur but are less common.

Question 46Part I (Written Examination)

A 60-year-old man has a tibial shaft fracture treated with an intramedullary nail. Which structure is most at risk during proximal interlocking screw placement?

  1. Posterior tibial artery
  2. Saphenous nerve
  3. Peroneal nerve
  4. Anterior tibial artery Correct answer.

Explanation

The anterior tibial artery passes through the interosseous membrane and is at risk during proximal interlocking screw placement. The peroneal nerve is at risk with proximal fibular fractures, the saphenous nerve is at risk with medial ankle incisions, and the posterior tibial artery is at risk with posterior tibial plateau fractures.

Question 47Part I (Written Examination)

A 45-year-old man has a distal humerus fracture with a pulseless hand after reduction. Which is the most appropriate next step?

  1. Observation for 24 hours
  2. Immediate vascular exploration Correct answer.
  3. Repeat closed reduction
  4. Angiography

Explanation

A pulseless hand after reduction of a distal humerus fracture suggests vascular injury, likely brachial artery. Immediate vascular exploration is indicated to restore perfusion and prevent limb loss. Observation, repeat reduction, and angiography may delay definitive treatment.

Question 48Part I (Written Examination)

A 70-year-old woman has a distal radius fracture and is treated with a cast. Three months later, she has a stiff, painful wrist. Radiographs show healing in dorsiflexion. Which complication has occurred?

  1. Complex regional pain syndrome
  2. Infection
  3. Malunion Correct answer.
  4. Nonunion

Explanation

Malunion is healing in a nonanatomic position, which can lead to pain and stiffness. Nonunion is failure of healing, infection would show signs of inflammation, and complex regional pain syndrome is a pain syndrome without radiographic malalignment.

Question 49Part I (Written Examination)

A 25-year-old man has a posterior shoulder dislocation after a seizure. Which radiographic view is most useful for diagnosis?

  1. Anteroposterior view
  2. Stryker notch view
  3. Axillary lateral view Correct answer.
  4. Scapular Y view

Explanation

The axillary lateral view is most useful for diagnosing posterior shoulder dislocation, as it clearly shows the posterior displacement of the humeral head. The AP view may appear normal or show the 'lightbulb' sign. The scapular Y view and Stryker notch view are adjuncts but less sensitive.

Question 50Part I (Written Examination)

A 45-year-old man sustains a closed tibial shaft fracture after a motorcycle accident. He is neurovascularly intact. Which of the following is the most appropriate initial management?

  1. Long leg cast with immediate weight-bearing
  2. Open reduction and internal fixation with plates and screws
  3. Skeletal traction for 6 weeks
  4. Intramedullary nailing Correct answer.

Explanation

Intramedullary nailing is the treatment of choice for most displaced tibial shaft fractures in adults because it provides stable fixation with early mobilization and high union rates. Casting and traction are associated with higher rates of malunion and stiffness. Plating is generally reserved for specific indications such as periarticular extension or failed nailing.