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2. Trauma MCQs

Practice Set 366 of 640

This practice set contains high-yield board review questions covering key concepts in 2. Trauma. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 7301

Topic: 2. Trauma

When performing open reduction and internal fixation (ORIF) of a 2-part surgical neck fracture of the proximal humerus, placement of a screw into the inferomedial quadrant of the humeral head (calcar screw) is primarily intended to:

. Prevent anterior translation of the humeral head
. Prevent varus collapse of the humeral head
. Prevent avascular necrosis of the humeral head
. Avoid impingement of the greater tuberosity
. Provide dynamic compression across the fracture site

Correct Answer & Explanation

. Prevent anterior translation of the humeral head

Explanation

The inferomedial "calcar" screws in locking plate constructs for proximal humerus fractures provide critical medial column support. This significantly reduces the risk of postoperative varus collapse.

Question 7302

Topic: 2. Trauma

A 65-year-old patient underwent a hemiarthroplasty for a complex 4-part proximal humerus fracture. Postoperatively, radiographs show that the greater tuberosity has migrated superiorly and healed in a malunited position. This complication is most likely to result in:

. Axillary nerve palsy
. Subacromial impingement and secondary cuff dysfunction
. Glenoid component loosening
. Anterior instability
. Heterotopic ossification

Correct Answer & Explanation

. Axillary nerve palsy

Explanation

Tuberosity malposition, particularly superior migration, is a leading cause of failure after hemiarthroplasty for proximal humerus fractures. Superior malunion leads to severe subacromial impingement, blocking active elevation and causing profound rotator cuff dysfunction.

Question 7303

Topic: 2. Trauma

A 65-year-old female presents with a 4-part proximal humerus fracture.

According to the Hertel criteria, which radiographic feature is most predictive of humeral head ischemia?

. Greater tuberosity displacement > 5 mm
. Calcar segment attached to the articular surface of < 8 mm
. Metaphyseal head extension > 20 mm
. An intact medial hinge
. Shaft displacement > 50%

Correct Answer & Explanation

. Greater tuberosity displacement > 5 mm

Explanation

Hertel identified specific predictors of humeral head ischemia, the strongest of which are a short calcar segment (<8 mm), a disrupted medial hinge, and an anatomic neck fracture pattern.

Question 7304

Topic: 2. Trauma

A 75-year-old woman sustains a minimally displaced 2-part surgical neck fracture of the proximal humerus. She is treated nonoperatively in a sling. To optimize functional outcomes and prevent adhesive capsulitis, when should gentle pendulum exercises and passive range of motion begin?

. Immediately, on the day of injury
. Within 1 to 2 weeks post-injury
. At 4 weeks post-injury
. At 6 weeks, after radiographic union is visible
. At 8 weeks post-injury

Correct Answer & Explanation

. Immediately, on the day of injury

Explanation

For minimally displaced proximal humerus fractures treated nonoperatively, early progressive motion (pendulums/passive ROM) should ideally begin within 7-14 days to prevent severe post-traumatic shoulder stiffness.

Question 7305

Topic: 2. Trauma

A 72-year-old female undergoes open reduction and internal fixation with a locking plate for a displaced 3-part proximal humerus fracture. Osteoporotic bone is noted during surgery. What is the most common hardware-related complication postoperatively?

. Plate breakage
. Intra-articular screw penetration (screw cut-out)
. Axillary nerve entrapment by the plate
. Nonunion of the greater tuberosity
. Infection

Correct Answer & Explanation

. Plate breakage

Explanation

In the setting of osteoporotic proximal humerus fractures fixed with a locking plate, the most common hardware complication is intra-articular screw penetration. This typically occurs as the fracture settles or collapses, causing the fixed-angle screws to protrude into the joint.

Question 7306

Topic: 2. Trauma

A 65-year-old female sustains a proximal humerus fracture after a mechanical fall. According to Hertel's criteria, which of the following radiographic findings is the most reliable predictor of humeral head ischemia?

. Metaphyseal head extension > 8 mm
. Intact medial hinge
. Disruption of the medial hinge
. Valgus impaction
. Greater tuberosity displacement > 5 mm

Correct Answer & Explanation

. Metaphyseal head extension > 8 mm

Explanation

Hertel's criteria for predicting humeral head ischemia include a disrupted medial hinge, short calcar length (metaphyseal extension < 8 mm), and basicervical/anatomic neck fracture patterns. An intact medial hinge and valgus impaction are protective of the blood supply.

Question 7307

Topic: 2. Trauma

When performing a reverse total shoulder arthroplasty for a 4-part proximal humerus fracture in an elderly patient, anatomic healing of the greater tuberosity to the proximal humerus shaft is most critical for restoring which of the following active motions?

. Forward elevation
. Internal rotation
. External rotation
. Abduction
. Extension

Correct Answer & Explanation

. Forward elevation

Explanation

In RTSA for proximal humerus fractures, healing of the greater tuberosity (containing the infraspinatus and teres minor insertions) is strongly correlated with improved active external rotation and overall functional outcomes.

Question 7308

Topic: 2. Trauma

A 62-year-old woman undergoes open reduction and internal fixation with a locked plate for a 3-part proximal humerus fracture.

Which of the following is the most common complication associated with this specific procedure?

. Avascular necrosis of the humeral head
. Intra-articular screw penetration
. Axillary nerve palsy
. Symptomatic nonunion
. Deep surgical site infection

Correct Answer & Explanation

. Avascular necrosis of the humeral head

Explanation

Intra-articular screw penetration is the most frequent complication following locked plating of proximal humerus fractures. This often occurs secondary to fracture settling or varus collapse over rigid fixed-angle screws.

Question 7309

Topic: 2. Trauma

A 65-year-old woman sustains a 3-part proximal humerus fracture. According to Hertel's criteria, which of the following radiographic findings is most strongly predictive of humeral head ischemia?

. Metaphyseal head extension >8mm
. Disruption of the medial hinge >2mm
. Angulation of the head >45 degrees
. Greater tuberosity displacement >5mm
. An intact medial calcar

Correct Answer & Explanation

. Metaphyseal head extension >8mm

Explanation

Hertel's criteria for high risk of humeral head ischemia include a posteromedial metaphyseal head extension <8 mm, disruption of the medial hinge >2 mm, and an anatomic neck fracture pattern. Disruption of the medial hinge removes the critical blood supply from the ascending branch of the anterior circumflex humeral artery.

Question 7310

Topic: 2. Trauma

A 55-year-old woman undergoes locking plate osteosynthesis for a 4-part proximal humerus fracture. Six months later, she presents with severe pain and a mechanical block to motion. Radiographs show fracture healing but the superior-most locking screws are protruding through the articular surface. What intraoperative step is most critical to prevent this complication?

. Use of a deltopectoral approach rather than anterolateral
. Placement of an inferomedial calcar screw
. Ensuring screws are 10mm shorter than the subchondral bone
. Use of non-locking screws proximally
. Routine use of structural bone graft

Correct Answer & Explanation

. Use of a deltopectoral approach rather than anterolateral

Explanation

Primary varus collapse of the humeral head is the most common reason for secondary screw cutout in proximal humerus plating. An inferomedial calcar screw provides structural support to resist this varus displacement.

Question 7311

Topic: 2. Trauma

In the treatment of a comminuted 4-part proximal humerus fracture with a reverse total shoulder arthroplasty, anatomic healing of the greater tuberosity is most strongly associated with which functional outcome?

. Improved active forward elevation
. Decreased risk of acromial stress fracture
. Improved active external rotation
. Prevention of scapular notching
. Increased strength in internal rotation

Correct Answer & Explanation

. Improved active forward elevation

Explanation

In RSA for proximal humerus fractures, healing of the greater tuberosity (which houses the infraspinatus and teres minor attachments) is critical for restoring active external rotation and maximizing overall functional outcomes.

Question 7312

Topic: 2. Trauma

A 65-year-old female sustains a comminuted 4-part proximal humerus fracture. Which of the following radiographic findings is most predictive of avascular necrosis of the humeral head?

. Posteromedial metaphyseal head extension less than 8 mm
. Displacement of the greater tuberosity greater than 5 mm
. Angulation of the surgical neck greater than 45 degrees
. Disruption of the anterior circumflex humeral artery
. Impaction of the articular surface

Correct Answer & Explanation

. Posteromedial metaphyseal head extension less than 8 mm

Explanation

Hertel's radiographic criteria for predicting humeral head ischemia include a posteromedial metaphyseal extension of less than 8 mm and disruption of the medial hinge greater than 2 mm.

Question 7313

Topic: 2. Trauma

A 60-year-old female undergoes open reduction and internal fixation of a 2-part surgical neck humerus fracture with a locking plate. Postoperatively, radiographs show that the fracture has collapsed into varus. Which of the following technical errors most likely contributed to this complication?

. Failure to use medial calcar screws
. Placement of the plate too inferiorly
. Over-reduction of the greater tuberosity
. Stripping of the anterior circumflex humeral artery
. Excessive deltoid detachment

Correct Answer & Explanation

. Failure to use medial calcar screws

Explanation

The placement of medial calcar screws provides vital medial column support, which is critical to preventing varus collapse and subsequent screw cut-out in proximal humerus fracture plating.

Question 7314

Topic: 2. Trauma

A 68-year-old female sustains a 4-part proximal humerus fracture. Which of the following radiographic features is the most reliable predictor of humeral head ischemia?

. Greater tuberosity displacement > 1 cm
. Calcar length < 8 mm attached to the articular segment
. Angulation of the articular surface > 45 degrees
. Metaphyseal extension > 2 cm
. An intact medial hinge

Correct Answer & Explanation

. Greater tuberosity displacement > 1 cm

Explanation

Hertel identified that a metaphyseal head extension (calcar length) of less than 8 mm attached to the articular segment and disruption of the medial hinge are the most reliable predictors of humeral head ischemia.

Question 7315

Topic: 2. Trauma

A 60-year-old woman undergoes open reduction and internal fixation with a locking plate for a 3-part proximal humerus fracture. What is the most common complication specifically associated with this fixation method?

. Atrophic nonunion
. Avascular necrosis of the humeral head
. Intra-articular screw penetration (screw cut-out)
. Axillary nerve injury
. Deep surgical site infection

Correct Answer & Explanation

. Atrophic nonunion

Explanation

The most common complication following locked plating of proximal humerus fractures is intra-articular screw penetration. This often occurs due to osteoporotic bone settling and varus collapse, causing the rigid locking screws to cut out through the articular surface.

Question 7316

Topic: 2. Trauma

A 65-year-old man undergoes open reduction and internal fixation with a locking plate for a 3-part proximal humerus fracture. Two months postoperatively, radiographs show varus collapse of the humeral head and intra-articular screw cutout. Which of the following technical errors most likely contributed to this failure?

. Failure to obtain medial calcar cortical support
. Placement of screws into the greater tuberosity
. Use of a deltopectoral approach instead of anterolateral
. Overtightening of the locking screws
. Failure to repair the subscapularis tendon

Correct Answer & Explanation

. Failure to obtain medial calcar cortical support

Explanation

Failure to restore medial cortical support (the medial calcar) in proximal humerus fractures significantly increases the risk of postoperative varus collapse. Medial support can be achieved by anatomic reduction, impaction of the shaft into the head, or using an endosteal fibular strut graft.

Question 7317

Topic: 2. Trauma

A 38-year-old male presents with a persistent, mobile, and painful nonunion of a midshaft transverse humerus fracture 8 months after nonoperative management in a functional brace. He has no neurovascular deficits. What is the gold standard surgical treatment?

. Exchange functional bracing and bone stimulator
. Antegrade intramedullary nailing
. Open reduction and compression plating with autologous bone grafting
. External fixation
. Vascularized free fibula transfer

Correct Answer & Explanation

. Exchange functional bracing and bone stimulator

Explanation

The gold standard for atrophic or symptomatic long-standing humeral shaft nonunions is open reduction, rigid internal fixation with compression plating, and the addition of autologous bone graft (such as from the iliac crest) to provide both mechanical stability and biological stimulus.

Question 7318

Topic: Upper Extremity Trauma

Historically, the anterior humeral circumflex artery was believed to be the primary blood supply to the humeral head. Recent anatomic studies have demonstrated that the primary arterial supply to the proximal humerus actually arises from which of the following vessels?

. Thoracoacromial artery
. Posterior humeral circumflex artery
. Suprascapular artery
. Circumflex scapular artery
. Profunda brachii artery

Correct Answer & Explanation

. Thoracoacromial artery

Explanation

Recent quantitative perfusion studies have overturned historical teaching, proving that the posterior humeral circumflex artery provides the vast majority (up to 64%) of the blood supply to the humeral head.

Question 7319

Topic: 2. Trauma

A 45-year-old man undergoes treatment for a humerus shaft fracture using an antegrade intramedullary nail. Which of the following is the most commonly reported long-term complication unique to this specific surgical approach compared to plating?

. Persistent shoulder pain and impingement
. Increased rate of nonunion
. Iatrogenic radial nerve palsy
. Heterotopic ossification of the elbow
. Coracoid process avulsion

Correct Answer & Explanation

. Persistent shoulder pain and impingement

Explanation

Antegrade intramedullary nailing of the humerus is heavily associated with postoperative shoulder pain and rotator cuff dysfunction, primarily due to violation of the rotator cuff insertion and superior hardware prominence.

Question 7320

Topic: 2. Trauma

A 40-year-old male sustains a midshaft humerus fracture. He is managed nonoperatively in a functional brace. Which of the following radiographic parameters exceeds the acceptable limits for conservative management of a humeral shaft fracture?

. 2 cm of shortening
. 15 degrees of anterior angulation
. 20 degrees of varus angulation
. 35 degrees of varus angulation
. 10 degrees of valgus angulation

Correct Answer & Explanation

. 2 cm of shortening

Explanation

Acceptable alignment criteria for nonoperative management of a humeral shaft fracture include <20 degrees of anterior/posterior bowing, <30 degrees of varus/valgus angulation, and <3 cm of shortening. A 35-degree varus deformity is unacceptable and warrants surgical fixation.

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