Upper Extremity Orthopedic MCQs: ABOS Trauma Review

Question 1

You are interested in learning a new technique for minimally invasive total knee arthroplasty. The Keyhole Genuflex system seems appealing to you because the instrumentation comes with wireless controls. Which of the following represents an acceptable arrangement?

Explanation

Both the AAOS and AdvaMed, the medical device manufacturer's trade organization, have written guidelines that address potential conflicts of interest regarding interactions between physicians and manufacturer's representatives when it comes to patients' best interest. The AAOS feels that the orthopaedic profession exists for the primary purpose of caring for the patient and that the physician-patient relationship is the central focus of all ethical concerns. When an orthopaedic surgeon receives anything of significant value from industry, a potential conflict of interest exists. The AAOS believes that it is acceptable for industry to provide financial and other support to orthopaedic surgeons if such support has significant educational value and has the purpose of improving patient care. All dealings between orthopaedic surgeons and industry should benefit the patient and be able to withstand public scrutiny. A gift of any kind from industry should in no way influence the orthopaedic surgeon in determining the most appropriate treatment for his or her patient. Orthopaedic surgeons should not accept gifts or other financial support with conditions attached. Subsidies by industry to underwrite the costs of educational events where CME credits are provided can contribute to the improvement of patient care and are acceptable. A corporate subsidy received by the conference's sponsor is acceptable; however, direct industry reimbursement for an orthopaedic surgeon to attend a CME educational event is not appropriate. Special circumstances may arise in which orthopaedic surgeons may be required to learn new surgical techniques demonstrated by an expert or to review new implants or other devices on-site. In these circumstances, reimbursement for expenses may be appropriate. AAOS Standard of Professionalism -Orthopaedist -Industry Conflict of Interest (Adopted 4/18/07), Mandatory Standard numbers 6, 9, 12-15. http://www3.aaos.org/member/profcomp/SOPConflictsIndustry.pdf The Orthopaedic Surgeon's Relationship with Industry, in Guide to the Ethical Practice of Orthopaedic Surgery, ed 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2007. http://www.aaos.org/about/papers/ethics/1204eth.asp

Question 2

A 65-year-old female sustains a 4-part proximal humerus fracture. According to Hertel's criteria, which of the following radiographic findings is the most reliable predictor of humeral head ischemia?

Explanation

Hertel's criteria identify calcar length < 8 mm, disrupted medial hinge > 2 mm, and a basicervical fracture pattern as the strongest predictors of humeral head ischemia. Preserved medial soft tissue attachments are critical for perfusion.

Question 3

A 42-year-old male sustains a terrible triad injury of the elbow. Which of the following represents the most widely accepted surgical sequence for restoring stability?

Explanation

The standard sequence for a terrible triad injury is coronoid fixation, followed by radial head repair or replacement, and finally lateral collateral ligament (LCL) repair. This inside-out approach restores the anterior buttress before reconstructing the lateral column.

Question 4

In evaluating a 65-year-old female with a 4-part proximal humerus fracture, which of the following radiographic findings is the strongest predictor of humeral head ischemia?

Explanation

According to Hertel's criteria, a metaphyseal head extension (calcar length) of < 8 mm, disrupted medial hinge, and an anatomic neck fracture pattern are the most reliable predictors of ischemia. Of these, a short calcar segment is highly indicative of vascular compromise to the articular fragment.

Question 5

Which of the following parameters represents a generally accepted indication for operative fixation of a significantly displaced scapular body or neck fracture?

Explanation

Indications for operative intervention in scapula fractures include a glenopolar angle < 22 degrees, medial/lateral translation > 25 mm, and angulation > 45 degrees. A severely decreased glenopolar angle alters the mechanics of the rotator cuff and warrants fixation.

Question 6

Which of the following is the strongest independent predictor of nonunion when treating a midshaft clavicle fracture nonoperatively?

Explanation

Complete displacement with no cortical apposition is the most significant risk factor for nonunion in midshaft clavicle fractures. Other associated risk factors include advancing age, smoking, and severe initial shortening.

Question 7

When surgically managing a 'Terrible Triad' injury of the elbow, what is the recommended standard sequence of repair to restore stability?

Explanation

The standard algorithm for a Terrible Triad injury works deep to superficial and inside out: fix the coronoid first, then fix or replace the radial head, and finally repair the lateral ulnar collateral ligament (LUCL). The medial collateral ligament is only repaired if the elbow remains unstable after these steps.

Question 8

In an independent 75-year-old female with a highly comminuted, intra-articular distal humerus fracture, what is the primary advantage of total elbow arthroplasty (TEA) compared to open reduction internal fixation (ORIF)?

Explanation

In elderly patients with severe comminution or osteopenia, TEA allows for immediate mobilization and yields more predictable early functional outcomes compared to ORIF. However, TEA imposes a lifelong 5-pound lifting restriction and carries a higher long-term complication rate.

Question 9

A coronal shear fracture of the distal humerus involving the capitellum and the majority of the trochlea is classified as which of the following?

Explanation

In the Bryan and Morrey classification of capitellum fractures, a Type IV (added by McKee) represents a coronal shear fracture that extends medially to include the capitellum and the majority of the trochlea. This pattern often requires an expansile surgical approach for adequate fixation.

Question 10

Which nerve injury is most commonly associated with a Bado Type I (anterior) Monteggia fracture-dislocation?

Explanation

The posterior interosseous nerve (PIN) is the most commonly injured nerve in Bado Type I (anterior) and Type III (lateral) Monteggia fractures. The injury is typically a neuropraxia that resolves spontaneously with conservative management.

Question 11

A 35-year-old man sustains an acute Essex-Lopresti injury with a highly comminuted, unsalvageable radial head. What is the most appropriate definitive management?

Explanation

An Essex-Lopresti injury involves a radial head fracture, interosseous membrane tear, and DRUJ disruption. Radial head excision alone leads to proximal radial migration; therefore, a rigid metallic radial head arthroplasty and DRUJ stabilization are required to prevent longitudinal radioulnar dissociation.

Question 12

Following anatomic rigid internal fixation of the radius in a Galeazzi fracture, the distal radioulnar joint (DRUJ) remains irreducible. Which structure is most likely interposing and blocking reduction?

Explanation

In Galeazzi fracture-dislocations, an irreducible DRUJ is typically caused by interposition of the extensor carpi ulnaris (ECU) tendon. Less commonly, the median or ulnar nerve can become entrapped.

Question 13

In the natural history of Scapholunate Advanced Collapse (SLAC), Stage III arthritic changes classically involve which of the following articulations?

Explanation

SLAC progresses in predictable stages: Stage I involves the radial styloid, Stage II encompasses the entire radioscaphoid joint, and Stage III progresses to the capitolunate joint. The radiolunate joint is characteristically spared due to the concentric shape of the lunate fossa.

Question 14

A 45-year-old male sustains a terrible triad injury to the elbow. During surgical reconstruction, what is the most appropriate sequence of repair to restore elbow stability?

Explanation

The standard sequence for terrible triad reconstruction is 'inside-out': coronoid fixation, radial head fixation or replacement, followed by LCL repair. The MCL is typically only repaired if the elbow remains grossly unstable after the primary three structures are addressed.

Question 15

According to the Hertel criteria, which of the following radiographic findings is the most reliable predictor of humeral head ischemia following a proximal humerus fracture?

Explanation

Hertel criteria predicting humeral head ischemia include a short metaphyseal head extension (calcar length < 8 mm), disruption of the medial periosteal hinge, and an anatomical neck fracture. The combination of these factors significantly increases the risk of avascular necrosis.

Question 16

A 24-year-old male presents with a proximal pole scaphoid fracture. You elect to proceed with percutaneous screw fixation. Which surgical approach and screw trajectory offer the best mechanical advantage and easiest access for a proximal pole fracture?

Explanation

Proximal pole scaphoid fractures are best approached dorsally to allow a proximal-to-distal screw trajectory. This approach minimizes damage to the precarious blood supply entering distally and allows central placement of the screw in the small proximal fragment.

Question 17

A 30-year-old cyclist sustains a midshaft clavicle fracture. Which of the following is considered an absolute indication for open reduction and internal fixation?

Explanation

Absolute indications for operative fixation of clavicle fractures include open fractures, neurovascular compromise, and threatened skin breakdown. Displacement, shortening, and comminution are considered strong relative indications.

Question 18

A 40-year-old female sustains a coronal shear fracture of the distal humerus extending into the trochlea (Dubberley Type 2B). What surgical approach is most appropriate for direct visualization and anterior-to-posterior fixation?

Explanation

Coronal shear fractures involving the capitellum and extending into the trochlea are best managed via an extended lateral approach, often elevating the common extensor origin. This provides excellent visualization of the anterior articular surface for anterior-to-posterior screw fixation.

Question 19

In evaluating a patient with recurrent anterior shoulder instability, what degree of critical glenoid bone loss is generally considered the threshold to proceed with a Latarjet procedure rather than an arthroscopic Bankart repair?

Explanation

Critical glenoid bone loss is typically defined as 20-25% of the inferior glenoid width. Defects of this size or greater significantly increase the failure rate of isolated soft tissue (Bankart) stabilization, necessitating a bony augmentation procedure like the Latarjet.

Question 20

According to Mayfield's stages of perilunate instability, what is the defining pathoanatomy of the final stage (Stage IV)?

Explanation

Mayfield Stage IV represents a complete lunate dislocation, where the dorsal radiocarpal ligaments fail, and the lunate is extruded volarly into the carpal tunnel. Stage I is scapholunate failure, Stage II is capitate dislocation, and Stage III is lunotriquetral failure.

Question 21

A 28-year-old male sustains a Galeazzi fracture. Following open reduction and internal fixation of the radial shaft, the distal radioulnar joint (DRUJ) remains grossly unstable in all forearm positions. What is the most appropriate first step in management?

Explanation

In a Galeazzi fracture, the most common cause of persistent DRUJ instability after fixation of the radius is non-anatomic reduction (shortening or malrotation) of the radial shaft. The surgeon must first re-evaluate and perfectly correct the radius fixation before addressing the TFCC directly or pinning the joint.

Question 22

A 45-year-old man falls on an outstretched hand, sustaining a 'terrible triad' injury of the elbow. To optimally restore elbow kinematics and stability, which of the following represents the most widely accepted surgical sequence?

Explanation

The standard inside-out surgical sequence for a terrible triad injury is fixation of the coronoid first, followed by the radial head, and finally the LCL complex. This systematically builds stability from the deep anterior structures to the lateral stabilizers.

Question 23

A 35-year-old sustains a comminuted radial head fracture, a torn interosseous membrane, and distal radioulnar joint (DRUJ) instability. If the surgeon erroneously performs a radial head excision without arthroplasty, what is the most likely long-term complication?

Explanation

This patient has an Essex-Lopresti injury. Excision of the radial head without replacement in the setting of a disrupted interosseous membrane leads to uninhibited proximal migration of the radius, causing severe ulnocarpal impaction and wrist pain.

Question 24

During open reduction and internal fixation of a 3-part proximal humerus fracture with a locked plate, the surgeon places inferomedial calcar screws. What is the primary biomechanical purpose of these specific screws?

Explanation

Inferomedial calcar screws provide critical structural support to the inferomedial humeral head, acting as a buttress. This significantly reduces the risk of postoperative varus collapse, particularly when the medial hinge is comminuted.

Question 25

Understanding the vascular anatomy of the scaphoid is essential for managing acute fractures and nonunions. Which of the following best describes the primary arterial supply to the scaphoid?

Explanation

The scaphoid receives 70-80% of its blood supply from the dorsal carpal branch of the radial artery, which enters at the distal pole and flows in a retrograde fashion to the proximal pole. This retrograde flow is why proximal pole fractures are at high risk for avascular necrosis.

Question 26

A 55-year-old woman presents with sudden inability to actively flex the interphalangeal joint of her thumb. She underwent volar locked plating for a distal radius fracture 6 months ago. What is the most likely anatomical etiology of this complication?

Explanation

Placement of a volar plate distal to the watershed line of the distal radius can cause mechanical attrition and subsequent rupture of the flexor pollicis longus (FPL) tendon. The watershed line marks the safe distal limit for hardware placement.

Question 27

A 40-year-old man presents with a locked posterior shoulder dislocation after a seizure. CT imaging reveals an anteromedial humeral head defect (reverse Hill-Sachs lesion) involving 35% of the articular surface. What is the most appropriate surgical management?

Explanation

For reverse Hill-Sachs lesions involving 20-40% of the articular surface, a modified McLaughlin procedure (transfer of the lesser tuberosity with the attached subscapularis tendon into the defect) provides excellent stability. Defects >40-50% generally require arthroplasty.

Question 28

During an anatomic reconstruction of the coracoclavicular (CC) ligaments for a chronic Type V acromioclavicular dislocation, accurate footprint placement is crucial. Which of the following describes the normal anatomic orientation of the CC ligaments on the clavicle?

Explanation

The conoid ligament inserts posteromedially on the conoid tubercle (roughly 4.5 cm from the distal clavicle). The trapezoid ligament inserts anterolaterally (roughly 3.0 cm from the distal clavicle).

Question 29

A 55-year-old presents with a Bado Type II Monteggia fracture (posterior apex ulnar fracture with posterior radial head dislocation). What associated injury is most frequently seen with this specific fracture pattern in adults?

Explanation

Bado Type II (posterior Monteggia) lesions are the most common Monteggia variant in adults. They are highly associated with concomitant radial head or neck fractures, which can complicate the management of radiocapitellar stability.

Question 30

According to Mayfield's stages of perilunate instability, what structural failure characterizes the transition from a Stage III (perilunate dislocation) to a Stage IV (lunate dislocation)?

Explanation

In Mayfield Stage IV, the dorsal radiocarpal ligament fails. The lunate then rotates volarly into the carpal tunnel, hinging on the intact short volar radiolunate ligament, resulting in a classic lunate dislocation.

Question 31

Hertel's radiographic criteria are utilized to predict ischemia of the humeral head following a proximal humerus fracture. Which combination of findings carries the highest positive predictive value for avascular necrosis?

Explanation

Hertel identified that the combination of an anatomic neck fracture, a short calcar segment attached to the articular fragment (<8 mm), and a disrupted medial hinge (>2 mm displacement) carries a 97% positive predictive value for humeral head ischemia.

Question 32

A 45-year-old female sustains a fall on an outstretched hand resulting in an elbow dislocation, a comminuted radial head fracture, and a Type II coronoid fracture. During surgical management of this 'terrible triad' injury, what is the most widely accepted sequence of repair?

Explanation

The standard surgical algorithm for terrible triad injuries proceeds from deep to superficial. This involves coronoid fixation or anterior capsular repair, followed by radial head repair or replacement, and finally LCL complex repair.

Question 33

A 25-year-old male presents with a 2-mm displaced fracture of the scaphoid waist following a fall. Surgical fixation is planned. Which of the following is the primary advantage of a volar percutaneous or mini-open approach over a dorsal approach for this specific fracture?

Explanation

The primary blood supply to the scaphoid enters dorsally at the wrist and supplies the proximal pole in a retrograde fashion. A volar approach is preferred for waist fractures to avoid disrupting this critical dorsal vascularity.

Question 34

A 60-year-old female requires open reduction and internal fixation for a Type IV coronal shear fracture of the capitellum that extends into the trochlea (Dubberley Type 3B). Extensive posterior dissection is performed. What is the most significant risk associated with this surgical approach?

Explanation

Extensive posterior dissection and stripping of the lateral column to address coronal shear fractures disrupt the tenuous intraosseous blood supply, significantly increasing the risk of avascular necrosis of the capitellum.

Question 35

A 30-year-old male cyclist presents with a midshaft clavicle fracture. Which of the following is considered an absolute indication for operative fixation?

Explanation

Absolute indications for ORIF of a clavicle fracture include open fractures, vascular compromise, and progressive neurologic deficits. Displacement, shortening, and skin tenting are generally considered relative indications.

Question 36

A 50-year-old male presents with chronic wrist pain and a history of remote trauma. Radiographs reveal advanced arthritis of the radioscaphoid and capitolunate joints, with sparing of the radiolunate joint. This radiographic pattern is highly characteristic of which stage of Scapholunate Advanced Collapse (SLAC)?

Explanation

SLAC Stage III is characterized by arthritic changes in the radioscaphoid and capitolunate joints. The radiolunate joint is typically spared due to the concentric, purely spherical articulation that does not develop abnormal shear forces.

Question 37

A 65-year-old female sustains a 4-part proximal humerus fracture. According to Hertel's criteria, which of the following radiographic findings is the most reliable predictor of ischemia to the humeral head?

Explanation

Hertel identified that a calcar length (metaphyseal extension) of less than 8 mm and disruption of the medial periosteal hinge are the strongest predictors of humeral head ischemia and subsequent avascular necrosis.

Question 38

A 35-year-old male undergoes ORIF of the radius for a distal-third radial shaft fracture with associated distal radioulnar joint (DRUJ) instability (Galeazzi fracture). Intraoperatively, after anatomic radius fixation, the DRUJ remains grossly irreducible in all forearm positions. What is the most appropriate next step?

Explanation

If the DRUJ remains irreducible after anatomic restoration of the radius in a Galeazzi fracture, open exploration is required. The most common cause is soft tissue interposition, typically the extensor carpi ulnaris (ECU) tendon.

Question 39

A 40-year-old male sustains a severe Essex-Lopresti injury. If the comminuted radial head is primarily excised without replacement, what is the most likely long-term biomechanical complication?

Explanation

An Essex-Lopresti injury involves a radial head fracture, tear of the interosseous membrane, and DRUJ disruption. Excision of the radial head without replacement removes the proximal longitudinal stabilizer, leading to proximal radial migration and ulnocarpal impingement.

Question 40

An 18-year-old male is brought to the emergency department after a motor vehicle collision complaining of chest pain, dysphagia, and shortness of breath. Examination reveals a posterior sternoclavicular joint dislocation. What is the most appropriate management strategy?

Explanation

Posterior sternoclavicular dislocations can compress mediastinal structures, risking life-threatening vascular or tracheal injuries. Reduction must be performed in the OR under general anesthesia with a cardiothoracic surgeon on standby.

Question 41

A pediatric patient sustains a Bado Type I Monteggia fracture (anterior dislocation of the radial head with anterior bowing/fracture of the ulna). Following ulnar reduction and plating, the radial head remains persistently dislocated anteriorly. What is the most common cause of this failure of reduction?

Explanation

The most common reason for failure of the radial head to reduce in a Monteggia fracture is incomplete restoration of ulnar length or failure to recreate the anatomic posterior bow of the proximal ulna.

Question 42

A 55-year-old female undergoes volar locked plating for a distal radius fracture. Six weeks postoperatively, she suddenly loses the ability to actively extend her thumb interphalangeal joint. What is the most likely iatrogenic cause of this complication?

Explanation

Rupture of the extensor pollicis longus (EPL) tendon following volar plating of the distal radius is most frequently caused by prominent screws penetrating the dorsal cortex into the third extensor compartment.

Question 43

A 30-year-old male presents with a Hahn-Steinthal (Type I) capitellum fracture, characterized by a large osseous fragment involving the subchondral bone. Which surgical approach provides the most direct and appropriate exposure for internal fixation?

Explanation

The Kocher approach, utilizing the internervous plane between the anconeus (radial nerve) and the extensor carpi ulnaris (posterior interosseous nerve), provides excellent direct access to the capitellum and lateral column.

Question 44

A 25-year-old male undergoes tension band wiring for a simple transverse olecranon fracture. Which of the following is the most frequently reported complication associated with this specific fixation technique?

Explanation

Symptomatic hardware is the most common complication of tension band wiring for olecranon fractures, occurring in up to 40-80% of cases and frequently necessitating a second surgery for hardware removal.

Question 45

A 32-year-old male falls on an extended, ulnarly deviated wrist. Radiographs demonstrate a 'spilled teacup' sign on the lateral view and overlapping carpal arcs on the PA view. According to Mayfield's stages of perilunate instability, which structure is the first to fail in this cascade?

Explanation

Mayfield's cascade of perilunate instability occurs in four stages, beginning radially and progressing ulnarly. The scapholunate ligament is the first structure to fail (Stage I).

Question 46

A 45-year-old male presents with a highly comminuted, isolated fracture of the scapular body following a high-energy fall. The glenoid and scapular neck are intact. What is the most appropriate primary treatment?

Explanation

The vast majority of extra-articular scapular body fractures heal well with non-operative management (sling and early ROM) because they are highly vascularized and splinted by the surrounding robust musculature.

Question 47

A 50-year-old female requires dual plating for a severely comminuted intra-articular distal humerus fracture (AO/OTA 13C3). Based on current orthopedic consensus, what is the recommended management of the ulnar nerve during this procedure?

Explanation

Current evidence suggests that routine anterior transposition of the ulnar nerve is unnecessary and may increase the risk of neuritis. In situ decompression is preferred, with transposition reserved for cases where the nerve subluxates or rubs against implants.

Question 48

A 22-year-old male presents with recurrent anterior shoulder dislocations. A 3D CT scan reveals 10% anterior glenoid bone loss and a large, engaging Hill-Sachs lesion that is classified as 'off-track'. Which of the following procedures effectively converts this lesion to an 'on-track' lesion without requiring bony augmentation of the glenoid?

Explanation

An off-track Hill-Sachs lesion will engage the anterior glenoid rim, causing failure of isolated Bankart repair. Arthroscopic Remplissage (tenodesis of the infraspinatus into the defect) fills the defect, effectively converting it to an on-track lesion.

Question 49

A 30-year-old male weightlifter feels a sudden 'pop' and tearing sensation in his chest while performing a heavy bench press. Examination reveals loss of the anterior axillary fold contour and weakness in shoulder internal rotation. Where is the most common anatomic location for this specific rupture?

Explanation

Pectoralis major ruptures almost exclusively occur in young, active males engaged in weightlifting. The most common site of injury is an avulsion of the tendon directly from its insertion on the lateral lip of the bicipital groove of the humerus.

Question 50

A 28-year-old male sustains a severe crush injury to the forearm and develops acute compartment syndrome. Emergent volar and dorsal fasciotomies are performed. To adequately decompress the 'mobile wad of Henry', the fascia over which of the following muscle groups must be released?

Explanation

The mobile wad of Henry is a distinct compartment in the forearm that comprises three muscles: the brachioradialis, the ECRL, and the ECRB. It must be specifically released during dorsal forearm fasciotomy.

Question 51

A 22-year-old male presents with severe chest pain and shortness of breath after a rugby tackle. Radiographs and a CT scan reveal a posterior sternoclavicular joint dislocation. What is the most appropriate next step in management?

Explanation

Posterior SC dislocations can compress critical mediastinal structures. Closed reduction should be attempted in the operating room with cardiothoracic surgery backup due to the significant risk of catastrophic vascular injury.

Question 52

A 65-year-old female undergoes volar locking plate fixation for a distal radius fracture. Six months later, she is unable to actively flex the interphalangeal joint of her thumb. Which of the following technical errors most likely led to this complication?

Explanation

Flexor pollicis longus (FPL) rupture is a known complication of volar plating. It is most commonly caused by placing the plate at or distal to the watershed line, causing frictional wear on the tendon.

Question 53

A 24-year-old male presents 3 weeks after a fall onto an outstretched hand. MRI confirms a non-displaced proximal pole scaphoid fracture. What is the blood supply to the proximal pole of the scaphoid and the optimal management?

Explanation

The proximal pole relies on a retrograde blood supply from the dorsal carpal branch of the radial artery, making it prone to avascular necrosis. Due to high nonunion rates and prolonged healing times, screw fixation is generally recommended over casting for proximal pole fractures.

Question 54

A 35-year-old male sustains a closed transverse fracture of the middle third of the humeral shaft. On examination, he has a weak wrist drop but normal triceps extension. He is treated with a functional brace. At 12 weeks, there is no clinical or EMG evidence of radial nerve recovery. What is the next best step?

Explanation

Radial nerve palsy associated with a closed humeral shaft fracture is initially observed. However, if there is no clinical or EMG evidence of recovery by 3 to 4 months, surgical exploration of the nerve is indicated.

Question 55

A 28-year-old male sustains a distal third radial shaft fracture with associated distal radioulnar joint (DRUJ) dislocation. After rigid plate fixation of the radius, the DRUJ remains irreducible. Which of the following structures is most commonly blocking reduction?

Explanation

In a Galeazzi fracture-dislocation, if the DRUJ is irreducible following anatomic fixation of the radius, soft tissue interposition should be suspected. The extensor carpi ulnaris (ECU) tendon is the most common structure blocking reduction.

Question 56

Which of the following radiographic findings in an acute midshaft clavicle fracture is the strongest independent predictor of nonunion with nonoperative management?

Explanation

Lack of cortical contact (complete displacement) is the strongest independent risk factor for nonunion in midshaft clavicle fractures. While shortening > 2cm is also a factor, complete displacement has been shown to be more predictive.

Question 57

A 45-year-old male sustains a severe closed scapula fracture following a high-speed motorcycle accident. Which of the following radiographic parameters is considered an absolute indication for open reduction and internal fixation?

Explanation

An intra-articular glenoid step-off of greater than 4-5 mm is an absolute indication for surgical fixation of a scapula fracture to prevent post-traumatic arthritis. A glenopolar angle < 22 degrees is considered a relative indication.

Question 58

A 78-year-old female with severe rheumatoid arthritis presents with a highly comminuted, intra-articular distal humerus fracture. What is the primary advantage of total elbow arthroplasty (TEA) compared to open reduction and internal fixation (ORIF) in this patient?

Explanation

In elderly patients with severe osteopenia and comminuted distal humerus fractures, TEA offers a more predictable restoration of functional range of motion and allows early mobilization. However, TEA patients require lifelong lifting restrictions.

Question 59

A 33-year-old female sustains a highly comminuted radial head fracture. During examination, she complains of severe wrist pain, and radiographs show proximal migration of the radius. Which of the following treatments is absolutely contraindicated?

Explanation

This patient has an Essex-Lopresti lesion, consisting of a radial head fracture, interosseous membrane tear, and DRUJ disruption. Radial head excision alone is contraindicated as it leads to unchecked proximal migration of the radius and severe ulnocarpal impaction.

Question 60

A 26-year-old construction worker falls off a ladder and sustains a wrist injury. Radiographs reveal a perilunate dislocation. According to Mayfield's stages of perilunate instability, which ligament is injured first?

Explanation

According to Mayfield's stages of progressive perilunate instability, the injury begins radially and progresses ulnarly. Stage I involves disruption of the scapholunate ligament.

Question 61

Following surgical repair of a terrible triad elbow injury (radial head replacement, coronoid fixation, and LCL repair), a patient is noted to have a persistent block to forearm pronation. Which of the following is the most likely cause?

Explanation

An oversized (overstuffed) radial head prosthesis after a terrible triad injury causes excessive radiocapitellar pressure. This leads to a mechanical block in forearm rotation, most commonly pronation, as well as limited flexion.

Question 62

A 7-year-old boy sustains a Bado Type I Monteggia fracture-dislocation. Closed reduction of the ulna is achieved, but the radial head remains anteriorly dislocated. What is the most appropriate next step?

Explanation

In pediatric Monteggia fractures, the radial head dislocation is almost always secondary to the ulnar deformity. If the radial head remains dislocated, it usually means ulnar length or bow is not adequately restored, so improving the ulnar reduction is the critical next step.

Question 63

A 42-year-old male undergoes tension band wiring for a transverse olecranon fracture. Postoperatively, he is unable to flex the interphalangeal joint of the thumb and the distal interphalangeal joint of the index finger. What structure was likely injured?

Explanation

The anterior interosseous nerve (AIN) can be injured by overly long Kirschner wires penetrating the anterior cortex of the ulna during tension band wiring. AIN palsy presents with weakness of the FPL and FDP to the index finger.

Question 64

A 38-year-old female sustains a fracture of the capitellum that extends medially to include the lateral aspect of the trochlea, with a separate posterior comminuted fragment. According to the Dubberley classification, what type of fracture is this?

Explanation

The Dubberley classification distinguishes capitellar fractures based on trochlear extension. Type 3 involves both the capitellum and the trochlea. The "B" modifier indicates posterior condylar comminution.

Question 65

A 35-year-old male sustains a closed scapula fracture following a motorcycle accident. Which of the following radiographic parameters is considered a strong indication for operative fixation of the scapular neck?

Explanation

A glenopolar angle of less than 22 degrees is a widely accepted indication for operative intervention in scapula neck fractures. Other indications include >20mm of medialization or >40 degrees of angulation.

Question 66

A 28-year-old female presents with an elbow injury. Radiographs and CT reveal a coronal shear fracture of the capitellum that extends medially to include the lateral trochlear ridge. According to the modified Bryan-Morrey classification, what type of fracture is this?

Explanation

A Bryan-Morrey Type IV fracture, as described by McKee, involves a coronal shear fracture of the capitellum extending to include the lateral trochlear ridge. This fragment creates significant articular instability and typically requires operative fixation.

Question 67

A 22-year-old male sustains a proximal pole scaphoid fracture. The high rate of avascular necrosis associated with this specific injury pattern is primarily due to the retrograde blood supply entering the scaphoid via which of the following vessels?

Explanation

The scaphoid receives its primary blood supply in a retrograde fashion from the dorsal carpal branch of the radial artery, which enters at the dorsal ridge. Proximal pole fractures disrupt this precarious intraosseous supply, leading to high rates of AVN.

Question 68

Which of the following factors is the most reliable independent predictor of nonunion in conservatively managed, completely displaced midshaft clavicle fractures?

Explanation

Initial fracture shortening greater than 2 cm is one of the strongest independent risk factors for nonunion in nonoperatively managed midshaft clavicle fractures. Lack of cortical apposition (100% displacement) and comminution also significantly increase the nonunion risk.

Question 69

An anteromedial facet fracture of the coronoid process typically results from varus posteromedial rotatory instability (VPMRI) of the elbow. Which ligamentous structure is most commonly ruptured in this specific injury pattern?

Explanation

VPMRI is caused by a varus force on the elbow, leading to rupture of the lateral collateral ligament complex (specifically the LUCL) and a shearing fracture of the anteromedial facet of the coronoid. Treatment requires addressing both the bony and ligamentous instability.

Question 70

A 60-year-old female presents 6 weeks after a nondisplaced distal radius fracture treated in a short arm cast. She complains of a new inability to actively extend her thumb interphalangeal joint. What is the most appropriate definitive management?

Explanation

Delayed EPL rupture after a nondisplaced distal radius fracture occurs due to watershed ischemia and mechanical attrition at the Lister tubercle. Primary repair is typically impossible due to tendon degeneration and retraction, making EIP to EPL transfer the gold standard.

Question 71

A 25-year-old cyclist falls directly onto his shoulder. Examination reveals skin tenting over a prominent distal clavicle. Radiographs show a 150% superior displacement of the clavicle relative to the acromion. What is the most appropriate management according to the Rockwood classification?

Explanation

This is a Rockwood Type V acromioclavicular joint dislocation, characterized by >100% superior displacement of the clavicle and disruption of the deltotrapezial fascia. Operative management with CC ligament reconstruction is indicated due to severe displacement and gross instability.

Question 72

According to the Mayfield classification of progressive perilunate instability, what structural failure marks the final sequence (Stage IV) of the injury cascade?

Explanation

Mayfield Stage IV represents a complete volar lunate dislocation into the carpal tunnel following disruption of the dorsal radiocarpal ligaments. This represents the terminal event of the progressive perilunate destabilization sequence.

Question 73

A 6-year-old boy sustains a fracture of the proximal ulna with an associated anterior dislocation of the radial head. According to the Bado classification, what type of Monteggia lesion is this?

Explanation

A Bado Type I Monteggia fracture is defined by an anterior dislocation of the radial head combined with an anteriorly angulated fracture of the ulnar diaphysis. It is the most common Monteggia lesion encountered in the pediatric population.

Question 74

A 19-year-old male sustains a posterior sternoclavicular joint dislocation during a rugby match. He complains of mild dysphagia but is hemodynamically stable. What is the most critical next step in management?

Explanation

Posterior sternoclavicular dislocations can compress critical mediastinal structures, causing dysphagia, dyspnea, or vascular compromise. A CT scan with contrast is mandatory to assess displacement and identify threatened mediastinal anatomy prior to any reduction attempt.

Question 75

When utilizing an olecranon osteotomy for open reduction and internal fixation of a complex intra-articular distal humerus fracture, which osteotomy configuration is associated with the highest biomechanical stability and lowest risk of articular step-off?

Explanation

An apex-distal chevron osteotomy directed through the non-articular bare area of the sigmoid notch provides excellent exposure, maximizes bony contact, and interlocks securely to prevent articular step-off during closure.

Question 76

A 32-year-old male sustains a Galeazzi fracture-dislocation. Which of the following factors makes the distal radioulnar joint (DRUJ) most likely to require operative stabilization after anatomic rigid fixation of the radius?

Explanation

Galeazzi fractures located within 7.5 cm of the radiocarpal articular surface have a significantly higher rate of DRUJ instability following anatomic radial fixation. These injuries frequently require secondary DRUJ pinning or open TFCC repair.

Question 77

During an anterolateral deltoid-splitting approach for minimally invasive plate osteosynthesis (MIPO) of a proximal humerus fracture, what is the generally accepted safe distance from the lateral tip of the acromion to avoid injury to the axillary nerve?

Explanation

The axillary nerve courses circumferentially from posterior to anterior approximately 5 to 7 cm distal to the lateral edge of the acromion. Extending the deltoid split beyond 5 cm places the nerve at significant risk of iatrogenic transection.

Question 78

A 45-year-old male falls from a ladder and presents with a comminuted radial head fracture, severe wrist pain, and positive ulnar variance on radiographs. To prevent progressive longitudinal radioulnar dissociation, which operative step is strictly contraindicated?

Explanation

This patient has an Essex-Lopresti injury (radial head fracture, interosseous membrane disruption, DRUJ disruption). Excision of the radial head without replacement is strictly contraindicated, as it removes the proximal strut and leads to devastating proximal radial migration.

Question 79

In the typical progression of Scapholunate Advanced Collapse (SLAC) wrist, which carpal articulation is characteristically spared from degenerative joint disease?

Explanation

In SLAC wrist, the radiolunate joint is characteristically spared from osteoarthritis because the lunate fossa is concentric and the lunate cartilage is maintained despite the bone extending into a DISI deformity. The radioscaphoid joint is the first to degenerate.

Question 80

A 50-year-old male sustains a proximal-third humeral shaft fracture. The proximal fragment is abducted and externally rotated, while the distal fragment is displaced proximally and medially. Which muscle is primarily responsible for the medial displacement of the distal fragment?

Explanation

In a humeral shaft fracture located between the insertions of the rotator cuff and the pectoralis major, the proximal fragment is abducted/externally rotated by the cuff. The distal fragment is pulled medially and proximally by the pectoralis major, latissimus dorsi, and teres major.

Question 81

A 45-year-old female treated non-operatively for a minimally displaced distal radius fracture presents 6 weeks later with a sudden inability to actively extend her thumb interphalangeal joint. What is the most likely pathophysiologic mechanism for this complication?

Explanation

Extensor pollicis longus (EPL) tendon rupture is a known complication of nondisplaced or minimally displaced distal radius fractures. It typically occurs due to attritional wear over the intact but roughened bony anatomy at Lister's tubercle, combined with local ischemia in the third dorsal compartment.

Question 82

Which of the following accurately describes the primary blood supply to the scaphoid, predisposing proximal pole fractures to a high rate of nonunion?

Explanation

The primary blood supply to the scaphoid is retrograde, provided by the dorsal carpal branch of the radial artery which enters at the dorsal ridge near the distal pole. This retrograde flow makes proximal pole fractures highly susceptible to avascular necrosis and subsequent nonunion.

Question 83

A 25-year-old male sustains a midshaft clavicle fracture. Which of the following combinations of radiographic findings most significantly increases his risk of nonunion if treated non-operatively?

Explanation

Risk factors for nonunion in midshaft clavicle fractures include completely displaced fractures (>100% translation), significant shortening (>2 cm), and severe comminution. Operative fixation in patients with these specific characteristics significantly decreases nonunion rates compared to conservative management.

Question 84

A 22-year-old rugby player presents with recurrent anterior shoulder instability. A 3D CT scan reveals a 30% anteroinferior glenoid bone defect. Which of the following is the most appropriate surgical management?

Explanation

Critical glenoid bone loss (>20-25%) in the setting of recurrent anterior shoulder instability is an absolute indication for a bony augmentation procedure, such as the Latarjet. Soft tissue stabilization (Bankart repair) alone in this setting has an unacceptably high failure and recurrence rate.

Question 85

A 40-year-old female falls on an outstretched hand and sustains a coronal shear fracture of the distal humerus that involves the capitellum and extends medially to include the majority of the trochlea. According to the Bryan and Morrey classification with McKee's modification, what type of fracture is this?

Explanation

The McKee modification added the Type IV fracture to the Bryan and Morrey classification. A Type IV lesion represents a coronal shear fracture that involves the capitellum and extends medially to include the majority of the trochlea, often necessitating separate medial and lateral internal fixation.

Question 86

A 45-year-old male is involved in a high-speed motor vehicle collision and sustains a scapular body fracture. Which of the following radiographic parameters is considered an absolute indication for open reduction and internal fixation?

Explanation

Operative indications for scapula fractures include intra-articular glenoid displacement > 4 mm, a glenopolar angle < 22 degrees, or medialization > 20 mm. A glenopolar angle of 35 degrees is within normal limits.

Question 87

An 82-year-old woman with severe rheumatoid arthritis and advanced osteoporosis sustains a highly comminuted, intra-articular distal humerus fracture (AO/OTA 13-C3). What is the most appropriate definitive management to maximize functional recovery and minimize reoperation?

Explanation

Total elbow arthroplasty (TEA) is the preferred treatment for highly comminuted, intra-articular distal humerus fractures in elderly patients with poor bone quality or pre-existing inflammatory arthritis. TEA allows for immediate range of motion and has lower reoperation rates compared to ORIF in this demographic.

Question 88

A 30-year-old male sustains a Galeazzi fracture-dislocation. After rigid anatomic plate fixation of the radial shaft, the distal radioulnar joint (DRUJ) remains grossly unstable in supination. What is the most appropriate next step in management?

Explanation

If the DRUJ remains unstable after anatomic fixation of the radius in a Galeazzi fracture, especially in supination, it indicates a significant block to reduction or severe soft tissue disruption. Open reduction of the DRUJ with TFCC repair and/or temporary radioulnar pinning is required to restore stability.

Question 89

A 28-year-old male presents with a swollen, painful wrist after falling from a ladder. Radiographs demonstrate a volar perilunate dislocation. He complains of severe numbness and tingling in his thumb, index, and middle fingers. Which anatomic mechanism is most directly responsible for these neurologic symptoms?

Explanation

Perilunate and lunate dislocations frequently cause acute carpal tunnel syndrome because the lunate rotates and displaces volarly directly into the carpal tunnel. This causes acute mechanical compression of the median nerve, necessitating urgent reduction.

Question 90

In the context of elbow trauma, the anteromedial facet of the coronoid is critical for resisting varus posteromedial rotatory instability. Which ligamentous structure attaches directly to the sublime tubercle on the anteromedial facet?

Explanation

The anterior bundle of the medial ulnar collateral ligament (MUCL) inserts onto the sublime tubercle, which is located on the anteromedial facet of the coronoid process. Fractures involving this facet compromise the MUCL insertion, leading to varus posteromedial rotatory instability of the elbow.

100 High-Yield Orthopedic MCQs: Shoulder & Elbow | Mock Exam 251

Upper Extremity Orthopedic MCQs (Set 6): Shoulder, Elbow & Wrist Trauma | ABOS Review

Key Takeaway

Upper Extremity Orthopedic MCQs (Set 6): Shoulder, Elbow & Wrist Trauma | ABOS Review

Chapter Index