Menu

9. Shoulder and Elbow MCQs

Practice Set 61 of 197

This practice set contains high-yield board review questions covering key concepts in 9. Shoulder and Elbow. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 1201

Topic: 9. Shoulder and Elbow
A 37-year-old electrician is diagnosed with a frozen shoulder after sustaining an electrical injury at work 2 weeks ago. Examination reveals that he cannot actively or passively externally rotate or abduct the arm. The glenohumeral joint and scapula move in a 1:1 ratio. Radiographs are shown in Figures 15a and 15b. The best course of action should be
. vigorous physical therapy for passive range of motion.
. manipulation of the shoulder under anesthesia.
. an intra-articular steroid injection.
. an axillary radiograph.
. MRI.

Correct Answer & Explanation

. an axillary radiograph.

Explanation

DISCUSSION: The patientโ€™s history, examination, and radiographs are classic for locked posterior dislocation of the glenohumeral joint. Posterior dislocation of the shoulder remains the most commonly missed dislocation of a major joint. Up to 80% are missed on initial presentation. The primary cause for failure to accurately diagnose this injury is inadequate radiographic evaluation. The typical presentation is a shoulder locked in internal rotation with loss of abduction. An axillary view not only will make the definitive diagnosis but will help assess the size of the articular surface defect and help plan treatment. This view can be done expediently as part of every trauma series. The AP view is suspicious for a posteriorly dislocated humerus with loss of the humeral neck profile, a vacant glenoid sign, and an anterior humeral head compression fracture (reverse Hill-Sachs lesion). REFERENCES: Hawkins RJ, Neer CS II, Pianta RM, Mendoza FX: Locked posterior dislocation of the shoulder. J Bone Joint Surg Am 1987;69:9-18. Norris TR (ed): Orthopaedic Knowledge Update: Shoulder and Elbow. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1997, pp 181-189. Rockwood CA Jr, Thomas SC, Matsen FA III: Subluxations and dislocations about the glenohumeral joint, in Rockwood CA Jr, Green DP, Bucholz RW (eds): Fractures in Adults, ed 3. Philadelphia, PA, JB Lippincott, 1991, vol 1, pp 1058-1065.

Question 1202

Topic: 9. Shoulder and Elbow

A 61-year-old man reports right shoulder pain and loss of external rotation since having a seizure 5 months ago. MRI scans are shown in Figures 82a and 82b. What is the most appropriate treatment? Review Topic

. Closed reduction and application of a shoulder immobilizer
. Open reduction and lesser tuberosity transfer
. Hemiarthroplasty placed in anatomic version
. Hemiarthroplasty placed in anteversion
. Total shoulder arthroplasty

Correct Answer & Explanation

. Closed reduction and application of a shoulder immobilizer

Explanation

The patient has a chronic posterior shoulder dislocation with loss of approximately half of the humeral head. Hemiarthroplasty or osteochondral allograft to fill the defect would be required. Given the time since injury, the remaining native head and articular surface may have lost structural integrity, making hemiarthroplasty the preferred choice. The implant should be placed close to the patient's natural version, which normally is in the range of 20 to 30 degrees of retroversion. Excessive anteversion is not recommended to avoid repeat posterior dislocation. Closed reduction is highly unlikely to achieve a reduction and may cause displacement of an unrecognized humeral surgical neck fracture. Open reduction and lesser tuberosity transfer is best suited for smaller head defects and a less chronic dislocation. Glenoid integrity is not affected, thus a glenoid implant is unnecessary.

Question 1203

Topic: Elbow & Forearm

A 35-year-old male presents with recurrent clicking and apprehension when pushing up from a chair 6 months after an elbow dislocation. Which ligament is primarily deficient, and what is the typical path of subluxation?

. Anterior bundle of the medial collateral ligament; radius translates anteriorly
. Lateral ulnar collateral ligament; radius and ulna subluxate posterolaterally away from the humerus
. Radial collateral ligament; ulna subluxates posteromedially
. Annular ligament; radius translates inferiorly
. Lateral ulnar collateral ligament; ulna hinges on the intact MCL

Correct Answer & Explanation

. Anterior bundle of the medial collateral ligament; radius translates anteriorly

Explanation

Posterolateral rotatory instability (PLRI) is caused by a deficiency of the lateral ulnar collateral ligament (LUCL). During provocative maneuvers (like pushing off a chair), the radius and ulna supinate and subluxate posterolaterally away from the humerus as a single unit.

Question 1204

Topic: Elbow & Forearm

During surgical reconstruction of a 'terrible triad' injury of the elbow, what is the standard recommended sequence of repair to progressively restore stability?

. Radial head, coronoid, lateral collateral ligament (LCL)
. Coronoid, radial head, lateral collateral ligament (LCL)
. LCL, radial head, coronoid
. Coronoid, LCL, radial head
. Radial head, LCL, coronoid

Correct Answer & Explanation

. Radial head, coronoid, lateral collateral ligament (LCL)

Explanation

The standard sequence for terrible triad repair is deep to superficial, anterior to posterior. The coronoid is addressed first (via suture lasso, screw, or plate), followed by radial head fixation or arthroplasty, and finally LCL repair to the lateral epicondyle.

Question 1205

Topic: 9. Shoulder and Elbow

What is the primary biomechanical advantage of a reverse total shoulder arthroplasty (RTSA) in the setting of rotator cuff tear arthropathy?

. It lateralizes the center of rotation, increasing deltoid efficiency
. It medializes and distalizes the center of rotation, increasing the deltoid moment arm
. It relies on the intact subscapularis to act as a fulcrum
. It restores the anatomic center of rotation to optimize the remaining rotator cuff
. It shifts the center of rotation superiorly to tension the remaining cuff

Correct Answer & Explanation

. It lateralizes the center of rotation, increasing deltoid efficiency

Explanation

According to Grammont's principles, a reverse shoulder arthroplasty medializes and distalizes the center of rotation of the glenohumeral joint. This increases the moment arm of the deltoid, recruits more deltoid muscle fibers, and increases resting tension, allowing the deltoid to effectively elevate the arm in the absence of a functional rotator cuff.

Question 1206

Topic: Elbow & Forearm
A 42-year-old female sustains an elbow injury. Radiographs reveal a type IV Bryan and Morrey capitellum fracture. What is the defining characteristic of this fracture pattern?
. Complete articular shear fracture of the capitellum with little or no extension into the trochlea
. A thin shell of articular cartilage separated from the capitellum
. Comminuted fracture of the capitellum
. Coronal shear fracture involving the capitellum and extending medially to involve the majority of the trochlea
. Fracture of the capitellum extending into the lateral epicondyle

Correct Answer & Explanation

. Coronal shear fracture involving the capitellum and extending medially to involve the majority of the trochlea

Explanation

In the Bryan and Morrey classification of capitellar fractures: Type I (Hahn-Steinthal) is a large osseous segment. Type II (Kocher-Lorenz) is an articular cartilage shell. Type III is comminuted. Type IV (McKee modification) is a coronal shear fracture that involves both the capitellum and a significant portion of the trochlea.

Question 1207

Topic: Elbow & Forearm

A 9-year-old boy presents with a cubitus varus deformity 3 years after a supracondylar humerus fracture. He is asymptomatic, but if left uncorrected, what is the most significant potential late functional complication of this deformity?

. Median nerve palsy
. Tardy ulnar nerve palsy
. Posterolateral rotatory instability (PLRI)
. Valgus extension overload
. Ulnar collateral ligament attenuation

Correct Answer & Explanation

. Median nerve palsy

Explanation

While initially a cosmetic issue, the mechanical axis deviation in cubitus varus causes the triceps to pull in a medially displaced vector. Over years, this repetitive eccentric loading stretches the lateral ulnar collateral ligament (LUCL) complex, eventually predisposing the patient to tardy posterolateral rotatory instability (PLRI) and ulnar neuropathy. Tardy ulnar nerve palsy is classically associated with cubitus valgus.

Question 1208

Topic: Elbow & Forearm

A 38-year-old bodybuilder undergoes distal biceps tendon repair using a single anterior incision technique. Postoperatively, he exhibits weakness in extending the wrist and fingers, though wrist drop is incomplete. The affected nerve most likely runs between which two muscle bellies near the level of the radial neck?

. Brachialis and Brachioradialis
. Supinator and Extensor Carpi Radialis Brevis
. Superficial and deep heads of the Supinator
. Flexor Carpi Ulnaris and Flexor Digitorum Profundus
. Pronator Teres and Flexor Carpi Radialis

Correct Answer & Explanation

. Brachialis and Brachioradialis

Explanation

The posterior interosseous nerve (PIN) is at risk during a single-incision distal biceps repair, particularly with aggressive lateral retraction. The PIN enters the arcade of Frohse and travels through the supinator muscle, specifically between its superficial and deep heads.

Question 1209

Topic: 9. Shoulder and Elbow

A 72-year-old female undergoes a reverse total shoulder arthroplasty (rTSA) for severe rotator cuff tear arthropathy. Which of the following best describes the fundamental biomechanical alteration achieved by the rTSA implant design compared to native anatomy?

. Lateralizes and superiorizes the center of rotation
. Medializes and distalizes the center of rotation
. Lateralizes and distalizes the center of rotation
. Medializes and superiorizes the center of rotation
. Maintains the native center of rotation but increases the articular constraint

Correct Answer & Explanation

. Lateralizes and superiorizes the center of rotation

Explanation

The reverse total shoulder arthroplasty (rTSA) inherently medializes and distalizes the center of rotation of the glenohumeral joint. Medialization increases the number of deltoid fibers recruited for elevation, while distalization tensions the deltoid, increasing its moment arm. This allows the deltoid to effectively compensate for the deficient rotator cuff.

Question 1210

Topic: Elbow & Forearm

A 34-year-old male falls on an outstretched arm and sustains an elbow injury. Examination reveals varus posteromedial rotatory instability (VPMRI). Which of the following injury patterns is most classically associated with this specific physical examination finding?

. Radial head fracture with medial ulnar collateral ligament tear
. Coronoid tip fracture with anterior capsule avulsion
. Anteromedial facet coronoid fracture with lateral collateral ligament tear
. Olecranon fracture with distal biceps rupture
. Capitellum fracture with lateral ulnar collateral ligament tear

Correct Answer & Explanation

. Radial head fracture with medial ulnar collateral ligament tear

Explanation

Varus posteromedial rotatory instability (VPMRI) is caused by an axial load combined with a varus force. It classically presents with a fracture of the anteromedial facet of the coronoid and an associated avulsion or tear of the lateral collateral ligament (LCL) complex. This contrasts with posterolateral rotatory instability (PLRI) which involves radial head/coronoid tip fractures (terrible triad).

Question 1211

Topic: Elbow & Forearm

A 14-year-old elite gymnast presents with lateral elbow pain and catching. Radiographs reveal a radiolucent lesion in the capitellum. The pathogenesis of this condition is most directly related to which of the following?

. Traction apophysitis of the lateral epicondyle
. Repetitive valgus overload causing tensile failure of the lateral collateral ligament
. Repetitive compressive/shear forces acting on the precarious end-arterial blood supply of the capitellum
. A primary inflammatory arthropathy affecting the radiocapitellar joint
. Anomalous insertion of the extensor carpi radialis brevis

Correct Answer & Explanation

. Repetitive compressive/shear forces acting on the precarious end-arterial blood supply of the capitellum

Explanation

Osteochondritis dissecans (OCD) of the capitellum is predominantly seen in adolescent throwing athletes and gymnasts. It is caused by repetitive valgus compression and shear forces at the radiocapitellar joint. The capitellum is particularly vulnerable due to its tenuous, end-arterial blood supply.

Question 1212

Topic: Shoulder Pathology

A 28-year-old patient presents with symptomatic scapular winging following a posterior triangle lymph node biopsy. On examination, the scapula rests in a translated lateral and downwardly rotated position. The winging is accentuated when the patient abducts the arm against resistance. Which nerve is most likely injured?

. Long thoracic nerve
. Spinal accessory nerve
. Dorsal scapular nerve
. Suprascapular nerve
. Axillary nerve

Correct Answer & Explanation

. Spinal accessory nerve

Explanation

Spinal accessory nerve (CN XI) injury leads to trapezius palsy, causing 'lateral winging' (scapula is displaced laterally and downwardly rotated). This is often an iatrogenic complication of posterior cervical triangle biopsy. Lateral winging is accentuated by resisted shoulder abduction. In contrast, long thoracic nerve injury (serratus anterior palsy) causes 'medial winging' which is worsened by forward elevation/wall push-ups.

Question 1213

Topic: Elbow & Forearm

A 45-year-old male sustains a terrible triad injury of the elbow following a fall. Intraoperatively, the surgeon decides on a single lateral approach. What is the recommended sequence of anatomical repair to systematically restore elbow stability?

. Lateral ulnar collateral ligament, coronoid process, radial head
. Coronoid process, radial head, lateral ulnar collateral ligament
. Radial head, coronoid process, lateral ulnar collateral ligament
. Coronoid process, lateral ulnar collateral ligament, radial head
. Radial head, lateral ulnar collateral ligament, coronoid process

Correct Answer & Explanation

. Coronoid process, radial head, lateral ulnar collateral ligament

Explanation

Standard management of terrible triad injuries proceeds from deep to superficial. The coronoid (and anterior capsule) is repaired first, followed by the radial head (repair or arthroplasty), and finally the lateral ulnar collateral ligament.

Question 1214

Topic: Shoulder Arthroplasty & Arthritis

A 72-year-old female undergoes a reverse total shoulder arthroplasty for cuff tear arthropathy. How does the biomechanical design of the prosthesis primarily improve active elevation?

. It lateralizes and superiorizes the center of rotation to tension the remaining rotator cuff.
. It medializes and inferiorizes the center of rotation to increase the deltoid moment arm.
. It increases deltoid wrapping without altering the anatomical center of rotation.
. It decreases the deltoid moment arm to prevent secondary acromial stress fractures.
. It restores the normal anatomic center of rotation but limits external rotation.

Correct Answer & Explanation

. It medializes and inferiorizes the center of rotation to increase the deltoid moment arm.

Explanation

A reverse total shoulder arthroplasty shifts the center of rotation medially and inferiorly. This change recruits more deltoid muscle fibers and significantly increases its moment arm, compensating for the absent rotator cuff.

Question 1215

Topic: 9. Shoulder and Elbow

A 30-year-old male sustains an Essex-Lopresti injury. During surgery, the highly comminuted radial head is excised and not replaced. What is the most likely biomechanical complication of this omission?

. Varus elbow instability and capitellar wear
. Proximal migration of the radius and ulnocarpal impaction
. Distal radioulnar joint ankylosis
. Ulnar nerve traction neuritis
. Posterolateral rotatory instability of the elbow

Correct Answer & Explanation

. Proximal migration of the radius and ulnocarpal impaction

Explanation

An Essex-Lopresti injury involves a longitudinal radioulnar dissociation with interosseous membrane disruption. Excision of the radial head removes the primary proximal stabilizer, leading to severe proximal radial migration and ulnocarpal impaction syndrome.

Question 1216

Topic: 9. Shoulder and Elbow

During an arthroscopic anterior Bankart repair on a right shoulder, the surgeon places a suture anchor at the 5:30 position on the glenoid rim. Which major anatomical structure is primarily tensioned by shifting the labrum superiorly at this position?

. Coracohumeral ligament
. Superior glenohumeral ligament
. Middle glenohumeral ligament
. Anterior band of the inferior glenohumeral ligament
. Posterior band of the inferior glenohumeral ligament

Correct Answer & Explanation

. Anterior band of the inferior glenohumeral ligament

Explanation

The anterior band of the inferior glenohumeral ligament (IGHL) typically attaches to the glenoid at the 5 to 6 o'clock position (in a right shoulder). Tensioning this structure is critical to restoring anterior stability.

Question 1217

Topic: Elbow & Forearm

A 45-year-old male undergoes a single-incision anterior repair of a distal biceps tendon rupture. Postoperatively, he is unable to actively extend his fingers or thumb, but wrist extension is partially preserved with a radial deviation bias. Which nerve was injured during the approach?

. Lateral antebrachial cutaneous nerve
. Posterior interosseous nerve
. Superficial radial nerve
. Median nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Posterior interosseous nerve

Explanation

The posterior interosseous nerve (PIN) is at risk during single-incision anterior distal biceps repairs, especially with vigorous radial retraction. PIN injury causes finger/thumb extension loss, but radial wrist extension remains via the ECRL (innervated by the radial nerve proper).

Question 1218

Topic: Shoulder Arthroplasty & Arthritis

In reverse total shoulder arthroplasty (RTSA), inferior tilt and inferior overhang of the glenosphere are primarily designed to prevent which of the following complications?

. Scapular notching
. Glenoid aseptic loosening
. Acromial stress fracture
. Anterior dislocation
. Greater tuberosity resorption

Correct Answer & Explanation

. Scapular notching

Explanation

Scapular notching is a common complication of RTSA caused by mechanical impingement of the humeral component against the scapular neck. Inferior tilt and overhang of the glenosphere laterally clear the implant from the bone, significantly reducing this risk.

Question 1219

Topic: 9. Shoulder and Elbow

A 25-year-old male presents with a locked posterior shoulder dislocation. Which of the following mechanisms of injury is most classically associated with a traumatic posterior dislocation?

. Forced abduction and external rotation
. Direct blow to the anterior acromion
. Fall onto an outstretched arm that is adducted, flexed, and internally rotated
. Repetitive microtrauma during the late cocking phase of throwing
. Traction injury to the superior labrum

Correct Answer & Explanation

. Fall onto an outstretched arm that is adducted, flexed, and internally rotated

Explanation

Traumatic posterior shoulder dislocations classically occur from axial loading on an adducted, flexed, and internally rotated arm. Seizures and electrocution are other common causes due to powerful internal rotator muscle contraction.

Question 1220

Topic: Elbow & Forearm

A 40-year-old female presents with posterolateral rotatory instability (PLRI) of the elbow. During the lateral pivot-shift test of the elbow, at what degree of flexion does maximal subluxation of the radial head typically occur?

. 0 to 10 degrees
. 40 to 50 degrees
. 70 to 80 degrees
. 90 to 100 degrees
. 110 to 120 degrees

Correct Answer & Explanation

. 40 to 50 degrees

Explanation

In PLRI, the lateral ulnar collateral ligament (LUCL) is deficient. During the pivot-shift test, the radial head maximally subluxates posteriorly at approximately 40 to 50 degrees of flexion before reducing as flexion increases.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page