ABOS Part I & AAOS OITE Orthopaedic Surgery Review: Clinical Cases & Exam Questions | Part 22139

ABOS Part I Review modules offer advanced orthopedic multiple-choice questions mirroring the ABOS Part I and AAOS OITE examinations. Content is derived from high-yield clinical teaching cases, covering essential topics like shoulder dislocations, fracture fixation principles, and orthopedic screw biomechanics to ensure comprehensive exam preparation.

ABOS Part I & AAOS OITE Orthopaedic Surgery Exam Review

Question 1

A 24-year-old male presents to the emergency department after a football injury, complaining of severe right shoulder pain. His arm is held in slight abduction and external rotation. On inspection, the anterior aspect of his shoulder appears prominent, and there is a palpable void beneath the acromion. Which of the following physical exam findings is MOST concerning for an associated neurovascular injury in this patient?

Explanation

Correct Answer: D

An absent radial pulse is a critical finding indicating potential compromise of the brachial artery, which is a surgical emergency. While axillary nerve injury (loss of sensation over the lateral deltoid, weakness in abduction) is the most common nerve injury with anterior shoulder dislocations, it is rarely an acute limb-threatening condition unless it's a traction injury without spontaneous recovery. Weakness in wrist extension would suggest radial nerve involvement, which is less common. Ecchymosis is a common finding but not acutely life- or limb-threatening.

Question 2

A 35-year-old patient presents with a history of recurrent anterior shoulder dislocations. During your examination, you perform the Apprehension Test. Which of the following describes a positive test?

Explanation

Correct Answer: A

The Apprehension Test is performed by abducting the shoulder to 90 degrees and slowly externally rotating the arm. A positive test is indicated by the patient's feeling of impending dislocation (apprehension) or significant pain, often due to stretching of the anterior capsule. Options B and C describe findings related to rotator cuff or glenohumeral arthritis. Option D describes the Sulcus Sign, indicative of inferior or multidirectional instability. Option E describes a clunk, which could be related to labral pathology but is not the apprehension test.

Question 3

A 50-year-old patient presents with acute shoulder pain after a seizure. On examination, the arm is held in internal rotation, and the anterior shoulder appears flattened. External rotation is severely restricted. Which radiographic finding on an AP shoulder view is pathognomonic for a posterior shoulder dislocation?

Explanation

Correct Answer: C

The Trough line sign (or reverse Hill-Sachs lesion) is an impaction fracture on the anterior-medial aspect of the humeral head, often seen with posterior dislocations. The other options are incorrect: Hill-Sachs and Bankart lesions are typically associated with anterior dislocations. HAGL lesions are avulsions of the glenohumeral ligaments, often associated with anterior dislocations. Os acromiale is an anatomical variant.

Question 4

During the examination of a patient with suspected shoulder dislocation, you note a sulcus sign. What does this finding MOST commonly indicate?

Explanation

Correct Answer: C

The Sulcus Sign is elicited by applying inferior traction to the arm, causing a dimple or sulcus to appear below the acromion. It is indicative of inferior capsular laxity and is a hallmark of inferior or multidirectional glenohumeral instability. While multidirectional instability often includes an inferior component, the most direct interpretation of a sulcus sign is inferior instability.

Question 5

A 68-year-old woman falls directly onto her shoulder. She presents with severe pain and an inability to move her arm. On exam, the shoulder appears abducted, and a prominent hard mass is palpable inferior to the glenoid, consistent with a Luxatio Erecta. Which neurovascular structure is at highest risk of injury in this type of dislocation?

Explanation

Correct Answer: C

Luxatio Erecta (inferior dislocation) involves extreme abduction, forcing the humeral head inferiorly. The head can impinge upon or stretch the neurovascular bundle in the axilla. The axillary artery is at significant risk due to its proximity and the severe displacement. While the axillary nerve and brachial plexus are also at risk, arterial compromise (axillary artery) is a more acute and limb-threatening complication associated with the extreme force and direction of displacement in luxatio erecta, often leading to intimal tears or thrombosis.

Question 6

Following reduction of an anterior shoulder dislocation, a patient complains of persistent weakness in active shoulder abduction. Sensation over the lateral aspect of the deltoid is intact. Which of the following is the MOST likely cause of this isolated weakness?

Explanation

Correct Answer: B

If sensation over the lateral deltoid (axillary nerve sensory distribution) is intact, persistent isolated weakness in shoulder abduction, especially in an older patient or high-energy trauma, should raise suspicion for an associated rotator cuff tear (supraspinatus or deltoid dysfunction). Axillary nerve neuropraxia would typically present with sensory deficits in addition to motor weakness. Musculocutaneous nerve injury affects biceps and coracobrachialis, and lateral forearm sensation. Long thoracic nerve injury causes scapular winging. Brachial plexus avulsion would present with more widespread neurological deficits.

Question 7

A 22-year-old male presents with his first-time anterior shoulder dislocation. During the initial assessment, which of the following is a critical component of the examination PRIOR to any reduction attempts?

Explanation

Correct Answer: C

A thorough neurovascular examination of the affected extremity, including palpation of pulses and assessment of sensation and motor function, is paramount before any reduction attempts. This establishes a baseline and helps identify any pre-existing or acute neurovascular compromise that could be exacerbated by or misattributed to the reduction maneuver. Analgesia is important but secondary to neurovascular assessment. Contralateral shoulder ROM is not critical pre-reduction. Ice is for comfort. Family history is irrelevant in acute management.

Question 8

You are examining a patient with a suspected posterior shoulder dislocation. Which maneuver is most likely to confirm your suspicion on physical exam?

Explanation

Correct Answer: C

Posterior dislocations classically present with the arm held in internal rotation and adduction, with a significant block to external rotation. The anterior shoulder may appear flattened, and the coracoid process prominent. Apprehension with abduction and external rotation is characteristic of anterior instability. Limited internal rotation with intact external rotation is incorrect. Increased superior translation with anterior force is not directly indicative of posterior dislocation. A palpable defect below the coracoid is more suggestive of anterior dislocation.

Question 9

Which finding on a post-reduction physical exam of an anterior shoulder dislocation indicates successful reduction and suggests stability?

Explanation

Correct Answer: B

Successful reduction is indicated by the restoration of normal shoulder contour (loss of the anterior prominence of the humeral head), relief of severe pain, and the ability to achieve full or near-full passive range of motion without a 'block.' Persistent apprehension or instability signs (like a sulcus sign or continued apprehension with external rotation) suggest potential underlying pathology or incomplete reduction. Crepitus might indicate cartilage damage, and inability to actively abduct could suggest a rotator cuff tear or nerve injury, not necessarily unsuccessful reduction.

Question 10

A 70-year-old male sustains an anterior shoulder dislocation. After reduction, plain radiographs show a concomitant fracture. Which fracture is MOST commonly associated with anterior shoulder dislocation in this age group?

Explanation

Correct Answer: B

While Hill-Sachs and Bankart lesions are very common with anterior dislocations, in older patients, a greater tuberosity fracture is particularly common (up to 30% in some series) due to the weaker bone and the forces involved in the injury. The rotator cuff avulses a piece of the tuberosity during the dislocation. Surgical neck fracture is also possible but less frequent than greater tuberosity in direct association with dislocation. Clavicle fractures are less directly associated with glenohumeral dislocation mechanism.

Question 11

A resident is reviewing the basic anatomy of an orthopedic screw. Referring to the provided image, which labeled component is primarily responsible for providing a smooth, unthreaded link between the screw head and the threaded portion?

Explanation

Correct Answer: B

The case explicitly states, 'The shank provides a smooth link between the head and thread.' The image clearly labels the shank as the unthreaded portion immediately distal to the head. The head (A) provides a connection for a screwdriver and prevents sinking. The thread (C) engages with the bone. Pitch (D) is the distance between adjacent threads. Flutes (E) provide a route for bone debris removal.

Question 12

A 68-year-old female with osteoporotic bone requires internal fixation for a distal femur fracture. To maximize the pull-out strength of the screws in this challenging bone quality, which of the following biomechanical principles should the surgeon prioritize?

Explanation

Correct Answer: C

The case states that pull-out strength can be increased by 'increasing thread density' or by having a 'finer' pitch, which allows more turns of the spiral thread to engage in a given depth of cortex, creating greater resistance to pull-out. Options A and B would decrease the contact surface area or thread depth, thereby reducing pull-out strength. Option D directly contradicts the principle of increasing engaged threads. Option E (larger pilot hole) is a surgeon factor that reduces pull-out strength.

Question 13

During a complex ankle fracture fixation, a junior resident inadvertently makes a pilot hole slightly larger than recommended for the chosen screw. This technical error is most likely to result in which of the following?

Explanation

Correct Answer: C

The case explicitly lists 'making too large a pilot hole' as a surgeon factor that can reduce screw pull-out strength. A larger pilot hole reduces the contact area between the screw threads and the bone, diminishing the frictional and mechanical interlock necessary for strong fixation. Options A, B, D, and E are incorrect as a larger pilot hole would generally weaken the fixation, not strengthen it or improve insertion characteristics in a beneficial way.

Question 14

A surgeon is selecting a screw for metaphyseal fixation in a comminuted proximal humerus fracture, where bone quality may be compromised. To optimize the screw's resistance to axial dislodgement, which characteristic related to the screw's thread design would be most beneficial?

Explanation

Correct Answer: C

The case states, 'The 'finer' the pitch, the more turns of the spiral thread engage in a given depth of cortex, creating greater resistance to pull-out.' A finer pitch means more threads per unit length, increasing the contact surface area with the bone. A larger lead (A) or coarser pitch (B) would mean fewer threads engaged. A shallower thread depth (D) or smaller outer diameter (E) would reduce the contact surface area, thereby decreasing pull-out strength.

Question 15

In a scenario where a surgeon aims to maximize the pull-out strength of a non-locking screw in cortical bone, which combination of screw diameter characteristics would be most advantageous?

Explanation

Correct Answer: C

The case indicates that pull-out strength can be increased by 'increasing the contact surface area between screw threads and bone, either by increasing the outer diameter, decreasing the core diameter.' This combination (increased outer diameter and decreased core diameter) results in a greater thread depth, maximizing the volume of bone engaged by the screw threads and thus increasing the resistance to pull-out. Options A, B, and D would either reduce the thread depth or the overall screw-bone contact. Option E describes a smooth pin, not a screw.

Question 16

A 55-year-old male sustains a periprosthetic femur fracture around a total hip arthroplasty stem. The surgeon opts for plate and screw fixation. The use of locking screws in this context primarily enhances stability by:

Explanation

Correct Answer: B

The case states, 'The use of a locking screw can also create a monobloc effect for greater stability.' Locking screws thread into the plate, creating a fixed-angle construct that acts as a single unit (monobloc) with the bone, providing enhanced stability, especially in osteoporotic bone or comminuted fractures. They do not primarily rely on screw-plate friction (A) or provide dynamic compression (C) in the same way non-locking screws do. They increase, rather than reduce, the stiffness of the construct (D). Flutes, not locking screws, facilitate bone debris removal (E).

Question 17

During a revision surgery for a failed ankle fusion, a surgeon attempts to re-insert a screw into a previously drilled hole. After initial resistance, the screw feels loose and does not achieve adequate purchase. This situation is most likely due to:

Explanation

Correct Answer: C

The case identifies 'repeated withdrawal and reintroduction of a screw causing damage to the negative threads in the bone tissue' as a surgeon factor that can reduce screw pull-out strength. When a screw is removed and reinserted, the bone threads (negative threads) can be stripped or damaged, leading to poor purchase and reduced pull-out strength upon reinsertion. Insufficient pilot hole depth (A) would typically lead to difficulty inserting the screw initially, not looseness after reinsertion. Over-tightening (B) could strip the threads on the first attempt, but the scenario describes re-insertion. An excessively fine pitch (D) would increase pull-out strength, not decrease it. The type of screw (E) is not the primary cause of this specific failure mode.

Question 18

A biomechanical engineer is testing various orthopedic screw designs. The primary parameter being measured when assessing a screw's "pull-out strength" is the:

Explanation

Correct Answer: C

The case clearly defines pull-out strength: 'A screw's pull-out strength refers to the axial force required to remove a screw from bone.' Options A, B, D, and E describe other mechanical properties of screws (torsional strength, bending strength, fatigue strength, compressive strength) but not specifically pull-out strength, which is a measure of resistance to axial extraction.

Question 19

A 72-year-old patient with severe osteoporosis undergoes open reduction and internal fixation of a proximal tibia fracture. The surgeon is particularly concerned about screw pull-out. Which of the following intraoperative strategies would provide the greatest cumulative benefit in maximizing screw pull-out strength in this patient?

Explanation

Correct Answer: B

This option combines multiple strategies mentioned in the case to maximize pull-out strength. The case states that pull-out strength can be increased by 'increasing the number of threads engaged in the bone cortex' and by using a 'finer' pitch. An undersized pilot hole (the opposite of 'too large a pilot hole' which reduces strength) would maximize thread purchase. Option A describes characteristics that would decrease pull-out strength (larger core, coarser pitch). Option C suggests avoiding locking screws, which the case states 'create a monobloc effect for greater stability,' and micro-motion is generally undesirable for fixation. Option D (repeated insertion/removal) is explicitly listed as a factor that reduces pull-out strength. Option E (smaller outer diameter, larger lead) would reduce thread engagement and pull-out strength.

Question 20

Referring to the provided image, the component labeled 'Depth' is crucial for a screw's pull-out strength. According to the case, how does the 'Depth' of a screw thread primarily contribute to its resistance against axial removal from bone?

Explanation

Correct Answer: B

The case states, 'the depth determines the amount of contact with bone for resistance to pull-out.' A greater thread depth allows for more bone engagement and thus a larger contact surface area, which directly increases pull-out strength. Option A describes the lead. Option C describes the function of flutes. Option D describes the pitch. Option E describes the shank.

Question 21

A 45-year-old male sustains a comminuted mid-shaft femoral fracture (OTA/AO 32-C3) in a high-energy trauma. He is hemodynamically stable. Which of the following is the most appropriate initial surgical approach concerning reaming?

Explanation

Correct Answer: C

For a hemodynamically stable patient with a comminuted mid-shaft femoral fracture, immediate reamed intramedullary nailing is generally the preferred approach. Reaming clears the medullary canal, allowing for a larger diameter nail, which provides greater bending and torsional stiffness, leading to superior biomechanical stability and higher rates of union. While unreamed nailing might be considered in polytrauma patients who are unstable or have significant pulmonary compromise to reduce the risk of fat embolism, a stable patient benefits from reamed nailing. Staged procedures are often reserved for patients who are initially unstable. External fixation is typically a temporizing measure. Percutaneous plating is not the standard of care for a comminuted mid-shaft femoral fracture due to inferior load-sharing capabilities compared to IM nailing.

Question 22

Regarding the entry point for an antegrade femoral intramedullary nail, which statement is most accurate to prevent iatrogenic injury?

Explanation

Correct Answer: A

While both piriformis fossa and trochanteric entry points are utilized, the piriformis fossa entry point, when properly executed, is considered to minimize the risk of avascular necrosis of the femoral head by avoiding excessive penetration into the vascular watershed area of the superior retinacular vessels. However, it can be technically challenging and increase the risk of gluteal muscle damage. A trochanteric tip entry point may risk damage to the gluteus medius and piriformis tendons and can lead to lateral hip pain. A medial-based trochanteric entry point is more likely to cause iatrogenic fracture of the greater trochanter or varus malalignment due to impingement. The size of the nail is determined by the medullary canal, not the entry point directly. Hip pain is often multifactorial but can be higher with more lateral entry points.

Question 23

What is the primary biomechanical advantage of reamed compared to unreamed intramedullary nailing for diaphyseal fractures?

Explanation

Correct Answer: B

The primary biomechanical advantage of reamed intramedullary nailing is the ability to use a larger diameter nail. This significantly increases the nail's moment of inertia, which dramatically improves its bending and torsional stiffness. This enhanced stability is crucial for fracture healing, especially in comminuted or unstable fractures. While reaming does increase intramedullary pressure and transiently disrupts the endosteal blood supply, the long-term benefit of superior stability often outweighs these initial concerns. Reduced thermal necrosis is incorrect, as reaming generates heat. Faster insertion time is not a primary biomechanical advantage, and reaming typically increases insertion time. Preservation of endosteal vascularity is generally better with unreamed nailing.

Question 24

When performing antegrade humeral intramedullary nailing, which specific nerve is most at risk during the proximal locking screw placement?

Explanation

Correct Answer: A

During proximal locking screw placement for an antegrade humeral intramedullary nail, the axillary nerve is most vulnerable. It courses around the surgical neck of the humerus, deep to the deltoid, and is susceptible to injury, particularly with excessively long screws or imprecise drilling techniques in the superolateral aspect of the proximal humerus. The radial nerve is at risk more distally, especially with distal locking or in the spiral groove. The ulnar, musculocutaneous, and median nerves are typically not at high risk with proximal humeral locking screws.

Question 25

A 30-year-old male sustains an open Gustilo-Anderson Type IIIA tibia fracture. After debridement and irrigation, the most appropriate definitive fixation method is:

Explanation

Correct Answer: D

For open Gustilo-Anderson Type IIIA tibia fractures, immediate unreamed intramedullary nailing, after thorough debridement and irrigation, is generally considered the preferred definitive fixation method. Unreamed nailing reduces the theoretical risk of disseminating contaminants into the medullary canal compared to reamed nailing, while still providing stable fixation and promoting early weight-bearing. Reamed nailing in an open fracture setting carries a higher theoretical risk of infection. External fixation is often a temporizing measure for more severe open fractures (e.g., Type IIIB/C) or when soft tissue coverage is an immediate concern, but definitive IM nailing is superior for union rates and function. Plate fixation has higher infection rates in open tibia fractures. Casting is insufficient for an open, unstable tibia fracture.

Question 26

Which of the following conditions is considered a relative contraindication to reamed intramedullary nailing?

Explanation

Correct Answer: D

Severe pulmonary compromise, such as Acute Respiratory Distress Syndrome (ARDS), is a relative contraindication to reamed intramedullary nailing. Reaming can lead to increased intramedullary pressure, release of fat emboli, and inflammatory mediators into the systemic circulation, which can exacerbate existing pulmonary issues. In such cases, unreamed nailing or external fixation might be preferred. Age and obesity are not contraindications per se, though they can pose technical challenges. Active systemic infection is generally a contraindication to any implant surgery. Polytrauma with an ISS < 16 is typically not a contraindication, and IM nailing is often beneficial in these patients.

Question 27

What is the primary role of static locking in intramedullary nailing?

Explanation

Correct Answer: B

Static locking, achieved by placing locking screws both proximally and distally, is primarily used to prevent shortening and rotational instability of the fracture. This is particularly important in unstable or comminuted fractures where axial loading might otherwise lead to collapse. While some controlled micromotion is desirable for callus formation, static locking aims to control excessive motion. Dynamization (removing one set of locking screws) is done to achieve compression, which is the opposite of the initial goal of static locking. Static locking does not inherently reduce implant fatigue failure more than dynamic locking, as fatigue is often due to micromotion. Bending stiffness is generally high with IM nails, and static locking maintains length and rotation, not primarily enhancing bending stiffness over dynamic locking.

Question 28

A patient with a comminuted subtrochanteric femur fracture (AO/OTA 32-C1) is treated with a long cephalomedullary nail. Which reduction maneuver is often necessary to achieve adequate alignment before nail insertion?

Explanation

Correct Answer: D

Subtrochanteric fractures are notoriously difficult to reduce due to the strong deforming forces of the hip musculature (iliopsoas, gluteus medius/minimus, adductors). A femoral distractor or manual traction is often necessary to overcome the powerful adductor spasm and length discrepancy, allowing for proper reduction. Once length is restored, other maneuvers may be needed for rotational and angular control. Knee flexion is more relevant for distal femur fractures (gastrocsoleus pull). External rotation is often the deformity, so internal rotation may be needed. Direct manipulation with a Schanz pin can aid, but overcoming severe shortening/displacement usually requires traction first. Axial compression before achieving length and alignment is counterproductive.

Question 29

What is the most common iatrogenic complication associated with a piriformis fossa entry point for femoral intramedullary nailing?

Explanation

Correct Answer: A

The most common iatrogenic complication associated with a piriformis fossa entry point is postoperative hip pain, often attributed to gluteal tendon irritation or heterotopic ossification (HO) in the gluteal region. While avascular necrosis of the femoral head is a theoretical concern with excessive penetration or damage to the retinacular vessels, it is less common than hip pain/HO. Greater trochanteric fracture is more associated with a lateral entry point. Damage to the superior gluteal neurovascular bundle is possible but less frequent than HO. Varus malunion is more related to an excessively medial entry point or improper reduction, rather than the piriformis fossa specifically.

Question 30

A patient undergoes IM nailing for a femoral shaft fracture. Postoperatively, they develop chest pain, dyspnea, and petechial rash. Which complication is most likely?

Explanation

Correct Answer: C

The classic triad of symptoms – respiratory distress, neurological dysfunction, and a petechial rash – following long bone fracture fixation (especially IM nailing) is highly indicative of Fat Embolism Syndrome (FES). The pathophysiology involves the release of marrow fat into the circulation, leading to mechanical obstruction and inflammatory response in the lungs and other organs. While pulmonary embolism is a possibility after any surgery, the presence of the petechial rash makes FES the more likely diagnosis. Pneumonia and AMI would present differently, and ARDS is a potential severe manifestation of FES but FES is the primary diagnosis here.

Question 31

A 19-year-old college football player sustains a first-time anterior shoulder dislocation during a game. It is successfully reduced in the emergency department. Which of the following factors is the single greatest predictor of recurrent glenohumeral instability in this patient?

Explanation

Age at the time of the first dislocation is the most significant risk factor for recurrent instability. Patients under the age of 20 have recurrence rates approaching 90% with conservative management.

Question 32

A 55-year-old female presents to the clinic two weeks after successfully undergoing closed reduction of an anterior shoulder dislocation. She complains of persistent pain and is unable to actively abduct her arm past 45 degrees. Passive range of motion is full. What is the most likely underlying diagnosis?

Explanation

In patients over the age of 40, anterior shoulder dislocations have a high association with acute rotator cuff tears. Persistent weakness and pain after reduction, with preserved passive motion, should immediately prompt evaluation for a torn rotator cuff.

Question 33

A 24-year-old male presents with recurrent anterior shoulder instability. Diagnostic arthroscopy reveals the anterior-inferior labrum is avulsed from the glenoid margin, but the scapular periosteum remains intact, allowing the labrum to roll medially and inferiorly down the glenoid neck. Which of the following describes this lesion?

Explanation

An Anterior Labroligamentous Periosteal Sleeve Avulsion (ALPSA) lesion is characterized by an intact anterior periosteum that displaces the avulsed labrum medially. Unlike a classic Bankart lesion, the periosteal sleeve is not completely disrupted.

Question 34

A 32-year-old male with a history of multiple anterior shoulder dislocations presents for surgical evaluation. A 3D CT scan of the shoulder reveals 28% anterior glenoid bone loss. Which of the following is the most appropriate definitive surgical intervention?

Explanation

For anterior glenoid bone loss exceeding 20-25%, isolated soft tissue repairs have unacceptably high failure rates. The Latarjet procedure (coracoid transfer) is the gold standard to restore anterior stability through the "triple effect" of bone augmentation and sling effect of the conjoint tendon.

Question 35

During a Latarjet procedure, the coracoid process is osteotomized and transferred to the anterior glenoid. Which two nerves are at the highest risk of iatrogenic injury during the coracoid mobilization and subsequent screw fixation?

Explanation

The musculocutaneous nerve enters the conjoint tendon distally and is at risk during retraction. The axillary nerve courses inferiorly along the joint capsule and is at risk during inferior glenoid preparation and screw placement.

Question 36

A 45-year-old male presents with severe shoulder pain following a generalized tonic-clonic seizure. On examination, his arm is locked in internal rotation. Radiographs demonstrate a locked posterior shoulder dislocation with a 35% anteromedial humeral head defect. What is the most appropriate surgical treatment?

Explanation

For a locked posterior dislocation with an anteromedial head defect (reverse Hill-Sachs) involving 20-40% of the articular surface, a modified McLaughlin procedure is indicated. This involves transferring the lesser tuberosity and subscapularis tendon into the defect to prevent engagement.

Question 37

A 28-year-old construction worker falls from a height and sustains an inferior shoulder dislocation. On clinical presentation, his arm is hyperabducted, and his hand is resting behind his head.

Which of the following vascular injuries is most commonly associated with this specific dislocation pattern?

Explanation

The clinical picture describes luxatio erecta (inferior shoulder dislocation). This rare injury has the highest rate of associated axillary artery and axillary nerve injuries among all types of shoulder dislocations.

Question 38

Biomechanical studies have demonstrated that different bands of the glenohumeral ligaments act as primary restraints in varying shoulder positions. In which position is the anterior band of the inferior glenohumeral ligament (IGHL) the primary restraint to anterior humeral translation?

Explanation

The anterior band of the IGHL is the most critical stabilizer against anterior translation of the humeral head when the shoulder is positioned in 90 degrees of abduction and maximum external rotation.

Question 39

A 29-year-old competitive weightlifter presents with acute right shoulder pain and loss of the anterior axillary fold after attempting a heavy bench press. MRI confirms a complete pectoralis major rupture. Regarding the anatomy of the pectoralis major insertion, where does the sternocostal head attach relative to the clavicular head?

Explanation

The pectoralis major tendon twists 180 degrees before inserting. The sternocostal head inserts on the lateral lip of the bicipital groove proximal and deep to the insertion of the clavicular head.

Question 40

A 21-year-old collegiate volleyball player complains of vague posterior shoulder pain. Examination reveals isolated weakness in external rotation, with normal internal rotation and normal abduction strength. An MRI reveals a paralabral cyst. Where is the cyst most likely located?

Explanation

A cyst at the spinoglenoid notch compresses the terminal branch of the suprascapular nerve, causing isolated denervation of the infraspinatus (weak external rotation). Compression at the suprascapular notch would affect both the supraspinatus and infraspinatus.

Question 41

A 35-year-old male sustained a midshaft clavicle fracture 6 months ago, treated non-operatively in a sling. He now presents with persistent pain and motion at the fracture site. Radiographs confirm a non-union. Which of the following initial injury characteristics was the most significant risk factor for this outcome?

Explanation

The most significant risk factors for non-union in midshaft clavicle fractures are 100% displacement (lack of cortical contact), shortening greater than 2 cm, and severe comminution.

Question 42

A 24-year-old rugby player falls directly onto his shoulder and sustains an acute acromioclavicular (AC) joint separation. Radiographs reveal 150% superior displacement of the distal clavicle relative to the acromion. Which ligaments are completely disrupted in this Type III injury?

Explanation

In a Type III AC joint separation, both the acromioclavicular (AC) ligaments and the coracoclavicular (CC) ligaments (conoid and trapezoid) are completely torn, allowing the clavicle to displace superiorly by 100-250%.

Question 43

A 40-year-old male is struck from behind while skiing. He presents with severe chest pain, dyspnea, and a palpable void at the medial end of the right clavicle. What is the most appropriate next step in management?

Explanation

Posterior sternoclavicular dislocations are orthopedic emergencies due to the high risk of compression to the trachea, esophagus, and mediastinal vessels. A CT scan of the chest is critical to assess for these life-threatening injuries prior to any reduction attempts.

Question 44

A 55-year-old female presents with lateral scapular winging three weeks after undergoing a lymph node biopsy in the posterior triangle of her neck. She has difficulty elevating her arm above 90 degrees. Which nerve was most likely injured during the procedure?

Explanation

The spinal accessory nerve (CN XI) innervates the trapezius muscle and courses superficially through the posterior cervical triangle, making it vulnerable during biopsies. Injury leads to trapezius paralysis and lateral scapular winging.

Question 45

According to recent quantitative anatomic studies regarding the proximal humerus, which vessel provides the predominant blood supply to the humeral head, challenging historical teachings?

Explanation

While historically the arcuate branch of the anterior humeral circumflex artery was believed to be the main supply, modern studies (e.g., Hettrich et al.) demonstrate that the posterior humeral circumflex artery provides over 60% of the blood supply to the humeral head.

Question 46

A 26-year-old male presents with recurrent anterior shoulder instability but no evidence of a Bankart lesion on initial imaging. An MRI arthrogram is obtained, revealing extravasation of contrast inferiorly forming a classic "J-sign." What is the diagnosis?

Explanation

A Humeral Avulsion of the Glenohumeral Ligament (HAGL) is characterized by the "J-sign" on an MRI arthrogram, which represents contrast leaking inferiorly through the avulsed capsule at the anatomic neck of the humerus.

Question 47

A 33-year-old overhead athlete undergoes an arthroscopic labral repair. Post-operatively, he notes new-onset numbness over the lateral aspect of his deltoid. Which arthroscopic portal placement is most strongly associated with this specific iatrogenic nerve injury?

Explanation

The anterior inferior portal places the axillary nerve at risk due to its close proximity to the inferior capsular recess and axillary pouch. Injury causes numbness over the lateral deltoid (axillary nerve distribution).

Question 48

An 18-year-old baseball pitcher presents with deep shoulder pain and clicking. Examination reveals a positive active compression (O'Brien's) test. Diagnostic arthroscopy identifies a Type II SLAP tear. What defines a Type II SLAP lesion?

Explanation

A Type II SLAP tear is defined as pathological detachment of both the superior labrum and the origin of the long head of the biceps tendon from the superior glenoid. It is the most common type requiring surgical repair.

Question 49

A 28-year-old weightlifter feels a sudden pop in his shoulder while performing heavy bench presses. On physical examination, he demonstrates weakness in internal rotation and an inability to lift his hand away from his lower back against resistance. Which of the following tendons is most likely injured?

Explanation

The patient's mechanism of injury and positive Gerber lift-off test strongly indicate a subscapularis tendon tear. The subscapularis is the primary internal rotator of the shoulder and is heavily loaded during bench press exercises.

Question 50

A 22-year-old collegiate wrestler presents with a history of recurrent anterior shoulder dislocations. Advanced imaging demonstrates an engaging Hill-Sachs lesion and a 26% anterior glenoid bone loss. What is the most appropriate definitive surgical management?

Explanation

In the setting of critical anterior glenoid bone loss (typically >20-25%), soft tissue stabilization alone (Bankart repair) has an unacceptably high failure rate. A bony augmentation procedure, such as the Latarjet procedure (coracoid transfer), is indicated to restore glenoid width and provide a sling effect.

Question 51

A 45-year-old man presents to the emergency department complaining of severe right shoulder pain and an inability to rotate his arm outward following a generalized tonic-clonic seizure. Based on typical radiographic findings for this mechanism of injury, what is the most likely diagnosis?

Explanation

Seizures and electrical shocks classically cause posterior shoulder dislocations because the strong internal rotators overpower the external rotators. The arm is characteristically locked in internal rotation, and AP radiographs typically show the 'lightbulb sign'.

Question 52

An 18-year-old gymnast sustains an anterior shoulder dislocation. After successful closed reduction, she complains of decreased sensation over the lateral aspect of her deltoid muscle. Which of the following nerve roots primarily contributes to the injured nerve?

Explanation

The axillary nerve is the most commonly injured nerve in anterior shoulder dislocations, presenting with lateral deltoid numbness. The axillary nerve arises from the posterior cord of the brachial plexus and carries fibers primarily from the C5 and C6 nerve roots.

Question 53

During a posterior approach to the shoulder, the surgeon must carefully navigate the quadrangular space to avoid injury to the axillary nerve and posterior circumflex humeral artery. Which muscle forms the superior border of this anatomic space?

Explanation

The quadrangular space is bordered superiorly by the teres minor, inferiorly by the teres major, medially by the long head of the triceps, and laterally by the surgical neck of the humerus. It transmits the axillary nerve and posterior circumflex humeral vessels.

Question 54

A 30-year-old male sustains a severe hyperabduction injury to his shoulder. He presents to the trauma bay with his arm locked in an overhead position. Which complication is disproportionately associated with this specific type of shoulder dislocation compared to anterior dislocations?

Explanation

The patient has luxatio erecta (inferior shoulder dislocation), classically presenting with the arm held overhead. This injury has the highest rate of associated neurovascular compromise, particularly axillary artery injury and brachial plexus traction.

Question 55

In a patient with recurrent anterior shoulder instability, imaging reveals an engaging Hill-Sachs lesion with subcritical (10%) glenoid bone loss. The surgeon plans an arthroscopic Bankart repair. Which adjunctive procedure is most commonly performed to address the humeral head defect?

Explanation

Remplissage (filling the defect with the infraspinatus tendon and posterior capsule) is indicated for an engaging Hill-Sachs lesion when glenoid bone loss is subcritical (<20%). It prevents the defect from engaging the anterior glenoid rim during abduction and external rotation.

Question 56

A 12-year-old obese male presents with a two-week history of a limp and poorly localized thigh and knee pain. Radiographs reveal a slipped capital femoral epiphysis (SCFE). Which of the following represents the primary blood supply to the femoral head that is at risk of disruption in this condition?

Explanation

The medial femoral circumflex artery (MFCA) provides the primary blood supply to the femoral head in older children and adults. Disruption of the MFCA during a severe or unstable SCFE (or its treatment) can lead to avascular necrosis.

Question 57

A 45-year-old female presents with severe paresthesias in her right thumb, index, and middle fingers that consistently awaken her at night. Examination reveals profound thenar atrophy. Which muscle is typically innervated by the recurrent motor branch of the median nerve in this condition?

Explanation

The patient has severe carpal tunnel syndrome. The recurrent motor branch of the median nerve innervates the thenar muscles: opponens pollicis, abductor pollicis brevis, and the superficial head of the flexor pollicis brevis.

Question 58

A 60-year-old poorly controlled diabetic patient presents with a severely swollen, erythematous, but painless midfoot. Radiographs show extensive joint destruction, bone fragmentation, and subluxation. What is the primary underlying pathogenesis of this destructive joint disease?

Explanation

The presentation is classic for Charcot neuroarthropathy. The neurotraumatic theory posits that profound peripheral neuropathy leads to a loss of protective sensation, allowing repetitive microtrauma to cause progressive joint destruction.

Question 59

A 25-year-old male sustains a comminuted midshaft tibia fracture. Four hours post-admission, he develops severe calf pain out of proportion to the injury, exacerbated by passive toe extension. Which measured parameter is the most reliable threshold for indicating emergent fasciotomy?

Explanation

The Delta P (diastolic blood pressure minus intracompartmental pressure) is the most reliable indicator for acute compartment syndrome. A Delta P of less than 30 mmHg represents inadequate tissue perfusion and is an absolute indication for fasciotomy.

Question 60

A 6-year-old boy is brought to the clinic with an acute onset of right hip pain and a limp. He had a brief upper respiratory infection two weeks prior. He is afebrile, and his WBC, ESR, and CRP are within normal limits. Ultrasound demonstrates a small joint effusion. What is the most appropriate initial management?

Explanation

This presentation is highly characteristic of transient synovitis of the hip, a benign, self-limiting condition often following a viral illness. Because his inflammatory markers are normal (Kocher criteria negative), septic arthritis is unlikely, and NSAIDs with observation is the standard of care.

Question 61

A 35-year-old female falls on an outstretched hand and sustains a closed, displaced fracture of the distal third of the radial shaft along with a dislocation of the distal radioulnar joint (DRUJ). What is the eponymous classification for this specific injury pattern?

Explanation

A Galeazzi fracture is defined as a fracture of the distal third of the radius with an associated dislocation or subluxation of the distal radioulnar joint (DRUJ). It invariably requires open reduction and internal fixation in adults.

Question 62

A 55-year-old male presents to the emergency department with worsening lower back pain, bilateral lower extremity weakness, and saddle anesthesia. He reports recent episodes of urinary incontinence. Which of the following is the most appropriate immediate step in management?

Explanation

The patient is presenting with classic red flag symptoms of cauda equina syndrome (saddle anesthesia, bowel/bladder dysfunction, bilateral weakness). Emergent MRI of the lumbar spine is required to confirm the diagnosis and plan for immediate surgical decompression.

Question 63

During a posterior approach to the hip (Kocher-Langenbeck), the surgeon divides the short external rotators. Which specific tendinous structure is typically tagged and reflected posteriorly over the sciatic nerve to protect it during the procedure?

Explanation

During the posterior approach to the hip, the conjoined tendon of the obturator internus and the gemelli is tenotomized at its femoral insertion and reflected posteriorly. This creates a soft-tissue sling that protects the sciatic nerve from retractors during the operation.

Question 64

A 15-year-old male complains of a rapidly growing, painful mass around his distal femur. Radiographs display a destructive metaphyseal lesion with a 'sunburst' periosteal reaction and elevation of the periosteum forming a Codman triangle. What is the most likely diagnosis?

Explanation

Osteosarcoma is the most common primary malignant bone tumor in children and adolescents, typically occurring in the metaphysis of long bones. The 'sunburst' pattern and Codman triangle are classic aggressive radiographic features of this tumor.

Question 65

A 7-month-old infant is undergoing treatment with a Pavlik harness for developmental dysplasia of the hip (DDH). The mother notes the child is no longer actively extending the knee on the affected side. Upon examination, the quadriceps reflex is absent. Which nerve is most likely compressed by the harness?

Explanation

Hyperflexion of the hip in a Pavlik harness can lead to compression of the femoral nerve against the pelvic brim. This presents as a femoral nerve palsy, characterized by decreased active knee extension and loss of the patellar reflex.

Question 66

A 32-year-old female falls onto her outstretched arm, sustaining a complex elbow injury. The orthopedic surgeon describes the injury as the 'terrible triad' of the elbow. Which of the following distinct injury components define this triad?

Explanation

The 'terrible triad' of the elbow consists of a posterior elbow dislocation, a radial head fracture, and a coronoid fracture. It is notoriously difficult to manage due to severe resulting rotatory and varus/valgus instability.

Question 67

A 21-year-old football player sustains a non-contact pivoting injury to his knee. MRI reveals an isolated complete tear of the anterior cruciate ligament (ACL). When planning an anatomic reconstruction, the surgeon must identify the native femoral footprint of the ACL. Where is this located?

Explanation

The anterior cruciate ligament originates on the medial aspect of the lateral femoral condyle and inserts on the anterior intercondylar area of the tibia. Accurate placement of the femoral tunnel is critical for successful anatomic reconstruction.

Question 68

A 65-year-old female undergoes a total hip arthroplasty utilizing the direct anterior approach (Smith-Petersen interval). Postoperatively, she reports a distressing patch of numbness and burning pain over the anterolateral aspect of her proximal thigh. Which nerve was most likely stretched or injured during the exposure?

Explanation

The lateral femoral cutaneous nerve (LFCN) is highly vulnerable during the direct anterior approach to the hip due to its variable course near the anterior superior iliac spine (ASIS) and sartorius muscle. Injury results in anterolateral thigh numbness or meralgia paresthetica.

Question 69

A 22-year-old male rugby player presents with recurrent anterior shoulder instability after multiple prior dislocations. A CT scan of the shoulder reveals a 27% anterior glenoid bone loss. What is the most appropriate surgical management for this patient?

Explanation

Anterior glenoid bone loss greater than 20-25% is a critical indication for a bony augmentation procedure, such as the Latarjet procedure. Soft tissue stabilization alone (Bankart repair) in this setting has an unacceptably high failure rate.

Question 70

Which of the following muscles is most directly affected by the nerve most commonly injured during an anterior shoulder dislocation?

Explanation

The axillary nerve is the most commonly injured nerve in anterior shoulder dislocations. It provides crucial motor innervation to the deltoid and teres minor muscles.

Question 71

A 40-year-old male is evaluated in the emergency department for severe shoulder pain and a locked internal rotation deformity following an electrocution injury. An AP radiograph demonstrates the "lightbulb sign." Which of the following associated lesions is most likely present?

Explanation

The patient's presentation and the "lightbulb sign" indicate a posterior shoulder dislocation. This injury is frequently associated with a reverse Hill-Sachs lesion, which is an impaction fracture of the anteromedial aspect of the humeral head.

Question 72

A 28-year-old collegiate baseball pitcher presents with deep shoulder pain, mechanical clicking, and decreased throwing velocity. The pain is strongly reproduced with resisted forearm supination while the shoulder is flexed to 90 degrees. Which structure is most likely injured?

Explanation

The patient's presentation and positive O'Brien's or Yergason's test are consistent with a SLAP (Superior Labrum Anterior and Posterior) tear. These lesions involve the superior labrum and the origin of the long head of the biceps tendon.

Question 73

A 19-year-old female gymnast complains of bilateral shoulder pain and a subjective feeling of the shoulders "sliding out of place." Examination reveals a positive sulcus sign, positive apprehension at varying degrees, and generalized ligamentous laxity. What is the most appropriate initial management?

Explanation

The first-line treatment for multidirectional instability (MDI) is a prolonged course of physical therapy (minimum 6 months) emphasizing dynamic stabilization through rotator cuff and periscapular muscle strengthening.

Question 74

During a stabilization procedure for recurrent anterior shoulder instability, the surgeon elects to perform a "remplissage." This specific surgical technique is designed to address which of the following pathomorphological findings?

Explanation

The remplissage procedure involves tenodesis of the infraspinatus tendon and posterior capsule into a large, engaging Hill-Sachs defect. This converts it to an extra-articular lesion and prevents the defect from engaging the anterior glenoid rim during external rotation.

Question 75

A 65-year-old female falls onto her outstretched hand and sustains the injury depicted below.

Based on modern anatomic perfusion studies, which vessel provides the predominant blood supply to the humeral head that is at risk in complex proximal humerus fractures?

Explanation

While the anterior humeral circumflex artery provides the arcuate branch, recent quantitative studies demonstrate that the posterior humeral circumflex artery provides the predominant blood supply (up to 64%) to the humeral head and is critical in proximal humerus fractures.

Question 76

A 25-year-old mountain biker falls directly onto the point of his shoulder. Radiographs demonstrate a 150% superior displacement of the distal clavicle relative to the acromion with an increased coracoclavicular distance. Which classification and typical management strategy correspond to this injury?

Explanation

A Type V acromioclavicular (AC) joint injury is characterized by 100-300% superior displacement of the clavicle due to disruption of the CC ligaments and deltotrapezial fascia. Operative reconstruction is generally recommended for young, active patients to restore normal shoulder mechanics.

Question 77

A 55-year-old female presents with an insidious onset of progressive global shoulder stiffness and poorly localized pain over the past 4 months. She has profound restriction of active and passive external rotation. Which of the following systemic conditions is most strongly associated with the development and refractoriness of this disorder?

Explanation

Adhesive capsulitis (frozen shoulder) has a well-documented, strong association with endocrine disorders, most notably diabetes mellitus. Diabetic patients often have a more protracted clinical course, bilateral involvement, and greater resistance to conservative treatment.

Question 78

A 32-year-old male bodybuilder feels a sudden, painful "pop" in his anterior axilla while performing a heavy bench press. Examination reveals loss of the normal anterior axillary fold contour and pronounced weakness with resisted internal rotation. At which specific anatomical location does this rupture most commonly occur?

Explanation

Pectoralis major ruptures almost always occur at the tendinous insertion onto the lateral lip of the bicipital groove of the humerus. The mechanism typically involves forced eccentric loading, such as lowering the bar during a bench press.

Question 79

A 29-year-old elite volleyball player presents with posterior shoulder pain and paresthesias over the lateral aspect of the deltoid. An MRI demonstrates isolated denervation and atrophy of the teres minor. Compression of a neurovascular structure in the quadrilateral space is suspected. What are the correct borders of this anatomic space?

Explanation

The quadrilateral space is bordered by the teres minor (superior), teres major (inferior), long head of the triceps (medial), and surgical neck of the humerus (lateral). Compression of the axillary nerve in this space leads to Quadrilateral Space Syndrome.

Question 80

Three weeks following an acute anterior shoulder dislocation, a 60-year-old male complains of continued weakness and an inability to bring his hand to his abdomen. You suspect a concomitant rotator cuff injury. Which of the following physical examination maneuvers would most specifically isolate the affected tendon in this scenario?

Explanation

The Bear hug test, along with the belly-press and lift-off tests, evaluates the integrity of the subscapularis tendon. Subscapularis tears are a common structural injury in older patients following an anterior shoulder dislocation.

Question 81

A 74-year-old female sustains a complex 3-part proximal humerus fracture involving the surgical neck and greater tuberosity. Which of the following patient or radiographic factors most strongly supports the decision to perform a primary reverse total shoulder arthroplasty (RTSA) instead of open reduction internal fixation (ORIF)?

Explanation

Reverse total shoulder arthroplasty is highly indicated for complex proximal humerus fractures in elderly patients when there is pre-existing severe rotator cuff dysfunction or arthropathy, as ORIF or hemiarthroplasty would yield poor functional results.

Question 82

A 16-year-old male is tackled forcefully during a football game and presents with shortness of breath, dysphagia, and a palpable defect at the medial aspect of the left clavicle. Which imaging modality is considered the gold standard for evaluating this specific injury?

Explanation

The patient has a posterior sternoclavicular joint dislocation, a true orthopedic emergency due to potential compression of mediastinal structures (trachea, esophagus, great vessels). A CT scan is the gold standard for evaluating joint displacement and proximity to vital structures.

Question 83

A 35-year-old male cyclist sustains a completely displaced midshaft clavicle fracture. Which of the following initial radiographic or clinical characteristics is most highly predictive of nonunion if this fracture is treated non-operatively?

Explanation

Fracture shortening greater than 2 cm (or 100% displacement) in midshaft clavicle fractures is a significant biomechanical risk factor for nonunion. It is widely considered a relative indication for surgical fixation.

Question 84

A 62-year-old male is incidentally found to have an asymptomatic, full-thickness, 1.5 cm supraspinatus tear on an MRI ordered for a suspected cervical spine issue. What is the most likely natural history of this rotator cuff tear if observed conservatively over the next 2 to 3 years?

Explanation

Longitudinal studies demonstrate that asymptomatic full-thickness rotator cuff tears have a high probability of enlarging over time. Furthermore, approximately 50% will become clinically symptomatic within 2 to 3 years as they progress in size.

Question 85

A 22-year-old collegiate rugby player presents with recurrent anterior shoulder instability. He has had 5 dislocations over the past year. Advanced imaging reveals a 25% anterior glenoid bone loss. Which of the following surgical interventions is most appropriate to minimize his risk of recurrent dislocation?

Explanation

The open Latarjet procedure (coracoid transfer) is indicated for patients with recurrent anterior shoulder instability and significant glenoid bone loss, typically defined as greater than 20-25%. An arthroscopic Bankart repair alone in the setting of critical bone loss carries an unacceptably high failure rate.

Question 86

A 45-year-old male with a history of poorly controlled epilepsy presents with right shoulder pain following a generalized tonic-clonic seizure. Examination reveals the arm locked in internal rotation. A CT scan confirms a locked posterior shoulder dislocation with an associated reverse Hill-Sachs lesion involving 35% of the articular surface. What is the most appropriate surgical management?

Explanation

For posterior dislocations with an anteromedial humeral head defect (reverse Hill-Sachs) involving 20% to 40% of the articular surface, a modified McLaughlin procedure (transferring the subscapularis/lesser tuberosity into the defect) is indicated to restore stability. Arthroplasty is generally reserved for defects >40-50% or older patients with concurrent arthritis.

Question 87

A 68-year-old female sustains a 4-part proximal humerus fracture. According to the Hertel criteria, which of the following radiographic findings is the strongest predictor of humeral head ischemia?

Explanation

The Hertel criteria identify a metaphyseal head extension (calcar length) of <8 mm and a disrupted medial hinge (>2 mm) as the most reliable predictors of humeral head ischemia. These findings suggest profound disruption of the ascending branch of the anterior humeral circumflex artery and intraosseous collateral blood supply.

Question 88

A 65-year-old male presents with worsening left shoulder pain. Radiographs demonstrate severe primary glenohumeral osteoarthritis. A preoperative CT scan classifies the glenoid as a Walch B2 type. Which of the following morphological features characterizes a Walch B2 glenoid?

Explanation

The Walch B2 glenoid classification indicates an acquired biconcave glenoid with posterior wear and posterior subluxation of the humeral head. Recognizing this is critical during arthroplasty to correct version and prevent early eccentric loading and failure of the glenoid component.

Question 89

A 32-year-old male competitive weightlifter feels a sudden "pop" in his axilla while performing a heavy bench press. Examination demonstrates loss of the anterior axillary fold and weakness with internal rotation. He is diagnosed with a pectoralis major rupture. Which of the following best describes the anatomic footprint of the sternal head of the pectoralis major on the humerus?

Explanation

The pectoralis major tendon twists 180 degrees before inserting on the lateral lip of the bicipital groove. This twist causes the sternal head to insert deep and proximal to the clavicular head, making it more vulnerable to tearing during eccentric loading in a lengthened state.

Question 90

A 28-year-old male sustains a shoulder injury during a recreational wrestling match. Based on the likely diagnosis shown in the representative radiograph, which of the following is the most commonly associated nerve injury?

Explanation

The most common nerve injury associated with an anterior shoulder dislocation is an axillary nerve neuropraxia. Patients should be carefully evaluated for altered sensation over the lateral shoulder (regimental badge area) and weakness in the deltoid muscle.

Question 91

A 25-year-old cyclist falls directly onto his right shoulder. Clinical examination reveals profound superior prominence of the distal clavicle. Radiographs demonstrate the distal clavicle displaced superiorly by 150% relative to the acromion. Which of the following describes the injured structures in a Type V acromioclavicular (AC) joint separation?

Explanation

A Type V AC joint separation involves severe superior displacement (>100-300%) due to disruption of both the AC and CC ligaments, along with extensive stripping or tearing of the deltotrapezial fascia. This degree of instability generally warrants surgical reconstruction.

Question 92

A 74-year-old female presents with pseudoparalysis of the right shoulder and severe pain. Radiographs reveal an acromiohumeral interval of 3 mm and severe "bone-on-bone" arthritic changes. MRI confirms a massive, retracted rotator cuff tear with grade 4 fatty infiltration of the supraspinatus and infraspinatus. What is the most appropriate surgical intervention?

Explanation

Reverse total shoulder arthroplasty (RTSA) is the gold standard for rotator cuff tear arthropathy in an elderly patient with pseudoparalysis. It medializes and distalizes the center of rotation, recruiting the deltoid to elevate the arm despite the deficient rotator cuff.

Question 93

A 48-year-old female with insulin-dependent diabetes presents with a 4-month history of insidious onset right shoulder stiffness and pain. Radiographs are normal. Which physical examination finding is the hallmark diagnostic sign of adhesive capsulitis?

Explanation

The hallmark clinical finding of adhesive capsulitis is a profound, equal loss of both active and passive range of motion. Restriction of external rotation with the arm at the side (due to contracture of the coracohumeral ligament and anterior capsule) is particularly pathognomonic.

Question 94

A 19-year-old male involved in a high-speed motor vehicle collision presents to the trauma bay with severe chest pain, stridor, and dysphagia. Examination shows a palpable depression at the right medial clavicle. Standard AP chest radiographs are inconclusive. What is the most appropriate next step in management?

Explanation

This clinical presentation is highly suspicious for a posterior sternoclavicular dislocation, which can compromise the trachea, esophagus, or great vessels. A CT scan of the chest with IV contrast is the gold standard to evaluate the displacement and integrity of the mediastinal structures prior to any reduction attempts.

ABOS Part I Comprehensive Orthopedic Board Exam Review & Oral Exam Prep | Part 22166

ABOS Part I & AAOS OITE Orthopaedic Surgery Review: Clinical Cases & Exam Questions | Part 22139

Key Takeaway

ABOS Part I & AAOS OITE Orthopaedic Surgery Review: Clinical Cases & Exam Questions | Part 22139

Chapter Index