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1. General Principles & Basic Science MCQs

Practice Set 404 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 8061

Topic: Biology, Genetics & Bone Healing

An 80-year-old woman presents with acute, severe localized midthoracic back pain following a minor lifting incident 1 week ago. Neurologic exam is completely normal. Radiographs demonstrate an acute T8 osteoporotic compression fracture with a 20% loss of anterior height. What is the recommended initial management?

. Balloon kyphoplasty
. Percutaneous vertebroplasty
. Posterior spinal fusion T7-T9
. Pain management, early mobilization, and osteoporosis evaluation
. Rigid custom TLSO brace for 3 months

Correct Answer & Explanation

. Pain management, early mobilization, and osteoporosis evaluation

Explanation

The initial management for an acute, stable osteoporotic vertebral compression fracture without neurologic deficit is non-operative. This includes aggressive pain management, early mobilization to prevent deconditioning and pulmonary complications, and medical treatment of the underlying osteoporosis. Vertebral augmentation is generally reserved for patients who fail conservative management (typically after 3-6 weeks) or have intractable pain leading to hospitalization.

Question 8062

Topic: Infection, Pharmacology & VTE

In the management of pyogenic vertebral osteomyelitis, which of the following scenarios is an absolute indication for surgical intervention rather than treatment with prolonged intravenous antibiotics alone?

. Elevated C-reactive protein (CRP) after 2 weeks of antibiotics
. Progressive neurologic deficit
. Isolated severe back pain without instability
. Blood cultures positive for Methicillin-resistant Staphylococcus aureus (MRSA)
. Involvement of two adjacent vertebral bodies

Correct Answer & Explanation

. Progressive neurologic deficit

Explanation

The majority of pyogenic vertebral osteomyelitis cases can be managed successfully with image-guided biopsy followed by a prolonged course of culture-directed intravenous antibiotics. Absolute indications for surgical intervention include progressive neurologic deficit, spinal instability or significant deformity, an epidural abscess causing neurologic compromise, and failure of medical management despite appropriate targeted antibiotic therapy.

Question 8063

Topic: Physiology & Rehabilitation
A 40-year-old man is transported to the trauma center after a high-speed motorcycle collision. On physical examination, he has dense bilateral loss of motor function, as well as loss of pain and temperature sensation below the T10 dermatomal level. However, his proprioception, vibratory sense, and fine touch sensation remain intact in his lower extremities. Which of the following spinal cord injury syndromes does this presentation most accurately describe?
. Central cord syndrome
. Brown-Sรฉquard syndrome
. Anterior cord syndrome
. Posterior cord syndrome
. Conus medullaris syndrome

Correct Answer & Explanation

. Anterior cord syndrome

Explanation

This classic presentation describes Anterior Cord Syndrome, which results from injury to the anterior two-thirds of the spinal cord (frequently secondary to direct compression or anterior spinal artery territory ischemia). It is characterized by the bilateral loss of motor function (corticospinal tracts) and pain/temperature sensation (spinothalamic tracts) below the level of the injury, with the complete preservation of the dorsal columns (proprioception, vibration, and light touch).

Question 8064

Topic: 1. General Principles & Basic Science

The spring ligament complex is a critical static stabilizer of the medial longitudinal arch. Which portion of this complex is the thickest, provides the most biomechanical support to the talar head, and is most commonly torn in adult acquired flatfoot deformity?

. Inferior calcaneonavicular ligament
. Superomedial calcaneonavicular ligament
. Plantar aponeurosis
. Medial talocalcaneal ligament
. Bifurcate ligament

Correct Answer & Explanation

. Superomedial calcaneonavicular ligament

Explanation

The superomedial calcaneonavicular ligament is the thickest and most critical component of the spring ligament complex. It acts as a primary sling for the talar head and is frequently attenuated or torn in progressive flatfoot deformities.

Question 8065

Topic: Infection, Pharmacology & VTE

A diabetic patient with a neuropathic plantar ulcer under the first metatarsal head has confirmed deep osteomyelitis of the metatarsal head. Non-invasive vascular studies indicate adequate perfusion. What is the most appropriate definitive management?

. Total contact casting until ulcer closure
. 6 weeks of oral culture-directed antibiotics without surgery
. Surgical debridement/resection of the infected bone with culture-directed systemic antibiotics
. Below-knee amputation
. Hyperbaric oxygen therapy and local wound care

Correct Answer & Explanation

. Surgical debridement/resection of the infected bone with culture-directed systemic antibiotics

Explanation

In the presence of deep osteomyelitis and adequate vascular supply, surgical debridement or resection of the necrotic/infected bone is essential for source control, complemented by culture-directed antibiotics.

Question 8066

Topic: Surgical Anatomy & Approaches

A 42-year-old male requires surgery for severe insertional Achilles tendinopathy with a large retrocalcaneal exostosis (Haglund deformity) and prominent intratendinous calcification. Which surgical approach provides the best access for complete debridement and bony resection?

. Percutaneous tenotomy
. Endoscopic calcaneoplasty
. Central tendon-splitting approach with partial detachment
. Gastrocnemius recession alone
. Medial longitudinal release without tendon detachment

Correct Answer & Explanation

. Central tendon-splitting approach with partial detachment

Explanation

For severe insertional tendinopathy with large exostoses, a central tendon-splitting approach (often requiring detachment of up to 50% of the tendon) allows adequate visualization for debridement and exostectomy, followed by secure reattachment using suture anchors.

Question 8067

Topic: Infection, Pharmacology & VTE

A 58-year-old male with long-standing, poorly controlled diabetes mellitus presents with a swollen, warm, erythematous left foot. He denies trauma and has no open ulcers. Radiographs reveal fragmentation and periosteal reaction around the midfoot.

What is the most definitive imaging modality to differentiate an acute Charcot neuroarthropathy from osteomyelitis in the absence of a skin ulcer?

. Three-phase bone scan (Technetium-99m)
. Contrast-enhanced MRI
. Positron Emission Tomography (PET) scan
. Indium-111 labeled leukocyte scan combined with a Technetium-99m sulfur colloid marrow scan
. Serial plain radiographs over 4 weeks

Correct Answer & Explanation

. Indium-111 labeled leukocyte scan combined with a Technetium-99m sulfur colloid marrow scan

Explanation

Differentiating acute Charcot arthropathy from osteomyelitis is challenging, as both present with erythema, swelling, and radiographic destruction. While MRI is highly sensitive, it can be poorly specific in the acute phase because both conditions exhibit significant bone marrow edema. The most definitive functional imaging modality to differentiate the two is an Indium-111 labeled WBC scan combined with a Technetium-99m sulfur colloid bone marrow scan. Charcot causes marrow proliferation (matching positive uptake on both scans), whereas osteomyelitis suppresses marrow but accumulates WBCs (spatial mismatch).

Question 8068

Topic: Infection, Pharmacology & VTE

A 58-year-old male with poorly controlled type 2 diabetes and peripheral neuropathy presents with a red, hot, and swollen left foot. He denies any trauma. The skin is intact with no ulceration. Radiographs show osteopenia and early fragmentation of the navicular. To differentiate between acute Charcot neuroarthropathy and osteomyelitis, which of the following nuclear medicine imaging studies is considered the most specific?

. Three-phase Technetium-99m bone scan
. Indium-111 labeled white blood cell (WBC) scan combined with a Technetium-99m sulfur colloid marrow scan
. Gallium-67 citrate scan
. Fluorodeoxyglucose (FDG) PET scan
. Isolated Indium-111 labeled white blood cell (WBC) scan

Correct Answer & Explanation

. Indium-111 labeled white blood cell (WBC) scan combined with a Technetium-99m sulfur colloid marrow scan

Explanation

The combination of an Indium-111 WBC scan and a Technetium-99m sulfur colloid bone marrow scan is highly specific for differentiating osteomyelitis from Charcot neuroarthropathy. An isolated WBC scan can have false positives in Charcot due to normal marrow remodeling taking up WBCs. The sulfur colloid targets bone marrow; therefore, discordant uptake (WBC uptake without corresponding marrow uptake) confirms infection (osteomyelitis), whereas concordant uptake suggests sterile Charcot remodeling.

Question 8069

Topic: Infection, Pharmacology & VTE

A 55-year-old male with long-standing, poorly controlled type 2 diabetes presents with a unilaterally red, hot, and swollen foot. Radiographs demonstrate periarticular fragmentation, bony debris, and early subluxation at the midfoot tarsometatarsal joints. The skin is intact with no ulcerations, and laboratory inflammatory markers (ESR, CRP) are within normal limits. What is the most appropriate initial management?

. Intravenous antibiotics and emergent surgical debridement
. Immediate total contact casting and strict non-weight bearing
. Primary arthrodesis of the affected midfoot joints with rigid internal fixation
. Exostectomy of the impending bony prominences
. Below-knee amputation

Correct Answer & Explanation

. Immediate total contact casting and strict non-weight bearing

Explanation

This patient is presenting with acute Eichenholtz Stage 1 (Development/Fragmentation phase) Charcot neuroarthropathy. The absence of ulceration and normal inflammatory markers make acute infection unlikely, distinguishing it from osteomyelitis or septic arthritis. The gold standard of treatment in the acute, active inflammatory phase is rigid offloading and immobilization, most effectively achieved with a total contact cast (TCC) and non-weight bearing. Surgical reconstruction in the acute inflammatory phase carries high failure rates and is generally contraindicated unless severe instability threatens the soft tissue envelope.

Question 8070

Topic: Surgical Anatomy & Approaches

A 42-year-old male construction worker who smokes 1 pack per day falls from a ladder, sustaining a closed, displaced, intra-articular calcaneal fracture (Sanders Type II). Which of the following surgical approaches carries the lowest risk of wound complications for this patient?

. Extensile lateral approach
. Medial approach
. Sinus tarsi approach
. Plantar approach
. Combined medial and lateral approach

Correct Answer & Explanation

. Sinus tarsi approach

Explanation

The sinus tarsi approach is a minimally invasive lateral approach for the treatment of intra-articular calcaneal fractures. It has been shown to significantly reduce the risk of soft-tissue and wound healing complications compared to the traditional extensile lateral approach. It is particularly beneficial in high-risk patients such as smokers or diabetics, while providing adequate visualization for articular reduction in less complex fracture patterns like Sanders Type II.

Question 8071

Topic: Surgical Anatomy & Approaches

A surgeon is performing an open reduction and internal fixation of a complex capitellar fracture involving the trochlea. The surgical plan requires exposing the radiocapitellar joint. If the surgeon utilizes the Kaplan approach, which of the following describes the correct internervous/intermuscular interval?

. Between the extensor carpi radialis brevis and extensor digitorum communis
. Between the anconeus and extensor carpi ulnaris
. Between the brachioradialis and extensor carpi radialis longus
. Between the pronator teres and flexor carpi radialis
. Between the extensor digitorum communis and extensor carpi ulnaris

Correct Answer & Explanation

. Between the extensor carpi radialis brevis and extensor digitorum communis

Explanation

The Kaplan approach to the lateral elbow utilizes the interval between the extensor carpi radialis brevis (ECRB, innervated by the radial nerve) and the extensor digitorum communis (EDC, innervated by the posterior interosseous nerve). In contrast, the Kocher approach utilizes the interval between the anconeus (radial nerve) and the extensor carpi ulnaris (posterior interosseous nerve).

Question 8072

Topic: 1. General Principles & Basic Science

A 32-year-old male sustains a closed, distal-third spiral fracture of the humeral shaft (Holstein-Lewis fracture). On initial presentation, he has a complete radial nerve palsy. He is treated with functional bracing. Twelve weeks later, there is radiographic evidence of early bridging callus, but the patient still has no clinical or electromyographic (EMG) evidence of radial nerve recovery. What is the most appropriate next step in management?

. Continue observation for another 6 weeks
. Radial nerve exploration and possible repair
. Tendon transfers to restore wrist and finger extension
. Switch to open reduction and internal fixation
. Perform a sural nerve autograft immediately

Correct Answer & Explanation

. Radial nerve exploration and possible repair

Explanation

The initial management of a closed humeral shaft fracture with a primary radial nerve palsy is observation, as the vast majority are neuropraxias that will spontaneously recover. However, if there is no clinical or EMG evidence of nerve recovery by 12 weeks (3 months), the standard recommendation is surgical exploration of the radial nerve. This allows for neurolysis, direct repair, or grafting if the nerve is transected or entrapped within the fracture callus.

Question 8073

Topic: Surgical Anatomy & Approaches

A 62-year-old woman sustains a displaced 3-part proximal humerus fracture. The orthopaedic surgeon plans open reduction and internal fixation via a deltopectoral approach. To avoid iatrogenic injury, the surgeon must be mindful of the axillary nerve. Which of the following accurately describes the normal anatomic course of the axillary nerve?

. Passes through the triangular interval accompanied by the profunda brachii artery
. Travels anterior to the subscapularis muscle and exits via the triangular space
. Passes inferior to the shoulder capsule through the quadrilateral space with the posterior humeral circumflex artery
. Pierces the coracobrachialis muscle to innervate the anterior compartment of the arm
. Courses superior to the teres minor and medial to the long head of the triceps

Correct Answer & Explanation

. Travels anterior to the subscapularis muscle and exits via the triangular space

Explanation

The axillary nerve originates from the posterior cord of the brachial plexus. It courses anterior to the subscapularis muscle, then passes inferior to the shoulder capsule to exit posteriorly through the quadrilateral space, accompanied by the posterior humeral circumflex artery. The quadrilateral space is bounded by the teres minor (superior), teres major (inferior), long head of the triceps (medial), and humerus (lateral).

Question 8074

Topic: Surgical Anatomy & Approaches

A 32-year-old man sustained a closed midshaft humerus fracture and presents with an inability to extend his wrist or fingers. He is treated nonoperatively with a functional brace. At 3 months, his fracture shows progressive healing, but there is no clinical or electromyographic (EMG) evidence of radial nerve recovery. What is the most appropriate next step in management?

. Continue observation for another 3 months
. Nerve exploration and neurolysis
. Tendon transfers
. Open reduction and internal fixation of the humerus
. Radial nerve grafting

Correct Answer & Explanation

. Nerve exploration and neurolysis

Explanation

Observation of primary radial nerve palsy in closed humerus fractures is standard, as most resolve spontaneously. However, the lack of clinical or EMG signs of recovery by 3 to 4 months warrants surgical exploration to assess the nerve and perform neurolysis or repair as indicated.

Question 8075

Topic: Surgical Anatomy & Approaches

A 55-year-old male manual laborer undergoes an open subpectoral biceps tenodesis for partial tearing of the long head of the biceps tendon. Which of the following represents a known advantage of open subpectoral biceps tenodesis compared to an arthroscopic suprapectoral tenodesis?

. Complete removal of the biceps tendon from the bicipital groove
. Shorter overall surgical time
. Lower risk of postoperative stiffness
. Lower risk of musculocutaneous nerve injury
. Decreased incidence of postoperative 'Popeye' deformity

Correct Answer & Explanation

. Complete removal of the biceps tendon from the bicipital groove

Explanation

Open subpectoral tenodesis completely removes the long head of the biceps tendon from the bicipital groove. This effectively eliminates the groove as a potential source of persistent anterior shoulder pain, which can occur from tenosynovitis or hidden tendon lesions that might remain if a suprapectoral tenodesis is performed.

Question 8076

Topic: 1. General Principles & Basic Science

A 29-year-old competitive weightlifter feels a 'pop' in his anterior axilla while performing a heavy bench press. Examination reveals bruising over the anterior arm and axilla, and weakness with adduction and internal rotation. He is diagnosed with a pectoralis major rupture. Which portion of the pectoralis major tendon is under the greatest tension during the eccentric phase of the bench press, making it most susceptible to injury?

. The clavicular head
. The sternal head
. The abdominal head
. The inferior portion of the sternocostal head that inserts most proximally on the humerus
. The superior portion of the clavicular head that inserts most distally

Correct Answer & Explanation

. The inferior portion of the sternocostal head that inserts most proximally on the humerus

Explanation

The pectoralis major tendon twists 180 degrees before inserting on the humerus. The inferior fibers (sternocostal head) insert most proximally on the humerus, while the superior fibers (clavicular head) insert distally. During the eccentric phase of a bench press (arm extended, abducted, and externally rotated), the inferior fibers are stretched disproportionately and are under the greatest tension, making them the most frequently ruptured portion.

Question 8077

Topic: 1. General Principles & Basic Science

A 19-year-old male is brought to the emergency department after a severe tackle in a rugby match. He complains of chest pain, difficulty swallowing, and a feeling of fullness in his neck. Physical examination reveals a palpable depression over the medial aspect of the right clavicle. Radiographs and a subsequent CT scan confirm a posterior sternoclavicular joint dislocation. Which of the following anatomical structures is at the highest risk of injury in this setting?

. Brachiocephalic vein
. Subclavian artery
. Recurrent laryngeal nerve
. Internal jugular vein
. Vagus nerve

Correct Answer & Explanation

. Brachiocephalic vein

Explanation

Posterior sternoclavicular dislocations are considered orthopedic emergencies due to the close proximity of the joint to critical mediastinal structures. The most commonly injured or compressed structures in this scenario are the great vessels, specifically the brachiocephalic (innominate) vein, which lies directly posterior to the sternoclavicular joint. Other structures at risk include the trachea, esophagus, and subclavian vessels. Closed reduction should be performed urgently in the operating room with cardiothoracic surgery backup.

Question 8078

Topic: Surgical Anatomy & Approaches

During open reduction and internal fixation of a displaced 3-part proximal humerus fracture using a deltopectoral approach, the surgeon needs to carefully retract the deltoid and protect the axillary nerve. At what approximate distance from the lateral edge of the acromion does the axillary nerve typically traverse the deep surface of the deltoid?

. 2 to 3 cm
. 5 to 7 cm
. 9 to 11 cm
. 12 to 14 cm
. 15 to 17 cm

Correct Answer & Explanation

. 5 to 7 cm

Explanation

The axillary nerve travels through the quadrilateral space and courses anteriorly around the surgical neck of the humerus along the deep surface of the deltoid muscle. It typically lies approximately 5 to 7 cm distal to the lateral edge of the acromion. When performing surgery on the proximal humerus, especially via lateral approaches (such as the deltoid-splitting approach) or when placing retractor blades deep to the deltoid, it is critical to respect this anatomical 'safe zone' (less than 5 cm from the acromion) to avoid iatrogenic injury to the axillary nerve, which would result in catastrophic denervation of the anterior and middle deltoid.

Question 8079

Topic: 1. General Principles & Basic Science

A 28-year-old man sustains a laceration to the volar aspect of his index finger in Zone II, transecting both the flexor digitorum superficialis and profundus tendons. Primary repair of both tendons is performed using a 4-strand core suture and an epitendinous suture. To optimize functional outcome and minimize adhesion formation, which postoperative rehabilitation protocol is most appropriate?

. Immobilization in a static cast for 6 weeks, followed by active range of motion
. Early active motion protocol using a dorsal blocking splint
. Passive range of motion only for the first 8 weeks
. Immobilization in extension for 3 weeks
. Immediate unrestricted active range of motion without a splint

Correct Answer & Explanation

. Early active motion protocol using a dorsal blocking splint

Explanation

In Zone II flexor tendon repairs, the risk of adhesion formation within the fibro-osseous sheath is exceptionally high. Modern robust multi-strand repairs (4-strand or greater) allow for early active motion protocols (using a dorsal blocking splint to prevent excessive extension while permitting controlled active flexion). This significantly reduces adhesions, stimulates intrinsic tendon healing, and improves functional range of motion compared to prolonged immobilization.

Question 8080

Topic: Surgical Anatomy & Approaches

A 28-year-old man presents to the emergency department after a motor vehicle collision with a closed, significantly displaced spiral fracture of the middle third of the humerus. On initial physical exam, he has 5/5 wrist and finger extension. Following closed reduction and placement of a coaptation splint, he is completely unable to extend his wrist or fingers, and lacks sensation over the dorsal first web space. What is the most appropriate next step in management?

. Observe for 3 to 4 months with a functional brace
. Obtain a baseline electromyogram (EMG)
. Prescribe a wrist splint and begin physical therapy
. Immediate surgical exploration of the radial nerve and fracture fixation
. Obtain an MRI of the humerus to evaluate the nerve continuity

Correct Answer & Explanation

. Immediate surgical exploration of the radial nerve and fracture fixation

Explanation

Primary radial nerve palsy associated with a closed humeral shaft fracture is typically observed, as up to 90% of cases spontaneously recover. However, a secondary (iatrogenic) radial nerve palsy that develops strictlyafterclosed reduction is a strong indication for surgical exploration. This is because the nerve may be physically entrapped between the fracture fragments. Immediate surgical exploration of the radial nerve and internal fixation of the fracture is the most appropriate management.

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