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1. General Principles & Basic Science MCQs

Practice Set 60 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 1181

Topic: 1. General Principles & Basic Science

Macrodactyly affects:

. Only bones
. Bones and fat
. Bones, fat, and nerves
. Bones, fat, nerves, and blood vessels
. Bones, fat, nerves, blood vessels, and tendons

Correct Answer & Explanation

. Bones, fat, and nerves

Explanation

Although this is controversial, the majority of surgeons believe that macrodactyly affects bones, fat, and nerves.

Question 1182

Topic: 1. General Principles & Basic Science

When ruptured, which portion of the scapholunate ligament leads to scaphoid-lunate diastasis:

. Distal
. Proximal
. Intermediate
. Dorsal
. Volar

Correct Answer & Explanation

. Dorsal

Explanation

The dorsal section of the scapholunate ligament is the strongest portion, requiring 300 N of load for failure. The volar (150 N) and intermediate portions (25 N to 50 N) contribute less to overall stability.

Question 1183

Topic: 1. General Principles & Basic Science

Which of the following radiographic views is not routinely used to diagnose scapholunate injury:

. Semisupination oblique view
. C lenched fist view
. Lateral view
. Anteroposterior (AP) view
. Oblique view

Correct Answer & Explanation

. Semisupination oblique view

Explanation

The semisupination oblique view is used to visualize the pisiform and pisotriquetral joint. The PA oblique and lateral views are the primary films used to diagnose scapholunate instability. The clenched fist view is used as a provocative view to bring out dynamic instability.

Question 1184

Topic: 1. General Principles & Basic Science

Which of the following treatments is not used for acute scapholunate ligament ruptures:

. Open repair with bone sutures
. Proximal row carpectomy
. C losed reduction and long arm cast
. Arthroscopically assisted reduction and pinning
. Open repair with suture anchors

Correct Answer & Explanation

. Proximal row carpectomy

Explanation

Proximal row carpectomy is a salvage procedure for chronic instability with focal radioscaphoid arthritis. Open repair with sutures through bone tunnels, open repair with suture anchors, and arthroscopically assisted reduction and pinning have been used successfully in acute cases.

Question 1185

Topic: Surgical Anatomy & Approaches

Which of the following is considered indicative of a scaphoid-lunate ligament tear on posteroanterior radiograph:

. Terry Thomas sign
. Volar intercalated segmental instability (VISI) pattern
. Spilled tea cup sign
. Watson-Jones scaphoid shift
. Dorsal intercalated segment instability (DISI) pattern

Correct Answer & Explanation

. Dorsal intercalated segment instability (DISI) pattern

Explanation

The VISI, DISI, and spilled tea cup signs are seen on lateral radiographs, whereas the Watson-Jones scaphoid shift test is a clinical sign. The classic pattern after scaphoid-lunate ligament injury is a DISI pattern as the lunate extends and the scaphoid flexes. The spilled tea cup sign is present in perilunate dislocations.

Question 1186

Topic: 1. General Principles & Basic Science

Horners syndrome includes all of the following except:

. Miosis
. Anhidrosis
. Enophthalmosis
. Exophthalmosis
. Diplopia

Correct Answer & Explanation

. Exophthalmosis

Explanation

Horners syndrome is caused by disruption of sympathetic innervation and is characterized by enophthalmosis, not exophthalmosis. Other symptoms include anhidrosis, miosis, and ptosis.

Question 1187

Topic: 1. General Principles & Basic Science
Axonotmesis involves injury to the:
. Epineurium
. Endoneurium
. Perineurium
. Axon
. Vasonervorum

Correct Answer & Explanation

. Axon

Explanation

Axonotmesis, as described in Seddon's classification, implies injury to the axon and myelin sheath. Neurotmesis involves injury to all three layers.

Question 1188

Topic: Biology, Genetics & Bone Healing

Denosumab is often utilized in the management of unresectable Giant Cell Tumor of bone. What is the specific mechanism of action of this medication?

. It binds to the RANK receptor on osteoclasts, inducing apoptosis.
. It binds directly to RANKL, preventing its interaction with the RANK receptor.
. It inhibits macrophage colony-stimulating factor (M-CSF) production.
. It binds to osteoprotegerin (OPG), increasing its circulating half-life.

Correct Answer & Explanation

. It binds directly to RANKL, preventing its interaction with the RANK receptor.

Explanation

Denosumab is a fully human monoclonal antibody that binds directly to the Receptor Activator of Nuclear factor Kappa-B Ligand (RANKL). This prevents RANKL from activating the RANK receptor on osteoclasts and giant cells, thereby inhibiting their function and bone resorption.

Question 1189

Topic: Biology, Genetics & Bone Healing

Which of the following transcription factors is considered the essential "master regulator" for the differentiation of mesenchymal stem cells into osteoblasts?

. SOX9
. RUNX2 (Cbfa1)
. PPAR-gamma
. MyoD

Correct Answer & Explanation

. RUNX2 (Cbfa1)

Explanation

RUNX2 (also known as Core-binding factor subunit alpha-1 or Cbfa1) is the master transcription factor for osteoblast differentiation. SOX9 regulates chondrogenesis, and PPAR-gamma drives adipogenesis.

Question 1190

Topic: Biology, Genetics & Bone Healing

During fracture healing via endochondral ossification, the production of Type X collagen in the fracture callus is primarily mediated by which of the following cell types?

. Proliferating chondrocytes
. Hypertrophic chondrocytes
. Osteoblasts
. Multinucleated osteoclasts
. Mesenchymal stem cells

Correct Answer & Explanation

. Hypertrophic chondrocytes

Explanation

Hypertrophic chondrocytes in the callus specifically express and produce Type X collagen. This structural protein facilitates the calcification of the cartilage matrix, a crucial step before invasion by blood vessels and osteoprogenitor cells.

Question 1191

Topic: 1. General Principles & Basic Science

According to the Sunderland classification of peripheral nerve injury, which of the following histological descriptions correctly defines a fourth-degree nerve injury?

. Disruption of myelin with intact axons
. Disruption of axons with intact endoneurium
. Disruption of axons and endoneurium with intact perineurium
. Disruption of axons, endoneurium, and perineurium with intact epineurium
. Complete physical transection of the nerve trunk

Correct Answer & Explanation

. Disruption of axons, endoneurium, and perineurium with intact epineurium

Explanation

In a Sunderland grade IV injury, all internal neural and supporting elements (axon, endoneurium, perineurium) are disrupted, leaving only the outermost epineurium intact. Spontaneous recovery is highly unlikely due to severe internal scarring.

Question 1192

Topic: 1. General Principles & Basic Science

A 35-year-old laborer sustains a severe laceration to his index finger requiring flexor tendon repair.

Which of the following pulley combinations is most critical to preserve or reconstruct to prevent biomechanical bowstringing?

. A1 and A3
. A2 and A4
. A3 and C1
. A1 and A5
. A4 and C2

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 and A4 pulleys insert directly onto the phalangeal shafts and are the most critical biomechanical pulleys. Preserving or reconstructing them is essential to prevent flexor tendon bowstringing and loss of digital motion.

Question 1193

Topic: 1. General Principles & Basic Science

Which of the following statements regarding ganglions is false:

. Surgery can lead to a decrease in range of motion.
. Ganglions are filled with mucinous fluid that does not transilluminate.
. Needle aspiration is diagnostic and therapeutic, although the rate of recurrence is high after this procedure.
. Volar ganglion may arise in relation to the radial artery.
. Ganglions may be multilobulated.

Correct Answer & Explanation

. Ganglions are filled with mucinous fluid that does not transilluminate.

Explanation

Transillumination is a hallmark of ganglions. Because of the location from which ganglia arise and the dissection performed during resection, a decrease in range of motion can be seen postoperatively. Needle aspiration is diagnostic and can be therapeutic, however, recurrence rates as high as 95% have been reported. Volar ganglia can often be intimately associated with the radial artery. Ganglia may often be multilobulated.

Question 1194

Topic: 1. General Principles & Basic Science

Management of a mucous cyst entails:

. Aspiration with injection of hyaluronidase
. Aspiration only
. Excision and resection of osteophytes
. Aspiration with injection of steroids
. Arthrodesis of the distal interphalangeal joint

Correct Answer & Explanation

. Excision and resection of osteophytes

Explanation

Treatment of mucous cysts, which are ganglions of the distal interphalangeal joint associated with osteoarthritic changes, entails excision of the cyst and osteophyte resection of fusion. Aspiration only or aspiration of the cyst with injection of hyaluronidase is not indicated or efficacious in the treatment of mucous cysts because the osteophyte must be addressed. Injection of steroids also fails to address the underlying cause of these cysts. Arthrodesis of the distal interphalangeal joint is not necessary in the treatment of typical mucous cysts.C orrect Answer: Excision and resection of osteophytes

Question 1195

Topic: 1. General Principles & Basic Science

All of the following are characteristic of hemangiomas except:

. 70% of hemangiomas are visible by 4 weeks of age
. 70% of hemangiomas regress by 7 years of age
. Hemangiomas are three times more common in woman than men
. All cavernous hemangiomas regress by 12 years of age
. None of the above

Correct Answer & Explanation

. None of the above

Explanation

Cavernous hemangiomas are noninvoluting hemangiomas and require surgical excision.

Question 1196

Topic: 1. General Principles & Basic Science

Regarding the management of web space abscess, which of the following statements is not true:

. Transverse incisions should be used.
. Wounds may be left open.
. Drains are often used following evacuation.
. Early motion must be encouraged.
. Thorough debridement of the dead muscle is required.

Correct Answer & Explanation

. Transverse incisions should be used.

Explanation

Transverse incisions can lead to contractures that limit finger abduction. Leaving wounds open allow for continued drainage. If preferred, closed suction drains can be used after closure of the wound. All devitalized tissue must be debrided and all signs of infection removed and irrigated copiously. Early motion is encouraged to prevent stiffness.

Question 1197

Topic: 1. General Principles & Basic Science
Meleney's infection is caused by:
. Streptococcus viridans
. Aerobic hemolytic staphylococci
. Microaerophilic non-hemolytic streptococci
. B & C
. Staphylococcus aureus

Correct Answer & Explanation

. B & C

Explanation

Aerobic hemolytic staphylococci and microaerophilic non-hemolytic streptococci synergistically act to produce Meleney's infection. Meleney's infection is a gangrenous infection that often results after a small injury. The infection is characterized by significant, rapid swelling with gangrenous changes.

Question 1198

Topic: Infection, Pharmacology & VTE

The most common pathogen for osteomyelitis of phalanges is:

. Staphylococcus aureus
. Streptococci
. Haemophilus influenzae
. Mix of gram-negative and gram-positive organisms
. Pasturella multocida

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common pathogen that causes osteomyelitis in the hand. Most cases of osteomyelitis in the hand are due to direct extension. Other pathogens can be found if there is a contaminated injury that penetrates directly into the bone. H. infuenza , mixed pathogens, and Pasturella multocida are less likely causes of osteomyelitis and are often caused by direct inoculation injuries or bites.

Question 1199

Topic: Infection, Pharmacology & VTE

The most common pathogen causing septic arthritis in the hand is:

. Staphylococcus aureus
. Streptococci
. Haemophilus influenzae
. Mix of gram-negative and gram-positive organisms
. Atypical mycobacterium

Correct Answer & Explanation

. Staphylococcus aureus

Explanation

Staphylococcus aureus is the most common pathogen that causes septic arthritis in the hand. The second most common pathogen is streptococcus species infections, which are often the result of trauma. Treatment includes incision and drainage with copius irrigation.

Question 1200

Topic: 1. General Principles & Basic Science

A 35-year-old woman is bitten on her left index finger by a snake in her backyard. Management of snake bites includes all of the following except:

. Keeping the patient emotionally and physically still
. Applying a tourniquet
. Identifying the snake
. Injecting antivenin locally based on recommended guidelines
. C all immediately for help

Correct Answer & Explanation

. Injecting antivenin locally based on recommended guidelines

Explanation

There are different snake bite protocols depending on the species of snake. However, common steps in all snake bite protocols include keeping the patient emotionally and physically still, calling for help immediately, applying a moderately tight tourniquet proximally to prevent further spread of venom, and capture or identification of the snake. Local injection of the antivenin in the fingers or toes is contraindicated.C orrect Answer: Injecting antivenin locally based on recommended guidelines

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