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Question 841

Topic: 7. Hand and Wrist

In hypothenar hammer syndrome, digital ischemia most frequently affects the ring and small fingers. This occurs because emboli from the ulnar artery preferentially travel through which of the following structures?

. Deep palmar arch to the princeps pollicis artery
. Dorsal carpal arch to the dorsal metacarpal arteries
. Superficial palmar arch to the common digital arteries of the ulnar digits
. Anterior interosseous artery
. Radial indicis artery

Correct Answer & Explanation

. Superficial palmar arch to the common digital arteries of the ulnar digits


Explanation

The ulnar artery is the primary contributor to the superficial palmar arch. Emboli generated from an ulnar artery aneurysm or thrombus in Guyon's canal travel distally through this arch to the common digital arteries of the ring and small fingers.

Question 842

Topic: 7. Hand and Wrist

A 30-year-old pregnant patient presents with severe right hand pain and numbness. Examination reveals a positive Tinel's sign at the wrist. You are considering a local corticosteroid injection. Which of the following statements regarding this treatment in pregnancy is most accurate?

. It is strictly contraindicated in the third trimester due to the risk of premature labor.
. It requires the use of fluoroscopy to ensure proper needle placement.
. It provides effective symptomatic relief and has a well-established safety profile for the fetus.
. It is only effective if combined with high-dose oral corticosteroids.
. It permanently cures the condition, making postpartum symptoms impossible.

Correct Answer & Explanation

. It provides effective symptomatic relief and has a well-established safety profile for the fetus.


Explanation

Local corticosteroid injections are a safe and highly effective treatment for carpal tunnel syndrome in pregnancy. Systemic absorption is minimal, offering significant local relief with no proven adverse effects on the fetus.

Question 843

Topic: 7. Hand and Wrist

A 28-year-old primigravida at 32 weeks gestation presents with bilateral numbness in her radial three-and-a-half digits. Symptoms are worse at night. Which of the following best describes the expected natural history of her condition?

. Symptoms typically worsen immediately postpartum before resolving within 1 year.
. Symptoms generally resolve completely within a few weeks to months postpartum in the majority of patients.
. Permanent nerve damage is expected without third-trimester surgical release.
. Prolonged breastfeeding accelerates the resolution of symptoms.
. Spontaneous resolution rarely occurs without corticosteroid injection.

Correct Answer & Explanation

. Symptoms generally resolve completely within a few weeks to months postpartum in the majority of patients.


Explanation

Carpal tunnel syndrome in pregnancy typically presents in the third trimester due to fluid retention. Symptoms spontaneously resolve in the vast majority of patients within weeks to a few months postpartum.

Question 844

Topic: 7. Hand and Wrist

A 31-year-old woman at 36 weeks gestation with known carpal tunnel syndrome presents with progressive thenar atrophy and severe motor weakness. Conservative management with nocturnal splinting has failed. What is the most appropriate next step in management?

. Immediate postpartum carpal tunnel release
. Corticosteroid injection of the carpal tunnel
. Induction of labor followed by conservative management
. Open carpal tunnel release under local anesthesia
. Prescription of oral diuretics

Correct Answer & Explanation

. Open carpal tunnel release under local anesthesia


Explanation

While conservative management is the mainstay for CTS in pregnancy, progressive motor weakness and thenar atrophy are absolute indications for surgical decompression. Carpal tunnel release can be safely performed under local anesthesia during pregnancy.

Question 845

Topic: 7. Hand and Wrist

In hypothenar hammer syndrome, the ulnar artery is particularly susceptible to repetitive blunt trauma because it exits Guyon's canal and loses the protective cover of which of the following structures?

. Palmar carpal ligament
. Transverse carpal ligament
. Palmaris brevis muscle
. Volar carpal ligament
. Flexor carpi ulnaris tendon

Correct Answer & Explanation

. Palmaris brevis muscle


Explanation

The ulnar artery is vulnerable to injury distal to Guyon's canal where it lies superficial to the hook of the hamate. In this region, it loses the protective cover of the palmaris brevis muscle and the palmar aponeurosis.

Question 846

Topic: 7. Hand and Wrist

A 29-year-old pregnant patient (34 weeks gestation) presents with severe bilateral carpal tunnel syndrome that is refractory to splinting. A local corticosteroid injection is considered. Which of the following statements regarding corticosteroid injection for CTS during pregnancy is most accurate?

. It is contraindicated due to the risk of premature rupture of membranes.
. It provides significant transient relief and is considered safe for both mother and fetus.
. It carries a high risk of causing gestational diabetes.
. It is only effective if performed under ultrasound guidance.
. It is reserved exclusively for patients with thenar atrophy.

Correct Answer & Explanation

. It provides significant transient relief and is considered safe for both mother and fetus.


Explanation

Local corticosteroid injections are safe and highly effective for managing severe CTS in pregnancy when splinting fails. Systemic absorption is minimal, posing negligible risk to the fetus or to maternal glycemic control.

Question 847

Topic: 7. Hand and Wrist

Which of the following pathophysiological mechanisms is most directly responsible for the high incidence of carpal tunnel syndrome during the third trimester of pregnancy?

. Increased systemic relaxin leading to transverse carpal ligament laxity
. Fluid retention and increased extracellular fluid volume
. Hypertrophy of the flexor tenosynovium
. Gestational weight gain compressing the median nerve at the elbow
. Hypercoagulability leading to microvascular thrombosis of the vasa nervorum

Correct Answer & Explanation

. Fluid retention and increased extracellular fluid volume


Explanation

The primary cause of CTS in pregnancy is hormonally driven fluid retention and increased extracellular fluid volume. This leads to increased tissue pressure within the rigid carpal tunnel, which compromises median nerve microcirculation.

Question 848

Topic: Nerve & Tendon

A patient with hypothenar hammer syndrome complains of numbness and tingling in the ring and small fingers, in addition to cold intolerance. Which specific neural structure is most likely being compressed by an ulnar artery aneurysm in this condition?

. Deep motor branch of the ulnar nerve
. Superficial sensory branch of the ulnar nerve
. Palmar cutaneous branch of the median nerve
. Dorsal sensory branch of the ulnar nerve
. Recurrent motor branch of the median nerve

Correct Answer & Explanation

. Superficial sensory branch of the ulnar nerve


Explanation

An aneurysm of the ulnar artery in the hypothenar region typically compresses the adjacent superficial sensory branch of the ulnar nerve in Zone 3 of Guyon's canal. This leads to paresthesias in the volar aspect of the ring and small fingers.

Question 849

Topic: 7. Hand and Wrist

A 32-year-old woman developed carpal tunnel syndrome at 28 weeks gestation. She is now 6 months postpartum, exclusively breastfeeding, and continues to experience moderate nocturnal symptoms. What is the most likely physiological explanation for her delayed recovery?

. Irreversible axonal degeneration of the median nerve
. Elevated prolactin levels maintaining fluid retention
. Postpartum thyroiditis
. Undiagnosed gestational diabetes
. Inadequate splint usage during the third trimester

Correct Answer & Explanation

. Elevated prolactin levels maintaining fluid retention


Explanation

Prolonged breastfeeding is associated with a delay in the resolution of pregnancy-induced CTS. Elevated prolactin levels contribute to continued fluid retention and sustained pressure within the carpal tunnel.

Question 850

Topic: 7. Hand and Wrist

A 50-year-old construction worker presents with suspected hypothenar hammer syndrome. An Allen test is performed. Which of the following findings confirms an abnormal ulnar arterial supply?

. Immediate capillary refill upon release of the radial artery
. Pallor persisting for greater than 10 seconds after release of the ulnar artery
. Bounding radial pulse during ulnar occlusion
. Erythema of the entire hand within 3 seconds of ulnar release
. Pain in the hypothenar eminence during radial compression

Correct Answer & Explanation

. Pallor persisting for greater than 10 seconds after release of the ulnar artery


Explanation

During the Allen test, delayed capillary refill (typically >10 seconds) or persistent pallor after releasing the ulnar artery while keeping the radial artery occluded indicates impaired ulnar arterial flow, which is highly suggestive of HHS.

Question 851

Topic: 7. Hand and Wrist

A 50-year-old male presents to the emergency department with a high-pressure grease injection injury to his thumb, sustained 4 hours prior. He reports mild pain and swelling, but his neurovascular status appears intact, and he has full active range of motion. Based on the indications and contraindications outlined in the case, what is the most appropriate next step in management?

. A. Initiate broad-spectrum oral antibiotics and observe for 24 hours, given the mild symptoms.
. B. Perform immediate surgical exploration and debridement, regardless of mild symptoms.
. C. Obtain an MRI to delineate the extent of soft tissue involvement before deciding on surgery.
. D. Apply a static splint in a position of safety and refer for outpatient hand therapy.
. E. Administer corticosteroids to reduce inflammation and prevent fibrosis.

Correct Answer & Explanation

. B. Perform immediate surgical exploration and debridement, regardless of mild symptoms.


Explanation

Correct Answer: BExplanation:The case unequivocally states under 'Indications for Surgical Intervention' that 'All suspected or confirmed high-pressure injection injuries' are a 'universal indication' for 'Primary Surgical Debridement (Urgent/Emergent).' It further emphasizes, 'Even in asymptomatic cases with a clear history of HPII, surgical exploration is indicated due to the deceptive nature of the injury and the high risk of delayed necrosis.' The time elapsed (4 hours) is well within the critical window for urgent intervention (ideally within 6 hours).A. Initiate broad-spectrum oral antibiotics and observe for 24 hours, given the mild symptoms:This is incorrect. The case stresses that HPIIs are deceptive and require immediate surgical intervention, not observation, even with mild symptoms. IV antibiotics are indicated, but not as a substitute for surgery.C. Obtain an MRI to delineate the extent of soft tissue involvement before deciding on surgery:While MRI can be helpful, the case states it 'should not delay urgent surgery.' The decision for surgery is based on the diagnosis of HPII, not on the extent shown by MRI.D. Apply a static splint in a position of safety and refer for outpatient hand therapy:This is incorrect. HPIIs are surgical emergencies. Non-operative management is not indicated for the acute phase.E. Administer corticosteroids to reduce inflammation and prevent fibrosis:The case notes that the use of corticosteroids is 'controversial' and 'Current guidelines generally do not recommend routine prophylactic corticosteroids.' They are not the primary or immediate management step.

Question 852

Topic: 7. Hand and Wrist

A 40-year-old mechanic sustained a high-pressure diesel fuel injection injury to his ring finger 8 months ago. He underwent initial debridement and has since completed an intensive 6-month hand therapy program, including dynamic splinting and scar management. Despite these efforts, he presents with a persistent 45-degree DIP joint flexion contracture that significantly impairs his ability to perform fine motor tasks. Radiographs show no significant joint destruction. Based on the case, what is the most appropriate next step in his management?

. A. Continue with another 3 months of intensive hand therapy and splinting.
. B. Consider DIP joint arthrodesis in a functional position.
. C. Perform surgical tenolysis of the FDP tendon and volar plate release/capsulotomy.
. D. Initiate a course of oral corticosteroids to reduce residual inflammation.
. E. Recommend hyperbaric oxygen therapy to improve tissue remodeling.

Correct Answer & Explanation

. C. Perform surgical tenolysis of the FDP tendon and volar plate release/capsulotomy.


Explanation

Correct Answer: CExplanation:The case, under 'Secondary Surgical Management (for Established Contracture)' and 'Flexion Contracture,' states: 'If the FDP tendon is adherent, an extensive tenolysis is performed... If the volar plate and joint capsule are scarred and shortened, a volar plate release (often requiring resection of a portion) and anterior capsulotomy are performed to restore extension.' This patient has a significant, refractory flexion contracture (45 degrees) after extensive conservative management, with no joint destruction, making soft tissue release the indicated procedure.A. Continue with another 3 months of intensive hand therapy and splinting:The case indicates that surgical intervention for established contracture is considered after 'Failure of intensive non-operative therapy (typically >3-6 months).' This patient has already completed 6 months of intensive therapy, suggesting further conservative management is unlikely to be effective.B. Consider DIP joint arthrodesis in a functional position:Arthrodesis is described as a salvage procedure for 'severe, intractable contractures with significant joint destruction or pain.' The patient's radiographs show no significant joint destruction, making soft tissue release a more appropriate initial surgical option to preserve motion.D. Initiate a course of oral corticosteroids to reduce residual inflammation:The use of corticosteroids is controversial and generally not recommended for established contractures, especially after the acute inflammatory phase has subsided.E. Recommend hyperbaric oxygen therapy to improve tissue remodeling:HBO is considered an adjunct therapy, primarily for acute tissue salvage, and its role in established contracture remodeling is not a primary recommendation.

Question 853

Topic: 7. Hand and Wrist

Following surgical debridement for a high-pressure injection injury to the DIP joint, a patient is in the intermediate phase of rehabilitation (Week 4). The hand therapist notes a persistent flexion contracture of 25 degrees at the DIP joint. Based on the 'Post-Operative Rehabilitation Protocols' and 'Key Principles for DIP Joint Contracture Prevention' in the case, which intervention is most appropriate to address this developing contracture?

. A. Initiate forceful passive manipulation of the DIP joint to break adhesions.
. B. Discontinue all splinting to encourage natural movement.
. C. Implement dynamic extension splinting or static progressive splinting.
. D. Refer for immediate surgical tenolysis and capsulotomy.
. E. Prescribe a period of complete immobilization to allow tissues to heal fully.

Correct Answer & Explanation

. C. Implement dynamic extension splinting or static progressive splinting.


Explanation

Correct Answer: CExplanation:Under 'Intermediate Phase (Weeks 2-6)' and 'Progressive Splinting,' the case states: 'Dynamic Splinting: Continue dynamic extension splinting for flexion contractures, with adjustable outriggers to apply gentle, constant stretch.' It also mentions 'Static Progressive Splinting: Utilize splints that allow for gradual, incremental adjustments to increase the stretch on the contracted structures.' These methods apply 'Sustained Low-Load Stretch,' which is a key principle for contracture prevention and management.A. Initiate forceful passive manipulation of the DIP joint to break adhesions:The case explicitly warns against this: 'Avoid forceful manipulation which can cause re-injury or trigger CRPS.'B. Discontinue all splinting to encourage natural movement:This is incorrect. Splinting, particularly dynamic or static progressive splinting, is crucial in the intermediate phase to address developing contractures.D. Refer for immediate surgical tenolysis and capsulotomy:Surgical intervention for established contracture is typically considered after 'Failure of intensive non-operative therapy (typically >3-6 months).' At Week 4, non-operative measures like splinting are the primary approach.E. Prescribe a period of complete immobilization to allow tissues to heal fully:The case emphasizes 'Early Mobilization' as the 'single most important factor' and states that 'Prolonged immobilization is cited as a major contributor to stiffness and contracture development.'

Question 854

Topic: Nerve & Tendon
A 5-year-old girl falls onto an outstretched hand and sustains a minimally displaced (<2 mm) lateral condyle fracture of the humerus. Which of the following represents the most significant long-term complication if this fracture goes on to nonunion?
. Median nerve palsy
. Cubitus varus
. Tardy ulnar nerve palsy
. Volkmann ischemic contracture
. Anterior interosseous nerve palsy

Correct Answer & Explanation

. Tardy ulnar nerve palsy


Explanation

Nonunion of a lateral condyle fracture typically leads to a progressive cubitus valgus deformity. Over time, this valgus angulation chronically stretches the ulnar nerve, resulting in tardy ulnar nerve palsy.

Question 855

Topic: 7. Hand and Wrist

A 22-year-old male sustains a fracture-dislocation of the thumb carpometacarpal joint. Radiographs show a small volar-ulnar base fragment of the first metacarpal remaining articulated with the trapezium. Which muscle is primarily responsible for the proximal and dorsal displacement of the main metacarpal shaft?

. Abductor pollicis longus
. Abductor pollicis brevis
. Flexor pollicis longus
. Adductor pollicis
. Extensor pollicis brevis

Correct Answer & Explanation

. Abductor pollicis longus


Explanation

In a Bennett fracture, the volar oblique ligament retains the small volar-ulnar fragment in its anatomic position. The abductor pollicis longus (APL) acts as the primary deforming force, pulling the main metacarpal shaft proximally, dorsally, and radially.

Question 856

Topic: 7. Hand and Wrist

A 25-year-old sustains a transverse fracture of the proximal phalanx shaft of the long finger. What is the characteristic deformity of this fracture, and which structures are responsible?

. Apex dorsal angulation due to the intrinsic muscles and central slip
. Apex volar angulation due to the interosseous muscles and central slip
. Apex radial angulation due to the lumbricals
. Apex ulnar angulation due to the adductor aponeurosis
. Pure shortening with no angulation due to flexor digitorum profundus tension

Correct Answer & Explanation

. Apex volar angulation due to the interosseous muscles and central slip


Explanation

Proximal phalanx fractures typically deform with apex volar angulation. The intrinsic (interosseous) muscles pull the proximal fragment into flexion, while the central slip extends the distal fragment.

Question 857

Topic: 7. Hand and Wrist

In cases of high-pressure injection injuries to the hand, a delay in definitive surgical debridement beyond what timeframe is most strongly associated with a significantly increased risk of amputation?

. 2 hours
. 6 hours
. 10 hours
. 24 hours
. 48 hours

Correct Answer & Explanation

. 10 hours


Explanation

Clinical studies show that a delay in wide surgical debridement of more than 10 hours from the time of a high-pressure injection injury significantly increases the risk of digital amputation. Early decompression and debridement are critical regardless of the injected substance.

Question 858

Topic: 7. Hand and Wrist

Which of the following injected materials is associated with the highest risk of eventual amputation in high-pressure injection injuries (HPII) to the hand?

. Grease
. Oil-based paint solvents
. Water
. Hydraulic fluid
. Air

Correct Answer & Explanation

. Oil-based paint solvents


Explanation

The type of material injected is the most significant prognostic factor in HPII. Oil-based paint solvents and thinners cause a severe, immediate inflammatory response and tissue necrosis, leading to amputation rates as high as 60-80%.

Question 859

Topic: Nerve & Tendon

A 5-year-old boy is diagnosed with a displaced lateral condyle fracture of the humerus. If this fracture is managed non-operatively and goes on to nonunion, what is the classic long-term complication?

. Cubitus varus and median nerve palsy
. Cubitus valgus and tardy ulnar nerve palsy
. Cubitus varus and tardy ulnar nerve palsy
. Cubitus valgus and radial nerve palsy
. Joint stiffness with severe heterotopic ossification

Correct Answer & Explanation

. Cubitus valgus and tardy ulnar nerve palsy


Explanation

A nonunion of a pediatric lateral condyle fracture typically results in progressive cubitus valgus. Over time, this valgus deformity stretches the ulnar nerve, leading to tardy ulnar nerve palsy.

Question 860

Topic: 7. Hand and Wrist

A 25-year-old sustains a transverse fracture of the proximal phalanx shaft, which presents with apex-volar angulation. Which distinct deforming forces are responsible for this classic fracture pattern?

. Interossei flexing the proximal fragment and central slip extending the distal fragment
. Lumbricals extending the proximal fragment and FDS flexing the distal fragment
. Extensor digitorum communis extending the proximal fragment and FDP flexing the distal fragment
. Interossei extending the proximal fragment and central slip flexing the distal fragment
. Flexor digitorum superficialis flexing the proximal fragment and EDC extending the distal fragment

Correct Answer & Explanation

. Interossei flexing the proximal fragment and central slip extending the distal fragment


Explanation

In a proximal phalanx shaft fracture, the intrinsic muscles (interossei) flex the proximal fragment via their insertion on the base, while the central slip of the extensor mechanism extends the distal fragment, creating an apex-volar deformity.