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7. Hand and Wrist MCQs

Practice Set 103 of 266

This practice set contains high-yield board review questions covering key concepts in 7. Hand and Wrist. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2041

Topic: 7. Hand and Wrist
Figures 42a and 42b show the radiographs of a 20-year-old man who sustained a hyperextension injury to his little finger. Multiple attempts at closed reduction have been unsuccessful. Management should now consist of:
. external traction.
. open reduction and internal stabilization.
. repeat closed reduction under general anesthesia.
. open reduction.
. percutaneous pin fixation in the current position.

Correct Answer & Explanation

. open reduction.

Explanation

The radiographs show a complex dislocation of the little finger metacarpophalangeal joint. This is characterized by obvious dislocation on the AP and lateral views and a type of bayonet apposition best visualized on the lateral view. Irreducibility of this injury is caused by displacement of the volar plate that has been traumatically avulsed from its origin on the metacarpal, with subsequent displacement into the metacarpophalangeal joint. This abnormal position of the volar plate causes irreducibility that can be corrected only by open reduction. This can be effected either by dorsal or palmar approaches.

Question 2042

Topic: 7. Hand and Wrist

A 14-year-old boy sustained a 100% displaced distal radius Salter-Harris type II fracture. Neurologic examination demonstrates normal motor examination and two-point discrimination. He undergoes fracture reduction to the anatomic position with the application of a long arm cast. Postreduction he reports increasing hand and wrist pain with diminution of two-point discrimination to 10 mm over the index and middle fingers over the next several hours after surgery. The cast is bivalved and the padding released relieving all external pressure over the arm. Reevaluation reveals increasing sensory deficit over the affected area. What is the next most appropriate management intervention?

. Cast removal and measurement of carpal canal pressure
. Immediate carpal tunnel release and pinning of the fracture
. Continued observation
. Surgical reduction and pinning of the fracture
. Electromyography/nerve conduction velocity studies

Correct Answer & Explanation

. Immediate carpal tunnel release and pinning of the fracture

Explanation

The patient has an evolving acute carpal tunnel syndrome. Initial management for this injury is to relieve all external pressure that may elevate the neural compression. Surgical decompression of the median nerve at the carpal tunnel is the optimal intervention. Further nonsurgical interventions (cast removal or further bivalving) are insufficient to alleviate the neural compression. Waters PM, Mih AD: Fractures of the distal radius and ulna, in Beaty JH, Kasser JR (eds): Fractures in Children, ed 6. Philadelphia, PA, Lippincott, 2006, p 361.

Question 2043

Topic: Wrist & Carpus

An otherwise healthy 26-year-old woman is involved in a high speed motor vehicle accident and sustains the injury shown in Figure 54 to her dominant right arm. Appropriate treatment of this injury complex includes

General Orthopedics Board Review 2026: High-Yield MCQs (Set 4) - Figure 43

. plating of the radial shaft fracture and open repair of the triangular fibrocartilage complex.
. open reduction and internal fixation of the radius and ulna.
. plating of the radius with closed reduction and evaluation of the distal radioulnar joint (DRUJ).
. closed reduction of the radius and DRUJ.
. plating of the radius and pinning of the DRUJ in pronation.

Correct Answer & Explanation

. plating of the radius with closed reduction and evaluation of the distal radioulnar joint (DRUJ).

Explanation

This Galeazzi fracture is an injury that requires surgical treatment in an adult. The algorithm includes anatomic reduction of the radial shaft and closed reduction of the DRUJ with assessment of stability. If the DRUJ remains unstable, supination of the wrist may reduce the DRUJ. If not, either open or closed reduction with pinning is undertaken. The closer the radius fracture is to the DRUJ, the more likely it is to be unstable.

Question 2044

Topic: 7. Hand and Wrist

A 40-year-old construction worker presents with chronic wrist pain and weakness following a fall onto an outstretched hand 6 months ago. Radiographs demonstrate a scapholunate gap of 4mm and a dorsal intercalated segment instability (DISI) deformity. MRI confirms complete scapholunate ligament rupture.

Given the chronic nature and significant instability, what is the most appropriate surgical intervention to stabilize the wrist and preserve function?

. Primary scapholunate ligament repair.
. Scaphotrapeziotrapezoid (STT) fusion.
. Four-corner fusion (capitate-hamate-triquetrum-lunate).
. Scaphoid excision and four-corner fusion.
. Radial styloidectomy.

Correct Answer & Explanation

. Scaphoid excision and four-corner fusion.

Explanation

This patient presents with chronic scapholunate (SL) dissociation, characterized by a persistent scapholunate gap (>3mm), a dorsal intercalated segment instability (DISI) deformity, and a complete ligament rupture. The chronic nature (6 months post-injury) indicates that primary repair is unlikely to be successful due to tissue degradation and retraction.Option A (Primary scapholunate ligament repair) is indicated for acute, reducible scapholunate dissociations (typically within 3 weeks of injury) before chronic changes develop.Option B (Scaphotrapeziotrapezoid (STT) fusion) is a limited wrist fusion, which can be considered for chronic SL instability, but often leads to stiffness and may not be sufficient to address the DISI deformity, especially with a complete rupture.Option C (Four-corner fusion) involves fusing the capitate, hamate, triquetrum, and lunate. While it stabilizes the lunate and triquetrum, it does not address the degenerated scaphoid directly. It is often performedwithscaphoid excision to treat scapholunate advanced collapse (SLAC) wrist, a late consequence of chronic SL dissociation, to prevent further collapse and pain by removing the damaged scaphoid and fusing the remaining carpal bones.Option D (Scaphoid excision and four-corner fusion) is considered the gold standard treatment for symptomatic chronic scapholunate dissociation with early degenerative changes (SLAC wrist stage I or II). The scaphoid, which has lost its stable connection to the lunate and is subject to abnormal forces, is excised to eliminate its impingement, and the remaining carpal bones (capitate, hamate, triquetrum, lunate) are fused to provide stability and pain relief while preserving a reasonable range of motion. This approach directly addresses both the instability and the degenerative changes caused by the abnormal kinematics.Option E (Radial styloidectomy) might be part of an overall procedure in SLAC wrist to address impingement between the scaphoid and radial styloid, but it is not a standalone treatment for the primary instability.

Question 2045

Topic: 7. Hand and Wrist

A 30-year-old male sustains a high-energy fall onto an outstretched hand, resulting in a perilunate dislocation. Post-reduction radiographs show an anatomical reduction of the lunate with respect to the radius, but the capitate remains dorsally displaced relative to the lunate.

What is the most accurate term for this specific post-reduction radiographic appearance, indicating persistent instability?

. Scapholunate dissociation.
. Lunate dislocation.
. Capitolunate dissociation.
. Proximal carpal row instability.
. Midcarpal instability.

Correct Answer & Explanation

. Capitolunate dissociation.

Explanation

The scenario describes a perilunate dislocation where initial reduction returns the lunate to its normal position relative to the radius, but the capitate remains dislocated (dorsally displaced) relative to the lunate. This is a classic description of a capitolunate dissociation, also known as a dorsal trans-scaphoid or trans-triquetral perilunate fracture-dislocation if associated fractures are present, or simply persistent capitolunate instability after perilunate reduction.Option A (Scapholunate dissociation) involves disruption of the scapholunate ligament, leading to a gap between the scaphoid and lunate and often a DISI deformity. While a perilunate injury often involves scapholunate ligament disruption, the specific finding described post-reduction is capitate-lunate incongruity.Option B (Lunate dislocation) refers to the lunate itself being dislocated (typically volar) from both the radius and the capitate, forming a 'spilled teacup' sign on a lateral X-ray. The question states the lunate is reduced relative to the radius.Option C (Capitolunate dissociation) precisely describes the condition where the capitate and lunate are no longer articulating correctly, despite the lunate being reduced to the radius. This implies persistent instability in the midcarpal joint.Option D (Proximal carpal row instability) is a broad term that encompasses various instabilities within the proximal carpal row (e.g., scapholunate, lunotriquetral dissociation). While the described injury is a form of carpal instability, 'capitolunate dissociation' is more specific to the post-reduction radiographic finding.Option E (Midcarpal instability) is also a broad term referring to instability between the proximal and distal carpal rows. Capitolunate dissociation is a specific manifestation of persistent midcarpal instability following a perilunate injury. However, 'capitolunate dissociation' is the most accurate and descriptive term for thespecific radiographic findingof the capitate remaining displaced relative to the lunate after reduction of the lunate-radial articulation.

Question 2046

Topic: 7. Hand and Wrist

A 35-year-old painter presents with chronic ulnar-sided wrist pain, particularly with gripping and rotational movements. Physical examination reveals tenderness over the triquetrum and lunate, a positive ulnar snuffbox test, and painful clicking. Radiographs, including specialized views, show widening of the scapholunate interval and a Terry Thomas sign.

What is the MOST likely diagnosis and initial management strategy?

. Triangular Fibrocartilage Complex (TFCC) tear; surgical debridement.
. Pisotriquetral arthritis; corticosteroid injection.
. Scapholunate (SL) dissociation; arthroscopic repair of the ligament.
. Extensor Carpi Ulnaris (ECU) tendonitis; wrist immobilization.
. Lunotriquetral (LT) dissociation; dorsal capsulodesis.

Correct Answer & Explanation

. Scapholunate (SL) dissociation; arthroscopic repair of the ligament.

Explanation

The clinical presentation with ulnar-sided pain, clicking, and tenderness, combined with radiographic findings of a widened scapholunate interval (Terry Thomas sign), is classic for scapholunate (SL) dissociation. This injury represents a disruption of the scapholunate ligament, leading to carpal instability. Initial management for acute, reducible SL dissociation often involves arthroscopic repair of the ligament. Chronic or irreducible dissociations may require more complex reconstructive procedures (e.g., tenodesis). TFCC tears typically present with more localized ulnar-sided pain and mechanical symptoms but do not show the characteristic scapholunate widening. Pisotriquetral arthritis is less common and doesn't explain the radiographic findings. ECU tendonitis is an inflammatory condition, not an instability. LT dissociation presents similarly but affects the lunotriquetral interval and biomechanics differently, and the Terry Thomas sign is specific to SL dissociation.

Question 2047

Topic: 7. Hand and Wrist

A 28-year-old male falls from a ladder onto an outstretched hand, sustaining a high-energy wrist injury. Physical examination reveals a swollen, deformed wrist with significant pain and limited range of motion. Lateral radiographs of the wrist are obtained and show the following.

The radiographs confirm a dorsal perilunate dislocation. What is the MOST appropriate initial closed reduction maneuver for this injury?

. Gentle traction with the wrist in full flexion.
. Traction with the wrist in neutral, followed by radial deviation.
. Strong traction with the wrist in extension, followed by flexion and direct lunate pressure.
. Direct manual pressure on the dorsum of the hand to push the carpus volar.
. Immediate open reduction given the high energy mechanism.

Correct Answer & Explanation

. Strong traction with the wrist in extension, followed by flexion and direct lunate pressure.

Explanation

The classic closed reduction maneuver for a dorsal perilunate dislocation involves applying strong longitudinal traction to the hand while the wrist is held in extension. This maneuver, often referred to as 'ligamentotaxis,' helps to disimpact the carpus and opens the joint space. Once disimpacted, the wrist is gently flexed, and direct pressure is applied over the displaced lunate (volarly) or the capitate (dorsally) to reduce the carpal bones into their anatomical positions. Immediate open reduction is typically performed if closed reduction fails or if neurovascular compromise exists.

Question 2048

Topic: 7. Hand and Wrist

A 32-year-old construction worker presents with chronic radial-sided wrist pain, reduced grip strength, and limited range of motion following a fall 18 months prior. Radiographs show a scaphoid waist nonunion with dorsal intercalated segment instability (DISI) deformity and early degenerative changes in the radial scaphoid articulation. He previously underwent screw fixation with a non-vascularized bone graft, which failed to achieve union. What is the MOST appropriate surgical treatment for this symptomatic scaphoid nonunion with failed previous grafting and early arthrosis?

. Radial styloidectomy.
. Four-corner fusion.
. Proximal row carpectomy.
. Vascularized bone graft with revision internal fixation.
. Wrist denervation.

Correct Answer & Explanation

. Vascularized bone graft with revision internal fixation.

Explanation

For a symptomatic scaphoid nonunion with failed previous non-vascularized grafting, dorsal intercalated segment instability (DISI), and early degenerative changes, a vascularized bone graft with revision internal fixation is often the most appropriate surgical option. Vascularized grafts provide a robust biological environment for healing, especially in cases of recalcitrant nonunion or avascular segments, and aim to achieve union while preserving wrist motion. Radial styloidectomy is rarely definitive for nonunion. Four-corner fusion or proximal row carpectomy are salvage procedures typically reserved for more advanced degenerative changes (SLAC/SNAC wrist) where joint preservation is no longer feasible. Wrist denervation is a pain management strategy, not a reconstructive solution.

Question 2049

Topic: 7. Hand and Wrist

A 40-year-old manual laborer presents with chronic right wrist pain, particularly with grip and heavy lifting, for the past 2 years. He reports a remote history of a fall on an outstretched hand. Clinical examination reveals localized tenderness over the anatomical snuffbox and painful wrist extension. Radiographs are obtained:

The radiographs show a scaphoid nonunion with associated dorsal intercalated segmental instability (DISI) pattern. What is the MOST appropriate surgical management for this stage of wrist pathology?

. Percutaneous screw fixation of the scaphoid.
. Proximal row carpectomy (PRC).
. Scaphoid nonunion repair with bone graft and internal fixation.
. Four-corner arthrodesis.
. Wrist arthrodesis.

Correct Answer & Explanation

. Scaphoid nonunion repair with bone graft and internal fixation.

Explanation

The image provided shows a wrist X-ray, likely demonstrating carpal pathology. The patient has a chronic scaphoid nonunion with associated DISI. This represents a more advanced stage of scaphoid nonunion advanced collapse (SNAC) or scaphoid nonunion with carpal instability. DISI indicates significant collapse of the carpus with dorsal tilt of the lunate, a consequence of chronic scaphoid nonunion and altered carpal mechanics.At this stage, the primary goal is to address the nonunion and correct the carpal instability if possible, provided there is not severe widespread arthritic change. Percutaneous fixation is only for acute, undisplaced scaphoid fractures. Proximal row carpectomy (PRC) and four-corner arthrodesis are salvage procedures for wrists with established arthritis, which is not explicitly stated as widespread yet, but DISI pattern often implies impending or early arthritis at the radioscaphoid joint. Wrist arthrodesis is a more aggressive salvage for global wrist arthritis or instability.Repair of the scaphoid nonunion with bone grafting (vascularized or non-vascularized) and internal fixation is the gold standard to achieve union and prevent progression of carpal collapse. Success in achieving union can prevent or slow the progression of arthritis and improve wrist kinematics. Given the chronic nature and DISI, a thorough reconstruction of the scaphoid with bone grafting is required.Rationale for options:A. Percutaneous screw fixation is suitable for acute, undisplaced scaphoid fractures or select cases of stable nonunions without significant deformity, not for chronic nonunion with DISI.B. Proximal row carpectomy (PRC) is a salvage procedure for radioscaphoid arthritis with a healthy lunate facet of the capitate, not typically for nonunion without established advanced arthritis.C. Scaphoid nonunion repair with bone graft (e.g., iliac crest or vascularized graft) and internal fixation (e.g., screw or K-wires) is the most appropriate treatment to achieve union, correct the DISI deformity, and restore carpal kinematics in cases of chronic nonunion with instability but without severe pan-carpal arthritis. This is the correct answer.D. Four-corner arthrodesis (fusion of capitate, lunate, triquetrum, hamate, with scaphoid excision) is a salvage procedure performed for radioscaphoid arthritis or early midcarpal arthritis, typically when scaphoid nonunion has progressed to significant collapse with secondary arthritic changes. While DISI suggests progression, without explicit severe arthritis, scaphoid reconstruction is usually tried first.E. Wrist arthrodesis (fusion of radius, carpals, metacarpals) is a last-resort salvage procedure for severe, diffuse wrist arthritis, instability, or failed previous surgeries, resulting in loss of motion but pain relief.

Question 2050

Topic: 7. Hand and Wrist

A 68-year-old male with long-standing rheumatoid arthritis presents with progressive wrist pain, swelling, and instability. Clinical examination reveals significant ulnar deviation of the wrist, dorsal subluxation of the extensor carpi ulnaris (ECU) tendon, and progressive rupture of multiple extensor tendons, leading to inability to extend the fingers (Vaughn-Jackson syndrome). Radiographs confirm severe carpal destruction, proximal carpal migration, and significant arthritis of the distal radioulnar joint (DRUJ). What is the MOST appropriate surgical management for this complex wrist pathology?

. Dorsal wrist synovectomy and ECU stabilization.
. Total wrist arthroplasty (TWA).
. Darrach procedure (distal ulna excision).
. Sauve-Kapandji procedure (DRUJ arthrodesis with distal ulna pseudarthrosis).
. Wrist arthrodesis.

Correct Answer & Explanation

. Wrist arthrodesis.

Explanation

The patient presents with advanced rheumatoid arthritis affecting the wrist, characterized by severe carpal destruction, DRUJ arthritis, instability (ulnar deviation, ECU subluxation), and extensor tendon ruptures (Vaughn-Jackson syndrome). This represents a complex, multi-faceted problem.Simple synovectomy or isolated tendon repair is insufficient for this advanced stage. Total wrist arthroplasty (TWA) is an option for pain relief and motion preservation, but it may be contraindicated in cases of significant bone loss, active infection, or high-demand patients, and its longevity in severe RA can be limited. Darrach procedure (distal ulna excision) addresses DRUJ pain but doesn't stabilize the wrist or reconstruct tendons. Sauve-Kapandji addresses DRUJ issues but not the carpal destruction or tendon ruptures.Given the severe carpal destruction, progressive instability, and multiple tendon ruptures, wrist arthrodesis (fusion) is often the most reliable and durable surgical option to achieve pain relief, stability, and provide a stable platform for subsequent extensor tendon reconstruction. While it sacrifices motion, it provides a functional, pain-free wrist that can withstand loads and facilitate activities of daily living. Tendon reconstruction, often with transfers, is performed concurrently or in a staged fashion.Rationale for options:A. Dorsal wrist synovectomy and ECU stabilization are appropriate for early-stage RA with synovitis and tendon issues, but not for severe carpal destruction and multiple tendon ruptures.B. Total wrist arthroplasty (TWA) aims to preserve motion but may be associated with higher rates of loosening or failure in severe rheumatoid arthritis with significant bone loss and instability. It is generally considered for lower-demand patients or less severe destruction.C. Darrach procedure (distal ulna excision) addresses painful DRUJ arthritis but does not correct carpal instability, tendon ruptures, or generalized wrist arthritis.D. Sauve-Kapandji procedure involves DRUJ arthrodesis with a distal ulna pseudarthrosis. It addresses DRUJ issues, but like the Darrach, does not correct the overall carpal instability, tendon ruptures, or the severe carpal destruction mentioned.E. Wrist arthrodesis (fusion of the radius to the carpus and often to the third metacarpal) is the most definitive and durable solution for end-stage rheumatoid wrist with severe pain, deformity, instability, and tendon ruptures. It provides a stable, pain-free platform, allowing for improved grip and function after tendon reconstruction. This is the correct answer.

Question 2051

Topic: Nerve & Tendon

A 40-year-old cyclist presents with numbness and tingling confined entirely to the volar aspect of the ring and small fingers, with profound weakness of the intrinsic hand muscles. Sensation on the dorsal aspect of the ulnar hand is completely normal.

At which anatomical location is the ulnar nerve most likely compressed?

. Cubital tunnel
. Arcade of Struthers
. Guyon's canal (Zone 1)
. Guyon's canal (Zone 2)
. Guyon's canal (Zone 3)

Correct Answer & Explanation

. Guyon's canal (Zone 1)

Explanation

The patient has signs of both motor weakness (intrinsics) and sensory deficits (volar ring/small fingers), but crucially, the dorsal ulnar sensory nerve (DUSN) territory is spared. The DUSN branches off the ulnar nerve approximately 5-8 cm proximal to the wrist. Therefore, the compression must be distal to this branch. Guyon's canal Zone 1 contains both the deep motor branch and the superficial sensory branch of the ulnar nerve. Compression here explains both motor and volar sensory findings while sparing dorsal sensation. Cubital tunnel or Arcade of Struthers compression would typically involve the DUSN. Zone 2 is motor only, and Zone 3 is sensory only.

Question 2052

Topic: Hand Trauma & Infection
A 35-year-old male presents with a swollen, exquisitely tender index finger 3 days after sustaining a puncture wound. Suppurative flexor tenosynovitis is suspected. Which of the following is NOT a classic Kanavel sign?
. Fusiform swelling of the entire digit
. Pain with active extension only
. Tenderness along the course of the flexor tendon sheath
. Flexed resting posture of the digit

Correct Answer & Explanation

. Pain with active extension only

Explanation

The four classic Kanavel signs are: 1) fusiform swelling, 2) flexed resting posture, 3) tenderness along the flexor sheath, and 4) pain with PASSIVE extension. Pain with active extension is not a Kanavel sign.

Question 2053

Topic: 7. Hand and Wrist

A 22-year-old male falls on an outstretched hand and sustains a proximal pole scaphoid fracture. The risk of avascular necrosis is high due to the retrograde nature of the scaphoid's blood supply. Which artery provides the primary blood supply to the proximal pole of the scaphoid?

. Superficial palmar arch
. Dorsal carpal branch of the radial artery
. Volar carpal branch of the radial artery
. Ulnar artery

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery

Explanation

The primary blood supply to the scaphoid is from the dorsal carpal branch of the radial artery, which enters the scaphoid distally and flows retrograde to supply the proximal pole. Because of this retrograde flow, fractures at the waist or proximal pole easily disrupt the blood supply to the proximal fragment, leading to a high rate of avascular necrosis.

Question 2054

Topic: 7. Hand and Wrist

During primary repair of a Zone II flexor tendon laceration in the hand, preserving the integrity of the flexor tendon sheath and pulley system is imperative to ensure optimal finger kinematics. Biomechanically, which two pulleys are the most critical to preserve or reconstruct to prevent bowstringing of the flexor tendons?

. A1 and A3
. A2 and A4
. A3 and A5
. C1 and C3
. A1 and A5

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 pulley (located over the proximal aspect of the proximal phalanx) and the A4 pulley (located over the middle aspect of the middle phalanx) are the major annular pulleys. They are structurally the widest and strongest pulleys and are biomechanically the most critical for preventing bowstringing and maintaining the normal moment arm of the flexor tendons during digit flexion.

Question 2055

Topic: Wrist & Carpus

In the surgical treatment of complex intra-articular distal radius fractures, a volar marginal fragment involving the lunate facet (the 'lunate drop-out' or 'Melone' fragment) is notoriously difficult to capture with standard fixed-angle volar locking plates. Failure to secure this specific fragment most commonly results in which of the following complications?

. Dorsal subluxation of the entire carpus.
. Volar subluxation of the carpus.
. Avascular necrosis of the scaphoid.
. Rupture of the extensor pollicis longus (EPL) tendon.
. Proximal migration of the radius resulting in ulnar positive variance.

Correct Answer & Explanation

. Volar subluxation of the carpus.

Explanation

The volar lunate facet fragment provides critical bony support for the strong short radiolunate ligament. Because this ligament remains attached to the fragment, if the fragment is not anatomically secured (e.g., if a volar plate is placed too proximally to buttress it), the lunateโ€”and consequently the rest of the carpusโ€”will subluxate or dislocate volarly off the distal radius. This catastrophic failure is a well-known complication of inadequately fixing the volar lunate facet.

Question 2056

Topic: 7. Hand and Wrist
A patient with Scapholunate Advanced Collapse (SLAC) wrist presents for surgical intervention. Radiographs reveal advanced osteoarthritis at the radioscaphoid and capitolunate joints, but the radiolunate joint is completely spared. Which of the following procedures is most appropriate?
. Proximal row carpectomy (PRC)
. Four-corner arthrodesis with scaphoid excision
. Radioscapholunate (RSL) arthrodesis
. Total wrist arthroplasty
. Scaphotrapeziotrapezoid (STT) arthrodesis

Correct Answer & Explanation

. Four-corner arthrodesis with scaphoid excision

Explanation

This patient has Stage III SLAC wrist (capitolunate involvement). Proximal row carpectomy is contraindicated due to capitolunate arthritis (the capitate would articulate with the lunate fossa). The procedure of choice is a four-corner fusion (capitate, hamate, lunate, triquetrum) with scaphoid excision.

Question 2057

Topic: 7. Hand and Wrist
A 25-year-old male sustains a laceration to the volar aspect of his index finger at the level of the middle phalanx, just proximal to the DIP joint. Examination reveals an inability to flex the DIP joint, but PIP flexion against resistance is intact. In which flexor tendon zone did the injury occur, and what is the optimal surgical timing?
. Zone I; immediate repair in the emergency department.
. Zone I; primary repair within 1 to 2 weeks.
. Zone II; primary repair within 1 to 2 weeks.
. Zone II; delayed primary repair at 4 weeks.
. Zone III; primary repair within 1 to 2 weeks.

Correct Answer & Explanation

. Zone I; primary repair within 1 to 2 weeks.

Explanation

The injury is located at the middle phalanx, distal to the FDS insertion, placing it in Zone I (which contains only the FDP tendon). A purely FDP laceration allows intact PIP flexion. The standard of care is a primary repair in the operating room within 7 to 14 days to prevent tendon retraction and optimize outcomes.

Question 2058

Topic: 7. Hand and Wrist



A 26-year-old male presents with a proximal pole scaphoid fracture. The vascular supply to the scaphoid makes this region susceptible to avascular necrosis. Which vessel provides the primary blood supply to the proximal pole of the scaphoid?

. Volar carpal branch of the radial artery.
. Dorsal carpal branch of the radial artery.
. Deep palmar arch.
. Ulnar artery via the superficial palmar arch.
. Anterior interosseous artery.

Correct Answer & Explanation

. Dorsal carpal branch of the radial artery.

Explanation

The major blood supply to the scaphoid (providing 70-80% of its perfusion) comes from the dorsal carpal branch of the radial artery, which enters the scaphoid at the dorsal ridge (distal half) and flows in a retrograde fashion to supply the proximal pole. This retrograde blood flow is the primary reason why proximal pole scaphoid fractures carry a high risk for avascular necrosis and nonunion.

Question 2059

Topic: 7. Hand and Wrist

During a flexor tendon repair in Zone II of the hand, maintaining the integrity of the flexor tendon sheath and pulley system is crucial. Which two pulleys are considered the most critical to preserve in order to prevent bowstringing of the flexor tendons?

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

Correct Answer & Explanation

. A2 and A4

Explanation

The A2 (proximal phalanx) and A4 (middle phalanx) pulleys are the most biomechanically critical components of the flexor sheath. Loss of these pulleys leads to significant bowstringing and loss of active finger flexion.

Question 2060

Topic: 7. Hand and Wrist
A 45-year-old manual laborer presents with chronic radial-sided wrist pain. Radiographs reveal a scaphoid nonunion with radioscaphoid arthritis and capitolunate arthritis, but the radiolunate joint is preserved. This corresponds to a Stage III SNAC wrist. What is the most appropriate surgical intervention?
. Proximal row carpectomy
. Four-corner arthrodesis with scaphoid excision
. Total wrist arthrodesis
. Scaphoid open reduction and internal fixation with vascularized bone grafting
. Radial styloidectomy

Correct Answer & Explanation

. Four-corner arthrodesis with scaphoid excision

Explanation

Stage III SNAC involves radioscaphoid and midcarpal (capitolunate) arthritis with a preserved radiolunate joint. Proximal row carpectomy is contraindicated because the capitate head is arthritic; therefore, a four-corner fusion with scaphoid excision is the preferred salvage procedure.

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