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7. Hand and Wrist MCQs

Practice Set 184 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 3661

Topic: Wrist & Carpus

What is the primary goal of the 'sugar tong' splint in the initial management of a significantly displaced distal radius fracture?

. To allow for early range of motion
. To provide rigid internal fixation
. To provide rotational control and prevent forearm supination/pronation
. To facilitate weight-bearing on the wrist
. To minimize swelling through compression

Correct Answer & Explanation

. To provide rotational control and prevent forearm supination/pronation

Explanation

A sugar tong splint provides excellent immobilization and, critically, rotational control of the forearm. By extending above the elbow, it prevents supination and pronation, which are movements that can disrupt the reduction of a distal radius fracture, especially those with significant displacement or DRUJ involvement. It is a temporary measure, not a definitive fixation, and doesn't allow early motion or facilitate weight-bearing.

Question 3662

Topic: 7. Hand and Wrist

Which of the following ligaments is considered the primary extrinsic carpal stabilizer on the volar side of the wrist?

. Dorsal radiocarpal ligament
. Scapholunate ligament
. Lunotriquetral ligament
. Radioscaphocapitate ligament
. Ulnar collateral ligament

Correct Answer & Explanation

. Radioscaphocapitate ligament

Explanation

The Radioscaphocapitate (RSC) ligament is a major extrinsic volar ligament that originates from the radial styloid and inserts onto the scaphoid and capitate. It is a key stabilizer of the midcarpal joint and prevents excessive carpal flexion. The dorsal radiocarpal ligament is on the dorsal side. Scapholunate and lunotriquetral are intrinsic intercarpal ligaments. Ulnar collateral is on the ulnar side.

Question 3663

Topic: Nerve & Tendon

Which of the following is the MOST common nerve injury associated with elbow dislocations?

. Radial nerve.
. Median nerve.
. Ulnar nerve.
. Musculocutaneous nerve.
. Anterior interosseous nerve.

Correct Answer & Explanation

. Ulnar nerve.

Explanation

The ulnar nerve is the most commonly injured nerve in association with elbow dislocations, occurring in approximately 5-15% of cases. It is vulnerable as it crosses the elbow in the cubital tunnel posterior to the medial epicondyle. While radial and median nerves can also be injured, they are less common. The musculocutaneous and anterior interosseous nerves are even rarer in this context.

Question 3664

Topic: 7. Hand and Wrist

A patient with a radial head fracture-dislocation (Essex-Lopresti injury) presents with persistent wrist pain and instability. What is the underlying mechanism responsible for the wrist symptoms?

. Direct trauma to the wrist during the injury.
. Disruption of the distal radioulnar joint (DRUJ) leading to proximal migration of the radius.
. Ulnar nerve entrapment at the elbow affecting wrist flexors.
. Concomitant scaphoid fracture.
. Isolated injury to the triangular fibrocartilage complex (TFCC).

Correct Answer & Explanation

. Disruption of the distal radioulnar joint (DRUJ) leading to proximal migration of the radius.

Explanation

An Essex-Lopresti injury involves a radial head fracture, disruption of the interosseous membrane (IOM), and disruption of the distal radioulnar joint (DRUJ), leading to proximal migration of the radius. This proximal migration is the underlying mechanism responsible for the persistent wrist pain, instability, and potential impaction syndrome. It's not just a direct wrist trauma (Option A) or isolated TFCC injury (Option E), but a systemic injury to the forearm's longitudinal stability. Ulnar nerve entrapment (Option C) or scaphoid fracture (Option D) are unrelated or less common associated injuries.

Question 3665

Topic: Wrist & Carpus

What is the primary role of the interosseous membrane (IOM) in forearm stability?

. To prevent valgus instability of the elbow
. To resist pronation of the forearm
. To transmit axial loads from the radius to the ulna
. To provide attachment for the biceps tendon
. To stabilize the distal radio-ulnar joint (DRUJ) directly

Correct Answer & Explanation

. To transmit axial loads from the radius to the ulna

Explanation

The interosseous membrane (IOM) is crucial for longitudinal forearm stability, particularly in transmitting axial loads from the radius to the ulna. It acts as a primary load-bearing structure between the two bones, especially during activities involving compression through the hand. It doesn't primarily prevent valgus instability (that's MCL's role), resist pronation, or directly stabilize the DRUJ (though its disruption leads to DRUJ issues), nor is it for biceps attachment.

Question 3666

Topic: Nerve & Tendon

Which nerve is at highest risk during a medial approach to the elbow, which might be considered if other structures need repair alongside a radial head fracture (e.g., MCL)?

. Radial nerve
. Median nerve
. Ulnar nerve
. Musculocutaneous nerve
. Anterior interosseous nerve

Correct Answer & Explanation

. Ulnar nerve

Explanation

The ulnar nerve is the nerve at highest risk during a medial approach to the elbow. It runs in the cubital tunnel posterior to the medial epicondyle and is superficial in this region. Care must be taken to identify and protect it. Radial and median nerves are located more anterior and lateral to the medial epicondyle respectively, and are not the primary concern with a medial approach.

Question 3667

Topic: Nerve & Tendon

A patient undergoing ORIF for a radial head fracture complains of numbness and tingling in the small and ring fingers post-operatively. Which nerve is most likely affected?

. Radial nerve
. Median nerve
. Ulnar nerve
. Musculocutaneous nerve
. Lateral cutaneous nerve of the forearm

Correct Answer & Explanation

. Ulnar nerve

Explanation

Numbness and tingling in the small and ring fingers are characteristic symptoms of ulnar nerve compression or injury. The ulnar nerve runs posteriorly to the medial epicondyle (cubital tunnel) and can be affected by direct trauma, swelling, or surgical manipulation during elbow procedures, including those for radial head fractures, particularly if a medial approach is used or the elbow is acutely swollen/positioned. Radial and median nerves would present with different sensory deficits.

Question 3668

Topic: Wrist & Carpus

Which of the following describes the function of the oblique cord?

. Primary stabilizer of the distal radioulnar joint
. Reinforces the anterior capsule of the elbow
. Secondary stabilizer of the forearm resisting proximal migration of the radius
. Maintains the position of the radial head in the lesser sigmoid notch
. Prevents valgus stress at the elbow

Correct Answer & Explanation

. Secondary stabilizer of the forearm resisting proximal migration of the radius

Explanation

The oblique cord is a fibrous band extending from the ulna to the radius, just distal to the radial tuberosity. It is considered a secondary stabilizer of the forearm, providing some resistance to proximal migration of the radius. While not as strong as the interosseous membrane, it contributes to longitudinal stability. It does not primarily stabilize the DRUJ (TFCC does that), reinforce the anterior capsule, maintain radial head position (annular ligament), or prevent valgus stress (MCL/radial head).

Question 3669

Topic: 7. Hand and Wrist

A 40-year-old patient with a Mason-Johnston Type II radial head fracture undergoes ORIF. Post-operatively, they develop chronic elbow pain, stiffness, and crepitus that is unresponsive to therapy. Radiographs show no hardware impingement or loosening. What long-term complication might be suspected?

. Neuroma of the radial nerve
. Deep vein thrombosis
. Post-traumatic osteoarthritis
. Carpal tunnel syndrome
. Reflex sympathetic dystrophy (CRPS)

Correct Answer & Explanation

. Post-traumatic osteoarthritis

Explanation

Chronic pain, stiffness, and crepitus following an intra-articular fracture, even after successful ORIF, often indicate the development of post-traumatic osteoarthritis. Despite anatomic reduction, the initial cartilage injury and altered biomechanics can lead to progressive articular degeneration. While CRPS is a possibility for chronic pain, osteoarthritis is a common outcome from articular fractures. Neuroma and carpal tunnel are nerve issues, and DVT is a vascular complication.

Question 3670

Topic: Nerve & Tendon

What is the primary role of the A4 pulley in the context of an FDP avulsion injury?

. It is the main pulley restricting FDP tendon retraction in Type I injuries.
. It provides the primary blood supply to the FDP tendon at the DIP level.
. It helps maintain the mechanical advantage of the FDP tendon, particularly during DIP flexion.
. Its integrity is crucial for preventing a boutonniere deformity.
. It prevents subluxation of the FDP tendon at the MCP joint.

Correct Answer & Explanation

. It helps maintain the mechanical advantage of the FDP tendon, particularly during DIP flexion.

Explanation

The A4 pulley, located over the middle of the distal phalanx, is crucial for maintaining the mechanical advantage of the FDP tendon for DIP joint flexion. Its integrity is important for effective FDP function. The A2 pulley is also very important for FDP mechanics. The A4 pulley does not primarily restrict retraction in Type I injuries (where the tendon often retracts to the palm). The vincula provide blood supply. It is not directly related to preventing a boutonniere deformity (which involves the central slip). It does not prevent FDP subluxation at the MCP joint (which involves the A1 pulley and sagitall bands).

Question 3671

Topic: Nerve & Tendon

A 50-year-old carpenter sustained a Type I Jersey finger 3 days ago. During surgical exploration, the FDP tendon is found to be significantly retracted into the palm. What method is typically employed to retrieve the retracted tendon for repair?

. Use of a nerve hook through the flexor sheath.
. Extension of the incision proximally into the palm.
. Milking the forearm muscles to advance the tendon distally.
. Insertion of a specialized tendon retriever through the flexor sheath.
. Both B and D are common and effective techniques.

Correct Answer & Explanation

. Both B and D are common and effective techniques.

Explanation

Retrieving a significantly retracted FDP tendon (common in Type I injuries) often requires extending the Brunner's incision proximally into the palm to directly visualize and grasp the tendon. Additionally, specialized tendon retrievers can be used to pass through the flexor sheath from the distal incision to ensnare and pull the retracted tendon distally. Using a nerve hook alone may be insufficient for substantial retraction, and 'milking' muscles is not a precise surgical technique for tendon retrieval. Therefore, both extending the incision and using a tendon retriever are common and effective.

Question 3672

Topic: Nerve & Tendon

Which factor is most likely to lead to a poor outcome following primary FDP repair for a Jersey finger?

. Repair within 7 days of injury.
. Adherence to an early active motion rehabilitation protocol.
. Smoking history of the patient.
. Use of a two-strand core suture technique.
. Associated A2 pulley rupture.

Correct Answer & Explanation

. Smoking history of the patient.

Explanation

Smoking significantly impairs wound healing and tendon repair due to its vasoconstrictive effects and negative impact on collagen synthesis, making it a strong predictor of poor outcomes and complications like re-rupture and stiffness. Repair within 7 days is associated with better outcomes, especially for Type I. Early active motion protocols are generally favored for improving outcomes. A two-strand core suture is typically considered a less strong repair compared to 4-strand or 6-strand, but its use alone is not the strongest predictor of poor outcome compared to smoking. An associated A2 pulley rupture would be addressed during surgery and may complicate rehab but not necessarily lead to a 'poor outcome' more than smoking.

Question 3673

Topic: 7. Hand and Wrist

A 30-year-old recreational athlete presents with a Jersey finger of the ring finger. Initial X-rays show no bony avulsion. An MRI is ordered and confirms a complete FDP avulsion, with the tendon retracted to the level of the proximal phalanx, indicating a Type II Leddy and Packer injury. What is the rationale for the slightly less urgent surgical timing compared to a Type I injury?

. The tendon has a better chance of spontaneous reattachment.
. The A2 pulley prevents further retraction, maintaining some blood supply.
. The vincula tendinum are more likely to remain intact, preserving vascularity.
. The associated nerve injury is less severe, allowing for delay.
. There is a lower risk of post-operative stiffness with delayed repair.

Correct Answer & Explanation

. The vincula tendinum are more likely to remain intact, preserving vascularity.

Explanation

In a Type II Jersey finger, the FDP tendon retracts to the level of the PIP joint or proximal phalanx, but often, one or more vincula tendinum (specifically the vinculum breve to the FDP or vinculum longum to the FDS) remain intact, preserving some blood supply to the tendon. This better vascularity compared to a Type I injury (where the tendon often retracts into the palm and loses its vincula) allows for a slightly less urgent surgical window (up to 2-3 weeks). The A2 pulley does not typically prevent retraction to this extent in a Type II injury, nor does it primarily supply blood. Spontaneous reattachment is rare, and nerve injury is not the distinguishing factor here.

Question 3674

Topic: Nerve & Tendon

Following FDP repair, which of the following is a potential complication specifically associated with avulsion fractures where a large bone fragment is reattached?

. Lumbrical plus phenomenon.
. Quadriga effect.
. Non-union of the bony fragment.
. Swan neck deformity.
. Boutonniere deformity.

Correct Answer & Explanation

. Non-union of the bony fragment.

Explanation

When a bony avulsion fragment is reattached, particularly if it's large, a potential complication is non-union or malunion of the bony fragment. This can lead to persistent pain, tenderness, or mechanical issues. Lumbrical plus and quadriga effect are related to tendon shortening/tensioning. Swan neck and boutonniere deformities are typically associated with extensor mechanism imbalances or other conditions, not directly with bony fragment reattachment from a Jersey finger, although stiffness can contribute to such deformities over time. Therefore, non-union of the bony fragment is the most direct and specific complication related to reattaching a bone fragment.

Question 3675

Topic: 7. Hand and Wrist

What is the typical management strategy for a Leddy and Packer Type IV Jersey finger injury?

. Primary repair of the FDP tendon to the remaining distal phalanx, excising the bony fragment.
. Reattachment of the FDP tendon to the avulsed bony fragment, followed by reattachment of the fragment to the distal phalanx.
. FDP advancement, if the gap is less than 1 cm, regardless of bony fragment.
. Staged tendon reconstruction, if presenting acutely.
. Non-operative management with extended immobilization for 6-8 weeks.

Correct Answer & Explanation

. Reattachment of the FDP tendon to the avulsed bony fragment, followed by reattachment of the fragment to the distal phalanx.

Explanation

A Leddy and Packer Type IV injury involves an avulsion of a bony fragment from the distal phalanx, but crucially, the FDP tendon has avulsed from this bony fragment and retracted further proximally. The management typically involves reattaching the FDP tendon back to the avulsed bony fragment, and then reattaching the bony fragment to the distal phalanx. This dual repair ensures both tendon and bone healing. Excising the fragment would sacrifice potential bone-to-bone healing and reduce the surface for tendon reattachment. FDP advancement is for tendon-only avulsions with a short gap. Staged reconstruction is for chronic cases or large gaps. Non-operative management is not indicated for this complete rupture.

Question 3676

Topic: 7. Hand and Wrist
Which of the following is a contraindication to primary flexor digitorum profundus (FDP) repair in a Jersey finger injury?
. Patient age over 60 years.
. Involvement of the small finger.
. Presence of an associated distal phalanx fracture.
. Significant tendon loss (e.g., >1 cm) or severe tendon degeneration making direct repair impossible.
. Pre-existing mild osteoarthritis in the DIP joint.

Correct Answer & Explanation

. Significant tendon loss (e.g., >1 cm) or severe tendon degeneration making direct repair impossible.

Explanation

Significant tendon loss or severe tendon degeneration that makes a direct, tension-free repair impossible is a contraindication to primary FDP repair. In such cases, alternative strategies like FDP advancement (if the gap is small) or staged tendon reconstruction are considered. Patient age, involvement of a specific finger (small finger often has poorer outcomes but is still repaired), an associated distal phalanx fracture (often part of Type III, IV, V injuries and addressed concurrently), and mild pre-existing osteoarthritis are generally not absolute contraindications, though they may influence prognosis or rehabilitation.

Question 3677

Topic: 7. Hand and Wrist
Which FDP injury is most likely to be successfully managed with FDP advancement alone, without the need for a tendon graft?
. A chronic Type I injury with significant tendon retraction into the forearm.
. A Type IV injury where the tendon has avulsed from a large bone fragment.
. An acute Type I injury with minimal tendon retraction (<1 cm) and good tissue quality.
. A Type III injury with a large intra-articular fragment.
. Any FDP rupture in a patient over 70 years old.

Correct Answer & Explanation

. An acute Type I injury with minimal tendon retraction (<1 cm) and good tissue quality.

Explanation

FDP advancement is a viable option for acute FDP ruptures (typically Type I) where there is minimal tendon retraction (generally less than 1 cm) and the remaining tendon quality is good. It involves shortening the tendon slightly to reattach it to the distal phalanx. For chronic injuries with significant retraction, Type IV injuries, or large gaps, advancement alone is usually insufficient due to excessive tension. Type III involves bony reattachment. Patient age itself doesn't determine feasibility of advancement, but older tendons may have poorer quality. Advancement for gaps over 1 cm often leads to excessive tension, a quadriga effect, or re-rupture.

Question 3678

Topic: Nerve & Tendon

A patient presents with a chronic FDP rupture of the ring finger (6 months post-injury). On examination, he has a noticeable hyperextension of the PIP joint and flexion of the MCP joint of the affected digit when attempting to make a fist. This clinical presentation is consistent with:

. A quadriga effect.
. A boutonniere deformity.
. A swan neck deformity.
. A lumbrical plus phenomenon.
. Central slip rupture.

Correct Answer & Explanation

. A lumbrical plus phenomenon.

Explanation

This describes the lumbrical plus phenomenon. In a chronic FDP rupture, the FDP tendon is slack or absent. When the patient attempts to flex the finger, the lumbrical muscle is put under tension, and its pull on the lateral bands results in paradoxical DIP extension and PIP hyperextension. The MCP joint may flex as the lumbrical also flexes the MCP. Quadriga effect limits flexion of adjacent fingers. Boutonniere is PIP flexion and DIP hyperextension. Swan neck is PIP hyperextension and DIP flexion. Central slip rupture causes boutonniere. The specific pattern of attempted flexion leading to PIP hyperextension and DIP extension is key for lumbrical plus.

Question 3679

Topic: 7. Hand and Wrist
In the Leddy and Packer classification, what distinguishes a Type V injury from a Type III or IV injury?
. Type V involves retraction to the palm, while Type III and IV remain at the A4 pulley.
. Type V involves a complete tendon avulsion without any bony involvement.
. Type V specifically denotes an intra-articular fracture of the distal phalanx with FDP avulsion.
. Type V indicates a chronic injury greater than 6 weeks, whereas Type III and IV are acute.
. Type V is exclusively associated with concomitant neurovascular injury.

Correct Answer & Explanation

. Type V specifically denotes an intra-articular fracture of the distal phalanx with FDP avulsion.

Explanation

The Leddy and Packer classification was initially I, II, III. Type IV was later added for bony avulsion where the tendon also avulses from the fragment. Type V is a more recent addition and specifically describes an intra-articular fracture of the distal phalanx that is associated with an FDP tendon avulsion. This implies articular involvement that needs specific attention beyond just reattaching a bone fragment. The other options describe features of other types or are incorrect.

Question 3680

Topic: 7. Hand and Wrist

When assessing for a Jersey finger, what would be the expected finding on a 'modified tabletop test' for a patient with a complete FDP rupture of the ring finger?

. The affected ring finger DIP joint would be in full flexion.
. The affected ring finger DIP joint would be hyperextended.
. The affected ring finger DIP joint would remain extended or slightly flexed, disrupting the normal cascade.
. All fingers would demonstrate a uniform inability to flex the DIP joint.
. The ring finger PIP joint would be unable to flex.

Correct Answer & Explanation

. The affected ring finger DIP joint would remain extended or slightly flexed, disrupting the normal cascade.

Explanation

The modified tabletop test (or cascade test) assesses the resting posture of the fingers. Normally, when the hand is at rest, there is a progressive cascade of flexion from the index to the small finger. With a complete FDP rupture, the affected finger's DIP joint will lose its resting flexion tone and will remain extended or only slightly flexed, disrupting this normal cascade. It would not be in full flexion or hyperextended, nor would all fingers be affected. The PIP joint flexion is controlled by the FDS, so it would typically be normal in an isolated FDP rupture.

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