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 941
Topic: 7. Hand and Wrist
A 24-year-old male falls onto an outstretched hand and sustains a displaced fracture of the proximal pole of the scaphoid. The high risk of avascular necrosis in this region is primarily due to the retrograde blood supply from which vessel?
Correct Answer & Explanation
. Dorsal carpal branch of the radial artery
Explanation
The scaphoid receives its primary blood supply from the dorsal carpal branch of the radial artery, which enters distally and flows in a retrograde fashion. Consequently, proximal pole fractures are at a very high risk for avascular necrosis.
Question 942
Topic: 7. Hand and Wrist
The primary muscle involved in lateral epicondylitis originates at the lateral epicondyle. Where is its anatomic distal insertion?
Correct Answer & Explanation
. Base of the third metacarpal
Explanation
The extensor carpi radialis brevis (ECRB) is the primary structure involved in lateral epicondylitis. It inserts onto the dorsal base of the third metacarpal.
Question 943
Topic: Nerve & Tendon
A 40-year-old mechanic presents with lateral elbow pain. Pain is reproduced with resisted active supination of the forearm with the elbow extended. Where is the most likely site of compression causing this patient's symptoms?
Correct Answer & Explanation
. Arcade of Frohse
Explanation
Resisted active supination reproducing lateral forearm pain suggests Radial Tunnel Syndrome, a major differential diagnosis for lateral epicondylitis. The posterior interosseous nerve is most commonly compressed at the proximal edge of the supinator, known as the Arcade of Frohse.
Question 944
Topic: Nerve & Tendon
Which physical examination finding most reliably differentiates Radial Tunnel Syndrome from Lateral Epicondylitis?
Correct Answer & Explanation
. Maximal tenderness 4 to 5 cm distal to the lateral epicondyle
Explanation
Radial Tunnel Syndrome typically presents with maximal point tenderness in the mobile wad 4 to 5 cm distal to the lateral epicondyle. In contrast, lateral epicondylitis presents with maximal tenderness directly over or just slightly distal to the epicondyle.
Question 945
Topic: Nerve & Tendon
A 42-year-old carpenter complains of aching pain in the lateral proximal forearm. Tenderness is maximal 4 cm distal to the lateral epicondyle in the mobile wad. Pain is exacerbated by resisted forearm supination with the elbow fully extended. Which nerve is most likely compressed?
Correct Answer & Explanation
. Posterior interosseous nerve (PIN)
Explanation
This presentation describes radial tunnel syndrome, a compression neuropathy of the PIN. It is a critical differential for tennis elbow, characterized by tenderness more distal than the epicondyle and pain provoked by resisted supination.
Question 946
Topic: 7. Hand and Wrist
Lateral epicondylitis has been noted in the literature to frequently co-occur with which of the following upper extremity conditions?
Correct Answer & Explanation
. Rotator cuff tendinopathy
Explanation
Lateral epicondylitis is considered part of a systemic tendinopathic profile. It is commonly associated with other degenerative tendon conditions, particularly rotator cuff tendinopathy, suggesting a potential intrinsic predisposition to tendinosis.
Question 947
Topic: Nerve & Tendon
A 58-year-old female presents with a complex, comminuted intra-articular distal humerus fracture (AO/OTA Type C3) after a fall from standing height. Pre-operative CT scans confirm significant articular involvement and disruption of both medial and lateral columns. During surgical planning for a posterior approach, the surgeon decides to perform an olecranon osteotomy. Which of the following statements regarding the ulnar nerve and its management during this procedure is MOST accurate?
Correct Answer & Explanation
. Prophylactic anterior transposition of the ulnar nerve is widely recommended to reduce post-operative neuropathy rates, even in asymptomatic patients.
Explanation
Correct Answer: CThe case explicitly states, 'The ulnar nerve is identified proximal to the cubital tunnel, typically lying anterior to the medial head of the triceps. Trace the nerve distally through the cubital tunnel (between the medial epicondyle and olecranon). Perform an extensive neurolysis of the ulnar nerve... While not always strictly necessary in every case, anterior transposition of the ulnar nerve is generally recommended during open reduction internal fixation (ORIF) of DHFs via a posterior approach. This protects the nerve from direct injury during drilling, plating, and screw insertion, and prevents post-operative compression from hardware or scar tissue.' The 'Summary of Key Literature / Guidelines' section further reinforces this: 'Prophylactic anterior transposition of the ulnar nerve during posterior approaches for DHF ORIF is widely recommended. Studies have shown a significant reduction in post-operative ulnar neuropathy rates with routine transposition compared to in situ decompression or no specific management.'Option A is incorrectbecause prophylactic transposition is recommended regardless of pre-operative symptoms due to the high risk of iatrogenic injury or post-operative compression.Option B is incorrectbecause the ulnar nerve is located posteriorly to the medial epicondyle, within the cubital tunnel, not anteriorly, and the brachialis muscle is anterior to the humerus, not directly protecting the ulnar nerve in the cubital tunnel.Option D is incorrectbecause while the ulnar nerve can be at risk from hardware, its primary risk during a posterior approach is from direct injury during dissection, retraction, or compression from hardware/scar tissue in the cubital tunnel, not specifically from lateral column screw placement. Lateral column screws are more likely to endanger the radial nerve if excessively long or misplaced.Option E is incorrectbecause the cubital tunnel is formed by the medial epicondyle and the olecranon, with the arcuate ligament forming the roof, not the radial head.
Question 948
Topic: Nerve & Tendon
A 35-year-old male sustains a distal humerus fracture. During the physical examination, the orthopedic resident assesses the stability of the elbow joint. Which of the following combinations of structures provides the primary static stability to the elbow joint?
Correct Answer & Explanation
. Osseous congruence (trochlear notch with trochlea) and collateral ligaments (MCL, LCL complex).
Explanation
Correct Answer: CThe 'Surgical Anatomy & Biomechanics' section, under 'Biomechanics' and 'Elbow Joint Stability', states: 'The elbow derives its stability from a combination of osseous congruence (trochlear notch of ulna with trochlea of humerus), static ligamentous restraints (MCL, LCL complex), and dynamic muscular contributions.' Osseous congruence and static ligamentous restraints are the primary static stabilizers.Option A is incorrectbecause the triceps and anconeus are dynamic muscular stabilizers, not primary static stabilizers.Option B is incorrectbecause the radial and ulnar nerves are neurovascular structures, not stabilizers of the joint.Option D is incorrectbecause the brachialis muscle and biceps tendon are dynamic muscular stabilizers, not primary static stabilizers.Option E is incorrectbecause the median nerve and brachial artery are neurovascular structures, not stabilizers of the joint.
Question 949
Topic: Wrist & Carpus
A 25-year-old male sustains a Galeazzi fracture-dislocation. After anatomic rigid fixation of the radius, the distal radioulnar joint (DRUJ) remains unstable in neutral but reduces and is stable in full supination. What is the most appropriate next step in management?
Correct Answer & Explanation
. Immobilization of the forearm in a long-arm cast or splint in supination for 4-6 weeks
Explanation
If the DRUJ is unstable in neutral but stable in supination following anatomic radius fixation, nonoperative management with supination splinting or casting for 4-6 weeks is indicated. Pinning or TFCC repair is generally reserved for cases where the DRUJ remains unstable even in full supination.
Question 950
Topic: 7. Hand and Wrist
A 40-year-old undergoes ORIF of a radial shaft fracture using the dorsal (Thompson) approach. Postoperatively, the patient cannot extend the fingers at the metacarpophalangeal (MCP) joints but has intact wrist extension. Which nerve was injured?
Correct Answer & Explanation
. Posterior interosseous nerve (PIN)
Explanation
The PIN is at high risk during the Thompson approach, located between the ECRB and EDC. Injury causes loss of finger and thumb extension at the MCP joints, while wrist extension is preserved due to intact innervation of the ECRL.
Question 951
Topic: Wrist & Carpus
A 29-year-old man sustains a Galeazzi fracture-dislocation. Following rigid plate fixation of the radial diaphysis, the distal radioulnar joint (DRUJ) remains persistently subluxated despite supination. Which of the following structures is most commonly interposed, blocking anatomic reduction of the DRUJ?
Correct Answer & Explanation
. Extensor Carpi Ulnaris (ECU) tendon
Explanation
In a Galeazzi fracture, if the DRUJ is irreducible after anatomic fixation of the radius, soft tissue interposition is likely. The Extensor Carpi Ulnaris (ECU) tendon is the most commonly interposed structure.
Question 952
Topic: Nerve & Tendon
During open reduction and internal fixation of a bicolumnar distal humerus fracture, the surgeon is exposing the ulnar nerve. Based on recent high-level evidence regarding ulnar nerve management in distal humerus ORIF, which of the following is the most appropriate strategy if the nerve does not subluxate and hardware does not impinge upon it?
Correct Answer & Explanation
. In situ decompression and retention in the cubital tunnel
Explanation
Recent studies suggest that routine anterior transposition of the ulnar nerve during distal humerus ORIF is associated with higher rates of ulnar neuritis. In situ decompression is preferred unless hardware impinges on the nerve or it is unstable.
Question 953
Topic: 7. Hand and Wrist
A surgeon utilizes the volar (Henry) approach to fix a distal radius diaphyseal fracture. In the distal third of the forearm, the surgical interval is developed between which two structures?
Correct Answer & Explanation
. Brachioradialis and Flexor Carpi Radialis
Explanation
The distal interval for the volar (Henry) approach to the radius lies between the Brachioradialis (innervated by the radial nerve) and the Flexor Carpi Radialis (innervated by the median nerve).
Question 954
Topic: 7. Hand and Wrist
A 33-year-old male presents with an anterior Monteggia fracture-dislocation (Bado Type I). On clinical examination, he is unable to extend his thumb or digits at the metacarpophalangeal joints, but wrist extension is preserved with radial deviation. Assuming closed reduction of the radial head and ORIF of the ulna are successful, what is the most appropriate management of the neurologic deficit?
Correct Answer & Explanation
. Observation for 3 to 6 months before considering exploration
Explanation
The patient has a posterior interosseous nerve (PIN) palsy, the most common nerve injury associated with an anterior Monteggia fracture. These are typically neurapraxias that resolve spontaneously, so observation for 3 to 6 months is the standard of care.
Question 955
Topic: 7. Hand and Wrist
A 45-year-old male falls onto an outstretched hand, sustaining a radial head fracture, distal radioulnar joint (DRUJ) disruption, and interosseous membrane tear. Initial management must explicitly avoid which of the following procedures to prevent chronic wrist pain and progressive deformity?
Correct Answer & Explanation
. Radial head excision without replacement
Explanation
This clinical presentation describes an Essex-Lopresti injury. Radial head excision without replacement removes the secondary stabilizer to longitudinal forearm translation, leading to proximal migration of the radius, positive ulnar variance, and chronic DRUJ pain.
Question 956
Topic: Wrist & Carpus
A 28-year-old male undergoes ORIF for a highly comminuted both-bone forearm fracture. Six months postoperatively, radiographs demonstrate bridging callus and union, but he has a 40-degree deficit in supination. The radial bow was reconstructed with 10% less magnitude than the contralateral side. What is the most likely cause of his restricted supination?
Correct Answer & Explanation
. Loss of radial bow magnitude
Explanation
Restoration of the radial bow is critical for maintaining normal forearm rotation. A loss of the magnitude of the radial bow (even minor alterations) or shifting of the apex of the bow directly correlates with a mechanical loss of forearm rotation, particularly pronation and supination.
Question 957
Topic: Wrist & Carpus
A 45-year-old mechanic sustains a Galeazzi fracture-dislocation. Following rigid plate fixation of the radial shaft, the distal radioulnar joint (DRUJ) is noted to be grossly unstable in supination. What is the recommended acute management for the DRUJ?
Correct Answer & Explanation
. Pin the DRUJ in supination or immobilize in a long-arm cast in supination
Explanation
In a Galeazzi fracture, if the DRUJ remains unstable after anatomic radius fixation, the forearm should be assessed in supination. If stable in supination, immobilization in a long-arm cast in supination is indicated; if still unstable, percutaneous pinning of the DRUJ in supination is recommended.
Question 958
Topic: 7. Hand and Wrist
A 62-year-old female undergoes open reduction and internal fixation of a distal radius fracture with a volar locking plate. Six months postoperatively, she develops progressive pain and weakness with thumb extension, eventually leading to an Extensor Pollicis Longus (EPL) rupture. What is the most likely cause of this complication?
Correct Answer & Explanation
. Penetration of the dorsal cortex by excessively long screws, irritating the EPL tendon.
Explanation
Correct Answer: DPenetration of the dorsal cortex by excessively long screws is a well-known and critical complication of volar distal radius plating. The Extensor Pollicis Longus (EPL) tendon, along with other extensor tendons, lies in close proximity to the dorsal cortex. Even slight screw prominence can cause chronic irritation, attrition, and eventual rupture of these tendons, particularly the EPL due to its course around Lister's tubercle. Careful measurement of screw length and intraoperative fluoroscopic verification in multiple planes are essential to prevent this.Option A is incorrect:While over-tightening can damage plate threads, it's not a direct cause of EPL rupture.Option B is incorrect:Inadequate screws would lead to construct instability and fracture displacement, not typically isolated EPL rupture.Option C is incorrect:Improper plate contouring can cause flexor tendon irritation if the plate is too prominent volarly, but EPL rupture is a dorsal complication.Option E is incorrect:Median nerve injury is a risk during the volar approach, but it would present with sensory and motor deficits in the median nerve distribution, not isolated EPL rupture.
Question 959
Topic: Wrist & Carpus
A distal radius fracture is stabilized with a volar locking plate. Compared to conventional non-locking plates, the stability of this locked construct relies primarily on which biomechanical mechanism?
Correct Answer & Explanation
. Fixed-angle coupling between the screw head and the plate
Explanation
Locked plates function as single-beam constructs where stability depends on the fixed-angle threaded coupling between the screw head and the plate hole. Unlike conventional plates, they do not rely on friction between the plate and the bone.
Question 960
Topic: 7. Hand and Wrist
A newborn is diagnosed with congenital scoliosis secondary to a fully segmented hemivertebra at T8. In addition to a comprehensive physical exam, which of the following screening tests is most critical?
Correct Answer & Explanation
. Renal ultrasound and echocardiogram
Explanation
Congenital scoliosis is highly associated with VACTERL anomalies. Renal ultrasound and echocardiography are critical screening tests to identify associated genitourinary and cardiac defects.
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