This practice set contains high-yield board review questions covering key concepts in Elbow & Forearm. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.
Question 1001
Topic: Elbow & Forearm
A 12-year-old baseball pitcher presents with chronic lateral elbow pain. Radiographs demonstrate focal radiolucency and fragmentation of the capitellum. What is the most likely diagnosis?
Correct Answer & Explanation
. Panner's disease
Explanation
OCD of the capitellum typically occurs in overhead athletes aged 11 to 15 years, presenting with lateral elbow pain and focal fragmentation. Panner's disease is an osteochondrosis of the entire capitellum but occurs in a younger age group (typically 7-10 years) and heals without fragmentation.
Question 1002
Topic: Elbow & Forearm
A 32-year-old male sustains a midshaft humerus fracture resulting in a complete radial nerve palsy. After 1 year, there is no clinical or electromyographic (EMG) evidence of recovery. A tendon transfer is planned to restore wrist extension. Which of the following is the most standard donor-recipient tendon transfer for this purpose?
Correct Answer & Explanation
. Pronator teres (PT) to Extensor carpi radialis brevis (ECRB)
Explanation
The pronator teres (PT) to extensor carpi radialis brevis (ECRB) transfer is the standard and most mechanically sound choice to restore wrist extension in radial nerve palsy. The ECRB is preferred over the ECRL because its central location on the carpus provides balanced wrist extension without inducing unwanted radial deviation.
Question 1003
Topic: Elbow & Forearm
A 42-year-old male undergoes surgical repair of a distal biceps tendon rupture via a single anterior incision. Post-operatively, he exhibits an inability to actively extend his metacarpophalangeal (MCP) joints and thumb interphalangeal joint, though tenodesis effect is intact. His wrist extension demonstrates radial deviation. Sensation is fully intact. Which nerve was most likely injured during the procedure?
Correct Answer & Explanation
. Posterior interosseous nerve
Explanation
The posterior interosseous nerve (PIN) is at risk during an anterior single-incision approach to the distal biceps, particularly with overzealous lateral retraction. A PIN palsy results in loss of active extension of the digits and thumb. Wrist extension results in radial deviation because the extensor carpi radialis longus (innervated by the radial nerve proper) remains functional while the extensor carpi ulnaris (PIN innervated) is paralyzed. Sensation remains intact.
Question 1004
Topic: Elbow & Forearm
A 45-year-old male undergoes surgical repair of a distal biceps tendon rupture using a single-anterior-incision technique with cortical button fixation. Postoperatively, he complains of numbness over the lateral aspect of his forearm. Injury to which of the following nerves is the most common complication of this specific surgical approach?
Correct Answer & Explanation
. Lateral antebrachial cutaneous nerve
Explanation
The lateral antebrachial cutaneous nerve (LABC) is highly susceptible to traction or iatrogenic injury during the single-anterior-incision approach to the distal biceps. In contrast, posterior interosseous nerve (PIN) injury or radioulnar synostosis is classically more associated with the two-incision technique.
Question 1005
Topic: Elbow & Forearm
A 45-year-old male falls from a ladder and sustains an isolated proximal ulna shaft fracture with an associated anterior dislocation of the radial head (Bado Type I Monteggia injury). During surgery, the ulna is anatomically reduced and plated, but the radial head remains persistently dislocated. What is the most likely interposing structure preventing reduction?
Correct Answer & Explanation
. Annular ligament
Explanation
In Monteggia fractures, anatomic restoration of ulnar length and alignment typically spontaneously reduces the radial head. If the radial head fails to reduce, the annular ligament or joint capsule is the most common interposing structure, requiring open reduction.
Question 1006
Topic: Elbow & Forearm
A 9-year-old male gymnast presents with lateral elbow pain and stiffness. Radiographs show sclerosis and fragmentation of the capitellum with an open proximal radial physis. An MRI confirms diffuse high T2 signal in the capitellum without a discrete osteochondral fragment. What is the most appropriate management?
Correct Answer & Explanation
. Rest, cessation of gymnastics, and symptomatic treatment
Explanation
The clinical presentation (age <10 years, typical radiographic findings without a discrete loose body) is classic for Panner's disease (osteochondrosis of the capitellum). Unlike osteochondritis dissecans (OCD) of the capitellum, which typically occurs in older adolescents and often requires surgery, Panner's disease is self-limiting. The standard treatment is conservative, consisting of rest and avoidance of inciting activities until symptoms resolve.
Question 1007
Topic: Elbow & Forearm
A 40-year-old recreational weightlifter undergoes surgical repair of an acute distal biceps tendon rupture via a single-incision anterior approach. Post-operatively, he complains of numbness and tingling along the lateral aspect of his forearm. Which nerve is most likely injured?
Correct Answer & Explanation
. Lateral antebrachial cutaneous nerve (LABCN)
Explanation
The lateral antebrachial cutaneous nerve (LABCN), which is the terminal sensory branch of the musculocutaneous nerve, exits deep to the biceps and lies in the subcutaneous tissue of the lateral forearm. Due to necessary lateral retraction during a single-incision anterior approach for distal biceps repair, the LABCN is the most commonly injured nerve, leading to lateral forearm paresthesias.
Question 1008
Topic: Elbow & Forearm
Which of the following is a recognized difference in complication profiles between the single-incision anterior approach and the two-incision (modified Boyd-Anderson) approach for distal biceps tendon repair?
Correct Answer & Explanation
. The single-incision approach has a higher rate of lateral antebrachial cutaneous nerve (LABCN) injury.
Explanation
The single-incision anterior approach requires deeper retraction, resulting in a higher risk of neurapraxia to the lateral antebrachial cutaneous nerve (LABCN) and radial nerve. Conversely, the two-incision approach (modified Boyd-Anderson) historically carries a higher risk of heterotopic ossification and radioulnar synostosis, although modern muscle-splitting techniques have mitigated this risk.
Question 1009
Topic: Elbow & Forearm
During the surgical management of a 'terrible triad' injury of the elbow, what is the generally accepted sequence of repair to restore joint stability?
Correct Answer & Explanation
. Coronoid fixation -> radial head fixation/replacement -> LCL repair
Explanation
The standard surgical sequence for a terrible triad injury (elbow dislocation, radial head fracture, coronoid fracture) works deep to superficial and medial to lateral (from a lateral approach): 1) Fixation of the coronoid process or anterior capsule repair, 2) Fixation or replacement of the radial head, and 3) Repair of the lateral collateral ligament (LCL) complex. The MCL is usually only repaired if instability persists after these steps.
Question 1010
Topic: Elbow & Forearm
A 40-year-old female sustains a coronal shear fracture of the distal humerus involving the capitellum. Radiographs and CT show a large fracture fragment consisting of articular cartilage and a thick layer of subchondral bone, with no extension into the trochlea. What is the correct Bryan and Morrey classification?
Correct Answer & Explanation
. Type I (Hahn-Steinthal)
Explanation
In the Bryan and Morrey classification: Type I (Hahn-Steinthal) is a large osseous articular fragment of the capitellum. Type II (Kocher-Lorenz) is a purely articular cartilage fragment with minimal subchondral bone. Type III (Broberg-Morrey) is a comminuted capitellum fracture. Type IV (McKee) involves a coronal shear fracture extending into the trochlea.
Question 1011
Topic: Elbow & Forearm
Posterolateral rotatory instability (PLRI) of the elbow typically results from an injury to the lateral ulnar collateral ligament (LUCL). What is the anatomic insertion of the LUCL?
Correct Answer & Explanation
. Supinator crest of the ulna
Explanation
The Lateral Ulnar Collateral Ligament (LUCL) is the primary restraint to posterolateral rotatory instability (PLRI). It originates on the lateral epicondyle and inserts distally on the supinator crest of the proximal ulna, acting as a supportive sling for the radial head.
Question 1012
Topic: Elbow & Forearm
A 45-year-old male sustains a comminuted, unsalvageable radial head fracture. Intraoperatively, marked proximal translation of the radius is noted when a longitudinal traction force is applied. Which of the following is the most appropriate management?
Correct Answer & Explanation
. Radial head arthroplasty and distal radioulnar joint (DRUJ) stabilization
Explanation
This patient has an Essex-Lopresti lesion (radial head fracture, interosseous membrane tear, and DRUJ disruption). Radial head excision alone is contraindicated as it will lead to proximal radial migration and chronic wrist pain. The correct treatment is a rigid metallic radial head arthroplasty to restore the longitudinal column, along with stabilization/pinning of the DRUJ.
Question 1013
Topic: Elbow & Forearm
A 14-year-old female gymnast presents with insidious onset of lateral elbow pain, clicking, and a 15-degree extension deficit. Radiographs demonstrate a radiolucent defect in the capitellum with a sclerotic margin and a loose body in the joint space. What is the most critical factor distinguishing this condition from Panner's disease?
Correct Answer & Explanation
. Age of the patient and presence of loose bodies
Explanation
This patient has Osteochondritis Dissecans (OCD) of the capitellum. It is crucial to distinguish OCD from Panner's disease (osteochondrosis of the capitellum). Panner's disease occurs in younger children (usually under 10 years old), is self-limiting, and does not form loose bodies. Capitellar OCD occurs in adolescents (typically 12-15 years old) and frequently results in loose body formation and long-term mechanical symptoms requiring surgery.
Question 1014
Topic: Elbow & Forearm
Posterolateral rotatory instability (PLRI) of the elbow primarily results from incompetence of the lateral ulnar collateral ligament (LUCL). What are the exact origin and insertion of the LUCL?
Correct Answer & Explanation
. Lateral epicondyle to the supinator crest of the ulna
Explanation
The lateral ulnar collateral ligament (LUCL) originates on the lateral epicondyle of the humerus, blends with the annular ligament, and inserts on the supinator crest of the proximal ulna. It acts as a posterior sling for the radial head, preventing posterolateral subluxation.
Question 1015
Topic: Elbow & Forearm
A surgeon utilizes a modified 2-incision (Mayo) approach for a distal biceps tendon repair. During the creation of the posterior window to retrieve and attach the tendon to the radial tuberosity, which of the following maneuvers is critical to prevent nerve injury?
Correct Answer & Explanation
. Maximal pronation to protect the posterior interosseous nerve
Explanation
In the modified 2-incision approach for a distal biceps repair, creating the posterior window (splitting the extensor carpi radialis brevis and extensor digitorum communis, or passing through the supinator) places the posterior interosseous nerve (PIN) at risk. The arm must be placed in maximal pronation; this rotates the radius and pulls the PIN medially, safely away from the posterior surgical field.
Question 1016
Topic: Elbow & Forearm
In a pediatric patient, understanding the chronological appearance of secondary ossification centers around the elbow is critical for accurately interpreting radiographs. According to the well-known CRITOE mnemonic, which of the following ossification centers appears last?
Correct Answer & Explanation
. External (lateral) epicondyle
Explanation
The secondary ossification centers of the pediatric elbow appear in a predictable sequence represented by the mnemonic CRITOE: Capitellum (1 year), Radial head (3 years), Internal (medial) epicondyle (5 years), Trochlea (7 years), Olecranon (9 years), and External (lateral) epicondyle (11 years). Thus, the lateral epicondyle is the last to appear.
Question 1017
Topic: Elbow & Forearm
A 35-year-old active individual develops elbow pain and stiffness. Imaging reveals Panner's disease in the capitellum. Years later, he presents with signs of advanced elbow osteoarthritis. How does Panner's disease predispose to later OA?
Correct Answer & Explanation
. It causes irregular ossification and potential collapse of the capitellum, altering joint mechanics.
Explanation
Panner's disease is an osteochondrosis of the capitellum in children, involving avascular necrosis and subsequent revascularization. This process can lead to an irregular, deformed, or sclerotic capitellum. Even after healing, the altered contour and underlying bone quality can significantly disrupt the normal radiocapitellar joint mechanics, leading to premature and accelerated development of osteoarthritis in adulthood. It does not primarily cause synovial inflammation, ligamentous laxity, ulnar nerve compression, or Type I collagen breakdown. The fundamental issue is the irreversible change in the articular surface contour and underlying subchondral bone, which creates an abnormal stress distribution in the joint.
Question 1018
Topic: Elbow & Forearm
Which of the following is a recognized complication specifically associated with radial head excision for radiocapitellar osteoarthritis?
Correct Answer & Explanation
. Distal radioulnar joint (DRUJ) instability
Explanation
Radial head excision removes the primary stabilizer of the proximal radius. While generally well-tolerated for isolated radiocapitellar OA, a recognized complication is proximal migration of the radius and subsequent distal radioulnar joint (DRUJ) instability, particularly if the interosseous membrane is compromised or the forearm axis is altered. Avascular necrosis of the capitellum is more associated with trauma or conditions like Panner's. Nonunion of the olecranon relates to osteotomy. Medial collateral ligament insufficiency is usually a primary pathology or complication of trauma/surgery that destabilizes the ulnohumeral joint. Heterotopic ossification can occur with any elbow surgery but is not specifically unique to radial head excision compared to other elbow procedures.
Question 1019
Topic: Elbow & Forearm
What is the primary role of the radial head in elbow stability?
Correct Answer & Explanation
. Secondary stabilizer to valgus stress and primary stabilizer to axial compression
Explanation
The radial head plays a crucial role as a secondary stabilizer to valgus stress (after the UCL) and is a primary stabilizer against axial compression loads across the humeroradial joint. It also contributes to varus stability. It is not the primary restraint to valgus or varus stress alone. While the annular ligament stabilizes the radial head for pronation/supination, the radial head itself isn't the primary stabilizer of these movements. The common extensor tendon originates from the lateral epicondyle, not the radial head.
Question 1020
Topic: Elbow & Forearm
Which of the following anatomical structures is most commonly responsible for anterior elbow impingement symptoms?
Correct Answer & Explanation
. Coronoid process hypertrophy
Explanation
Anterior elbow impingement symptoms, often presenting as pain and limited extension, are most commonly caused by hypertrophy of the coronoid process (or its osteophytes) impinging against the coronoid fossa of the humerus. Olecranon osteophytes cause posterior impingement. Radial head hypertrophy can cause symptoms, but less typically anterior impingement. Medial epicondyle spurs are associated with UCL pathology, and capitellum defects with OCD, not primary anterior impingement.
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