Hand Surgery Practice Questions

Q: Madelung's deformity is characterized by an abnormality in which bone?

Distal radius. ***Distal radius*** - **Madelung's deformity** is primarily characterized by a **malformation of the distal radius**, specifically the physis (growth plate). - This leads to abnormal growth, causing the **radius to shorten and bow** dorsally, resulting in a prominent distal ulna. *Humerus* - The **humerus** is the bone of the upper arm, and abnormalities of this bone are not characteristic of Madelung's deformity. - Conditions affecting the humerus typically involve the shoulder or elbow joint, distinct from the wrist pathology seen in Madelung's. *Proximal ulna* - The **proximal ulna** forms part of the elbow joint, and while the ulna can be affected, the primary abnormality in Madelung's is in the radius. - While the ulna may appear prominent, this is secondary to the radial deformity, not a primary issue of the proximal ulna. *Carpals* - The **carpal bones** are located in the wrist, distal to the radius and ulna, and are not the primary site of deformity in Madelung's. - While wrist motion may be affected, the underlying cause is the abnormal growth of the distal radius, which can then impact carpal alignment.

Q: What is the primary use of a knuckle bender splint?

Ulnar nerve palsy. ***Ulnar nerve palsy*** - A knuckle bender splint is primarily used to counteract the characteristic **claw hand deformity** seen in ulnar nerve palsy [1] by maintaining the **metacarpophalangeal (MCP) joints** in flexion. - This splint helps improve function by preventing hyperextension of the MCP joints, which commonly occurs due to the unopposed action of the extensor muscles when the ulnar nerve is compromised. *Radial nerve palsy* - Radial nerve palsy typically results in **wrist drop** and an inability to extend the wrist and fingers, which is managed with wrist extension splints, not knuckle benders. - The primary goal of splinting in radial nerve palsy is to support the wrist in extension to facilitate grasping and carrying objects. *Median nerve palsy* - Median nerve palsy causes problems with thumb opposition and sensation in the first three and a half digits, often leading to an **ape hand deformity**. - Splints for median nerve palsy focus on maintaining the thumb in opposition, such as a **thumb spica splint**, which differs from a knuckle bender. *Axillary nerve palsy* - Axillary nerve palsy primarily affects the **deltoid muscle**, leading to weakness in shoulder abduction and external rotation. - Splinting for axillary nerve palsy typically involves shoulder immobilizers or abduction splints, which address shoulder joint positioning rather than hand function.

Q: Which of the following is NOT a symptom of carpal tunnel syndrome?

Ulnar nerve dysfunction. ***Ulnar nerve dysfunction*** - Carpal tunnel syndrome specifically involves compression of the **median nerve**, not the ulnar nerve. - Symptoms related to the median nerve include numbness and tingling in the **thumb, index, middle, and radial half of the ring finger**, along with **thenar muscle wasting**. *Tinel sign* - The **Tinel sign** is a common physical examination finding in carpal tunnel syndrome, elicited by tapping over the **median nerve** at the wrist. - A positive sign involves tingling or electric shock-like sensations in the **median nerve distribution**. *Phalen's sign* - **Phalen's sign** is another classic physical maneuver used to diagnose carpal tunnel syndrome, where exaggerated wrist flexion for 60 seconds reproduces symptoms. - This maneuver increases pressure within the **carpal tunnel**, exacerbating median nerve compression. *Pain & paraesthesia of wrist* - **Pain and paraesthesia (numbness and tingling)** in the wrist and hand are hallmark symptoms of carpal tunnel syndrome. - These symptoms are often worse at night or with repetitive hand movements, reflecting **median nerve irritation**.

Q: A 34-year-old female was operated for a fracture of the radial neck. Post-operatively, she was unable to extend her fingers at the metacarpophalangeal joints. There was no sensory loss in her hand. Which nerve is most commonly injured?

Posterior interosseous nerve. **Posterior interosseous nerve** - The inability to extend the fingers at the **metacarpophalangeal joints (MCP joints)**, without significant sensory loss in the hand, is characteristic of an injury to the **posterior interosseous nerve (PIN)**. - The PIN is a purely motor nerve that innervates the muscles responsible for MCP joint extension in the fingers, such as the digital extensors, and is vulnerable to injury during radial neck fractures or their surgical repair. *Radial Nerve* - A **radial nerve injury** would typically present with a **wrist drop** (inability to extend the wrist and fingers) and significant sensory loss in the **dorsal aspect of the hand**, which is not described. - While the PIN is a branch of the radial nerve, an injury limited to the PIN selectively affects motor function distal to its branching point, often sparing more proximal radial nerve functions and sensation. *Median Nerve* - A **median nerve injury** would primarily affect sensations in the **palmar aspect of the thumb, index, middle, and radial half of the ring finger**, and result in weakness or paralysis of the **thenar muscles** (e.g., opposition of the thumb). - It does not cause an inability to extend fingers at the MCP joints. *Anterior Interosseous nerve* - An **anterior interosseous nerve (AIN) injury** is also a purely motor deficit but affects the deep muscles of the forearm, leading to specific weaknesses in **flexion of the thumb IP joint** and the **index and middle finger DIP joints** (e.g., inability to make an "OK" sign). - It does not cause an inability to extend fingers at the MCP joints.

Q: Ulnar paradox is due to:

Flexor digitorum profundus (FDP). ***Flexor digitorum profundus (FDP)*** - The **ulnar paradox** occurs because a **distal ulnar nerve injury** (e.g., at the wrist) affects only the **intrinsic hand muscles** supplied by the ulnar nerve, sparing the **Flexor Digitorum Profundus (FDP)** to the ring and little fingers. - This allows the **FDP** (innervated by the ulnar nerve in its proximal forearm course, not at the wrist) to continue flexing the **distal interphalangeal (DIP) joints**, leading to a more pronounced **claw hand deformity** compared to a proximal injury. *Extensor carpi radialis brevis (ECRB)* - The **ECRB** is innervated by the **radial nerve** and is responsible for **wrist extension**, not affected in ulnar nerve injury. - It plays no direct role in the digital flexion deficits seen with ulnar nerve damage. *Radial nerve injury* - A **radial nerve injury** would predominantly affect the **extensors of the wrist and fingers**, leading to **wrist drop**, a completely different clinical presentation. - It does not cause a "claw hand" deformity or the effects on intrinsic hand muscles associated with the ulnar nerve. *Flexor pollicis longus (FPL)* - The **FPL** is innervated by the **anterior interosseous nerve**, a branch of the **median nerve**, and is responsible for **thumb IP joint flexion**. - Its function is unaffected by ulnar nerve lesions and is not involved in the ulnar paradox.

Q: A 54-year-old female marathon runner presents with pain in her right wrist that resulted from a fall onto her outstretched hand. Radiographic studies indicate an anterior dislocation of a carpal bone. Which of the following bones is most likely dislocated?

Lunate. ***Lunate*** - The **lunate bone** is the most commonly dislocated carpal bone, especially with a fall onto an **outstretched hand**. - Its central position in the proximal carpal row and its articulation with the radius make it vulnerable to **anterior dislocation** with forced dorsiflexion. *Capitate* - The **capitate** is the largest carpal bone but is more stable due to its central position and strong ligamentous attachments. - Isolated dislocation of the capitate is **rare** and usually accompanies other carpal injuries. *Trapezoid* - The **trapezoid** is a small, irregularly shaped carpal bone in the distal row, which is very stable. - Its strong articulations with the trapezium, capitate, and second metacarpal make its dislocation **extremely uncommon**. *Triquetrum* - The **triquetrum** is the second most commonly fractured carpal bone but is less prone to dislocation than the lunate. - While it can dislocate, it typically occurs with **ulnar impaction** or other complex carpal instabilities rather than an isolated anterior dislocation from a fall onto an outstretched hand.

Q: One of the common fractures that occur during boxing by hitting with a closed fist is:

Bennett's fracture dislocation. ***Bennett's fracture dislocation*** - This is an **intra-articular fracture** of the base of the **first metacarpal**, extending into the carpometacarpal (CMC) joint. - It is frequently caused by axial compression with the thumb in a flexed and adducted position, a common injury mechanism in **punching a hard object** during boxing. *Monteggia fracture dislocation* - This injury involves a fracture of the **proximal ulna** coupled with an **anterior dislocation of the radial head**. - It is typically caused by a direct blow to the forearm or a fall on an outstretched hand with a hyperpronated forearm, not a direct punch. *Galeazzi fracture dislocation* - This involves a fracture of the **distal radius** with an associated **dislocation of the distal radioulnar joint (DRUJ)**. - It results from a fall on an outstretched hand with a hyperpronated forearm, which is not consistent with a boxing injury. *Smith's fracture* - Also known as a **reverse Colles' fracture**, this is a fracture of the **distal radius** with **volar displacement of the distal fragment**. - It typically results from a fall on a flexed wrist or a direct blow to the back of the wrist, not a punching injury.

Q: Which carpal bone fracture causes median nerve involvement?

Scaphoid. ***Scaphoid*** - A fracture or dislocation of the **scaphoid bone** can lead to swelling and hematoma formation within the **carpal tunnel**, compressing the median nerve. - While less direct than lunate dislocations, **scaphoid fractures** can cause median nerve symptoms due to indirect pressure or callus formation. *Lunate* - A **dislocation of the lunate bone** (especially anterior displacement) is a hallmark cause of **acute carpal tunnel syndrome**, directly compressing the median nerve. - Unlike a fracture, the lunate's displacement itself physically reduces the space within the carpal tunnel, trapping the median nerve. *Trapezium* - Fractures of the **trapezium** are usually associated with injury to the **thumb carpometacarpal (CMC) joint** and do not typically cause median nerve involvement. - The trapezium is located more radially, outside the direct pathway of the median nerve in the carpal tunnel. *Trapezoid* - Fractures of the **trapezoid bone** are rare and typically stable, with little propensity to cause **median nerve compression**. - The trapezoid's anatomical position is deep within the wrist and away from the median nerve's primary pathway.

Q: A 30-year-old man involved in a fisticuff, injured his middle finger and noticed slight flexion of the distal interphalangeal (DIP) joint. X-rays were normal. The most appropriate management at this stage is:

Splint the finger in hyperextension. ***Splint the finger in hyperextension*** - The description of slight flexion of the **distal interphalangeal (DIP) joint** with normal X-rays after an injury suggests a **mallet finger**. This occurs due to rupture of the terminal extensor tendon, allowing unopposed flexion of the DIP joint. - The standard conservative treatment for **mallet finger** is continuous splinting of the DIP joint in slight **hyperextension** for 6 to 8 weeks, leaving the proximal interphalangeal (PIP) joint free. *Ignore* - Ignoring the injury is inappropriate as **mallet finger** will lead to a **permanent deformity** (extensor lag) and functional impairment if left untreated. - Early intervention with proper splinting provides a high success rate for tendon healing and restoration of function. *Surgical repair of the flexor tendon* - Surgical repair is indicated when the injury involves a **complex fracture**, severe subluxation, or chronic untreated cases of mallet finger that have failed conservative management. - The injury here affects the **extensor tendon**, not the flexor tendon, thus flexor tendon repair would be incorrect. *Buddy strapping* - **Buddy strapping** involves taping the injured finger to an adjacent healthy finger. This technique is primarily used for **phalangeal fractures** or dislocations to provide support and restrict movement. - For **mallet finger**, it would not adequately immobilize the DIP joint in hyperextension, which is crucial for healing the ruptured extensor tendon.

Q: What is the purpose of the Tinel sign?

To indicate nerve recovery. ***To indicate nerve recovery*** - A positive Tinel sign, noted as a tingling sensation felt distally to the point of percussion along the course of a nerve, is an indicator of **reinnervation** or **nerve regeneration**. - As the nerve regenerates, the advancing edge of nerve fibers becomes hypersensitive; thus, eliciting a Tinel sign further distally over time suggests **functional nerve recovery**. *To classify the type of nerve injury* - While a positive Tinel sign indicates ongoing nerve regeneration, it does not provide specific information to classify the **Seddon** (neuropraxia, axonotmesis, neurotmesis) or **Sunderland** (first- to fifth-degree) type of nerve injury. - nerve injury classification requires more comprehensive evaluation, including **electromyography (EMG)** and **nerve conduction studies (NCS)**, which distinguish between demyelination and axonal damage. *To locate the site of nerve injury* - The Tinel sign can help localize a **nerve compression** or **injury site** by identifying the point where percussion elicits tingling. - However, the primary purpose in the context of nerve injury is often to track the **progress of regeneration** rather than initially pinpointing the lesion. *To assess the severity of nerve damage* - The presence or absence of a Tinel sign does not quantify the **extent of nerve damage** (e.g., how many axons are damaged or the degree of demyelination). - Electrophysiological tests like **NCS** and **EMG** are better-suited for assessing the severity and type of nerve damage by measuring nerve conduction velocities and muscle responses.

Question 1

Madelung's deformity is characterized by an abnormality in which bone?

Accepted Answer

Distal radius

Answer

Humerus

Answer

Proximal ulna

Answer

Carpals

Question 2

What is the primary use of a knuckle bender splint?

Accepted Answer

Ulnar nerve palsy

Answer

Radial nerve palsy

Answer

Median nerve palsy

Answer

Axillary nerve palsy

Question 3

Which of the following is NOT a symptom of carpal tunnel syndrome?

Accepted Answer

Ulnar nerve dysfunction

Answer

Phalen's sign

Answer

Pain & paraesthesia of wrist

Answer

Tinel sign

Question 4

A 34-year-old female was operated for a fracture of the radial neck. Post-operatively, she was unable to extend her fingers at the metacarpophalangeal joints. There was no sensory loss in her hand. Which nerve is most commonly injured?

Accepted Answer

Posterior interosseous nerve

Answer

Radial Nerve

Answer

Median Nerve

Answer

Anterior Interosseous nerve

Question 5

Ulnar paradox is due to:

Accepted Answer

Flexor digitorum profundus (FDP)

Answer

Extensor carpi radialis brevis (ECRB)

Answer

Radial nerve injury

Answer

Flexor pollicis longus (FPL)

Question 6

A 54-year-old female marathon runner presents with pain in her right wrist that resulted from a fall onto her outstretched hand. Radiographic studies indicate an anterior dislocation of a carpal bone. Which of the following bones is most likely dislocated?

Accepted Answer

Lunate

Answer

Capitate

Answer

Trapezoid

Answer

Triquetrum

Question 7

One of the common fractures that occur during boxing by hitting with a closed fist is:

Accepted Answer

Bennett's fracture dislocation

Answer

Monteggia fracture dislocation

Answer

Galeazzi fracture dislocation

Answer

Smith's fracture

Question 8

Which carpal bone fracture causes median nerve involvement?

Accepted Answer

Scaphoid

Answer

Trapezium

Answer

Trapezoid

Answer

Lunate

Question 9

A 30-year-old man involved in a fisticuff, injured his middle finger and noticed slight flexion of the distal interphalangeal (DIP) joint. X-rays were normal. The most appropriate management at this stage is:

Accepted Answer

Splint the finger in hyperextension

Answer

Ignore

Answer

Surgical repair of the flexor tendon

Answer

Buddy strapping

Question 10

What is the purpose of the Tinel sign?

Accepted Answer

To indicate nerve recovery

Answer

To locate the site of nerve injury

Answer

To classify the type of nerve injury

Answer

To assess the severity of nerve damage

Hand Surgery — MCQs

Hand Surgery — MCQs

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