MCQs – Hand 4

Modern Study Review (AI-Generated)

High-Yield Summary

This topic is a staple of the Royal College exam, focusing heavily on wrist biomechanics, hand ligament anatomy, and common pathologies such as scaphoid fractures, Dupuytren’s contracture, and thumb MCP stability. The single most important clinical trade-off often tested is the interpretation of ulnar variance on X-rays, where forearm rotation critically alters measurement accuracy, influencing diagnosis and treatment decisions. While classic teaching emphasizes fixation of all scaphoid nonunions, modern practice increasingly incorporates adjunctive therapies like electromagnetic stimulation for select undisplaced cases. Understanding the dynamic and static stabilizers of the thumb MCP joint is essential for managing valgus injuries, as injury patterns extend beyond the classic UCL tear.

High-Yield Decision Matrix

Active Recall Q&A

Ulnar Variance and Wrist Arthritis

Q: How does forearm rotation affect the appearance of ulnar negative variance on X-rays?
A: Supination exaggerates ulnar negative variance by making the radius appear longer; pronation underestimates it by shortening the radius relative to the ulna.
Related Pearl: Neutral forearm rotation with shoulder and elbow flexed to 90° is the standard for accurate ulnar variance measurement to avoid misdiagnosis.

Q: Which fossa is preserved in both SLAC and SNAC wrists?
A: The radiolunate fossa is preserved in both SLAC and SNAC wrists.
Related Pearl: Preservation of the radiolunate fossa helps differentiate these degenerative patterns from other wrist arthritis types.

Scaphoid Fractures and Nonunion

Q: What is the natural history of untreated scaphoid nonunions according to the literature?
A: Untreated scaphoid nonunions have a poor natural history, supporting fixation even if undisplaced.
Related Pearl: Early fixation with bone grafting or electromagnetic stimulation improves healing and prevents collapse.

Q: How do proximal and distal pole scaphoid fractures differ in healing?
A: Proximal pole fractures heal poorly; distal pole (tuberosity) fractures heal well.
Related Pearl: Proximal pole fractures have limited blood supply, increasing nonunion risk.

Dupuytren’s Contracture

Q: What are the three pathologic cords in Dupuytren’s contracture?
A: Central cord, spiral cord, and lateral cord.
Related Pearl: The spiral cord is clinically important as it pulls the neurovascular bundle centrally, increasing risk during surgery.

Q: What is the management if palmar skin cannot be closed after partial fasciectomy for Dupuytren’s?
A: The palmar skin can be left open; however, finger skin must be closed.
Related Pearl: Finger skin closure is critical to prevent contracture and maintain function.

Q: Which Dupuytren’s contracture deformity is hardest to treat?
A: PIP joint contracture is the hardest to treat.
Related Pearl: Early intervention at the onset of PIP contracture improves outcomes.

Scaphoid Malunion and Wrist Motion

Q: What wrist motion is inhibited by a malunited scaphoid fracture?
A: Dorsiflexion is usually inhibited.
Related Pearl: Scaphoid malunion alters carpal kinematics, limiting wrist extension.

Lunate-Triquetral Injury and VISI Deformity

Q: Do isolated lunatotriquetral injuries cause VISI deformities?
A: No; VISI deformities require additional tears of palmar lunatotriquetral, dorsal radiotriquetral, or palmar ulnar ligaments.
Related Pearl: Complex ligamentous injury is necessary for VISI; isolated LT tears are insufficient.

Thumb Key Pinch Stabilizers

Q: What is the primary static stabilizer of the thumb during key pinch?
A: The MCP collateral ligaments.
Related Pearl: Injury to these ligaments compromises pinch strength and stability.

Q: What is the primary dynamic stabilizer of the thumb during key pinch?
A: The adductor pollicis muscle.
Related Pearl: The adductor pollicis dynamically maintains MCP joint stability during pinch.

Q: How do static stabilizers of the thumb MCP vary with joint position?
A: In flexion, collateral ligaments are primary stabilizers; in extension, accessory collateral ligaments and palmar plate resist valgus stress.
Related Pearl: Valgus injuries often occur in extension, implicating accessory structures beyond the UCL.

Q: Why is the palmar plate and accessory collateral ligaments’ role important in thumb MCP valgus injuries?
A: Because valgus force is applied in extension, these structures may also be injured but are often overlooked.
Related Pearl: Comprehensive assessment of all stabilizers is essential in thumb MCP injuries.

Q: What structures form the dynamic stabilizers of the thumb MCP?
A: Extrinsic and intrinsic muscles; the adductor mechanism is key; the extensor hood includes EPL, EPB, sagittal bands, and adductor aponeurosis.
Related Pearl: The extensor hood coordinates extension and stability during thumb motion.

1st Metacarpal Base Fractures

Q: How should extra-articular base of 1st metacarpal fractures be managed regarding angulation?
A: They tolerate considerable angulation; overtreatment should be avoided.
Related Pearl: Functional outcomes often remain good despite deformity due to compensatory thumb mobility.

Flexor Tenosynovitis

Q: What is the most common pathogen in flexor tenosynovitis?
A: Staphylococcus aureus.
Related Pearl: Early antibiotic coverage targeting Staph aureus is critical to prevent tendon necrosis.

Carpal Bone Pain

Q: What can occult intraosseous ganglia cause in the carpal bones?
A: They can cause pain, especially in the scaphoid.
Related Pearl: MRI or CT may be needed to detect these subtle lesions causing unexplained wrist pain.

Dupuytren’s Anatomy

Q: Which ligaments are not typically involved in Dupuytren’s contracture?
A: Cleland’s ligament (dorsal to neurovascular structures) is not involved.
Related Pearl: The spiral band wraps volar to the neurovascular bundle, sparing dorsal structures like Cleland’s ligament.

Annular Pulleys

Q: From where do annular pulleys A1 and A3 arise?
A: They arise from the volar plate, not the phalanges.
Related Pearl: This anatomical detail is important in pulley reconstruction and trigger finger release.

DRUJ Stability and TFCC

Q: What is the most important stabilizer of the distal radioulnar joint (DRUJ)?
A: The triangular fibrocartilage complex (TFCC).
Related Pearl: TFCC injuries are a common cause of DRUJ instability and ulnar-sided wrist pain.

Q: What are the components of the TFCC?
A: 2 cartilaginous structures (articular disc, meniscal homologue) and 5 ligamentous structures (dorsal and volar radioulnar ligaments, ulnolunate ligament, ulnotriquetral ligament, ECU sheath).
Related Pearl: Understanding TFCC anatomy guides surgical repair and arthroscopic evaluation.

Classic Clinical Notes

• In an ulnar negative wrist, supination makes the ulnar negative variance appear worse. Conversely, pronation will tend to underestimate it; remember – supination brings the radius out longer; pronation shortens it relative to the ulna. X-rays should therefore be taken in neutral forearm rotation with the shoulder and elbow flexed to 90.

• Like SLAC wrist, the radiolunate fossa is preserved in SNAC wrist.

• The literature would support that left untreated, the natural history of scaphoid nonunions is bad – this may or may not be true, but it is what the literature tells us. Therefore, an undisplaced scaphoid nonunion should probably be fixed – either bone grafted or subjected to electromagnetic fields.

• Proximal pole scaphoid fractures heal poorly; distal pole (tuberosity) fractures heal well.

• There are three pathologic cords that develop in Dupuytren’s – central cord, spiral cord, and lateral cord – the spiral cord pulls the neurovascular bundle centrally.

• If you are unable to close palmar skin after a partial fasciectomy for Dupuytren’s – you can leave it open. In the finger, you have to get the skin closed.

• In Dupuytren’s it is much harder to treat the PIP contracture than anything else (hence, you should probably try to do these when the PIP starts to get contracted.)

• A malunited scaphoid fracture will usually result in inhibited DORSIflexion.

• Isolate lunatotriquetral injuries usually do not cause VISI deformities – studies have shown that a tear of the palmar lunatotriquetral ligament, dorsal radiotriquetral ligament, or palmar ulncarpal ligaments is necessary also. I don’t think anyone is really sure what is required before these tear, but it seems to be accepted that you need more than lunatotriquetral injury.

• For key pinch, the primary static stabilizer is the MCP collateral ligaments; the primary dynamic stabilizer is the adductor pollicis.

• The static stabilizers of the thumb MCP are the collateral ligaments, accessory collateral ligaments, the palmar plate, and dorsal capsule – their relative importance depends on the position of the MCP joint. In flexion, the collateral ligaments are the primary joint stabilizers. In extension, the accessory collateral ligaments and palmar plate are taut and are the primary joint stabilizers against valgus stress. (That’s interesting, because when a valgus force is applied, the thumb normally is extension and yet we concern ourselves with the main UCL injury). Perhaps the palmar plate and accessory collaterals are also torn, and we just don’t bother dealing with them.

• The dynamic stabilizers of the thumb include the extrinsics and intrinsics. The adductor mechanism is of particular importance as a dynamic stabilizer. The extensor hood is formed by EPL, EPB, the sagittal bands, and the adductor aponeurosis.

• Base of 1st metacarpal fractures that are extra-articular tolerate quite abit of angulation and one should resist overtreating them.

• The most common bug in flexor tenosynovitis is staph aureus.

• Occult intra-osseous ganglia can cause pain in the carpal bones – watch out for them in the scaphoid.

• The Dupuytren’s contracture does not typically involve Cleland’s ligament (dorsal to the NV structures in the finger). The pathologic cord involves the palmar fascia, natatory ligament, spiral band, and Greyson’s ligament (volar to the NV structures in the finger). A good way to remember this is that the spiral band moves from volar to dorsal to the NV structures, then emerges in the finger VOLARLY, thereby wrapping up the NV bundle and pulling it centrally. If it went dorsally to involve Cleland’s, it would not have this effect on the NV bundle.

• The annular pulleys 1 and 3 arise from the volar plate and do not arise from the phalanges. Remember the order: A1, A2, C1, A3, C2, A4, C3, A5

• The most important stabilizer of the DRUJ is the TFCC.

• The TFCC consists of articular disc, meniscal homologue, dorsal radioulnar ligament, volar radioulnar ligament, ulnolunate ligament, ulnotriquetral ligament, sheath of ECU (2 cartilaginous structures, 5 ligamentous structures).

Last Updated on January 25, 2026 by Christian Veillette