MCQs – Hand 2

Modern Study Review (AI-Generated)

High-Yield Summary

Hand and thumb injuries, deformities, and dislocations are a staple of the Royal College exam, focusing heavily on anatomy-based decision-making and surgical indications. The critical clinical trade-off often lies between preserving function via tendon transfers or replantation versus recognizing injury patterns that contraindicate salvage (e.g., degloving amputations). For complex MCP dislocations, understanding the anatomical block to reduction dictates the surgical approach. While classic exam answers emphasize rigid rules for immobilization and tendon transfer choices, modern practice increasingly tailors interventions based on soft tissue viability and nerve function assessment.

High-Yield Decision Matrix

Active Recall Q&A

Thumb Injuries & Immobilization

Q: Why should you avoid immobilizing a gameskeeper thumb repair with the thumb metacarpal in adduction?
A: Because adducting the thumb metacarpal causes a webspace contracture and does not protect the repair.
Related Pearl: Maintaining thumb abduction preserves the first webspace, preventing contracture and optimizing functional recovery.

Digital Amputations

Q: Which digital amputations should be considered for replantation?
A: All thumbs, single digits amputated distal to the FDS insertion, and multiple digit injuries.
Related Pearl: Replantation success depends on intact tendon function and vascular supply distal to the injury.

Q: Which amputations should generally be avoided for replantation?
A: Avulsed, degloving-type amputations.
Related Pearl: These injuries have extensive soft tissue damage and poor vascular beds, reducing replant viability.

Intrinsic Hand Deformities

Q: What is the clinical presentation of an intrinsic plus contracture?
A: MCP joint flexion with IP joint extension.
Related Pearl: Reflects intrinsic muscle tightness or contracture affecting MCP flexion.

Q: What is the clinical presentation of an intrinsic minus contracture (clawing)?
A: MCP joint extension with IP joint flexion.
Related Pearl: Results from intrinsic muscle paralysis causing imbalance with long extensors and flexors.

Thumb Pulley Anatomy

Q: Which pulley is most important for thumb flexion?
A: The oblique pulley, analogous to the A2 pulley in fingers.
Related Pearl: It maintains tendon efficiency and prevents bowstringing during thumb flexion.

Imaging & Surgical Caution

Q: What imaging modalities best detect hook of hamate fractures?
A: CT scan and carpal tunnel views on X-ray.
Related Pearl: Standard wrist views often miss hook of hamate fractures; targeted imaging improves detection.

Q: What anatomical structure must be protected during hook of hamate excision?
A: The deep branch of the ulnar nerve.
Related Pearl: Injury causes intrinsic hand muscle paralysis and sensory deficits.

Tendon Transfers for Opposition

Q: What is the preferred tendon transfer for opponensplasty in low median nerve palsy?
A: FDS of the 4th finger, routed through a pulley made in the FCU tendon.
Related Pearl: FDS provides adequate power and excursion with minimal directional change, optimizing thumb opposition.

Q: What tendon transfer is recommended for opponensplasty in high median nerve palsy?
A: Extensor indicis transfer through the 3rd metacarpal interspace.
Related Pearl: High median nerve palsy involves FDS paralysis, necessitating alternative motor sources.

Deformity Pathophysiology

Q: How does a long-standing mallet deformity cause a swan neck deformity?
A: By lengthening the distal extensor mechanism, allowing dorsal migration of lateral bands at the PIP joint.
Related Pearl: Swan neck deformity results from imbalance between flexor and extensor forces at PIP and DIP joints.

Tendon Injury Diagnosis

Q: What does inability to flex the DIP joint after a finger cut 1 mm proximal to the distal flexion crease indicate?
A: The FDP tendon has been cut.
Related Pearl: FDP inserts distal to the distal flexion crease; loss of DIP flexion is a hallmark of FDP injury.

Q: What does inability to flex the PIP joint with other fingers held in extension suggest in this context?
A: Congenital absence of the FDS tendon.
Related Pearl: FDS has a broad insertion on the middle phalanx; isolated injury at this level is unlikely to completely disrupt PIP flexion.

Neuroma

Q: What is Wartenberg’s Syndrome?
A: A painful neuroma of the superficial radial nerve.
Related Pearl: Surgical excision and muscle burial of nerve ends can relieve symptoms if conservative treatment fails.

PIP Joint Anatomy

Q: Where are the collateral ligaments attached at the PIP joint?
A: Directly to the volar plate.
Related Pearl: This attachment stabilizes the PIP joint against lateral and volar forces.

Boutonniere Deformity

Q: What effect does contracture of the oblique retinacular ligament have on the DIP joint?
A: It causes an extension contracture of the DIP, limiting DIP flexion.
Related Pearl: The oblique retinacular ligament crosses volar to PIP and dorsal to DIP axes, influencing joint positions.

Q: Where does the oblique retinacular ligament lie relative to the PIP and DIP axes of rotation?
A: Volar to the PIP axis and dorsal to the DIP axis.
Related Pearl: This unique course explains its dual role in PIP flexion and DIP extension.

Q: Which structures are tight in a chronic Boutonniere deformity?
A: The oblique retinacular ligament (maintains DIP extension) and the transverse retinacular ligament (maintains PIP flexion).
Related Pearl: These tight ligaments perpetuate deformity by stabilizing abnormal lateral band positions.

Q: What happens to the triangular ligament in chronic Boutonniere deformity?
A: It becomes attenuated due to volar subluxation of the lateral bands.
Related Pearl: Triangular ligament attenuation contributes to lateral band instability and deformity progression.

Intrinsic Paralysis

Q: How do long extensors extend the IP joints when intrinsics are paralyzed?
A: They extend IP joints best with MCP joints held in flexion; without MCP flexion, they hyperextend MCPs and lose extension force on proximal phalanges.
Related Pearl: MCP flexion stabilizes the extensor mechanism, preventing MCP hyperextension and improving IP extension.

MCP Dislocation Surgery

Q: Which structure is most at risk during the open volar approach to complex MCP dislocation?
A: The neurovascular bundle.
Related Pearl: Careful dissection is required to avoid neurovascular injury and preserve finger viability.

Q: What clinical and radiographic signs indicate a complex MCP dislocation?
A: Skin dimpling, parallelism between metacarpal and proximal phalanx, and a sesamoid within a widened joint space.
Related Pearl: These signs suggest soft tissue interposition preventing closed reduction.

Q: What causes the block to reduction in complex MCP dislocations?
A: The metacarpal head is trapped between the lumbrical (radial side) and flexor tendons (ulnar side), creating a “Chinese finger trap,” with the volar plate as the primary block.
Related Pearl: Understanding this anatomy guides surgical release and successful reduction.

Classic Clinical Notes

• Do not immobilize a gameskeeper thumb injury/repair with the thumb metacarpal in adduction. This is not written anywhere, but I can’t imagine how this protects the repair. In addition, adducting the thumb metacarpal and keeping it there produces a webspace contracture!

• Digital amputations: try replanting all thumbs; single digits that have been amputated DISTAL to the FDS insertion, and multiple digit injuries. Avoid trying to replant an avulsed, degloving-type amputation.

• An intrinsic plus contracture or deformity usually shows up as MCP flexion, and IP joint extension. Intrinsic minus contracture (clawing) shows up as MCP extension, IP joint flexion.

• The oblique pulley is the most important structure supporting thumb flexion (akin to the A2 pulley of the finger).

• Hook of hamate fractures are best seen on CT or carpal tunnel views.

• When excising hook of hamate fractures, beware of the deep branch of the ulnar nerve.

• The best tendon transfer for opponensplasty is probably FDS of 4, brought through a little pulley made in FCU. (in the relevance of a low median nerve palsy, where opposition is severely limited by abductor pollicis brevis paralysis). “The motor has adequate power, more than sufficient excursion, and requires only slight change of direction by a pulley.” In high median nerve palsy, where FDS is also involved, probably have to do an extensor indices transfer through the 3rd metacarpal interspace.

• Swan neck deformity can occur as the result of a long-standing mallet deformity. The distal extensor mechanism is lengthened, and allows dorsal migration of the lateral bands at the PIP joint.

• If you cut your finger 1 mm proximal to the distal flexion crease and are unable to demonstrate DIP motion, you’ve cut the FDP. However, if you are also unable to demonstrate flexion of PIP with the other fingers held in extension, then you probably have a congenital absence of FDS, because 1 mm proximal to the distal flexion crease is probably still quite a bit distal to the broad insertion of FDS. Even if you got some of the FDS insertion, it is pretty broad, encompassing much of the volar surface of the middle phalanx – you are unlikely to have cut the whole tendon at this level, so close to the distal flexion crease.

• Wartenberg’s Syndrome is a painful neuroma of the superficial radial nerve. If bothersome enough, dissect out the ends, and bury them in muscle.

• The collateral ligaments are directly attached to the volar plate at the PIP joint.

• A contracture of the oblique retinacular ligament will cause an extension contracture of the DIP, thereby limiting DIP flexion (part of the pathophysiology of Boutonniere deformities.) The oblique retinacular ligament appears to lie volar to the axis of rotation of the PIP, but then curls dorsally to lie on dorsal to the axis of rotation of the DIP. When contracted (as in the Boutonniere deformity), it maintains the extension of the DIP. Because it lies volar to the axis of the PIP, it contributes to the flexion deformity of the PIP.

• The tight structures in a chronic Boutonniere deformity are the oblique retinacular ligament and the transverse retinacular ligament. The oblique retinacular ligament maintains the DIP extension, while the transverse retinacular ligament keeps the lateral bands subluxed volarly and maintains the PIP flexion. The oblique retinacular ligament, being volar to the axis of the PIP, also contributes to maintaining the PIP in flexion. The triangular ligament is attenuated because the lateral bands are pulled volarly.

• If the intrinsics are paralyzed, the long extensors are best able to extend the IP joints with the MCPs in flexion. If they are not held in flexion, the long extensors tend to hyperextend the MCPs and lose there extension force on the proximal phalanges.

• During the open volar approach to a complex MCP dislocation, the neurovascular bundle is most at risk.

• Complex MCP dislocations are associated with skin dimpling, parallelism between the metacarpal and proximal phalanx, and a sesamoid within a widened joint space.

• During the complex dislocation, the metacarpal head ruptures between the lumbrical radially and the flexor tendons ulnarly. These two create a Chinese finger trap that, when traction is applied, prevents the relocation of the head. The primary block to reduction, however, is the volar plate.

Last Updated on January 25, 2026 by Christian Veillette