MCQs – Hand 5

Modern Study Review (AI-Generated)

High-Yield Summary

This topic is a staple of the Royal College exam, focusing heavily on hand tendon injuries, MCP joint biomechanics, nerve lesion localization, and tendon transfer principles. The single most important clinical trade-off is timing in FDP avulsion repair—intervention within 7-10 days avoids grafting, dictating surgical strategy. While classic exam answers emphasize rigid immobilization positions (e.g., MCP flexion for collateral ligaments), modern practice increasingly integrates early motion protocols to optimize outcomes. Understanding detailed anatomy (Guyon’s canal, deep fascial spaces) and biomechanical synergy is essential for both diagnosis and reconstructive surgery.

High-Yield Decision Matrix

Active Recall Q&A

EPL Rupture and Mallet Fracture

Q: What is the best treatment for attritional rupture of the EPL after a distal radius fracture?
A: Extensor Indicis Proprius (EIP) transfer.
Related Pearl: EIP transfer restores thumb extension with minimal donor morbidity, preserving hand dexterity.

Q: How are acute mallet fractures best treated?
A: With extension splinting.
Related Pearl: Maintaining terminal extensor tendon tension promotes healing without surgical intervention.

FDP Avulsion and Rotational Malunion

Q: What is the surgical window for FDP avulsions that retract into the palm?
A: 7-10 days; after this, grafting is often required due to tendon ischemia.
Related Pearl: Early repair preserves tendon viability and avoids complex reconstruction.

Q: How is rotational malunion of the fingers after metacarpal fracture best treated?
A: With metacarpal derotational osteotomy.
Related Pearl: Correcting rotation restores finger alignment and prevents functional impairment.

MCP Collateral Ligaments and Dislocations

Q: How do the MCP collateral ligaments behave during flexion and extension?
A: They act as cams—stretched in flexion and lax in extension.
Related Pearl: Immobilizing MCP joints in extension causes collateral shortening and loss of flexion.

Q: What is the recommended immobilization position for MCP collateral ligaments to prevent loss of motion?
A: Immobilize in flexion.
Related Pearl: Flexion maintains ligament length and preserves MCP joint mobility.

Q: What usually causes complex MCP dislocations?
A: Interposition of the volar plate.
Related Pearl: Volar plate entrapment prevents closed reduction, often necessitating open surgery.

Q: Which nerve is most at risk when volarly approaching a complex MCP dislocation?
A: The digital nerve.
Related Pearl: Careful dissection is essential to avoid iatrogenic nerve injury.

Radial Clubhand and Deep Fascial Spaces

Q: What is the most superficial structure to be cautious of during surgical approach to radial clubhand?
A: The median nerve, which is radially displaced and immediately subcutaneous.
Related Pearl: Misidentification risks median nerve injury and significant hand dysfunction.

Q: What are the boundaries of the two deep fascial spaces in the hand?
A: Thenar fascia radially, hypothenar fascia ulnarly; oblique septum from 3rd metacarpal divides midpalmar (medial) and thenar (lateral) spaces.
Related Pearl: Both spaces communicate with Parona’s space, a key route for infection spread.

Q: Where is Parona’s space located?
A: Between the deep flexors of the forearm and the anterior surface of pronator teres.
Related Pearl: Parona’s space is a potential pathway for proximal hand infection spread.

Ulnar Nerve Lesions and Guyon’s Canal

Q: What does loss of ulnar sensation with normal interosseous power indicate about lesion location?
A: Lesion at or distal to Guyon’s canal affecting the sensory branch.
Related Pearl: Sensory branch injury spares motor function, aiding lesion localization.

Q: What does loss of interosseous power with intact sensation suggest about lesion location?
A: Lesion at Guyon’s canal or between abductor digiti minimi and flexor digiti minimi muscles.
Related Pearl: Motor branch involvement without sensory loss helps differentiate lesion sites.

Q: What forms the boundaries of Guyon’s canal?
A: Medially: pisiform; laterally: hook of hamate; floor: transverse carpal ligament; roof: volar carpal ligament.
Related Pearl: Precise anatomy knowledge is critical for diagnosis and surgical decompression.

Scaphoid Blood Supply and Surgical Approaches

Q: What supplies blood to the scaphoid tuberosity?
A: Palmar branches of the radial artery.
Related Pearl: Tuberosity fractures generally heal well due to preserved blood supply.

Q: What supplies blood to the majority of the scaphoid?
A: Dorsal blood supply.
Related Pearl: The scaphoid waist is vulnerable to avascular necrosis due to retrograde flow.

Q: Through which structure does the volar Russe approach to the scaphoid pass?
A: The fibrous sheath of Flexor Carpi Radialis (FCR).
Related Pearl: Familiarity with this approach minimizes injury to tendons and neurovascular structures.

MCP Flexion and Wrist-Finger Synergy

Q: How does MCP flexion affect IP joint extension in intrinsic muscle paralysis?
A: MCP flexion allows long extensors to extend the IP joints.
Related Pearl: This principle guides rehabilitation and splinting in intrinsic muscle palsy.

Q: What is the synergy between wrist and finger movements?
A: Finger flexion synergizes with wrist extension; finger extension synergizes with wrist flexion.
Related Pearl: Synergistic tendon transfers leverage natural muscle coordination for better function.

Tendon Transfer Principles

Q: What are the key principles of tendon transfer regarding muscle power?
A: Donor muscle must have at least grade 4 power; expect a loss of one grade post-transfer.
Related Pearl: Strong donor muscles ensure adequate postoperative function.

Q: What must be corrected before performing a tendon transfer?
A: Joint contractures.
Related Pearl: Untreated contractures limit transfer effectiveness.

Q: What is required of tendon excursion in tendon transfers?
A: Adequate excursion to move the involved joint.
Related Pearl: Insufficient excursion results in limited postoperative range of motion.

Q: How should the transferred tendon be positioned?
A: In as straight a line of pull as possible.
Related Pearl: A straight line maximizes mechanical efficiency and function.

Q: How many functions should one transferred tendon ideally serve?
A: One tendon per function; avoid dual functions.
Related Pearl: Multipurpose transfers risk compromised function and failure.

Q: Why is synergism important in tendon transfers?
A: Transfers in phase (synergistic muscles) are preferred over out-of-phase transfers.
Related Pearl: Synergistic transfers facilitate motor relearning and improve outcomes.

Q: What is a critical donor tendon characteristic for transfer?
A: The tendon must be expendable.
Related Pearl: Using expendable tendons minimizes donor site morbidity.

Q: What tissue bed conditions optimize tendon transfer success?
A: Soft tissue induration resolved, no active wound reaction, supple joints, and soft scars.
Related Pearl: Transfers in scarred or inflamed beds have higher failure rates.

Q: Where should the tendon be passed during transfer?
A: Between subcutaneous fat and deep fascial layer, avoiding scar tissue.
Related Pearl: Proper routing prevents adhesions and preserves tendon gliding.

Classic Clinical Notes

• Attritional rupture of EPL after distal radius fracture is best treated with EIP transfer.

• Acute mallet fractures are best treated with extension splinting.

• For FDP avulsions that retract into the palm, all the blood supply to that tendon has been torn, and you have a window of 7-10 days to get at them. Waiting longer means that you’ll probably need a graft.

• Rotational malunion of the fingers after metacarpal fracture is best treated with metacarpal derotational osteotomy.

• The MCP collaterals act as cams, as they are stretched in flexion, lax in extension. If you immobilize them in extension, they contract and will not permit flexion. Hence, immobilize them in flexion! Loss of motion is related to collateral shortening.

• Complex MCP dislocations are usually caused by interposition of the volar plate.

• The digital nerve is most at risk when volarly approaching a complex MCP dislocation.

• The most superficial structure to be wary of when approaching a radial clubhand surgically is the median nerve – it is radially displaced and immediately subcutaneous.

• Remember that there are two deep fascial spaces in the hand – the outer boundaries are the thenar fascia radially, and the hypothenar fascia ulnarly. The oblique septum from the 3rd metacarpal divides this deep space into two spaces – the medial “midpalmar” space, and the lateral “thenar” space. Both communicate with Parona’s space which is the space between the deep flexors of the forearm and the anterior surface of pronator teres.

• If you lose ulnar sensation to the hand but have normal interosseous power, you’ve just lost the sensory branch – the lesion must be at or just distal to Guyon’s canal, where the deep and superficial branches divide. The deep branch is said to go through between the abductor digiti minimi and flexor digiti minimi. Conversely, if you lose interosseous power and have intact sensation, the lesion could be at Guyon’s or in between abductor digiti minimi and flexor digiti minimi.

• Guyon’s canal is formed by the pisiform medially, hook of hamate laterally, transverse carpal ligament (continuation of carpal tunnel roof) is the floor of the canal, and the volar carpal ligament (continuation of some forearm fascia) is the roof.

• With regards to scaphoid blood supply – the tuberosity receives its supply from the palmar branches of the radial artery. The remaining majority of the scaphoid gets its supply dorsally.

• The volar Russe approach to the scaphoid goes through the fibrous sheath of FCR.

• MCP flexion is most likely going to allow the long extensors to extend the IP joints of the hand when the intrinsics are paralyzed.

• There is “synergy” between wrist and fingers – synergy exists between finger flexion and wrist extension, and it exists between finger extension and wrist flexion (try this on your own hand and you’ll understand!). This concept is important when deciding about tendon transfers – ideally, you’d like to transfer tendons that are synergistic, because they will be acting “in phase”.

• Remember the principles of tendon transfer:
• Must correct joint contractures first
• The transferred muscle/tendon should have at least a solid grade 4 power – expect it to lose one grade
• The transferred tendon must have adequate excursion to move the involved joint
• The tendon should be transferred in as straight of a line of pull as possible
• Ideally, one tendon per function – do not try to motor two different functions with one tendon
• In phase transfer (synergism) is better than transferring tendons of muscles that work out of phase
• The tendon must be expendable!
• The tissue bed must be in equilibrium – soft tissue induration is gone, there is no further reaction in the wound, the joints are supple, the scars are as soft as they are going to be. Tendon transfers work best when passed between the subcutaneous fat and deep fascial layer, not when in the pathway of scar.

Last Updated on January 25, 2026 by Christian Veillette