MCQs – Hand 3

Modern Study Review (AI-Generated)

High-Yield Summary

Wrist and hand injuries, including tendon avulsions, carpal instability, and degenerative conditions, are a staple of orthopaedic board exams, focusing heavily on timing of intervention and biomechanical understanding. The critical clinical decision often hinges on injury chronicity (e.g., <3 weeks for scapholunate repair, early surgery for FDP avulsion) and radiographic thresholds (e.g., >3 mm scapholunate gap). While classic teaching emphasizes early fixation and conservative splinting durations, modern practice increasingly integrates nuanced biomechanical insights and tailored fusion options to preserve function. Understanding ligamentous contributions to deformities like VISI and the vascular anatomy protecting the lunate in perilunate dislocations is essential for accurate diagnosis and management.

High-Yield Decision Matrix

Active Recall Q&A

Tendon Injuries

Q: When should Jersey finger (FDP avulsion) be surgically approached?
A: As early as possible, especially if the tendon retracts all the way into the palm.
Related Pearl: Delayed repair increases tendon retraction and scarring, complicating reconstruction and reducing functional outcomes.

Q: How long after injury can mallet fingers be treated with splinting?
A: Up to 12 weeks after the initial injury.
Related Pearl: Prolonged splinting maintains DIP joint extension, allowing tendon healing without surgical intervention.

Osteoarthritis and Fractures

Q: Which joint is most commonly affected by degenerative osteoarthritis in the wrist?
A: The trapeziometacarpal joint.
Related Pearl: Its high mobility and load-bearing function predispose it to OA, especially in thumb-dominant activities.

Q: What is the debated second most common joint affected by wrist OA after the trapeziometacarpal joint?
A: Radioscaphoid joint or scaphotrapezial joint.
Related Pearl: Scaphotrapezial OA often coexists with trapeziometacarpal OA, complicating clinical assessment and treatment.

Q: What is the best management for a volar Barton’s fracture?
A: Volar ORIF with a buttress plate.
Related Pearl: Volar plating restores articular congruity and prevents volar fragment displacement, critical for wrist stability.

Nerve and Tendon Support

Q: How should treatment for carpal tunnel syndrome be guided?
A: Based on clinical findings; NCS and EMG can be normal and do not rule out the diagnosis.
Related Pearl: Electrodiagnostic tests have false negatives early in disease; clinical diagnosis remains paramount.

Q: What is the function of the sagittal bands in the hand?
A: They tether and support the long extensor tendons over the metacarpophalangeal (MCP) joints.
Related Pearl: Sagittal band rupture leads to extensor tendon subluxation and impaired finger extension.

Keinbock’s Disease

Q: How can early Keinbock’s disease (pre-collapse stages I, II, IIIA) be treated?
A: Radial shortening, ulnar lengthening, or scapho-trapezio-trapezoid (STT) fusion.
Related Pearl: These procedures address ulnar variance and offload the lunate to prevent collapse progression.

Q: What is the probable etiology of Keinbock’s disease?
A: Microtrauma combined with an aberrant blood supply in 20% of the population.
Related Pearl: Ulnar minus variance increases lunate load, predisposing to avascular necrosis.

Wrist Biomechanics

Q: What happens to the scaphoid and lunate during radial deviation?
A: Both flex.
Related Pearl: This biomechanical behavior influences carpal kinematics and injury patterns.

Q: What happens to the scaphoid and lunate during ulnar deviation?
A: Both extend.
Related Pearl: Understanding these movements aids in interpreting wrist radiographs and diagnosing instability.

Q: What is the normal carpal height ratio?
A: 0.54 ± 0.03.
Related Pearl: A decreased ratio suggests carpal collapse or degenerative changes.

Perilunate and SLAC Wrist

Q: What is the most common nerve injury after perilunate dislocation?
A: Median nerve compression.
Related Pearl: Early recognition and decompression are critical to prevent permanent nerve damage.

Q: What are the stages of SLAC wrist progression?
A: Radial styloid ? radioscaphoid ? scaphocapitate ? capitolunate involvement.
Related Pearl: Radiolunate fossa is typically spared until late, guiding surgical options.

Q: What limited fusion options exist for SLAC wrist?
A: STT fusion, scaphocapitate (SC) fusion, and four corner fusion with scaphoid excision.
Related Pearl: These preserve some wrist motion while addressing instability and pain.

Ligamentous Injuries and Deformities

Q: What ligament injuries contribute to VISI deformity?
A: Lunatotriquetral ligament tear plus dorsal radiocarpal ligament injury.
Related Pearl: Both ligamentous structures are often required to produce VISI deformity; isolated tears may be insufficient.

Scaphoid Malunion and Scapholunate Injury

Q: How is a 9-month-old scaphoid malunion with DISI deformity treated?
A: Fernandes procedure: volar approach, intercalary bone graft, and Herbert screw fixation.
Related Pearl: The Fernandes procedure restores scaphoid length and corrects deformity to prevent arthritis.

Q: When should a scapholunate injury be treated with open reduction and internal fixation?
A: Within 3 weeks of injury and before progression past stage I SLAC.
Related Pearl: Early fixation improves ligament healing and prevents chronic instability.

Q: What are radiographic signs of scapholunate dissociation?
A: Widened scapholunate space >3 mm, shortened scaphoid with ring sign, triangular lunate, and DISI deformity on lateral X-ray.
Related Pearl: Recognizing these signs is critical for early diagnosis and management.

Mechanism and Vascularity

Q: What is the mechanism of perilunate dislocations?
A: Hyperextension injury.
Related Pearl: High-energy trauma causes ligament disruption and carpal instability.

Q: Why is avascular necrosis of the lunate unusual in perilunate dislocations?
A: Because the volar radiolunate ligament preserves blood supply to the lunate.
Related Pearl: Preservation of volar ligamentous blood supply reduces risk of lunate necrosis despite dislocation.

Classic Clinical Notes

• Jersey fingers (FDP avulsions) should be approached as early as possible, especially if the tendon retracts all the way into the palm.

• Mallet fingers can be treated with splinting up to 12 weeks after initial injury.

• The trapeziometacarpal joint is the most commonly affected joint in the wrist (with degenerative OA).

• After that, may be most common in the radioscaphoid joint – a debatable thing. Not sure if this is more common than scaphotrapezial. Scaphotrapezial OA is often associated with trapeziometacarpal OA, which is exceedingly common.

• The best management of a Barton’s fracture (volar, intra-articular fracture of the distal radius) is ORIF volarly with buttress plate.

• Patients with carpal tunnel syndrome should have their treatment based on clinical findings. Do not rely on NCS and EMG which can both be normal and do not rule out the diagnosis.

• The sagittal bands help tether and support the long extensors over the MCP.

• Early Keinbock’s disease can be treated with radial shortening, ulnar lengthening, or STT fusion. By “early”, I think they mean pre-collapse (I, II, or IIIA) – all of these can be treated by dealing with the ulnar variance, and perhaps with limited wrist fusion (STT) or PRC.

• Etiology of Keinbock’s – probably microtrauma. 20% of the population has an aberrant blood supply (not 30%). Ulnar minus variance is a predisposing factor.

• When radially deviating, the scaphoid and lunate flex; when ulnarly deviating, they both extend.

• The carpal height ratio is .54 +/- .03.

• The most common nerve injury after perilunate dislocation is median nerve compression.

• In SLAC wrist, depending on the stage and involvement of the joints, you can do a radial styloidectomy, scaphoid excision and 4 corner fusion, proximal row carpectomy, or (if radiocarpal and midcarpal involvement) total wrist fusion. Remember, the radiolunate fossa is almost always preserved until very late in the course of disease. (This is why you can get away with a radial excision and 4 corner fusion – because the radiolunate fossa is okay).

• Remember: SLAC starts at radial styloid with distal scaphoid vs radial styloid degeneration. Then progresses to diffuse radioscaphoid involvement, then to scaphocapitate involvement, then capitolunate involvement (which signifies midcarpal collapse).

• Limited fusions possible for SLAC wrist include STT, SC, and four corner with scaphoid excision.

• Lunatotriquetral dissociation leads to VISI deformity.

• The dorsal radiocarpal ligaments are also important in the development of the VISI deformity – some feel that a lunatotriquetral ligament tear alone is insufficient to create the VISI deformity, and that the dorsal radiocarpal ligaments must also be torn. Some say that tearing the dorsal radiocarpal ligaments alone can cause a VISI deformity too!

• A 9 month old scaphoid malunion with DISI deformity – treat with Fernandes procedure: volar approach, intercalary bone graft, Herbert screw. (Russe is a non-instrumented inlay bone graft)

• A patient 3 weeks out with a scapholunate injury should probably undergo open reduction and internal fixation. Should probably try fixing these as long as they have not progressed past stage I SLAC (in stage I SLAC you do the radial styloidectomy and fix the scapholunate ligament)

• Signs of scapholunate dissociation: widened S-L space (>3 mm), shortened scaphoid with ring sign, triangular lunate, DISI deformity on lateral x-ray.

• Perilunate dislocations are caused by hyperextension.

• Avascular necrosis of the lunate is unusual in perilunate dislocations because the volar ligamentous blood supply is maintained to the lunate (volar radiolunate ligament).

Last Updated on January 25, 2026 by Christian Veillette