What is the recommended management for a comminuted fracture of the second metacarpal with dorsal angulation?

Treatment of Comminuted Fracture of Second Metacarpal with Dorsal Angulation

For a comminuted second metacarpal fracture with dorsal angulation, surgical fixation is strongly recommended if dorsal angulation exceeds 10 degrees, as the index and middle fingers tolerate minimal angulation before losing grip strength. 1, 2

Surgical Indications for Second Metacarpal Fractures

The second metacarpal requires more stringent reduction criteria than ulnar digits due to limited compensatory motion at the carpometacarpal joint:

• Dorsal angulation >10 degrees is an absolute indication for operative fixation 1
• Any rotational malalignment requires surgical correction 3
• Shortening >3mm necessitates operative treatment 1
• Intra-articular step-off >2mm requires surgical intervention 1

The radial digits (index and middle fingers) cannot tolerate the same degree of angulation as the fourth and fifth metacarpals because they lack the compensatory carpometacarpal mobility that ulnar digits possess. 2

Optimal Fixation Technique for Comminuted Fractures

For comminuted fractures specifically, intramedullary headless screw fixation is the preferred technique over dorsal plating, as it provides stable fixation while avoiding the high complication rates associated with plate fixation in comminuted patterns. 4, 3

Fixation Options in Order of Preference:

1. Intramedullary headless compression screws - Allows immediate active mobilization with excellent functional outcomes and no hardware prominence 4, 3

   • Achieves union in all cases with <5 degrees rotational/axial deformity 4
   • Permits return to work within 2.38 weeks on average 4
   • No cases of CRPS, tendon adhesions, or hardware complications reported 4

2. Percutaneous K-wire fixation - Acceptable alternative with lower complication rates than plating 5

   • Demonstrates better range of motion (89.74°) compared to screw (80°) or plate (80.2°) fixation 5
   • Achieves 94% normal grip strength versus 80-82% with other methods 5
   • Lower postoperative pain scores 5

3. Dorsal plate fixation - Reserved only when other techniques are not feasible 2, 5

   • Complication rates up to 36% with plate and screw constructs 2
   • Higher rates of tendon adhesions and hardware prominence 5
   • However, may be necessary in severely comminuted fractures where intramedullary fixation cannot achieve adequate stability 2

Critical Post-Operative Management

Immediate active finger motion exercises must begin within 0-3 days post-operatively to prevent stiffness, which is the most functionally disabling complication. 4, 6

• Buddy strapping to adjacent finger allows protected early mobilization 4
• Active motion of all finger joints (MCP, PIP, DIP) should start immediately while maintaining fracture stability 6, 7
• Wrist immobilization is not necessary following stable metacarpal fixation 8

Common Pitfalls to Avoid

Do not underestimate acceptable angulation limits in the second metacarpal - Unlike the fifth metacarpal which tolerates 30-40 degrees of dorsal angulation, the second metacarpal loses significant grip strength with >10 degrees angulation. 1, 2

Avoid prolonged immobilization - Stiffness is the most disabling complication and results from delayed mobilization rather than the surgical technique itself. 6, 9

Do not rely on closed reduction and casting for comminuted fractures - Comminuted patterns are inherently unstable and will lose reduction with non-operative management. 6, 2

Avoid dorsal plating as first-line treatment - The high complication rate (up to 36%) makes it a less favorable option unless comminution precludes intramedullary fixation. 2, 5

Follow-Up Protocol

• Radiographs at 3 weeks post-operatively to confirm maintained reduction 6
• Clinical assessment of rotation by observing finger cascade with flexion - all fingertips should point toward scaphoid tubercle 3
• Functional outcome assessment at 4-6 weeks, expecting total active motion >240 degrees 3
• Monitor for delayed complications including malunion, which may require corrective osteotomy if symptomatic 9