What is the management guideline for a 3-week-old bony mallet finger?

Management of 3-Week-Old Bony Mallet Finger

For a 3-week-old bony mallet finger, initiate continuous splinting in extension for 8 weeks, as conservative management remains highly effective even for delayed presentations up to several weeks post-injury. 1, 2

Initial Assessment

Determine the fracture characteristics on radiography:

• Measure the size of the bony fragment relative to the articular surface 1
• Assess for palmar displacement of the distal phalanx 1
• Evaluate interfragmentary gap distance 1

Surgical indications include:

• Bony fragment involving >1/3 of the articular surface 1, 3
• Palmar displacement of the distal phalanx 1
• Interfragmentary gap >3 mm 1

Conservative Management (First-Line Treatment)

For fractures not meeting surgical criteria, proceed with splinting despite the 3-week delay:

• Immobilize the DIP joint in extension continuously for 8 weeks 4, 2
• Continue nighttime splinting for an additional 2 weeks 2
• Do not interrupt immobilization during this period 4
• Allow full active motion of the PIP and MCP joints 3

Splint options with evidence:

• Quickcast orthosis demonstrates fewer skin complications (33% vs 64%) and less pain (11.2 vs 21.6 on pain scale) compared to custom thermoplastic splints 5
• Both achieve equivalent functional outcomes regarding extensor lag 5

Expected outcomes with conservative management:

• Studies of chronic mallet fingers (4-18 weeks old) treated with 8 weeks of splinting achieved excellent results in 50% and good results in 40% of cases 2
• Mean final extension lag of 5-10 degrees is typical 6
• Recurrence occurs in approximately 20% of cases but responds to repeat 8-week splinting 2

Surgical Management

If surgical criteria are met, use modified extension-block K-wire technique:

• Place 2 dorsal extension-block K-wires with 1 transarticular K-wire (volar approach) 3
• This technique achieves 73% excellent and 21% good results by Crawford criteria 3
• Remove wires at 6 weeks when bridging trabeculae appear on radiographs 3
• Continue stock splint immobilization for additional 2 weeks post-wire removal 3
• Allow immediate active motion of PIP and MCP joints postoperatively 3

Complications of surgical approach:

• Nail ridging in 9% (resolves within 6 months) 3
• Mild scarring at pin sites in 6% 3
• Mild degenerative changes in some cases without functional limitation 3

Key Clinical Pitfalls

Avoid converting closed injuries to open procedures:

• Open surgical repair of soft tissue mallet injuries has unacceptable complication rates 4
• Percutaneous techniques are preferred if intervention is needed 6

Monitor for treatment failure:

• If splinting fails after 8 weeks, offer either repeat 8-week splinting trial or transarticular K-wire fixation 4
• Some patients will not tolerate repeat immobilization and require surgical intervention 4

The critical factor is uninterrupted immobilization:

• Patient compliance issues, decreased swelling, and hygiene concerns can lead to premature splint removal and unfavorable outcomes 6
• Consider percutaneous tenodermodesis (office-based suture technique) to prevent joint movement if compliance is questionable 6