Mallet Finger: Diagnosis and Conservative Management with Continuous Splinting
This is a classic mallet finger injury requiring immediate splinting of the DIP joint in extension for 6-8 weeks without interruption, as even brief splint removal restarts the healing timeline. 1, 2
Diagnosis
The clinical presentation confirms mallet finger—a disruption of the terminal extensor tendon at the distal phalanx insertion causing inability to actively extend the DIP joint while passive extension remains intact. 3, 4
Key Diagnostic Features:
- Flexed distal phalanx with inability to actively extend the DIP joint 3
- Passive extension is possible but cannot be maintained once released 3
- Swelling and pain at the DIP joint are typical 4
- X-ray is mandatory to differentiate between tendinous (no fracture) versus bony mallet finger (avulsion fracture at the base of the distal phalanx) 5, 1, 4
Since your X-ray shows no fracture, this is a tendinous mallet finger (Doyle Type I), which represents the majority of closed mallet injuries. 3, 2
Treatment Algorithm
Conservative Management (First-Line for Tendinous Mallet):
Immediate splinting is critical—the American College of Radiology and American Heart Association emphasize that uninterrupted immobilization is essential, as even brief splint removal can restart the entire healing timeline. 1
Splinting Protocol:
- Apply a dorsal or volar splint maintaining the DIP joint in extension (NOT hyperextension for tendinous injuries—slight hyperextension is reserved for bony avulsions) 1, 4, 6
- Duration: 6-8 weeks of continuous wear, followed by an additional 2-4 weeks of nighttime splinting 2, 6
- The PIP joint should remain free to prevent stiffness 6
- Patient compliance is paramount—educate that any flexion during the healing period restarts the clock 1, 4
Initial Symptom Management:
- Apply ice-water mixture for 10-20 minutes with a thin towel barrier to reduce swelling 1
- Avoid heat application and do not attempt to manually straighten the finger before proper splinting 1
Surgical Indications (NOT applicable to this case):
Surgery is generally reserved for: 2, 6, 7
- Open injuries
- Avulsion fractures involving ≥1/3 of the articular surface 5, 2, 6
- Palmar subluxation of the distal phalanx (>3mm interfragmentary gap or irreducible subluxation) 5, 4
- Failed conservative treatment after appropriate splinting duration 2, 6
Critical Pitfalls to Avoid
- Do not allow any DIP joint flexion during the 6-8 week healing period—this is the most common cause of treatment failure 1, 4
- Do not use MRI or CT for routine mallet finger diagnosis—standard radiographs are sufficient per the American College of Radiology 1
- Warn patients that untreated or inadequately treated mallet finger leads to chronic deformity, swan-neck deformity, and DIP joint osteoarthritis 4, 6
- Ensure proper splint fit—skin breakdown and pressure sores can occur with poorly fitted splints 6
Expected Outcomes
Conservative treatment with proper splinting yields good results in the majority of tendinous mallet finger cases, minimizing morbidity while restoring active DIP extension. 2, 6 However, outcomes are highly dependent on patient compliance with the uninterrupted splinting protocol. 4, 6