Treatment of Dorsal Avulsion Fracture at DIP Joint
For dorsal avulsion fractures at the DIP joint (mallet finger), strict continuous splinting of the DIP joint in full extension for 8 weeks is the primary treatment for uncomplicated injuries, with immediate surgical referral required for fracture-dislocations involving >30-40% of the articular surface or volar subluxation. 1, 2
Initial Assessment and Classification
Evaluate the fracture pattern to determine treatment pathway:
- Measure the size of the bony fragment - fragments involving >30-40% of the articular surface with volar subluxation of the distal phalanx require surgical fixation 2
- Assess joint alignment - dorsal subluxation or dislocation indicates a more severe injury requiring open reduction and internal fixation 3
- Obtain anteroposterior, lateral, and oblique radiographs to distinguish uncomplicated avulsion fractures from fracture-dislocations 1
Treatment Algorithm
For Uncomplicated Dorsal Avulsion Fractures (Simple Mallet Finger):
- Continuous splint immobilization in full extension for 8 weeks without interruption - this is critical as any flexion during the immobilization period restarts the healing timeline 1, 2
- The splint must maintain the DIP joint in extension while allowing PIP joint motion 1
- Begin active finger motion exercises of uninvolved joints immediately to prevent stiffness in adjacent joints 4
- Radiographic follow-up at approximately 3 weeks and at immobilization removal to confirm healing 4
For Fracture-Dislocations or Large Fragment Avulsions:
- Surgical open reduction and internal fixation is required when the bony fragment involves >30-40% of the articular surface or when there is volar subluxation of the distal phalanx 3, 2
- Fixation techniques include K-wire fixation or small screw fixation (1.5mm) depending on fragment size 5, 6
- Active exercise should begin 3-5 weeks postoperatively to prevent stiffness while allowing adequate healing 3
Critical Management Points and Common Pitfalls
- The 8-week splinting period must be strictly continuous - even brief interruptions for bathing or examination can compromise healing and require restarting the immobilization period 1, 2
- Avoid over-immobilization of uninvolved joints, as the American Academy of Orthopaedic Surgeons warns that excessive immobilization leads to stiffness requiring multiple therapy visits or additional surgical intervention 4
- Monitor for skin irritation and muscle atrophy, which occur in approximately 14.7% of immobilization cases 4
- Patients must understand that non-compliance with continuous splinting significantly worsens outcomes 2
Expected Outcomes and Follow-up
- Most acute mallet fingers treated with appropriate continuous splinting achieve satisfactory results, though some residual extensor lag may persist 2
- Surgically treated fracture-dislocations typically show somewhat limited range of motion (averaging 20 degrees in some series) but remain pain-free and functional 6, 3
- Long-term follow-up averaging 6.4 years shows no pain but persistent mild motion limitation in surgically treated cases 3