1. Supplemental method for the reduction of Irreducible Mallet Finger Fractures by Two Extension Block Technique : Dorsal Counterforce Technique
Jung Eun Lee (1), Young Ho Lee (2), Jihyeung Kim (2),
Hyun Sik Gong (3), Goo Hyun Baek (2)
(1) Gil Medical Center, Gachon University School of Medicine, Incheon, South Korea;
(2) Seoul National University Hospital, Seoul, South Korea;
(3) Seoul National University Bundang Hospital, Gyeonggi-do, South Korea

2. Lee YH, Kim JY, Lee SK et al. 2009
Two block, 0.9 mm K-wires
To prevent the rotation of the fracture fragment
Trans articular fixation: more volar side

3. Backgrounds So, we introduce adjunctive method
Prevent proximal migration
But, cannot make sufficient compressive force against distal part of dorsal fracture fragment
-> Hard to control ‘Dorsal rotation’
So, we introduce adjunctive method

4. Material and Methods 95 patients by two surgeons in one center
( ~ )
41 males and 54 females
Mean age : 34.0 years(14 to 60 years)
Mean post-trauma days : 7 days(0 to 18 days)
Mean follow-up period : 31.6 month(12 to 90)

5. Material and Methods Inclusion criteria
Closed, displaced mallet fractures
Greater than 30% of the articular surface
Associated with DIP joint subluxation
Exclusion criteria
Over 6 weeks from injury
Comminuted or open fractures

6. Material and Methods
Excellent
full extension, full flexion, no pain, loss of extension between 0-10 degrees
Good
full flexion, no pain, loss of extension between degrees
Fair
any loss of flexion, no pain, loss of extension 25 degrees> 25
Poor
any loss of flexion, persistent pain
Outcome assessment: Crawford’s evaluation criteria (1984)

7. Surgical technique
CASE 1. 60/M, Ring finger

8. After two parallel block wires were inserted
The red arrow showing irreducible dorsal fragment and distal interphalangeal joint incongruence, due to rotation of the dorsal fragment in the sagittal plane

9. An additional K-wire was used to apply counterforce against the distal part of the dorsal fragment and control rotation in sagittal plane
The K-wire used for dorsal counterforce was pushed into the fragment for fixation.

10. A fourth K-wire was inserted from the volar side, across the DIJ, to maintain extension and reduction

11. CASE 2. 30/M, Long finger
irreducible dorsal fragment and distal interphalangeal joint incongruence, due to rotation of the dorsal fragment

12. An additional K-wire was used to apply counterforce against the distal part of the dorsal fragment and control rotation in sagittal plane

14. Results
Among 95 patients, 18 patients(18.9%) need ‘dorsal counterforce technique’
(2007 – 2015, 9 years)
Mean time to union
: 6.1 weeks(5 to 8 weeks)
Congruent joint surface in all cases
Mean active flexion of DIP joint
: 83.7 degree(79 to 88)
Mean extension loss : 0.4 degree(0 to 4)

15. Results Outcome : According to Crawford’s evaluation system
excellent in 13 patients (72.2%)
good in 3 patients (16.7%)
fair in 2 patients (11.1%)
No skin defects, necrosis, or wound complications occurred
No digit had a prominent dorsal bump or a recurrent mallet deformity.

16. Conclusions Residual dorsal rotation of the fragment
→ step-off of the articular surface and to
decrease contact area of fracture surface
→ need repetitive reduction and manipulation
Our additional method for reduction of dorsal fragment is simple but efficient
<Dorsal Counterforce Technique>