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

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

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

Material and Methods 95 patients by two surgeons in one center (2007.08 ~ 2015.08) 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)

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

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 10-25 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)

Surgical technique CASE 1. 60/M, Ring finger

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

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.

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

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

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

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)

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.

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>