Mini-fragment fixation is equivalent to bicortical screw fixation for horizontal medial malleolus fractures

Adam M. Wegner, Philip R Wolinsky, Michael A. Robbins, Tanya C. Garcia, Derek F. Amanatullah

Research output: Contribution to journalArticle

Abstract

Horizontal fractures of the medial malleolus occur through application of valgus or abduction force through the ankle that creates a tension failure of the medial malleolus. The authors hypothesize that mini-fragment T-plates may offer improved fixation, but the optimal fixation construct for these fractures remains unclear. Forty synthetic distal tibiae with identical osteotomies were randomized into 4 fixation constructs: (1) two parallel unicortical cancellous screws; (2) two parallel bicortical cortical screws; (3) a contoured mini-fragment T-plate with 2 unicortical screws in the fragment and 2 bicortical screws in the shaft; and (4) a contoured mini-fragment T-plate with 2 bicortical screws in the fragment and 2 unicortical screws in the shaft. Specimens were subjected to offset axial tension loading on a servohydraulic testing system and tracked using high-resolution video. Failure was defined as 2 mm of articular displacement. Analysis of variance followed by a Tukey- Kramer post hoc test was used to assess for differences between groups, with significance defined as P<.05. The mean stiffness (±SD) values of both minifragment T-plate constructs (239±83 N/mm and 190±37 N/mm) and the bicortical screw construct (240±17 N/mm) were not statistically different. The mean stiffness values of both mini-fragment T-plate constructs and the bicortical screw construct were higher than that of a parallel unicortical screw construct (102±20 N/mm). Contoured T-plate constructs provide stiffer initial fixation than a unicortical cancellous screw construct. The T-plate is biomechanically equivalent to a bicortical screw construct, but may be superior in capturing small fragments of bone.

Original languageEnglish (US)
Pages (from-to)E395-E399
JournalOrthopedics
Volume41
Issue number3
DOIs
StatePublished - May 1 2018

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Ankle Fractures
Fracture Fixation
Weight-Bearing
Osteotomy
Tibia
Ankle
Analysis of Variance
Joints
Bone and Bones

ASJC Scopus subject areas

  • Surgery

Cite this

Mini-fragment fixation is equivalent to bicortical screw fixation for horizontal medial malleolus fractures. / Wegner, Adam M.; Wolinsky, Philip R; Robbins, Michael A.; Garcia, Tanya C.; Amanatullah, Derek F.

In: Orthopedics, Vol. 41, No. 3, 01.05.2018, p. E395-E399.

Research output: Contribution to journalArticle

Wegner, Adam M. ; Wolinsky, Philip R ; Robbins, Michael A. ; Garcia, Tanya C. ; Amanatullah, Derek F. / Mini-fragment fixation is equivalent to bicortical screw fixation for horizontal medial malleolus fractures. In: Orthopedics. 2018 ; Vol. 41, No. 3. pp. E395-E399.
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