Does Proximal Placement of the Syndesmotic Reduction Clamp Affect the Optimal Position for the Medial Tine? A Cadaveric Pilot Study

Abstract

Sagittal plane syndesmotic malreduction is associated with off-axis, eccentric reduction clamping and preferential placement of the medial tine anteriorly has been proposed to minimize the malreduction risk. Although clamp placement 1cm proximal to the plafond is recommend, no previous study has assessed whether differences in the anatomic position of the fibula within the incisura (eccentric 1cm superior and concentric 2 cm superior to the tibial plafond) affect the optimal position for the clamps medial tine during reduction of the syndesmosis. The purpose of the present cadaveric pilot study was to evaluate and compare the sagittal syndesmotic malreduction rate with various clamping vectors, 1cm and 2cm from the tibial plafond, respectively. Six through the knee cadaveric specimens were obtained. Kirschner wires and a surgical maker were used to denote placement of the reduction clamp laterally on the peroneal ridge of the fibula, and medially within the anterior, middle, and posterior thirds (Zones A, B, C) of tibia's width; 1 cm and 2 cm from the plafond. CT scans were obtained as controls, followed by destabilization of the syndesmosis. Reductions were then performed sequentially at each level (1 cm, 2 cm) and zone (A, B, C); and CT scans repeated for assessment. In most specimens (n = 5), an eccentric (1 cm) to concentric (2 cm) positional transition was observed within incisura fibularis. The transition altered the resulting fibular displacements in some specimens (2A anterior, vs 2B posterior), resulting in a higher malreduction rate with anterior (zone 2A, 33%) vs central (Zone 2B, 17%) positioning of medial tine. Although no definitive conclusions can be reached from the present pilot study, future studies with a greater number of specimens and clamping vectors are warranted to determine whether positional transitions of the fibula within the incisura fibularis affect the optimal position for the clamps medial tine.