Functional outcomes of patients undergoing anterolateral versus anteromedial approaches of the ankle for pilon fractures

Pilon fractures of the distal tibia remain a treatment challenge to orthopedists. Careful preoperative planning is crucial to achieving desirable clinical outcomes, but currently the literature does not reach a consensus on which surgical approach is optimal. This study examines functional outcomes of two of the most common surgical approaches for pilon fractures, the traditional anteromedial approach and the more recently described anterolateral approach. The anterolateral approach is thought to produce better outcomes because of the greater amount of visualization into the articular surface and greater soft tissue coverage for the implant

The feasibility of a modified shoe for multi-segment foot motion analysis: a preliminary study

Background: The majority of multi-segment kinematic foot studies have been limited to barefoot conditions, because shod conditions have the potential for confounding surface-mounted markers. The aim of this study was to investigate whether a shoe modified with a webbed upper can accommodate multi-segment foot marker sets without compromising kinematic measurements under barefoot and shod conditions. Methods: Thirty participants (15 controls and 15 participants with midfoot pain) underwent gait analysis in two conditions; barefoot and wearing a shoe (shod) in a random order. The shod condition employed a modified shoe (rubber plimsoll) with a webbed upper, allowing skin mounted reflective markers to be visualised through slits in the webbed material. Three dimensional foot kinematics were captured using the Oxford multi-segment foot model whilst participants walked at a self-selected speed. Results: The foot pain group showed greater hindfoot eversion and less hindfoot dorsiflexion than controls in the barefoot condition and these differences were maintained when measured in the shod condition. Differences between the foot pain and control participants were also observed for walking speed in the barefoot and in the shod conditions. No significant differences between foot pain and control groups were demonstrated at the forefoot in either condition. Conclusions: Subtle differences between pain and control groups, which were found during barefoot walking are retained when wearing the modified shoe. The novel properties of the modified shoe offers a potential solution for the use of passive infrared based motion analysis for shod applications, for instance to investigate the kinematic effect of foot orthoses

Biomechanical evaluation of location and mode of failure in three screw fixations for a comminuted transforaminal sacral fracture model

Background: Pelvic ring–comminuted transforaminal sacral fracture injuries are rotationally and vertically unstable and have a high rate of failure. Objective: Our study purpose was to use three-dimensional (3D) optical tracking to detect onset location of bone–implant interface failure and measure the distances and angles between screws and line of applied force for correlation to strength of pelvic fracture fixation techniques. Methods: 3D relative motion across sacral–rami fractures and screws relative to bone was measured with an optical tracking system. Synthetic pelves were used. Comminuted transforaminal sacral–rami fractures were modelled. Each pelvis was stabilised by either (1) two iliosacral screws in S1, (2) one transsacral screw in S1 and one iliosacral screw in S1 and (3) one trans-alar screw in S1 and one iliosacral screw in S1; groups 4–6 consisted of fixation groups with addition of anterior inferior iliac pelvic external fixator. Eighteen-instrumented pelvic models with right ilium fixed simulate single-leg stance. Load was applied to centre of S1 superior endplate. Five cycles of torque was initially applied, sequentially increased until permanent deformation occurred. Five cycles of axial load compression was next applied, sequentially increased until permanent deformation occurred, followed by axial loading to catastrophic failure. A Student t test was used to determine significance (p < 0.05). Results: The model, protocol and 3D optical system have the ability to locate how sub-catastrophic failures initiate. Our results indicate failure of all screw-based constructs is due to localised bone failure (screw pull-in push-out at the ipsilateral ilium–screw interface, not in sacrum); thus, no difference was observed when not supplemented with external fixation. Conclusion: Inclusion of external fixation improved resistance only to torsional loading. Translational Potential of this Article: Patients with comminuted transforaminal sacral–ipsilateral rami fractures benefit from this fixation. Keywords: bone–implant failure, external fixator, fracture stabilisation, pelvic ring injury, pelvic screws, transforaminal sacral fractur

Biomechanical evaluation of location and mode of failure in three screw fixations for a comminuted transforaminal sacral fracture model

Background: Pelvic ringecomminuted transforaminal sacral fracture injuries are rotationally and vertically unstable and have a high rate of failure. Objective: Our study purpose was to use three-dimensional (3D) optical tracking to detect onset location of boneeimplant interface failure and measure the distances and angles between screws and line of applied force for correlation to strength of pelvic fracture fixation techniques. Methods: 3D relative motion across sacralerami fractures and screws relative to bone was measured with an optical tracking system. Synthetic pelves were used. Comminuted transforaminal sacralerami fractures were modelled. Each pelvis was stabilised by either (1) two iliosacral screws in S1, (2) one transsacral screw in S1 and one iliosacral screw in S1 and (3) one trans-alar screw in S1 and one iliosacral screw in S1; groups 4e6 consisted of fixation groups with addition of anterior inferior iliac pelvic external fixator. Eighteen-instrumented pelvic models with right ilium fixed simulate single-leg stance. Load was applied to centre of S1 superior endplate. Five cycles of torque was initially applied, sequentially increased until permanent deformation occurred. Five cycles of axial load compression was next applied, sequentially increased until permanent deformation occurred, followed by axial loading to catastrophic failure. A Student t test was used to determine significance (p < 0.05). Results: The model, protocol and 3D optical system have the ability to locate how subcatastrophic failures initiate. Our results indicate failure of all screw-based constructs is due to localised bone failure (screw pull-in push-out at the ipsilateral iliumescrew interface, not in sacrum); thus, no difference was observed when not supplemented with external fixation. Conclusion: Inclusion of external fixation improved resistance only to torsional loading. Translational Potential of this Article: Patients with comminuted transforaminal sacral eipsilateral rami fractures benefit from this fixation