Acute scaphoid fractures are commonly fixed with headless cannulated screws positioned in the center of the proximal fragment.
BACKGROUND: An increasingly popular ankle fusion method uses plates and screws positioned on the anterior aspect of the tibiotalar joint.
Patients in this study with screws positioned posteriorly still achieved good outcome, suggesting that a screw that deviates from the centre of the tunnel gives satisfactory graft fixation.
They hypothesized that two 5 mm diameter pedicle screws positioned at a 10° to 15° angle from each other within the same pedicle would perform better than a single 6 mm screw would alone.
An intraoperative image intensifier was used to control the angular stable screw position in the humeral head in true AP and transaxial view to avoid intraarticular screw positioning.
In some cases a mean fluoroscopy time of up to 18 minutes was needed for iliosacral and transiliacal screw positioning [ 22].
Cut-out was defined as being primary when the reason for this failure was of biomechanical origin, i.e. it was determined by fracture geometry before and after fracture reduction and by the lag screw positioning.
This study has identified three variables associated with high risk of cut-out: unstable fracture type (basicervical and complex fractures), non-anatomical reduction and non-optimal lag screw positioning.
The tensioning tests consisted of a micrometer screw, positioned at the center of the rear part of the canvas, used to impose horizontal displacements to the center of the canvas.
We secured the bone transport segment with a 1.5-mm transport wire by threading the wire through a 3.5-mm cannulated screw, positioned perpendicular to the long axis of the bone (Fig. 2).
