Plating displaced proximal humeral fractures is associated with a high rate of screw perforation. Dynamization of the proximal screws might prevent these complications. The aim of this study was to develop and evaluate a new gliding screw concept for plating proximal humeral fractures biomechanically. Eight pairs of three-part humeral fractures were randomly assigned for pairwise instrumentation using either a prototype gliding plate or a standard PHILOS plate, and four pairs were fixed using the gliding plate with bone cement augmentation of its proximal screws. The specimens were cyclically tested under progressively increasing loading until perforation of a screw. Telescoping of a screw, varus tilting and screw migration were recorded using optical motion tracking.Aims
Methods
Osteosynthesis of anterior pubic ramus fractures using one large-diameter screw can be challenging in terms of both surgical procedure and fixation stability. Small-fragment screws have the advantage of following the pelvic cortex and being more flexible. The aim of the present study was to biomechanically compare retrograde intramedullary fixation of the superior pubic ramus using either one large- or two small-diameter screws. A total of 12 human cadaveric hemipelvises were analysed in a matched pair study design. Bone mineral density of the specimens was 68 mgHA/cm3 (standard deviation (Objectives
Materials and Methods
When inserting a lag-screw across an arthrodesis, stress is concentrated under the screw head risking asymmetrical force distribution and fracture of the cortical bone bridge. The IO FiX (Extremity Medical, NJ USA) is a new intraosseous device comprising an X-Post on one side of and parallel to the arthrodesis and a lag-screw inserted through the head of the X-Post which reinforces the cortical bone bridge. The X-Post behaves as an internal washer improving force distribution across the arthrodesis. Being intraosseous, near to the neutral axis of bend also means the device is fatigue-resistant and soft tissue irritation is reduced. The IO FiX has not been independently verified and therefore we analysed its performance in a human cadaveric ankle model. Our null hypothesis was there is no difference in force generation and contact area in an ankle arthrodesis when the IO FiX is compared with partially-threaded lag-screws. We used ten randomized cadaver ankles with a mean age of seventy-one years (44–84 years) prepared with flat arthrodesis cuts. A Tek-scan (Boston, USA) pressure transducer was used to measure force and contact area produced when the IO FiX was compared with a standard lag-screw and washer. The median average force in the IO FiX group was 3.95 kg and 2.35 kg in the lag-screw group ( Our results suggest the IO FiX improves force generation and contact area across the arthrodesis. With the theoretical advantages of reduced soft tissue irritation and a lower risk of fatigue failure, the IO FiX offers a significant advantage compared with traditional fixation techniques.
Posterior malleolar fractures are present in up to 44% of all ankle fractures. Those involving > 25% of the articular surface have a higher rate of posterior ankle instability which may predispose to post traumatic arthritis. The posterolateral approach to the distal tibia allows direct reduction and stabilization of the posterior malleolus and concomitant lateral malleolus fractures. An anatomical study was performed to establish the safe zone of proximal dissection to avoid injury to the peroneal vessels in this uncommon approach. 26 unpaired adult lower limbs were dissected using the posterolateral approach to the distal tibia as described by Tornetta et al. The peroneal artery was identified coursing through the intraosseous membrane on deep dissestion as the flexor hallucis longus muscle was reflected medially. The level of its bifurcation was also noted over the tibia. Perpendicular measurements were made from the tibial plafond to these variable anatomical locations.Introduction
Methods
Percutaneous plating of the distal tibia via a limited incision is an accepted technique of osteosynthesis for extra-articular and simple intra-articular distal tibia fractures. In this study we identify structures are risk during this approach. Thirteen unpaired adult lower limbs were used for this study. Thirteen, 16-hole synthes®LCP anterolateral distal tibial plates were percutaneously inserted according to the manufacturer instructions and confirmed by xray. Dissection was performed around the plate to examine the relation of nerves and soft tissue. The neurovascular bundle was under the plate in one case. Over the horizontal limb of the plate, typically the superficial peroneal nerve had a variable course over all four screw holes. The anterior tibial artery coursed over hole number 3 and the Extensor hallucis longistendon was positioned over hole 3 or 4. The Anterior tibialis tendon skirted hole 4 in 12 cases. Over the vertical limb of the plate, the neurovascular bundle coursed over holes, 5 to 7, the superficial peroneal nerve over holes 5 to 7.Method
Results
