Introduction. Posterolateral tibial plateau fractures account for 7 % of all proximal tibial fractures. Their fixation often requires posterolateral buttress plating. Approaches for the posterolateral corner are not extensile beyond the perforation of the anterior tibial artery through the interosseous membrane. This study aims to provide accurate data about the inferior limit of dissection by providing measurements of the anterior tibial artery from the lateral joint line as it pierces the interosseous membrane. Materials and Methods. Forty unpaired adult lower limbs cadavers were used. The posterolateral approach to the proximal tibia was performed as described by Frosch et al. Perpendicular measurements were made from the posterior limit of the articular surface of the lateral tibial plateau and fibula head to the perforation of the anterior tibial artery through the interosseous membrane. Results. The anterior tibial artery coursed through the interosseous membrane at 46.3 +/− 9.0 mm (range 27–62 mm) distal to the lateral tibial plateau and 35.7 +/− 9.0 mm (range 17–50 mm) distal to the fibula head. There was no significant difference between right or left sided knees. Discussion. This cadaveric study demonstrates the safe zone (min 27 mm, mean 45mm) up to which distal exposure can be performed for fracture manipulation and safe application of a buttress plate for displaced posterorlateral tibial plateau fractures. Evidence demonstrates quality of reduction correlates with clinical outcome and the surgeon can expect to be able to use a small fragment buttress plate of up to 45mm as this is the mean

The Interosseous Membrane (IOM) of the forearm is made up of ligaments, which are involved in load balancing of the radioulnar joint and the shaft. Motion models of the forearm are necessary for planning orthopedic surgeries, such as osteotomies, which aim at solving limit of the range of motion or instabilities. However, existing models focus on a pure kinematic approach, omitting the physical properties of the ligaments, thus limiting the range of application by missing dynamical effects. We developed a model that takes into account the mechanical properties of the IOM. We simulated the pro-supination by creating an elastic coupling to the desired motion around the standard axis of rotation. We tested our model on a healthy subject, using CT-reconstructed bone models, and literature data for the ligaments. Multiple parameters, including forces of ligaments and positions of landmarks, are output for analysis. The length of the ligaments over pro-supination was in agreement with the literature. Their rest lengths must be recorded in future anatomical studies. The IOM helps in maintaining the contact with cartilage, except in late pronation. Scarring of the central band increases the force generated along the axis of rotation toward the wrist, while scarring of the proximal part does the opposite in pronation. In contrast to kinematic models, the proposed model is helpful to study the effect of physical properties of the IOM, such scarring, on the forearm motion. Future work will be to apply our model to pathological cases, and to compare to clinical observations

Purpose. The anterior inferior tibiofibular ligament (AiTFL) is the primary lateral ligamentous stabilizer of the ankle syndesmosis. Current syndesmosis repair techniques traverse the tibia and fibula, but do not anatomically reconstruct the AiTFL. We compared a novel AiTFL anatomic repair technique (ART) to rigid syndesmosis screw fixation (SCREW). Method. Twelve cadaveric below knee specimens were compared radiographically and using a biomechanical testing protocol. All specimens underwent a CT scan of the ankle joint prior to testing. Next, the AiTFL, interosseous membrane and deltoid ligament were sectioned, and the posterior malleolus osteotomized, to recreate a trimalleolar-equivalent ankle fracture. The posterior malleolus was repaired with the posterior ligamentous insertions intact and functional (PMALL). Ankles were examined under fluoroscopy with an external rotation stress exam and the medial clear space (MCS) measured. Specimens were then randomized to receive either a conventional syndesmosis screw (SCREW), or the novel anatomic repair technique (ART). External rotation stress fluoroscopy was repeated. A second CT was completed and the fibular position compared to the pre-injury CT. Each specimen was then loaded in external rotation until failure using a custom biomechanical jig. Results. The MCS during stress examination increased by 1.04 0.31mm in the PMALL group. MCS increased significantly less at only 0.300.07mm (p=0.002) in the ART group. The SCREW fixation method demonstrated a delta MCS of 0.280.16mm (p=0.008). Post repair CT showed that 33% of specimens were subluxed from the SCREW group compared to 0% for the ART. Mean torque at failure for ART was 24.85.5Nm compared to 16.85.8Nm for SCREW (p=0.01). Conclusion. Repair of the posterior malleolus alone demonstrated a greater than 1mm of medial clear space widening and is not sufficient to re-establish syndesmotic stability. Addition of the ART or SCREW technique restored syndesmotic stability. None of the ART specimens demonstrated fibular subluxation, while 33% of SCREW specimens were subluxed anteriorly on CT. Biomechanical strength of the ART was found to be greater than that of rigid screw fixation