BACKGROUND Understanding of implant failure mechanisms is important in the successful utilization of anterior cervical plates. Many variables influence screw purchase, including the quality of the bone. The purpose of this study was to assess the relationship of screw pullout and screw insertional torque across a wide range of bone mineral densities (BMDs). METHODS A total of 54 cervical vert...

STUDY DESIGN Axial pullout tests using fresh cadaveric thoracolumbar vertebral bodies. OBJECTIVES To evaluate the effect of a new injectable calcium phosphate cement on the axial pullout strength of both revised and augmented pedicle screws in comparison with polymethyl methacrylate and in terms of injection method. SUMMARY OF BACKGROUND DATA Failure of pedicle screws by loosening and back ...

BACKGROUND Pedicle screw pullout due to poor bone quality, mainly caused by osteoporosis, is a common problem in spine surgery. Special implants and techniques, especially PMMA augmentation, were developed to improve the fixation of pedicle screws. PMMA injection into a pilot hole or through a screw involves the same risks as vertebroplasty or kyphoplasty, regardless of the technique used. Espe...

The purpose of this study is to evaluate the biomechanical properties of stainless steel and bioabsorbable screw fixation of the clavicle to the base of the coracoid. Seven matched pairs of fresh frozen shoulders were prepared by removing all soft tissue except the acromioclavicular and coracoclavicular ligament complexes. The shoulders were randomly selected and fixed with 4.5-mm stainless ste...

The geogrid-reinforced soil structures play important roles in the reinforcement applications since 1980s. Generally in design of the geogrid-reinforced soil structures, the soil-geogrid interaction behavior is not directly considered. Instead, the interaction strength is represented by the consolidation drained strength of soil commonly. However, neglecting the effect of compaction and suction...

The pullout strength of a collagen bone anchor that creates interference fixation as the result of radial swelling on hydration was compared with a Mitek rotator cuff anchor after insertion into the greater tuberosity of human cadaver humeri. Bones were fully hydrated at 37 degrees C. Stiffness, peak load, and the mode of failure were recorded. Real and apparent bone densities were measured. Pe...

BACKGROUND The pullout strength of pedicle screws is influenced by many factors, including diameter of the screws, implant design, and augmentation with bone cement such as PMMA. In the present study, the pullout strength of an innovative fenestrated screw augmented with PMMA was investigated and was compared to unaugmented fenestrated, standard and dual outer diameter screw. METHODS Twenty f...

Twenty-seven paired human cadaveric knee specimens were used to determine the effect of surgical technique and various interference screw parameters on the pullout strength of patellar tendon femoral bone blocks. The study compared the fixation strength of endoscopically inserted and conventional "rear-entry" screws of different diameters and lengths. In all tests the most frequent mode of fail...

Pedicle screws are the main fixation devices for certain surgeries. Pedicle screw loosening is a common problem especially for osteoporotic incidents. Cannulated screws with cement augmentation are widely used for that kind of cases. Dual lead dual cored pedicle screw has already given promising pullout values without augmentation. This study concentrates on the usage of dual lead dual core wit...

Study Design Biomechanical analysis of lateral mass screw pullout strength. Objective We compare the pullout strength of our bone cement-revised lateral mass screw with the standard lateral mass screw. Methods In cadaveric cervical spines, we simulated lateral mass screw "cutouts" unilaterally from C3 to C7. We salvaged fixation in the cutout side with polymethyl methacrylate (PMMA) or Cortoss ...