Purpose The pedicle screw is a surgical device that has become widely used in spinal fixation and stabilization. Postsurgical complications such as screw loosening due to fatigue loading and screw breakage still need investigations. Clinical parameters such as the screw insertion type and depth, the bone density, and the patient degree of mobility greatly affect the mechanisms of the implant's failure/success. Methods The current finite element study focused on the prediction of the pedicle screw pullout strength under various conditions such as insertion type, insertion depth, bone quality, and loading mode. Results As depicted in this study, the preservation of the pedicle cortex as in the N1 insertion technique greatly enhances the pullout resistance. In addition, the higher the screw-anchoring depth, permitting to gear a maximum number of threads, the better the protection against premature breakouts of pedicle screws. Conclusions In agreement with experimental data, the type of insertion in which the first screw thread is placed immediately after the preserved pedicle cortex showed the best pullout resistance for both normal and osteoporotic bone.

No abstract

Application of gait biomechanics are numerous and versatile. One of these applications is to study the shape and deformity of feet. Such studies aid in the establishment of standards for foot-wear manufacturers. Thus, this is a preliminary study to create a classification of Saudi population as a first step towards setting a Saudi standard for foot wear. In this study 2 groups; male and female; consisting of 50 each were used. Bare-foot plantar pressure measurements were performed 5 times for each foot using Novel Emed-m platform. Foot index and hallux angle were obtained from these measurements and used to classify the foot shape and deformity, respectively. Results show that the majority of the population tested herein has standard and normal feet; with standard average of 77% for female and 80 for male and normal average of 88% for both male and female.

No abstract

No abstract