In this study, injection molding of three poly lactic acid (PLA) based bone screws was simulated and optimized through minimizing the shrinkage and warpage of the bone screws. The optimization was carried out by investigating the process factors such as coolant temperature, mold temperature, melt temperature, packing time, injection time, and packing pressure. A response surface methodology (RS...

BACKGROUND The aim of this study is to evaluate the various applications of cortical bone screws in oral and maxillofacial surgery. MATERIALS & METHODS The study was conducted in a teaching hospital located in, Bangalore, India, on 20 patients. These patients were categorized into three groups depending on the applications of these screws like, for achieving intermaxillary fixation in Group-1...

OBJECTIVES We aimed to further evaluate the biomechanical characteristics of two locking screws versus three standard bicortical screws in synthetic models of normal and osteoporotic bone. METHODS Synthetic tubular bone models representing normal bone density and osteoporotic bone density were used. Artificial fracture gaps of 1 cm were created in each specimen before fixation with one of two...

Internal lengthening nail (ILN) is a recent development in limb lengthening and deformity correction specialty. The ILN has the distinct advantage of combining acute deformity correction with gradual lengthening of bone. While using ILN, the short metaphyseal bone fragment may develop a deformity at the time of osteotomy and nail insertion or during bone lengthening because of the wide medullar...

PURPOSE To compare the compressive strength of cannulated versus non-cannulated cancellous screws for undisplaced femoral neck fractures in synthetic bones. METHODS 18 synthetic proximal femurs simulating an AO B1 valgus impacted femoral neck fracture in osteoporotic bone were used. The fracture angles were between 55º and 63º (Pauwels grade 2). Fixation was made using 6.5-mm non-cannulated s...

Rigid internal fixation with plates and screws is now standard for the treatment of fractures, osteotomies and reconstruction of the craniomaxillofacial skeleton. The latest innovations are self-drilling, self-tapping screws and locking miniplates. These screws offer the prospect of less instrumentation and faster application. Preclinical testing has shown them to be substantially more retentiv...

Aims Bone fracture fixation in orthopaedic surgery occurs with the use of implants, such as bone screws. Screws are tightened, typically manually, with the level of tightening depending on surgeons’ manual feel. However, this subjective insertion torque control can lead to overtighening and screw stripping 1 . Previously our group has shown that stripping torque can be predicted based on the to...

An experimental study of the fatigue life of cortical bone screws under conditions which stimulated in vivo usage was performed. The two most important factors influencing fatigue life were axial screw tension (the force normal of the plate to bone) and the cyclic shearing load. All screws failed at the root of the thread in the interface between the plate and the bone. A modified screw design ...

STUDY DESIGN Cadaveric biomechanical study. OBJECTIVE To determine fatigue behavior of cortical bone trajectory (CBT) pedicle screws. SUMMARY OF BACKGROUND DATA Cortical bone trajectory screws have been becoming popular in spine surgery; however, the long-term fatigue behavior of the new CBT screws remains understudied and limitations not well defined. METHODS Twelve vertebrae from six ca...