Inserting a screw into a long bone introduces a stress riser that can predispose the bone to fracture. Where multiple screws are inserted this vulnerability may be increased. It is thought that the pattern of screw insertion plays an important part in determining the susceptibility of the bone to stress fracture. In order to study the importance of pattern of screw insertion, third generation c...

The aim of this study was to compare the interfragmentary compression generated across a simulated femoral fracture model by a conventional 4.5 mm AO/ASIF cortical lag screw with a differentially pitched cortical compression screw. A 45-degree osteotomy was made in a whole bone composite femoral shaft, this was internally fixed with either a conventional 4.5 mm AO/ASIF cortical lag screw or the...

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...

BACKGROUND The primary stability of cancellous screw is difficult to obtain in bone of compromised quality and failure of screw fixation is common. To overcome this problem, it is proposed to locally deliver bisphosphonate from the screw. An in vivo validation of the increase in fixation of the cancellous screw is then needed in compromised bone. METHODS In this study, we used an overdrilling...

It is a huge stress that remaining screws in the bone cannot be seen from the bone surface to remove the screw with fluoroscopy. Sometimes 2D fluoroscopy technique is difficult to remove hidden screws or metal pieces. To seek the hidden screw, skin incision, cortical bone loss and weakness of the long bone shaft will be increased. No case of total hip arthroplasty with screw removing assisted o...

BACKGROUND Bone cement augmentation is commonly used to improve the fixation stability of orthopaedic implants in osteoporotic bone. The aim of this study was to evaluate the effect of novel bone cements on the stability of bone screw fixation by biomechanical testing and to compare them with a conventional Simplex(®)P bone cement and requirements of the standards. METHODS Basic biomechanical...

BACKGROUND: Ludloff osteotomy fixation with compression screws has been widely used in the treatment of Hallux Valgus deformities [1, 2]. Generally six weeks of non-weight-bearing is required postoperatively to allow bone union. Besides the significant inconvenience due to non-weight-bearing, noncompliance may induce malunion, nonunion and loss of correction, indicating screw fixation is not st...

Fixation with a dynamic hip screw (DHS) is one of the most common methods for stabilizing intertrochanteric fractures, except for unstable and reverse oblique fracture types. However, failure is often observed in osteoporotic patients whereby the lag screw effectively 'cuts out' through the weak bone. Novel anti-migration blades have been developed to be used in combination with a lag screw ('B...

The fundamental problem in osteoporotic fracture treatment is significant decrease in bone mass and bone tissue density resulting in decreased firmness and elasticity of osteoporotic bone. Application of standard implants and standard surgical techniques in osteoporotic bone fracture treatment makes it almost impossible to achieve stable osteosynthesis sufficient for early mobility, verticaliza...

INTRODUCTION Pedicle screw fixation in a severely osteoporotic spine remains a challenge for orthopaedic surgeons. Previous studies have demonstrated that pedicle screw fixation is highly correlated to the bone mineral density [1], and increasing the screw’s pullout strength can be achieved using a variety of methods, these include the use of pedicle screws with various designs [2,3]. However, ...