Femoral neck fractures are a large clinical and economical problem. One of the most common fixation options for femoral neck fractures are multiple cancellous screws. A previous clinical study has shown the lack of washers to be the single largest predictor of fixation failure in the treatment of femoral neck fractures with cancellous screws. This finding was somewhat surprising as washers do not prevent the screws from backing out and do not provide any increase resistance to varus collapse. Therefore a follow-up biomechanical study was designed to test this observation. The purpose was to evaluate the maximal insertional torque of screws in osteoporotic bone with and without washers. We hypothesized that the lateral cortex of an osteoporotic proximal femur does not provide sufficient counter resistance for the screw heads to obtain maximum torque upon screw insertion in the femoral head and that the use of washers would increase screw purchase by providing a larger rigid surface area and subsequent higher counter resistance thereby allowing a higher maximal screw insertion torque. We used eight matched pairs of osteoporotic fresh-frozen human cadaveric femurs (age >70 years, all female). Two screws each were inserted in each femur either with or without a washer and maximal insertional torque was measured using a 50 Nm torque transducer. The testing was performed using a customized device which allowed the torque transducer to apply a constant axial force and torque speed to the screws. A paired Student's t-test was used to compare the maximal screw insertional torque of screws with washers versus screws without washers in matched pairs.Introduction
Methods
The most common treatment options for fixation of osteoporotic distal femur fractures are retrograde nails and locking plates. There are proponents of more elastic titanium plates as well as more rigid steel plates; No clear superiority of one over the other has been established. We aimed to evaluate the mechanical differences between stainless steel and titanium locking plates in the fixation of distal femur fractures in osteoporotic bone. We hypothesized that due to its higher elasticity titanium locking plates can absorb more energy and are therefore less likely to “cut” into the bone compared to stainless steel locking plates resulting in improved metaphyseal osteoporotic fracture fixation. We used eight matched pairs of osteoporotic fresh-frozen human cadaveric femurs (age >70 years, all female). Within each pair we randomized one femur to be fitted with a Less Invasive Stabilization System (LISS-Titanium locking plate) and one with a Distal Locking Condylar Plate (DLCP-Stainless steel locking plate). A fracture model simulating an AO 33-A3 fracture was created (extraarticular comminuted fracture) and specimens were subsequently subjected to step-wise cyclic axial loading to failure. We used an advanced three dimensional tracking system (Polhemus Fastrak) to monitor the movement of the distal fragment relative to the real time distal plate position allowing us to evaluate distal implant cut-out.Introduction
Methods
1) to examine the reporting of outcome measures in orthopaedic trials, 2) to determine the feasibility of blinding in published orthopaedic trials and 3) to examine the association between the magnitude of treatment differences and methodological safeguards such as blinding. Specifically, we focused on an association between blinding of outcome assessment and the size of the reported treatment effect; in other words: does blinding of outcome assessors matter?
1) the outcome measures used and 2) the use of a methodological safeguard: blinding. We calculated the magnitude of treatment effect of blinded compared to un-blinded outcome assessors.
1) studies labelled as Level I have high reporting quality and 2) Level I studies have better reporting quality than Level II studies. One should address methodological safeguards individually.
1) younger age, particularly age between 36 and 45 years, 2) experience of less than 10 years, 3) having a PhD degree, and 4) working in an academic or teaching setting. The majority of the respondents (65%) were aware of the Journal’s evidence-based medicine section, and 20% used the Journal’s evidence-based medicine abstracts in clinical decision-making. This increased awareness in evidence-based medicine was also reflected in a frequent use of Cochrane reviews in clinical decision-making (27%). Surgeons who used the Journal’s evidence-based medicine abstracts and Cochrane reviews had significantly higher competence scores.