Cement augmentation of implantsno general cure in osteoporotic fracture treatment. A biomechanical study on non-displaced femoral neck fractures

摘要

Femoral neck fractures in the elderly are a common problem in orthopedics. Augmentation of screw fixation with bone cement can provide better stability of implants and lower the risk of secondary displacement. This study aimed to investigate whether cement augmentation of three cannulated screws in non-displaced femoral neck fractures could increase implant fixation. A femoral neck fracture was simulated in six paired human cadaveric femora and stabilized with three 7.3mm cannulated screws. Pairs were divided into two groups: conventional instrumentation versus additional cement augmentation of screw tips with 2ml TraumacemV+ each. Biomechanical testing was performed by applying cyclic axial load until failure. Failure cycles, axial head displacement, screw angle changes, telescoping and screw cut-out were evaluated. Failure (15mm actuator displacement) occurred in the augmented group at 12,500 cycles (+/- 2,480) compared to 15,625 cycles (+/- 4,215) in the non-augmented group (p=0.041). When comparing 3mm vertical displacement of the head no significant difference (p=0.72) was detected between the survival curves of the two groups. At 8,500 load-cycles (early onset failure) the augmented group demonstrated a change in screw angle of 2.85 degrees (+/- 0.84) compared to 1.15 degrees (+/- 0.93) in the non-augmented group (p=0.013). The results showed no biomechanical advantage with respect to secondary displacement following augmentation of three cannulated screws in a non-displaced femoral neck fracture. Consequently, the indication for cement augmentation to enhance implant anchorage in osteoporotic bone has to be considered carefully taking into account fracture type, implant selection and biomechanical surrounding. (c) 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:314-319, 2016.