Fracture reduction force

Keywords— fracture-reduction robot, safety, musculoskeletal model, fracture-reduction path, fracture-reduction force. 

The aim of this paper is to strengthen the safety of a robot assisted fracture-reduction system by introducing a musculoskeletal model, which can predict and manage the fracture-reduction force. The musculoskeletal modeling of the hip fracture is useful for increasing the safety of the robot assisted fracture reduction. This model simulates the forces and moments to each joint movement. Two following functions are expected with this simulation. 

The reduction force simulation has been developed and the application methods are devised. This method is common for muscle simulations, but there are few studies that apply it to fracture reduction. Advantages include the ability to find the gentle reduction path that minimizes the reduction force from among the reduction paths that are generated from the navigation system. In addition, fracture-reduction force of two difference paths can be simulated. 

Complications from these injuries are directly related to the severity of the deforming force. This dictates the fracture pattern, the degree of displacement and the associated soft tissue injuries. Age of the child and the rate and accuracy of the fracture reduction and stabilisation are also important factors. The radiographic signs of premature closure usually become apparent 6 months after the injury. 

An unexpected large reduction force can be detected during the fracture reduction by comparing the reduction force measured in real time with the simulated reduction force. 

Though there have been several studies about the modeling of the lower extremities [4,5], the application of this modeling to hip fracture reduction is not found. In this study, the musculoskeletal modeling method is introduced, and the model is applied to the hip fracture. Finally, the reduction force is simulated for two reduction paths. 

In this study, the active force are not considered on the assumption that relaxants that block transmission of nerve impulses to the muscles were given in high doses before the fracture reduction this means the active force is not developed. Therefore, the active term of Eq. (1) can be canceled and this can be reivritten by Eq. (2). 

T. Gosling, R. Westphal, J. Fauulstich et al. (2006) Forces and torques during fracture reduction Intraoperative measurements in the femur. J OtIIm Res, 24(3) 333-338... 

It is known that bone is a semi-brittle material and will experience fracture with forces greater than its ultimate strength. Based on the maximum amount of stress, the viscoelastic behavior of tibia showed a tendency to propagate the fracture lines and also higher stresses were reached compared to the isotropic and transversely isotropic property cases of tibia during the impact cycle. This indicates the dependency of a viscoelastic material to the time and also the strain rate, as expected. Also, the observed reduction in the maximum amount of stress after removing the impact load can be seen as a consequence of stress relaxation in tibia. The minimum stress was found to be when a transversely isotropic material property was considered for tibia. 

Fracture toughness, rate dependence, bending and tensile type specimens, force-based analysis and dynamic data reduction, engineering polymers. 

The objectives of this paper are (1) to compare force based and dynamic tests methods and data reduction schemes for both bending and tensile type fracture specimens, (2) to define the requirements and limitations for the applicability of FBA and DKC methods, and (3) to determine fracture toughness values of several engineering polymers over a wide range of loading rates (up to 7 decades). 

At even higher loading rates, for which no valid force-time signal for applying an FBA data reduction scheme can be recorded, the DKC-method may be used to determine dynamic fracture toughness values, Kj. This requires an adequate technique to measure the time-to-... 

Size reduction involves the decrease in size of a panicle or granule by fracturing the material using, generally, one of the four forces shear, compression, impact, and tension. Single or combination of forces being applied to the material affect the level of size reduction that will be achieved, but also the magnitude and duration of the applied force(s) will help determine the overall resultant panicle size distribution. 

Roll crushers are comprised of two counterrotating rolls. This actions draws material into a nip zone between the rolls, producing high compression forces that fracture the ore. Reduction ratios of only 4 1 are obtainable, with a low production of fines. 

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