Biomaterial Database

Guidelines for external fixation frame rigidity and stresses. 1986

R Huiskes, and E Y Chao

Using results from FEM analyses and experiments as references, analytical methods are applied to develop simple approximate formulas to relate frame rigidity, maximal pin stresses, and peak pin-bone stresses in external fracture fixation (EFF) configurations in axial loading to the most important frame, pin, and bone parameters. It is found that, in a realistic range, the parameters can be adapted to vary the frame rigidity from about 13 N/mm to 17,000 N/mm, thereby reducing the maximal stresses in the pins and at the pin-bone interface by a factor of 140. In particular, when compromises have to be established in the frame characteristics in order to ensure a flexible configuration and limit the stress values at the same time, the formulas presented can provide useful guidelines. The side-bar separation and the pin modulus, in particular, can be adapted to decrease the rigidity, while only moderately increasing the stresses, thereby reducing changes for pin failure, pin-bone loosening, and pin-tract infection. A nomogram is presented for a quick reference to estimated relations between frame characteristics, rigidity, and stresses. It is believed that this material may be of use in EFF design and applications in clinical and animal experimental trials.

UI	MeSH Term	Description	Entries
D008433	Mathematics	The deductive study of shape, quantity, and dependence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Mathematic
D008962	Models, Theoretical	Theoretical representations that simulate the behavior or activity of systems, processes, or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Experimental Model,Experimental Models,Mathematical Model,Model, Experimental,Models (Theoretical),Models, Experimental,Models, Theoretic,Theoretical Study,Mathematical Models,Model (Theoretical),Model, Mathematical,Model, Theoretical,Models, Mathematical,Studies, Theoretical,Study, Theoretical,Theoretical Model,Theoretical Models,Theoretical Studies
D009984	Orthopedic Fixation Devices	Devices which are used in the treatment of orthopedic injuries and diseases.	Device, Orthopedic Fixation,Devices, Orthopedic Fixation,Fixation Device, Orthopedic,Fixation Devices, Orthopedic,Orthopedic Fixation Device
D001842	Bone and Bones	A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principal cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.	Bone Tissue,Bone and Bone,Bone,Bones,Bones and Bone,Bones and Bone Tissue,Bony Apophyses,Bony Apophysis,Condyle,Apophyses, Bony,Apophysis, Bony,Bone Tissues,Condyles,Tissue, Bone,Tissues, Bone
D001858	Bone Nails	Rods of bone, metal, or other material used for fixation of the fragments or ends of fractured bones.	Bone Pins,Bone Nail,Bone Pin,Nail, Bone,Nails, Bone,Pin, Bone,Pins, Bone
D004867	Equipment Design	Methods and patterns of fabricating machines and related hardware.	Design, Equipment,Device Design,Medical Device Design,Design, Medical Device,Designs, Medical Device,Device Design, Medical,Device Designs, Medical,Medical Device Designs,Design, Device,Designs, Device,Designs, Equipment,Device Designs,Equipment Designs
D005593	Fracture Fixation, Internal	The use of internal devices (metal plates, nails, rods, etc.) to hold the position of a fracture in proper alignment.	Osteosynthesis, Fracture,Fixation, Internal Fracture,Fixations, Internal Fracture,Fracture Fixations, Internal,Fracture Osteosyntheses,Fracture Osteosynthesis,Internal Fracture Fixation,Internal Fracture Fixations,Osteosyntheses, Fracture
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001696	Biomechanical Phenomena	The properties, processes, and behavior of biological systems under the action of mechanical forces.	Biomechanics,Kinematics,Biomechanic Phenomena,Mechanobiological Phenomena,Biomechanic,Biomechanic Phenomenas,Phenomena, Biomechanic,Phenomena, Biomechanical,Phenomena, Mechanobiological,Phenomenas, Biomechanic
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical