ASTM F382 – Standard Specification and Test Method for Metallic Bone Plates
This specification and test methods are intended to provide a comprehensive reference for bone plates used in the surgical internal fixation of the skeletal system. The standard establishes consistent methods to classify and define the geometric and performance characteristics of bone plates.
Bone plates used in general orthopaedic surgery can be categorized into general types according to the following:
Cloverleaf Plate – A bone plate that has one three lobed end which contains screw holes.
Cobra Head Plate – A bone plate that has one flared triangular or trapezoidal end which contains multiple screw holes or slots, or both. This type of bone plate is often used for hip arthrodesis.
Reconstruction Plate – A bone plate that does not have a uniform width, but usually has a smaller cross-section between the screw holes or slots. The reduced cross-section between screw holes/slots facilitates contouring the bone plate in several planes. Reconstruction plates are often used in fractures of the pelvis and acetabulum.
Straight Plate – A bone plate with uniform width and a straight longitudinal axis. Straight plates are often used for fractures of the diaphyses of long bones.
Tubular Plate – A bone plate whose cross-section resembles a portion of a tube, and which has a constant thickness or a crescent section. Tubular plates are often used for fractures of the smaller long bones (that is, radius, ulna, and fibula).
Annex 1 – Single Cycle Bend Test
A bend test is used to determine values for the mechanical response of bone plates to a specific type of bending load. The information resulting from this test method can give the surgeon some insight into the mechanical response of a given bone plate. The bone plate is subjected to a single cycle four-point bending load. The bending stiffness, bending structural stiffness, and bending strength of the bone plate are then derived from the test record generated during the test and the testing configuration.
Annex 2 – Bending Fatigue Test
A bending fatigue test is performed to determine intrinsic, metallic bone plate structural properties. This test method may be used to determine the fatigue life at a specific or over a range of maximum bending moment levels, or to estimate the fatigue strength for a specified number of fatigue cycles of a bone plate. A bone plate is placed in a four-point bending fixture and oriented in such a way that the section of the bone plate that would normally bridge the fracture site is subjected to a uniform bending moment along the length of the section length. The bone plate is subjected to a constant frequency sinusoidal cyclic load waveform in four-point bending situation. The fatigue loading is continued until the specimen fails, a limit which is indicative of failure is reached, or the runout cycle count is reached.
Example of test results are shown below.