YY/T 0591-2011Implants for osteosynthesis - Metallic lockable intramedullary nails (English PDF)

3.1 Geometric terms

3.1.1 Closed section

A section perpendicular to the longitudinal axis of a solid or hollow interlocking intramedullary nail having a continuous outer wall.

Discussion. For the purpose of trial and insertion, the irregularity and asymmetry of the sagittal and coronal planes of the interlocking intramedullary nail should be expected. Use for description.

3.1.2 Curved curvature

Bending is machined based on size and position, mathematical description or other quantifiable description and tolerances.

Discussion. For the positioning during the trial and insertion, the curvature of the sagittal and coronal planes of the interlocking intramedullary nail should be given for the intended use. description.

3.1.3 Diameter

The diameter of the circumcircle that surrounds the section of the interlocking intramedullary nail when measured along the working length of the interlocking intramedullary nail. If the measured diameter is working along If the length is not constant, the measurement position should be indicated.

3.1.4 Length

The length of the straight line between the most distal and proximal ends of the interlocking intramedullary nail.

3.1.5 Open section

A section of the longitudinal axis of the hollow interlocking intramedullary nail having a discontinuity perpendicular to the outer wall.

Discussion. For the positioning during the trial and insertion, the curvature of the sagittal and coronal planes of the interlocking intramedullary nail should be given for the intended use. description.

3.1.6 Potential critical stress concentration

Factors expected to cause stress concentration, including changes in section modulus, material properties, discontinuities, or other characteristics, where the region High stresses are generated under expected normal load conditions.

3.1.7 Working length

The length of the uniform section of the interlocking intramedullary nail that fits the medullary cavity in the backbone region.

3.1.8 Tolerance

Describe the acceptable deviation of the nominal size of the interlocking intramedullary nail.

3.2 Mechanical properties/structure

3.2.8 Represents a variable that specifies the number of cycles

3.2.1 Flexibility compliance

According to the definition and measurement method of the static four-point bending test described in Appendix A, it is locked under a certain bending load in a prescribed plane. The reciprocal of the intramedullary nail stiffness.

3.2.2 Fatigue strength after N cycles

According to the definition and measurement method of the test, the interlocking intramedullary nail is given at a given load ratio and not less than N cycles of loading.

Maximum cyclic mechanical parameters (eg, load, bending moment, torque, stress, etc.) that damage or meet other failure criteria.

3.2.3 Failure strength

The mechanical parameters (eg, load, bending moment, torque, stress, etc.) of the failure criteria are met according to the definition and measurement method of the test. (See Note 1)

Note 1. There is currently no test standard for this type of interlocking intramedullary nail.

3.2.4 Yield strength

According to the definition and measurement method of the test, the mechanical parameters of residual deformation (for example, load, bending moment, torque, stress, etc.) begin to occur.

3.2.5 No-load motion

The relative motion between the interlocking intramedullary nail and the bone in the absence of elastic strain and no (or very small) load changes. (See Note 1)

3.2.6 Structural stiffness

The maximum slope of the elastic portion of the load-displacement curve line according to the definition and measurement method of the test.

Discussion. For the bending of the specified plane, this is defined and determined in the static four-point bending test, as described in Appendix A.

3.2.7 Ultimate strength

The maximum mechanical parameters (eg, load, bending moment, torque, stress, etc.) that the structure can withstand in accordance with the definition and method of testing.

4.3.1 Preferred positioning

4.3.1.1 Right-left

4.3.1.2 Sagittal plane - coronal plane

4.3.1.3 Proximal-distal

4.3.1.4 Universal selection or multiple selection

4.3.2 Preferred anatomical location

4.3.2.1 Specific bone

4.3.2.2 Far-near-middle

4.3.2.3 Universal selection or multiple selection

4.3.3 Limited use only for special procedures

4.3.3.1 Emergency treatment of fractures.

a) the specified type;

b) Specify the location.

4.3.3.2 Reconstruction steps

4.3.3.3 General selection or multiple selection

12.1 Mark

It shall comply with the provisions of Chapter 11 of YY/T 0640-2008 and the marking of the implant shall not affect its intended performance.

12.2 Tags

It shall comply with the provisions of Chapter 11 of YY/T 0640-2008 and meet the following requirements.

a) diameter of the interlocking intramedullary nail (3.1.3);

b) Length of the interlocking intramedullary nail (3.1.4).

12.3 User's Manual

It shall comply with the provisions of Chapter 11 of YY/T 0640-2008.

A.1 Scope

A.1.1 This test method specifies a static four-point bend for determining the inherent structural properties of interlocking intramedullary nails for surgical fixation of the skeletal system.

Curve test. This test method includes bending tests in various planes defined relative to the main anatomical plane. Its purpose is to measure and lock the marrow The inner nail design is related to the bending strength and bending stiffness of the material.

A.1.2 This test method specifically defines a uniform open or closed section working length along the length of the body (WL >= 10 × diameter)

(WL) a locking intramedullary nail that is applied to the full length of the femur, tibia, tibia, tibia or ulna. This test method does not apply to only It is used as an intramedullary anchor for fixing a part of the long bone or short bone (such as metacarpal, humerus, toe bone, etc.).

A.1.3 This test method is not suitable for determining the intrinsic properties of the interaction between a locked intramedullary nail and bone or other biological material.

A.1.4 This test method cannot be used because there is not enough knowledge to predict the use of interlocking intramedullary nails in individual patients.

The clinical performance level of the interlocking intramedullary nail in special cases.

A.1.5 This test method cannot be used as a quality assurance document. Therefore, the statistical sampling technique for the production of interlocking intramedullary nails is not described.

A.1.6 This standard may not apply to all types of interlocking intramedullary nails. Recommended from the specific interlocking intramedullary nail and its potential use Carefully consider the applicability of this standard. A.1.7 This standard adopts the International System of Units (SI).

A.1.8 This standard does not attempt to address all of the safety issues involved, even those related to their use.

It is the responsibility of the users of this standard to establish appropriate safety and health practices and to clarify the applicability of regulatory restrictions prior to application.

A.2 Terms and definitions

The following terms and definitions apply to this document.

A.2.1 Flexibility compliance Reciprocal of the stiffness of the interlocking intramedullary nail under a certain bending load in a defined plane (1/EIe. interlocking intramedullary nail, y/F. test system).

A.2.2 Bending moment

The bending moment of the failure criterion is achieved in accordance with the definition and measurement method of A.5.

Discussion. Failure can be defined as residual deformation, fracture or distortion.

A.2.3 Yielding moment

The bending moment of plastic deformation defined by the 0.2% strain migration method is used on the load-displacement curve.

A.2.4 Bending structure stiffness bendingstructuralstiffness Test according to A.5, calculate according to the description in A.4.1.8 (equivalent bending stiffness EIe of the tested area) and the resistance of the interlocking intramedullary nail Bending ability. The stiffness of the curved structure is the normative property of the section within the working length of the interlocking intramedullary nail, regardless of the length of the interlocking intramedullary nail.

A.2.5 Fixture/locked intramedullary nail flexibility

The combination of the clamp and the interlocking intramedullary nail measured when the loading point is collinear with the support point (eg A.6.2). This value depends on the interlocking intramedullary nail Positioning, load, load direction and support span.

A.2.6 Ultimate bending moment

The bending moment at the maximum or ultimate load measured on the load-displacement curve in accordance with A.5.

A.2.7 Test mode

It consists of a compression load cycle, a constant displacement rate, and a specified failure.

The test mode is a single cycle loading, and the distance from the nearest critical stress concentration (CSC) is at least the interlocking intramedullary nail.

Three times the diameter, unless otherwise specified or the CSC is a feature of a conventional cross section over the working length.

A.3 Classification

The types of tests included in this standard are as follows.

a) Measurement of the intrinsic structural mechanical properties of the interlocking intramedullary nail - intrinsic performance.

b) Measurement of elastic stiffness and elastic strength in a four-point bending of a single cycle.

c) Measurement of the elastic compliance of a single-cycle clamp/locked intramedullary nail.

A.4 Steps

A.4.1 Bending test of the inherent performance of working length (WL)

A.4.1.1 Determine the span according to the provisions of A.4.1.2 and A.4.1.3, and set the span, s, c and L not to exceed 1% of the specified value.

A.4.1.2 As shown in Figure A.1, a four-point bending test is performed under laboratory conditions, and the support span L between the two rollers used is 10cm~50cm, the span c between the loading points should not be greater than L/3. The loading point is also loaded using the roller and loads and supports the roller shaft The diameter should be between 1.0cm and 2.6cm. Select the span according to the method given in A.7.1. Figure A.1 Four-point bending test

A.4.1.3 The recommended loading and support spans below can reduce laboratory-to-labor differences. If the general requirements of A.7.1 can be met, Use the recommended long or short span whenever possible. Short span s=c=38mm L=114mm Long span s=c=76mm L=228mm

A.4.1.4 Apply the same load at each loading point using a constant displacement rate of no more than 1 mm/s (Figure A.1 and Figure A.2).

As shown, a separate loading method located in the middle of the load point is usually used. The relative deflection y between the support point and the loading point (inside and outside) is measured. Correct For interlocking intramedullary nails made with strain rate sensitive materials, the displacement rate at a given strain rate can be calculated using the following approximate calculation method. Estimate. yR=St1% and c=L-2s (A.1) Y1% =sL 2( )c/300( )D (A.2) =s3L-4( )s/300( )D =s3c 2( )s/300( )D In the formula. St --- expected strain rate;

Y1%---the deflection of the maximum strain 1% estimated value at the loading point of the interlocking intramedullary nail; s --- the span of the loading point and the nearest support point; c --- intermediate span; L --- total span (c 2s); D --- with the diameter of the interlocking intramedullary nail.

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