Ebook Principles of deformity correction: Part 2
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Ebook Principles of deformity correction: Part 2
CMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2 translation, and length. Angulation and rotation are angular deformities, measured in degrees. Translation and length are displacement deformities, measured in distance units (e.g., millimeters, inches, etc.). In Chap. 9, we discussed how angulation (axis in the transverse [x-y] plane) and rotation Ebook Principles of deformity correction: Part 2 (axial [z] axis) deformities can be resolved threc-dimensionally and characterized by a single vector (ACA) inclined out of the transverse plane (chaEbook Principles of deformity correction: Part 2
racterized by x.y.z coordinates). Similarly, translation (displacement in the transverse plane) and length (displacement axially) can be combined intoCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2ly characterized by three projected angles (rotations) and three projected displacements (translations).Therefore, six deformity parameters are required to define a single bone deformity. Mathematically, it is necessary to assign positive and negative values to each rotation and each translation, de Ebook Principles of deformity correction: Part 2pending on the direction of rotation of each angle and the direction of displacement of each translation. The signs (+/-) of these angles and translatEbook Principles of deformity correction: Part 2
ions are determined by the mathematical convention of coordinate axes and the right-hand rule.The unique position of an object (bone segment) can be dCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2l axes and rotating about these same three axes. The final position after three orthogonal translations is independent of the order undertaken. The final position after three orthogonal rotations is dependent on the order or sequence undertaken (► Fig. 12-1).Stated more formally,rotation is not comm Ebook Principles of deformity correction: Part 2utative.Deformity analysis, as discussed in previous chapters, is conducted using AP and LAT view radiographs of the bone deformity. Considering thatEbook Principles of deformity correction: Part 2
a radiograph is an X-ray projection of objects onto a plane (section), the mathematical field concerning projection and section (the plane of observatCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2ilch • RoaFig. 12-1Although the order in which orthogonal translation is undertaken does not affect the final position of an object, the order in which an object is rotated about orthogonal axes affects its final spatial orientation. Three identical blocks are illustrated (frit column). Each of the Ebook Principles of deformity correction: Part 2blocks is shown as undergoing a 90° rotation in yaw (F). a 90“ rotation in pitch (P), and a 90“ rotation in roll (R), each in a different order. NoteEbook Principles of deformity correction: Part 2
the very different final orientations depending on the Order in which the rotations were undertaken. Rotation is not commutative.Gérard Desargues, a sCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2 theorem and published a text on conic sections and projective geometry in 1640. All printed copies of these works were lost. Fortunately, a student of Desargues, Philippe de la Hire, made a manuscript copy of Desargues’s book. Nearly 200 years later, this copy was found serendipitously in a booksho Ebook Principles of deformity correction: Part 2p by the geometer Michel Chasles (1793-1380). Along with other 19th century geometers, Chasles rediscovered and further developed projective geometry.Ebook Principles of deformity correction: Part 2
Chasles was the first to realize that the complex repositioning of an object in six axes (three translations plus three rotations) could be duplicatedCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2Axh Deformity AtMlpl>*ndConMt>Mtion of all the rotations (angulation and rotation deformities) and all the translations (translation and length deformities). The central axis of this revolute in Space is the same as the vector that resolves the three rotations in space. When rotation occurs in each Ebook Principles of deformity correction: Part 2reference axis, the revolute will be inclined to all three reference axes. The offset from the central axis (radius) of the revolute is dependent on tEbook Principles of deformity correction: Part 2
wo translations, and the pitch of the thread is dependent on the third translation.The Chasles axis can be developed as a vector, with direction and mCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2hird from clinical examination (axial rotation) or from CT analysis of rotation deformity.Ry treating the rotation or Chasles axis as a vector quantity, one is able to exactly locate this axis in any of eight octants. By invoking the right-hand rule, one can readily determine the direction of rotati Ebook Principles of deformity correction: Part 2on about this axis to recreate the deformity. In addition to recreating observed angulation and rotation with a Single oblique axis, chasles showed thEbook Principles of deformity correction: Part 2
at this same axis, if displaced from the center of the fragment, can also provide translation in two planes. If the fragment is allowed to progress alCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2 scope of this book, but a few conceptual examples are provided (►Fig. 12-2).I nJ U-ỈA-ICharacterizing anatomic terms in their mathematical equivalents leads to improved understanding. Choose the point of interest, or origin, as the zero position. Assuming you are working on yourself, anterior is po Ebook Principles of deformity correction: Part 2sitive, right is positive, and cepha-lad is positive. Positive rotation about each of the axes is shown. The fragment is shown in reduced position (a)Ebook Principles of deformity correction: Part 2
. It is then rotated about an oblique displaced axis and advanced along the same axis. The fragment is shown in 40“ and 2-cm increments (b-f).This spiCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2the real world to move objects precisely through space. Moving objects through space is a problem encountered in many practical situations outside of orthopaedics. One of the most elegant solutions was the flight simulator developed in the early 1950s using the Stewart platform (Beggs I960). This sa Ebook Principles of deformity correction: Part 2me mechanism is used in amusement park rides. The Stewart platform uses six struts of adjustable length to move an object in any direction in space. IEbook Principles of deformity correction: Part 2
t is not just coincidental that the number of struts required corresponds to the number of axes of correction. If only five struts are used, the SysteCMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2scopes and milling machines and has been used in industry for years. It has now been applied to orthopaedics to allow simultaneous six-axis deformity correction.CHAFHR 12 Sa-MnCMarmityAMlyw and Correction BO----SandartJ Scuts--Mini 60-75 mmX-snort 75-96 mrrSnort 9O’2$mm Mcđutn 115-178 mmLong 189-283 Ebook Principles of deformity correction: Part 2 mm-----Ft«r Fl Strut!----X-ahort 91-121 firSnort 115-15? nwtiMflOum 143-205 mmLong 195-311 nwThe Taylor spatial frame construct is always the same: sEbook Principles of deformity correction: Part 2
ix struts connected to every other tab on a full ring. The master tab is always on the proximal ring and faces anterior. Looking down on the proximal CMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation, Ebook Principles of deformity correction: Part 2It is important to remember that this assembly docs not change for either side of thebody or for proximal or distal reference frames. The anti-mas-ter tab is the empty distal tab between struts I and 2. This tab is a virtual tab in a distal two-thirds ring construct. The available components consist Ebook Principles of deformity correction: Part 2 of rings (full, half, and two-thirds), struts (Fast Fx (Smith St Nephew] and standard), foot plates, and butt plates.bTaylor spatial frame adjusted tEbook Principles of deformity correction: Part 2
o perform the same function as the adjacent Ilizarov construct:CMAFtn uCHSix-Axis Deformity Analysis and CorrectionIn previous chapters, we defined deformity components and divided them into angulation, rotation,Gọi ngay
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