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(BQ) Part 2 book “Principles of deformity correction” has contents: Six-Axis deformity analysis and correction, consequences of malalignment, malalignment due to ligamentous laxity of the knee, ankle and foot considerations, sagittal plane knee considerations,… and other contents.
1111 CHAPTER 12 Six-Axis Deformity Analysis and Correction In previous chapters, we defined deformity components and divided them into angulation, rotation, 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 (axial [z] axis) deformities can be resolved three-dimensionally and characterized by a single vector (ACA) inclined out of the transverse plane (characterized by x,y,z coordinates) Similarly, translation (displacement in the transverse plane) and length (displacement axially) can be combined into a single displacement vector inclined out of the transverse plane (characterized by x,y,z coordinates) Deformity between two bone segments can be fully 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, depending on the direction of rotation of each angle and the direction of displacement of each translation The signs (+I-) of these angles and translations are determined by the mathematical convention of coordinate axes and the right-hand rule The unique position of an object (bone segment) can be determined by locating three non-collinear points on that object One segment can be moved with respect to another by translating along three orthogonal 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 commutative Deformity analysis, as discussed in previous chapters, is conducted using AP and LAT view radiographs of the bone deformity Considering that a radiograph is an X-ray projection of objects onto a plane (section), the mathematical field concerning projection and section (the plane of observation) is called projective geometry (Klirre 1955) Projective geometry is the mathematical basis of interpreting radiographs of bone deformities Yaw - Pitch - Roll Fig.12-1 Although 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 (first column) Each of the blocks is shown as undergoing a 90° rotation in yaw (Y), a 90° rotation in pitch (P), and a 90° rotation in roll (R), each in a different order Note the very different final orientations depending on the order in which the rotations were undertaken Rotation is not commutative Gerard Desargues, a self-educated engineer, published the first known text on projective geometry in 1639 Blaise Pascal, a French mathematician and philosopher, added his 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 bookshop by the geometer Michel Chasles (1793-1880) Along with other 19th century geometers, Chasles rediscovered and further developed projective geometry Chasles was the first to realize that the complex repositioning of an object in six axes (three translationsplus three rotations) could be duplicated by rotation of a threaded nut along a threaded shaft, the revolute The path of the nut in space is a curvilinear axis of correc- IIEJI CHAPTER 12 · Six-AxisDeformi!J AnalysisandCorrection d tion 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 reference axis, the revolute will be inclined to all three reference axes The offset from the central axis (radius) of the revolute is dependent on two 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 magnitude The three contributions to the vector are based on three angles (rotations): two from radiographs (AP and LAT views of angulation) and the third from clinical examination (axial rotation) or from CT analysis of rotation deformity By 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 rotation about this axis to recreate the deformity In addition to recreating observed angulation and rotation with a single oblique axis, Chasles showed that 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 along the shaft as it rotates (like a nut on a threaded shaft), the third translation can be addressed The exact positioning of this shaft is beyond the scope of this book, but a few conceptual examples are provided ( Fig 12-2) Fig 12-2 a-f Characterizing anatomic terms in their mathematical equivalents Ieads to improved understanding Choose the point of interest, or origin, as the zero position Assuming you are working on yourself, anterior is positive, right is positive, and cephalad is positive Positiverotation ab out each of the axes is shown The fragment is shown in reduced position (a) It is then rotated ab out an oblique displaced axis and advanced along the same axis The fragment is shown in 40° and 2-cm increments (b-f) This spiral or revolute motion can reproduce ( or correct) a six-axis deformity The Taylor Spatial Frame Fixator lntroduction The Chasles axis can be applied to the real world to move objects precisely through space Moving objects through space isaproblern encountered in many practical situations outside of orthopaedics One of the most elegant solutions was the fiight simulator developed in the early 1950s using the Stewart platform (Beggs 1966) This same 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 It 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 system is unstable; when seven struts are used, the system is overly constrained The Stewart platform also is used for the precise movements oflarge telescopes 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 CHA PTE R 12 · Six-Axis Deformity Analysis and Correction 1111 Standard Struts Mini 60-75 mm X-short 75-96 mm Short 90-125 mm Medium 11 178 mm Long 169-283 mm Strut Fast Fx Struts X-short 91 - 121 mm Short 116 152 mm Medium 143-205 mm Long 195- 311 mm t Anti-master tab Fig 12·3 The Taylor spatial frame construct is always the same: six 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 ring,as ifto put the ring on one's leg, the numbered struts are attached through starting at the master tab in a counterclockwise configuration It is important to remember that this assembly does not change for either side of the body or for proximal or distal reference frames The anti-master tab is the empty distal tab between struts and This tab is a virtual tab in a distal two-thirds ring construct The available components consist of rings (full, half, and two-thirds), struts (Fast Fx [Smith & Nephew) and standard), foot plates, and butt plates b c Fig 12-3 Taylor spatial frame adjusted to perform the same function as the adjacent Ilizarov construct: a Translation b Axial rotation c Angulation d Angulation-translation IlD CHAPTER 12 • Six-Axis Deformity Analysis and Correction a Anteroposterior plane angulation d Anteroposterior plane translation (proximal reference) b Lateral plane angulation e Lateral plane translation (proximal reference) In Memphis, Tennessee, in 1994, J Charles and Harold S Taylor first applied the Stewart platform and the Chasles theorem to orthopaedics They modified the Ilizarov external fixation system by connecting six telescopic struts that are free to rotate at their connection points to the proximal and distal rings This external fixator is called the Taylor spatial frame In Germany, a similar modification to the Ilizarov device, called the hexapod, was developed (Seide et al 1999) By adjusting only the strut lengths, one ring can be repositioned with respect to the other Using a computerprogram that calculates the strut lengths relative to deformity parameters, the frame can be preconstructed to mirnie any deformity A two-ring construct can simulate a singlelevel deformity, and a three-ring construct with six struts between each pair of rings can be preconstructed for a two-level deformity Simple and complex deformities are treated with the same frame The same frame construct - two rings and six struts- can simulate various Ilizarov frame constructs (~ Figs 12-3 and 12-4) The multiple angles and translations of a particular deformity are addressed simultaneously by adjusting the lengths of the struts only The Taylor spatial frame c Axial plane angulation I Axial plane Iranslaiion Fig.12-Sa-f Six deformity parameters needed to fully define a dinical deformity a Anteroposterior plane angulation b Lateral plane angulation c Axial plane angulation d Anteroposterior plane translation e Lateral plane translation f Axial plane translation fixator is capable of correcting all aspects of a six-axis deformity simultaneously This external fixator is very streng The angled six-strut construct Ioads each strut axially without applying bending forces to the inclined struts If one Iooks at only the points of attachment of the struts to the ring, the shape is a triangle instead of a circle The entire structure, including the side triangles formed by the struts and the two end triangles, has the same shape as the crystal structure of a diamond (octahedron) Not surprisingly, this is a very streng construct When compared with the Ilizarov external fixator, the spatial frame was 1.1 tim es as axially stiff, was 2.0 tim es CHAPTER 12 · Six-Axis Deformity Analysis and Correction a AP view frame offset lllJI b Axial frame offset c LAT view frame offset d Rotary frame offset (30° external rotation) Anteroposterior Mastertab 30° to origin Fig 12-6a-d = Center of reference ring as stiff in bending, and had 2.3 tim es the torsional stiffness The computational accuracy of the computer program is 1/1,000,000 inch and 1/10,000° The real mechanical accuracy using manual adjustment of the struts for even a full six-axis deformity correction has been measured to within 0.7° and mm To treat a specific deformity with the spatial frame, one must determine the frame parameters, the deformity parameters, and the mounting parameters The frame parameters consist of the proximal and distal ring diameters along with the strut type, sizes, and lengths The deformity parameters consist of the radiographic and clinical measurements of the three rotations and three translations, defined relative to a point designated as the origin on the reference segment and its corresponding point on the corresponding segment We present an example of the six deformity parameters in terms of a tibial model ( , Fig 12-5): (1) coronal plane Four mounting parameters determine the position of the center of the reference ring in space with respect to the assigned origin a AP view frame offset b Axial frame offset c LAI view frame offset d Rotary frame offset (30" external rotation) angulation, varus or valgus; (2) sagittal plane angulation, procurvatum or recurvatum; (3) axial plane angulation, internal or external rotation; (4) anteroposterior plane translation, medial or lateral; (5) lateral plane translation, anterior or posterior; (6) axial plane translation, short or long Measure the deformity parameters by characterizing the fragment-to-fragment deformity This characterization is independent of the selected frame size, but the translational parameters are depen dent on how the frame is oriented to the fragments Ei ther the proximal or distal fragment can be designated as the reference fragment The origin may be conveniently chosen as any point along the reference frag- 1111 CHAPTER 12 · Six-Axis Deformi!J Analysisand Correction ment's axis, as long as its corresponding point can be identified or determined The CORA is a good choice for the origin in many cases Using the CORA as the origin is the marriage of the CORA method to the method of simultaneaus six-axis deformity correction The corresponding point lies along the axis of the moving fragment and is determined by various planning methods discussed later in the chapter The mounting parameters define the position of the reference ring (proximal or distal) in space with respect to the position of the origin In other words, the mounting parameters determine the position of the center of the reference ring in space to the position of the assigned origin Once the mounting parameters have been assigned, the frame orientation to the limb can be anticipated However, the frame usually is applied first and the mounting parameters subsequently determined Four measurements defining the relationship of the reference ring to the origin determine the mounting parameters The four mounting parameters are as follows: (1) anteroposterior frame offset, medial or lateral offset to the origin; (2) lateral frame offset, anterior or posterior offset of the center of the reference ring to the origin; (3) axial frame offset, proximal or distal offset of the reference ring to the origin; and (4) rotational frame offset, the degree of rotation between the master tab (proximal reference) or anti-master tab (distal reference) to the designated anteroposterior plane (usually patella forward) (~ Fig 12-6) The rotational offset is either external or internal With most applications, the intent is to place the frame in a neutral position with no rotational offset However, if rotational offset is present but not accounted for, a secondary deformity will be created during the initial correction For example, if a varus deformity is being corrected and the frame has been mounted with an internal rotational offset, a secondary recurvatum deformity will be created during the varus deformity correction This occurs because the frame is correcting the varus deformity not in the anteroposterior plane but in an oblique plane because of the rotational offset that has not been accounted for On the other hand, a rotational offset allows the freedom to mount a frame in a better position for soft tissue dearance or patient comfort An external rotational offset of 90° in a proximal femoral two-thirds ring allows clearance for the opposite thigh and perineal area This same construct with a distal reference will result in a 60° external rotational frame offset due to the position of the distal anti-master tab (~ Fig 12-7) rotational offset = goo / Distal reference imaginary anti-master tab External rotalienal offset = 60° _ _ oo Patella torward Fig 12-7 An external rotational offset of 90° in a proximal femoral twothirds ring allows clearance for soft tissues The same construct with a distal reference will result in a 60° external rotational frame offset due to the position of the distal (imaginary) antimaster tab The anti-master tab is imaginary in this construct because the distal ring is a two-thirds ring Modes of Correction Currently, three program modes of correction can be accomplished with the Taylor spatial frame: chronic deformity, residual deformity, and total residual deformity program modes However, since the advent of the Total Residual Program, the earlier Chronic and Residual Programs have been used less frequently and are becoming of academic interest only In this chapter, we focus only on the total residual deformity mode For the total residual deformity mode, the rings are applied independently of each other Ideally, to facilitate the planning, the reference ring should be applied perpendicular to the long axis of the reference bone seg- CHAPTER 12 · Six·Axis Deformity Analysis and Correction a IIfl b Axial frame offset =54 mm proximal to origin I AP view frame I offset = 10 mm : LATERAL to origin ment Nevertheless, the planning can compensate for nonorthogonal mountings After the two rings are applied, the six struts are connected to the rings and the osteotomy is performed at a chosen Ievel The deformity is defined for the computer by six deformity parameters: AP view angulation, LAT view angulation, axial view angulation (rotation), AP view translation, LAT view translation, and axial view translation (shortening or lengthening) The three angulations (rotations) can be measured independently of the orientation of the reference ring The three translations are dependent on the orientation of the reference ring For orthogonal mountings of the reference ring, the measurement of translation can be made perpendicular to the long axis of the bone for AP and LAT view translations and along the long axis of the bone for axial translations If the reference ring is nonorthogonal, the translations are measured according to a virtual grid of lines parallel and perpendicular to the reference ring The mounting parameters define the relationship of a chosen point on the reference axis (origin) to the center of the reference ring These mounting parameters include offset of the center of the reference ring from the origin in the anteroposterior and lateral planes, axial offset of the reference ring from the origin, and rotational offset of the reference ring to the anatomic or designated neutral rotation (usually patella forward) The position of the corresponding or moving ring is defined by entering the moving ring size and strut length data into the computer The moving ring does not need to be perpendicular to the long axis of the moving segment During surgery, the appropriate ring size (diameter) and type (full, two-thirds, foot, etc.) are chosen for the proximal and distal rings Six struts that can connect the two rings are attached between the two rings The ring size and type and the type and length of struts chosen represent the frame parameters Fig 12-Sa,b The mounting parameters are influenced by the orientation of the reference ring The orange dots represent the center of the reference ring The green dots represent the corresponding point a An orthogonal reference ring to the proximal hone axis allows for easy determination of the mounting parameters b A non-orthogonal reference ring tilts the virtual grid and significantly changes the AP frame offset To permit gradual correction of the deformity, the computer prepares a schedule of correction based on the rate of correction desired The desired rate of correction can be chosen arbitrarily or according to a predetermined rate at a chosen structure at risk (SAR) Orthogonal reference ring placement facilitates planning by making the mounting parameter reference lines parallel and perpendicular to the reference bone axis line As long as one is prepared to adjust the planning to a nonorthogonal position of the reference ring, no difference in the ability of the computer to calculate a deformity correction solution is encountered ( , Fig 12-8) The recent advent of digital planning software (Spatial CAD; Orthocrat Ltd., Tel Aviv, Israel) automatically takes the orientation of the reference ring into consideration, making planning with an orthogonal reference ring as simple as with a nonorthogonal reference ring We prefer placing the reference ring as orthogonal as possible for ease of non-digital planning This might, however, be a vestige of our bias based on extensive experience with the Ilizarov device, with which orthogonal ring placement is critical 1111 CHAPTER 12 · Six-Axis Deformity Analysis and Correction Planning Methods J Charles Taylor developed the origin-corresponding point method of planning (also called the fracture method) It permits characterization of the deformity and mounting parameters relative to two points in space: the origin and its corresponding point John E Herzenberg and Dror Paley simplified this method by relating it to the CORA, coincidentally and conveniently renaming these methods the CORAgin and CORAsponding point methods Shawn C Standard added the virtual hinge method of planning The most recent planning method developed by J Charles Taylor is termed the line of closest approach (LOCA) The LOCA is a method of determining the location of osteotomy that minimizes translation during the deformity correction The five methods of planning are as follows: ( 1) fracture method, (2) CORAgin method, {3) CORAsponding point method, {4) virtual hinge method, and (5) LOCA With the fracture method, the surgeon chooses both the origin and corresponding points as points on opposite sides of the fracture These designated points should represent congruent points of the opposing fractured fragments With the CORAgin method, the surgeon chooses the origin at the CORA and then finds the Fig.12-9 Fracture method: two corresponding points (CP) on opposite sides of the fracture (e g., at the ends of a recognizable spike and corresponding negative of the spike) are chosen as the origin and corresponding point corresponding point With the CORAsponding point method, the surgeon chooses the corresponding point first, at a CORA, and then finds the origin With the virtual hinge method, both the origin and corresponding points are located at a CORA, on the convex edge of the bone Fracture Method The fracture method brings two points in space (origin and corresponding point) to the same location This method can be likened to docking a mobile object to a stationary object in space The fracture method is the simplest method to learn Two corresponding points on opposite sides of the fracture (e.g., at the ends of a recognizable spike and corresponding negative of the spike) are chosen as the ori- CHAPTER 12 · Six-Axis Deformity Analysis and Correction LAT view frame offsei AP view frame offsei posterior to origin Master Iab oarotation = ß Axial frame offset Frame proximal to origin Rolary frame offsei - - - - - - - - - , Mastertab =30° rotation Fig.12-10 The mounting parameters are calculated by determining the position of the origin with respect to the center of the reference ring It is important to note that the mounting parameters are always measured as perpendicular distances from the reference ring gin and corresponding point (JII> Fig 12-9) The origin is defined as the point on the reference fragment, and the corresponding point is defined as the point on the moving segment The deformity parameters are determined by calculating the angulation in the coronal and sagittal planes (from the midaxillary lines of the fragments), by measuring the displacement or translation between the origin and corresponding points (in the anteroposterior, lateral, and axial planes), and by estimating the rotation deformity based on clinical examination The mounting parameters are calculated by determining the position of the origin with respect to the center of the reference ring (JII> Fig 12-10) Once these parameters are determined, the strut settings areentered into the Total Residual Program and the correction schedule is generated The new strut settings are gradually dialed into position and the fracture deformity reduced (JII> Fig 12-11) B CHAPTER 12 · Six·Axis Deformity Analysisand Correction Fig.12·11 Once all the deformity, frame, and mounting parameters are determined and entered into the Total Residual Program, the struts are dialed to the new settings and the fracture deformity is reduced An important clinical strategy is to leave the fracture shortened and aligned This reduces swelling, compartment pressures, and pain Acute reductions with distraction should be avoided The spatial frame schedule will provide gradual reduction that is weil tolerated by the patient CORAgin Method In Situations in which no acute fracture with identifiable bone ends that correspond to each other is present, the fracture method cannot be used Such deformities are called chronic deformities and include congenital, developmental, and posttraumatic residual (nonunion, malunion) deformities With the CORAgin method, the origin is chosen to be the CORA, and the corresponding point is determined by using locallength analysis or by adding extrinsic length data (e.g., limb length discrepancy data per radiograph; ~ Fig 12-12) Local length analysis is used when the desired correction is a pure neutral wedge This analysis permits calculation of the amount of shortening that is present because of the Fig.12·12 With the CORAgin method, the origin is assigned to the CORA CHAPTER 23 · TKR and Total Hip Replacement Associated with Malalignment Fig 23-17 a, b a Malunion of the femur with severe arthritis of the knee b This extra-articular deformity was corrected with intra-articular hone resection ing the Ievel and magnitude of correction, as may be needed with a one-stage correction In either case, it is essential to preoperatively plan and determine the levels of all the CO RAs and the complexity of the deformity and to template the knee to determine whether a Standard intraoperative correction will suffice or whether this willlead to too much bone over-resection to compensate for the deformity and to too much secondary deformity due to osteotomy rule Clearly, the only perfect correction of a deformity is one that follows osteotomy rule or In most cases, this means osteotomy rule 1, with correction of the deformity at the Ievel ofthe CORA (II>- Figs.23-15 through 23-17) Total Knee Arthroplasty after Failed HTO A significant number of patients undergoing proximal tibial osteotomy for MCOA will subsequently require TKR In approximately 80% of these cases, there will be no unusual difficulty and the knee replacement will be relatively straightforward Some patients will require special consideration because of expected difficulties that may arise during joint replacement It is preferable to identify these patients and the specific factors that must be considered to ensure the best possible results Even with this knowledge, several authors have reported less than optimal outcomes ofTKR after HTO, with failure rates ranging from 20%-36% at 5- to 7-year followup (Mont et al 1994a, 1994b; Katz et al 1987; Windsor et al 1988) Preoperative Assessment Clinical Factors that have been found to infl.uence the outcome of total knee arthroplasties after failed HTO include no relief of pain after osteotomy, multiple operations before osteotomy, peroneal nerve palsy, refl.ex sympathetic dystrophy, and history of workers' compensation These should all be looked for in any preoperative assessment In addition, other clinical factors that should be assessed include the location of previous incisions, range-of-motion considerations, collateral Iigament integrity, and rotational deformities Rotational deformities after HTO can be the most challenging problern to address during revision to TKR For example, if the distal fragment has healed in exter- CH APTE R 23 · TKR and Total Hip Replacement Associated with Malalignment nal rotation, this will effectively increase the Q-angle a This can be addressed at surgery in extreme cases with a tibial tuberde medialization procedure to allow for appropriate patellar tracking after total knee arthroplasty b Radiographie A radiographic evaluation can be used to ascertain several potential problems in performing total knee arthroplasty after failed HTO These include the presence of hardware that may obstruct the tibial component, a nonunion that may have to be handled as a secondary procedure before arthroplasty, avascular necrosis of the tibial fragment, patella baja, which will make exposure difficult and may necessitate quadricepsplasty or tibial tuberde elevation, and truncated lateral tibial metaphysis, which may make seating of the tibial prosthesis difficult Proximal Tibial Osteotomy-Related Problems forTKR Multiple malalignments may exist and should be analyzed from preoperative films As stated above, rotational deformities of the distal tibia can be detected dinically and radiographically In addition, varus or valgus deformities may need to be addressed in a manner different from that used for the usual arthritis-related deformities For example, with a valgus deformity secondary to osteoarthritis in the typical case, the deformity is shared by the tibial and femoral bones However, this same deformity after HTO will be found almost entirely in the tibia and may be compensated for by the varus deformity from the original MCOA for which the osteotomy was initially performed When templating preoperatively, the surgeon should note this deformity location and realize that after femoral cuts are made, the knee will be placed in more valgus, which the tibial cuts will have to further overcorrect The implications of these cuts should be made with preoperative templating, as previously discussed for extra-articular deformities With severe valgus deformities, an ancillary osteotomy below the tibial tuberde may have tobe performed at the time of knee arthroplasty or as part of a staged procedure Subperiosteal exposure of the proximal tibia may be more difficult because of scarring after the osteotomy procedure The exposure is often more difficult because of Iimitation of eversion of the patella from previous scarring and patella baja The patella baja is a result of the dosing wedge osteotomy proximal to the tibial tuberde decreasing the distance of the patellar tendon insertion to the tibial joint line (II>- Fig 23-18) A lateral retinacular release may be necessary, and if further JL JL PTl PTI Fig 23-18 a, b a Lateral closing wedge osteotomy, shortening the distance between the patellar tendon insertion (PTI) and the joint line (JL) after closing wedge HTO b The patellar tendon insertion moves proximally (Modified from Mont l994a.) difficulty is encountered, exposure using proximal quadricepsplasty or tibial tuberde osteotomy may become necessary Ligament imbalance may be encountered in these knees The surgeon should be prepared to perform ligament advances as necessary to avoid the use of a more constrained prosthesis in some cases A complex ligament reconstruction technique for these patients has been presented by Krackow and Holtgrewe (1990) They described a combination of posterior cruciate ligament and MCL advancement Bone malalignments need to be addressed as for any extra-articular deformity As previously mentioned, a tibial tuberde medialization procedure may be necessary to address more severe rotational deformities In more severe cases of extra-articular deformity, a second osteotomy may be necessary before total knee arthroplasty Alternatively, availability of stemmed tibial components and off-set stems has made one-stage osteotomy and joint replacement more feasible (111>- Fig 23-19) EI D11 CHAPTER 23 · TKRandTotal Hip ReplacementAssociated with Malalignment Fig 23-19 a, b a Failed valgus closing wedge osteotomy of the tibia with excessive overcorrection and valgus collapse of the lateral compartment b After TKR, the lower limb is well aligned Note the lateral positioning of the tibial component (Reproduced with permission [Mont et al 1994 a).) Proximal Femoral Deformities and Total Hip Arthroplasty The most common femoral deformity is increased anteversion Other conditions that require hip arthroplasty and have associated deformities include developmental dysplasia, juvenile rheumatoid arthritis, metabolic bone disease, iatrogenic conditions after osteotomy, and posttraumatic deformities ( , Fig 23-20) The major decision is whether to customize the femur or the prosthesis For example, in anteversion of developmental dysplasia of the hip, the proximal femur can be rotated as much as 80° ( , Fig 23-21) Because the medial-lateral dimensions of the femur are smaller than the anterior-posterior dimensions, fitting of a standard prosthesis becomes almost impossible with so much torsional deformity In addition, the abductor Iever arm becomes compromised because the greater trochanter is then rotated from lateral to posterior The excessive anteversion predisposes to impingement posteriorly from the prosthesis or greater trochanter, which can Iead to dislocation Some of these problems can be addressed by using a custom prosthesis, but a malrotated extremity with poor abductor mechanism mechanics would still remain Another solution is to use modular stems CHAPTER 23 · TKR and Total Hip Replacement Associated with Malalignment lo ,' - o Fig.23-21 Femur with marked anteversion shown after resection of the neck and head The greater trochanter (GT) is shown in an extreme posterior location, leading to hip abductor dysfunction due to loss of Iever arm (see Chap 22) The normal wider medial lateral dimensions are oriented anteroposteriorly, making insertion of a prosthesis difficult (Reprinted with permission [Wolff et al.l991).] Fig.23·20a,b a Excessive valgus and anteversion with degenerative disease of the hip after developmental dysplasia b Post-osteotomy valgus deformity with internal fixation (Cameron 1993) that allow for adjustment of anteversion independently of metaphyseal filling A good solution to this problern would be to perform a proximal femoral osteotomy before placing a standard hip replacement (Glassman et al 1987; Holtgrewe and Hungerford 1989) This solution is satisfactory because healing is rapid in the metaphyseal bone where the osteotomy is made, the proximal femoral dimensions are improved for insertion of a standard prosthesis, and the abductor lever arm is improved Holtgrewe and Hungerford (1989) advocated the use of corrective osteotomies when patients had greater than 45° of proximal femoral anteversion They reported excellent results in nine patients who were treated with associated femoral osteotomy at the time of primary or revision total hip replacement Thus, the advantages of an osteotomy are the lower cost due to no need of a custom prosthesis, the correction of the deformity in the hone, and intraoperative fiexibility The disadvantages include the obligatory Ionger healing time (3-4 months) and increased thigh pain until the bone is healed ( , Fig 23-22) BI CHAPTER 23 · TKRandTotal Hip ReplacementAssociated with Malalignment Fig 23-22 a, b a Dysplastic hip after osteotomy shows planned wedge resection derotation osteotomy b Total hip replacement with proximal femoral osteotomy stabilized by stem of prosthesis c After union of osteotomy Preoperative Planning Clinical Physical examination can determine the extent of fiexion contracture and other deformities This can help in the determination of whether ancillary muscle releases during surgery will be necessary Little has been written concerning the release of soft tissue contractures around the hip However, the release of soft tissue contractures around the hip is essential to prevent functional LLD (Longjohn and Dorr 1998; Ranawat and Rodriguez 1997) due to apparent rather than actual LLD This occurs even when leg lengths are actually equal because abduction contracture around the hip Ieads to pelvic obliquity and the patient has the sensation that the surgically treated hip is much longer This can correct on its own as the soft tissues gradually stretch from their contracted position, but these contractures can also persist permanently Therefore, it is preferable to perform the appropriate muscle releases intraoperatively when possible Soft tissue releases are usually necessary when hip contractures are greater than 20° in flexion, abduction, or external rotation Radiographie AP and cross-table LAT films can be useful to determine the amount of bone deformity Occasionally, computed tomographic scans can be used for precise measurement of the degree of anteversion and other deformities Computed tomography guided three-dimensional reconstruction can be used for complex deformities A model can be used to determine the appropriate osteotomy that would be necessary before cuts are made on the patient's bone In cases of angular deformities, preoperative templating should be performed to ascertain the amount of deformity and the wedge that needs to be removed for proper placement of the prosthesis The appearance of marked shortening of the hip should indicate that soft tissue releaseswill be necessary to restore length and to avoid postoperative contractures Up to approximately cm oflength can be gained at the time of surgery without undue risk Acute lengthening greater than that can lead to sciatic or peroneal nerve injury Shortening of a femur for limb length equalization should not be performed through the femoral neck if the normal joint tension is reduced for risk of dislocation CHAPTER 23 · TKR andlotal Hip Replacement Associated with Malalignment SoftTissue Balancing During surgery, limitation of range of motion once the components are in place may indicate the need for soft tissue release The hip should be able tobe fully extended If not, two structures may be tight: the anterior capsule and the iliopsoas tendon Capsular tissue is easily excised with careful hemostasis The iliopsoas tendon should be palpated and recessed if it is felt to be too tight The hip should also be able tobe adducted to approximately 30° If adduction is more limited than that, the iliotibial band should be palpated and, if tight, some degree of release is necessary This can be accomplished by pie crusting the iliotibial band until this structure is stretched out sufficiently to permit hip abduction Limitation of abduction should be treated by open rather than percutaneous release of the adductor musdes through a separate incision, if necessary Bone Deformity Correction Management of rotational deformity has already been discussed The goal should be 15° of femoral anteversion with restoration of hip abductor mechanics In mild deformities, standard stems can be used The greater trochanter may need tobe removed and repositioned laterally to optimize abductor musde function Other options for more severe deformities include modular stems that allow for anteversion adjustment independently of metaphyseal filling and custom implants For severe deformities, a subtrochanteric derotational osteotomy is easily performed by dialing the degree of correction necessary after the cut and then fixing this osteotomy depending on the integrity of the cortical hone with wires and/or plates (~ Fig 23-22) All femoral deformities need to be evaluated for the need for custom and/or modular stems versus osteotomizing the femur to allow for standard stem usage For patients with angular deformities, the osteotomy can be performed at the apex of the deformity, with the size of the wedge determined from preoperative templating The osteotomy can be stabilized with a long stem prosthesis References Asp JPL, Rand JA (1990) Peroneal nerve palsy aftertotal knee arthroplasty Clin Orthop 261:233-237 Cameron HU (1993) The 3- to 6-year results of a modular noncemented low-bending stiffness hip implant: a preliminary study J Arthroplasty 8:239-243 Engelbrecht E, Siegel A, Rottger J, Buchholz HW (1976) Statistics of total knee replacement: partial and total knee replacement, design St George: a review of a 4-year observation Clin Orthop 120:54-64 Paris PM, Herbst SA, Ritter MA, Keating EM (1992) The effect of preoperative knee deformity on the initial results of cruciate-retaining total knee arthroplasty J Arthroplasty 7:527-530 Glassman AH (1998) Complex primary femoral replacement In: Callaghan JJ, Rosenberg AG, Rubash HE (eds) The adult hip Philadelphia Lippincott-Raven Glassman AH, Engh CA, Bobyn JD ( 1987) Proximal femoral osteotomy as an adjunct in cementless revision total hip arthroplasty J Arthroplasty 2:47-63 Healy WL, Iorio R, Lemos DW (1998) Medial reconstruction during total knee arthroplasty for severe valgus deformities Clin Orthop 356:161-169 Herbert A, Paley D, Herzenberg JE (1996) Nerve injury as a complication oflimb lengthening Presented at the 6th Annual Meeting of ASAMI-North America, Atlanta, February Holtgrewe JL, Hungerford DS (1989) Primary and revision total hip replacement without cement and with associated femoral osteotomy J Bone Joint Surg Am 71:1487-1495 Hungerford DS (1995) Alignment in total knee replacement lnstr Course Lect 44:455-468 Karachalias T, Sarangi PP, Newman JH( 1994) Severe varus and valgus deformities treated by total knee arthroplasty J Bone Joint Surg Br 76:938-942 Katz MM, Hungerford DS, Krackow KA, Lennox DW (1987) Results of total knee arthroplasty after failed proximal tibial osteotomy for osteoarthritis J Bone Joint Surg Am 69:225233 Krackow KA (1990) The technique of total knee arthroplasty C V Mosby, St Louis Krackow KA, Holtgrewe JL (1990) Experience with a new technique for managing severely overcorrected valgus high tibial osteotomy at total knee arthroplasty Clin Orthop 258: 213-224 Krackow KA, Weiss AP (1990) Recurvatum deformity complicating performance of total knee arthroplasty: abrief note J Bone Joint Surg Am 72:268-271 Krackow KA, Jones MM, Teeny SM, Hungerford DS (1991) Primary total knee arthroplasty in patients with fixed valgus deformities Clin Orthop 273:9- 18 Krackow KA, Maar DC, Mont MA, Carroll C IV ( 1993) Surgical decompression for peroneal nerve palsy aftertotal knee arthroplasty Clin Orthop 292:223-228 Longjohn D,Dorr LD (1998) Soft tissue balance ofthe hip J Arthroplasty 13:97-100 Lu H, Mow CS, Lin J (1999) Total knee arthroplasty in the presence of severe Ilexion contracture: a report of 37 cases J Arthroplasty 14:775-780 Mont MA, Alexander N, Krackow KA, Hungerford DS(l994a) Total knee arthroplasty after failed high tibial osteotomy Orthop Clin North Am 25:515-525 D1 TotJI Mont MA,Antonaides S, Krackow KA, Hungerford DS (1994b) Total knee arthroplasty after failed high tibial osteotomy: a comparison with a matched group Clin Orthop 299:125130 Mont MA, Fairbank AC, Yammamoto V, Krackow KA, Hungerford DS (1995} Radiographie characterization of aseptically loosened cementless total knee replacement Clin Orthop 321:73-78 Mont MA, Dellon AL, Chen F, Hungerford MW, Krackow KA, Hungerford DS (1996} The operative treatment of peroneal nerve palsy J Bone Joint Surg Am 78:863-886 Ranawat CS, Rodriguez JA (1997} Functionalleg-length inequality following total hip arthroplasty J Arthroplasty 12: 359-364 Rose HA, Hood RW, Otis JC, Ranawat CS, Insall JN (1982) Peroneal-nerve palsy following total knee arthroplasty: a review of The Hospital for Special Surgery experience J Bone Joint Surg Am 64:347-351 Sculco TP (1997} Complex reconstructions in total knee arthroplasty: anterior and posterior soft-tissue contracture Am J Knee Surg 10:28-35 Teeny SM, Krackow KA, Hungerford DS, Jones M ( 1991) Primary total knee arthroplasty in patients with severe varus deformity: a comparison study Clin Orthop 273:19-31 Windsor RE, Insall JN, Vince KG (1988} Technical considerations of total knee arthroplasty after proximal tibial osteotomy J Bone Joint Surg Am 70:547-555 Wolff AM, Hungerford DS, Pepe CL (1991) The effect of extraarticular varus and valgus deformity on total knee arthroplasty Clin Orthop 271:35-51 Subject Index Page numbers in italic refers to illustrations abduction moment 720 ACA (angulation correction axis) 99 ACA-CORA 100 achondroplasia 378,451,452 acute angular correction 383 acute correction 269,297, 346, 365, 506,509 adduction moment 442, 720, 729 ad Iatus 195 aJCD (anatomic axis to joint center distance) 9, 10 aJCR (anatomic axis: joint center ratio) 10 aJED (anatomic axis to joint edge distance) 10 aJER (anatomic axis: joint edge ratio) 9,10 AMA (anatomic-mechanical angle) amniotic band syndrome 628 Amstutz 275, 696 anatomic axis: joint center ratio (aJCR) 10 anatomic axis: joint edge ratio (aJER) 9,10 anatomic axis line 1, 1-3,61, 62,63 anatomic axis planning 61,63 - femoral deformities 81,81-85,87, 88,90,92,94,96,97,169 - tibial deformities 74,74-76, 165 anatomic axis to joint center distance (aJCD) 9, 10 anatomic axis to joint edge distance (aJED) 10 anatomic-mechanical angle (AMA) Anderson 696, 709 angle - anatomic-mechanical - horizontal orientation for the proximal femur 13 - joint orientation - longitudinal 101 - malleolar mortise 632 - Q 243,244-246 - reference 61 - template 64, 169 - transverse 101 angular deformity 99, 705 angulation - apical direction 175 - deformity 145,215,256 - levelof 67,142,188,266 - magnitude of 175 - multiapical 67, 76, 83 - plane of 175 - uniapical 67, 76, 83 angulation correction axis (ACA) 99 angulation only osteotomy 99 angulation-rotation deformity 235, 252 angulation-translation (a-t) 195 - deformity 205 218,218 - in different planes 209,209, 222 - osteotomy 99,106,203,218,218, 297,300 - point 205 - in the sameplane 205,219 ankle 5, 16,40,51,571 - arthritis 585,587,601 - arthrodesis 587, 588, 590, 592, 593-595,599,607,686,722,744,745 - axis of rotation 252, 252, 572, 636 - ball and socket 619,620-622 - distraction 597, 603, 636, 640 - fusion 590,612,722 - malorientation 28,163,165 - subluxation 575, 596, 636, 637 ankle-foot orthosis 521,539,597 ankle forward radiograph 40,41,44 ankle fusion malunion 608, 611 ankylosis 686 anterior cruciate Iigament 451 anterior tibial artery 287 anterolateral bow 144, 705, 707 anterior superior iliac spine 269, 565 anti-master tab 413,416,416,429 apical direction - angulation 175 - graphs 178 apparatus - EBI 370 - Heidelberg fixator 371-375,380, 382-383 - hex-fix 314-316,320,323,324,336, 345,381 - Ilizarov fixator 120,121, 134,231, 232, 293, 341' 342, 346- 349, 351- 357, 360-367,370,386,390,413,414,417, 430,433,476,515,520-523,537,548, 556,560,593,594,601,608,613-617, 620,622,629,631 , 636-644,640,658, 661,663,669,785 - Orthofix fixator 339,340, 343,370, 376- 379 - Taylor spatial frame 412,413, 414-416,420,424,428-430,431,432, 433 apparent limb length discrepancy 269, 270, 735, 736 appendix 193, 193,194,713-715 approximation 199 arc-shaped osteotomy 112 artery 287 - anterior tibial 287 - femoral 280,281,287 - map 287 - posterior tibial 287 - profunda femoris 287 - superficial femoral 287 arthritis 600 - ankle 585,587,601 - degenerative 437 - juvenile rheumatoid 794 - osteoarthritis 451, 465, 479, 482, 488,504 - septic 693 - unicompartmental 502 arthrodesis - ankle 587,588,590, 592,593-595, 599,60~686,722,744,745 - hip 686 arthrodesis nonunion 607 arthrogryposis 521 arthrosis 437 assessment - clinical 235, 270, 272, 273 - limb length discrepancy 270, 272, 273 - radiographic 272, 273 a-t (angulation-translation) 195 axis line 1, 99 - anatomic 1, 1-3, 61 , 62,63 - distal anatomic 61, 62, 63, 101 - distal mechanical 61, 62, 63, 101 - mechanical 1, 8, 61, 62, 63 - middle 72, 142, 144, 148, 151 - proximal anatomic 61, 62, 63, 101 - proximal mechanical 61, 62, 63, 101 axis of correction of angulation 186, 186 ball and socket ankle 619,620-622 banana model 257-259,265 base oftriangle method 183 bipedal stance 454 biplanar angular deformity 175, 333 Blackburne-Peel - index 568 - measurement 569 blade plate 293 blocking screws 327, 336 Blount's disease 267, 45 1, 465, 468, 469, 474,515 Blumensaat's line 8, 16, 155,314,569 Bombelli 668 hone block 708 hone graft 474,475 - tricortical 475 - tricortical iliac crest 297 bowing deformity - anterolateral 144,705, 707 - posteromedial 145,705 bowleg deformity 326, 333 bump 581 calcaneal osteotomy 598,599 calcaneus deformity 743 cannulated drill technique 354, 666 capsular release 565, 603 cartilage loss 465, 467, 486 cavus deformity 630, 633 center of rotation of angulation (CORA) 61,64,101 - altered 142 - method 64, 76,291 - neutral wedge 107 - resolution 140-142, 145 - true 113,140,144 cerebral palsy 761, 768, 771-775 Chasles,Michel 411,412,414 - axis 412 - theorem 414 chondrolysis 737 chondromalacia 243,247, 538 chondro-metaphyseal dysplasia 333 chronic deformity 416,420,426 Chronic Program 416 clinical assessment 235,270,272,273 - limb length discrepancy 270, 272, 273 - rotation deformity 235 closing wedge osteotomy 99, 106, 107, 171-174,291 closing wedge point 106 clubfoot 617,623,626,719 collinearity 10 compensatory mechanism 596 compensatory motion 596 (table) computed tomography 238,239 computer-assisted design 429 concentric circles, rule of 365 condylar deficiency 19 congenital - femoral deficiency 651 - limb length discrepancy 702, 705, 713,714 - pseudarthrosis of the tibia 346, 434 - pterygium 518,519,536 constrained construct 321 construct - constrained 321 - rotation 365, 614 - translation 367 - unconstrained 321 CORA (center of rotation of angulation) 61,64,101 CORA method 64,76,291 CORAgin method 418,420,420,421, 421,422,424,426,428 CORAsponding point method 418, 422,423,424 correction - acute 269,297,346,365,506,509 - acute angular 383 - gradual 269,297,346,365,366,509 - order of 294, 383 - overcorrection 455, 456, 502, 623 - rateof 364,417,430 - six-axis 383, 411-436 corticotomy 390-393 counter-angulation 379 Coventry 457,480,480,482, 485 coxa valga 658, 735, 735 coxa vara 651, 671, 735, 735 crouch gait 768, 770, 771, 773, 774, 775 cylindrical osteotomy 112 •• • DAA (distal anatomic axis) 61, 62, 63, 101 deep peroneal nerve 282, 283 deficiency - condylar 19 - congenital femoral 651 deformity - angular 99, 705 - angulation 145,215,256 - angulation-rotation 235,252 - angulation-translation 205,218, 218 - biplanar angular 175, 333 - bowing 144,145,705,707 - bowleg 326, 333 - calcaneus 743 - cavus 630,633 - chronic 416,420,426 - dynamic varus 451,453,484,485, 731 - equinus 581,586,587,591,592,633, 637, 640, 739 - femoral 517 - femoral head 673,674-683 - femoral neck 673, 674-683 - fixed flexion 500, 502, 502, 509, 511-537,672,718,749,749,751 - frontal plane 19,181 - hyperextension 155, 156,499, 522, 538,718 - multiapical 97 - multilevel fracture 231 - oblique plane 175,199,208,208 - parameters 411,414,414,415,417, 419,421,422,426,427,430,433,434 - posttraumatic 585, 633, 723, 724 - procurvatum 515,517,526,582,718 - pronation 574, 724, 725 - recurvatum 155-156,538,541 582, 585,751,751 - rotation 235,497,498 - secondary translation 99, 112, 114, 371,372 - six-axis 411-436 - supination 574, 724, 725 - tibial 515,517,526,582,718 - torsional 42,239,240,243,244, 245, 250,497, 755 - translation 195, 195 - valgus 574,574,577,578,653, 732, 735 - varus 574,574,577,578,653,735 Dega osteotomy 651 degenerative arthritis 43 de Ia Hire, Philippe 411 derotation 243,247,248,249,249,252 derotation osteotomy 32 Desargues, Gerard 411 developmental - dysplasia of the hip 794, 795 - limb length discrepancy 269 digital planning software 417 disease - Blount's 267,451,465,468,469,474, 515 - Perthes 684, 684 - Trevor's 532 displacement 105 distal anatomic axis (DAA) 61, 62, 63, 101 distal anatomic axis line 61, 62, 63, 101 distal mechanical axis (DMA) 61, 62, 63, 101 distal mechanical axis line 61, 62, 63, 101 distraction - ankle 597,603,636 - growth plate 132, 133 - hip 662, 684 - knee 510,530 - physeal 132, 629, 631 - subtalar 597 DMA (distal mechanical axis) 61, 62, 63,101 dome osteotomy 99, 112, 112, I 13, 171-174,300 dorsifiexion 581, 602, 603, 743 dynamic varus deformity 451,453, 484,485,731 dysfunction - Iever arm 761,772,774 - posterior tibial tendon 627 dysplastic hip 660, 668, 796 EBI fixator 370 Ellis-van Creveld syndrome 465,468, 470, 476, 478 Ely test 563 epiphysiodesis 703 equinus 581, 586, 587, 591,592, 633, 637,640, 739 extension contracture - of quadriceps 295 - ofknee 563 extension osteotomy 503 external fixator 346, 349,352, 353 - circular 346, 351 - EBI 370 - Heidelberg 371-375,380,382-383 -hex-fix 314-316,320,323,324,336, 345,381 - Ilizarov 120,121,134,231,232, 293,341,342,346-349,351-357, 360-367,370,386,390,413,414,417, - frontal plane deformity 19 neck 673 nerve 282 retroversion 755 torsion 42, 239,240,243,244, 245, 250 fern ur - golf club 304 - procurvatum deformity 517 - recurvatum deformity 155-156, 541 FFD (fixed Ilexion deformity) 159,500,502,502,509,511-537,672, 718,749,749,751 fibular - hemimelia 577,616 - neck 248, 278, 282, 283 - malunion 632 - overgrowth 451 - transport 455 fixator - circular 346, 351 - EBI 370 - external 346, 349,352, 353 - Heidelberg 371-375,380,382-383 - hex-fix 314-316,320,323,324,336, 345,381 - Ilizarov 120,121,134,231,232, 293,341,342,346-349,351-357, 360-367,370,386,390,413,414,417, 430,433,476,515,520-523,53~548, 556, 560, 593, 594,601,608,613-617,620,622, 629,631,636-644,640,658,661, 663,669,785 - internal 307 - monolateral 326,328,370-372 - Orthofix 339,340,343,370,376-379 430,433,476,515,520-523,537,548, 556, 560, 593, 594,601,608,613-617,620,622, 629,631,636-644,640,658,661, 663,669,785 - monolateral 326,328,370-372 - Orthofix 339,340,343,370,376-379 - Taylor spatial frame 418, 420, 421, 421 - Taylor spatial frame 412,413, 414-416,420,424,428-430,431,432, 433 fixator-assisted nailing (FAN) 121, extrinsic - length 420, 422, 423, 427 - origin 422, 423, 424 672,718,749,749,751 - hip 651,672,751 - knee 159,509,511-537,718,749,749 fiat distal femoral condyles 531 fiattop talus 587,590-593,611, 122,124,134,150,311,317 fixator-assisted plating 301,301,302, 304-307 fixed Ilexion deformity (FFD) 159,500,502,502,509,511-53~651, 615-617 FAN (fixator-assisted nailing) 122,124,134,150,311,317 fascia 28 7, 566 fascia lata 45 1, 563, 566 femoral - anteversion 755 - artery 280,281,287 - deformity 517 - fracture 557 121, flexible Iever arm 761, 768, 770, 771 Ilexion contracture 479,502, 529 focal dome osteotomy 112, 112, 113, - rotationofthe 441,747,766 - stiff 594,627 - thigh-foot axis 262 formula 175, 179, 193, 199,252,257, 259,262,264,430,695,702-704,710, 713,714 fracture - femoral 557 - method 418,418,420 - multilevel 231 - physeal 520-522, 705 - reduction 228,303,437,446 - subcapital 673,681 - tibial 210, 447 frontal plane knee joint laxity 37 frustum 572, 572 Fujisawa point 480, 481, 482 fulcrum 38, 40,761, 762, 764, 773 fusion - ankle 590,612,722 - hip 752 - subtalar 42, 597, 619 gait 509, 717 - analysis 440, 441, 455, 730, 732 - crouch 768,770,771,773,774,775 - high steppage 740, 740 - Iurch 735 - Trendelenburg's 660, 668, 690, 728, 735 GAlTRite 741 genu valgum 451 genu varum 609, 723, 730 geometry 114 Gigli saw osteotomy 396-408,409 gluteus medius 647, 649, 735 golf club femur 304 goniometer 19 gradual correction 269,297, 346, 365, 366,509 graft (see hone graft) graphic method 175, 179, 179,262,351 graphic method error 183 graphs 178 - apical direction 178 - translation 196 greater trochanter transfer 64 7, 660, 663,665-667,669,769 ground reaction vector 484, 572, 573, 582,720,721,726,726,738 growth - arrest 132-134,252-255,295,451, 468,470-472,510,511,530,544,546, 577,580,631 298,300 foot 571 - ankle-foot orthosis 521,539,597 - clubfoot 617,623,626, 719 - lengthening 769 - plantigrade 594, 598 - rockerbottarn 627,742,742,745 - databases 701 inhibition 695 plate 7, 158,476,695 plate distraction 132, 133 remaining 703, 709, 775 half-pin placement 321 harnstring recession 524 Harding approach 647 Heidelberg fixator 371-375,380, 382-383 hemi-epiphysiodesis 708 hemiplateau elevation 473,476 Heuter-Volkmann law 453, 708 hexapod 414 hex-fix 314-316, 320, 323, 324, 336, 345,381 high steppage gait 740,740 high tibial osteotomy 112, 479,480 hinge 306,355,355-357 hip 8,12,40,53,647 - abduction contracture 269 - abductor 649 - adduction contracture 269 - adductor 647,648 - arthrodesis 686 - distraction 662, 684 - dysplastic 660, 668, 796 - fixed Ilexion deformity 651,672,751 - fusion 687, 752 - malorientation 28, 717 - rotation of the 753-755 - subluxation 684 - totalreplacement 686,689,690,777, 795 hip forward radiograph 40 hip-knee-ankle-foot orthosis 521 Homan retractor 485 horizontalline of the pelvis 686, 687 horizontal orientation angle for the proximal fern ur 13 hyperextension deformity 155,156, 499,522,538,718 hyperlordosis 751, 752 hypochondroplasia 451, 453 iliotibial band 735, 783 Ilizarov fixator 120,121,134,231,232, 293,341,342,346-349,351-357, 360-367,370,386,390,476,413,414, 417,430,433,515,520-523,537,548, 556, 560, 593,594, 601, 608, 613-617, 620,622,629,631,636-644,640,658, 661,663,669,785 imaging (see also radiographs) - computed tomography 238,239 - magnetic resonance imaging 14, 442, 469,476, 722 - orthoroentgenogram 269 - scanogram 271,274,276 - SCOUt film 271 - teleoroentgenogram 269 IMN (intramedullary nail) 1, 121, 124, 297,307,308-310,315-318,324,326, 330, 332, 334,336, 337,339-342, 344, 345,474 impingement 502, 502, 581, 582, 583,586,619,622,636,721,742, 742,782 (table), 794 inclination of saw blade 261,264 inclined - axis 259 - focal dome osteotomy 266, 298, 300 - osteotomy 261,263,264 inguinal tunnel 282 Insall - method 485 - ratio 568 Insali-Salvati measurement 569 interference screws 317 internal fixator 306, 307 intersection point 9, 10, 23, 61, 63, 66, 72,79,93,611,688,706,707 intra-articular exostosis 533 intra-articular osteochondroma 533 intramedullary nail (IMN) 1, 121,124, 297,307,308-310,315-318,324,326, 330,332,334,336, 337,339-342,344, 345,474 - antegrade 316,317 - ending point 307, 309 - fixator-assisted nailing 311,317 - lengtheningovernail 307,337,513, 541,567 - retrograde 311-315 - starting point 308, 310, 314 intramedullary rod (see intramedullary nail) Jakoband Murphy method 481 JLCA (joint line convergence angle) 9,10,485,486,487,489,490 joint line convergence angle (JLCA) 9,10,485,486,487,489,490 joint orientation angle joint orientation line joint reaction force 441, 731 Judet quadricepsplasty 563, 565 juvenile rheumatoid arthritis 794 juxta-articular hinge 363 knee 5,13,31,46,155,465 - distraction 510,530 - fixed Ilexion deformity 159,502, 509,511-53~718,749,749 - Ilexion-extension axis 33 - hyperextension deformity 155, 156, 499, 522, 718 - joint contracture 275,502,502,518, 530 - joint laxity 37 - malorientation 157 - stiff 521,566 - subluxation 26,156,156,451,464, 558-562 - total replacement 479,482, 483 - version 443 knee forward radiograph 31, 32,41, 46 K-wire 292,292,312 Langenskiöld 478 lateral - compartment osteoarthritis 335, 504,505,506 - malleolus 572, 572 - thrust 451,454 lateral collateralligament 451, 484, 496,497 - laxity 451,452,464,479,484,496, 497,731 - tightening 456,457-459,464 lengthening over nail (LON) 307,337, 513,541,567 length gain 276 lesser trochanter 656 Ievel - of angulation 67, 142, 188,266 - of center of rotation of angulation 485 - of translation 195 leverarm - dysfunction 761, 772, 774 - flexible 761, 768, 770,771 - malrotated 768,771,772 - short 768 Ievers 761, 762 Iigament 287 - anterior cruciate 451 - lateral collateral 451, 484, 496, 497 - medial collateral 444,451,473,473 - posterior cruciate 509, 538, 780, 782 (table ), 786, 793 - tightening 456,457-459, 460,462, 464,496 ligamentous laxity 451 limb length discrepancy (LLD) 269, 566,695 - apparent 269,270, 735, 736 - developmental 269 - knee Ilexion-extension axis 33 - prediction 695,702 (jormulae) - true 270 - types 695 line - axis 1, 99 - Blumensaat's 8, 16,155,314,569 - horizontal of pelvis 686, 687 - joint orientation - longitudinal bisector 101 - of closest approach 418,426 - s 421,421 Subject Index - Shenton's 685 - transverse bisector 10 - w 421,421 LLD (limb length discrepancy) 269, 566,695 locking screws 324, 336 LOCA (line of closest approach) 418, 426, 426, 427, 428 LON (lengthening over nail) 307,337, 513,541,567 longitudinal angle 10 I longitudinal bisector line 101 L shaped osteotomy 99,498, 559 Iurch gait 735 MAD (mechanical axis deviation) 10,10 magnetic resonance imaging 14, 442, 469,476, 722 magnitude - of angulation 175 - of translation 199, 203 malalignment 19,437,451,465,485 - consequences 437 - test 19, 157 malleolar mortise angle 632 mal-nonunion 340,342,430 malorientation - ankle 28, 163, 165 - hip 28,717 - knee 157 - test 28, 159, 163, 165 malrotated Iever arm 768,771,772 malunion 201,205,207,208,212,213, 215,21~219,221,223,233,298,420, 424,426,431,432,57~603,605,608 - ankle fusion 608,611 - fibular 632 Maquet - barre! vault 480 - osteotomy 112, 113,480 master tab 413,415,416,416,419,429 MCL (medial collateralligament) 444,451,473,473 mechanical axis deviation (MAD) 10,10 mechanical axis line 1, 61, 62, 63 mechanical axis of the lower limb 10,12 mechanical axis planning 61 - femoral deformities 76, 77-79, 85-87,91,93,95,97 - tibial deformities 64,65-73 mechanism - compensatory 596 - patellofemoral 750 - screw home 443 medial - compartment osteoarthritis 451,465,479,482,486-489,498,501, 503,504 - displacement osteotomy 627 - malleolus 269 - thrust 451,454 medial collateralligament (MCL) 444,451,473 - laxity 454,462,464,473,473,479 - tightening 460, 462, 464, 496 meningococcemia 517,575, 612,471 method - base of triangle 183 - CORA 64, 76,291 - CORAgin 418,420,420,421,421, 422,424,426,428 - CO RAsponding point 418, 422, 423, 424 - Coventry 457, 480, 482, 485 - fracture 418,418,420 - graphic 175,179,179,262,351 - Insall 485 - Jakoband Murphy 481 - multiplier 697,699-701 (tables), 710 - Oganesyan 639 - virtual hinge 418,424,425,425 - Yasui 372,376,379 middle axis line 72, 142, 144, 148, 151 Millis-Hall osteotomy 283 model - banana 257-259,265 - necktie 256, 256 modes of correction 416 moment - abduction 720 - adduction 442, 720, 729 - arm 451,582,729 - of inertia 763, 765 mono-compartment osteoarthritis 479 Morscher osteotomy 664 Mose circles 4, Moseley 696, 696 motion compensatory 596 mounting parameters 415,415, 416-420,422,423,425,429 multiapical - angulation 67, 76, 83 - deformities 97 - osteotomy 140 multilevel fracture deformities 231 multiple osteotomy solutions 142 multiplier method 697, 710 Murphy 492,495 Musdes 287 nailing (see fixator-assisted nailing) neck shaft angle (NSA) 12 necktie model 256, 256 nerve 282 - deep peroneal 282, 283 - femoral 282 llD - peroneal 279,281,282,282,284,285, 456, 504, 506 - posterior tibial 282,282, 286, 586 - sciatic 282, 282, 518 nerve entrapment 279, 281, 282,282, 284,285,581,786 neuromuscular 522,525, 526, 608, 690, 717,761 neurovascular structures 278 neutral wedge CORA 107 neutral wedge osteotomy 108,294 Nishio osteotomy 299,662, 670 nomenclature nonunion 137, 199, 210,229, 231, 342, 420,426,431,474,475,567,604,566 - arthrodesis 607 - mal-nonunion 340,342,430 NSA (neck shaft angle) 12 oblique plane - analysis 175,179-185 - angulation-translation, different planes 209,209,222 - angulation-translation, sameplane deformity 205,219 - deformity 175,208, 208 - translation 199, 199 octahedron 414 Oganesyan method 639 olecranonization of the patella 539 olive wires 358,358 opening wedge osteotomy 99, 106, 106, 171-174,297 order of correction 294, 383 orientation of plane 197 Orthocrat 417, 429 Orthofix fixator 122,339,340,343,370, 376-379,513,632 orthoroentgenogram 269 osteoarthritis 335,451, 465,479,482, 488,504 osteochondroma 281,509 - intra -articular 533 osteophyte 500, 502, 509 osteotome 113,313 osteotomy 99 - angulation only 99 - angulation-translation 99, 106,203, 218,218,297,300 - arc-shaped 112 - calcaneal 598, 599 - closingwedge 99,106,107,171-174, 291 - corticotomy 390-393 - Coventry 457, 480, 482, 485 - cylindrical 112 - Dega 651 - derotation 32 - dome 99,112,112,113,171-174,300 - extension 503 - focal dome 112, 112, 113,298,300 focal domedrill guide 312 Gigli saw 396-408, 409 helical dome 299 high tibial 112,479,480 inclined 261, 263, 264 inclined focal dome 266, 300 L shaped 99, 498, 559 Maquet, barre! vault 480 medial displacement 627 midfoot 586 Millis-Hall 283 Morscher 664 multiapical 140 multiple drill hole 300,341 multiple solutions 142 neutral wedge 108, 294 Nishio 299,662, 670 opening wedge 99, 106,106, - pelvic 273,283,651,652,660 pelvic support 689, 689 percutaneous 307,354 rotation 237,243, 283,497 Salter 283 single solutions 140 subtrochanteric 139 supramalleolar 579,581,585 translation 99, 202, 202 171-174,297 - u 611,615,616 -V 99,611,617 -Wagner 663 - W shaped 99 -z 276 osteotomy rule 102,103,118,124, 133,137,291,294,679 osteotomy rule 103,104, 121,133,134, 292,294,300,348,627,679,680,691 osteotomy rule 104, 104, 118, 292 osteotomy rules 102,114 overcorrection 455, 456, 502, 623 PAA (proximal anatomic axis) 61, 62, 63,101 parallactic homologues 429,430,433, 434,434,436 parallax 34 partial growth arrest 705 Pascal, Blaise 411 passenger unit 725, 727 patella - alta 568 - baja 566,568,567-569 - olecranonization of the 539 patella forward radiograph 42 patellar maltracking 243, 247, 479,497, 498 patellar tendon 464 patellectomy 784, 785 patellofemoral instability 246 patellofemoral mechanism 244, 24 7, 497,498 Pauwels 437 pedobarograph 588,589,723,724,748 pelvic osteotomy 273,283,651,652, 660 pelvic support osteotomy 689, 689 pelvic tilt 269, 738, 756 percentile groups 699 (tab/es), 700 (table ), 702, 704 percutaneous osteotomy 307, 354 perichondrium 532, 533 peroneal nerve 279,281, 282,282,284, 285,456,504,506 Perthes disease 671, 684, 684 Phemister hone block 708 physeal - distraction 132,629,631 - fracture 520-522, 705 pitch 411,411,412 placement - half-pin 358, 359 - wire 358,359 plane - of angulation 175 - reference 31 planning - anatomic axis 61,63 - mechanical axis 61,64 plantar fascia 579 plantar Ilexion 581,582,582, 755 plantigrade foot 594, 598 plate - blade 293 - fixation 300, 307 - growth 7, 158,476,695 - Puddu 119, 305, 306 - step 301, 302, 305, 306 plateau depression 479, 504 plating (see fixator-assisted plating) PMA (proximal mechanical axis) 61, 62, 63, 101 point - angulation-translation 205 - closing wedge 106 - ending 307, 309 - Fujisawa 480,481,482 - intersection 9, 10, 23, 61, 63, 66, 72, 79,93,611,688,706,707 - opening wedge 106 - reference 63 - starting 308, 310, 314 polio 512,513,527,541,743,750 posterior cruciate Iigament 509, 538, 780,782 (table), 786, 793 posterior tibial artery 287 posterior tibial nerve 282, 282, 286, 581,586 posterior tibial tendon dysfunction 580,627 posteromedial bow 145, 705 posttraumatic deformity 585, 633, 723, 724 preconstructed 414, 433 preconstruction 348,349-354 prediction of limb length discrepancy 695,702 (jormulae) primary restraint 462 Pritchett 714 profunda femoris artery 287 program - Chronic 416 - modes of correction 416 - Residual 416 - Total Residual 416,419,420,422 program modes of correction 416 projective geometry 411,433 pronation deformity 574, 724, 725 prosthetic wear 777 protractor 19 protrusio 735, 735 proximal anatomic axis (PAA) 61, 62, 63, 101 proximal anatomic axis line 61, 62, 63, 101 proximal mechanical axis line 61, 62, 63,101 proximal mechanical axis (PMA) 61, 62, 63,101 pseudarthrosis of the tibia 346, 434 pseudoachondroplasia 451, 462, 463, 534 pseudolaxity 494-496 pseudo-patella alta 482, 482 pseudo-patella baja 482,482,483,483 pseudo-subluxation 684 Puddu plate 119,305,306 Q angle 243, 244, 246 quadriceps - extension contracture 295 - fatigue 155, 509 - muscle 155, 243, 244, 512, 563, 566, 647,749,750,755 quadricepsplasty - Judet 563,565 - Thompson 563 - V-Y 563 radiographic assessment 272, 273 radiographs 31-59 - ankle forward 40, 41, 44 - anteroposterior ankle to include tibia 40,43 - anteroposterior hip to include femur 40,43 - anteroposterior knee to include femur 40,43 - anteroposterior knee to include tibia 40,43 - cross-table lateral of hip 53, 54,54 - cross-table lateral of proximal fern ur 53,55 - hip forward 40 - knee forward 31, 32, 41, 46 - lateral ankle to include tibia 50 - lateral foot to include tibia in simulated weight bearing 53, 53 - lateral foot standing to include tibia 52,604 - lateral hip to include femur 48, 50 - lateral knee to include femur 48, 49, 50 - lateral knee to include tibia 48, 49, 50 - long axial 42, 45 - long lateral 46, 48 - patella forward 42 - radiographic examination in one plane, deformity component in other plane 57-59 - Saltzman 46, 573 - single-leg standing 34 - stress, valgus and varus 37,38-40, 486,496 - stressed long axial 45, 605 - Sugioka 55, 56 - tangential 39, 58, 59 rate of correction 364, 417, 430 rectus femoris 563,565, 774, 774 reference - angle 61 - perspective 429, 430,433,434, 436 - plane 31 - point 63 Residual Program 416 revolute 411,412 rickets 147,150,152,153,451,452,455, 578,735 right-hand rule 411,412 rocker 582, 718, 748 rockerbottarn foot 627,742,742,745 rod, rodding (see intramedullary nail) roll 411,411 rotation - axis of 252,252, 572, 636 - construct 365, 614 - deformity 235 - hip 753-755 - foot 441,747,766 - osteotomy 237, 243, 283, 497 rule - concentric circles 365 - osteotomy rule 102, 103, 118, 124, 133,137,291,294,679 - osteotomy rule 103, 104, 121, 133, 134,292,294,300,348,627,679,680, 691 - osteotomy rule 104, 104, 118,292 - osteotomy rules 102, 114 - right-hand 411,412 - similar triangles 364, 365 - thumbs 358,361 Salter osteotomy 283 SAR (structure at risk) 346,417,430 saw 258,260,261,263,264,267,292, 292,293,294,297,300,305 scanogram 271,274,276 sciatic nerve 281, 282, 282, 518 SCOUt film 271 screw home mechanism 443 screws - blocking 327,336 - interference 317 - locking 324, 336 secondary length 373 secondary restraint 451 secondary translation deformity 99,112,114,371,372 septic arthritis 693 Shapiro 695, 695 Shenton's line 685 short lever arm 768 Silverskiöld test 630 similar triangles, rule of 364, 365 single-leg stance 454, 480, 484 single osteotomy solutions 140 six-axis 411-436 skeletal maturity 695,702, 713, 714 skin 288 slipped capital femoral epiphysis 673,674-680,682,683 Smillie knife 634, 636 soft tissue - balancing 448, 456, 780, 783, 786, 787,797 - release 524 - technique 453 spina bifida 518 stance - bipedal 454 - single-leg 454,480,484 - phase 717 - time 747 stapling 708 Steinmann pin 294, 354 step plate 301,302,305,306 Stewart platform 412,414 stiff foot 594, 627 stiff knee 521 Stracathro approach 647 Streeter's syndrome 144, 145, 628-630 stressed long axial view 45, 605 stretch injury 247,282,283,287, 346 structure at risk (SAR) 346,417,430 struts 412,413,414,415,417,419,420 subcapital fracture 673,681 subluxation - ankle 575, 596, 636, 637 - hip 684 - knee 26,156,156,451,464,558-562 subtalar - distraction 597 - fusion 42, 597,619 subtrochanteric osteotomy 340, 650, 656,660,662,664,669,683 superficial femoral artery 287 supination deformity 574, 724, 725 supramalleolar osteotomy 579, 581, 585 syndrome - amniotic band 628 - Ellis-van Creveld 465,468,470,476, 478 - Streeter's 144,145,628-630 - tarsal tunnel 283,581,592 tarsal tunnel syndrome 283,581,592 Taylor spatial frame 412,413,414-416, 420,424,428-430,431,432,433 teleoroentgenogram 269 template angle 64, 169 tendo Achillis lengthening 634 tendon lengthening 509, 636 tendons 287 tensor fascia lata 563 test - Ely 563 - malalignment 19, 157,485 - malorientation 28, 157, 159,163, 165 - Silverskiöld 630 - Thompson's 634 thigh-foot axis 262 Thompson quadricepsplasty 563 Thompson's test 634 three-dimensional reconstruction 660,796 thumbs, rule of 358,361 tibia - congenital pseudarthrosis 346, 434 - procurvatum deformity 515, 517, 526,582,718 - recurvatum deformity 582 tibial - deformity 515,517,526,582,718 - fracture 44 - frontal plane deformity 19,181 - malrotation 246, 443 - torsion 497, 755 - tuberde 118, 496,554, 558, 783 tibiofibular fixation 354 tibiotalar joint 596 TKR (total knee replacement) 479, 482,483 torsional deformity 42, 239,240, 243, 244,245,250,497,755 torsional profile 235 total hip replacement 686,689, 690, 777,795 total knee replacement (TKR) 479, 482,483 Total Residual Program 416,419,420, 422 transfer of greater trochanter 647,660, 663,665-667,669,769 translation 195 - additive 204 - compensatory 204 - construct 367 - deformity 195, 195 - graphs 196 - Ievel of 195 - magnitude of 199,203 - osteotomy 202 - planeof 195,195,197,205,208,215, 217, 228, 677 - residual 222, 223, 224, 224, 225, 369 - secondary 99,112,114,371,372 transverse angle 101 transverse hisector line 101 Trendelenhurg's gait 660, 668,690 Trevor's disease 532 tricortical hone graft 475 tricortical iliac crest hone graft 297 trigonometry 175,179 193,193,199, 260 tripod 725 trochanteric overgrowth 660, 665 true - angulation plane 175 - apex 72, 205 - center of rotation of angulation 113, 140,144 - limh length discrepancy 270 unconstrained construct 321 uniapical angulation 67, 76,83 unicompartmental arthritis 502 U osteotomy 611,615,616 valgus deformity 574,574,577,578, 653,732,735 varus deformity 574,574,577,578, 653,735 version angle of the femoral neck 239 vessels 287 virtual hinge method 418,424,425, 425 Vitallum staples 708 Vosteotomy 99,611,617 V-Y quadricepsplasty 563 W line 421,421 Wagner osteotomy 663 wire - K- 292,292,312 - olive 358,358, 359 - placement 358,359 Wolff's law 708 W shaped osteotomy 99 Yasui 372,376,379 yaw 411,4Ü Z osteotomy 276 ... Three clinical examples of the use of the spatial frame are shown in , Figs 12- 27 and 12- 28 CHAPTER 12 · Six·Axis Deformi!Y Analysis and Corrertion Fig 12 27 a-g e AP view of tibia with a pre-constructed... include offset of the center of the reference ring from the origin in the anteroposterior and lateral planes, axial offset of the reference ring from the origin, and rotational offset of the reference... 12- 12) Local length analysis is used when the desired correction is a pure neutral wedge This analysis permits calculation of the amount of shortening that is present because of the Fig. 12 12