PERSONAL BONE CUTTING MEASUREMENT PLANNING SOFTWARE AND DISTAL FEMORAL OSTEOTOMY BONE CUTTING AND SCREW GUIDE
Technical Field
The invention relates to the cutting-measurement navigation system, which processes webbased radiological screenshots used in the field of Orthopedic Surgery in the medical sector to detect the curvature in the bone for the correction cut to the bone (Osteotomy) in the plate method of Varus and Valgus deformities in the knee joint (DFO: Distal Femoral Osteotomy), to a 3D modeling program such as SolidWorks, where the values measured by this navigation are transferred to a three-dimensional printer and custom designed osteotomy and external plate screw guide.
State of the Art
Nowadays, the procedures are measured manually through X-rays and the bone is cut and corrected manually with the help of wire and markers during surgery in the treatment of varus and valgus deformities in the knee joint. Currently, the nearest technology is the France-based httDs://newcliptechnics.com/contact/ NewClip company's single-use Osteotomy guide Activmotion. In addition, there is no separate planning software for each patient in this company's technology, and the guide is produced with a normal injection mold suppression system. Even though this company makes modeling from tomography and designs the guide individually with normal injection mold method, it does not have a software that measures angular disorder with image processing, does not measure and does not take the guide from 3D printing.
The summary of the application numbered TR2019/01956, which emerged as a result of technical research, is as follows: "This invention relates to a system that determines the amount and shape of the disorder to be corrected after comparing the right and left extremities by performing punctuation and/or line drawing procedures in the right and left radiographic extremity images taken from the person for customized joint and bone structuring, creates the osteotomy navigation according to the determined disorder amount and shape and then determines the prosthesis sizes."
The system relates to a system that provides customized joint and bone structuring, and it does not mention a structure that can provide a solution to the disadvantages mentioned above. In conclusion, it was deemed necessary to make an improvement in the relevant technical field due to the disadvantages described above and the inadequacy of the existing solutions on the subject.
The Object of the Invention
The invention aims to provide a structure having different technical features that are novel in this field, different from the embodiments used in the known state of art.
The primary object of the invention is to process X-ray, Computed X-ray, tomography, three- dimensional tomography images for each patient and to design a personal guide made from a personalized three-dimensional printing.
The object of the invention is to provide a system that has a web software that allows the images to be uploaded and planned and measured to measure the bone angular disorder of each patient through radiological images by providing customized solutions and that can process the data it receives from there and print the personalized osteotomy and screw guide on a three-dimensional printer.
An object of the invention is to provide a separate planning and measurement system for each patient and a 3D printing osteotomy guide and external plate screw guide system that are specially designed with the data obtained from this system and modeled with the patient's data to correct the angular disorder.
The object of the invention is to provide a system that enables the cases performed with classical surgery without using a guide to be made more smoothly and with customized corrections and osteotomy.
The invention, which is used in the field of orthopedic surgery in the medical sector to achieve the objects described above, is a system for automatically calculating the angle necessary to correct the varus or valgus deformity by measuring the anatomical axes of the femur and tibia, and for creating a guide, characterized in that it comprises the following:
• Software that enables marking on X-ray or tomography films uploaded by the doctor and detection of bone angular disorder in the patient with image processing techniques,
• 3D printer that enables the production of customized guide in accordance with the angular distortion calculated in the software,
• a guide having: o designable plate slot that fits into the plate implant after osteotomy and is used as an external screw guide, o The femoral support flaps used to fix the guide to the bone, o the osteotomy area that forms the part where the saw will enter the guide for cutting the bone and angled according to the angle measured in the software, o the locking hole connecting the Proximal (P) (Upper) and Distal (Lower) portions of the guide, which also provides height adjustment, o the guide wire hole for fixing the guide to the bone, o screw holes overlapping with the holes in the plate to fix the implant (plate) to the bone after osteotomy and to make external plating, o the skin flaps forming the part of the guide that comes over the skin and ensuring the adhesion of the guide to the skin, o the fixing screw connecting the Proximal and Distal portions of the guide, which also provides adjustable height.
Structural and characteristic features of the invention and all the advantages it provides will be understood more precisely with the Figures hereinbelow and the detailed explanation with references to these Figures; the evaluation should be made by taking these Figures and detailed explanation into consideration for this reason.
Figures for Understanding of the Invention
Figure 1 A, 1 B: Finding the center of the head of the femur with the help of tangents drawn on the head of the femur
Figure 2A, 2B: Finding the femoral head center with the help of squares and diagonals drawn on the femoral head.
Figure 5A, 5B: Finding the center of the distal joint face of the femur.
Figure 6A: Femur Anatomical Axis
Figure 6B: Femur Mechanical Axis
Figure 7A, 7B: Tibia Proximal Articular Surface Midpoint
Figure 8A, 8B: Middle point of the tibia distal joint face 8A: Middle of distal tibia joint face;
8B: The midpoint of the bones. Figure 9A, 9B: Middle point of the tibia distal joint face 9A: Middle of soft tissues, 9B: The middle of the Talus dome corresponds to the same place (the middle point of the Talus superior joint face shows the same point).
Figure 10A, 10B, 10C: Tibia axes. 10A: Mechanical axis; 10B: Anatomical axis; 10: The relationship between the anatomical (dark arrow) and mechanical axis (light arrow) of the tibia.
Figure 11 : An anatomical and mechanical axis of the femur in the frontal plane.
Figure 12A: Orientation line of the tibia distal joint in the frontal plane.
Figure 12B: Orientation line of the tibia proximal joint in the frontal plane.
Figure 13: Orientation line of the femur distal joint in the frontal plane.
Figure 14A, 14B: Orientation lines of the femur proximal joint in the frontal plane; 14A: Line connecting the femoral head center and the large trochanter apex, 14B: The line that connects the femoral head center with the midpoint of the neck of the femur.
Figure 15A, 15B: Orientation line of the femur proximal joint in the frontal plane, 15A: With the mechanical axis of the femur; 15B: Relationship of femur to anatomical axis.
Figure 16: Relationship of the orientation line of the femur proximal joint with the anatomical axis of the femur in the frontal plane.
Figure 17A, 17B: Orientation line of the femur distal joint in the frontal plane, 17A: With the mechanical axis of the femur; 17B: Relationship of femur to anatomical axis.
Figure 18: Relationship of the orientation line of the tibia proximal joint with the anatomical and mechanical axis of the tibia.
Figure 19: Relationship of the orientation line of the tibia distal joint with the anatomical and mechanical axis of the tibia in the frontal plane.
Figure 20: The mechanical axis of the lower extremity passes through the median 8±7 mm of the knee center in the frontal plane.
Figure 21 : If the mechanical axis of the lower extremity passes through the medial of the center of the knee more than 15 mm, there is varus deformity in the frontal plane.
Figure 22: If the mechanical axis of the lower extremity passes laterally to the center of the knee, there is valgus deformity in the frontal plane.
Figure 23: An mLDFA angle is drawn to see if there is a deformity in the femur in the frontal plane. This angle is 87.5±2.5 degrees on average. Figure 24: Varus or valgus deformities occur in the femur in the frontal plane.
Figure 25: An MPTA angle is drawn to see if there is a deformity in the tibia in the frontal plane. This angle is 87.5 ± 2.5 degrees on average.
Figure 26A, 26B: Deformity of the tibia in the frontal plane, 26A: If MPTA is less than 85 degrees, it indicates varus deformity in the tibia; 26B: If the MPTA is greater than 90 degrees, it indicates valgus deformity in the tibia.
Figure 27: An JLCA angle is drawn to see if there is a deformity in the knee joint in the frontal plane. This angle is normally 0 degrees.
Figure 28A, 28B: Deformity of the knee joint in the frontal plane; 28A: If JLCA is greater than 2 degrees and in the medial, it indicates valgus deformity in the knee joint; 28B: If JLCA is greater than 2 degrees and in the lateral, it indicates varus deformity in the knee joint.
Figure 29A, 29B: 29A: The midpoints of the joint surfaces are aligned in the normal knee joint; 29B: The midpoints of the knee joint surfaces are compared in order to investigate whether there is subluxation in the knee joint.
Figure 30: The tibial plateau joint surfaces of the knee joint are aligned. There is no angle between them. If there is an angle, it may be the cause of the deformity.
Figure 31 : Trochanteric headline.
Figure 32A, 32B: Relationship of the trochanter-head line to the femoral mechanical axis, 32A: Normal hip; 32B: Coxa vara.
Figure 33A, 33B: Relationship of the trochanteric head line to the femoral anatomical axis, 33A: Normal hip; 33B: Coxa vara.
Figure 34A, 34B: Relationship of the head and neck line to the anatomical axis, 34A: Normal hip; 34B: Coxa vara.
Figure 35: Relationship between the distal tibia joint orientation line and the tibia mechanical axis (left) and the anatomical axis (right).
Figure 36A: Hip rotation center;
Figure 36B: Knee rotation center;
Figure 36C: Femoral mechanical axis.
Figure 37: Finding the knee rotation center. Figure 38A, 38B: Drawing of femoral anatomical axis in the sagittal plane, 38A: Finding the midline of the femur; 38B: Drawing the anatomical axis of the proximal section.
Figure 39A: Drawing of distal section anatomical axis;
Figure 39B: There is a 10-degree angle between the proximal and distal part.
Figure 40A, 40B, 40C: Drawing of tibia mechanical axis in the sagittal plane; 40A: Saturation is applied from the joint face edges, 40B: There is a midpoint between the two saturations; 40C: The two midpoints are joined.
Figure 41 A, 41 B: Anatomical axis of tibia in the sagittal plane
Figure 42A, 42B, 42C: Orientation line drawing of the femur distal joint in the sagittal plane; 42A: When the growth cartilage is open; 42B: After the growth cartilage is calcified; 42C: When there is no growth cartilage or trace of it.
Figure 43A, 43B: Tibia orientation lines in the sagittal plane; 43A: Proximal tibia; 43B: Distal tibia.
Figure 44A, 44B: The relationship between the anatomical axis of the femur and the distal femur orientation line; 44A: aPPTA angle between the anatomical axis of the femur and the distal femur orientation line; 44B: The anatomical axis cuts the distal orientation line at 2/3 anterior.
Figure 45A, 45B: Anatomical axis relationship with orientation line of the tibia proximal joint in the sagittal plane.
Figure 46: Anterior distal tibial angle.
Figure 47A: Normal alignment in the sagittal plane of the knee,
Figure 47B: Posterior subluxation.
Figure 48: The mechanical axis of the lower extremity passes in front of the knee rotation center (c) in the sagittal plane while the knee is in full extension.
Figure 49: While the knee is in 5-degree flexion, the rotation centers of the hip (a), knee (b) and ankle (c) are in the same line.
Figure 50A, 50B: Malalignment in the lower extremity in the sagittal plane; 50A: Flexion; 50B: Extension alignment disorder.
Figure 51 A, 51 B: Sagittal malalignment test 1
Figure 52: The sagittal malalignment test 1 indicates the deformity of the recurvatum above 87 degrees aPDFA, and the procurvatum below 79 degrees aPDFA. Figure 53A, 53B, 53C: Sagittal malalignment test 3; 53A Normal knee joint; 53B: Extension array disorder; 53C: Flexion alignment disorder is measured.
Figure 54: It is a different view of the proximal part of the guide.
Figure 55: It is a different view of the distal part of the guide.
Figure 56: This is a different view of the guide screw.
Figure 57: This is an indication of the positioning of the guide on the femur bone.
The drawings are not necessarily drawn to scale and details which are not necessary for the understanding of the present invention may be omitted. In addition, elements that are substantially identical or have substantially identical functions are denoted by the same reference signs.
List of the Reference Numbers
10. Guide
11 . Designable plate slot
12. Femur support flaps
13. Osteotomy area
14. Locking hole
15. Wire hole
16. Screwing holes
17. Skin flaps
18. Fixing screw
20. Software
30. 3D printer
P. Proximal part (Top)
D. Distal part (Lower)
I. Plate (Implant)
F. Femur bone Detailed Description of the Invention
In this detailed description, the preferred embodiments of the invention are merely described for a better understanding of the subject matter and without any limiting effect.
Invention relates to a system with a software (20) that automatically calculates the angle necessary to define and correct varus or valgus deformity by measuring the anatomical axes of the femur and tibia by carrying standard deformity measurement techniques to the digital environment. An Osteotomy guide and an external plate screw guide are formed in the 3D printer (30) according to the calculated angle.
Markings are made on X-ray or tomography films uploaded to the software (20) by the doctor and bone angular disorder in the patient is detected by placing markings and symbols by processing with image processing techniques.
The working principle of the software (20) is as follows;
Calculation of the mechanical and anatomical axes of the femur and tibia through radiological images in the software:
Femur Mechanical Axis
It is necessary to find the center of the proximal and distal joints of the femur in order to draw the mechanical axis of the femur.
1 . Two tangents are drawn on the femoral head parallel to each other from the top and bottom. The points of contact of the tangents with the femoral head (Figure 1A, points a and b) are coupled. Thus, the diameter of the circle is found. A tangent is drawn from the medial, the point where these tangent crosses the diameter of the saturation from the point of contact (Figure 1 B, point c) to the femoral head is the center of the femoral head (M).
2. The shape is made into a square by adding two vertical tangents from the medial and lateral to the 2 tangents drawn in Figure 1 A-1 B (Figure 2A). The diagonals of the square are drawn and the center is found (Figure 2B).
Center of the distal joint face of the femur: It can be found in two ways:
1 . The apex of the femoral notch can be taken (Figure 5A). The femoral notch fits the center of the femur distal joint face.
2. The outer edges of the femoral condyles are measured, and the midpoint is taken. This point fits the apex of the femoral notch even if it is not complete (Figure 5B). Femur Mechanical Axis: After the central points of the proximal and distal joint face of the femur are found, these two points are joined, and the mechanical axis of the femur is drawn (Figure 6A).
Femur Anatomical Axis:
The anatomical axis of the femur is drawn by joining the midpoints of the lines drawn vertically from 2 or 3 places to the diaphysis of the femur (Figure 6B).
These markings are processed in the software (30) and calculated by placing reference marks and symbols on X-ray images.
Tibia Mechanical Axis
It is necessary to find the center of the proximal and distal joints of the tibia in order to draw the mechanical axis of the tibia.
The center of the tibia proximal joint face is located in two ways:
1 . It is taken between two tibial spines (Figure 7A)
2. The midpoint of the tibial plateau is taken (Figure 7B). A suturation is performed on the joint face from the point where the inner tibial plateau ends for this. A second suturation is performed from the end of the outer tibial plateau in the same way. These saturations are joined vertically and the midpoint shows the center.
The center of the distal joint face of the tibia is located in four ways:
1 . The distal tibia joint face has a midpoint (Figure 8A).
2. The midpoint of the tibia and fibula bones is found (Figure 8B).
3. The midpoint of the soft tissues is found (Figure 9A).
4. The Talus has a midpoint (Figure 9B).
Middle points of the proximal and distal joint face of the tibia are joined and the mechanical axis of the tibia is drawn (Figure 10a).
Tibia Anatomical Axis
There are midpoints of the lines drawn vertically in 2 or 3 places to the diaphysis of the tibia. The anatomical axis of the tibia is drawn by combining these points (Figure 10b).
Anatomical-Mechanical Axis Relationships in Tibia The mechanical axis is a straight line. The anatomical axis may be curved (such as the anatomical axis of the femur in the sagittal plane) since the anatomical axis is the line connecting the midpoints of the diaphysis.
The anatomical and mechanical axes of the tibia are parallel to each other and there are only a few millimeters of gap between them in the frontal plane. The angle between the two axes is 0 degrees. Therefore, the anatomical and mechanical axis is considered the same (Figure 10C) in practice.
The anatomical and mechanical axes of the femur are different in the frontal plane. There is an average angle of 7 degrees between the two axes. Normally, there may be a deviation of 2 degrees (Figure 1 1 ).
Orientation Lines of Tibia Joint
The subchondral line of the distal tibia is taken as a basis to draw the orientation line of the tibia distal joint in the frontal plane (Figure 12A).
The concave points of the subchondral line of the two tibial plateaus are joined to draw the orientation line of the tibia proximal joint in the frontal plane (Figure 12B).
Orientation Lines of Femur Joint
The subchondral line of the distal femur is taken as a basis to draw the orientation line of the femur distal joint in the frontal plane (Figure 13).
Two lines are used for orientation of the femur proximal joint in the frontal plane.
1 . The line that connects the large trochanter apex with the femoral head center (Figure 14A).
2. The line that connects the femoral neck midpoint with the femoral head center (Figure 14B).
Relationship between Joint Orientation Lines and Mechanical and Anatomical Axes
The angles measured to indicate these relationships are usually defined by 4 uppercase letters. The first letter describes the direction of the angle. The angle direction is either lateral or medial if the angle is in the frontal plane. It is either anterior or posterior if it is in the sagittal plane. Therefore, the first letter is one of the initials L, M, A or P, which are the first letters of direction words.
The second letter indicates whether the angle is proximal or distal to the bone. The second letter is the letter P in the proximal and the letter D in the distal. The third letter indicates which bone (tibia, femur) the angle belongs to. The third letter is T if the angle belongs to tibia, and F if it belongs to femur.
The fourth letter is the same in all of them, and the initial letter of the angle word is A.
Unlike these, the definition of 4 capital letters angle can be preceded by the lower case letter a or m. The letter a indicates that the angle is drawn according to the anatomical axis, and the letter m indicates that it is drawn according to the mechanical axis.
1 . mLPFA: The line connecting the femoral head center and the trochanter apex makes an average of 90 degrees (at least 85, at most 95 degrees) in the lateral side with the mechanical axis of the femur. This angle is called the Lateral Proximal Femoral Angle (mLPFA) (Figure 15A).
2. aMPFA: This line connecting the femoral head center and the trochanter apex makes an average of 84 (at least 80, at most 89) degrees in the medial with the anatomical axis. This angle is called the Medial Proximal Femoral Angle aMPFA (Figure 15A).
3. aMNSA: The line connecting the femoral head center with the midpoint of the neck of the femur makes an average of 130 (at least 124, at most 136) degrees in the medial with the anatomical axis. This angle is called the Medial Neck-Shaft Angle aMNSA (Figure 16).
4. mLDFA and aLDFA: The distal femur joint orientation line makes an average of 87 degrees (at least 85, at most 90 degrees) in the lateral side with the mechanical axis of the femur (Figure 17A). This angle is called the mechanical Lateral Distal Femoral Angle (mLDFA). This line makes an average of 81 (at least 79, at most 83) degrees laterally with the anatomical axis (Figure 17B). This angle is called the anatomical Lateral Distal Femoral Angle (aLDFA).
5. mMPTA: The proximal tibia joint orientation line makes an average of 87 degrees (at least 85, at most 90 degrees) in the medial with the mechanical axis of the tibia (Figure 18). This angle is called the Medial Proximal Tibial Angle (mMPTA). This line makes the same angle in the medial with the anatomical axis. Because the anatomical and mechanical axis of the tibia is considered the same.
6. mLDTA: The distal tibia joint orientation line makes an average of 89 degrees (at least 86, at most 92 degrees) in the lateral with the anatomical and mechanical axis of the tibia (Figure 19). This angle is called the Lateral Distal Tibial Angle (mLDTA).
B. FRONTAL PLAN MALALIGNMENT TEST (MAT)
The first thing we want to know is the answer to the question 'Is there deformity?’ when we encounter a phenomenon that is suspicious of deformity. Some deformities are too obvious to leave room for doubt. Most of the deformities are understood when the necessary measurements are made. These measurements (malalignment test) should be performed routinely in deformity whether the deformity is significant or not. Because the obtained data is necessary for the subsequent operations.
Malalignment Test 1
The purpose of this test is to find the answer to the question "Is there deformity?". The femur is located in the center of the head and ankle. The mechanical axis of the lower extremity is drawn by combining these two points. This line passes through the median 8±7 mm of the index center (Figure 20).
It is considered normal that the mechanical axis of the lower extremity passes through the medial up to 15 mm from the center of the knee. However, it is called the Mechanical Axle Deviation (MAD) if the mechanical axis passes through the medial or lateral more than 15 mm (the distance is not important). There is varus deformity if the MAD is in the medial and greater than 15mm (Figure 21 ). There is a valgus deformity if the mechanical axis of the lower extremity passes laterally to the center of the knee (the amount is not important) (Figure 22).
Malalignment Test 2
The answer to the question "Where is the deformity; is it in the femur?" is sought in this test. The Lateral Distal Femoral Angle (mLDFA) is measured for this. The femur mechanical axis is drawn by combining the femur head center with the femur distal joint face center. Then, the distal femur orientation line is drawn by combining the lowest subchondral points of the femoral condyles. These two lines form an angle (mLDFA) on the outside of the femur. This angle is normally 87.5±2.5 degrees (Figure 23).
There is deformity in the femur and it indicates varus deformity if this angle is greater than 90 degrees. It indicates valgus deformity in the femur if the angle is less than 85 degrees (Figure 24).
Malalignment Test 3
The answer to the question "Where is the deformity; is it in the tibia?" is sought in this test. The Medial Proximal Tibial Angle (MPTA) is measured for this. The tibia mechanical axis is drawn by combining the tibia proximal joint face center with the tibia distal joint face center. Then, the proximal tibia orientation line is drawn by combining the lowest subchondral points of the tibial plateaus. These two lines form an angle (MPTA) on the inside of the tibia. This angle is normally 87.5±2.5 degrees (Figure 25). There is deformity in the tibia and this is varus deformity if this angle is less than 85 degrees (Figure 26A). There is deformity in the tibia and this is valgus deformity if the angle is greater than 90 degrees (Figure 26B).
Malalignment Test 4
The answer to the question "Where is the deformity; is it in the knee joint?" is sought in this test. JLCA (Joint line convergence angle) is measured between the femoral and tibial knee joint lines to answer this question. The distal femur orientation line is drawn by combining the lowest subchondral points of the femoral condyles. Then, the proximal tibia orientation line is drawn by combining the lowest subchondral points of the tibial plateaus. These two lines are parallel to each other. There may be an angle of up to 2 degrees between them. An angle greater than 2 degrees indicates that the deformity is in the knee joint (Figure 27). There is a valgus deformity in the knee joint if this angle is greater than 2 degrees and in the medial (Figure 28A). There is varus deformity in the knee joint if JLCA angle is greater than 2 degrees and, in the lateral, (Figure 28B).
Malalignment Test 5
This and subsequent tests are performed if necessary. First, the answer to the question "Is there subluxation in the knee joint?" is sought. Perpendicular lines are drawn from the edges of the femur distal joint face and the proximal joint face of the tibia, and the middle point of the distance between these perpendicular lines is found and marked for this.
These two points are normally in line. The distance between them is considered normal up to 3 mm (Figure 29A). The cause of malalignment is knee subluxation if there is a distance of more than three mm (Figure 29B).
Is there condylar malalignment?
Joint surfaces of both femoral condyles and both tibial plateaus are drawn separately. The joint surface lines of both tibial plateaus follow each other, there is no angle or stair between them. Condylar malalignment occurs between the tibial plateau surfaces if the parallelism is distorted, that is, if there is an angle between them or if there is laddering. The same is true for femoral condyles, but since the femoral condyles are round, they are not as significant as in the tibial plateau (Figure 30).
Malorientation Test (MOT)
MAD occurs when there is malorientation on the joint surfaces of the knee joint. This is easily determined by the MAT (Malalignment Test). It reveals malorientation as well as mechanical axis deviation in the MAT knee joint for this reason. The situation is different in the hip and ankle. Mechanical Axle Deviation (MAD) is usually invisible or minimal when there is deformity at the distal end of the tibia and proximal end of the femur, close to the hip and ankle centers.
The deformity that occurs near the hip and ankle cannot be revealed with a MAT for this reason. We should do the hip and ankle MOT after MAT if we want the deformity analysis to be complete.
Hip MOT Malorientation test 1 a. The trochanter apex and the femoral head are combined with a central line (Figure 31). b. The femur mechanical axis is drawn. c. The mLPFA formed on the side is measured. (Figure 32). d. Normally, it is 90 degrees. (Figure 32A).
(at least 85, at most 95 degrees) (See Figure 15A)
If the angle is less than 85 degrees, there is coxa valga, if the angle is greater than 95 degrees, there is coxa vara deformity.
Malorientation test 2 (Figure 33) a. The trochanter apex and the femoral head are combined with a central line. b. The femur anatomical axis is drawn. c. The mLPFA formed in the medial is measured. d. It is normally 84 degrees (at least 79, at most 89).
Malorientation test 3 (Figure 34) a. The center of the femoral head and the middle point of the femoral neck are combined with a line. b. The femur anatomical axis is drawn. c. The aMNSA formed in the medial is measured. d. It is normally 130 degrees (at least 124, at most 136).
If the angle is less than 124 degrees, there is coxa vara, if the angle is greater than 136 degrees, there is coxa valga deformity.
Ankle MOT
Malorientation test 4 (Figure 35). a. The distal tibia joint orientation line is drawn b. The anatomical or mechanical axis of the tibia is drawn. c. The lateral LDTA is measured, d. Normally 89°( at least 86° at most 92‘).
If the angle is less than 86 degrees, there is valgus, if the angle is greater than 92 degrees, there is varus deformity.
C. SAGITTAL PLANE DEFORMITIES AND MALORIENTATION TESTS
The alignment of the hip, knee and ankle in the sagittal plane varies during normal knee movement and walking since the knee joint moves in the sagittal plane. Dynamic factors should also be considered in the evaluation of sagittal plane deformity even though static evaluations are generally sufficient in the analysis of frontal deformities.
Femur Mechanical Axis
It is necessary to find the hip and knee rotation center in order to draw the mechanical axis of the femur in the sagittal plane (Figure 36).
Hip rotation center: It is the center of the femoral head on lateral radiography. This center is found as described in the frontal plane (Figure 36A).
Knee rotation center: It is the point where the line that sustains the femoral posterior cortex on lateral radiography intersects with the Blumensaat’s line (Figure 37).
The hip and knee rotation centers are joined and the femur mechanical axis is drawn (Figure 36C).
Femur Anatomical Axis
Lines are drawn vertically in 2 or 3 places to the diaphysis of the femur, and the distances between the points where these lines cut both cortices are measured to draw the anatomical axis of the femur in the sagittal plane. The midpoints of these lines are found and marked. The anatomical axis of the femur is drawn by combining the middle points (Figure 38).
The femur is curved in the sagittal plane, not straight. Therefore, its anatomical axis is also curved. The anatomical axis of the proximal and distal halves of the femur is drawn separately due to this curvature. There is normally a 10-degree angle between the two. (Figure 39).
Tibia Mechanical Axis
It is necessary to find the center of the proximal and distal joints of the tibia in order to draw the mechanical axis of the tibia in the sagittal plane. Tibia proximal joint center: On the lateral radiography, a saturation is performed from the anterior and posterior ends of the proximal joint face of the tibia, and the middle point of the distance between the two saturations shows the proximal joint center of the tibia (Figure 40).
Tibia distal joint center: On lateral radiography, a saturation is performed from the anterior and posterior end of the tibia distal joint face, the middle point of the distance between the two saturations shows the tibia distal joint center (Figure 40A,B).
The tibia mechanical axis is drawn by combining the tibia proximal and distal joint face centers (Figure 40c).
Tibia Anatomical Axis
There are midpoints of the lines drawn vertically from 2 or 3 places to the diaphysis of the tibia, these are joined and the anatomical axis of the tibia is drawn (Figure 41 ).
Orientation Line of Distal Femur
It is the line connecting the most anterior and posterior points of the growth plate in those with open growth plate (Figure 42A). The calcified line of the growth cartilage is taken as a basis after the growth plate is closed (Figure 42B). If this is also lost, the points where the femoral condyles meet with the metaphysis are taken as a basis and these points are joined and the orientation line of the distal femur in the sagittal plane is drawn (Figure 42C).
Orientation Lines of Tibia
The proximal tibia orientation line is the flat subchondral line under the plateaus (Figure 43 A).
The distal orientation line is the line drawn between the end points of the anterior and posterior lips of the tibia (Figure 43B).
Relationship Between Orientation Lines and Anatomical and Mechanical Axes
1. aPDFA angle: The distal femur orientation line makes an average angle of 83 degrees (at least 79, at most 87 degrees) in the posterior with the anatomical axis of the femur. This angle is called the Posterior Distal Femoral Angle (aPDFA) (Figure 44A). The anatomical axis of the femur cuts the distal femur orientation line at 2/3 anterior (Figure 44B).
2. aPPTA angle: It is the angle formed by the sagittal mid-diaphysical line (anatomical axis of the tibia) cutting the proximal tibia joint orientation line (this point is usually 1/5 anterior to the joint line) (Figure 45). This angle is called the Posterior Proximal Tibial Angle (aPPTA). It is 81 degrees on average (at least 77, at most 84 degrees).
3. aADTA angle: The distal tibia joint orientation line makes an average angle of 80 degrees (at least 78, at most 82 degrees) with the anatomical axis of the tibia. This angle is called the Anterior Distal Tibial Angle (aADTA) (Figure 46).
The hip, knee and ankle, which are the three large joints in the lower extremity, can each move in the sagittal plane and correct for the malalignment. Therefore, lower extremity sagittal plane deformities are better tolerated compared to those in the frontal plane. This is particularly true for recurvatum and, to a lesser extent, procurvatum deformities.
Another reason for malalignment in the sagittal plane is knee subluxation. The midpoint of the sagittal widths of the femoral condyles is at the same alignment with the midpoint of the sagittal widths of the tibial plateaus. The displacement of the sagittal middle point of the tibia in front of the sagittal middle point of the femur is defined as anterior and posterior displacement is defined as posterior subluxation (Figure 47).
Sagittal Plan Lower Extremity Mechanical Axis
The line connecting the hip rotation center (a) (femoral head center) and the ankle rotation center (c) is the mechanical axis of the lower extremity in the sagittal plane (Figure 48). (Knee rotation center (c))
The lateral process of the talus is accepted as the ankle rotation center (c). The sagittal mechanical axis passes through the anterior of the rotation center of the knee joint while the knee is in full extension. This allows the knee to be locked at full extension.
Normally, the rotation centers of the hip, knee and ankle are located on the same line in 5e- 10e knee flexion (Figure 49).
Sagittal Plan Malalignment Test (MAT)
When performing the malalignment test in the frontal plane, our aim is to find the question of "Is there deformity?" and where is the place, if any. Likewise, MAT is made to find out whether there is a deformity in the sagittal plane and where to find the answer to the questions. In particular, what we are looking for in MAT is whether there is flexion and extension alignment disorder.
Flexion alignment disorder: There is flexion alignment disorder if the mechanical axis in the sagittal plane does not pass through the anterior of the knee rotation center in the radiography taken at the maximum extension of the knee (Figure 50A). Extension alignment disorder: There is an extension alignment disorder in the sagittal plane, if the knee can passively be extended more than 5 degrees. (Figure 50B). The doctor should be with the patient during the X-ray in order to decide on the presence of such malalignment. For example, it can be assumed in a patient without flexion alignment disorder that there is flexion alignment disorder in the radiography taken in the flexion position. Therefore, the MAT in the sagittal plane is not as precise as in the frontal plane and can be misleading.
Sagittal Malalignment Test 1
The answer to the question "Is there any deformity in the distal of the femur?" is sought with this test. a. The femur anatomical axis is drawn. b. The distal femur orientation line is drawn. c. Posterior PDFA between these two lines is normally 83 degrees on average (at least 78, at most 88 degrees). (Figure 51 )
Sagittal Malalignment Test 2
The answer to the question "Is there any deformity in the proximal of the tibia?" is sought with this test. a. The tibia anatomical axis is drawn. b. The aPPTA angle formed in the posterior is found by drawing the proximal tibia joint orientation line. If the aPPTA angle is less than 77 degrees, there is a procurvatum deformity in the proximal tibia, and if it is greater than 85 degrees, there is a recurvatum deformity (Figure 52).
Malalignment Test 3
“Is there any contracture in the knee joint?" is investigated with this test. The anterior cortices of the femur distal and proximal tibia are drawn on radiographs taken at full extension of the knee. There is normally no angle between these two lines. There is a flexion and extension alignment disorder according to the direction of the angle if an angle is formed between these two lines (Figure 53).
After the radiological image images uploaded to the anatomical and mechanical axes software (20) are processed in open source software such as openCV and Phyton and automatically calculated by placing markings and symbols, the doctor records these data after the bone angular disorder in the patient is defined as varus or valgus deformity in the software. It is known at what angle the bone will be cut, so an appropriate osteotomy guide is designed in line with the data obtained.
The data received from the software program (20) can be transferred to SolidWorks etc. A personal three-dimensional osteotomy and screw guide (10) is printed, which is modeled in a program, processed according to personal measurement data, transferred to a 3D printer (30) and allowed to externally screw the implant of the desired brand at the angle and size desired by the doctor.
There is a designable plate slot for different brands (1 1 ) that fits into the plate (I) after osteotomy and is used as an external screwing guide in the guide (10) subject to the invention.
The femoral support flaps (12) are used to fix the 3D guide (10) to the bone.
The osteotomy area (13) that can be adjusted with a personal angle is the area where the saw will enter the guide (10) for osteotomy, angled according to the angle measured in the software (20).
The locking hole (14) is the screwing hole connecting the Proximal (P) (Upper) and Distal (D) (Lower) portions of the guide (10), which also provides the hole for the height adjusting screw.
The Kirschner Wire guide wire hole (15) allows the guide (10) to be fixed to the bone.
Designable screwing holes (16) are screwing holes overlapping with the holes in the plate (I) to make external plating to fix the implant (plate (I)) to the bone after osteotomy.
The skin flaps (17) are the part of the guide (10) that overlaps the skin. It ensures that the guide (10) is attached to the skin.
The fixing screw (18) is the screw produced by 3D printing, which connects the Proximal (P) and Distal (D) portions of the guide (10), which also provides adjustable height.
The process steps performed by the system of the invention are as follows:
• Pressing the customized DFO (Distal femoral osteotomy) osteotomy and external screw guide (10) in the 3D printer (30) in accordance with the angles measured and calculated in the software (20) and the selected plate (I),
• Fixing the femoral bone (F) to the bone with the help of wire or pin through the femoral support flaps (12) and Kirschner wire holes (15) after the necessary muscle and tissue elements are removed by the surgeon, • Performing bone osteotomy at the angle determined from the saw bone incision area (13) printed at a personal angle, (decides on the open and closed wedge osteotomy by marking it in the doctor's software (20)),
• Removing the distal (D) (lower) part of the guide (10) from the place where it is fixed,
• The connection of the Proximal (P) (upper) and Distal (D) (lower) portions of the guide with the fixing screw (18) from the reference locking hole (14) is made with the help of the fixing screw (18). Here, the surgeon adjusts the height of the guide so that it is on the bone if it does not perform external screwing.
• Plate (I), which is designed according to the desired brand model, is placed in the plate slot (1 1 ) at the bottom of the guide (10) and fixed to the bone,
• Screwing the lower side with the help of the distal (D) (lower) part of the guide (10) with the plate (I) thanks to the fact that the screwing holes (16) on the guide (10) are in the same place as the holes of the plate (I),
• The guide (10) is connected to the wire hole (15) with the help of the fixing screw (18) so that the proximal (P) (upper) part is on the skin,
• Correcting the bone according to the correction angle measured in the software (20) by the surgeon and placing the guide (10) proximal (P) (upper part) on the skin, fixing the proximal (P) part of the plate (I) to the bone with the help of small incisions on the skin with the help of screwing holes (16),
The system works as follows. The data obtained from the bone measurement and osteotomy software (20) are modeled individually in the solidworks program and produced in a 3D printer (30). The customized guide (10) in the 3D printer (30) consists of two parts.
The first Proximal (P) Upper piece is fixed to the bone and osteotomy is performed with a guide produced with a personalized angle.
After the second distal (D) (lower) part is joined with the part, the YTO plate (I) is placed in the guide and the doctor corrects the bone at the angle he/she measures and the operation is completed by fixing the plate (I) externally (without damaging the skin) with the help of the screwing holes (16) on the guide with the help of the upper and lower parts of the guide (10).