Planning for corrective osteotomy of the femoral bone using 3D-modeling. Part I

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Abstract


Introduction. In standard planning for corrective hip osteotomy, a surgical intervention scheme is created on a uniplanar paper medium on the basis of X-ray images. However, uniplanar skiagrams are unable to render real spatial configuration of the femoral bone. When combining three-dimensional and uniplanar models of bone, human errors inevitably occur, causing the distortion of preset parameters, which may lead to glaring errors and, as a result, to repeated operations.

Aims. To develop a new three-dimensional method for planning and performing corrective osteotomy of the femoral bone, using visualizing computer technologies.

Materials and methods. A new method of planning for corrective hip osteotomy in children with various hip joint pathologies was developed. We examined the method using 27 patients [aged 5–18 years (32 hip joints)] with congenital and acquired femoral bone deformation. The efficiency of the proposed method was assessed in comparison with uniplanar planning using roentgenograms.

Conclusions. Computerized operation planning using three-dimensional modeling improves treatment results by minimizing the likelihood of human errors and increasing planning and surgical intervention 
accuracy.


Introduction

For nearly all children with congenital and acquired pathology of the hip joint (dysplasia or consequences of infectious damage, trauma, or avascular necrosis), surgical correction of proximal femur anteversion is required. The results of orthopedic surgery directly depend on accurate pre-operative planning and intraoperative execution.

In standard planning of the corrective osteotomy of the femur, the scheme of the surgical intervention is prepared using a skiagram, i.e., a uniplanar paper medium created on the base of an X-ray image. Surgical hardware for osteosynthesis is selected by the apposition to an X-ray picture [1]. The uniplanar skiagram cannot render the true 3D configuration of the femur for visualization. During surgery, when superimposing the uniplanar model and 3D bone, human errors unavoidably occur, causing distortions of preset parameters and leading to gross errors that may result in additional surgeries.

The key feature of modern imaging technologies is that they possess practically infinite possibilities, allowing an accurate topical diagnosis via the calculation of parametric data and implementation of the virtual modeling of any 3D object.

Aim of the study

The goal of the study is to develop a new 3D method for planning and performing corrective osteotomy of the femur using visualizing computer technologies and to assess the efficacy of the proposed method in comparison with uniplanar planning using X-ray images.

Materials and methods

A new method was developed for the planning of corrective osteotomy of the femur in children with various pathologies of the hip joint (application for an invention: “A method of corrective osteotomy of the femur,” certificate of receipt No. 2016105166 of 16.02.2016), involving 27 patients aged 5–18 years (32 hip joints) with congenital and acquired deformities of the femur.

X-ray images of hip joints, paper, pencils, and glue were used for the development of the skiagrams.

Computed tomography scans of the femurs of the same patients and adapted software were used for 3D modeling. A 3D printer (ULTRA 3SP; EnvisionTeC, Germany) was used for prototyping.

Techniques of pre-operative planning

Stages of uniplanar planning for corrective osteotomy of the femur

X-ray films of the hip joints were obtained from frontal views of the middle position and internal rotation of the femur and from Lauenstein views. The diaphysis and femoral neck axes were traced. The true, projected caput–collum–diaphyseal angle (CCD) was measured. The mathematical tables from Strzyzewski [2] and Shartlain [3] were used for calculations of true femoral anteversion.

On the X-ray image, the angle between the neck axis and a line tangent to the external outline of the diaphysis (b = 90°) was measured. The triangular portion edf is the dissected wedge on the skiagram (40°). 
Angle edf is equal to angle с, с is the correction degree, a is the required CCD (130°), and de is the osteotomy line (2.5 cm). When performing an osteotomy with wedge dissection, first, an osteotomy of the femur is performed; ed, the distance ef is measured out and the dissection of edf is performed (Fig. 2) [4].

The obtained data were transferred to a paper skiagram on which a wedge is cut out and the fragments are compared (Fig. 3).

Finally, a conventional representation of the femur reconstruction is obtained based on a uniplanar model (Fig. 4).

Using this method for pre-operative planning, it is possible to conditionally model the correction of CCD; however, it is impossible to accurately calculate the correction of the femoral anteversion because the angle is located in the plane perpendicular to the plane of the X-ray image made from the anteroposterior view. Intraoperationally, the anteversion angle should be set approximately on the basis of visual and palpatory assessment of the femur.

Stages of 3D modeling of corrective osteotomy of the femur

1. Using computed tomography data, a 3D model of the femur is created by means of conversion (Fig. 5).

2. From the various views (perspective, right, left, top, and front), CCD is calculated. CCD is defined by the intersection of the lines through the femur diaphysis and the femoral neck axes in the frontal plane, which equals 95.66° (Fig. 6).

3. The femoral anteversion is calculated. This angle is defined by the intersection of the neck axis line and a line tangent to the femoral condyles, which equals 3.45° (Fig. 7).

4. For osteosynthesis planning, a 3D model of metal hardware is added to the 3D model of the femur from the created virtual base; in this case, it requires a 130° DePyu Synthes LCP pediatric hip plate. For positioning of the plate, a guide pin is virtually drawn (Fig. 8).

5. Intertrochanteric osteotomy of the femur is virtually performed (Fig. 9).

6. In the top view, the 3D program shows the rotation of the distal femur to the planned anteversion (15°), which is formed by the intersection of the neck axis line with the line tangent to the femoral condyles. On the proximal and distal femur, proximal and distal markers were created perpendicular to the osteotomy plane. The markers were connected to the proximal and distal femur regions, respectively. For further modeling, the distal femur, with the connected torsion marker, was returned to its initial position 
(Fig. 10).

7. The selection of the point of rotation to move the proximal femur to the planned CCD value (130°) plays a key role. The overlapping area of the distal and proximal femur regions corresponds to the area of the resected bone wedge; the angle of the bone wedge is 37.08°, and the base is 17.39 mm (Fig. 11).

8. After removal of the bone wedge, the distal and proximal femur regions are compared (Fig. 12).

Discussion

The data obtained when comparing the uniplanar planning technique with 3D modeling are presented in Table 1.

A comparative analysis of the 3D modeling and uniplanar planning calculations was performed in 27 patients (32 hip joints). The mean difference in measuring the angular indicators was 6° ± 2° (P < 0.05), and the difference in the linear indicators was 4 mm ± 2 mm (P < 0.05).

Pre-operative planning using uniplanar skiagrams had the following disadvantages:

Table 1

Comparison of the results obtained by calculation based on uniplanar planning and 3D modeling

Indicators

Uniplanar planning

3D modeling

Caput–collum–diaphyseal angle

91

95.66

Anteversion, °

3.45˚

Dissected wedge angle, °

30

37.08

Bone wedge base, mm

25

17.39

In the X-ray images, the hip joint structures overlap and shade each other, making a reliable assessment difficult. In such cases, patient positioning and the degree of the surgeon’s spatial reasoning are critical.

When superposing the uniplanar model and 3D bone, inaccuracies inevitably occur, leading to the distortion of preset parameters.

These challenges lead to errors during corrective osteotomy, which has an adverse effect on treatment outcomes.

The 3D technique differs from the uniplanar planning in the following ways:

The lines drawn from the different projections in the 3D program provide optimal accuracy of the calculation of angular values.

The use of 3D modeling allows the accurate planning of the correction of the femoral anteversion.

Errors in determining the true form and shape of the resected bone wedge are minimized.

A virtual catalogue of metal hardware permits the selection of the necessary fixator with optimal accuracy.

Several treatment options can be modeled and an optimal one selected to achieve successful treatment results.

Conclusion

The use of X-ray images for angular calculations is neither accurate nor reliable for pre-operative planning and performance of corrective osteotomy of the femur. The use of 3D modeling minimizes the possibility of human errors, which improves treatment results due to the increased accuracy of both the planning and surgical interventions [5]. The correct selection of osteotomy level, shape of the bone wedge, and type of metal hardware not only determines the course of surgery but also impacts the entire treatment outcome.

Competent surgical planning not only indicates the surgeon’s professionalism but also their work culture. In specialized orthopedic departments, reparative interventions require the compilation 
of high-quality pre-operative planning prior to surgery [1].

Corrective osteotomy of the femur using an individual template will be presented in the second part of this paper.

Information on funding and conflict of interest

The authors declare no conflicts of interest related to the publication of the present paper. The work was performed as part of the research approved by The Turner Scientific and Research Institute for Children’s Orthopedics, Saint Petersburg, Russian Federation.

Alexey G Baindurashvili

The Turner Scientific and Research Institute for Childrens Orthopedics

Author for correspondence.
Email: turner01@mail.ru
MD, PhD, professor, corresponding member of RAS, honored doctor of the Russian Federation, Director of The Turner Scientific and Research Institute for Children’s Orthopedics

Vladimir E Baskov

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: dr.baskov@mail.ru
MD, PhD, head of the department of hip pathology. The Turner Scientific and Research Institute for Children’s Orthopedics

Anastasia V Filippova

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: mmers@list.ru
MD, research associate of the scientific-organizational department. The Turner Scientific and Research institute for Children’s Orthopedics.

Pavel I Bortulev

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: pavel.bortulev@yandex.ru
MD, research associate of the department of hip pathology. The Turner Scientific and Research Institute for Children’s Orthopedics

Dmitry B Barsukov

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: dbbarsukov@gmail.com
MD, PhD, senior research associate of the department of hip pathology. The Turner Scientific and Research Institute for Children’s Orthopedics

Ivan Y Pozdnikin

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: pozdnikin@gmail.com
MD, PhD, research associate of the department of hip pathology. The Turner Scientific and Research Institute for Children’s Orthopedics

Sergei Y Voloshin

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: volochin_ortoped@mail.ru
MD, PhD, chief of the department of hip pathology. The Turner Scientific and Research Institute for Children’s Orthopedics

Tamila V Baskaeva

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: tamila-baskaeva@mail.ru
MD, orthopedic surgeon of the Turner Scientific and Research Institute for Children’s Orthopedics.

Mahmoud S Poznovich

The Turner Scientific and Research Institute for Childrens Orthopedics

Email: tamila-baskaeva@mail.ru
MD, PhD student of the Turner Scientific and Research Institute for Children’s Orthopedics

  1. Соколовский А.М., Соколовский О.А., Гольдман Р.К., Деменцов А.Б. Планирование операций на проксимальном отделе бедренной кости // Журнал медицинские новости. - 2005. - № 10. - С. 26-29. Доступно по: http://www.mednovosti.by/journal.aspx?article=1043. Ссылка активна на 06.07.16. [Sokolovskii AM, Sokolovskii OA, Gol’dman RK, Dementsov AB. Planirovanie operatsii na proksimal’nom otdele bedrennoi kosti. Zhurnal meditsinskie novosti. 2005;10:26-29. (In Russ).] Доступно по: http://www.mednovosti.by/journal.aspx?article=1043. Ссылка активна на 06.07.16.
  2. Басков В.Е. Ортопедохирургическое лечение детей с диспластическим маргинальным вывихом бедра: Дис. … канд. мед. наук. - СПб., 2009. [Baskov VE. Ortopedo-khirurgicheskoe lechenie detei s displasticheskim marginal’nym vyvikhom bedra. [dissertation] Saint Petersburg; 2009. (In Russ).]
  3. Мирзоева И.И., Гончарова М.Н., Тихоненков Е.С. Оперативное лечение врожденного вывиха бедра у детей. - Л.: Медицина, 1976. [Mirzoeva II, Goncharova MN, Tikhonenkov ES. Operativnoe lechenie vrozhdennogo vyvikha bedra u detei. Leningrad: Meditsina; 1976. (In Russ).]
  4. Баиндурашвили А.Г., Краснов А.И., Дейнеко А.Н. Хирургическое лечение детей с дисплазией тазобедренного сустава. - СПб.: СпецЛит, 2011. [Baindurashvili AG, Krasnov AI, Deineko AN. Khirurgicheskoe lechenie detei s displaziei tazobedrennogo sustava. Saint Petersburg: SpetsLit; 2011. (In Russ).]
  5. Brown G, Firoozbakhsh K, DeCoster T, et al. Rapid prototyping: the future of trauma surgery? J Bone Joint Surg [Am]. 2003;85-A(Suppl):49-55.

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CrossRef     2 citations

  • Ma YH, Shi TC. The Design of Deformed Femur Osteotomy System. Journal of Physics: Conference Series. 2018;1098:012007. doi: 10.1088/1742-6596/1098/1/012007
  • Baskov VE, Baindurashvili AG, Filippova AV, Barsukov DB, Krasnov AI, Pozdnikin IY, et al. Planning corrective osteotomy of the femoral bone using three-dimensional modeling. Part II. Pediatric Traumatology, Orthopaedics and Reconstructive Surgery. 2017;5(3):74. doi: 10.17816/PTORS5374-79

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Copyright (c) 2016 Baindurashvili A.G., Baskov V.E., Filippova A.V., Bortulev P.I., Barsukov D.B., Pozdnikin I.Y., Voloshin S.Y., Baskaeva T.V., Poznovich M.S.

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