EA034388B1 - Method of preoperative planning of surgical correction of foot deformation at level of midfoot - Google Patents

Abstract

The invention relates to medicine, and more particularly to traumatology and orthopedics and can be used for preoperative preparation of a patient for surgical correction of midfoot deformation when deformation components (angulation, shortening) are located in the sagittal plane. To determine reference lines and angles of bones of the midfoot and hindfoot with the purpose of assessing deformation thereof, many parameters are known, among which the following being used most often: talus-metatarsus angle (Meary angle) formed by anatomic axes of the talus and first metatarsal bone; calcaneal-metatarsus angle formed by anatomic axes of the calcaneum and first metatarsal bone and tibial-metatarsus angle formed by anatomic axes of the tibia and first metatarsal bone. The claimed invention allows to make preoperative planning of surgical correction more accurate and reliable due to more precise assessment of foot deformation, more comprehensive and complex assessment of reference lines and angles of the midfoot and hindfoot bones when determining its true deformation.

Description

The invention relates to medicine, namely to traumatology and orthopedics, and can be used for preoperative preparation of a patient for surgical correction of deformation of the middle part of the foot, when the components of the deformation (angulation, shortening) are located in the sagittal plane.

To determine the reference lines and angles of the bones of the middle and hindfoot to assess its deformation, many indicators are known, among which the following are most often used.

1) The tarsal-metatarsal angle (Meary angle), formed by the anatomical axes of the talus and the first metatarsal bones [1]. However, when finding the location of the mechanical axis of the first metatarsal bone relative to the neck of the talus in case of deformation, the accuracy of this method significantly decreases. In addition, the application of this method does not allow to determine the anatomical location of the head of the first metatarsal bone. Also, in the described method for determining the degree of deformation of the middle part of the foot does not provide for the definition of the peak deformation, which should be corrected.

2) The heel-metatarsal angle formed by the anatomical axes of the heel and first metatarsal bones [2]. However, the calcaneus deformity can also lead to a significant decrease in the accuracy of this method. In addition, the application of this method does not allow to determine the anatomical location of the head of the first metatarsal bone and the apex of deformation.

3) The tibial-metatarsal angle formed by the anatomical axes of the tibia and first metatarsal bones [3]. In this case, deformation at the level of the ankle joint or distal tibia also reduces the accuracy of determining the degree of deformation. As in the two previous analogues, the application of this method does not allow to determine the anatomical location of the head of the first metatarsal bone and the apex of deformation.

A known method that is closest to the claimed and which is adopted as a prototype [4]. The known method can be used to determine the degree of flat-valgus deformation of the foot. With this method, a clinical examination is carried out, an X-ray examination of the foot is performed. The X-ray is determined by the talus-1-metatarsal angle (TPU), the angle of inclination of the calcaneus (UNPK), the angle of the talus-navicular ratio (UTLS). This method is designed to assess the deformation of the middle part of the foot, the components of which are in the sagittal plane, with the aim of preoperative preparation for subsequent surgical correction. In both cases, an X-ray of the foot is performed with a load in the lateral projection, the results of which assess the location of the first metatarsal bone relative to the talus. The disadvantages of this prototype are a sufficiently high error allowed due to the limited information content of the foot deformity assessment in the case of deformities of the talus and heel bones, the inability to position the deformity apex and determine the anatomical location of the head of the first metatarsal bone, which leads to insufficiently accurate and reliable preoperative planning of surgical correction of the deformed foot .

The technical result of the claimed invention is to increase the information content of the deformation of the foot, as well as the accuracy and reliability of the preoperative planning of surgical correction, taking into account a more accurate assessment of the real state of the general deformation of the foot.

The specified technical result of the claimed method is implemented due to a more complete and comprehensive assessment of the reference lines and angles of the bones of the middle and hindfoot when determining its true deformation.

The specified technical result is achieved due to more informative indicators of true deformation, taken into account when developing preoperative planning of surgical correction, which is illustrated in FIG. 1-12. To obtain and take into account new information that improves the accuracy and quality of preoperative planning and, as a result, the final surgical result, a line of the articular surface of the talus block is drawn (line 1), and a line (line 2) is drawn anteriorly from the rear point of the articular block of the talus b and downward at an angle of 24 °, which coincides normally with the mechanical axis of the first metatarsal bone. The angle of deviation of the mechanical axis from line 2 determines the degree of angular deformation. Physiologically, the anterior point of the head of the first metatarsal bone is located on line 2 at point c, which is spaced bc = ab x 4.17 from the posterior point of the articular surface of the talus;

the intersection of line 2 with the mechanical axis of the first metatarsal bone is the apex of deformation d.

In the illustrative figures of the claimed invention are presented in FIG. 1 is a diagram of the construction of the articular line of the talus block (line 1) at the front and rear points (ab);

in FIG. 2 is a diagram of the construction of the mechanical axis of the first metatarsal bone (line 2);

in FIG. 3 - a diagram of the angle between line 1 and line 2 is 24; finding point (c) on line 2;

in FIG. 4 is a diagram for determining the anterior cortical layer of the head of the first metatarsal bone on

- 1 034388 mechanical axis;

in FIG. 5 is a diagram for determining the anatomical location of the mechanical axis of the first metatarsal bone and the location of the anterior cortical layer of the head of the first metatarsal bone relative to the articular surface of the talus block on the lateral radiograph of the foot with deformation at the level of the middle section;

in FIG. 6 is a diagram of constructing the mechanical axis of the first metatarsal bone (line 3), finding the apex of deformation (intersection of lines 2 and 3), determining the degree of deformation (angle between lines 2 and 3) and building the line of osteotomy (red dashed line);

in FIG. 7 is a schematic representation of the dosage correction of deformation of the middle section at the level of osteotomy with the cultivation of bone regenerate;

in FIG. 8-20 presents clinical examples of the use of the proposed method.

The essence of the claimed method is as follows. Line 1 is drawn through points a and b (edges of the talus block) and the distance from a to b is measured in millimeters (Fig. 1). After that, from point b, at an angle of 24 ° to line-1, draw line-2 (Fig. 2). In the absence of deformation, line-2 should coincide with the mechanical axis of the 1st metatarsal bone (Fig. 3).

After that, point c is found on line-2. To do this, the distance ab is multiplied by a factor of 4.17. In the absence of deformation, point c should correspond to the anterior edge of the 1st metatarsal bone (Fig.

4). In the presence of deformation, point c will determine the degree of correction for accurately planning the correction of deformation (Fig. 5).

It should be noted that the intersection of the axis of the first metatarsal bone and line 2 is the peak of deformation d (Fig. 6). At this level, it is most beneficial to perform corrective osteotomy. For accurate correction of deformation, it is necessary that point c ¹ (intersection of axis 1 of the metatarsal bone with its articular surface) coincides with point c (Fig. 7).

In FIG. 5-7 schematically shows the application of the claimed method with a deformed foot.

To obtain the coefficient values (the angle at which lines 1 and 2 intersect is 24 °; the ratio of the distance from the intersection point (b) to the front edge of the head of the first metatarsal bone (c) to the distance between the anterior and posterior articular points of the ram block (a and b), is 4.17) were analyzed 64 radiographs of undeformed feet of people aged 23 to 64 years. All radiographs were performed with a load in the lateral projection.

The data obtained allowed us to develop a new method of analysis and planning of correction of deformations of the middle part of the foot in the sagittal plane.

The claimed invention was tested on the basis of the medical faculty at St. Petersburg State University. Below are examples of implementation with reference to the explanatory drawings.

Example 1

The explanation in FIG. 8-12. Patient T., 21 years old. Complaints of violation of the back flexion of the right foot, violation of the support ability of the right n / limb, the inability to wear shoes. On the x-ray of the right foot (Fig. 8) there is an equinus installation due to deformation of the talus, subtalar joint and tarsal joints (in Shopar joint). Anamnestically: central neuropathy (cerebral palsy) of the peroneal nerve of the right tibia from birth with the gradual development of foot deformity with an equinus installation. Diagnosis: central neuropathy of the peroneal nerve of the right lower leg. Deformation of the talus. Equinus installation of the right foot at the level of the ankle subtalar and Shoparov joints. During planning, the equine setting of the middle section was revealed (Fig. 9, 10). Conducted planning correction (Fig. 11). During the operation, partial achillo- and aponeurotomy were performed. Fixation of the foot and lower leg in an external fixation apparatus (Ortho-SUV). In the postoperative period, a metered correction was performed. At the end of the correction, a modular transformation of the apparatus was performed (Fig. 12).

Example 2

The explanation in FIG. 13-16. Patient L., 67 years old. Hospitalization in RNIITO in September 2016. Diagnosis: post-traumatic combined deformity of the left foot. Arthrodesis of the left ankle joint with metal osteosynthesis with an intramedullary nail with blocking from 2014. According to the lateral radiograph in FIG. 14, 15 the planning of the correction of the middle section is carried out. Operation: removal of the intramedullary shaft, V-shaped osteotomy and fixation in AVF. Dosed correction was performed in the Ortho-SUV apparatus. In FIG. 16 end of correction, modular transformation of the apparatus for a further period of consolidation.

Example 3

The explanation in FIG. 17-20. Patient K., 34 years old. Hospitalization in RNIITO in May 2012. Diagnosis: dysplasia of the bones of the right foot. According to the lateral radiograph in FIG. 18, 19 the planning of the correction of the middle section. Operation: V-shaped osteotomy and fixation in AVF. A metered correction was made in the Ilizarov apparatus. In FIG. 20 end of correction.

Feasibility study of the claimed invention consists in increasing the information content and accuracy of the diagnosis of deformation of the middle part of the foot, reducing the duration of the study and reducing its cost, expanding the indications for its use, as well as simplifying

- 2 034388 interpretation of the results, which makes it possible to use it at the prehospital stage of the examination. The proposed change in view on the diagnosis of deformities of the middle part of the foot, the reduction of the study time will allow the method to be used as a screening method and also significantly reduce the cost of diagnosis.

The high significance of the claimed invention lies in the great relevance and relevance for the broad masses of the population (as can be seen from the above examples, its use is important for the treatment of different age categories), which was made possible by taking into account complex information (the totality of data taken into account for each specific case of a patient’s disease gives comprehensive information for the implementation of high-quality, effective and most comprehensive planning of surgical correction).

List of used literature.

1) Lamm B.M., Stasko P.A., Gesheff M.G., Bhave A. J. Normal Foot and Ankle Radiographic Angles, Measurements, and Reference Points. Foot Ankle Surg., 2016 Sep-Oct; 55 (5): 991-8. doi: 10.1053 / j.jfas.2016.05.05.005. Epub 2016 Jun 16.

2) Lindenbrathen L.D. Methodology for the study of x-rays. - M.: Medicine, 1971.-351 p.

3) Kirienko A., Villa A., Calhoun J.H. Ilizarov Technique for Complex Foot and Ankle Deformities, Marcel Dekker, New York, 2004, pp. 98-103.

4) Patent RU 2576087, Zagorodni N.V., Tikhonov O.A., Protsko V.G., Chernyshev A.A., Oleinik A.V. A method for determining the degree of flat-valgus deformity of the foot (prototype).

Claims (1)

A method for determining the degree of deformation of the foot at the level of the middle section for preoperative planning of surgical correction, which consists in obtaining radiographs of the foot with a load, determining reference lines and angles of the middle section of the foot, the totality of which determines the degree of deformation of the foot, characterized in that the vertex is determined on the radiograph deformations and reference lines and angles of the middle part of the foot by building on the obtained x-ray of the foot with a load in the lateral projection of the articular line the surface of the talus block (ab), from the rear point of the articular surface of the talus block (b), draw a line anteriorly and downward at an angle of 24 ° and determine the anatomical position of the head of the first metatarsal bone using the formula bc = ab x 4.17, and then determine the degree deformations by the value of the angle between the mechanical axis of the first metatarsal bone and the bc line and by its value determine the localization of surgical intervention and the volume of the planned surgical correction.