RU207672U1 - Fixation device for osteosynthesis of the greater trochanter - Google Patents

Abstract

The utility model relates to medical technology, namely to traumatology and orthopedics, and can be used for internal fixation of the greater trochanter of the femur. The technical result of the utility model consists in reliable fixation of fragments of the proximal femur after two-level osteotomies during hip arthroplasty in complex deformities of the proximal femur. The result of the utility model is achieved due to the fact that the fixator includes an extra-bone part with lugs extended beyond the outer contour of the plate, in which combined holes for the introduction of screws are made, as well as a trident fork at the proximal end, and the immersed parts of the teeth are parallel between itself, according to the utility model, is made of a plastic metal alloy; the bone part is made straight; the immersed parts of the teeth are oriented at an angle of 60 ° relative to the bone part.

Description

The utility model relates to medical technology, namely to traumatology and orthopedics, and can be used for internal fixation of the greater trochanter of the femur.

In the 70-90s of the twentieth century in domestic orthopedics, two-level osteotomies of the proximal femur were widely used for surgical correction of hip dysplasia and hip subluxation, less often for acquired deformities of the proximal femur (RU2355347; RU2475204), in which the process of degeneration slowed down, but did not exclude the appearance of indications for hip replacement at the age of 40-50. The shape of the proximal femur after such osteotomies excluded the performance of standard arthroplasty, since there was no possibility of correct insertion of the straight stem of the femoral component into the canal with two large bends. Insertion of the stem into such a canal usually requires a two-level osteotomy, in which the proximal level involves cutting off a long fragment that includes the greater trochanter. (Bliznyukov, V.V. Hip arthroplasty in patients with deformities of the femur. Dissertation, Candidate of Medical Sciences. - SPb., 2015. - 162 p.).

Individual differences in the shape of the proximal femur between such patients are almost infinite, which does not allow creating a universal fixator that would ensure the stability of a two-level osteotomy in hip arthroplasty with multiplanar and, most importantly, exclusively individual deformities of the proximal femur. This required the creation of a fixator for periprosthetic fixation of the proximal femur, suitable for intraoperative fitting (modeling the shape of the implant using multiplanar bending), which would be feasible during arthroplasty for terminal arthrosis against the background of iatrogenic two-level deformity of the proximal femur.

Closest to the claimed device is a plate designed for internal fixation of the greater trochanter of the femur (RU2681245). With the help of this plate, the trochanter is fixed to the femur after osteotomy of the proximal section, periprosthetic fractures, as well as pseudoarthrosis of this localization.

However, this device has a factory pre-bend based on the normal anatomy of the proximal femur and is made of a material that does not allow modeling (deforming) the retainer according to the shape of the proximal femur in the case of correction of pronounced multiplanar complex deformities.

The task of the utility model is to develop a device that allows to reliably fix the greater trochanter to the proximal femur, taking into account the individual characteristics of the patient in each specific clinical case due to the possibility of intraoperative modeling of the device.

The technical result of the utility model is to ensure reliable stability of the osteosynthesis of the osteotomized fragments during hip arthroplasty with complex deformities of the proximal femur.

The result of the utility model is achieved due to the fact that the retainer includes an extra-bone part with lugs extended beyond the outer contour of the plate, in which combined holes for guiding screws are made, as well as a trident fork at the proximal end, and the immersed parts of the teeth are parallel to each other, according to the utility model , made of ductile metal alloy; the bone part is made straight; the immersed parts of the teeth are oriented at an angle of 60 ° relative to the bone part.

The illustrations show

FIG. 1. Fixation of the greater trochanter (top view), where: 1 - bone part; 2 - lugs; 3 - teeth; 4 - combined holes.

FIG. 2. The same, bottom view, where 1 - bone part; 2 - lugs; 3 - teeth; 4 - combined holes.

FIG. 3. The same, side view. 1 - bone part; 2 - lugs; 3 - teeth; 4 - combined hole.

FIG. 4. Clinical example of planning a corrective osteotomy of the femur with complex deformity (A - preoperative planning on the radiograph of the hip joint in frontal projection; B - skigram of the proximal femur), where 6 is the greater trochanter; 8 - femur; 9 - osteotomy lines.

FIG. 5. Modeling the device along the contour of the proximal femur (A - factory view of this utility model; B - the proximal femur formed after osteotomies; C - the proposed device after modeling), where 3 - teeth; 6 - large spit; 8 - femur.

FIG. 6. An example of using a utility model for fixing the proximal femur after correcting a complex deformity during total arthroplasty: 3 - teeth; 5 - screws; 6 - large spit; 7 - adjacent compact layer; 8 - femur; 10 - stem of the endoprosthesis.

The device is made of a ductile metal alloy approved for use in traumatology and orthopedics. The device (Fig. 1-3) consists of an extra-bone part 1 with lugs 2 and teeth 3 at the proximal end of the extra-bone part 1. The teeth 3 are parallel to each other and oriented at an angle of 60 ° to the extra-bone part 1 (Fig. 3). The bone part 1 in the lugs 2 contains combined holes 4 for screws 5 (Fig. 1, 2, 3, 5, 6) with the possibility of introducing screws 5 through the greater trochanter 6 and the adjacent compact layer 7 of the femur 8. All lugs 2 are made with combined holes 4 with the possibility of using both cortical and angle-stable screws 5 with a permissible deviation of the axis of the screws 5 in the horizontal plane up to 30 °.

The device is used as follows. According to preoperative planning, after surgical access and mobilization of the proximal femur 8, osteotomies are performed along lines 9 (Fig. 4) at the level of the greater trochanter 6. Next, the greater trochanter 6 is compared with the femur 8, after which the device is modeled along the contour and placed on the femur bone 8, orienting the ends of the immersed part of the teeth 3 to the greater trochanter 6. The teeth 3 are immersed until firmly seated in the greater trochanter 6. After that, the entire device with the large trochanter 6 impaled on the teeth 3 is fixed to the femur 8 by introducing screws 5 through the holes 4 of the lugs 2 extra bone parts 1, which 5 can come out through the adjacent compact layer 7 on the opposite surface of the femur 8, bypassing the endoprosthesis stem 10.

When stable internal fixation is achieved, the wound is sutured in layers. Immobilization in the postoperative period is not used. The reliability of fixation of a fragment of the greater trochanter is sufficient for active movements, which begin in the early postoperative period before suture removal.

The device allows

fix the fragments of the femur after the correction of complex deformities;

ensure reliable fixation of a fragment of the greater trochanter, taking into account the individual anatomical features of the proximal femur;

perform osteosynthesis of both fractures of the greater trochanter and periprosthetic hip fractures, subject to the availability of standard sizes along the length.

Claims (1)

Fixation device for osteosynthesis of osteotomized fragments of the femur during hip arthroplasty with complex deformities of the proximal femur, made of a plastic metal alloy with the possibility of modeling along the contour of the proximal femur and including a straight extraosseous part with lugs outside the outer contour of the plate, in which combined holes for screws are made with the possibility of screws bypassing the stem of the endoprosthesis, as well as a trident fork at the proximal end, and the immersed parts of the teeth are parallel to each other and oriented at an angle of 60 ° relative to the bony part.

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