RU2537215C1 - Osteosynthesis device for fractures of lower pole of patellas - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: osteosynthesis device for fractures of the lower pole of the patella comprises a plate with branches curved after the lower pole of the patella. The plate is made of a shape-memory titanium nickelide alloy, has two upper, two side and two lower branches curved arch-wise after the lower pole of the patella. The upper and side branches have locking legs. The locking legs of the upper branches are bent and directed towards the lower branches. The side branches extend from a base of the upper branches, curved after the side contour of the patella, while their legs are bent towards each other.

EFFECT: invention enables providing the reliable fixation of fragments, performing early therapeutic exercises, forming a central callus that requires no long immobilisation, reduces the length of treatment and improves the outcomes.

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Description

The invention relates to medicine and can be used in traumatology.

Fracture of the lower pole of the patella is most often presented in the form of small hard-to-repair fragments or a single fragment with its own patellar ligament attached to it (transdermal breaks of its own patellar ligament). All fractures of the patella are of an unstable type, as they experience significant effort exerted during movements in the knee joint. With surgical treatment, they require perfect reposition, reliable fixation, early rehabilitation of the limb. The search for reliable osteosynthesis of fractures of the lower pole of the patella led to the creation of a large number of methods.

In widespread practice, due to the difficulties of repositioning fractures of the lower pole of the patella, they resort to partial patelloectomy with subsequent reinsertion of their own patellar ligament. Chaklin, V.D. Injuries and diseases of the knee / V.D. Chucklin // Orthopedics. - M., 1957. - S.645-665.

The main disadvantages of this method of treatment are:

1 - long-term immobilization of the limb up to 6-8 weeks with the development of subsequent hypotrophy of the quadriceps muscle and post-immobilization contracture, requiring long-term rehabilitation;

2 - when removing fragments of the lower pole of the patella, a bone defect is formed that violates the articulation of the patella, resulting in trauma to the underlying articular cartilage with the development of further patellofemoral arthrosis, Goff disease.

Currently, various designs are used for osteosynthesis of patella fractures. Existing metal structures have one or another disadvantage: the inability to compress fragments along the entire fracture line and exclude their rotational displacements, width displacements. This leads to longer immobilization of the limb, long consolidation of the fracture, secondary displacements of fragments, metal structure migration, which result in atrophy of the quadriceps femoris muscle, deforming arthrosis, knee joint contracture, etc.

A device for osteosynthesis (AS USSR N 1152582, class A61B 17/58, publ. 04/30/1985, bull. No. 16), made in the form of a bracket, made of a material with a memory effect. The bracket contains a plate with a hole and arcuately bent legs at the ends, at least one pair of which is bent towards each other. The plate at the location of the hole has an extension. At least one pair of legs is bent in opposite directions.

The design has several disadvantages:

- arcuate curved legs throughout the structure cannot repeat the contours of the patella, therefore, do not create a reliable fixation;

- compression is created due to the work of the legs of the structure and is very weak;

- compression legs, located at an angle of 90 ° to the plane of the structure and cannot create compression over the entire plane of the fracture, which lengthens the consolidation period.

Thus, this device for osteosynthesis can hardly be used for osteosynthesis of patella fractures.

A device with a shape memory for osteosynthesis with transverse fractures of the patella body (RF Patent No. 2117454, class A61B 17/68 // A61L 31/00, publ. 08/20/1998, bull. No. 23) is made in the form of a bracket, the side branches of which arcuately curved in the shape of the side contour of the patella, the distal branches of the branches are oppositely bent at an angle of 65 ° to the plane of the arcuate brackets with the possibility of external overlapping of the fracture line with a loop formed by bending these distal sections of the branches at an angle of 30 °; the fixing legs lie in a plane perpendicular to the longitudinal plane of the rod, are bent at an angle of 70 ° and intersect the plane of said axial rod.

The design has several disadvantages:

- lateral branches, made in the form of arches curved in the form of the lateral contour of the patella of the brackets, do not allow to hold fragments of the lower pole of the patella.

- when carrying out the axial rod, fragments of the lower pole of the patella are additionally damaged.

- in some cases (comminuted fractures), it is additionally necessary to impose a purse string suture according to Libov.

Thus, this device for osteosynthesis can hardly be used for osteosynthesis of fractures of the lower pole of the patella.

Known bone bracket for osteosynthesis, selected as a prototype (M. Krkovic, D. Bombac. Modified pre-curved patellar basket plate, reconstruction of the proper length and position of the patellar ligament. The Knee No. 14; 2007, p. 188- 193), developed for the treatment of comminuted fractures of the distal pole of the Smiljani patella in 1988 in Slovenia. It has the shape of the lower pole of the patella, which allows you to keep the fragmented bone fragments in the correct position. The fibers of the patellar ligament are laid aside, 4 hooks of the plate can be bent so that when fitting in shape and size of the patella, it does not cause damage to the articular surface. The basket plate fixes the main part of the patella fragment with two spongy screws, providing interfragmental compression. Another 2 screws are oblique, creating stability during distraction. Below the fragments, absorbent woven sutures supporting fragments in the bundle are installed through the patellar ligament.

The design has several disadvantages:

- fixing the plate with four screws leads to additional trauma to the proximal patellar fragment, up to its splitting;

- when forming channels for screws, there is a high risk of screwing the tendon elements of the capsule onto a drill or screw, to additional trauma to the peripatellar soft tissues;

- the need for additional absorbent woven sutures through their own ligament of the patella leads to trauma and razvolnenii last;

- the need for reoperation to remove the plate.

Thus, the above design leads to intraoperative (technical) complications, leading to a long period of disability and the need for repeated surgical intervention.

The objective of the invention is to create reliable fixation of fractures of the lower pole of the patella without additional trauma to the proximal fragment of the patella, peripatellar tissues, own patellar ligament;

The task is achieved by the device for osteosynthesis in fractures of the lower pole of the patella, containing a plate with branches, curved in the shape of the lower pole of the patella. The plate is made of an alloy of titanium nickelide with shape memory. The plate has two upper, two lateral and three lower branches, curved arcuate in shape of the lower pole of the patella. The upper and side jaws have locking legs. The fixing legs of the upper branches are bent and directed towards the lower branches. The lateral branches extend from the base of the upper branches, are curved in the shape of the lateral contour of the patella, their legs are bent toward each other.

The novelty of the device:

- The plate is made of titanium nickelide alloy with shape memory. This allows, due to the location of the branches and their legs in different planes and directions, to provide compression over the entire surface of the fracture due to the shape memory effect.

- The plate has two upper, two lateral and three lower branches, curved arcuate in shape of the lower pole of the patella. The shape of the lower branches allows you to keep the fragmented bone fragments in the correct position.

- The upper and side jaws have locking legs. The fixing legs of the upper branches are bent and directed towards the lower branches. The upper and lower branches create axial compression over the entire surface of the fracture due to the shape memory effect, which does not require additional strengthening with absorbent seams or purse string suture.

- The lateral branches extend from the base of the upper branches, are curved in the shape of the lateral contour of the patella, their legs are bent towards each other. The lateral branches of the plate overlap the fracture line on both sides, the formed bends in the shape of the contour of the patella prevent displacement in width and provide tight uniform contact with the surface. The legs of the lateral branches are located in a plane perpendicular to the longitudinal plane of the device and create compression over the entire surface of the fracture.

The set of essential features of the device allows you to:

- to ensure reliable fixation of bone fragments during fractures of the lower pole of the patella, without using screws and drilling a proximal fragment of the patella, peripatellar tissues, own patellar ligament;

- to compress over the entire surface of the fracture, which does not require external immobilization, reduces treatment time;

- minimize trauma to surrounding soft tissues;

- do not carry out repeated surgical intervention in order to remove the device;

- the formation of channels under the legs is enough to carry out using a drill, a spoke and a guide under the control of vision, which allows not to injure the peripatellar soft tissues;

- Proven properties of an alloy of titanium nickelide, such as inertness, non-carcinogenicity, do not remove the device.

The invention is illustrated in FIG. fourteen.

In FIG. 1 is a photograph of a device.

In FIG. 2 shows a blank of a device.

In FIG. 3 is a front view of an installed device.

In FIG. 4 is a side view of an installed device.

The device consists of five branches: three lower ones - 1, two upper ones - 3, fixing legs of the upper branches - 4, fixing legs of the side branches 5. The upper 2 and side branches 3 have fixing legs 4 and 5 in the distal sections , 2 cm long. The fixing legs of the 4 upper branches are bent and directed towards the lower branches 1.

The lower branches 3 are curved arcuate in shape of the lower patella contour.

The lateral branches 3 extend from the base of the upper branches 2, are curved in the shape of the lateral contour of the patella, their legs 5 are bent towards each other.

The design is made of titanium nickelide alloy TN-10, 1.5 mm thick with shape memory effect. For the manufacture of a plate, the preforms of FIG. 2 are heated to 500-600 ° C, for example, on a gas burner (the temperature at which the titanium nickelide alloy becomes ductile and a shape memory effect can be imparted to it). Using kramponovye forceps create the necessary bends of the legs of Figure 1. Then the device is polished in a solution consisting of one part of hydrofluoric (hydrofluoric) acid, four parts of nitric acid and five parts of water.

Osteosynthesis with the help of this bracket is carried out as follows: under general anesthesia in the patient’s position on the back, under the tourniquet, with a parapatelaric incision, the patella is exposed, blood clots are removed, and bone fragments are repositioned. The three lower legs 1 are brought under the lower pole of the patella by piercing their own ligament of the patella, as close as possible to the distal fragments of the lower pole. In the proximal fragment of the patella, two holes are formed for introducing the fixing legs 4 of the upper branches 2 of the device, perpendicular to the frontal plane at an angle of 45 °. On the lateral edges of the proximal patellar fragment, symmetrically, perpendicular to the sagittal plane, two holes are formed for introducing the fixing legs 5 of the lateral branches 3 of the device. The structure is cooled by chloethyl for 2-3 minutes and deformed, the upper 2 and lateral branches 3 are bred, enveloping the fracture line and the proximal patellar fragment. The lower branches 1 are transstendially brought under the lower pole of the patella, the fixing legs 4 and 5 of the upper branches 2 and side branches 3 are inserted into the formed channels. After 30 seconds, due to the contact heating of titanium nickelide, the shape memory effect is manifested, and the design tends to take the originally set shape of FIG. 3, FIG.

In this case, the complex of all branches and fixing legs of the device creates reliable fixation and compression along the entire fracture line. The wound is drained, the integrity of the supporting lateral ligaments of the patella is restored. The wound is sutured tightly. Plaster immobilization. After surgery, external immobilization is required before the seams are removed. An early exercise therapy is prescribed. On average, the period of incapacity for work is reduced by 10 days.

The proposed design for osteosynthesis of patella fractures provides reliable fixation of fragments, early exercise therapy, the formation of endosteal callus, which does not require long-term immobilization, reduces the treatment time for patients, improves outcomes.

This device is used in the Clinic for Traumatology and Orthopedics MBLPU GKB No. 1, Novokuznetsk. Operated with a diagnosis of a fracture of the lower pole of the patella of 3 people. Fusion of the fracture with endosteal callus, no complications, the period of disability decreased by 9-11 days in comparison with the known methods of surgical treatment.

As an example, we cite the following clinical observation.

Patient O., 27 years old, was admitted to the clinic of traumatology and orthopedics MBLPU GKB No. 1 06/23/10 with a diagnosis of Closed comminuted fracture of the lower pole of the left patella with displacement of fragments. Road injury. On radiological images, a multi-fragmented fracture of the lower pole of the patella with displacement of fragments is determined. Considering the nature of the fracture and structural features, an operation was performed under spinal anesthesia on 23.06.10: open reduction, osteosynthesis of a small-fragmented fracture of the lower pole of the left patella with the proposed design with thermomechanical shape memory. On the operation: a cut along Payr, after identifying the fracture site in the upper pole of the proximal patellar fragment, 4 channels were formed for introducing fixing legs. Similarly to the direction of the lower legs, passages are formed in the patellar ligament. After cooling the structure with chloroethyl, the device is shaped into a shape convenient for introducing the fixing legs of the upper and lateral branches into the proximal patellar fragment. Then, the lower branches were introduced through the patellar ligament under the fragments of the lower pole of the patella, the fragments were repositioned and the device was fixed by introducing the fixing legs of the upper and lateral branches into the formed channels. Adaptive U-shaped and interrupted sutures were applied to restore the supporting apparatus. Plaster immobilization was applied for 5 days. In the postoperative period, UHF and a dosed limb load were prescribed on day 3. The gypsum tire was removed, exercise therapy, massage, electrical stimulation of the thigh muscles were prescribed. After 6 weeks, the movement in the knee joint in full, no complaints. After 7 weeks, the patient began to work. The result of the treatment is regarded as good.

Claims (1)

A device for osteosynthesis in case of fractures of the lower pole of the patella, containing a plate with jaws curved in the shape of the lower pole of the patella, characterized in that the plate is made of an alloy of titanium nickelide with shape memory, has two upper, two side and three lower branches, curved in an arcuate shape the lower pole of the patella, the upper and side branches have fixing legs, the fixing legs of the upper branches are bent and directed towards the lower branches, the side branches extend from the base of the upper branches, bent along Orme side contour of the patella, and their legs are bent in a direction towards each other.

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