RU2779369C2 - Method for replacing a radius joint defect with an individual 3d implant - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: inventions group relates to medicine, namely to oncology, traumatology and reconstructive surgery, and can be used when replacing a radiocarpal joint with restoring its functions. A 3D implant is made by 3D printing in the form of a wrist implant, consisting of carpal and radial components connected by a hinge joint. At the same time, the articulated joint provides flexion-extensor movements within +-90 degrees, and radial and ulnar abduction - within +-15 degrees. When replacing a defect of the wrist joint, a fitting is performed with the installation of a product template. Then, the radial component of the device is installed in the canal of the radial bone, and the carpal component is fixed with screws, after which the implant is assembled.

EFFECT: inventions group provides the possibility of flexion-extensor movements in the wrist joint, reduction of preparation time and total operation time, reduction of the volume of surgical trauma, reduction of the implementation time for a personalized approach in the treatment of patients with defects of the radiocarpal joint through the use of additive technologies, preoperative planning and template creation.

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Description

SUBSTANCE: invention relates to medicine and can be used in oncology, traumatology, reconstructive surgery when replacing a wrist joint with restoring its functions.

The wrist joint is complex in terms of the number of bones involved in it, and in terms of the shape of the articular surfaces it belongs to ellipsoidal joints with two axes of rotation (sagittal and frontal). Even minor changes in this joint cause functional limitations and a deterioration in the quality of life. To address this issue, there is a certain arsenal of methods of orthopedic surgical care. However, unfortunately, if it is impossible to save the joint, the most common method is arthrodesis of the wrist joint. Arthrodesis of any joint is the end point of surgical care. It is for this reason that doctors around the world are trying to find a way to maintain or increase the range of motion in the joint.

Wrist arthroplasty is still a relatively unexplored area. The complexity of motions in the wrist makes it much more difficult to imitate physiological movements with the help of an endoprosthesis, and the attachment of the carpal component is difficult due to the small size of the carpal bones. Known wrist endoprostheses often exhibit similar failure patterns and a limited lifetime of the prosthesis. The most common failures include prosthesis loosening and fractures and dislocations. Loosening can occur on both the carpal component and the radial component. The reasons for the loosening of the prosthesis are varied. In addition to infections and technical defects during implantation (e.g. incorrect positioning/orientation), the different mechanical behavior of the implant and bone, complex motion patterns and small attachment surfaces play a decisive role. In addition, a rigid implant absorbs forces acting on the bone, which can lead to remodeling processes or osteoporosis and thus loosening of the implant. These effects are enhanced by the use of standardized prostheses, since their predetermined size ratios are often incompatible with the actual geometric ratios in the patient's wrist. An additional factor that often arises in connection with the negative aspects of carpal endoprosthesis care is the limited range of motion due to the inconsistency of the articular surfaces of the endoprosthesis wrist with the initial natural articular surfaces of the patient to be treated. Due to the various types of failures, the life span of wrist endoprostheses that are currently state of the art are often severely limited.

Known endoprosthesis wrist (DE 102019114314 A1, Germany, 03.12.2020). The endoprosthesis includes a radius (beam) component, a rod for fixation in the radius, head and first articular surface, which is located on the distal side of the head, and a carpal component with the proximal side of the wrist, the distal side of the wrist and the second articular surface, which is formed. on the proximal side of the wrist, and the surface of the joint of the radial component has a groove-like shape to partially cover the bones of the wrist.

Known endoprosthesis of the wrist Remotion from the manufacturer Stryker Corporation (WO 2008/024853 A2). A total wrist endoprosthesis with a radial component is fixed with a nail and a carpal component. The radial component and the carpal component have an articular surface that interacts with the articular surface of the other component and takes over the joint function of the patient's natural wrist.

Common to both endoprostheses of the wrist is that the wrist component is fixed inside the bones of the patient's wrist using screws and pins. To do this, the bones of the first carpal row are completely or partially removed and the marrowy spaces in the region of the anchor pins and screws are largely opened. The disadvantage of known endoprostheses is that the result is a serious invasive injury, which complicates the subsequent treatment and causes a long healing process. In addition, if the prosthesis fails, there may not be enough bone material to restore the prosthesis.

Also known are wrist endoprostheses that are partial prostheses and are not suitable for the treatment of serious injuries and / or diseases (including cancer) of the entire human carpal apparatus (WO 2018/086765 A1 and WO 2018/053431 A1).

A process for the manufacture of prostheses is known (US 2017/0360578 A1). The invention is based on the fact that the gutter-shaped wrist component provides a particularly simple and secure fixation of the wrist component on the bones of the patient's wrist. In addition, bone resections can be minimized, or ideally avoided entirely, by using a trough-shaped carpal component. The wrist component is a component of the wrist endoprosthesis according to the invention, designed to be attached to the bones of the patient's wrist. The shape of the groove allows the carpal component to at least partially be fixed through one or more of the bones of the wrist of the patient to be treated, so that the bones of the wrist are partially located within the carpal component. If one or more carpal bones are located within the carpal component, they are surrounded by the carpal component on at least three sides. The bones of the wrist are preferably surrounded on the palmar, dorsal and proximal sides of the wrist by a groove-like carpal component. A wrist endoprosthesis designed in this way can provide a longer life than those known in the art.

Known modular articular prosthesis of the wrist (CZ 21982U1, 04/06/2011). The technical solution relates to a modular articulated design, including a carpal and radial component, which in turn consists of a plastic insert located in the articulated cup, and a ball joint with a head and an anchor rod that prevents rotation on the carpal side.

The function of the wrist joint and its axial location are critical to the grip of the hand. Post-traumatic, arthritic, but especially rheumatic deformities severely limit this ability. Painful, axially deformed and unstable wrists are indicated for surgical treatment, in which total replacement also plays an important role. The multiplicity of articular surfaces, the complex biomechanics of the wrist, and the requirements for functional mobility in terms of flexion/extension, pronation/supination create many challenges for joint replacement.

The peculiarity of the wrist replacement is that there is a certain subtlety of the bone structures in which the implant must be fixed. Ultimately, this is the distal part of the radius and the diaphysis of the metacarpal bone. bones of the distal wrist. Partial carpectomy, i.e. resection and removal of almost all proximal carpal bones, together with partial resection of the radius of the joint and complete resection of the head of the ulna, is an integral part of all methods of total arthroplasty.

A wrist prosthesis is also known (WO 2017165727, 07/26/2018). The wrist prosthesis of the present invention replaces the proximal carpal row and restores wrist function using three separate components - the carpal component, the lunate component, and the radial component. When assembled, the prosthesis is attached to the radius of the forearm and trapezium (optional), capitate, and third metacarpal bones of the hand. The three assembled prosthesis components provide a wide range of motion between the radial and carpal components. The radial component of the prosthetic wrist includes a rod at its proximal end for insertion and attachment to the radius and an approximately hemispherical concave bearing surface at its distal end for engagement with the lunate component. The carpal component of the prosthetic wrist contains a rod and a locating pin at its distal end for attachment to the head and third metacarpal bone, as well as a ball end at its proximal end for engagement with the semilunar component. Some embodiments of the present invention further include holes for attaching the wrist component to the trapezius. Between the radial and carpal components is the lunate component, which on the side facing the radial edge consists of a hemisphere that closely matches the geometry of the radial component. The carpal side of the lunate component is composed of a cavity that exactly matches the geometry of the ball end of the carpal component and allows the lunate component to "snap" onto the ball end of the carpal component. The center of the spherical cavity in the crescent is slightly offset proximally from the center of the outer spherical surface of the crescent to provide a "self-centering" characteristic for component placement. The crescent component is made from a strong yet resilient material such as ultra-high molecular weight polyethylene ("UHMWPE"). The carpal and radial components are made from a high quality surgical grade metal alloy such as cobalt chromium molybdenum (CoCrMo), well known for biomedical applications such as total joint replacement. The use of a polyethylene crescent component in conjunction with carpal and radial CoCrMo components provides the following advantages: (a) avoidance of metal-to-metal friction between moving parts and the known complications associated therewith; (b) self-lubrication of the inner and outer surfaces of the semilunar component; (c) cushioning and shock absorption of the prosthesis; and (d) exceptional durability.

Also known is a method for performing wrist reconstruction using a wrist implant (US9233004B2, 01/12/2016). The wrist implant requires minimal resection of the distal radius and preserves the sigmoid and articulation with the head of the distal ulna. The wrist implant includes a radial part, a carpal part and a carpal ball, includes a primary articulation and a secondary rotational articulation. The primary articulation occurs between the radial part and the carpal ball. Secondary articulation occurs between the carpal ball and carpal part.

A type of 3D-printed prosthesis for the treatment of a tumor of the distal radius and a manufacturing method (CN 108245288 A, 07/06/2018) the structure has a fixed part, the other end has a connecting part, the structure is made of polyetherketone or its derivatives, the body surface is provided with a porous bionic bone trabecula and opens a perforated hole for attaching the ontology in the marginal position. Using polyester-ether-ketone or its derivatives, its modulus of elasticity is more in line with the natural skeleton of the human body, relieves the stress of the shielding problem, a certain shock-absorbing effect is reproduced during exercise, the abrasion of other bones of the implant material used is reduced, in addition, the material is a non-metallic material, reduced allergy, a toxicity problem caused by metal corrosion and the possibility of metal.

The closest (prototype) is an individual prosthesis of the radius (CN 111358598 A, 07/03/2020). The invention relates to a matched personalized prosthesis of the radius, which contains a distal articular surface, a body of the radius, a broach of the radius and a locking bolt, while the blocking structure between the body of the radius and the firmware of the radius is a sliding structure with a clamping groove, and the clamping groove design of the slider can prevent axial movement and rotation of the radius body and radius broach after locking the lock bolt; the radial body and the connection surface at the far end are fixed by the internal structure of the buckle. The assembled personalized prosthesis of the radius is produced in the mode of assembly and enlargement of the material, and can be prepared in advance with different specifications, and the specifications are collected, so that a standard series is formed in the personalized prosthesis. The needs of real patients for various prostheses are met through a range of designs and pre-preparation, as well as a combination of various specifications. Thus, realizing personalized and serial prostheses and reducing the production time of prostheses while respecting personalization.

The disadvantages of the above endoprostheses and methods for reconstruction of the wrist joint are:

- limited range of motion

- easy to move

- place too much stress on the bones, leading to failure or fractures,

- cause complications such as infections, and premature wear, requiring additional operations during the patient's life. In addition, the methods currently used to implant such prosthetic wrists often result in poorly aligned joints and poor joint function.

Accordingly, there is a current need for a wrist prosthesis and implantation methods that provide the patient with a range of motion approximating that of a healthy wrist, with long-term implant survival, provide adequate support for the remaining bones of the hand and forearm, and avoid many of the disadvantages of existing wrist prostheses.

Wrist implants typically include two components, namely a distal component (or wrist component) and a proximal component (or radial component). Wrist implants include a somewhat elliptical convex distal component that articulates with a similarly shaped concave radial component. While these implants readily allow rotation about two major orthogonal axes, coinciding with the classically and anatomically defined flexion-extension and radial deflection wrist movements, these implants do not easily allow wrist movements inclined to these orthogonal axes.

The technical solution is the development a method for reconstruction of the wrist joint in case of defects of the radius and the manufacture of an individually designed device for the reconstruction of segmental defects of the radius according to anthropometric data, ensuring optimal anatomical compliance with the geometry of the defect, providing flexion-extension movements, reducing the preparation time and the total time of the operation, reducing the volume of the surgical injuries, shortening the implementation of a personalized approach in the treatment of patients with defects of the wrist joint.

A feature of the proposed method is that a 3-D implant is made by 3D printing by direct laser sintering from titanium powder based on the results of computed tomography of the areas of the bone tissue of the wrist and using the obtained scans, in the form of a wrist implant, consisting of carpal and radial components connected articulated between each other, and the wrist component contains a platform with two holes for screws, on one side of the platform there is a ring element containing an insert made of UHMWPE along the inner contour of the ring, and the outer part of the ring element has a smooth polished articulation surface, on the other side of the platform there is a leg, and the radial component consists of a leg and a detachable element with holes, including a base and a sleeve, between which the annular element of the hand component is fixed, during assembly, the opening of the annular element is combined with the detachable element of the radial about the component and fix it with a lock.

When replacing a defect in the wrist joint with an individual 3-D implant, a plastic try-in template is used to determine the boundary of the resection of sections of the bone tissue of the wrist, try-on is performed with the installation of the product template, for this, a guide sleeve is installed to drill a hole for the central pin, a hole with a diameter of 5 mm is made through the guide on depth of 21 mm, then the template of the carpal component is placed with a pin on the template of the product of the radial component and the template is tried on, the axis of fixation of the template of the carpal component is removed and the radial component of the device is installed in the canal of the radius, and the carpal component is fixed with screws, after which the implant is assembled, installed into the base of the ray component and connect the annular element of the hand component with the detachable element of the ray component, install a limiting sleeve, pass through the hole of the annular element of the axis and install the lock.

At the same time, the articulation provides flexion-extension movements within +-90 degrees, and radial and ulnar abduction - within +-15 degrees.

The invention is illustrated by a detailed description, a clinical example and illustrations, which show:

Figure 1 - Scheme of the defect of the wrist joint: a) the area of resection of the defect is highlighted in red; b) 18 - a plastic fitting template for determining the boundaries of the resection of areas of the bone tissue of the wrist.

Fig. 2 - Carpal component: a) in lateral projection: 1 - carpal component; 2- leg of the carpal component; 3- ring element for binding the radial and carpal components and installing the lock; 4 - liner made of UHMWPE (yellow); b) in direct projection: 5-holes for fixing screws.

Fig. 3 - Ray component: 6 - beam component; 7 - leg of the beam component, 8 - detachable element of the beam component; 9 - holes for connection with the annular element of the brush component.

Fig. 4 - Swivel joint: a) 10 - swivel joint; 11 - a lock that fixes the carpal and radial components; 12- key; b) 3 - annular element of the carpal component; 13 - screws; 14 - base of the detachable element of the beam component, made of UHMW; 15 - bushing of the detachable element of the beam component, made of UHMW; 9 - holes for connection with the annular element of the hand component; c) 16-axis.

Fig. 5 - Assembling the fitting template of the device: 1 - hand component; 6 - beam component; 7 - leg of the beam component; 11- lock.

Fig. 6 - Scheme of marking the line of resection of the hand and radius: lines in blue - the axis of the pin is indicated; red color - resection line.

Fig. 7 - Installation of the guide bush for drilling a hole for the central pin: 17 - Guide bush for drilling a hole for the leg of the hand component made of polyamide.

Fig. 8 - Location of the template of the hand component with a pin on the template of the product of the beam component, trying on the product: 1 - hand component; 6 - beam component, 7 - leg of the beam component; 11 - lock.

Fig.9 - Installation of the carpal component of the device: 1 - carpal component (with an outer smooth polished articulation surface); 3- ring element (for binding the radial and carpal components and installing the lock); 4 - insert; 13- screws.

Fig. 10 - photo: appearance of device templates.

Fig.11 - photo: the appearance of the components of the finished device.

Fig. 12 - The result of radiographic examination after implantation.

The method is carried out as follows.

Before surgery, at the first stage, the localization of the alleged defect of the wrist joint is determined. In the computer environment, the resection of sections of the bone tissue of the wrist is planned, the templates of the device and templates for resection of the bone tissue are designed and modeled, the shape and size of the bone defect are determined. Perform three-dimensional computer simulation of the required geometry of the template for resection (Fig.1 a, b) and fitting template device (Fig.5), corresponding to the alleged defect of the wrist joint.

The necessary structure, graft geometry, fixing holes are modeled.

After planning, the device is 3D printed using a 3D printer by direct laser sintering by titanium powder 3D printing. As a result, the device is shaped to approximate the anatomical shape of the patient's wrist before the onset of the tumor. Using 3D printing technology, based on a three-dimensional model of a patient's bone tissue defect, plastic device templates (Fig. 5, Fig. 8), resection templates 18 (Fig. 1 b) are made. Template material - biocompatible plastic.

The base 14 and the sleeve 15 (Fig. 4b) of the detachable element of the beam component, as well as the insert 4 of the annular element 3 of the brush components 1 (Fig. 2a) and the lock 11 (Fig. 5) are made of ultra-high molecular weight polyethylene by milling.

The structure is designed individually for a specific defect of the patient, the fasteners are carried out in the direction of the most pronounced bone mass, specified during the design.

Prior to the operation, an approximate device template is assembled (Fig. 5), the resection site, the position of the resection lines are determined, and the resection is marked for its implementation (Fig. 1 a, b; Fig. 6), focusing on the product template and dimensions. The markup begins with the definition of the resection line.

During the operation, access is made to the segment of the radius affected by the tumor. After resection of the radius and hand bones, fitting is performed with the installation of the product template (Fig. 5).

The implant is made after design and coordination with surgeons. Try-in is carried out during the surgical intervention in order to plan all levels of resection and to make sure that the main implant is placed correctly.

An individual 3-D wrist joint implant is made from titanium powder. The implant consists of a carpal 1 and a radial component 6 (Figure 2 a, b, Figure 3, Figure 11), which are interconnected by a swivel 10 (Figure 4 a, b c).

Swivel joint 10 (Fig. 4 a, b, c) includes: a lock 11 that fixes the carpal and radial components, a key 12, an annular element 3 of the carpal component 1, a base 14 of a detachable element of the radial component 6, made of UHMWPE, a sleeve 15 , made of UHMP and holes 9 for connection with the annular element 3 of the wrist component 1, as well as the 16-axis. At the same time, the articulation provides flexion-extension movements within +-90 degrees, and radial and ulnar abduction - within +-15 degrees.

The wrist component 1 contains a platform with two holes 5 for screws, on one side of the platform there is a ring element 3 containing an insert 4 made of UHMWPE along the inner contour of the ring, and the outer part of the ring element has a smooth polished articulation surface, on the other side of the platform there is a leg 2 (Fig. 2 a, b).

The beam component 6 consists of a leg 7 and a detachable element 8 with holes 9 (Figure 3), including the base 14 and the sleeve 15 (Figure 4 b), between which the annular element 3 of the wrist component 1 is fixed (Figure 2 a, b) .

When assembling the product, the holes 9 of the detachable element 8 of the beam component 6 (Fig. 4 a-b) are aligned with the annular element 3 of the wrist component 1 and fixed with a lock 11 (Fig. 4 a-b, Fig. 5).

Then install the guide sleeve 17 (Fig.7) to drill holes for the Central pin. Drill a hole with a diameter of 5 mm to a depth of 21 mm. Next, a template of the hand component 1 is placed with a pin on the product template of the beam component 6 and the template is tried on (Fig. 8).

Axis 16 (Fig. 4c) fixing the template of the carpal component 1 is removed and the radial component 6 of the device is installed in the canal of the radius, and the carpal component 1 is fixed with screws 13 (Fig.9).

Carry out the assembly of the product as follows.

In the beam component 6 (Figure 3) set the base 14 (Figure 4 b). The annular element 3 of the wrist component 1 is connected to the detachable element 8 of the beam component 6 (Fig. 2-3), limiting sleeves 15 (Fig. 4b) are installed, the axis 16 (Fig. 4 c) is passed through the annular element 3 and the lock is installed with the key 12 11 (Fig. 4a). The carpal component 1 is installed and fixed through holes 5 (Figure 2 b) with two screws 13 (Figure 4 b). After installing the try-in template of the forearm component, a final resection is performed. Install the beam component 6 (Fig. 3). The carpal 1 and radial 6 components of the endoprosthesis are interconnected by a hinged lock 11 using a key 12 (Fig. 4 a) and motion tests are performed.

It is important not to damage the polished surface of the product parts during assembly.

Clinical example of using a 3-D implant.

Patient Z., aged 37, diagnosed with C40.0 Giant cell tumor of the lower third of the right radius. 3 courses of denasumab treatment. There are no associated diseases.

Anamnesis: Since August 2020, he notes the presence of a tumor-like formation in the area of the right wrist joint, which gradually increased in size. I went to the doctor for the first time in September 2020 and was referred to an oncologist. Trepan biopsy was performed only in December 2020. Conclusion - Giant cell tumor. February 2021 turned to the MRNC them. A.F. Tsyba. Excluded hyperparathyroidism. Produced repeated biopsy education. Conclusion on the morphological study dated February 28, 2021: morphological picture of a giant cell tumor. According to the CT scan dated February 17, 21, there is swelling and destruction of the lower third of the radius, including the distal end of the bone, without destruction of the scaphoid and lunate bones. The total length of the destruction area is 7-8 cm. At the level of the destruction area, a tumor formation of a heterogeneous structure and density is determined, with necrosis in the thickness, intensively accumulating RVC, maximum transverse dimensions of 9.5x8 cm, up to 10 cm long. There is a thinning of the cortical layer at the distal end ulna (closer to the head of the bone), for 10 mm, at the level of the described tumor formation. The main vessels of the forearm, at the level of the described tumor formation, are not differentiated. At the place of residence, 3 courses of treatment with denosumab were carried out. During the control examination, there is a positive trend in the form of compaction of the tumor component.

Surgical treatment: 07/09/2021 Resection of the distal segment of the right radius with endoprosthesis of the radiocarpal joint

Operation progress:

Skin incision along the dorsal surface of the distal part of the right forearm. Bluntly and sharply divorced soft tissue over the tumor. The extensor tendons of the fingers were abducted. Produced resection of the radius for 12 cm from the articular surface. Further isolation of the tumor was carried out in stages from the proximal and distal ends of the tumor. The capsule of the wrist joint was dissected and a fragment of the radius with a tumor was removed as a single block. Hemostasis. The lines of resection of the bones of the wrist and radius are marked, according to the fitting templates. Produced resection of the bones of the wrist using templates of the device (Fig.11). A try-on template was installed on the wrist, holes were drilled for the installation of the final carpal component of the endoprosthesis. The carpal component is installed and fixed with two screws. After installing the try-in template of the forearm component, the final resection was controlled and performed. Installed component of the forearm (Fig.12). The carpal and radial components of the endoprosthesis are interconnected by a hinged lock.

Produced tests for movement. Vacuum drain. Seams on soft tissues with fixation, if possible, to the endoprosthesis. Stitches on the skin. Aseptic bandage. After 4 days, postoperative X-ray control of the installation of an individual implant was performed. According to the X-ray examination after the operation, the position of the endoprosthesis is correct.

The proposed reconstruction method using a radiocarpal joint endoprosthesis allows:

- for the patient to perform wrist movements inclined to orthogonal axes;

- significantly improve and simplify the use of the endoprosthesis of the wrist joint;

- to reduce the time of implantation due to accurate preoperative planning and creation of templates.

Claims (3)

Fig. 1. An individual 3D implant to replace a tumor-affected area of the wrist joint, made by 3D printing by direct laser sintering from titanium powder based on the results of computed tomography of the bone tissue of the wrist and using the obtained scans, in the form of a wrist implant, consisting of a carpal and of the radial components interconnected by a swivel, providing flexion-extension movements and radial and ulnar abduction, and the carpal component contains a platform with two holes for screws, on one side of the platform there is an annular element containing an insert made of ultra-high molecular weight polyethylene (UHMWPE) along the inner contour of the ring ), and the outer part of the ring element has a smooth polished articulation surface, on the other side of the platform there is a leg, and the beam component consists of a leg and a detachable element with holes, including a base and a sleeve made of UHMP, between which The ring element of the hand component is fixed with an eye, during assembly, the hole of the ring element is combined with the detachable element of the beam component and fixed with a lock made of UHMP. 2. A method for replacing a defect in the wrist joint with an individual 3D implant according to claim 1, characterized in that a plastic try-in template is used to determine the boundary of the resection of sections of the bone tissue of the wrist, a try-in is performed with the installation of the product template, for this a guide sleeve is installed to drill a hole under the central pin, a hole with a diameter of 5 mm is made through the guide to a depth of 21 mm, then a template of the carpal component with a pin is placed on the template of the product of the radial component and the template is tried on, the fixation axis of the template of the carpal component is removed and the radial component of the device is installed in the canal of the radius, and the carpal component are fixed with screws, after which the implant is assembled, the base is installed in the ray component and the annular element of the carpal component is connected to the detachable element of the ray component, the limiting sleeve is installed, the axis is passed through the hole of the annular element of the axis and the lock is installed. 3. An individual 3D implant according to claim 1, characterized in that the articulation provides flexion and extension movements within 90 degrees, respectively, as well as radial and ulnar abduction within 15 degrees, respectively.

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