Rod for intramedullary osteosynthesis of long tubular bones

Abstract

The utility model relates to medicine, specifically to traumatology, orthopedics, and purulent surgery, and can be used in the treatment of fractures of long tubular bones complicated by infectious processes. A rod for intramedullary osteosynthesis of long tubular bones is designed as a curved rod with a roughness Ra in the range of 0.02 to 0.75 μm with holes for transosseous transverse locking with screws. Isolated recesses are formed on the surface of the rod for the placement of a medicinal composition, and the shape of the rod is made anatomically corresponding to the curvature of the bone diaphysis. This achieves an expansion of the arsenal of means for the specified purpose with an increase in the performance characteristics of the rod. 31 clauses, 15 figs., 21 items.

Description

[0001] The utility model relates to medicine, in particular to traumatology and orthopedics and purulent surgery, and can be used in the treatment of fractures of long tubular bones complicated by infectious processes.

[0002] Further in the text, the applicant provides terms that are necessary to facilitate a clear understanding of the essence of the declared materials and to eliminate contradictions and / or controversial interpretations when performing an examination on the merits.

[0003] Intramedullary osteosynthesis is a method of treating fractures of long tubular bones (femur, tibia, humerus), in which bone fragments are fixed with a metal rod inserted into the bone marrow canal.

[0004] A rod (intramedullary rod, intraosseous pin or nail) is a metal implant inserted into the bone marrow canal to fix fragments of long tubular bones.

[0005] Duke's bend (Duke's angle) is an indicator in traumatology and orthopedics that determines the displacement of the proximal metaepiphysis of a long tubular bone in relation to its diaphysis.

[0006] Distal part of the rod - the lower end of the rod, which is inserted into the bone canal blocked in the area of ​​the lower metaphyseal part of the tubular bone.

[0007] Proximal part of the rod - the upper part of the rod, which is inserted into the bone canal blocked in the upper metaphyseal part of the tubular bone.

[0008] The diaphyseal part of the rod is the middle part of the rod, located in the medullary canal at the level of the diaphysis of the long tubular bone.

[0009] Isolated depression - a localized decrease in the thickness of the material on the surface of the product, not through, limited by the walls and bottom.

[0010] Medicinal composition - a mixture of a pharmacologically active substance (e.g. antibiotics, antitumor agents, anti-inflammatory agents, growth factors, anesthetics or antimicrobial agents) with a carrier (e.g. bone cement, hydrogel, polymer material, buffer solution, biodegradable polymer) intended for local delivery.

[0011] Various approaches to systemic and local therapy of purulent complications are known. One effective solution is the use of drug-loaded spacers placed directly at the site of the pathological lesion to specifically target the microflora. However, the clinical effectiveness of this method is largely determined by the kinetics of antibacterial agent release, which is not a stable value and depends on a complex set of interrelated technical, physicochemical, and other factors.

[0012] Thus, the kinetics of drug release depends on the manufacturer, viscosity [von Hertzberg-Boelch SP, Luedemann M, Rudert M, Steinert AF. PMMA Bone Cement: Antibiotic Elution and Mechanical Properties in the Context of Clinical Use. Biomedicines. 2022;10(8):1830. doi: 10.3390 / biomedicines10081830], polymerization duration, and mixing option [Meyer J., Spiegel CA, Hetzel S., Squire M. Vacuum-Mixing Significantly Changes Antibiotic Elution Characteristics of Commercially Available Antibiotic-Impregnated Bone Cements. J. Bone Jt. Surg. Am. Vol. 2011;93:2049-2056. doi: 10.2106 / JBJS.J.01777], the presence of additional inclusions and porosity of bone cement [Wu K., Chen YC, Hsu YM, Chang CH Enhancing Drug Release from Antibiotic-loaded Bone Cement Using Porogens. J. Am. Acad. Orthop. Surg. 2016;24:188-195. doi: 10.5435 / JAAOS-D-15-00469].Also, increased drug release from bone cement can be achieved by changing the geometric shape or architecture of the rod [Shafigulin RA, Galyautdinova AE, Kharin NV, Bespalov IA, Valeeva I.Kh., Boichuk SV, Akhtyamov IF, Sachenkov OA Effect of Lattice Structures on the Antibiotic Release from Bone Cement: In Vitro Study. Traumatology and Orthopedics of Russia. 2025;31(2):120-131. (In Russian). https: / / doi.org / 10.17816 / 2311-2905-17670.]. This approach allows for local delivery of the drug in the treatment of purulent complications. However, the architecture of such a rod is a lattice structure manufactured using additive technologies, specifically, either selective laser melting or selective laser sintering of titanium powder. This technology allows for the creation of complex periodic geometries with high precision.However, additive manufacturing produces a stepped surface with a roughness of Ra 5-25 μm for selective laser melting and Ra 5-18 μm for selective laser sintering [Paggetti, S.; Bedogni, E.; Veronesi, P. Factors Affecting the Surface Roughness of the As-Built Additively Manufactured Metal Parts: A Review. Metals 2025, 15, 1069. https: / / doi.org / 10.3390 / met15101069]. Post-processing of medical complex architectural products manufactured by additive manufacturing is a technological challenge. This is due to a combination of technological limitations, including geometric accessibility and initial surface quality [Fashanu FF et al. (2020). Review of Surface Finishing of Additively Manufactured Metal Implants. Proceedings of the ASME 2020 International Manufacturing Science and Engineering Conference, Wuersching, S.N., Westphal, D., Stawarczyk, B., Edelhoff, D., Kollmuss, M. (2023).Surface properties and initial bacterial biofilm growth on 3D-printed oral appliances: a comparative in vitro study. Clinical Oral Investigations 27:2667–2677].

[0013] For medical devices that come into contact with infected tissues, one of the important parameters is surface roughness, which promotes the adhesion of microorganisms and the formation of biofilms, which can neutralize the antibacterial effect of the rod (spacer) [Wuersching SN, Westphal D., Stawarczyk B., Edelhoff D., Kollmuss M. Surface properties and initial bacterial biofilm growth on 3D-printed oral appliances: a comparative in vitro study. Clinical Oral Investigations. 2023;27:2667-2677].

[0014] The surface quality requirements for osteosynthesis implants are regulated by the standard GOST ISO 14602-2012 "Non-active surgical implants. Osteosynthesis implants. Technical requirements." This standard establishes general requirements for biocompatibility, mechanical properties, and the absence of surface defects, but does not include specific numerical values ​​for roughness. Specific roughness values ​​are specified in the technical specifications for specific products. For example, in TU 32.50.22-005-05911137-2017 for the implant system for intramedullary osteosynthesis of the femur, a roughness of no more than Ra 0.8 μm is specified [https: / / zdr.plus / wp-content / uploads / 2025 / 04 / ip-300.00.00-sistema-implantatov-dlya-intramedullyarnogo-osteosinteza-bedrennoj-kosti.pdf].

[0015] Another approach to shaping the nail architecture is to create localized (isolated) cavities using subtractive methods, such as CNC milling, or combined technologies. The advantage of this approach is the ability to use nails with a surface roughness of no more than 0.8 μm after manufacturing. The roughness of the entire product after manufacturing depends on the type of post-processing. According to GOST R 70117-2022 "Surface Roughness. Selection Recommendations," the minimum roughness parameter Ra can reach 0.012 μm. In this case, the cavities are formed after nail manufacturing, before post-processing, which preserves the parameters of nail-bone interaction and avoids the negative impact of process roughness inherent in additive manufacturing.

[0016] The invention is known under the patent RU No. 2637292 “Device for intraosseous osteosynthesis”. The essence is a device for intraosseous osteosynthesis, containing a rod with drainage channels, a tip and a shank, a coupling with a central channel, connected at one end to the shank of the rod, and the other - to the drainage tube of the aspiration system, and fastening elements, characterized in that the device is equipped with an additional coupling, which has a central channel, drainage channels on the outer side surface, a hexagonal ledge for a key and radial recesses located on its proximal end, through oblique channels made at an angle of 45 ° relative to the vertical axis of the coupling and having an input and output through openings on the proximal end of the additional coupling and on its lateral surface, while the rod is made solid with curvilinear recesses consisting of a rectangular and a cylindrical part conjugated with it, which has an input and output through openings,located on the proximal end of the rod and on the lateral surface of its distal part, the fastening elements are made in the form of spokes, an additional coupling - with threads on the inner and outer lateral surfaces, the shank of the rod - with a thread on the outer lateral surface, and the coupling - with a thread on the inner lateral surface, the drainage channels of the rod and the curvilinear recesses are located on its outer lateral surface, alternating with each other, the spokes are located in the oblique channels of the additional coupling and in the cylindrical part of the curvilinear recess of the rod with the possibility of longitudinal movement along them, the additional coupling is mated with an internal thread with the external thread of the shank of the rod, which, in turn, is mated with an external thread with an internal thread of the coupling with a drainage tube, the drainage channels of the rod and the additional coupling are communicated with each other and with the central channel of the coupling, and the curvilinear recess is communicated with the central channel of the coupling,connected to the drainage tube of the aspiration system,

[0017] The disadvantage of the known technical solution compared to the declared technical solution is the impossibility of local delivery of the drug during the treatment of purulent complications.

[0018] Invention RU No. 2712803 “Intramedullary expanding rod for osteosynthesis of tubular bones” is known. The essence is an intramedullary expanding rod for osteosynthesis of tubular bones, consisting of a central axis, a clamping part, a sleeve, a handle, a tip, a clamping nut and two groups of peripheral spokes, the central axis is equipped with an external thread located in the head and tail parts, respectively, and has a thread at the beginning of the tail part for screwing into the clamping part and a thread in the tail part for tightening the clamping nut, in the head part there are three holes for fixing screws, of which two through holes are round in shape and a third hole made in the form of a straight through slot, while the head part is made with an expansion and has a transverse slot and a thread inside its cavity for installing and fixing the handle for rotating the axis, the clamping part is provided with teeth on the outside to prevent rotation in the bone,internal thread and "ears" for connection with spokes, the tip is made with one hole for the central axis and "ears" for connecting peripheral spokes, teeth on the outside to prevent rotation in the bone and is located in the tail part, in each group of peripheral spokes there are eight pieces, while the peripheral spokes are made with "ears" at the ends for connection with each other to ensure the mobility of the connection and two around the circumference, the sleeve is made with teeth on the outside to prevent rotation in the bone and connects two groups of spokes to each other, which, in turn, are movably connected to the clamping part and to the tip.

[0019] The disadvantage of the known technical solution compared to the declared technical solution is the impossibility of local delivery of the drug during the treatment of purulent complications.

[0020] Utility model RU No. 218468 "Lockable intramedullary nail for veterinary medicine" is known. The essence is a lockable intramedullary nail for veterinary medicine, made of titanium in the form of a rod with a rounded distal end and countersunk holes for locking screws, two holes at the proximal end and one at the distal end, a threaded hole and two diametrically located grooves for fastening the nail in a holder are made in the proximal end of the nail, characterized in that the surface of the nail has a protective diffusion layer of titanium oxide. The nail according to claim 1, characterized in that the protective diffusion layer is obtained by ion alloying in a low-pressure gas discharge in an argon-air mixture. The pin according to paragraph 2, characterized in that the air content in the argon-air mixture is 50 vol.%.

[0021] The disadvantage of the known technical solution compared to the declared technical solution is the absence of the Duke's bend in the rod, which does not correspond to the natural anterior bend of the diaphysis of the long tubular bone.

[0022] Invention RU No. 2498783 “Device for treating fractures of tubular bones of humans and animals with a short distal fragment with the possibility of lengthening, compression and shortening” is known.The essence is a device for treating fractures of tubular bones of humans and animals with a short and not only distal fragment with the possibility of compression, shortening and lengthening of the damaged segment is a Künscher pin with a thread in the channel of the proximal end, which also serves as a casing for the device, the other end is bored with a drill, characterized by the presence of 4 windows on the walls of the distal end for petals, and in the lumen of the casing - a rotating steel rod along the thread, pivotally connected to a cam, to which 2 pairs of petals are movably attached and placed in the channel of the distal end of the casing, and a sleeve with transverse notches on the outer surface for splines of the rod-shaft, introduced in the transverse direction through the trochanteric tubercles and "ears" previously put on the sleeve is screwed onto the threaded proximal end of the steel rod protruding from the lumen of the casing fixator, serves to compress and lengthen fragments.

[0023] The disadvantage of the known technical solution compared to the declared technical solution is the lack of holes for transosseous transverse blocking with screws, which reduces the stability of the structure to rotational and axial loads.

[0024] A utility model is known under RU Patent No. 233557 "Pin-cage for intramedullary osteosynthesis of the tibia with the ability to deliver active substances." The essence is a pin-cage for intramedullary osteosynthesis of the tibia with the ability to deliver active substances, consisting of an arcuately curved cannulated rod with proximal and distal holes for transosseous transverse locking with screws, an end threaded seating hole along the channel axis for an installation instrument, characterized in that it is made of titanium and the working part of the pin has a lattice three-dimensional structure for intraoperative filling it with a medicinal composition, wherein the length of the lattice section is at least one-third of the length of the pin, and the dimensions of the lattice holes are at least 3 mm in length and width.

[0025] The disadvantage of the known technical solution compared to the declared technical solution is the increased roughness of the pin cage R = 18 µm (see Example 21), which occurs during production using additive technologies.

[0026] The technical problem solved by this utility model and its technical result is the expansion of the arsenal of means for the specified purpose with an increase in the operational characteristics of the declared rod, which is due to:

[0027] - reducing roughness to Ra = 0.02-0.75 µm;

[0028] - the possibility of local delivery of a drug in the treatment of purulent complications;

[0029] - the possibility of performing osteosynthesis of long tubular bones due to the anatomical correspondence of the rod shape to the natural curvature of the diaphysis;

[0030] - increasing the reliability of fixation of the rod in the medullary canal due to the presence of holes for transosseous blocking with screws.

[0031] The essence of the claimed technical solution is a rod for intramedullary osteosynthesis of long tubular bones, made in the form of a curved rod with a roughness Ra in the range from 0.02 to 0.75 μm with holes for transosseous transverse blocking with screws, while isolated recesses with the possibility of placing a medicinal composition are made on the surface of the rod, and the shape of the rod is made anatomically corresponding to the curvature of the bone diaphysis. The rod according to claim 1, characterized in that the length of the curved rod is from 140 to 500 mm, the diameter of the proximal part is from 6 to 18 mm, the diameter of the diaphyseal part is from 6 to 14 mm, the diameter of the distal part is from 6 to 14 mm, the proximal Duke's bend is from 4 to 15 °. The rod according to any of claims 1 or 2, characterized in that the diaphyseal portion of the rod is made with a radius of curvature. The rod according to claim 3, characterized in that the radius of curvature is from 500 to 5000 mm. The rod according to any of claims1-4, characterized in that it is cannulated. The rod according to claim 5, characterized in that the diameter of the cannula is made in the range from 1 to 10 mm. The rod according to any of claims 1-6, characterized in that the diameter of either the proximal, or distal, or diaphyseal parts of the rod, or combinations thereof, is made variable. The rod according to claim 7, characterized in that the variable diameter is made in the range from 6 to 14 mm. The rod according to any of claims 1-8, characterized in that the length of the proximal part of the rod is from 30 to 160 mm. The rod according to any of claims 1-9, characterized in that the length of the distal part of the rod is from 30 to 110 mm. The rod according to any of claims 1-10, characterized in that the length of the diaphyseal portion of the rod is from 80 to 350 mm. The rod according to any of paragraphs. 1-11, characterized in that the proximal portion is made with an internal thread. The rod according to paragraph.12, characterized in that the diameter of the internal thread is made in the range from 2 to 14 mm, the length from 4 to 80 mm, the thread pitch from 0.25 to 2.5 mm. The rod according to any of paragraphs. 1-13, characterized in that the distal part is made with a chamfer. The rod according to paragraph 14, characterized in that the chamfer on the distal part is made with a bevel angle from 5 to 85° and a leg length from 0.5 to 7 mm. The rod according to any of paragraphs. 1-15, characterized in that it is made of stainless steel, or titanium, or tantalum, or their alloys. The rod according to any of paragraphs. 1-16, characterized in that the holes for transosseous transverse locking with screws are made on the proximal and / or distal part of the rod. The rod according to item 17, characterized in that the number of holes for transosseous transverse blocking with screws on the proximal part of the rod is from 1 to 8 pieces. The rod according to item18, characterized in that the axis of at least one hole for transosseous transverse blocking with screws of the proximal part is made at an angle to the longitudinal axis of the proximal part of the rod in the range from 10 to 170°. The rod according to claim 19, characterized in that at least one hole for transosseous transverse blocking with screws of the proximal part is made with an angle of inclination of the axis of the hole relative to the longitudinal axis of the proximal part of the rod in the range from 0 to 180° in the transverse plane. The rod according to claim 17, characterized in that the number of holes for transosseous transverse blocking with screws on the distal part of the rod is made from 1 to 8 pieces. The rod according to claim 21, characterized in that the axis of at least one hole for transosseous transverse blocking of the distal part with screws is made at an angle to the longitudinal axis of the distal part of the rod in the range from 10 to 170°. The rod according to claim22, characterized in that at least one hole for transosseous transverse locking with screws of the distal part is made with an angle of inclination of the axis of the hole relative to the longitudinal axis of the distal part of the rod in the range from 0 to 180° in the transverse plane. The rod according to claim 17, characterized in that the holes for transosseous transverse locking with screws of the distal and / or proximal part are made oval or round. The rod according to claim 24, characterized in that the holes for the transosseous hole for transosseous transverse locking with screws on the distal and / or proximal part are threaded. The rod according to claim 25, characterized in that the holes for transosseous transverse locking with screws on the distal and / or proximal part are made with a nominal thread diameter of 1 to 6 mm, a thread pitch of 0.5 mm to 2 mm. A rod according to any of claims1-26, characterized in that the isolated depressions are made in the form of: or truncated cones, or pyramids, or prisms, or cylinders, or spherical segments or combinations thereof, or with rounded edges, or a figured shape. The rod according to claim 27, characterized in that the isolated depressions are made with the overall dimensions: width from 0.25 to 6 mm, length from 0.25 to 350 mm, depth from 0.1 to 6 mm. The rod of claims 27 or 28, characterized in that the isolated depressions are located relative to the longitudinal axis of the rod sequentially, or spirally, or circumferentially, or combinations thereof. The rod according to any of claims 27-29, characterized in that the isolated depressions are located along the entire length of the rod. The rod according to any of claims 27-29, characterized in that the isolated recesses are located either in the distal, or in the proximal, or in the diaphyseal part of the rod, or in combinations thereof. The rod according to any one of paragraphs.27-31, characterized by the fact that the total number of isolated depressions in the distal, proximal and diaphyseal parts of the rod is not less than one.

[0032] The claimed technical solution is illustrated in Fig. 1-15.

[0033] Fig. 1 shows a schematic drawing of a rod for intramedullary osteosynthesis of long tubular bones with the ability to deliver active substances (hereinafter referred to as the claimed rod).

[0034] Fig. 2 shows a particular case of the implementation of the claimed rod, which has a radius of curvature.

[0035] Fig. 3 shows views of the non-cannulated claimed rod: 3a - view A, 3b - view B.

[0036] Fig. 4 shows views of the cannulated claimed rod: 4a - view A, 4b - view B.

[0037] Fig. 5 shows particular cases of the execution of isolated recesses.

[0038] Fig. 6 shows particular cases of the arrangement of isolated recesses.

[0039] Fig. 7 shows the claimed rod according to Example 1: 7a - in section, 7b - general view.

[0040] Fig. 8-15 show tables 1-8, respectively, which present the indicators of particular cases of execution of the declared rod.

[0041] The positions on the figures indicate:

[0042] 1 - distal part;

[0043] 2 - proximal part;

[0044] 3 - diaphyseal part;

[0045] 4 - isolated recesses;

[0046] 5 - oval holes of the proximal part;

[0047] 6 - round holes of the proximal part;

[0048] 7 - oval holes of the distal part;

[0049] 8 - round holes of the distal part;

[0050] 9 - internal thread on the proximal part;

[0051] 10 - chamfer on the distal part;

[0052] 11 - cannula;

[0053] 5.1 - non-threaded oval-shaped hole (Fig. 7), located at an angle β2=90° (Fig. 1) and an angle γ2=0° (Fig. 4);

[0054] 6.1 - two threaded holes (Fig. 7), located at an angle β2=90° (Fig. 1) and an angle γ2=0° (Fig. 4);

[0055] 6.2 - a non-threaded hole of a round shape (Fig. 7), located at an angle β2=15° (Fig. 1) and an angle γ2=95° (Fig. 4);

[0056] 6.3 - non-threaded hole of circular shape (Fig. 7), located at an angle β2=90° (Fig. 1) and an angle γ2=45° (Fig. 4);

[0057] 6.4 - a non-threaded hole of a round shape (Fig. 7), located at an angle β2=90° (Fig. 1) and an angle γ2=135° (Fig. 4);

[0058] 7.1 - a non-threaded oval-shaped hole (Fig. 7), located at an angle β1=90° (Fig. 1) and an angle γ1=0° (Fig. 4);

[0059] 8.1 - threaded hole (Fig. 7), located at an angle β1=90° (Fig. 1) and an angle γ1=0° (Fig. 4);

[0060] 8.2 - a non-threaded hole of a round shape (Fig. 7), located at an angle β1=90° (Fig. 1) and an angle γ1=135° (Fig. 4);

[0061] 8.3 - a non-threaded hole of a round shape (Fig. 7), located at an angle β1=90° (Fig. 1) and an angle γ1=45° (Fig. 4);

[0062] 8.4 - non-threaded hole of circular shape (Fig. 7), located at an angle β1=90° (Fig. 1) and an angle γ1=90° (Fig. 4).

[0063] L - the length of the declared rod;

[0064] L1 - length of distal part;

[0065] L2 - length of proximal part;

[0066] L3 - length of the diaphyseal part;

[0067] Lp - length of internal thread on the proximal part;

[0068] Lc - length of the chamfer leg on the distal part;

[0069] D1 - diameter of the distal part;

[0070] D2 - diameter of the proximal part;

[0071] D3 - diameter of the diaphyseal part;

[0072] Dp - diameter of the internal thread of the proximal part;

[0073] Dk - cannula diameter;

[0074] α - proximal Duke's curve;

[0075] β1 - angle of the hole axis to the longitudinal axis of the distal part;

[0076] β2 - angle of the axis of the opening to the longitudinal axis of the proximal part;

[0077] γ1 - the angle of inclination of the hole axis relative to the longitudinal axis of the distal part of the rod in the transverse plane;

[0078] γ2 - the angle of inclination of the hole axis relative to the longitudinal axis of the proximal part of the rod in the transverse plane;

[0079] θ - chamfer angle;

[0080] R - radius of curvature.

[0081] The following is a description of the claimed technical solution.

[0082] The claimed technical result is achieved by developing a rod for intramedullary osteosynthesis of long tubular bones with the ability to deliver active substances (the claimed rod) (Fig. 1).

[0083] The claimed rod consists of a curved rod made with a roughness in the range from 0.02 to 0.75 µm, with holes 5-9 (Fig. 1) for transosseous transverse blocking with screws, while isolated recesses 4 (Fig. 1) are made on the surface of the rod with the possibility of placing active substances.

[0084] In special cases of execution, the declared rod is made in the following size:

[0085] length (L in Fig. 1) from 140 to 500 mm,

[0086] proximal diameter (D2 in Fig. 1) from 6 to 18 mm,

[0087] diameter of the diaphyseal part (D3 in Fig. 1) from 6 to 14 mm,

[0088] the diameter of the distal part (D1 in Fig. 1) is from 6 to 14 mm,

[0089] proximal Duke's curve (α in Fig. 1) from 4 to 15°.

[0090] In a particular case of execution, the diaphyseal part is made without a radius of curvature.

[0091] In a particular case of execution, the diaphyseal part is made with a radius of curvature (R in Fig. 2).

[0092] In special cases, the radius of curvature R is made from 500 to 5000 mm.

[0093] In a particular case of implementation, the claimed rod is made non-cannulated (Fig. 3).

[0094] In a particular case of implementation, the claimed rod is made cannulated (12 in Fig. 4).

[0095] In particular cases of implementation, the diameter of the cannula (Dk in Fig. 4) of the declared rod is made from 1 to 10 mm.

[0096] In particular cases of execution, the diameter of either the proximal (D2 in Fig. 1), or distal (D1 in Fig. 1), or diaphyseal (D3 in Fig. 1) parts of the claimed rod, or their combinations, is made variable.

[0097] In special cases, the variable diameter is made from 6 to 14 mm.

[0098] In particular cases of execution, the length of the proximal part (L2 in Fig. 1) of the claimed rod is made from 30 to 160 mm.

[0099] In particular cases of execution, the length of the distal part (L1 in Fig. 1) of the claimed rod is made from 30 to 110 mm.

[0100] In particular cases of execution, the length of the diaphyseal part (L3 in Fig. 1) of the declared rod is made from 80 to 350 mm.

[0101] In special cases of execution, the proximal part of the claimed rod is made with an internal thread (10 in Fig. 1).

[0102] In particular cases of execution, the internal thread on the proximal part of the declared rod is made with the following dimensions: internal thread diameter (Dp in Fig. 1) from 2 to 14 mm, length (Lp in Fig. 1) from 4 to 80 mm, thread pitch from 0.25 to 2.5 mm.

[0103] In a particular case of execution, the distal part of the declared rod is made without a chamfer.

[0104] In a particular case of execution, the distal part of the claimed rod is made with a chamfer (11 in Fig. 1).

[0105] In special cases of execution, the chamfer on the distal part of the declared rod is made with the following dimensions: bevel angle (θ in Fig. 1) from 5 to 85°, leg length (Lc in Fig. 1) from 0.5 to 7 mm.

[0106] In specific cases, the stated rod is made of either stainless steel, or titanium, or tantalum, or their alloys.

[0107] In special cases, holes for transosseous transverse blocking with screws are made on the proximal (5-7 in Fig. 1) and / or distal (8, 9 in Fig. 1) part of the claimed rod.

[0108] In special cases of execution, the number of holes for transosseous transverse blocking with screws on the proximal part of the declared rod is made from 1 to 8 pieces.

[0109] In particular cases of execution, at least the axis of one hole (7 in Fig. 1) for transosseous transverse blocking with screws of the proximal part of the claimed rod is made at an angle to the longitudinal axis of the proximal part of the rod (β2 in Fig. 1) in the range from 10° to 170°.

[0110] In particular cases of making at least one hole (7 in Fig. 1) for transosseous transverse blocking with screws of the proximal part of the claimed rod, it is made with an angle of inclination of the axis of the hole relative to the longitudinal axis of the proximal part (γ2 in Fig. 1) of the rod in the range from 0 to 180° in the transverse plane.

[0111] In special cases of execution, the number of holes for transosseous transverse blocking with screws on the distal part of the declared rod is made from 1 to 8 pieces.

[0112] In particular cases of execution, the axis of at least one hole (8 in Fig. 1) for transosseous transverse blocking with screws of the distal part of the claimed rod is made at an angle to the longitudinal axis of the distal part (β1 in Fig. 1) of the rod in the range from 10 to 170°.

[0113] In particular cases of execution, at least one hole (8 in Fig. 1) for transosseous transverse blocking with screws of the distal part of the claimed rod is made with an angle of inclination of the axis of the hole relative to the longitudinal axis of the distal part (γ1 in Fig. 1) of the rod in the range from 0 to 180° in the transverse plane.

[0114] In special cases of making holes for transosseous transverse blocking with screws of the distal and / or proximal part of the claimed rod, they are made oval (5, 9 in Fig. 1) or round (6-8 in Fig. 1) in shape.

[0115] In special cases of making holes for transosseous transverse blocking with screws on the distal and / or proximal part of the claimed rod, they are made either threaded or non-threaded (5-9 in Fig. 1).

[0116] In special cases of making holes for transosseous transverse blocking with screws on the distal and / or proximal part of the declared rod, the following dimensions are made: nominal thread diameter from 1 to 6 mm, thread pitch from 0.5 to 2 mm.

[0117] In particular cases of execution, isolated depressions are made in the form of: or truncated cones (Fig. 5a, Fig. 5b), or prisms (Fig. 5c), or cylinders (Fig. 5g, Fig. 5d), or spherical segments (Fig. 5e, Fig. 5k), or pyramids (Fig. 5g), or their combinations (Fig. 5z) with rounded (Fig. 5i, Fig. 5l) or not rounded (Fig. 5a, Fig. 5b, Fig. 5c, Fig. 5g, Fig. 5d, Fig. 5e, Fig. 5g, Fig. 5z, Fig. 5k) edges, or figured shape (Fig. 5m, Fig. 5n, Fig. 5o, Fig. 5p, Fig. 5r).

[0118] In special cases, isolated recesses are made with the following overall dimensions: width from 0.25 to 6 mm, length from 0.25 to 350 mm, depth from 0.1 to 6 mm.

[0119] In particular cases of execution, isolated recesses are located relative to the longitudinal axis of the claimed rod sequentially (Fig. 6a), or spirally (Fig. 6b), or circumferentially (Fig. 6c), or combinations thereof (Fig. 6d).

[0120] In special cases of execution, isolated recesses are located along the entire length of the declared rod (Fig. 6d).

[0121] In special cases of execution, isolated recesses are located either in the distal, or in the proximal, or in the diaphyseal (Fig. 6e) part of the rod, or in their combinations (Fig. 6g).

[0122] In specific embodiments, the total number of isolated recesses in the distal, proximal, and diaphyseal portions of the claimed rod is not less than one. One recess on the proximal portion of the claimed rod is shown in Fig. 6z.

[0123] The claimed rod is manufactured, for example, using a combination of traditional subtractive and combined metal processing technologies, ensuring the achievement of the required performance characteristics, including surface roughness Ra = 0.02-0.75 μm and the formation of isolated recesses for placing the medicinal composition. Biocompatible metals and alloys are used as the source material, selected depending on the required mechanical characteristics, corrosion resistance and operating conditions of the implant, for example, stainless steel grades 12X18H10T, 08X18H10T, 03X17H14M3, 316LVM, 304LVM; Titanium and its alloys - VT1-0 (pure titanium, CP-Ti, Grade 4), VT5, VT6 (Ti-6Al-4V), VT6s, VT-16, VT14, OT-4, Ti-6Al-7Nb, Ti-15Zr, Ti-Nb-Ta-Zr; as well as tantalum in pure or porous form. A round rod, for example, is used as a blank.When fabricating a cannulated rod, the central hole is formed, for example, by drilling on a CNC machine. The proximal Herzog bend and the radius of curvature of the rod are formed, for example, by cold or hot bending on a mandrel followed by thermal stress relief. Holes for transosseous transverse locking with screws, including oval and round, threaded and non-threaded ones, are made, for example, on CNC machines. Isolated recesses for placing the drug composition are formed after the basic geometry of the rod is achieved, but before final surface finishing, for example, by CNC milling, electrical discharge machining, or laser ablation. Surface finishing post-processing includes, for example, mechanical grinding and polishing, electrochemical polishing, chemical etching, and passivation.

[0124] The following are examples of the implementation of the claimed technical solution.

[0125] Example 1. Manufacturing of an intramedullary cannulated nail for osteosynthesis, 235 mm long, made of BT6 (Ti-6Al-4V), with sequential, spiral and circumferential distribution of isolated, figured-shaped depressions for local delivery of the active substance.

[0126] The stated rod (Fig. 7) was manufactured from a calibrated round bar using sequential machining. The basic geometry was formed by numerically controlled turning, and the cannula was produced by deep drilling. The proximal bend was achieved by bending and heat treatment. Holes for transosseous transverse locking screws and isolated recesses were milled on a numerically controlled machine. The final surface roughness was achieved by post-processing, including mechanical, electrochemical, and chemical polishing.

[0127] The stated rod was manufactured with the following parameters:

[0128] roughness 0.6 μm;

[0129] length (L in Fig. 1) 235 mm;

[0130] proximal diameter (D2 in Fig. 1) 12 mm;

[0131] diameter of the diaphyseal part (D3 in Fig. 1) 12 mm;

[0132] the diameter of the distal part (D1 in Fig. 1) is 12 mm;

[0133] proximal Duke's curve (α in Fig. 1) 13°;

[0134] the diaphyseal part is made without a radius of curvature (R in Fig. 2);

[0135] is cannulated (12 in Fig. 4);

[0136] cannula diameter (Dk in Fig. 4) 4 mm;

[0137] the diameter of both the proximal (D2 in Fig. 1) and distal (D3 in Fig. 1) parts is made constant, the diameter of the diaphyseal (D1 in Fig. 1) is made variable;

[0138] Variable diameter range from 8mm to 12mm;

[0139] length of proximal part (L2 in Fig. 1) 94 mm;

[0140] length of distal part (L1 in Fig. 1) 56 mm;

[0141] length of diaphyseal part (L3 in Fig. 1) 87 mm;

[0142] The proximal part is made with an internal thread (10 in Fig. 1).

[0143] The diameter of the internal thread on the proximal part (Dp in Fig. 1) is 8 mm;

[0144] length of internal thread on the proximal part (Lp in Fig. 1) 20 mm;

[0145] The pitch of the internal thread on the proximal part is 1.25 mm;

[0146] The distal part is chamfered;

[0147] bevel angle (θ in Fig. 1) of the chamfer on the distal part is 74°;

[0148] The length of the leg (Lc in Fig. 1) of the chamfer on the distal part is 2.7 mm.

[0149] The rod is made of titanium alloy VT6 (Ti-6Al-4V);

[0150] holes for transosseous transverse blocking with screws are made on the proximal and distal (1-5 in Fig. 7a) parts;

[0151] holes 6-11 (Fig. 7a) for transosseous transverse blocking with screws on the proximal part are made in the amount of 6 pcs.;

[0152] the axes of the holes 6-11 (Fig. 7a) for transosseous transverse blocking with screws of the proximal part are made at angles of 90°, 90°, 15°, 90°, 90°, 90°, respectively to the longitudinal axis of the proximal part of the rod (β2 in Fig. 1);

[0153] the axes of the holes 6-11 (Fig. 7a) for transosseous transverse blocking with screws of the proximal part are made with an angle of inclination of the axis of the hole of 0°, 0°, 95°, 0°, 45°, 135°, respectively, relative to the longitudinal axis of the proximal part (γ2 in Fig. 1) of the rod in the transverse plane;

[0154] holes 1-5 (Fig. 7a) for transosseous transverse blocking with screws on the distal part are made in the amount of 5 pieces;

[0155] the axes of the holes 1-5 (Fig. 7a) for transosseous transverse blocking with screws of the distal part are made at angles of 90°, 90°, 90°, 90°, 90°, respectively to the longitudinal axis of the distal part (β1 in Fig. 1) of the rod;

[0156] the axes of the holes 1-5 (Fig. 7a) for transosseous transverse blocking with screws of the distal part are made with an angle of inclination of the axis of the hole of 0°, 135°, 45°, 0°, 0°, respectively, relative to the longitudinal axis of the distal part (γ1 in Fig. 1) of the rod in the transverse plane;

[0157] holes 5, 7 (Fig. 7a) for transosseous transverse blocking with screws of the distal and proximal parts are made in an oval shape;

[0158] holes 1-4, 6, 8-9 (Fig. 7a) for transosseous transverse blocking with screws of the distal and proximal parts are made in a round shape;

[0159] Holes 2-5, 7-8, 10-11 for transosseous transverse locking with screws on the distal and proximal parts are not threaded. Holes 1, 6, 9 for transosseous transverse locking with screws on the distal and proximal parts are threaded;

[0160] The threaded holes (1, 6, 9 in Fig. 7a) for transosseous transverse blocking with screws on the distal and proximal parts are made with the following dimensions: nominal thread diameter 4 mm, thread pitch 0.5 mm.

[0161] isolated recesses are made in a figured shape, the edges are rounded (Fig. 5p);

[0162] insulated recess width 4mm;

[0163] length of isolated recesses 5mm;

[0164] insulated recess depth 2mm;

[0165] isolated recesses are located relative to the longitudinal axis of the rod both sequentially, and spirally, and circumferentially;

[0166] isolated recesses are not located along the entire length of the rod - there are no isolated recesses near the holes for transosseous transverse blocking with screws on the distal and proximal part;

[0167] isolated recesses are located in the distal, proximal and diaphyseal parts of the rod;

[0168] total number of isolated depressions on the distal, proximal and diaphyseal parts 261 pcs.

[0169] The roughness of the rod is 0.6 μm, which meets the requirements of technical specifications, for example, in TU 32.50.22-005-05911137-2017 for the implant system for intramedullary osteosynthesis of the femur, the roughness is specified to be no more than Ra 0.8 μm [https: / / zdr.plus / wp-content / uploads / 2025 / 04 / ip-300.00.00-sistema-implantatov-dlya-intramedullyarnogo-osteosinteza-bedrennoj-kosti.pdf]. Compared to the analogue according to patent RU No. 233557, manufactured using additive technologies, the roughness Ra is reduced from 18 μm to 0.6 μm, which proves the achievement of the declared technical result.

[0170] The nail according to Example 1 can be used with selected parameters, for example, for intramedullary osteosynthesis of the tibia. Compared to similar nails RU No. 2637292 and RU No. 2712803, the claimed nail according to Example 1 (Fig. 7b) has the ability to locally deliver a drug during the treatment of purulent complications: isolated recesses serve for local delivery of the active substance by placing, for example, bone cement impregnated with an antibiotic, which demonstrates the achievement of the stated technical result.

[0171] Compared with the analogue RU No. 218468, the rod according to Example 1 (Fig. 7b) provides the possibility of performing osteosynthesis of long tubular bones due to the presence of the proximal Duke's bend, which proves the achievement of the stated technical result.

[0172] Compared with the analogue RU No. 2498783, the rod according to Example 1 (Fig. 7b) ensures the stability of the structure to rotational and axial loads due to the presence of holes for transosseous transverse blocking with screws, which proves the achievement of the declared technical result.

[0173] Examples 2-20. Specific cases of intramedullary nail design for osteosynthesis with isolated recesses for local delivery of the active substance, differing in the material of manufacture, geometric parameters, shape, size and distribution of the recesses, as well as the configuration of the holes for transosseous blocking.

[0174] The sequence of actions according to Example 1 is carried out, characterized in that different materials of manufacture, geometric parameters, shape, dimensions and nature of distribution of recesses, as well as the configuration of holes for transosseous blocking are selected.

[0175] The results are shown in Tables 1-8 in Fig. 8-15, respectively.

[0176] The stated technical result was achieved:

[0177] - roughness reduced to Ra=0.02-0.75 µm;

[0178] - the possibility of local delivery of the drug during the treatment of purulent complications is ensured due to the presence of isolated depressions;

[0179] - the possibility of performing osteosynthesis of long tubular bones is ensured due to the anatomical correspondence of the rod shape to the natural curvature of the diaphysis;

[0180] - the reliability of fixation of the rod in the medullary canal is increased due to the presence of holes for transosseous blocking with screws.

[0181] Example 21. Determination of the roughness of a pin cage based on an analog - RU patent No. 233557.

[0182] The intramedullary tibial osteosynthesis nail cage with the ability to deliver active substances under RU patent #233557 was manufactured using additive technologies, namely selective laser melting, on a RussianSLM FACTORY 3D printer from Ti6Al4V. The Ti6Al4V powder fraction was 15-50 μm, the layer thickness was 30 μm, and the laser power was 210 W. The surface roughness of the product was determined by contact profilometry in accordance with the requirements of GOST ISO 4287-2014. Measurements were performed on a Bruker DektakXT profilometer using a diamond tip with a curvature radius of 2 μm and a clamping force of 3 mg. The discretization step was 0.25 mm, and the baseline length was 4.8 mm.

[0183] The arithmetic mean value of the roughness parameter Ra, calculated based on the results of fivefold measurements on the surface areas of the pin cage, was 18 μm.

[0184] Compared to the analogue according to RU patent No. 233557, manufactured using additive technologies, the roughness of the declared rod Ra is reduced from 18 µm to 0.02-0.75 µm, which proves the achievement of the declared technical result.

[0185] The rods according to Examples 2-20 can be used with the selected parameters, for example, for intramedullary osteosynthesis of the tibia (Examples 9-15), humerus (Examples 2-8), femur (Examples 16-20). In comparison with analogs RU No. 2637292, RU No. 2712803, the claimed rod according to Examples 2-20 (Fig. 7b) has the ability to locally deliver a drug in the treatment of purulent complications: isolated depressions serve for local delivery of the active substance, by placing in them, for example, bone cement impregnated with an antibiotic, which proves the achievement of the declared technical result.

[0186] From the above, it can be concluded that the applicant has solved the identified technical problem and achieved the stated technical result: the arsenal of means for the specified purpose has been expanded with an increase in the performance characteristics of the declared rod, namely:

[0187] - the roughness Ra has been reduced from 18 µm to 0.02-0.75 µm compared to the analogue RU No. 233557, manufactured using additive technologies (see Examples 1-20, Fig. 8);

[0188] - compared to analogues RU No. 2637292, RU No. 2712803, the claimed rod has the ability to locally deliver a drug in the treatment of purulent complications. This logically follows from the information known from the prior art: according to [Ständert, V., K. Borcherding, N. Bormann, G. Schmidmaier, I. Grunwald, and B. Wildemann. 2021. Antibiotic-loaded amphora-shaped pores on a titanium implant surface enhance osteointegration and prevent infections. Bioactive Materials, 6(8):2331-2345], the presence of surface recesses in the rod design ensures the formation of local reservoirs of the drug with subsequent prolonged release to the site of infection. Thus, the claimed technical solution allows for achieving a high local concentration of the antibacterial agent, which increases the effectiveness of the treatment of purulent complications compared to analogues that do not provide the possibility of targeted drug delivery.

[0189] - compared to the analogue RU No. 218468, the declared rod has the ability to perform osteosynthesis of long tubular bones due to the anatomical correspondence of the rod shape to the natural curvature of the diaphysis;

[0190] - compared to the analogue RU No. 2498783, the declared rod has increased reliability of fixation in the medullary canal due to the presence of holes for transosseous blocking with screws.

Claims

1. A rod for intramedullary osteosynthesis of long tubular bones, made in the form of a curved rod with a roughness Ra in the range from 0.02 to 0.75 μm with holes for transosseous transverse blocking with screws, while isolated recesses are made on the surface of the rod with the possibility of placing a medicinal composition, and the shape of the rod is made anatomically corresponding to the curvature of the bone diaphysis.

2. The rod according to claim 1, characterized in that the length of the curved rod is from 140 to 500 mm, the diameter of the proximal part is from 6 to 18 mm, the diameter of the diaphyseal part is from 6 to 14 mm, the diameter of the distal part is from 6 to 14 mm, the proximal Duke's bend is from 4 to 15°.

3. A rod according to any one of paragraphs 1 or 2, characterized in that the diaphyseal part of the rod is made with a radius of curvature.

4. The rod according to paragraph 3, characterized in that the radius of curvature is from 500 to 5000 mm.

5. A rod according to any of paragraphs 1-4, characterized in that it is cannulated.

6. The rod according to item 5, characterized in that the diameter of the cannula is in the range from 1 to 10 mm.

7. A rod according to any one of paragraphs 1-6, characterized in that the diameter of either the proximal, or distal, or diaphyseal parts of the rod, or combinations thereof, is made variable.

8. The rod according to item 7, characterized in that the variable diameter is made in the range from 6 to 14 mm.

9. A rod according to any one of paragraphs 1-8, characterized in that the length of the proximal part of the rod is from 30 to 160 mm.

10. A rod according to any one of paragraphs 1-9, characterized in that the length of the distal part of the rod is from 30 to 110 mm.

11. A rod according to any one of paragraphs 1-10, characterized in that the length of the diaphyseal part of the rod is from 80 to 350 mm.

12. A rod according to any one of paragraphs 1-11, characterized in that the proximal part is made with an internal thread.

13. The rod according to item 12, characterized in that the diameter of the internal thread is in the range from 2 to 14 mm, the length from 4 to 80 mm, the thread pitch from 0.25 to 2.5 mm.

14. A rod according to any one of paragraphs 1-13, characterized in that the distal part is made with a chamfer.

15. The rod according to item 14, characterized in that the chamfer on the distal part is made with a bevel angle of 5 to 85° and a leg length of 0.5 to 7 mm.

16. A rod according to any of paragraphs 1-15, characterized in that it is made of stainless steel, titanium, tantalum, or their alloys.

17. A rod according to any one of paragraphs 1-16, characterized in that the holes for transosseous transverse blocking with screws are made on the proximal and / or distal part of the rod.

18. The rod according to item 17, characterized in that the number of holes for transosseous transverse blocking with screws on the proximal part of the rod is from 1 to 8 pieces.

19. The rod according to claim 18, characterized in that the axis of at least one hole for transosseous transverse blocking with screws of the proximal part is made at an angle to the longitudinal axis of the proximal part of the rod in the range from 10 to 170°.

20. The rod according to claim 19, characterized in that at least one hole for transosseous transverse blocking with screws of the proximal part is made with an angle of inclination of the axis of the hole relative to the longitudinal axis of the proximal part of the rod in the range from 0 to 180° in the transverse plane.

21. The rod according to item 17, characterized in that the number of holes for transosseous transverse blocking with screws on the distal part of the rod is from 1 to 8 pieces.

22. The rod according to claim 21, characterized in that the axis of at least one hole for transosseous transverse blocking with screws of the distal part is made at an angle to the longitudinal axis of the distal part of the rod in the range from 10 to 170°.

23. The rod according to claim 22, characterized in that at least one hole for transosseous transverse blocking with screws of the distal part is made with an angle of inclination of the axis of the hole relative to the longitudinal axis of the distal part of the rod in the range from 0 to 180° in the transverse plane.

24. The rod according to claim 17, characterized in that the holes for transosseous transverse blocking with screws of the distal and / or proximal part are made oval or round in shape.

25. The rod according to item 24, characterized in that the holes for transosseous transverse blocking with screws on the distal and / or proximal part are threaded.

26. The rod according to item 25, characterized in that the holes for transosseous transverse blocking with screws on the distal and / or proximal part are made with a nominal thread diameter from 1 to 6 mm, a thread pitch from 0.5 mm to 2 mm.

27. A rod according to any one of paragraphs 1-26, characterized in that the isolated recesses are made in the form of: either truncated cones, or pyramids, or prisms, or cylinders, or spherical segments or combinations thereof, or with rounded edges, or of a figured shape.

28. The rod according to item 27, characterized in that the isolated recesses are made with the following overall dimensions: width from 0.25 to 6 mm, length from 0.25 to 350 mm, depth from 0.1 to 6 mm.

29. The rod according to paragraphs 27 or 28, characterized in that the isolated recesses are located relative to the longitudinal axis of the rod sequentially, or spirally, or circumferentially, or combinations thereof.

30. A rod according to any one of paragraphs 27-29, characterized in that the isolated recesses are located along the entire length of the rod.

31. A rod according to any one of paragraphs 27-29, characterized in that the isolated recesses are located either in the distal, or in the proximal, or in the diaphyseal part of the rod, or in combinations thereof.

32. A rod according to any one of paragraphs 27-31, characterized in that the total number of isolated depressions in the distal, proximal and diaphyseal parts of the rod is not less than one.

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