CN219306892U

CN219306892U - Single-rod primary-secondary nail external fixing frame and primary-secondary nail thereof

Info

Publication number: CN219306892U
Application number: CN202222956825.3U
Authority: CN
Inventors: 陈聚伍
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-11-07
Filing date: 2022-11-07
Publication date: 2023-07-07
Anticipated expiration: 2032-11-07

Abstract

The utility model discloses a single-rod primary-secondary nail external fixation frame and a primary-secondary nail thereof, wherein the external fixation frame comprises a clamping plate, a connecting rod and a primary-secondary nail, the primary-secondary nail comprises a nail body, a self-tapping section and a primary-secondary nail cap part, a notch is arranged at the eccentric position of the primary-secondary nail cap part and is used for sleeving the primary-secondary nail, the clamping plate is U-shaped, a through-nail round hole is arranged at the bottom of the clamping plate, two side walls of the clamping plate penetrate through and are provided with nail rod perforations, a matching gap between the two side walls of the clamping plate is a locking seam, the head end of a rod body of the connecting rod is provided with a shaft seat, the center of the shaft seat is provided with a shaft hole, and the tail end of the rod body is provided with a screw rod section. The external fixing frame disclosed by the utility model has a simple structure, the trauma to a patient caused by an operation can be reduced as much as possible, the volume and the weight of the external support are reduced, the mobility of a rehabilitation period is improved, the compression of the external support to a fracture part is reduced, the primary and secondary nails have high structural strength and small processing difficulty, the self-tapping sections of the primary and secondary nails are respectively screwed into bones, and the connection strength and the anti-rotation strength between the nails and the bones are improved.

Description

Single-rod primary-secondary nail external fixing frame and primary-secondary nail thereof

Technical Field

The utility model belongs to the technical field of fracture positioning frames, and particularly relates to an external fixing frame and a primary and secondary nail assembly for positioning and fixing fracture only through a single connecting rod and four nails.

Background

The fixing mode for fracture comprises steel plate fixing, external frame fixing and intramedullary nail fixing, wherein the steel plate internal fixing has the advantages of simple operation and short learning period, but the prior nail-plate combined structure has the following problems: the wound is large, the probability of accidental injury is high, infection and disunion are caused, healing is delayed, broken nails and broken plates occur, postoperative scars are large, the appearance is influenced, and the principle of minimally invasive is not met. The fixing frame for treating fracture has various defects, but has complex structure and a plurality of components, the existing external frame is fixed by driving female nails vertically towards two sides of the fracture, and then the fixing frame is formed by mutually connecting a plurality of universal joints and connecting rods. The external frame is fixed to be the fracture fixed mode that is commonly used, and current external frame is fixed adopts to drive into female nail to fracture both sides vertically more, then constitutes the mount through a plurality of universal joints and connecting rod interconnect, because the universal joint needs to have the transverse rotation and lock and the vertical rotation and lock dead regulation relation, universal wheel volume is great, and whole outer frame volume is great, and fracture patient carries inconveniently after the installation is used, and fracture position can't wear to change clothes, influences the activity of involving in, and it is easy and simple to handle to wait to develop a fracture fixed external frame that convenient to carry and easy be accepted by the patient.

Femoral shaft fractures and distal femur fractures are clinically common fractures. Surgical treatment is the first treatment method, and before intramedullary nail fixation and bone plate fixation are carried out, the two ends of the fracture part are needed to be in reset butt joint and fixation. Traction is an important means of reducing femoral fractures and restoring lower limb length. At present, the tractor for resetting patients with lower limb fracture in various hospitals mainly comprises a traction rope and pulleys, one end of the traction rope is connected with a bracket at the fracture, the other end of the traction rope bypasses the pulleys and hangs weights, and traction force is controlled by manually increasing the number of the weights or changing the weight of the weights. Because the patient can move when lying on the sickbed, the traction force changes, and once the traction force changes, the weight is adjusted. For the existing manual control method, the frequent replacement of weights is very inconvenient, so that not only is the burden on the work of hospital nurses increased, but also the trouble is brought to the reduction of fracture patients. On the other hand, because the one end of haulage rope is connected fracture position distal end, and needs the dynamics of pulling great, leads to fracture distal end to be pulled the direction only can follow the haulage rope direction, and fracture distal end and near-end often have crisscross and torsion condition after the fracture, belong to the rigidity through the mode of pulling fracture distal end in prior art and pull, be difficult for carrying out rotation and swing to the fracture to can't reach best reset effect.

The external frame is fixed to be the fracture fixed mode that is commonly used, and current external frame is fixed adopts to drive into female nail to fracture both sides vertically more, then constitutes the mount through a plurality of universal joints and connecting rod interconnect, because the universal joint needs to have the transverse rotation and lock and the vertical rotation and lock dead regulation relation, universal wheel volume is great, and whole outer frame volume is great, and fracture patient carries inconveniently after the installation is used, and fracture position can't wear to change clothes, influences the activity of involving in, and it is easy and simple to handle to wait to develop a fracture fixed external frame that convenient to carry and easy be accepted by the patient.

The external fracture fixing frame installation component with the publication number of CN 109009372A has the advantages that the external fracture fixing frame installation component is simple in structure, a patient can carry fewer external fixing frames, but the operation process is complex, the number of structural components required to be matched is large, and the implementation difficulty is high. The fixing frame of CN212307999U is provided with a self-locking structure, but the combination of the fixing frame and the main nail is of a cylindrical structure, the connection degree of the main nail and the bone is weak, the main nail is difficult to resist the problem that the main nail rotates due to the possibly large-amplitude movement, and the main nail structure of the scheme has the advantages of high processing difficulty, high cost and poor strength.

Disclosure of Invention

Aiming at the problems of various defects existing in the prior fracture fixation mode, the utility model provides the single-rod primary-secondary nail external fixation frame and the primary-secondary nail which have the advantages of simplified structure and better practicability, are suitable for the condition that the span of a fracture area is small and multi-nail fixation cannot be realized, so as to achieve the purposes of minimally invasive and greatly simplifying the structure, facilitate flexible actions of a patient in the convalescence period and reduce the medical cost.

The technical scheme for solving the technical problems is that the single-rod primary-secondary-nail external fixing frame mainly comprises a head end clamping plate, a tail end clamping plate, a connecting rod, primary-secondary-terminal primary nails and the like, wherein the primary-secondary nails comprise primary nails and secondary nails, each primary nail comprises a nail body, a lower-section primary-nail self-tapping section and a middle primary nail cap part, each secondary nail comprises a nail body, a lower-section secondary-nail self-tapping section and a secondary nail cap part, a notch is formed in the eccentric position of each primary nail cap part and is matched with the nail body or the secondary nail cap part of each secondary nail together, the clamping plate is U-shaped, through nail round holes are formed in the bottom of the clamping plate, nail rod perforations are formed in the two side walls of the clamping plate in a penetrating mode, matching gaps between the two side walls of the clamping plate are locking joints, and the diameter of each through nail round hole is larger than the width of each locking joint; the head end of the rod body of the connecting rod is provided with a shaft seat, the center of the shaft seat is provided with a shaft hole, and the tail end of the rod body is provided with a screw rod section.

In the external fixing frame, convex and concave patterns along the axial direction are arranged in the nail penetrating holes of each clamping plate, or convex and concave patterns are arranged on the outer sides of the primary and secondary nails, so that the locking degree between the clamping plates and the primary and secondary nails is improved.

In the external fixing frame, convex-concave anti-skid patterns are arranged around the nail rod perforations on the two outer side walls of each clamping plate.

In the external fixing frame, a composite rivet penetrating hole is further formed in the clamping plate and used for sleeving and pressing a rivet rod or a top cap of the sub-rivet, the upper portion of the sub-rivet is in sleeved relation with the female rivet and is in pressing connection relation with the clamping plate, and a self-tapping section at the lower portion of the sub-rivet is in connection relation with bone, namely, three-point connection relation is achieved.

The utility model provides an external fixation frame female nail of being applied to claim, includes female nail and son nail, female nail includes the female nail cap portion at nail body, lower segment female nail self tapping section and middle part, son nail includes the son nail self tapping section and the son nail cap portion of nail body, lower segment, is provided with the notch in the eccentric position of female nail cap portion, and this notch is in the same place with the nail body or the son nail cap portion matching suit of son nail.

In the primary-secondary nail, further, the lower end of the rod body of the primary-secondary nail is a self-tapping section used for screwing in bone, the upper section is provided with primary-secondary nail external threads, a notch internal thread is arranged in a notch of a cap part of the primary-secondary nail, and after the primary-secondary nail is assembled with the primary-secondary nail, the primary-secondary nail external threads and the notch internal threads can be connected together through threads, so that the primary-secondary nail can be prevented from retreating outwards.

In the primary and secondary nails, the cap part of the primary nail or the secondary nail is further prolonged to be of a cylindrical structure, and the cylindrical cap part is sleeved in the nail penetrating round hole of the clamping plate and the composite nail penetrating hole for fixation.

In the primary-secondary nail, a step groove is further formed in the notch of the primary-secondary nail, the part with the smaller diameter of the step groove is used for sleeving the rod part of the primary-secondary nail, and the part with the larger diameter of the step groove is used for sleeving the cap part of the primary-secondary nail.

The utility model has the following beneficial effects: the primary and secondary nail has high structural strength and small processing difficulty, and the self-tapping sections of the primary and secondary nails are respectively screwed into the bone, so that the connection strength and the anti-rotation strength between the nails and the bone are improved. The lower ends of the primary and secondary nails are respectively provided with a self-tapping section, so that the primary and secondary nails can be independently screwed into bones, and the primary and secondary nails are mutually matched to play a high-strength connection anti-rotation function.

The external fixing frame with the primary and secondary nails is adopted in the embodiment, so that the two ends of the fracture are respectively provided with the single primary and secondary nails, and the external fixing frame is suitable for the condition that the span of a fracture area is small and the fixation of multiple nails cannot be realized. The external frame structure is simplified as much as possible, but the strength of the female nails (main nails) is not changed, and the female nails can be ensured not to rotate in the bone.

The external fixing frame disclosed by the utility model has a simple structure, can reduce the traumata of a patient caused by an operation as far as possible, can reduce the volume and the weight of the external support in the rehabilitation period of the patient, improves the mobility and the flexibility of the patient in the rehabilitation period, reduces the compression of the external support on the fracture part, and is beneficial to recovery.

The external fixing frame is simple in positioning operation, and can finish operation only through simple training and learning, so that the operation workload is simplified, and the operation cost is reduced.

The external fixing frame has the advantages of simple and practical structure, low manufacturing cost and medical cost reduction. Fewer structural components provide ease of sterilization and maintenance handling. Not only is easy to install, but also is easy to remove.

Drawings

Fig. 1 is a standard state perspective view of the external fixator of the utility model.

Fig. 2 is a view of a structure of the male and female nails applied to fig. 1.

Fig. 3 is a front view of fig. 2.

FIG. 4 is a schematic illustration of the assembly relationship of the neutron of FIG. 3.

Fig. 5 is an end view of fig. 2.

Fig. 6 is another primary and secondary staple assembly relationship.

Fig. 7 is a diagram of yet another snap-pin assembly relationship.

Fig. 8 is a structural view of the splint of fig. 1.

Fig. 9 is a structural view of another splint.

Reference numerals in the drawings: the connecting rod 1, the primary and secondary nails 2, the primary and secondary nail cap parts 21, the notch 22, the notch internal threads 23, the primary nail self-tapping section 24, the clamping plate 3, the head clamping plate 3a, the tail clamping plate 3b, the nail rod perforation 31, the locking seam 32, the nail penetrating round hole 33, the convex-concave anti-skid pattern 34, the locking female 4, the screw 5, the shaft seat anti-skid pattern 6, the plane 7, the shaft seat 8, the secondary nail 10, the secondary nail cap part 11, the secondary nail external threads 12 and the secondary nail self-tapping section 13.

Description of the embodiments

Example 1: the prior external fracture fixing frame is applied by respectively and vertically driving at least two fixing nails at two sides of the fracture, wherein the exposed end of each fixing nail is respectively provided with a universal joint, and the adjacent universal joints are fixed through connecting rods. Because the nailing position can be moderately eccentric, four female nails are difficult to be connected in series through one connecting rod, connecting rods are needed to be arranged between two adjacent fixed nails in the prior art, and the nails are fixed through universal joints. The external fixing mode has a plurality of connecting rods with inconsistent directions, and all universal joints are required to have the adjusting relation of transverse rotation and locking and vertical rotation and locking, so that the whole external frame is relatively large in volume, and a fracture patient is inconvenient to carry after being installed and used, so that the patient cannot wear and change clothes, and the involved activities are affected. The present embodiment provides an outer frame structure that is simplified as much as possible, but does not change the strength of the female nails (main nails), and can ensure that the female nails are not rotated in the outer frame and in the bone, and the outer frame can achieve the simplification effect as shown in fig. 1 after being applied.

Example 1: a single-rod primary-secondary nail external fixing frame containing primary-secondary internal and external anti-rotation reinforcing nails as shown in figure 1 can be seen from the figure: the outer frame mainly comprises a head end clamping plate 3a, a tail end clamping plate 3b, a connecting rod 1, a head terminal female nail, a tail end male and female nail, a screw 5 and a locking nut 4. Compared with the existing external fixing frame, the structure is obviously simplified, and the number and the volume of the external fixing frame are about 1/3 of the number and the volume of the existing external fixing frame. Compared with a fixing frame with the publication number of CN212307999U, the primary and secondary nails have high structural strength and small processing difficulty, the self-tapping sections of the primary and secondary nails are respectively screwed into the bone, and the connection strength and the anti-rotation strength between the nails and the bone are improved.

Wherein, the primary and secondary nails comprise a primary nail 2 and a secondary nail 10, the primary nail 2 comprises a nail body, a lower-section primary nail self-tapping section 24 and a middle primary nail cap part 21. The sub-nail 10 comprises a nail body, a sub-nail self-tapping section 13 at the lower section and a sub-nail cap part 11. As can be seen in fig. 2, a slot 22 is provided in an eccentric position of the female pin cap portion 21, which matches the pin body or the male pin cap portion of the male pin. Fig. 2 shows a configuration of the combined primary and secondary nails.

Application of the primary and secondary nails to an external fixation frame as shown in fig. 1, the head clamp plate 3a of the external fixation frame allows the connecting rod 1 to rotate and lock up in the lateral plane, and the tail clamp plate 3b allows the connecting rod 1 to adjust in the axial direction and allows the tail terminal primary nails to rotate in the longitudinal plane.

The peripheral surface of the self-tapping section of the primary-secondary nail is distributed with spiral blades which can be screwed into bone and form spiral holes. The female staple 1 occupies a major portion of the combined cylindrical body and the male staple 10 occupies a minor portion of the combined cylindrical body. The female nails are the primary connecting parts and the male nails are the secondary connecting parts, but the male nails can lock the female nails.

The existing external fixation frame female nail applied to fracture mostly has the condition that the self-tapping of the lower end is not provided with a self-locking structure, and the external fixation frame female nail is not suitable for being independently applied, namely, the external fixation frame female nail is not suitable for being fixed by only adopting a single nail at two sections of fracture respectively, the fixing frame of CN212307999U is provided with the self-locking structure, but the mode that the external fixation frame female nail is combined into a cylindrical structure and the upper end and the lower end of the external fixation frame female nail are connected in a split manner is obviously different, the lower ends of the primary and secondary nails of the embodiment are respectively provided with the self-tapping sections, so that the self-tapping sections of the primary nails and the self-tapping sections of the primary nails can be independently screwed into bones, and the primary and secondary nails are mutually matched to play the anti-rotation function of high-strength connection. The anti-rotation strength of the fixing frame of the CN212307999U is obviously not comparable with that of the fixing frame of the CN212307999U, and under the conditions of large activity and high strength, the scheme still has the possibility of two sections of spin of fracture, so that the butt joint position is possibly loosened or separated, the processing difficulty of the fixing nail is large, and the strength of the fixing nail is low. When the primary and secondary nails are adopted in the embodiment, the primary and secondary nails are cylindrical, the processing difficulty is small, after a single primary and secondary nail is implanted into a fracture section, the primary and secondary nails cannot rotate relative to the fracture section, namely, the single primary and secondary nail and the fracture section are in locking relation, so that the fixation of one fracture section can be achieved by only the single primary and secondary nail, and the primary and secondary nails adopted in the embodiment cannot be reversed after bone implantation, so that the loosening problem is thoroughly solved.

The embodiment adopts the double-nail external fixation frame, so that the two ends of the fracture are respectively provided with a single nail, and the double-nail external fixation frame is suitable for the condition that the span of the fracture area is small and the fixation of multiple nails cannot be realized.

As can be seen from fig. 1, the application of the embodiment can realize the self-locking function of the single nail, and the single nail can be directly applied to a section of fracture, and no rotation possibility exists between the female nail and the bone. When the locking nail in the example is applied, the female nail 2 can be directly screwed into the bone by a drilling tool, and then the male nail 10 is pressed into the gap along the center of the notch and axially. Therefore, the cap parts of the sub-nails and the female nails are connected with each other, but the self-tapping sections of the sub-nails and the female nails are respectively and independently screwed into the bone, so that an anti-rotation effect is formed.

It can be seen that the head terminal female nail is vertically sleeved in the nail penetrating round hole 33 of the head end clamping plate 3a, the tail end sub-female nail is vertically sleeved in the nail penetrating round hole 33 of the tail end clamping plate 3b, the female nail 2 plays a main connection fixing role, the mounting of the sub-nail 10 can prevent the loose problem of the fixing position of the female nail 2 caused by the back-rotation and withdrawal, the head end clamping plate 3a and the tail end clamping plate 3b respectively clamp the head terminal female nail and the tail end sub-female nail, and the female nail 1 and the sub-nail 10 of the combined nail are clamped and combined into a whole.

It can also be seen in fig. 1 that the head end of the rod body of the connecting rod 1 is provided with a shaft seat, the center of the shaft seat is provided with a shaft hole, and the tail end of the rod body is provided with a screw rod section. The shaft seat and the shaft hole can realize transverse surface rotation adjustment, and the screw rod section can realize axial adjustment and longitudinal surface rotation adjustment. Thereby realizing three-dimensional adjustment, and being used for adapting to the possible arbitrary forms of the head terminal female nails and the tail terminal male and female nails. The middle part of the connecting rod 1 is plate-shaped, the left end of the connecting rod is provided with a baffle, the right end of the connecting rod is plate-shaped, a plane 7 is arranged, and the connecting rod is transited to the shaft seat 8, so that a joint plane exists between the end face of the shaft seat 8 and the clamping plate.

As shown in fig. 8, the overall structure of the splint is U-shaped, with a trough bottom and two sidewalls. Wherein, the tank bottom is provided with a through-pin round hole 33, two side walls of the through-pin round hole penetrate through a pin rod through hole 31, a fit clearance between the two side walls of the through-pin round hole is a locking seam 32, and the diameter of the through-pin round hole 33 is larger than the width of the locking seam 32.

The screw rod penetrates through the shaft hole to fix the head end of the connecting rod 1 with the head terminal female nail, and the screw rod section penetrates through the nail rod perforation 31 of the tail end clamping plate 3b to be fixed. It can be seen that convex-concave anti-slip patterns are provided around the two outer sidewall shank perforations 31 of each clamping plate to enhance the degree of stability between the components after connection. It is also possible to provide the screw hole 33 of each clamping plate with convex and concave patterns along the axial direction or to provide the convex and concave patterns on the outer sides of the primary and secondary screws for improving the locking degree between the clamping plate and the primary and secondary screws.

Based on the above scheme, the special frame of the embodiment can adapt to the possible arbitrary forms of the head terminal female nails and the tail terminal male and female nails when being applied. After the two sections (the far section and the near section) of the fracture are respectively implanted with the combined nails, the two nails are implanted without assistance of an auxiliary positioning tool, only the two combined nails are controlled to be blindly printed in the range of one side of the bone, the two combined nails are adapted to the two clamping plates at the two ends through the connecting rod 1, the screw rod and the locking wire are screwed after the adaptation is adjusted, the operation is simple, the portable and the storage are convenient, the wound surface is small, and the external structure is simple and easy to accept by a patient.

Example 2: on the basis of the embodiment 1, a primary-secondary nail structure shown in fig. 3-5 is adopted, and the difference from the embodiment 1 is that the primary-secondary nail cap at the upper part of the primary nail in the embodiment has the same diameter as the nail body, and the primary-secondary nail cap at the upper part of the primary nail has a smaller notch 22.

Example 3: based on embodiment 1, the lower end of the rod body of the sub-nail is designed to be a self-tapping section for screwing in bone, the upper section is provided with a sub-nail external thread 12, as shown in fig. 6, a notch internal thread 23 is arranged in a notch 22 of a nut cap 21, and after the sub-nail is assembled with the nut, the sub-nail external thread 12 and the notch internal thread 23 can be in threaded connection together, so that the sub-nail can prevent the nut from withdrawing outwards.

Example 4: further on the side of the nail penetration hole 33 of the splint 3, a composite nail penetration hole 35 is provided as shown in fig. 9, on the basis of embodiment 1 and embodiment 2. The composite through-hole 35 is used for sheathing and pressing the shank or top cap of the sub-nail. Thus, the upper part of the sub-nail in this embodiment has not only a sleeved relationship with the main nail but also a pressed connection relationship with the clamping plate 3, and the self-tapping section of the lower part of the sub-nail has a connection relationship with bone, namely a three-point connection relationship.

Example 5: on the basis of the above embodiments, the cap part of the female nail or the male nail can be extended to be a cylindrical structure, and the cylindrical cap part is sleeved in the nail penetrating round hole of the clamping plate 3, namely, the composite nail penetrating hole for fixing. For example, after the cap part of the female nail is extended to be cylindrical, the cap part is sleeved in the through nail round hole of the clamping plate 3, an open or closed notch is formed in the cap part, the male nail is matched and sleeved or fixed in the notch, and the lower ends of the male nail and the female nail are connected with bones.

On the basis of the above embodiments, other variants of the above embodiments are also possible and are not described in detail. Compared with the structure of a plurality of connecting rods and a plurality of universal joints of the prior external fracture fixing frame, the embodiment is also provided with a step groove 36 in the notch of the female nail, as shown in fig. 7, the part with smaller step groove diameter is used for sleeving the rod part of the sub-nail, and the part with larger step groove diameter is used for sleeving the cap part of the sub-nail.

Claims

1. The single-rod primary-secondary-nail external fixation frame comprises a head end clamping plate (3 a), a tail end clamping plate (3 b) and a connecting rod (1), and is characterized by further comprising a head and tail terminal primary nail, wherein each primary-secondary nail comprises a primary nail (2) and a secondary nail (10), the primary nail (2) comprises a nail body, a lower-section primary-nail self-tapping section (24) and a middle primary nail cap part (21), the secondary nail (10) comprises a nail body, a lower-section secondary-nail self-tapping section (13) and a secondary nail cap part (11), a notch (22) is formed in the eccentric position of the primary nail cap part (21), the notch (22) is matched and sleeved with the nail body or the secondary nail cap part of the secondary nail (10), the clamping plate is U-shaped, a through nail round hole (33) is formed in the bottom of the clamping plate, two side walls of the clamping plate are penetrated and provided with nail rod through holes (31), a matching gap between the two side walls of the clamping plate is a locking joint (32), and the diameter of the through nail round hole (33) is larger than the width of the locking joint (32); the head end of the rod body of the connecting rod (1) is provided with a shaft seat, the center of the shaft seat is provided with a shaft hole, and the tail end of the rod body is provided with a screw rod section.

2. The external single-rod primary-secondary nail fixing frame according to claim 1 is characterized in that convex and concave patterns along the axial direction are arranged in the nail penetrating round holes (33) of each clamping plate, or convex and concave patterns are arranged on the outer sides of the primary-secondary nails, so as to improve the locking degree between the clamping plates and the primary-secondary nails.

3. The single-rod primary and secondary nail external fixation frame according to claim 1, characterized in that convex-concave anti-slip patterns are arranged around the two outer side wall nail rod perforations (31) of each clamping plate.

4. The single-rod primary-secondary nail external fixation frame according to claim 1, characterized in that a composite nail penetrating hole (35) is arranged on the clamping plate, the composite nail penetrating hole (35) is used for sleeving and pressing a nail rod or a top cap of a secondary nail, so that the upper part of the secondary nail is not only in sleeved relation with the primary nail, but also in pressing connection relation with the clamping plate (3), and a self-tapping section of the lower part of the secondary nail is in connection relation with bone, namely in three-point connection relation.

5. Be applied to primary and secondary nail of external fixation frame of claim 1, characterized in that includes female nail (2) and son nail (10), female nail (2) are including nail body, the female nail cap portion (21) of the female tapping section (24) of hypomere and middle part, son nail (10) are including nail body, the son nail self tapping section (13) of hypomere and son nail cap portion (11), are provided with notch (22) in the eccentric position of female nail cap portion (21), and this notch (22) is in the same place with the nail body or the son nail cap portion matching suit of son nail (10).

6. The primary-secondary nail according to claim 5, characterized in that the lower end of the shank of the primary-secondary nail is a self-tapping section for screwing into bone, the upper section is provided with a primary-secondary nail external thread (12), and a notch internal thread (23) is arranged in a notch (22) of the primary-nail cap (21), and when the primary-secondary nail is assembled with the primary-nail, the primary-nail external thread (12) and the notch internal thread (23) can be connected together in a threaded manner, so that the primary-secondary nail can be prevented from being withdrawn outwards.

7. The primary-secondary nail according to claim 5, characterized in that the cap of the primary nail or secondary nail is prolonged to a cylindrical structure, and the cylindrical cap is sleeved in the nail penetrating round hole and the composite nail penetrating hole of the clamping plate (3) for fixation.

8. The primary-secondary nail according to claim 5, characterized in that a stepped groove (36) is also provided in the slot of the primary nail, the portion of smaller diameter of the stepped groove being used for housing the shank of the secondary nail, the portion of larger diameter of the stepped groove being used for housing the cap of the secondary nail.