" BUTTRESSING/ANTIGLIDE AND NEUTRALISATION PLATE FOR DISTAL MEDIAL FEMUR FRACTURE FIXATION AND FOR PERIPROSTHETIC FRACTURE IN TOTAL KNEE REPLACEMENT "

Abstract

The present invention provides a fixation system for providing buttress for the distal medial femur fractures and for mechanically supporting the fracture fixation in the distal femur and for periprosthetic fracture in total knee arthroplasty. The system comprises of a region specific locking plate matching with distal medial side of femur and fixation screws. Locking plate comprises of a head and shaft region, where head has a plurality of three variable angle locking holes with four threaded columns in the width direction of head and shaft region has a plurality of three locking hole on the distal side of the shaft and a plurality of 2/4/6 combination holes after the locking holes along the length direction of the shaft. Plurality of two k wire holes are provided, one hole on the junction of head and shaft and on the extreme proximal end of the shaft just below the last combination hole. The variable angle locking holes includes four threaded columns separated by a common one of the recess. The adjacent ones of columns can be referred to as circumferentially adjacent ones of the columns. The threaded columns and recess define circumferential centrelines that extend along planes that intersect the central hole’s axis. The wavy edges which comprises of concave and convex portion enables the surgeon the make minor contouring to plate if needed. The plurality of 2/4/6 combination holes and four threaded columns in variable angle locking hole along with the anatomically contoured plate enables good buttressing and fixation for the distal side fractures, supporting to other distal medial fracture fixations and for periprosthetic fractures occurred after total knee arthroplasty.

Specification

Description:The following specification particularly describes the nature of the invention and the manner in which it is to be performed:

FIELD OF INVENTION

The present invention relates to a device used for buttressing/antigliding/neutralising mode of fixation for fractures of the distal medial region of femur and in combination supporting the intramedullary nail or the lateral plate fixation and for periprosthetic fracture in total knee replacement.

BACKGROUND OF INVENTION

Femur is one of the important bones in our body which takes part in formation of the hip joint proximally and the knee joint distally. Thus the lower end of the femur provides the articulating surface of the knee joint. The incidence rate of fracture on the femur is also high compared to other bones. Femur is curved anterolaterally, and common deformity that happens in knee is Varus. Because of these reasons the line of weight bearing passes more through the medial cortex and medial condyle of femur. The conventional mode of fixation with the lateral distal femur locking plate showed a high percentage of complications in case where the medial cortical contact was less or where there was severe affection of the medial condyle (AO Type 33.C3). To counter this problem, it is observed that, if an implant is used to substitute or support the medial pillar the chances of complications reduced. As the osteoporosis cases that are rising in number are another major concern in the fracture fixation and healing. The duration of placement of the implants inside the body also increases due to this.
Surgical time which is one of the major crucial part needs to be reduced, for improved patient safety and the avoidance of infection. The contouring of the plate according to the anatomy of the patient needs to be done by the doctor. Increased effort for the doctor and more time consumption for the surgery are an important concern for this. An invention which is precountoured, minimise the time and effort required intraoperatively to fix theses kind of fractures.
According to the complexity of the fracture the methods, the fixation plates, load bearing, surgical time etc. will vary. Among this AO-33C3 is the most challenging one and there are no proper precountoured, region specific fixation plates which can give a proper anatomical contour, buttressing effect and properly aligning or matching with other fixation devices. Though the lateral plate provides a very good modality for fixation of distal femur fractures, they at times are not good enough for fractures involving the medial column (AO 33.C3). Along with this this the load bearing capability or the number of cycles withstand by the fixation implants will also be less. The nonunion of fractured bones, the early failure of the fixation plates, unevenness in the fracture healing and stress concentration are usual in AO-C3 fractures.
For fixation of the fractured bones different kinds of fixations are used according to the type of fracture. Intramedullary nail and fracture fixation bone plates are the most common among them. For the distal femur fracture, other than high end femur fractures lateral plates are used. According to the severity of the fracture the nails and plates are used alone or in combination. Generally, in case of AO- 33C3 fractures, the plates are used in lateral and medial side of the femur bone along with an intramedullary nail. In case of 33.A3 and 33.B3, a lateral plate or an intramedullary nail in isolation is sufficient.. But the major problem arises regarding the load bearing and the plate life. Multiple cases are being reported regarding the failure of lateral fixation plates of femur. For arresting the complete degrees of freedom of the fracture fragments and avoiding the fracture of bone plates and the nail, necessity of distal medial plates occur.
Total knee arthroplasty(TKA) are rising and periprosthetic distal femur fracture after TKA usually can be operated by intramedullary nailing, plating or revision arthroplasty. Lateral femur plates have been using widely, but if fractures extend too distal over the proximal border of femoral component, difficulty of fixing the fractures increases. The interference of the bone, prosthesis and the plate screws lead to poor fixation. The screws or anchors need to be adjusted according to the prosthesis also.
There are very less distal medial plates available which are ideal to use. Surgeons usually use general plates and contour them during surgery to fit with the distal medial portion of bone. This increases the surgical time and effort of surgeon. Improper and misaligned screws are also an issue. The buttressing effect is also not properly met in this condition.

PRIOR ARTS AND ITS DISADVANTAGES

There are various inventions related to the present invention but none satisfies the objects of inventions laid down by the present invention:
A Chinese patent CN202490018U consist of distal side inner locking plate comprising of a head portion and shaft with locking holes and combination holes respectively. The locking holes are arranged in diamond shape.
There are many drawbacks with this invention including the femur fracture fixation range, simple locking holes which makes a rigid fixed direction for the screw which can interact the fixation of lateral plates.Non-anatomically contoured thick plate structure increases the surgical time and effort of surgeon.
Another patent CN207101351U consist a kind of fixing device of distal femur comprising a main lock plate being fixed on the outside of distal femur and the auxiliary lock fixed board being fixed on the inside of distal femur. The main lock consisting of head and cadre with multiple locking holes. Auxiliary locking plate with stripes connected with crooks consisting of multiple locking holes.
There are many drawbacks with this invention including, the non-anatomic nature of the plate, the fixed direction fixation of the screws, difficulty in contouring by the doctors due to the thickness which increases the surgical time.
Another patent US 20150005831A1 consist of distal medial femur bone plate system, comprising of a bone plate and method of use, contoured to fit above the medial epicondyle that provides numerous apertures for fixation to the distal femur with an offset screw design to allow the screws around nail or with a lateral distal plate.
For the above prior art even if the objective is moreover similar,the attaining of the objective has many limitations. The 7 holes arranged in the distal portion of the medial plate will not cover the proper area and increase complexity. The polyaxial position of the apertures in the elongated shaft region of the plate reduces the scope of minor contouring according to different human anatomies, increase the complexity in operation, stress concentration and increase in thickness. Even if the plates are precontoured, the anatomical fixation and allowances given for attaining the minor change according to patient is less.
Another patent CN215349376U relates to a locking plate for fixing the distal femoral comminuted fracture, comprising of head and a shaft part which is anatomically matching with the distal femur. The contour and provision for the minor bending is also provided with simple locking screw holes.
The said above prior art model is an inspiration for making the invention. The contouring and outer shapes are suitable for the human anatomy. But the major limitation for the above prior art consist of the simple locking screw holes, which reduces the scope of varying the screw angles according to the lateral plate screws and applying them for the fixing of periprosthetic fracture for total knee arthroplasty. The length of the plate or specifically saying ,the 5 holes in the stem region is not having the functionality to cover all types of fracture that occur in the distal region of the femur. The proper buttressing effect is impossible to get for the AO-33C3 fractures. The non-provision of the variable screw holes causes the increased effort for surgeon to fix the plate with the lateral side plate and for using it for fixing the periprosthetic fractures of total knee arthroplasty. Since the provision of support plate for the other fixation is not given and entire focus is on fixation of the bone fragments by using the plate alone, then the increase in thickness and width, makes the plate of a bigger profile, which becomes more prominent subcutaneously in, over the medial condyle of the femur.


OBJECTS OF PRESENT INVENTION

The primary object of the present invention is to provide an anatomically fit additional plate for osteosynthesis for all types of distal medial femur fractures in the buttress/antiglide/ neutralisation mode.
Another objective of the present invention is to provide a distal medial femur plate which can be used in conjunction with any type of distal femur fixation system and as a supporting plate which carries a part of load, so as to decrease the chance of failure of implants inside body.
Another objective of the present invention is to provide a plate which has the provision of adjusting the direction of the screws in the distal region of the plate for avoiding the interference with lateral plate screws and for attaching with the total knee replacement prosthesis on the distal side of femur in periprosthetic fractures.
Yet another object of the present invention is to provide a new and improved bone plate system in the distal medial region of femur which provides advantages of prior art and overcoming the disadvantages associated with them.


Fig.01 : Oblique view of present invention
Fig.02 : Top view of plate
Fig.03 : Front view of plate
Fig.04 : Types of screw systems
Fig.05 : Variable angle locking screw hole
Fig.06 : Angular orientation of a variable angle locking screw with variable angle screw hole
Fig.07 : Combination hole
Fig.08 : Attachment of present invention with lateral side plate and femur
Fig.09 : Attachment of present invention with intramedullary nail
Fig.10 : Attachment of present invention with lateral plate and total knee arthroplasty part in femur
DESCRIPTION OF DRAWINGS


Meaning of Reference numerals
1 : Variable angle locking holes
2 : locking hole
3 : Combination hole
4 : Krischner wire holes
5 : Wavy structure/concave portion in edges of head
6 : Wavy structure/concave portion in lateral sides of shaft
7 : Head part of plate
8 : Shaft part of plate
9 : Distal medial femur plate
10 : Locking screw
11 : Cortical screw
12 : Variable angle locking screw
13 : Threaded column in variable angle locking hole
14 : Recess in variable angle locking hole
15 : Axis of variable angle locking hole
16 : Axis of locking hole
17 : Locking thread on combination hole
18 : Cortex screw head attachment portion in combination hole
19 : Lateral side femur plate
20 : Femur bone
21 : Intramedullary nail
22 : Total knee arthroplasty implant part in distal femur


SUMMARY OF INVENTION

The present invention comprises a plate (9), conforming to anatomical form of inner side of distal femur, for buttressing the distal medial fracture, which is used along with the fracture fixation systems (19,21,22) of distal medial femur for giving a support or stabilization for the systems and the screws for attaching the plate (9) to the fracture fragments or the bone. It may also be used alone in cases of isolated medial hoffa fractures (Coronal Plane) of the medial side.
Said invention consists of plate (9) made of materials such as but not limited to Ti6Al4V, all other types of biocompatible titanium and stainless steel alloys and so forth. The said plate can have a length ranging from 83.5 mm to 144 mm according to the type of fracture fixation it is used for. The said plate (9) has a width of 28 mm in the head part (7), with a thickness of 3-3.1 mm and a width of 10-10.2 mm in the shaft part (8) and a thickness of 3-3.1 mm. Referring to the embodiments as shown in fig.01 to fig.03, said plate (9) comprises of a head portion (7) on the distal end and a shaft region (8) heading to proximal part of the plate.
The said head portion (7) consists of at least 3 variable angle locking holes (1) with four threaded columns (13) inside hole size, positioned on same horizontal line (H), for attaching variable angle locking screws (12). The 4 pillar variable angle locking hole (1) gives the provision for the variable angle locking screw (12) to align 0° to 15° from the screw axis in 4 perpendicular directions as shown in fig.06.
The said shaft region (8) consists of two different plurality of apertures, a plurality of three locking holes (2) on the distal side of the shaft (8) and a plurality of combination hole (3) of locking (17) and cortical screw holes (18), in a range of 2/4/6 according the fracture type, after the set of simple locking hole (10) in the distal part of shaft (8) arranged in straight line hole size. The axial direction of the simple locking hole and axial direction of combination holes are arranged in non-parallel mode
Furthermore, the outer edge of the plates near to the variable angle locking holes in the head region (7) and the shaft region (8) have convex parts outwards (5) to the width direction in the head part and concave part (6) along the width direction of the shaft.
Furthermore, a first kirschner wire hole (4) is formed in the junction of head(7) and the shaft part(8)
Furthermore, a second kirschner wire hole (4) is formed below the last combination hole (3) on the proximal part of the shaft (8). These provide the function of temporary fixation of the plate (9) with K wires during the surgery.
The pre contouring of the plate (9) according to the anatomy of the distal medial portion of the femur (20) enables the surgeon to reduce the surgical time and effort. Four threaded column (13) variable angle screw holes (1) enable the surgeon to fix the variable angle locking screws (12) according to the alignment of the other plate fixation systems in the femur (19), particularly the lateral plates in the femur (20), intramedullary nails (21) and total knee replacement prosthesis (22). The 7 hole or 9-hole shaft (8) in the plate (9) enables the perfect buttressing for most of the fractures in the distal region of the femur. The perfect attachment with all types of fixation systems, in the distal region of the femur, distribute the load to the present invention and hence avoid the failure of the implants.



DETAILED DESCRIPTION OF DRAWINGS

The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
It is to be understood that the term "comprising" or "comprises" used in the specification and claims refers to the element of the invention which comprises X, Y, and Z, which means that the invention might have other elements in addition to X, Y, and Z. For example, their invention could include A, B, and/or C as long as it also has X, Y, and Z.
Referring to the embodiments in fig.01-fig.10 the present invention is a buttressing plate for all types of distal medial femur fractures and a stabilization or strengthening system for all types of fixation systems in the distal medial femur.
The design of the said invention is such that it matches the anatomy of the distal medial region of the femur (20). Said system is particularly used in conjunction with intramedullary fixation (21) or lateral side plate (19) for femur and not recommended to use alone for AO type 2 or 3 fractures. Furthermore, the plate will increase the load bearing ability of the fixations and reduce the chance of failure of implants.
Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings, however, it is to be understood that the disclosed embodiments are merely examples of disclosure, which may be embodied in various forms.
For present embodiment, referring to the fig.01 and fig.02, consists of following parts:
• A proximal shaft (8)
• A distal head (7)
• 3 variable angle locking holes with four threaded columns (1)
• 3 locking holes (2)
• 4 combination holes of simple locking and cortex (3)
• 3 variable angle locking screws (12)
• 3 locking screws (10)
• 4 cortical screw (11) / locking screw (10)
The said invention has plate made up of, but not limited to, Titanium alloy-Ti6Al4V, having a width of 28.2 mm in the head (7) and maximum width of 10.2 mm in the shaft region (8). 3-3.1 mm thickness for both head (7) and shaft region (8) with shape and curvature making it fit anatomically to distal medial side of femur. The total length of the present embodiment is 113.5 mm. The head portion (7) and the shaft portion (8) form a substantially "T" shaped structure and they are fixedly connected together in an obtuse angle, such as the angle is in range of 102°-105° between the horizontal axis(H) of the head portion (7) and longitudinal axis (L) of shaft (8). With refer to fig.02 for the present embodiment this angle is 102.5°.
For the present embodiment, referring to the fig.01 and fig.02 the outer edge of the plate (9) has wavy structure. A concave edge is between the adjacent holes and the width between two opposite adjacent concave edge (6) is 7-7.2 mm in shaft (8) region. The width of the shaft (8) in the centreline of locking holes (2) and combination holes (3) is 10-10.2 mm. The structure provides provision for contouring the plate according to the patient anatomy.
According to the embodiments shown in fig.01 the head region (7) of the construct (9) has a plurality of 3 variable angle locking holes (1) arranged in the width direction of the plate (9) and the shaft region (8) of the construct (9) has a plurality of 3 locking holes (2) near to the head section (7) and a plurality of 4 combination hole (3) arranged in length direction to the proximal part of the shaft (8).
For the present embodiment includes two k wire holes (4) of diameter 1.5 mm. First K wire hole on distal side of shaft (8) and second hole just below along the length direction of last combination hole (3) on the proximal part of the shaft (8). The K wire holes (4) determines the depth and direction of the locking nail and temporarily fix the locking plate to the body.
Furthermore, owing to said variable angle locking holes (1), it includes four recesses (14) that are circumferentially spaced apart from each other. Each of the recesses are substantially identical to each other. Furthermore, the recesses (14) are equidistantly spaced from each other about the central hole axis (15). Furthermore, the embodiment (1) includes four threaded columns (13) separated by a common one of the recess (14). The adjacent ones of columns (13) can be referred to as circumferentially adjacent ones of the columns (13). The threaded columns (13) and recess (14) can define circumferential centrelines that extend along planes that intersect the central hole's axis (15). The circumferential centrelines of the columns can be circumferentially offset from circumferential centrelines of the recess (14) by 45 degrees. Each of the threaded columns (13) includes a thread matching with the profile of head of variable angle locking screw (12). Now referring to fig.06, central axis of the variable angle locking screw (12) makes a 30-degree cone with the axis of the hole (15), which gives the provision for the screws to align or adjust with the screws of lateral plate (19) or intramedullary fixations (21).
Furthermore, owing to the said simple locking holes (2), it includes thread profile matching with the thread profile of head of the locking screws (10). The threaded portion can define circumferential centrelines that extend along planes that intersect the central hole's axis (16).
Furthermore, referring the fig.07, the combination holes (3) includes a threaded portion (17) on the distal side and cortex hole (18) on the proximal part of the combination screw hole (3). For the present embodiment, the combination hole (3) can accept a 3.5 mm locking screw (10) or 3.5 cortical screw (11).
According to the embodiments of the present invention, the said invention can anatomically fit to the distal medial section of the femur (20) which gives a perfect buttressing to the fractures. The variable angle locking screw holes (1) with, four threaded columns (13), provides provision for the anchors (12) more angular movement from the central axis (15) of the screw holes and this enables a perfect fixation without interference with the lateral side femur plate (19) screws. The 3 locking holes (2) and 4 combination holes (3) enables the plate to cover all levels of fractures in distal side of femur and to give the sufficient mechanical strength to other fixations of femur by carrying a part of load. Even if, 3-3.1 mm thickness of plate reduce the load bearing capacity of the plate and makes it not suitable for fixing the fractures, except in isolated Hoffa Fractures/Coronal Plane fracture of the medial condyle, without the aid of other fixations, it avoids the impinching of the plate (9) and proper fixation of plate (9) to femur bone (20).

ADVANTAGES OF THE PRESENT INVENTION

The present invention has multiple advantages over the prior art.
The present invention is a buttressing plate for all types of AO fractures in distal medial femur portion of the bone, which can be used in conjunction with any intramedullary hip nails and lateral plates for femur.
The present invention is a neutralisation plate which carry a part of load in the distal medial section of the femur when it is in conjunction with the lateral plates or the intramedullary nail and thereby reducing the chance of failure of the femur fixation implants.
The present invention gives the variability for the distal portion locking screws to lock in 4 different directions with the aid of 4 -threaded column variable angle locking holes.
The present invention can be used in conjunction with the implant attached in the distal femur as a part of the total knee replacement prosthesis for arresting the periprosthetic fractures.
, C , C , Claims:We claim,
1. A fixation system for providing buttressing for all types distal medial femur fracture segments and mechanically supporting the fracture fixations for distal femur, wherein the same consists of:
- locking plate body (9) comprising of a proximal shaft (8) and distal head (7)
- 3 variable angle locking holes (1) with four threaded columns (13)
- 3 simple locking holes (2)
- 2 /4/6 combination holes of simple locking and cortex (3)
- 3 variable angle locking screws (12)
- 3 locking screws (10) and
- 4 cortical screw (11) / locking screw (10)
The locking plate body (9) is in accordance with the anatomical form of the distal medial side of femur comprising of a head (7) and a shaft (8), where the head is provided with a plurality of three variable angle locking holes(1) with four threaded columns (13) and the shaft(8) is provided with a plurality of three locking holes(2) on the distal side of the shaft and a plurality of two or four or six combination holes(3) on the proximal side of the shaft (8), where the holes in shaft are aligned in length axis of the shaft and screw holes in head are arranged along width direction of head
2. The fixation system as claimed in claim 1, characterized in that, the plate body (9) of Titanium alloy-Ti6Al4V or stainless steel alloy-SS316, SS316 LVM or any other biocompatible material

3. The fixation system as claimed in claim 1, characterized in that, the plate body (9) has a thickness of 3.1 mm

4. The fixation system as claimed in claim 1, characterized in that, the variable angle locking hole (1) has 4 threaded columns (13) matching with the thread profile of variable angle locking screw (12) head thread, which enables the screw to fix in 4 different direction and lock within a cone of 30 degree

5. The fixation system as claimed in claim 1, characterized in that, the variable angle locking holes (1) can accommodate the variable angle locking screw (12), locking holes (2) as claimed in claim 1 accommodate the locking screw (10) and combination screw holes (3) as claimed in claim 1 in shaft (8) accommodate locking screw (3) or cortical screw (11)

6. The fixation system as claimed in claim 1, characterized in that, the head portion (7) and the shaft portion (8) form a substantially "T" shaped structure and they are fixedly connected together in an obtuse angle, such as the angle is in range of 102°-105° between the horizontal axis (H) of the head and the longitudinal axis (L) of the shaft


7. The fixation system as claimed in claim 1, characterized in that, plate (9) has edges curved inward between two adjacent holes and this forms a wave like structure on head (5) and a wave like structure on shaft (6) consisting of concave and convex edges

8. The fixation system as claimed in claim 1, characterized in that, plurality of two kirschner wire hole (4), with first one is formed in the joint of head (7) and shaft portion (8) and second one is formed below the last combination hole (3) on the proximal portion of shaft (8).