Adjustable, simultaneous tibial fixation device for cruciate ligaments

Abstract

There are many implants used in tibial fixation for tendon grafts used for cruciate ligaments reconstructions. These methods include buttons, staples, interference screws (metal & biodegradable), and hybrid fixation (e.g. screw and staples (. All ofthese methods have many disadvantages. I designed a tibial fixation device that enables direct fixation of the graft on the tibial cortex. It has the advantage of achieving a simultaneous tibial and femoral fixation of the grafts without any additional steps for tibial fixation of the graft (i.e. tibial and femoral fixations occur at the same moment); so, it saves time and effort. It allows for fine tuning of the graft tension after being fixed by a mechanism that we put to transfer rotatory motion into linear movement. It can be manufactured from biomaterials, and from materials that can induce bone formation to allow for early healing of the graft. We put in consideration that this device has to be easily applied, safe for the patient, forgiving for the tendon graft, can be used for all graft types, can be used for short grafts made from one tendon, suitable for all lengths of tibial tunnels, suitable for primary and revision.

Description

[0001] , SimultaneousTibial Fixation Device for Cruciate Ligaments.

[0002] Technical Field

[0003] Introduction:

[0004] The knee cruciate ligaments (anterior and posterior) are present inside theknee joint, and are responsible for knee stability. These ligaments are frequently torn in sports and other activities. Torn ligaments are mostly notcapable for healing due to several factors, and have to be reconstructed again. Ligament reconstruction is a widely accepted surgical procedure all over the world, and is done by using tendons as grafts (auto-grafts or allografts). Thechosen tendon is reshaped and inserted into the knee through tibial andfemoral tunnels. The femoral and tibial tunnels are done in the same anatomiclocation of the native ligaments. After graft insertion into the knee, the grafthas to be tensioned, and strongly fixed in both of the tibial and femoral tunnel. In the early stages, the graft depends entirely on the fixation methods until itheals to bone within the tunnels. Several implants are used for either femoralor tibial fixation. Success of this surgical procedure depends on many factorslike, graft size, perfect anatomic location of the tunnels, and the method of fixation. Strong fixation devices allow for early mobilization of the knee andreturn to the preinjury activity level. There are many types of implants for femoral and tibial fixation. There areseveral disadvantages of the tibial fixation devices that I tried to overcome, and put new advantages through this device. We have to put in considerationthat the quality of the proximal tibial bone is weaker and it has less mineraldensity than that of the femoral bone; so, stronger fixation is needed. Someput hybrid fixation to secure the graft in the tibial side to provide back up forthe fixation.

[0005] The scope of the device that I apply for patent here is considered for a tibialfixation device for cruciate ligament reconstruction. This device providesdirect fixation of the graft on the tibial cortex; so the graft is connected directlyto the device and to the tibial cortex. It allows for intra-tunnel fixation too. Tibial fixation occurs simultaneously with the femoral fixation (at the samemoment the graft is pulled into the knee and fixed at the femoral side, thetibial fixation will be done without any additional steps), this saves time andeffort. The graft tension can beadjusted by this device after being fixed. Itis designed to fit for all types of grafts and for all tibial tunnellengths. Itcan be used for primary and revision surgeries.

[0006] Background Art:

[0007] Old art

[0008] There are many types of implants for femoral and tibial fixation. Thereare several disadvantages of thetibial fixation devices that I tried toovercome, and put new advantages through this device. We have to put intoconsideration that the quality of the proximal tibial bone is weaker and ithas less mineral density than that of the femoral bone; so, strongerfixation is needed.

[0009] The old methods of fixation include:

[0010] 1 -Interference screws(metal or biodegradable). This method relieson compressing the graft within the tibial tunnel to the tunnel walls, as itis put side by side with the graft.

[0011] 2-Buttons

[0012] There is a connection between the graft and the button by very strongfibers. The button is fixed to the tibial cortex, while the graft is inside thetibial tunnel. It is a suspensory type of fixation called cortical fixation.

[0013] 3-Staples

[0014] The graft is fixed on the upper tibial cortex away from the outer apertureof the tibial tunnel.

[0015] 4-Hybrid fixation. By using two fixation methods from thetibial side e.g. interference screw and staples.

[0016] Disclosure of the Invention:

[0017] Summary of Invention

[0018] The scope of the device that I am applying for here is considered fora tibial fixation device for cruciate ligament reconstruction. This deviceprovidesdirect fixation of the graft on the tibial cortex; so the graft is connected directly to the device and to the tibial cortex. It allows forintra-tunnel fixation too. Tibial fixation occurs simultaneously with thefemoral fixation (at the same moment the graft is pulled into the knee and fixed at the femoral side, the tibial fixation will be done without anyadditional steps), this saves time and effort. The graft tension can beadjusted by this device after being fixed. It is designed to fit for alltypes of grafts and for all tibial tunnellengths. It can be used forprimary and revision surgeries.

[0019] Technical Problem problems with the old art:

[0020] For the interference screws

[0021] 1 -Needs long graft. Longer grafts are available; however, affording a longgraft can be on the expense of the graft diameter with higher risks offailure. To solve the problem and affording a suitable graft length with a suitable size, two tendons instead of one have to be harvested. Harvesting two tendons has more morbidity on the patient.

[0022] 2-Since it depends on compressing the graft within the tunnel againstbone; so, it is a weak fixation device as the bone quality in this region isweak, and needs back up fixation with more cost and complications.

[0023] 3-Delays graft healing within the tunnel, as the screw is interposedbetween the graft and bone. 4-As it is put within the tunnel parallel to the graft; so, this may lead tograft slippage if the graft is tensioned from the femoral side.

[0024] 5-If we use internal splint beside the graft, we have to use an additionalfixation device beside the screw, with more cost and effort.

[0025] 6-Tunnel dilatation is frequently encountered with screw fixation. Dilatedtunnels represent a problem in revision surgery, as we need to stage theoperation into two stages, with the first stage for filling the tunnel withbone graft; while, the reconstruction surgery is done in the second stage.

[0026] 7-Screws are not suitable fixation devices in revision surgery, because thetunnels are mostly dilated with very large diameter. There is no screwwith a large diameter that can fill the dilated tunnels.

[0027] 8-Cannot afford graft tension adjustment. Screws are only fixationdevices without the ability of performing tension through it.

[0028] 9-Screw slippage outside the tibial tunnel is frequently encountered. Thisleads to loss of fixation and prominence.

[0029] For buttons

[0030] 1 -It is a suspensory method of fixation. There is a connection of verystrong fibres between the graft and the button with high potential of graftcollagen fraying and tearing over these fibres.

[0031] 2-Tunnel dilatation (as in screws) is well encountered with buttons.

[0032] Button fixation devices are associated with large degree of graft motion within the tunnel.

[0033] 3-Sometimes, the fibres connecting the button with the graft are tomwhile pulling the graft into the knee joint. This complication will besolved by changing the button with another one with more cost and timeloss, with higher potential for complications.

[0034] For staples

[0035] 1 -Frequently broken on application.

[0036] 2-Prominent under the skin, so may need removal with another surgicalprocedures.

[0037] 3-Fixation is away from the joint allowing for more graft motion withinthe tunnel and tunnel dilatation.

[0038] Solution to Problem

[0039] It is a tibial fixation devicefor grafts used in cruciate ligamentsreconstruction. - It gives a direct cortical fixation for the graft, as thegraft is directly connected to the device without any suture connectionthat may fray or tear the graft (direct fixation is stronger than indirect fixation). -The site of graft connection to the device is smooth, so it is safe andforgiving.

[0040] - It allows using short graft. This means we can harvest one tendoninstead of two from the patient with less morbidity for the patient.lt provides a simultaneous femoral and tibial fixation, without anyadditional steps, so it saves time and effort.

[0041] -It can control graft tension (i.e. it is adjustable. This is available becauseof a mechanism that transforms the rotatory motion into a linear motionwith subsequent control of the graft tension and without any effect on thefixation.

[0042] -It can be manufactured from biomaterials that can induce bone formationwith faster healing of the graft within the tunnel. This is similar to Bone-Tendon- Bone grafts; however, without facing the morbidity of takingBone- Tendon- Bone grafts from the patient. This also, avoids theproblem of tunnel dilatation.

[0043] Putting in consideration that this device is:

[0044] Applicable, manufacturable, safe on the patient and the graft, completely sterile, suitable for all graft types and all tibial tunnel lengths, andsuitable for primary and revision surgery.

[0045] The device parts are:

[0046] 1-A central threaded screw of about 5mm diameter. One end of the screw hasan open part about 8mmx8mm for connection to the graft [can be hockshaped], the edges of this opening are smooth so safe on the graft collagen. The other end of the screw has an opening for insertion of a special handle.

[0047] 2-A locking nut. It is cylindrical in shape and has threads on the inner surface, so can be applied over the body of the outer nut to lock over the cortical plate.

[0048] 3-A cortical plate. It is the part of the device that fixes the whole device on thecortex of the upper tibial surface. Its longest diameter is about 20-30mm, so itis larger than any tibial tunnel diameter allowing for being compressed on thetunnel aperture. It has 2 circular extensions, one on each side, to increasethe diameter of the plate, and can help for internal splint fixation (if used withthe graft) without the need for any additional fixation devices. It has one facethat is compressed on the cortex, and an outer face that holds the head ofthe outer nut. When the device is fixed and the cortical plate is compressedagainst the cortex, rotation of the outer nut head by the special driver willresult in linear motion of the screw with control on the degree of graft tension.

[0049] 4-Outer nut. It has a body and a head. The body is inserted into the central opening of the cortical plate, as its diameter is less than that of the opening. The external surface of the body is threaded for the application of the lockingnut. The whole outer nut is Cannulated allowing for insertion of the centralthreaded screw in it.

[0050] 5 -Special nut driver.

[0051] 6-Special handle. Advantageous Effects of Invention

[0052] The scope of the device that I apply for patent here is considered for atibialfixation device for cruciate ligament reconstruction. This deviceprovides direct fixation of the graft on the tibial cortex; so the graft isconnected directly to the device and to the tibial cortex. It allows forintra-tunnel fixation too. Tibial fixation occurs simultaneously with thefemoral fixationfat the same moment the graft is pulled into the knee andfixed at the femoral side, the tibial fixation will be done without anyadditional steps), this saves time and effort. The graft tension can beadiusted by this device after being fixed. It is designed to fit for all types of grafts and for all tibial tunnellengths. It can be used for primaryand revision surgeries.

[0053] Putting in consideration that the device is:

[0054] Applicable, safe for the graft and the patient, manufacturable, completely sterile, suitable for all types of grafts and tibial tunnel lengths, andsuitable for primary and revision surgery.

[0055] Brief Description of Drawings

[0056] The device is demonstrated by 17 drawings, including 36 figures thatclarify the different parts of the device both separated and assembled.

[0057] Steps of the device function are also demonstrated. Mechanism of grafttensioning after being fixed is also clarified. Dimensions andmeasurements of the different parts were put to be compatible with eachothers; however, the manufacturer can change and adjust thesesdimensions for being manufacturable without any contradiction to themain idea. Shapes and dimensions are liable for modification providedthat the main idea, significance, and function are achieved.

[0058] Fig.l

[0059] [Fig.l] Drawing No Cl ): Represents the different parts of the device(separated)- seen from above

[0060] Figure No (1): Represents 3D of the different parts of the device (separated), and it shows:

[0061] Part 1 : Represents the central threaded screw.

[0062] Part 2: Represents the locking nut.

[0063] Part 3: Represents the cortical plate.

[0064] Part 4: Represents the outer nut.

[0065] Part 5: Represents the special screw driver.

[0066] Part 6: Represents the handle.

[0067] Figure No (2): Represents diagram of the different parts of the device (separated), and it shows:

[0068] Part 1 : Represents the central threaded screw.

[0069] Part 2: Represents the locking nut.

[0070] Part 3: Represents the cortical plate.

[0071] Part 4: Represents the outer nut.

[0072] Part 5: Represents the special screw driver.

[0073] Part 6: Represents the handle.

[0074] Drawing No (2) Represents the different parts of the device (assembled)- seen from above.

[0075] Figure No (3): Represents 3D of the different parts of the device (assembled), and it shows:

[0076] Part 1 : Represents the central threaded screw.

[0077] Part 2: Represents the locking nut.

[0078] Part 3: Represents the cortical plate.

[0079] Part 4: Represents the outer nut.

[0080] Part 5: Represents the special screw driver.

[0081] Part 6: Represents the handle.

[0082] Figure No (4): Represents diagram of the different parts of the device (assembled), and it shows:

[0083] Part 1 : Represents the central threaded screw.

[0084] Part 2: Represents the locking nut.

[0085] Part 3: Represents the cortical plate.

[0086] Part 4: Represents the outer nut.

[0087] Part 5: Represents the special screw driver.

[0088] Part 6: Represents the handle.

[0089] Drawing No (3):Represents the different parts of the device (separated)- seen from the side

[0090] Figure No (5): Represents 3D of the different parts of the device (separated), and it shows:

[0091] Part 1 : Represents the central threaded screw.

[0092] Part 2: Represents the locking nut.

[0093] Part 3: Represents the cortical plate.

[0094] Part 4: Represents the outer nut.

[0095] Part 5: Represents the special screw driver.

[0096] Part 6: Represents the handle.

[0097] Figure No (6): Represents diagram of the different parts of the device (separated), and it shows:

[0098] Part 1 : Represents the central threaded screw.

[0099] Part 2: Represents the locking nut.

[0100] Part 3: Represents the cortical plate.

[0101] Part 4: Represents the outer nut.

[0102] Part 5: Represents the special screw driver.

[0103] Part 6: Represents the handle.

[0104] Drawing No (4) Represents the different parts of the device (assembled)- seen from the side.

[0105] Figure No (7): Represents 3D of the different parts of the device (assembled), and it shows:

[0106] Part 1 : Represents the central threaded screw.

[0107] Part 2: Represents the locking nut.

[0108] Part 3: Represents the cortical plate.

[0109] Part 4: Represents the outer nut.

[0110] Part 5: Represents the special screw driver.

[0111] Part 6: Represents the handle.

[0112] Figure No (8): Represents diagram of the different parts of the device (assembled), and it shows:

[0113] Part 1 : Represents the central threaded screw. Part 2: Represents the locking nut.

[0114] Part 3: Represents the cortical plate.

[0115] Part 4: Represents the outer nut.

[0116] Part 5: Represents the special screw driver.

[0117] Part 6: Represents the handle.

[0118] Drawing No (5) Represents the central threaded screw.

[0119] Figure No (9): Represents 3D of thecentral threaded screw, and it shows:

[0120] Part 1 : Represents the open end of the screw for graft attachment.

[0121] Part 2: Represents the threaded shaft of the screw.

[0122] Part 3 : Represents the other end of the screw with an opening for handle insertion.

[0123] Figure No (10): Represents a diagram with the dimensions of thecentralthreaded screw, seen from above, and it shows:

[0124] Part 1 : Represents the open end of the screw for graft attachment.

[0125] Part 2: Represents the threaded shaft of the screw.

[0126] Part 3 : Represents the other end of the screw with an opening for handleinsertion.

[0127] Drawing No (6) Represents the central threaded screw, seen from the sideand end.

[0128] Figure No (11): Represents a diagram with the dimensions of thecentral threaded screw, seen from the side, and it shows:

[0129] Part 1 : Represents the open end of the screw for graft attachment.

[0130] Part 2: Represents the threaded shaft of the screw.

[0131] Part 3 : Represents the other end of the screw with an opening for handleinsertion.

[0132] Figure No (12): Represents a diagram of thecentral threaded screw, seenfrom the end.

[0133] Drawing No (7) Represents the locking nut.

[0134] Figure No (13): Represents 3D of the locking nut, and it shows:

[0135] Part 1 : Represents the outer smooth surface of the nut.

[0136] Part 2: Represents the inner threaded surface of the nut. Figure No (14): Represents a diagram of the locking nut, seen from front, showing the dimensions, and it shows:

[0137] Part 1 : Represents the outer smooth surface of the nut.

[0138] Part 2: Represents the inner threaded surface of the nut.

[0139] Drawing No (8) Represents the locking nut.

[0140] Figure No (15): Represents a diagram of the locking nut, seen from the side, showing the dimensions, and it shows:

[0141] Part 1 : Represents the outer smooth surface of the nut.

[0142] Part 2: Represents the inner threaded surface of the nut.

[0143] Figure No (16): Represents a diagram of the locking nut, seen from the side, showing the dimensions, and it shows:

[0144] Part 1 : Represents the outer smooth surface of the nut.

[0145] Part 2: Represents the inner threaded surface of the nut.

[0146] Drawing No (9) Represents the cortical plate.

[0147] Figure No (17): Represents 3D of the cortical plate, and it shows:

[0148] Part 1 : Represents the outer surface of the circular part of the plate.

[0149] Parts 2&3 : Represent the two side circular extensions with central holes.

[0150] Part 4: Represents the side of the cortical plate for the head of the outer nut.

[0151] Part 5 Represents the central opening of the plate.

[0152] Figure No (18): Represents a diagram of the cortical plate, front view with the dimensions, and it shows:

[0153] Part 1 : Represents the outer surface of the circular part of the plate .

[0154] Parts 2&3 : Represent the two side circular extensions with central holes.

[0155] Part 4: Represents the side of the cortical plate for the head of the outer nut.

[0156] Part 5 Represents the central opening of the plate.

[0157] Drawing No (10) Represents the cortical plate.

[0158] Figures 19 &20 represent side views of the plate with the dimensions.

[0159] Drawing No (11) Represents the outer nut. Figure No (21): Represents 3D of the outer nut, and it shows:

[0160] Part 1 : Represents the head of the outer nut.

[0161] Parts 2:Represents the body of the outer nut with its threaded outer surface.

[0162] Part 3 : Represent the inner threaded surface of the nut.

[0163] Figure No (22): Represents a diagram of the outer nut with the dimensions, seen from the side, and it shows:

[0164] Part 1 : Represents the head of the outer nut.

[0165] Parts 2:Represents the body of the outer nut with its threaded outer surface.

[0166] Drawing No (12) Represents the outer nut.

[0167] Figure No (23): Represents a diagram of the outer nut with the dimensions, seen from the side, and it shows:

[0168] Part 1 : Represents the head of the outer nut.

[0169] Parts 2:Represents the body of the outer nut with its threaded outer surface.

[0170] Figure No (24): Represents a diagram of the outer nut with the dimensions, seen from the front of the head.

[0171] Drawing No (13):Represents the special nut driver.

[0172] Figure No (25): Represents 3D of the special nut driver, and it shows:

[0173] Part 1 : Represents the handle of the special nut driver.

[0174] Parts 2 Represents the outer surface of the body of the special nut driver.

[0175] Part 3 : Represent the inner surface of the head of the special nut driver.

[0176] Figure No (26): Represents a diagram of the special nut driver with thedimensions, seen from the side.

[0177] Drawing No (14) Represents the special nut driver.

[0178] Figure No (27): Represents a diagram of the special nut driver with thedimensions, seen from the front.

[0179] Figure No (28): Represents a diagram of the special nut driver with thedimensions, seen from another side view.

[0180] Drawing No (15) Represents the handle.

[0181] Figure No (29): Represents 3D of the handle.

[0182] Figures 30, 31&32 represent side views of the handle with the dimensions.

[0183] Drawing No (16) Represents the graft after being fixed in the femur and tibia, (in a slack state).

[0184] Figure No (33): Represents 3D of the graft after being fixed in the femur andtibia, (in a slack state).

[0185] Part 1 : Represents the site of graft fixation at the femur.

[0186] Part 2: Represents a curved arrow that demonstrates the slack state of th egraft.

[0187] Part 3 : Represents the slack graft.

[0188] Part 4: Represents the part of the screw at which the graft is attached.

[0189] Part 5: Represents the cortical plate fixed and compressed at the tibial cortex.

[0190] Part 6: Represents an arrow that demonstrates the direction of rotating the head of the outer nut by the special nut driver (clockwise) for graft tensioning.

[0191] Part 7: Represents the handle of the special nut driver.

[0192] Part 8: Represents an arrow that shows the direction of the outward linearm oti on of the central screw taking with it the graft, and resulting in grafttensioning.

[0193] Part 9: Represents the handle that prevents rotation of the whole device, itallows rotation to occur only at the head of the outer nut.

[0194] Part 10: Represents drawing of the outlines of the tibial tunnel. The tibialfixation device with the graft attached to it lies inside the tunnel, with thecortical plate fixed on the surface of the tunnel.

[0195] Figure No (34): Represents a diagram of the graft after being fixed in thefemur and tibia, (in a slack state).

[0196] Part 1 : Represents the site of graft fixation at the femur.

[0197] Part 2: Represents a curved arrow that demonstrates the slack state of th egraft.

[0198] Part 3 : Represents the slack graft.

[0199] Part 4: Represents the part of the screw at which the graft is attached.

[0200] Part 5: Represents the cortical plate fixed and compressed at the tibial cortex.

[0201] Part 6: Represents an arrow that demonstrates the direction of rotating thehead of the outer nut by the special nut driver (clockwise) for graft tensioning.

[0202] Part 7: Represents the handle of the special nut driver.

[0203] Part 8: Represents an arrow that shows the direction of the outward linearm oti on of the central screw taking with it the graft, and resulting in grafttensioning.

[0204] Drawing No (17) Represents the graft after being fixed in the femur and tibia, (in a tensioned state).

[0205] Figure No (34): Represents 3D of the graft after being fixed in the femur andtibia, (in a tensioned state). Part 1 : Represents the site of graft fixation at the femur.

[0206] Part 2: Represents the tensioned graft.

[0207] Part 3 : Represents a straight arrow that demonstrates the tensioned state ofthe graft.

[0208] Part 4: Represents the part of the screw at which the graft is attached.

[0209] Part 5: Represents the cortical plate fixed and compressed at the tibial cortex.

[0210] Part 6: Represents the handle of the special nut driver after being rotatedclockwise.

[0211] Figure No (35): Represents a diagram of the graft after being fixed in thefemur and tibia, (in a tensioned state).

[0212] Part 1 : Represents the site of graft fixation at the femur.

[0213] Part 2: Represents the tensioned graft.

[0214] Part 3 : Represents a straight arrow that demonstrates the tensioned state ofthe graft.

[0215] Part 4: Represents the part of the screw at which the graft is attached.

[0216] Part 5: Represents the cortical plate fixed and compressed at the tibial cortex.

[0217] Part 6: Represents the handle of the special nut driver after being rotatedclockwise.

[0218] Description of Embodiments

[0219] This tibial fixation device is designed to allow for a simultaneoustibial and femoral fixation; this occurs when, the graft is pulledinto the knee joint until the femoral side of the graft getsinto the knee joint and then into the femoral tunnel, and finally outside thefemoral tunnel. Now the graft is ready for the femoral fixation (with a button orscrew), at this time the cortical plate of our device will be reached andcompressed on the tibial cortex achieving the tibial fixation without anyadditional steps for the tibial fixation.

[0220] I have a mechanism that can transfer the rotatory motion into a linear motion soas to adjust the graft tension after being fixed in the femur and tibia. When the different parts of the device are put together, they form one unit.

[0221] Parts of the device:

[0222] Part 1, drawings (1, 2, 3 &4) represents the central threaded screw with adiameter of about 5mm. Part 1, drawings (5&6) represents the end of thescrew that has an opening for graft attachment.Part 2, drawings (5&6)represents the threaded portion of the screw. Part 3, drawings (5&6)represents the other end of the screw; it has an opening for the handle. Part 2, drawings (1, 2, 3 &4)represents the locking nut, it is Cannulatedwith threads on the inner surface (part 2 drawing 7), the outer surface issmooth (part 1 drawing 7). It acts with the outer nut to lock the cortical plate atthe required length from the screw.

[0223] Part 3, drawings (1, 2, 3 &4) represents the cortical plate. It is the part ofthe device that fixes the whole device on the cortex of the upper tibial surface. Its longest diameter is about 20-30mm, so it is larger than any tibial tunneldiameter allowing for being compressed on the tunnel aperture. It has 2circular extensions, one on each side, to increase the diameter of the plate, and can help for internal splint fixation (if used with the graft) without the needfor any additional fixation devices. It has one face that is compressed on thecortex, and an outer face that holds the head of the outer nut. When thedevice is fixed and the cortical plate is compressed against the cortex, rotation of the outer nut head by the special driver will result in linear motion of the screw with control on the degree of graft tension. It is shownin (drawings 9&lo) with part 1 shows the circular part of the plate, parts 2&3show the two circular extensions, part 4 shows the outer place for the head ofthe outer nut, and part 5 shows the central circular opening.

[0224] Part 4, drawings (1, 2, 3 &4) represents the outer nut. It has a body and ahead. The body is inserted into the central opening of the cortical plate, as itsdiameter is less than that of the opening. The external surface of the body isthreaded for the application of the locking nut. The whole outer nut is cannulated allowing for insertion of the central threaded screw in it. It isshown in (drawings 11&12) with part 1 show the head, part 2 shows the body, and part 3 shows the inner threaded part.Part 5, drawings (1, 2, 3 &4) represents the special nut driver. Its parts areshown in (drawings 13&14), with part 1 show the handle of the driver, part 2 shows the head, and part 3 shows inner part of the head, .Part 6, drawings (1, 2, 3 &4) represents the special handle. It is shown in(drawingl5).

[0225] How the device works

[0226] 1 -Assembly of the parts

[0227] The locking nut is introduced first into the threaded screw from the end of thescrew that has the handle opening. Then the outer nut is introduced into thecentral circular part of the cortical plate, and rotated clockwise over the screwuntil reaching the desired distance. The locking nut is rotated clockwise over the threaded part of the body of the nut to get the cortical plate locketbetween it and the head of the outer nut.(Drawings 1&3) show the separated different parts of the device. (Drawings 2&4) show the assembled different parts of the device.

[0228] 2- Putting the graft in the other end of the central threaded screw where thereis an opening for it with smooth edges (part 1 in drawings 5 &6). The otherend of the graft is attached with the femoral fixation device (if a button is usedfor femoral fixation) or to sutures (if a screw is used for femoral fixation). 3 -Passage of the graft into the tibial tunnel, then the knee joint, then thef emoral tunnel until the graft (or the femoral fixation device) is outside thefemoral tunnel where it is fixed. At this moment the cortical plate will beconcurrently compressed and fixed against the tibial cortex without anyadditional steps for tibial fixation i.e. (Simultaneous fixation).

[0229] 4-Mechanism Graft tension adjustment. After graft fixation in the tibia andfemur, graft tension adjustment can be performed by rotating the head of theouter nut by the special screw driver; since the head of the outer nut abutsthe cortical plate against the tibial bone cortex, so, rotation of the head willresult in outward linear motion of the screw rather than forward progress ofthe nut. Outward linear motion of the screw will pull the graft outward resultingin graft tension, as the graft is fixed at the femur. The handle will prevent rotation of the whole device during rotation of the outer nut driver.

[0230] Drawing 16 shows the graft fixed at the femur and tibia. The graft is in a laxcondition.

[0231] Drawing 17 shows the graft fixed at the femur and tibia. The graft is in atensioned condition.

Claims

ClaimsClaim 1 : Tibial cortical fixation device that issuitable for all types of grafts used for cruciate ligament reconstruction. It allows for direct fixation of the graft on the tibiawithout any connecting fibres between the graft and the device. Itallows for both cortical and intra-tunnel fixation. It allows forsimultaneous femoral and tibial fixation, it is adjustable, and can bemade from materials that induce bone formation and early rafthealing. This device is composed of - entral threaded screw ocking nut ortical plate uter nut pecial screw driver andle laim 2: The device as in claim 1, claim 2 includes the entral threaded screw.lt has a threaded shaft with a diameter ofabout 5mm. It has one end at which the graft s attached through anopening of about SmmxSmm withrounded edges. The other parts ofthe device will be ttached at the threaded shaft at a predetermineddi stance of the shaft. The other end of the screw is for the andleattachment. laim 3: The device as in claim 1, claim 3 includes thelocking nut that is used to lock all parts of the device ver thethreaded screw at a predetermined distance of the screw. It is screwedclockwise over the outer part f the body of the outer nut; so, it locksover the cortical plate. laim 4: The device as in claim 1, claim 4 includes thecortical plate. It is the part of the device that will be ompressed overthe outer surface of the upper tibia at the tibial tunnel aperture. It iscircular with a central ircular opening with a diameter larger thanany tibial tunnel diameter. It has two circular extensions, one on achside, to increase the plate diameter, and also, to allow for independentfixation of the artificial internal plint (if used). It has one face thatwill be compressed on the tibial cortex, and an outer face that has a ircular place for the head of the outer nut. Clockwise rotation of theouter nut against the plate (which is ixed and compressed on thetibial cortex) will result in a linear motion of the screw in an outwarddirection, ith subsequent tensioning of the graft inside the joint.Claim 5: The device as in claim 1, claim 5 includestheouter nut has a head and a body. The head shape is to fit with aspecial screwdriver. The outer nut is cannulated to allow for insertionof the central screw. The diameter of the body of the outer nut is lessthan that of the central opening of the cortical plate so it can be introduced into it. The body outer surface is threaded for applicationof the locking nut over it, so locking the cortical plate. Clockwiserotation of the head by the driver will transfer the rotatory motion intoan outward linear motion of the central screw with subsequent tensioning of the graft.Claim 6: The device as in claim 1, claim 6 includesaspecial nutdriver to rotate the head of the outer nut which abuts over thecortical plate that abuts over the tibial cortex) in a clockwisedirection, resulting in utward linear motion of the central screw withsub sequent tensioning of the graft. laim 7: The device as in claim 1, claim 7 includesthe handle can beinserted into a special opening in the nd of the central screw. It helpsto control and prevent rotation of the whole device with the graftfixed overt when the driver is rotated over the head of the outer nut.

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