Surgical Technique Primary Treatment Tibial Cut First ASIA

Transcription

1 Surgical Technique Primary Treatment Tibial Cut First ASIA

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3 Table of Contents Chapter Page Design features 1 ACS system overview 2 Surgical approach 3 Tibial alignment 3 Tibial resection 6 Femoral sizing 7 Anterior and posterior resection 8 Distal resection 10 Femoral chamfer resection 11 Final tibial preparation 12 Trial reduction 14 Final femoral preparation 16 Implantation of the components 17 Patella preparation 18 ACS Implants 19 ACS Instrument Trays 20 Design Features Total knee arthroplasty has evolved into a major tool in the treatment of severe arthritis. Implantation of an artificial joint may lead to either disappearance or considerable reduction of pain and will improve function and quality of life for the patient. A total knee implant with a proven design, minimal wear characteristics and an optimal mobility may provide the best solution. The ACS knee was designed to minimize the problems of wear of the polyethylene within the implant in order to provide maximum longevity of the implant. Cobalt Chromium alloy, with its optimal wear characteristics and mechanical properties is the material of choice for the femoral and tibial component. Adding a Titanium Nitride ceramic coating contributes to further reducing the wear of the polyethylene component and at the same time, in the case of cementless application, providing a better surface for bony ingrowth. Wear of polyethylene has been acknowledged as the major cause for implant failure [2,3,4,5]. Wear tests performed at the University of Munich (Prof. Dr H.J. Refior and Dipl. Ing. J. Huber) [1], and at the IMA Dresden [6] have shown superior wear characteristics when Cobalt Chromium alloy is combined with a ceramic Titanium Nitride coating. The design of the ACS has proven its advantages in terms of wear characteristics compared to a non-ceramic coated implant. The optimal femoral-tibial congruency provided by the ACS protects the polyethylene from wear and damage during millions of cycles. Furthermore, the contact stress is reduced by perfectly matching articulating radii in three planes, distributing the loads over a large area Note: The described surgical technique is the suggested treatment for the uncomplicated procedure. In the final analysis the preferred treatment is that which addresses the needs of the individual patient. Copyright Information: Copyright: Cepthar, ACCIS, ACS, DiaLoc, EcoFit, BethaLoc, Load Shift, implavit, implatan and implacross are registered trademarks of implantcast GmbH. The use and copy of the content of this brochure are only allowed with prior written permitssion of implantcast GmbH. 1

4 ACS System Overview Tibial Component Tibial Inserts* Femoral Component Patella Component 26 mm 29 mm 32 mm Size 1-5 Size 1-5 Size 1-5 Size 1 Size 2 Size 2,5 Size 3 Size 4 Size 5 Size 1 Size 2 Size 3 Size 4 Size 5 Size 2-7 Size 2-7 Size 3-7 Size 3,5-7 Size 5-7 Size 2 Size 3 Size 3,5 Size 4 Size 5 Size 6 Size 7 * All tibial inserts are available in thiecknesses of 10.0 mm, 12.5 mm, 15.0 mm and 17.5 mm* 2

5 Surgical Approach and Tibial Alignment With the knee slightly flexed a straight mid-line incision is made over the patella, through the retinaculum, capsule and synovium. Alternatively in case of neutral of varus deformity a medial parapatellar, or in case of a valgus deformity a lateral parapatellar incision can be selected. The knee is flexed to 90. The tibial cutting block with a 5, 7 or 10 posterior slope is selected and mounted on the tibial cutting guide. The long-spike of the alignment tower is introduced into the proximal tibial spine. 3

6 Tibial Alignment The ankle clamp is placed around the ankle and locked with the knurled knob. The malleolar wings are positioned parallel to the transmalleolar axis to establish rotational alignment. Place the tibial cutting block on the tibial cutting guide and connect this to the ankle clamp The rod (1) is placed parallel to the intramedullary axis of the tibia. The posterior slope of the tibia should be parallel to the selected resection block. The ankle clamp knob (2) is locked and the second spike (3) of the alignment guide is inserted. The alignment tower(4) can now be locked. The stylus (5) is attached to the tibial cutting block and lowered till the tip (6) of the stylus reaches the deepest point of the most affected part of the tibial plateau by turning the adjustment cylinder (7). The 2 mm tip is used. In case of a major medial defect the 10 mm tip can be used to determine the level of resection on the lateral part of the tibial plateau. 4

7 Tibial Alignment The stylus is now removed. If at a later stage the level of resection is too high the cutting block can be re-positioned over these fixation pins accurately in a lower position. All resection blocks have multiple holes for the fixation pins, which allows to move the blocks in proximal and distal direction with 2.5 mm increments. The spring (2) is disconnected from the ankle clamp and the telescoping part of the alignment tower is unlocked. The alignment tower is removed using the sliding hammer. 5

8 Tibial Resection The cutting block is placed flush onto the tibia and the alignment is checked with the alignment rod. The distal end of the rod should be in line with the second toe and just lateral to the anterior tibial tendon. In case of unsatisfactory alignment a special 2 valgus/varus recutting block can be used for correction. The standard tibial cutting block is replaced by the varus/valgus correction block by sliding it over the pins using the same holes. The tibial cutting block is fixed onto the tibia using two predrilled fixation pins. Once the level of resection has been determined additional oblique pins may be inserted. The saw capture is placed and the resection level is checked with the resection check. The soft tissues are protected and the distal tibia is resected using an ACS saw blade. 6

9 Femoral Sizing The size of the femoral implant is determined by measuring the lateral condyle with the femoral sizing template. The outside/inside of the template corresponds with the outer/inner surface of the femoral component. The interior flange of the femoral component should be held in the same plane as the anterior cortex. The alignment stylus is attached to the femoral resection block of the corresponding size. The stylus is slid beneath the quadriceps muscle anteriorly onto the periosteum of the femur. The yoke should be flush and parallel to the longitudinal axis of the femur. The A/P femoral resection block is centered between the epicondyles and fixed with a pin. The position of the femoral guide hole is in general 3-5 mm medial of the intercondylar notch. The central hole is drilled with the 9 mm starter drill. The drill is removed and the intramedullary guide rod is inserted using the quick lock T-handle. The stylus can now be removed. The A/P resection block should be allowed to rotate freely. 7

10 Anterior and Posterior Femoral Resection The femoral block positioner is placed in the slot of the resection block and the knee is flexed so that the positioner rests flat on the previously resected proximal tibia. If the stability is not satisfactory the appropriate tibial spacer shim is placed under the femoral guide positioner and the size recorded. The saw capture is attached to the tibial resection block The level of resection can be checked using the resection check. The anterior resection should be flush with the anterior cortex of the femur. The femoral resection block is pinned in the middle predrilled holes when the collateral ligaments are tensioned (balanced). The saw capture is attached and the anterior femoral resection performed. The slot accommodates the ACS sawblades. 8

11 Anterior and Posterior Femoral Resection The saw capture is attached to the femoral resection block and the anterior femoral condyle is resected. The saw capture is removed and repositioned on the posterior side and the femoral condyle is resected. The spacer block adapter is attached on the spacer block and the spacer block is inserted into the flexion gap. This represents the thickness of a 10 mm bearing component. Adapters (12.5, 15.0, 17.5 and 20.0 mm) can be added to increase the tension on the collateral ligaments. The external alignment rod is placed through the spacer block handle to check the frontal and lateral plane alignment on the tibia. 9

12 Distal Resection The required valgus angle is selected and the distal femoral cutting block is placed on the femoral alignment guide in such a way that the block corresponds with the mark on the medial side of the alignment guide. 3, 4, 5 and 6 cutting blocks and a 2 recutting block are available. The distal femoral cutting block should lie flush with the anterior resection plane and it is attached to the bone using two predrillled pins. With the alignment host and the external rod, attached to the distal femoral cutting block, it is checked that the rod is centered on the femoral head (two finger widths medial to the anterior superior iliac spine). The valgus angle can be adjusted 2 using the varus/valgus recutting block. 10

13 Distal Resection and Femoral Chamfer Resection The alignment host and rod and the femoral resection block are removed. The spacer block is placed parallel to the tibial resection. The distal femoral cut is made approximately 2 mm proximal of the intercondylar notch. The extension gap is checked and additional adapters can be added to tension the collateral ligaments. The saw capture is mounted and the distal femoral condyles are resected. The distal femoral cutting block is removed and the femoral chamfer block of the appropriate size is placed on the resected femur. Care should be taken that this chamfer block lies flush with the resected femur. The femoral chamfer block is attached to the bone using two pins. The posterior and anterior chamfer cuts are performed through the slots. 11

14 Final Tibial Preparation The tibial trial tray is placed on the surface of the resected tibia and the correct rotational position of the tibial component is checked. Two 3.2 mm drill holes are made and the pins with stop are inserted. The pins are left in position. The tibial reamer guide of the correct size is placed on the tibial trial tray. The reamer guide should be fully inserted into the recession in the tibial trial tray. The reamer is used to prepare the bone for the tibia. In case of softer bone the cancellous bone may be impacted using the tibial punch. The correct depth is reached when the flange of the reamer meets the top of the reamer guide. 12

15 Final Tibial Preparation In case the stem extension will be implanted a bushing is placed inside the tibial reamer guide and the tibial stem drill is used. Pre-drilling the tibia is done till the first marker on the reamer. The second and third markings are intended for the use of longer stem extensions. The fin punch of the correct size is introduced through the tibial trial tray to prepare the bone for the finned tibia component. The fin punch should be advanced fully until it lies flush with the top of the tibial trial tray. 13

16 Trial Reduction The centralizer of the corresponding size is placed in the tibial trial tray. The centralizer should lie flush with the surface of the trial tray. The tibial trial of the size corresponding with the femoral component selected is inserted first.the appropriate thickness bearing was defined previously by the spacer block but can be adjusted by using the trial adapters. 14

17 Trial Reduction The femoral trial is attached to the coupled impactor and the trial component is seated. The stability both in flexion and in extension is checked and the range of motion is established. 15

18 Final Femoral Preparation If insufficient stability is appearing with the trial inserts 10 and 12.5 mm an additional trial adapter (15, or 17.5mm) will be placed under the 10.0 mm trial insert. This will indicate that a thicker bearing should be implanted. The two holes for the fixation stems of the femoral component are drilled. A recessing cut is made from the proximal end of the femoral trial and the patellar groove is prepared with the osteotome and an oscillating saw. The tibial fixation pins and all trial components are now removed. 16

19 Implantation of the Components The tibial component is inserted first and seated with impactor. The tibial insert of the corresponding size (size of the femoral component) and of the selected thickness is inserted next. The femoral component is inserted next with the coupled impactor. In case of cemented application the non-coupled impactor can be used during the setting of the cement. 17

20 Patella preparation With the patella resection guide, the patella is resected parallel to and at the level of the quadriceps tendon attachment. Usually 9 mm will be resected from the patella dome. A remnant of at least 10 mm thickness is suggested. The bone is resected through the slot. This slot accepts the ACS saw blade. The patella drill guide is placed on the resected patellar bone and the size is measured. This size will fit any size femoral component. The patella drill with stop is used to prepare the three peg holes. For a trial redcution a patella trial can be inserted. The patella implant of the appropriate size is cemented in place and held in place during the hardening of the cement using the patella clamp. Remark:The surgical technique for a rotating patella is not described here, but is available upon request 18

21 ACS Implantats Implants ACS PE Patella Implant UHMW-PE acc. to DIN ISO 5834/1+2 Size REF 26mm mm mm ACS Femoral Component cemented implavit, CoCrMo casting alloy acc. to DIN ISO 5832/4 with TiN-coating Size Left Right , ACS Tibial Insert UHMW-PE acc. to DIN ISO 5834/1+2 Implant height Size 10.0 mm 12.5 mm 15.0 mm 17.5 mm ACS Tibial Component cemented implavit, CoCrMo casting alloy acc. to DIN ISO 5832/4 with TiN-coating Size Left & Right ,

22 ACS Instrument container upper tray REF Instruments Tibial cutting guide asia Ankle clamp asia Tibial cutting block 7 GIS Tibial cutting block 5 GIS Tibial 2 varus/valgus cutting block GIS Tibial resection stylus 2/10mm GIS Tibial cutting block 10 GIS ACS drill 126 x 3,2 mm Aaw capture 1,5 mm; size 1-5 GIS Tibial external alignment host GIS ACS pin inserter ACS pin extractor ACS fixation pin 3,2 x 97 mm External alignment rod asia ACS Instrument container lower tray REF Instruments ACS tibial handle ACS tibial reamer ACS tibial punch ACS fixation pin 3,2 x 77 mm Tibial drill bushing size 2/ Tibial drill bushing size 4/ Tibial drill bushing size 6/ Tibial trial cone size 2/ Tibial trial cone size 4/ Tibial trial cone size 6/ Handle ACS tibial fin punch size ACS tibial fin punch size ACS handle short for tibial fin punch Tibial trial tray slotted size Tibial trial tray slotted size Tibial trial tray slotted size 3, Tibial trial tray slotted size Tibial trial tray slotted size Tibial trial tray slotted size Tibial trial tray slotted size Handle for tibial drill bushing Pin 50 mm with Stop ACS resection check 20

23 ACS Instrument container upper tray REF Instruments Femoral impactor short Osteotom for patellar groove size Tibial impactor short Femoral / tibial extractor Femoral impactor guide size 1-5 ACS Instrument container lower tray REF Instruments ACS tibial trial keel ACS Patella femoral groove trial ACS patella femoral groove trial ACS Patella femoral groove trial 2, ACS patella femoral groove trial ACS patella femoral groove trial ACS femoral trial 1 left ACS femoral trial 2 left ACS femoral trial 2,5 left ACS femoral trial 3 left ACS femoral trial 4 left ACS femoral trial 1 right ACS femoral trial 2 right ACS femoral trial 2,5 right ACS femoral trial 3 right ACS femoral trial 4 right Tibial trial adapter 15 mm Tibial trial adapter 17,5 mm Tibial trial adapter 20 mm Tibial trial insert 1 10 mm Tibial trial insert 1 12,5 mm Tibial trial insert 2 10 mm Tibial trial insert 2 12,5 mm Tibial trial insert 3 10 mm tibial trial insert 3 12,5 mm tibial trial insert 4 10 mm tibial trial insert 4 12,5 mm femoral / Patellar drill with stop 21

24 ACS Instrument container upper tray REF Instruments femoral guide positioner 10mm GIS spacer block GIS spacer block adapter GIS spacer shim 12,5mm GIS spacer shim 15mm GIS spacer shim 17,5mm GIS spacer shim 20mm GIS femoral sizing template 1 / femoral Sizing Template 2,5 / femoral Sizing Template 4 / ACS initiator drill 9 mm intramedullary rod without stop ic adapter ic T-handle femoral alignment stylus GIS ACS Instrument container lower tray REF Instruments femoral resection block 1 GIS femoral resection block 2 GIS femoral resection block 2,5 GIS femoral resection block 3 GIS femoral resection block 4 GIS distal femoral cutting block 3 GIS distal femoral cutting block 4 GIS distal femoral cutting block 5 GIS distal femoral cutting block 6 GIS distal femoral recutting block 2 GIS femoral alignment guide GIS femoral chamfer block 1 GIS femoral chamfer block 2 GIS femoral chamfer block 2,5 GIS femoral chamfer block 3 GIS femoral chamfer block 4 GIS handle 22

25 ACS Instrument container tray REF Instruments ACS patella trial 26 mm ACS patella trial 29 mm ACS patella trial 32 mm ACS patella resection guide 1,5 mm ACS patella clamp Patella drill bit 26mm + 29mm Patella drill bit 32mm slap hammer ACS patella femoral groove trial ACS femoral trial left ACS femoral trial right ACS tibial trial insert 5 10 mm ACS tibial trial insert 5 12,5 mm ACS femoral chamfer block 5 GIS ACS femoral resection block 5 GIS Literature [1] Huber J., Refior H, J. wear test, Ludwig Maximilians-Universität München Labor für Biomechanik und Experimentelle Orthopädie, Germany, 2002 data on file. [2] Feng E.L., Stulberg S.D., Wixson R.L. Progressive Subluxation and Polyethylene wear in total knee replacements mit flat articular surfaces. Clin. Orthop. and Rel. Res, 299, Feb [3] Eng G.A., Dwyer K.A., Hanes C.K. Polyethylene Wear of Metal Backed Tibiakomponentes in Total and Unicompartmental Knee Prostheses. J. Bone Joint Surgery, 74-B;9, [4] Lewis P., Rorabeck C.H., Bourne R.B., Devane P, Posteromedial Tibial Polyethylene Failure in Total Knee Replacements. Clin. Orthop. and Rel. Res, 299, Feb [5] Collier J, Mayor, M.B., McNamara, J.L., Suprenant, V. A., Jensen, R.E., Analysis of the failure of 122 Polyethylene Inserts from unzementpflichtig tibial knee components, Clin. Orthop and rel research, 273, December [6] Dr.Ing habil Franke, Dipl. Ing. Steffen Vater. Institut für Materialforschung und Anwendungstechnik (IMA): Prüfbericht: Untersuchungen zum tribologischen Verhalten an drei unterschiedlichen Kniegelenkendoprothesen (A219/ ) 23

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