DOC2657 Technique Opératoire SKS - Anglais

OPERATIVE TECHNIQUE SKS

Total Knee Replacement

DOC2657

www.aston-medical.com

1: Alignment rod A30049 + A30124 2: Centromedullary rod A40224

4: T-handle A40232

6: Femoral measuring device A40411 + A40414 7: Drill bit for cutting block A40282

8: Femoral valgus measuring device A40216 9: 3.5-mm screwdriver A32224

10: Distal femoral cutting guide A40223

11: Support A40217 13: Alignment handle A40264

14: Spacer A40186 to A40189 15: Femoral cutting block A40437 to A40442

16: Inspection scythe A40402 18: 8 mm dia. drill bit for centromedullary hole A32229

31: Rotation wedge A40354 + A40355

35: Half-round rasp A40281 41: Stem drill bit A33636

Femoral preparation A40577

1

2

5

3: Femoral extractor / impactor A35539 + A35678

5: Femoral impactor A32225 24: Trial tray impactor A34229

25: Tray impactor A32338

27: Tibial insert impactor A32227 29: Weighted extractor A32186

32: Box of pins A40301 39: Punch dia. 12 A33632

40: Punch dia. 15 A33631

Impaction A40580

Tibial preparation A40579

21: Extra-medullary alignment guide A34204 + A34205

22: Malleolar clamp A40329 23: Spanner A40008

26: Tibial insert extractor A30060

28: Tibial feeler A34995 30: Tibial cutting guide A34203

33: Impaction tube A34248 34: Nail extraction pliers A33668

37: Tibial punch guide A33630 38: Jig bushing A40383

43: Trial tray A33620 to A33626

48: Bracket A34208 51: Tibial slope adjustment piece A34220

53: Extra-medullary guide A40385

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45: Patella pliers A35587 46: Trial patella A4019X + A4060X

47: Patella measuring device A40241 49: Patella drill bit A30083

50: Patella cutting pliers A35413

Patella preparation A40578

OPTION: Uncemented patella preparation A40927

A: Clamp body A40929 B: Gripper A40932

C: Cutter A40934

D: Cutter body A40949 E: Cutter driver A40935

I: Patella press A40942 J: Spanner for eyelet cutter A40933

Anterior stabilised trial condyles A40575

17: A/S trial condyle A40594 to A40605

19: Trial condyle drill bit A30033

44: A/S trial insert A40535 to A40573

Deep dish anterior stabilised trial inserts A40837

Including 17: A/S trial condyle A40594 to A40605

19: Condyle eyelet drill bit A30033

61: Deep dish A/S trial insert A40793 to A40824

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Deep dish rotating trial pieces A40840

Including 17: A/S trail condyle A40594 to A40605


62: Rotating deep dish trial insert A40863 to A40871

and A40951 to A40953

64: Rotating trial tibial tray A40901 to A40905

Including 17: A/S trial condyle A40594 to A40605


63: Mobile trial insert A40726 to A40753 65: Mobile trial tibial tray A40786 to A40789

Mobile trial pieces A40838

Posterior stabilised trial pieces A40576

12: Cutting guide - P/S condylar frame A402XX

20: P/S trial condyle A40195 to A40206

42: P/S trial insert A40146 to A40184 19: Trial condyle drill bit A30033

OPTION: Femoral condyle rotation system A40926

66: Spacer A40906 to A40908

67: Wedge (thickness 0) A40938 68: Wedge (thickness 1, 2, 3, 4 and 5 mm) A40909 to A40912

69: Measuring device A40916 71: Pliers A40950

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TIBIAL CUT – Centromedullary guide

Drilling the centromedullary hole at the foot of the ACL using the 8 mm diameter drill bit (18) or slightly

offset according to the pre-operative plan.

Important checks to perform before setting up the tibial guide: • check that the 0 lines for valgus varus match (unless the tibia needs to be corrected in varus

valgus), and check the hole where the nail must enter (neutral position)

• check that the posterior slope matches the planified slope Introduction of the centromedullary rod (2) using the handle (4).

Remove the handle and position the bracket (48) without fully impacting it so that the rotation can be adjusted subsequently.

Join the two tibial cut elements: cutting guide (30) and adjustment piece (51), and slide the assembly onto

the bracket. Adjust the tibial posterior slope using the cursor D according to the pre-operative plan, or leave the cursor

free and adjust the slope by inserting the scythe (15) or a saw blade in the slot of the tibial cutting guide (3) and applying it to the least worn plateau, so that follow the natural slope of the tibia.

Adjust the tibial guide in rotation according to the tibial axis using the

extramedullary alignment rod (21), reference mark centred between the

two malleoli. Impact using the impaction tube (33).

Place the needle feeler (28) either at -9 on the least worn plateau, or at 0

at the bottom of the cup on the more worn side. This measurement must

be taken in the posterior third, which corresponds to the cup of the prosthetic insert.

Note: If the wear is less than 9 mm, it is preferable to feel on the sound side to perform a 9-mm cut.

Otherwise, feel on the worn side at 0 mm to preserve the bone mass.

Impact the two headless pins in the 0 reference holes, after drilling, and immobilize

the assembly using a headed nail in the most external inclined hole. Loosen and remove locking screw from the cutting block.

Disimpact the tibial guide assembly using the weighted disimpactor. Only the tibial cutting block remains in position.

Perform the tibial cut in the upper slot.

Remove the cutting guide, temporarily leaving the two headless pins in position (in the event that a secondary re-cut is necessary).

TIBIAL CUT – Extra-medullary guide

The aim of the guide is to position the extra-medullary rod parallel to the medullary axis of the tibia (21).

The longest tip of the tibial guide must be slightly posterior to the medullary axis. The posterior slope is provided by the movement of the cursor (identical to the

centromedullary guide). The two tips of the tibial guide shall not be fully impacted until the entire guide is

correctly positioned.

The rest of the procedure is identical to the technique for the centromedullary guide (feeler, mounting the cutting block, etc.).

TIBIAL CUT – Mixed guide The intra- and extra-medullary guides can be combined.

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FEMORAL DISTAL CUT

Knee in flexion:

Remove all osteophytes that could interfere with the evaluation of the centromedullary drill bit entry point. This entry point must be located above the ligament inside the insertion of the PCL, in the middle of the

intercondylar notch. It may be slightly to one side according to the pre-operative tracing, or enlarged so that the centromedullary rod is centred on the diaphyseal part.

Insert the 8 mm diameter drill bit.

To prevent slippage, the entry point can be marked using an awl.

Introduction of the centromedullary rod (2) using the T-handle (4) in the previously drilled channel. Leave the rod in position and remove the handle.

Program the femoral valgus angle determined previously.

• Loosen screw • Press Pad

• Align the part according to the side concerned • Tighten screw

Mount the distal femoral cutting guide (10) on its support (1), the

latch (11b) used to position the resection block for a standard 8 mm

cut. It is always possible to raise or lower the resection level by lifting the

latch and positioning the cutting block opposite the graduation corresponding to the level of the desired cut.

Immobilize by tightening screw A.

Mount the assembly (10) and (11) on the femoral valgus measuring device (8) by pressing latch B.

Place the assembly on the centromedullary rod already installed.

The rear pads of the part (8) must be roughly parallel to the posterior edges of the condyles.

• Impact the two tips

• Lower the cutting block (10) into contact with the anterior femoral cortical line: This operation is performed by pressing

latch.

The valgus angle can be checked using the alignment rod (1) and an

extramedullary rod that must correspond to the center of the head of the femur.

Immobilize the assembly using the headless pins C in the passages

marked with an awl. Place two other headed pins in the inclined

immobilization holes B. The distal cut can be modified by changing the position of the cutting

block in the pins C by plus or minus 2mm, after checking the level of the cut using the scythe (16).

Note: The headed screws B must be removed to reposition the cutting block.

Loosen screw A, and then extract the centromedullary rod using the handle (4).

Remove the assembly (11+8) using the weighted impactor (29) and leave the distal cutting guide in position

(10).

Perform the distal cut. Remove the headed pins B. Remove the cutting block (10).

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CHECKING

Place the knee in extension.

Check the stability in extension using the spacer (14) corresponding to the tibial resection: 9, 11, 13 or 16mm.

FEMORAL ROTATION

• Place the knee at 90° flexion. • Place the locking screw of the sliding arm on the side opposite the

patella.

• Possible determination of an external rotation of the femoral part via the rotation wedge (31) placed under the external condyle.

• Press the measuring device (6) firmly onto the distal cut with the rear pads seated both on the tibial plateau and under the posterior

condyles. • Adjust the feeler on the anterior cortical line. This adjustment must

correspond to the size of condyle measured:

1- Place the feeler in the median position 2- After the first measurement, place the feeler on the size measured

at the sliding arm - Lower the sliding arm until the feeler comes into contact

with the anterior cortical line.

- Tighten the screw of the sliding arm on the chosen size. The point where the feeler touches corresponds to the exit point of

the blade for the anterior cut. Impact the pegs secured to the block and, if necessary, impact two

pins in the holes B.

OPTIONAL - Femoral condyle rotation system

- Need to start the operation with the tibial cut. - Perform the usual distal femoral cut.

- Position the spacer (66) at 90° flexion to check the space 9, 11, 13, or 16 mm using removable shims.

- Measure in extension.

- Position the internal wedge (thickness 0 mm) and the external wedge (thickness 0 mm). (67)

- Rotate the condyle by lifting the femur moderately to tighten the lateral ligaments. - This allows the gap under the external condyle to be evaluated.

- Position a wedge (68) under the external condyle to eliminate any gap.

- Insert the body of the measuring device (69) in the central groove.

- Evaluate the size, tighten the knob (70) and drill the reference eyelets of the 4-in-1 cutting guide.

Drill the two holes (7); write down the reference for the size of the condyle.

size

reference eyelets

external rotation

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Impact the cutting block corresponding to the size of the condyle recorded previously into the corresponding

holes. Immobilize the cutting block using two headed pins in the angled side holes.

Perform the cuts: • posterior cut (posterior chamfer)

• anterior cut (anterior chamfer)

Extract the two headed pins using the weighted extractor.

FEMORAL CUT

Extract the lateral headed pins. Extract the cutting block.

Conservation version

Machine the anterior bridge at the throat of the trochlea using the rasp (35).

Posterior stabilised version Perform the posterior stabilised cage cut:

• Centring of cutting block (1) • Insertion of the angled lateral pins, possibility of inserting the upper nail

if necessary

• Execution of lateral cuts, bottom of cage and trochlea chamfer

CHECKS

• Approach the tray to the cut to check coverage.

• Tray size selection. • Positioning of the test insert mounted on the tray.

• Positioning of the condyle. • Extension.

Possibility of checking the axis of the tray using the extra-medullary rod (1) mounted on the tray holder (13).

Possibility of securing the tray, with knee extended, using two headed pins

in the tray (holes at 45°).

Mark the position of the tray on the tibia using an electric

scalpel.

Drill the condyle eyelets using the drill bit (19).

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PREPARATION OF THE TIBIAL STEM

Extract the test condyle.

Detach the test tray from the test insert. Reposition the tray (if it has not already been secured).

Impact the punch guide block (37). Extract the anterior pins at 45° (if any).

Only if the tibia has a high density, drill along the axis of the stem using the 12 mm diameter

drill bit and the jig bushing (38) mounted on the punch guide (37).

IMPORTANT NOTE: Punch the stem using the 12 mm diameter punch (40) if the tray size is S, SM, M or ML. For

sizes L, LXL and XL, the 15 mm diameter punch should be used (39).

PATELLA REPLACEMENT : recommended with this prosthesis

CEMENTED PATELLA

Choice of patella diameter.

The desired resection height is carried over to the patella cutting pliers (50), theoretical height of the

cut, using the knob 50 B:

• ø 30, t=7 • ø 33, t=8

• ø 36, t=10 • ø 39, t=13

• ø 41, t=15

Perform the cut.

Place the test patella (46) in position.

Introduce the electric scalpel into the central hole A to position the central patella pin.

Positioning of the patella pliers (45) to drill (49) the

patella hole. Centre on the mark made using the electric scalpel.

(These pliers are also used to hold the permanent patella in position whilst the cement is setting.)

UNCEMENTED PATELLA

Clamp mounting

(54) Clamp body (A) Ring 1

(55) Gripper (B) Ring 2 (56) Eyelet cutter (C) Tightening screw

(57) Cutter body (D) Locking screw (58) Cutter driver

push to mount the cutter

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Using the clamp

- Tighten the clamp on the patella and lock it using the screw (C).

- Lower the cutter to bring it into contact with the patella.

- Turn ring 1 (A) to position 25 opposite the mark.

- Lower ring 2 (B) to bring it into contact with ring 1 (A).

- Turn ring 1 a quarter turn to position 0.

- The gap created corresponds to the thickness

to be cut.

- Mount the drill on the shaft and drill the patella by lowering the cutter until it comes into contact

with the ring (A).

- Remove the cutter driver assembly (58) by loosening the screw (D).

- Position the permanent patella flat on the reamed bony patella.

- Mount the patella press (59) and impact the

patella using the handle.

OPTION: Navigation

Possibility of navigating the cuts (tibial and distal femoral) using a navigation system. The SKS implant data are integrated in the software.

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NOTES :

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NOTES :

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NOTES :

Operating technique suggested for reference purposes compiled on the basis of techniques used by the surgeons who designed the prosthesis This document is not available for the US market.

Manufacturer : Aston Medical – France – Tel 33 (0)4 77 93 00 04 – Fax 33 (0)4 77 74 35 93

Z.I. Montreynaud – 19 rue V. Grignard - 42000 Saint-Etienne

Documents

DOC2657 Technique Opératoire SKS - Anglais