Aesculap Univation X Surgical Technique

univation

™

X

Unicondylar Knee System Surgical Technique

Aesculap Orthopaedics

2

univation

™

X Unicondylar Knee System

Surgical Technique

Table of Contents

I. System Overview ......................................................3

II. Indications, Contraindications, Warnings and Potential Risks & Precautions .....4

III. Preoperative Planning ..................................................6

IV. Approach ............................................................7

V. Instrument Assembly Instructions ........................................8

1. Extramedullar Tibial Alignment ........................................8

2. Femur Trial Insertion Instrument .......................................9

VI. Workow Synopsis ...................................................10

VII. Surgical Technique ...................................................11

1. Tibia Alignment ....................................................11

2. Tibia Resection ....................................................13

3. Measuring Flexion and Extension Gaps .................................14

4. Femur Preparation ..................................................16

a. Distal Cut .......................................................18

b. Chamfer and Posterior Cuts .........................................18

5. Tibia Sizing and Preparation ..........................................20

6. Implant Sizing and Final Preparation ..................................24

7. Trial Reduction and Implant Final Components ..........................26

8. Trial and Final Implant ..............................................28

9. Cementing Technique ...............................................29

10. Closure ..........................................................29

VIII. Implants Overview ....................................................30

IX. Femur/Tibia Compatibility .............................................30

X. Instrument Overview ..................................................30

Saw Blades ..........................................................35

Table of Contents

3

The univation™ X Unicondylar Knee System was designed with a xed platform to treat

medial knee defects. The system oers streamlined, user-friendly instrumentation

to optimize surgical time and allow for intra-operative exibility. The univation X

system is an enhanced design with ecient instrumentation to help restore natural

knee kinematics.

Design Advantages:

■

Advanced Surface Technology: All univation X knee components are created

with the 7-layer Advanced Surface technology, which makes the system the rst

choice for surgeons and patients alike.

■

Anatomic Implant Fit and Design: With 5 femoral sizes and 6 tibial sizes there are

over 30 possible implant combinations. The design of each component addresses

the various needs of the natural anatomy of the patient while providing optimal

bone coverage and minimal bone resection.

■

Gap Balancing Technique: Aesculap’s innovative gap balancing instrumentation

allows the surgeon to manage the gap before the distal cut is made. The

instrumentation and technique also permits gap management by resecting the

posterior condyles as well.

■

Stability and Bone Preservation: univation X is a xed platform with a peg

design that oers optimal primary stability with minimal cuts to preserve bone.

There are three sizes that have identical cuts allowing the surgeon intra-operative

exibility.

■

IQ Instrumentation Platform: Instrumentation is part of the Intuitive & Quick (IQ)

platform, which is designed to create eciency in the operating room (OR) through

a streamlined workow, improved ergonomics and familiar instrumentation, all

with reproducible results. This is accomplished through:



Reduced instrumentation



Ergonomic handles



Fast-acting lock mechanisms



Color-coded instruments and trays

■

Ecient Reprocessing: univation X IQ instruments are stored in modern and

simple wash trays for eciencies in reprocessing. Instruments can remain in the

tray during cleaning for fast sterilization intended to save time and money in the

Central Sterile Supply Department (CSSD). Note: Complex instruments such as

incision guides require manual precleaning.

I. System Overview

4

univation

™

X Unicondylar Knee System

Surgical Technique

Indications for Use

The univation X Unicompartmental Knee System is indicated for cemented use only in patients undergoing surgery for a severely

painful and/or disabled joint damaged as a result of osteoarthritis, traumatic arthritis, or a failed previous implant when only one

condyle of the knee (medial) is aected.

Contraindications

Contraindications include, but are not limited to:

■

Presence of fever, infection or inammation (systemic or localized);

■

Morbid obesity;

■

Pregnancy;

■

Mental illness or drug abuse

■

Severe osteopenia (or any medical or surgical condition) which would preclude potential benets of implants;

■

Suspected or documented metal allergy or intolerance;

■

Mixing of implant components from other manufacturers;

■

Any case not listed in the indications; and

■

Patients unwilling or unable to follow post-operative care instructions.

Warnings

■

The univation X implants are designed for single patient use only and must never be reused. As with all other orthopedic

implants, the univation X components should never be re-implanted under any circumstances.

■

The mixing of dierent manufacturer implant components is not recommended due to metallurgical, mechanical and functional

reasons. Dissimilar metals in contact with each other can accelerate the corrosion process due to galvanic corrosion eects. Do

not use implants or instruments from other systems or manufacturers, and do not mix cobalt-chromium and titanium implant

components together in a total knee system.

■

The univation X implants can become loose or break if subjected to increased loading. Factors such as the patient’s weight,

activity level and adherence to weight-bearing or load-bearing instructions can aect the implant’s longevity. Damage to the

weight-bearing bone cement and/or bone structures caused by infection can give rise to loosening of the components and/or

fracture of the bone.

■

The univation X Unicompartmental Knee System has not been evaluated for safety and compatibility in the MR environment. The

univation X Unicompartmental Knee System implants have not been tested for heating or migration in the MR environment.

■

These warnings do not include all adverse eects which could occur with surgery, but are important considerations specic

to metallic devices. The risks associated with orthopedic surgery, general surgery and the use of general anesthesia should be

explained to the patient prior to surgery. See the complete indications for use provided with the product.

II. Indications, Contraindications, Warnings and Potential Risks & Precautions

5

Precautions

■

The univation

™

X Unicompartmental Knee System is intended to be used by surgeons specializing in orthopedic surgery who have

a thorough knowledge of knee arthroplasty, joint morphology and the biomechanical principles of the knee.

■

Pre-operative assessment of the suitability of the patient’s anatomy for accepting implants is made on the basis of X-rays, CT

scans and other radiological studies.

■

Only patients that meet the criteria described in the Indications for Use section should be selected.

■

Correct selection of the implant is extremely important. The morbidity as well as patient weight height, occupation and/or

degree of physical activity should be considered.

■

Proper implant handling before and during the operation is crucial. Handle the implant components properly. Ensure

packaging integrity for implant sterility. Do not use any implant where the packaging has been breached. Do not resterilize an

implant. Do not allow the implants surfaces to be damaged.

■

Adequately instruct the patient. The physician should inform the patient about knee implant advantages and disadvantages,

post-operative limitations, weight/load bearing stresses which could aect bone healing, implant limitations, and the fact that

premature physical activity and full weight/load bearing stresses have been implicated in premature loosening, damage and/or

fracture of knee prosthesis.

II. Indications, Contraindications, Warnings and Potential Risks & Precautions (continued)

6

univation

™

X Unicondylar Knee System

Surgical Technique

For every knee arthroplasty, careful pre-operative X-ray

planning is recommended.

The size of the femoral component is determined in the

X-ray before the surgery. To do this, X-ray templates are

available in dierent scales.

The contours of the implant partly project up to 2 mm over

the bony edge and therefore replace the cartilage.

The tibial component should also be determined, but the

size of the tibia can easily be determined intra-operatively.

The tibial slope of the tibial component should correspond

as closely as possible to the natural slope of the patient. For

this reason, it is also determined from the X-ray image.

The following images are required for X-ray analysis:

■

Knee joint in AP projection (Fig. 1)

■

Knee extended

■

Centered over the distal patella

■

Knee joint in lateral projection (Fig. 2)

■

Knee 30° exed

■

Centered over the distal patella.

■

Ideally for tibial slope: long leg image in lateral

projection.

The results of preoperative planning should be documented

in the patients le and available during the operative

procedure for reference.

Fig. 2

Fig. 1

III. Preoperative Planning

Note: Place the dotted line of the femoral template in

parallel to the longitudinal axis of the femur. The femoral

templates are designed so that the dotted line is parallel

to the lengthwise axis of the femur. Please note that the

femoral pegs do not run parallel to the longitudinal axis.

The posterior edge of the implant should not project over

the posterior edge of the condyle.

7

IV. Approach

At 90° exion, make a paramedial skin incision from the

medial edge of the patella to a point 2 to 3 cm distal of the

joint line. (Fig. 3) The incision point descends through the

joint capsule. At its cranial end, extend the capsule incision

about 1 to 2 cm tilted from the medial into the musculus

vastus medialis. For a better view, remove part of the

retropatellar fat pad (Hoa’s fat pad). The surgeon should

decide the overall length of the incision based on each

patient and what is required for proper visualization of the

knee anatomy.

All osteophytes must be removed from the medial edge

of the medial condyle as well as from the intercondylar

notch and in the posterolateral area of the medial condyle.

Dierent exion positions of the leg can be used to reveal

all the remaining osteophytes through the moving incision

window.

Fig. 4

Fig. 3

Caution: Careful consideration must be made to not

damage the suprapatellaris recess/bursa

Medial parapatellar Arthrotomy

With the knee in exion or extension, the arthrotomy is

performed starting proximal to the superior pole of the

patella, incising the rectus femoris tendon longitudinally.

(Fig. 4) Continuing the arthrotomy distally around the

medial aspect of the patella, and ending medial to the tibial

tubercule is then carried out.

8

univation

™

X Unicondylar Knee System

Surgical Technique

■

Press and hold the button on the

bimalleolar clamp.

■

Guide the holder for the

bimalleolar clamp into the groove.

■

After the neutral position has been

reached, release the button.

■

Turn the wheel on the tibial

alignment handle to the open

position, in which it shows 'OPEN'.

■

Place the handle onto the holder

for the bimalleolar clamp.

■

Adjust to the neutral position.

■

Press and hold the handle

adjustment wheel to release the

locking mechanism.

■

Insert the holding rod for the

resection block into the handle.

■

After reaching the desired height,

release the wheel.

■

Turning the wheel will allow a ne

adjustment to the height.

1 2 3

■

Connect the support rod to the

right or left tibial resection block.

■

Lock the assembly using the front

wheel.

■

Insert the rod into the sleeve and

tighten the xation screw.

4 5

V. Instrument Assembly Instructions

1. Extramedullar Tibial Alignment

9

1

2

3

■

Insert the implant holder with

the thread into the sleeve of the

femoral holder.

■

Place the insertion instrument

with both pins parallel to the trial

implant. Place rm pressure on

the implant and click it into place.

■

The femoral trial holder is xated

to the trial using a rolling motion.

Using rm pressure, start with the

lower pin and roll upward.

■

Tighten the holder onto the

femoral trial.

2. Femur Trial Holder Instrument

10

univation

™

X Unicondylar Knee System

Surgical Technique

VI. Workow Synopsis

1

2

3

4 5

6

7 8

1. Tibial alignment and proximal tibia

resection

2. Measuring exion and extension gaps

3. Femur preparation

4. Femur anterior and posterior cuts

5. Tibia sizing

6. Implant sizing and nal preparation

7. Trial reduction and implant nal

components

8. Trial and nal implant

11

Fig. 6

Fig. 5

VII. Surgical Technique

1. Tibia Alignment

Extramedullary Alignment

■

The extramedullary (EM) alignment system assembly is

placed parallel to the front of the tibia with the leg in

exion.

■

The bimalleolar clamp, previously placed in the neutral

position, is xed around the lower leg just above and

centered around the ankle joint.

Height Adjustment

■

Using the cutting check plate, the height and posterior

slope of the resection can be checked.

■

If necessary, the resection height can be adjusted using

the wheel for the height adjustment. The goal is to

remove any defect of the tibial plateau so that the tibial

implant lays on intact bone for optimal implant support.

■

Depending on the resection method, either through the

sawing slit or on the block, the resection height must be

appropriately adjusted.

A: Bimalleolar clamp NS345R, B: Holder for bimalleolar clamp NS344R, C: Tibial alignment system NS342R, D: Holding rod for tibial resection block

NM583R, E: Tibial resection block right/left NM585R/NM584R, F: Cutting depth check plate NS850R

A B C D E F

Note: When aligning it parallel to the axis of the tibia

(2 and 3 nger rule), a tibial slope of 5° is pre-adjusted.

12

univation

™

X Unicondylar Knee System

Surgical Technique

1. Tibia Alignment (continued)

Varus-valgus Alignment

■

Push the knob (1) on the bimalleolar clamp and slide

the alignment system medially or laterally to adjust the

varus/valgus of the proximal tibial resection. The distance

between the laser-marked lines on the scale corresponds

to a deviation of 1° for a tibia length of 40 cm.

Alignment of the tibial slope

■

Releasing the xation wheel (2) on the lower part of

the alignment system (by turning the screw to OPEN)

allows the alignment system to be shifted in the anterior

direction to increase the slope of the proximal tibial

resection. The distance between the laser-marked lines

on the scale corresponds to a deviation of 1° for a tibia

length of 40 cm.

Fig. 8

Fig. 7

1

2

A: Bimalleolar clamp NS345R, B: Holder for bimalleolar clamp NS344R, C: Tibial alignment system NS342R,

D: Holding rod for tibial resection block NM583R, E: Tibial resection block right/left NM585R/NM584R

A B C D

E

■

Fasten the tibial cutting guide with two headless pins

through the two lowest marked pinholes to the bone. To

secure the resection block, a third pin can be inserted in

the convergent pin holes.

13

2. Tibia Resection

Step 1:

■

The horizontal tibia cut is made either through the

cutting guide (Fig. 9) or on top of the cutting guide

(Fig. 10). In either approach ensure the blade reaches the

back of the joint.

Step 2:

■

Using the reciprocating saw blade, make the vertical

tibial cut. The cut should be made slightly medial to the

origin of the anterior cruciate ligament.

■

Point the saw blade towards the femoral head in the

direction of the femoral axis as shown in (Fig. 11).

Fig. 10

Fig. 9

A: Headless pins 63 mm NP583R, B: Pin driver NP613R, C: Acculan

®

drill, D: Acculan saw, E: Acculan reciprocating saw

A B DC E

Note: The dierence in height from the top of the

cutting guide to the cutting guide slot is 4 mm.

Caution: The protection of the

surrounding soft tissue of the

knee joint is critical. Special

attention and necessary retractor

instruments should be used to

protect this during the tibia

resection.

Fig. 11

■

Tip: The vertical/sagittal cut should

not extend below the transverse/

horizontal cut.

■

You can now use the necessary

instrumentation to excise the

resected tibial plateau.

14

univation

™

X Unicondylar Knee System

Surgical Technique

3. Measuring Flexion and Extension Gaps

Measurement with Spacers

■

The exion gap is measured with the spacers. Please note

that the exion gap is measured with the leg hanging. To

do this, an assistant must lift the upper thigh slightly. The

thickness of the spacer is correct if it can no longer be

shifted and pushed in and out while holding it with two

ngers.

Fig. 12

Fig. 13

A: Trial Spacer NM651R – NM653R, B: Gap distractor for femoral-tibial distractor NP609R, C: Femoral alignment guide NP894R

A B C

■

The minimum height for the tibial plateau and meniscus

component is 7 mm. If the 7 mm spacer does not t, the

tibia must be resected again.

Caution: Before extending the leg for measurement of

the extension gap, remove the spacer to avoid injury to

the ligaments.

Optional: Instead of the spacer, a distractor can be used to

measure the gaps. To do this, use the spreader in exion and

extension and apply the same force. The size of the gap can

be read o the instrument.

Note: In some cases, the cement thickness causes the

meniscus components to be inserted about 1 mm higher

than planned. Therefore, it is recommended that the joint

gap is resected to at least 8 mm.

15

■

Flexion and extension gaps must be balanced for optimal

post-operative results.

■

The resection height can be adjusted either through the

distal cut (distal cutting block) or through the posterior/

chamfer cut (2-in-1 cutting block), by setting the blocks

to the corresponding level on the spacer. At “0”, the gaps

are not changed. At +1, +2, the cut is increased. At -1,

-2, the cut is decreased.

Gap Balancing Strategies

Scenario Option 1 Option 2

Flexion Gap

= Extension

Gap

Both resection blocks

are set to ‘0’. The

implant thickness is

resected.

Extension

Gap >

Flexion Gap

The extension gap

is adjusted to the

exion gap. There is

less resection in the

distal cut. The distal

cutting guide is set at

-1 or -2.

The exion gap

is adjusted to the

extension gap.

There is more

resection in the

posterior cut

(2-in-1 cutting

guide). The

2-in-1 cutting

block is set to

+1 or +2.

Extension

Gap <

Flexion Gap

The extension gap is

adjusted to the exion

gap. There is greater

resection distally than

posteriorly. Cutting

block is set to +1 or

+2.

On the 2-in-1

cutting guide,

that is the

posterior cut,

no less can be

resected.

Fig. 15

Fig. 14

A: Distal cutting guide NM540R, B: Femur 2-in-1 cutting guide left/right NM006R – NM011R

A B

16

univation

™

X Unicondylar Knee System

Surgical Technique

4. Femur Preparation

a. Distal Femur Cut

■

Place the distal femur cutting guide onto the trial spacer

with the leg placed in extension.

■

For alignment to the mechanical axis, the rod and

the adapter are attached to the spacer. The rod points

towards the femoral head.

Fig. 17

Fig. 16

A B C

A: Trial Spacer NM651R – NM653R, B: Distal femur cutting guide NM540R, C: Femoral alignment guide NM560R,

D: Alignment check rod with sleeve NE331R, E: Alignment check rod NP471R

ED

■

Fasten the cutting guide with two headless pins. Be sure

that the cutting guide is in contact with the distal and

anterior condyle.

Note: The distal cutting guide should slide easily along

the spacer tool.

17

■

Before resection, remove the spacer and bring the knee

to 90° exion.

Fig. 19

Fig. 18

A B C

D

E F

A: Headless pins 63 mm NP583R, B: Pin driver NP613R, C: Acculan

®

drill, D: Tibial preparation plateau T1-T6 NM591R – NM596R,

E: Acculan reciprocating saw, F: Femoral size determination guide NM667R

Caution: The tibial plateau must be protected during

resection using the tibia preparation plate.

Femoral Sizing

■

It is recommended to measure the femur size on the

X-ray. The posterior part is dicult to assess

intra-operatively. The femur sizer is used to determine

the size of the femur component.

■

Place the femoral sizer onto the spacer with the side

marked “F” for xed version (facing outward). The sizer is

placed onto the previously planned level of the spacer.

■

The femur sizing instrument measures the anterior

section of the femoral component shield. The distal

resection should also be covered as much as possible.

Note: The spacer contains ridges on the side which

corresponds to the femoral size. The sizer should be

placed at “0” and slide forward. Careful attention should

be made to ensure the femoral size guide is placed on the

same groove on both sides of the spacer.

Note: Please make sure you can read “F” on the femoral

sizer.

18

univation

™

X Unicondylar Knee System

Surgical Technique

Fig. 20

4. Femur Preparation (continued)

b. Femur Chamfer and Posterior Cuts

■

Place the 2-in-1 cutting guide onto the spacer with the

knee in 90° exion.

■

The 2-in-1 cutting guide is placed ush against the distal

surface and posterior condyle.

Fig. 21

A: Trial Spacer NM651R – NM653R, B: Femur 2-in-1 cutting guide left/right NM006R – NM011R

A B

■

Based on the tibia cut, the rotation of the femur is

adjusted. In the case of a medial or lateral overhang of

the cutting guide, translation in the medial/lateral plane

can be adjusted.

Note: Protection of the surrounding soft tissue of the

knee joint is imperative! We recommend the use of

Hohmann or collateral retractors for protection.

19

■

The resection block is fastened with two headed pins. The

anterior pin is 30 mm long (NP585R), and the posterior

pin is 50 mm long (NP586R).

Fig. 23

Fig. 22

A: Headed pins 30 mm NP585R, B: Headed pin 50 mm NP586R, C: Pin driver NP613R, D: Acculan

®

drill, E: Tibial preparation plateau

T1-T6 NM591R – NM596R, F: Acculan saw

A

B C FD

■

Make the posterior cut rst, then the chamfer cut is

made.

Note: Either the trial spacer or tibia preparation plateau

should be used to protect the tibia.

E

20

univation

™

X Unicondylar Knee System

Surgical Technique

Fig. 24

Fig. 25

5. Tibia Sizing and Preparation

■

Use the hook to measure the AP dimension of the tibia

and tibia implant size.

A: Tibial size measurement instrument AP NM903R, B: Tibial preparation plateau T1-T6 NM591R – NM596R

A B

■

Place the corresponding size tibial plate on the tibial cut.

The plate should not overhang on the sides. If necessary,

a new sagittal cut should be performed to enlarge the ML

surface. It is important during this process to keep the

footprint of the cruciate ligament intact.

Page is loading ...

Aesculap Univation X Surgical Technique

Aesculap Univation X Surgical Technique

Other documents