Smith & Nephew Syncera Anthem User manual

Surgical Technique

In consultation with:
Professor T.K. Kim – Seoul, South Korea
Professor D. Saris – Utrecht, Netherlands
Professor R. Tözün – Istanbul, Turkey
Professor Y. Zhou – Beijing, China
Professor A. Belooshi – Dubai, U.A.E.
Doctor M. Wadhwa – Chandigarh, India
Doctor R. McLennan-Smith – Durban, South Africa
Doctor J. Duboy - Santiago, Chile

1
ANTHEM™ PS
Total Knee System
Surgical Technique
Introduction 2
Indications 2
Preoperative planning 3
Femoral preparation 4
Tibial preparation 7
Femoral positioning and sizing 11
A/P and chamfer resection 15
Component trialling 17
Tibial keel preparation 20
Resurfacing patellar preparation 22
Implantation and closure 25
Implant Compatibilities 29

2
Introduction
The ANTHEM™ PS Total Knee System has been designed to offer
orthopaedic surgeons solutions to address a range of intraoperative
situations. Proper implant function is dependant on an extensive
and accurate surgical technique. The ORTHOMATCH™ Universal
Instrumentation system is designed to be used with ANTHEM
to provide an easy to use system that facilitates accurate and
reproducible surgical outcome. The system is designed to
accommodate either a minimally invasive or standard surgical incision
and exposure.
While it is the designers’ objective to develop accurate, easy-to-use
instrumentation, each surgeon must evaluate the appropriateness
of the following technique based on his or her medical training,
experience and the specific patient clinical evaluation.
Indications
Indications for use include rheumatoid arthritis; post-traumatic
arthritis, osteoarthritis or degenerative arthritis; failed osteotomies or
unicompartmental replacement. The ANTHEM PS Total Knee System is
designed for use in patients in primary total knee replacement surgery,
where the anterior and posterior cruciate ligaments are not fully
functional and the collateral ligaments remain intact.
Disclaimer
The following technique guide was prepared under the guidance of
Professor T.K. Kim, Professor D. Saris, Professor R. Tözün, Professor Y.
Zhou, Professor A. Belooshi, Doctor M. Wadhwa, Doctor R. McLennan-
Smith and Doctor J. Duboy. It contains a summary of medical
techniques and opinions based upon their training and expertise in
the field, along with their knowledge of Smith & Nephew products.
It is provided for educational and informational purposes only. Smith
& Nephew does not provide medical advice and it is not intended
to serve as such. It is the responsibility of the treating physician
to determine and utilize the appropriate products and techniques
according to their own clinical judgment for each of their patients. For
more information on the products in this surgical technique, including
indications for use, contraindications, effects, precautions and
warnings, please consult the products’ Instructions for Use (IFU).

M
T
M A
V
6º
3º
3º 3º
3º
3
Preoperative planning
On a full lower limb radiological view determine the
angle between the anatomical and the mechanical
axes. This measurement will be used intraoperatively
to select the appropriate valgus angle so that correct
limb alignment is restored. (Beware of misleading
angles in knees with a flexion contracture or rotated
lower extremities.)
Note: Many surgeons prefer to simply select
a standard angle for the distal femoral cut
(ie, 5º, 6º or 7º) based on the patient and
surgical experience.
Recommended sawblade
Cutting thickness and blade thickness
should be 0.053" or 1.35mm.
M = Mechanical Axis
A = Anatomical Axis
T = Transverse Axis
V = Vertical Axis

a
b c
4
1. Open the femoral canal with the 9.5mm intramedullary
drill. The drill has a 12mm step to open the entry point
further (Figure 1).
2. Assemble the valgus alignment guide with the valgus
bushing (5°,6° or 7°) Right or Left mark facing upwards
to match the correct side (hand) of the knee based on
preoperative planning and assessment of valgus angle.
3. Slide the IM T-Handle rod through the valgus bushing
and in to the femoral canal until the assembled valgus
alignment guide touches at least one of the distal
femoral condyles (Figure 2).
4. Connect the universal cutting block to the valgus
alignment guide with the “F” mark facing upwards and
allow the cutting block to sit in a neutral position within
the trochlea.
5. Use trocar pins to secure the distal femoral cutting
block to the anterior femur through the two holes
marked “0” (Figure 3).
Femoral preparation
Figure 1
Figure 2
Figure 3

5
6. Once the universal cutting block is secured with pins,
remove pins from valgus alignment guide and slide
the valgus alignment guide anteriorly to fully remove it.
Then remove the IM -handle and valgus bushing from
the Intra-medullary canal.
7. Extend the knee fully and insert drop rod guide
assembly in to the blade slot of the universal cutting
block to check Hip Knee Mechanical Axis (HKA) before
resection (Figure 4).
8. By sliding the resection check guide (angel wing) in to
the blade slot of the universal cutting block assess the
bone resection level before performing the resection.
The universal cutting block pinned through the “0”
holes will resect 9.5mm from the prominent condyle of
the femur (Figure 5).
9. If additional bone removal is desired, for example in the
case of a fixed flexion deformity, the universal cutting
block can be shifted superiorly by removing it from the
pins and reinserting it onto the “+2” pin holes. This will
result in a 11.5mm distal resection (Figure 6).
Figure 5
Figure 6
Figure 4

6
10.Once resection level and alignment are determined,
insert a third pin into the angled pin hole to secure the
universal cutting block in position. Resect the distal
femur using an oscillating saw (Figure 7).
11.Once resection complete then remove pins and
the universal cutting block from the femoral bone
and remove the cut bones from the distal condyles
(Figure 8).
Figure 7
Figure 8

7
1. Assemble the 3° cut block connector and tibial spiked
fixation rod to the extramedullary tibial alignment guide
and ankle clamp (Figure 9).
2. Connect the universal cutting block to the 3° cut block
connector with the “T” mark facing outwards. This can
be attached either centrally or medially depending
on preference.
3. Place the ankle clamp around the patient’s ankle
distally, and proximally impact the posterior spike of the
tibial spiked fixation rod into the ACL footprint to secure
assembly (Figure 10).
Tibial preparation
Figure 9
Figure 10

8
4. Align the extramedullary tibial alignment guide parallel
to the tibial axis in the coronal and sagittal planes.
Rotate the assembly to the medial one-third of the tibial
tubercle and impact the anterior spike of the up rod
(Figure 10 and 10a).
Note: 3° of posterior slope is built into the cut block
connector and 4° of slope is built into the articular
insert.
5. Attach the tibial stylus to the universal cutting block by
inserting the foot of the tibial stylus into the cutting slot
of the universal cutting block.
6. Adjust the resection level by lowering the universal
cutting block until the tibial stylus touches the low
point on the less affected side of the tibia. The tibial
stylus can be adjusted for 2mm (affected side) or
9mm (unaffected side) tibial resection by reversing its
position in the cutting slot of the universal cutting block
(Figure 11).
7. Pin the universal cutting block to the tibia by inserting
pins first through the central holes; then the medial
hole (Figure 11a).
Figure 10a
Figure 11
Figure 11a

9
8. Check the posterior slope and resection plane with
resection check (angel wing) (Figure 11b).
9. Remove the extramedullary tibial alignment guide
assembly by loosening the thumbscrews and then
using the slaphammer to remove the spike rod
superiority while the universal cutting block remains in
position with secured pins. The ankle clamp and 3° cut
block connector can then also be removed.
10.Insert drop rod guide assembly into the blade slot of
the universal cutting block in mid line of proximal tibia
to check mechanical axis alignment (Figure 12).
11.Resect the proximal tibia using an oscillating saw
(Figure 13).
Figure 11b
Figure 12
Figure 13

10
12.Remove the universal cutting block from the bone and
clean up the proximal tibial surface (Figure 13a).
Note: If it has not already been removed, excise
completely the entire PCL attachment from the femoral
intracondylar notch with either a cautery or scalpel to
prevent it from affecting the assessment.
13.Extend the knee to 0 degree to check mechanical axis
alignment and extension gap balance. Check alignment
and balance with the appropriate spacer block and rod.
Balance ligaments in standard fashion (Figure 14).
Note: If the extension gap is too tight for a 9mm
spacer, and the distal resection is through the deepest
portion of the trochlear groove, resect additional tibia.
Figure 13a
Figure 14

11
The ORTHOMATCH™ femoral sizing guide allows for
external rotation to be set from 0-9º based on surgeon
preference and patient anatomy. Rotational alignment
may be checked by aligning the A/P axis (Whiteside’s
Line) with the vertical marks on the sizing guide or by
ensuring that the “EPI” lines on the face of the guide
are parallel with the epicondylar axis. Once rotation
is set the guide can be locked by turning the quick
connect handle.
The sizing guide can be used for either posterior
referencing or anteriorly referencing by utilizing either
the “Ant Ref” or “Post Ref” holes. These holes correlate
with similar holes on the A/P resection blocks.
The femoral size is indicated on either side of the
femoral housing of the sizer. In addition, the femoral
stylus is marked with sizing correlating with the femoral
flange length / anterior sawblade exit point.
Femoral positioning and sizing
Stylus marked to indicate anterior femoral
flange length/sawblade exit point
Quick connection handle attaches to sizing
guide for application to resected distal femur
Size reading
Posterior
referencing
holes
Locking knob
Posterior
paddles
Femoral external
rotation guide
(0-9 degrees)
Fixation holes
Anterior referencing
holes
Trans-
Epicondylar
axis (TEA)
A/P axis
(Whiteside’s line)

Posterior Condylar Axis
Epicondylar Axis
AP Axis
12
Sizing steps are as follows:
Optional: Mark the AP and epicondylar axis on the
femur (Figure 15).
a. Place sizing guide onto resected distal femur
b. Pin guide through fixation holes to provide stability
c. Select desired femoral external rotation 0-9deg
d. Note indicated size – if between sizes see sizing step
for more detail
e. Select Anterior or Posterior referencing
f. Pin either anterior or posterior referencing holes with
trocar pins
g. Leave pins in place for femoral cutting block
1. Place the femoral sizer guide flush to the resected
distal femur by using the quick connect handle to
ensure both the posterior paddles of the femoral sizer
guide are in contact with the underside of the posterior
condyles (Figure 16).
2. Secure the guide to the bone through the two pin holes
located at the bottom of the sizing guide (Figure 16a).
Figure 15
Figure 16
Figure 16a

13
3. It is important to use the distal femoral anatomic
landmarks (AP axis and Epicondylar Axis) of the knee to
guide external rotation and to ensure optimized sizing,
ligament balance and patella tracking.
This is commonly set at 3°. However, certain patient
groups have higher external rotation of the femur,
which correlates to a greater degree of tibia vara. In
these patients more external rotation of the femoral
component should be considered (Figure 16b).
Note: Ensure that the appropriate side is chosen when
setting external rotation, ie, “L” for left and “R” for right
4. Once the desired external rotational is set, lock the
sizing guide by rotating the central knob clockwise with
the Quick Connect Handle.
5. In order to determine femoral size, position the stylus
tip just lateral of the anterior trochlear sulcus and slide
the femoral sizer housing down until the stylus touches
the anterior cortex. The size is indicated against the
laser marked “SZ” (Figure 16c).
Figure 16b
Figure 16c

14
6. Slide the femoral stylus backward or forward so that
the size indicated on the femoral stylus matches the
femoral size indicated on the femoral sizer guide.
The point at which the femoral stylus contacts the
bone marks the peak of the femoral anterior flange
(Figure 16d).
7. If between sizes, it is recommended to use the
following protocol depending on preferred referencing
technique.
Posterior referencing
Choose the next larger size (ie, upsize) to reduce the
risk of anterior notching
Anterior referencing
Choose the next smaller size (ie, downsize) to avoid
overstuffing the flexion space
Note: The average difference between sizes of the
ANTHEM™ femoral implant sizes is 3mm.
8. Once implant size and external rotation are determined
place two pins in the appropriate anterior OR posterior
referencing pin holes (not both). Remove the Femoral
sizing guide by sliding it off the secured trocar pins,
leaving the pins in situ (Figure 16e and 16f).
Figure 16d
Figure 16e
Figure 16f

15
1. Select the appropriate size A/P resection block and
place over the pins through the appropriate anterior
or posterior referencing holes. Ensure that the cutting
block is flush with the resected distal femur (Figure 17).
2. Prior to bone resection, insert the resection check
(angel wing) into the anterior blade slot of the A/P
resection block to check the plane of the resection and
to avoid any chance for notching (Figure 17a).
Note: Component size can also be estimated by the
M-L dimension of the cutting block at the condylar
and junctional region. The cutting block M-L width
corresponds to the standard size (not Narrow)
ANTHEM™ femoral component.
AP translations
Should any fine adjustment be required at this stage,
then an option is to use the anterior OR posterior
referencing translation blocks. These are designed
to allow fine adjustment of the A/P position of the
femoral cutting block.
To use the translation block remove the trochar pins,
placing the spikes on the back of the block into the
same location holes used for the A/P cutting block,
and then re-drill pins in the new position. It is useful
to mark the original pin track holes with a marking
pen in order to properly identify the new holes.
Care must be taken when using these translation
blocks as any translation of the cutting block may
affect both the posterior flexion space and patello-
femoral joint space.
3. In order to secure the block there are additional
fixation holes medially and laterally as well as a
central pin hole. Once secure remove the anterior or
posterior referencing pins from the block..
Anterior referencing block Posterior referencing block
Figure 17
Figure 17a
A/P and chamfer resection

16
4. Complete the anterior, posterior and chamfer cuts with
an oscillating saw. The block is designed to allow for
angling of the sawblade during the cuts.
Note: To maintain block stability, the anterior chamfer
cut should be completed last.
5. Once all resection cuts are complete, remove the A/P
Resection Block and remaining pins from the bone.
6. Ensure the knee is flexed to 90 degrees to check
flexion gap balance using the appropriate spacer block
and rod. There should be 1-2mm of laxity laterally only.
The aim is to have equal flexion and extension spaces
(Figure 18, 18a, and 18b).
Note: Surgical tips to achieve optimal flexion:
– Avoid posterior impingement of femoral component
by ensuring adequate size and correct posterior
condylar offset
– Excise the entire PCL attachment from the femoral
intercondylar notch with either a cautery or scalpel
as the PCL has been shown to constrain flexion
assessment
– Use a curved/offset osteotome to remove any
posterior osteophytes
– Correctly balance the flexion gap
– Prevent overhang of the femoral and tibial
components
– Ensure correct tibial slope
– Beware of the neurovascular structures at the
posterior aspect of the knee joint
Figure 18
Figure 18a
Figure 18b

17
1. Flex the knee to 90° and insert the appropriate sized
femoral trial using the femoral trial impactor.
Note: To avoid the trial slipping into flexion, the trial
femoral impactor can also be used as a notch Impactor
by rotating it 180 degrees and impacting the anterior
femoral notch area (Figure 19).
2. The femoral trial should be both fully seated and flush
with the lateral cortex avoiding excessive overhang
on either side of the bone. If overhang is present a
narrow implant can be selected, indicated by the laser
markings either side of the trial.
Note: It is important also to assess the fit of the trial
in the trochlea and trochlea junction area to avoid any
overhang.
3. Secure the femoral trial to the bone using two short
headed pins in the anterior flange (Figure 20).
4. The ANTHEM™ femoral trials are available in either metal
or high grade polymer. If using Metal Trials, insert the
appropriate sized housing collet (size 1-2 or 3-8) to the
trial femoral component by sliding the housing collet
from anterior to posterior in the provided slot.
4a.If polymer femoral trials are used then attach the
collet guide housing first on to the distal surface of the
femoral trial by screwing in the distal screws into the
femoral lug holes. Then slide the appropriate sized
collet guide into the housing from anterior to posterior
(Figure 21).
Component trialling
Figure 19
Figure 20
Figure 21

18
5. Assemble the PS housing reamer by attaching the
housing reamer dome and the PS reamer sleeve to the
reamer shaft. Ream through the PS housing collet in
both anterior and posterior positions until the depth
stop of the reamer contacts the PS housing collet
(Figure 21a).
6. Attach the modular PS box chisel to the modular
handle and impact through the collet guide until flush
with the collet. The chisel should be used anteriorly
and then posteriorly to ensure that the full length of the
PS box is prepared. Remove any remaining bone debris
within the box preparation area.
7. Select the appropriate sized femoral trial PS cam
module (matching the femoral trial size selected).
Insert the arms of the femoral trial PS cam module into
the anterior aspect of the femoral trial box and push
posteriorly until seated (Figure 21b).
Figure 21a
Figure 21b