DePuy LPS™

Transcription

DePuy LPS™

DePuy LPS™
Limb Preservation System
Surgical Techniques
This publication is not intended for distribution in the USA.
DePuy Orthopaedics EMEA is a trading division of DePuy International Limited.
Registered Office: St. Anthony’s Road, Leeds LS11 8DT, England
Registered in England No. 3319712
DePuy Orthopaedics, Inc.
700 Orthopaedic Drive
Warsaw, IN 46581-0988
USA
Tel: +1 (800) 366 8143
Fax: +1 (574) 267 7196
DePuy International Ltd
St Anthony’s Road
Leeds LS11 8DT
England
Tel: +44 (0)113 387 7800
Fax: +44 (0)113 387 7890
www.depuy.com
©DePuy International Ltd. and DePuy Orthopaedics, Inc. 2012.
All rights reserved.
9085-46-000 version 2 Revised: 11/12
CA#DPEM/ORT/1112/0356
0086
DePuy LPS Limb Preservation System
Contents
Significant bone loss requiring extensive reconstruction around the hip and knee is often required following the treatment of
Proximal Femoral Replacement 4
malignant bone tumours, aggressive benign bone tumours, infection, multiple revised and failed joint replacements and massive
trauma, particularly in the elderly osteoporotic patient. Limb-sparing techniques, using modular segmental endoprostheses, provide
Total Femur Replacement 18
Distal Femoral Replacement 26
Proximal Tibial Replacement 38
designed with these considerations in mind to allow for versatility and predictability in such difficult reconstructions.
Mid-shaft Femoral Replacement 48
Other limb-sparing techniques include allograft-prosthetic composites, osteoarticular allografts, intercalary allograft, resection
Appendix I. Implant Taper Disassembly Technique
58
Appendix II: Metaphyseal Sleeves 59
a reliable, functional reconstruction for these patients.
Due to unpredictable and difficult conditions encountered with the remaining bone, muscle and soft tissues, the prosthetic
construct must perform under severe conditions. DePuy Revision Solutions offers both surgeons and patients a comprehensive
portfolio of products for managing the many challenges of total joint arthroplasty. The DePuy LPS (Limb Preservation System) is
arthrodeses, rotationplasties or resection arthroplasties. Each technique has its specific indications, advantages and disadvantages,
and must be chosen based on the individual patient’s functional and psychological needs and the surgeon’s prior experience and
training.
Indications
The DePuy LPS is a modular implant system with a wide choice of components that can be utilised to address severe lower
extremity bone loss secondary to neoplasms, infections, massive trauma or failed joint replacements.
This system is designed to offer:
• Proximal femoral replacement
• Total femur replacement
• Distal femoral replacement
• Proximal tibial replacement
• Mid-shaft femoral (intercalary) replacement
Contraindications
Active sepsis is a contraindication. Treated infection, particularly as a part of a two-stage exchange protocol, with or without an
interim spacer, is not a contraindication. Cautions include marked osteoporosis and metabolic disorders, leading to progressive
deterioration of solid bone support for the implant, distant foci of infections, which may spread to the implant site, and severe
deformities leading to poor fixation or improper positioning of the implant.
2
3
Surgical Technique
Proximal Femoral Replacement
Preoperative Planning
Exposure and Intraoperative Planning
Reconstruction of the proximal femur due to
Perform the surgical approach so that every
significant bone loss can be effectively performed
attempt is made to preserve as much of the
utilising the DePuy LPS. The following technique
abductor mechanism and iliotibial band as
reviews the intended design and use of the
possible while achieving a wide resection of the
instruments and implants for this procedure and
tumour and the biopsy tract in oncology cases.
provides a general framework. Surgeons should
Secure closure of these structures at the end of
utilise techniques that best meet the individual
the procedure is necessary to provide stability
needs of each patient. Consider the following
and improve function. First complete acetabular
recommendations for a successful outcome:
preparation when required, followed by femoral
Steinmann Pin
preparation.
• Perform preoperative planning and
radiographic analysis for every case. Use the
There are many methods to determine resection
DePuy LPS templates (cat. no. 2987-99-000)
length recordings. The following is one method.
in preoperative planning to assess the
Mark points of reference and record between
approximate resection level; position the
the pelvis and an area distal to the appropriate
proximal femoral body replacement and
resection level as determined in preoperative
segmental component(s) (if needed) to restore
planning. After proximal femur and acetabulum
leg length and offset; and determine the
exposure, mark a horizontal line on the femur 1
femoral stem extension diameter and length
cm below the proposed resection level to allow
that could be used to provide adequate
for any slight cut obliquity, blade thickness and
fixation and stability in the remaining host
subsequent femoral resection planing. Make
femoral diaphyseal bone. Although leg length
all marks using an osteotome, electrocautery,
restoration is ideal, in cases where soft-tissues
marking pen or methylene blue.
Distance to
Record
Proposed Level
of Femoral
Resection
Figure.1.1
ƒ: Measure Resect Prox Fem
DePuy Fig 1.1
2/05/03; rev 5/27/03
are resected for oncological purposes,
extremity shortening may be necessary to
Rotational alignment is critical to restoring proper
allow for soft tissue closure around the
anteversion and maintaining hip joint stability. It
prosthesis.
can be determined using several methods.
• Evaluate the acetabulum to decide if
Mark the anterior femoral cortex with a vertical
acetabular reconstruction should be made
line at a site distal to the resection line and
based on the disease process, the degree
perpendicular to the horizontal line previously
of bone loss and the necessity of either an
created. The linea aspera on the femur’s posterior
intra- or extra-articular resection margin in
aspect can act as a guide to the rotational
oncological resections.
orientation of the femur.
An option is to place a Steinmann pin in the
ilium, superior to the acetabular midline. Record
the distance between the Steinmann pin and the
horizontal line on the femur with the leg in a
neutral position with no flexion and record it prior
to any bone resection (Figure.1.1).
4
5
Surgical Technique
Proximal
FemoralBody
Another method at the
Proximal
FemoralBody
beginning
of the
procedure involves performing a secondary
leg length check to verify
the
Segment
almedial malleoli
Component
70 mm
positions of the operative
and non-operative
legs
Stem
Extension
70 mm
90 mm
Stem
Resection
Extension
Level and to ensure
the same relationship following trial
115 mm
implant
insertion.
The
resection level should be
25 mm
20 mm
20 mm Coll
ar
at a level where healthy native diaphyseal bone
is available for stem insertion. If performing the
reconstruction for primary bone sarcoma, review
the preoperative imaging studies, such as plain
radiographs, CT scans and MRI of the femur to
determine a safe resection level.
Figure.1.2
The minimum proximal femoral resection level
is 90 mm from the centre of the femoral head,
Resection
Level
115 mm
20 mm
90 mm
25 mm
Figure.1.3
Next
115 mm
Resection Level
5 mm
Increment
40
45
Next
115 mm
Resection Level
50
5 mm
55
Increment
25 + 25
60
25
35
40
35
40
45
DePuy LPS Segmental Components
25 + 30
25 + 35
65
65
70
25 + 45 or 30 + 40
75
30 + 45 or 35 + 40
80
35 + 45
85
85
90
25 + 65
95
30 + 65
100
35 + 65
115
30 + 85
120
35 + 85
125
125
130
25 + 105 or 45 + 85
25 mm segmental component is the shortest
135
30 + 105
segment available, making 115 mm the next
140
35 + 105
145
40 + 105
150
25 + 125 or 45 + 105
155
30 + 125
Segmental components are then available in 5
160
35 + 125
mm increments alone or in combination with
165
40 + 125
115 mm
otherNext
segmental components
to adjust leg length
170
45 + 125
175
125 + 25 + 25
180
125 + 25 + 30
demonstrate the segmental component lengths
190
125 + 65
available, along with the combination capabilities
195
125 + 25 + 45
to replace missing gaps in 5 mm increments.
200
125 + 35 + 40
205
125 + 35 + 45
210
125 + 85
215
125 + 25 + 65
220
125 + 30 + 65
225
125 + 35 + 65
230
125 + 105
235
125 + 25 + 85
240
125 + 30 + 85
245
125 + 35 + 85
250
125 + 40 + 85
Figure.1.4
6
30
45
femoral replacement body length plus the 20
Increment
Stem
Extension
30
resection level includes the 70 mm proximal
(Figure.1.4). The illustration
and chart to the right
5 mm
Segmental
Component70 mm
90 mm
105
Resection Level
Proximal
FemoralBody
35
65
25
25 +85 or 45 + 65
90 mm
25 mm
30
110
resection level (Figure.1.3).
Stem
Extension
25
85
LPS Segmental Components
105
If additional replacement length is needed, the
Segmental
Component70 mm
Remaining Gap
105
using the +1.5 mm femoral head. This minimum
mm stem component collar height (Figure.1.2).
Proximal
FemoralBody
125
Segmental Stack Chart
7
Surgical Technique
It is recommended that a ring gauge be available.
Resect to healthy femoral diaphyseal bone and
Recording over the stem porous coating and the
1
remove the entire proximal femur, particularly in
final selected reamer will provide the surgeon with
2
oncology cases, so it can be recorded and used
insights based on the actual dimensions of the
3
later as a reference for building the trial construct
implant and reamer.
4
(Figure.1.5).
1
Femoral Resection
Stem Extensions
Cemented Stems (Straight)
Porous Stems (Straight)
Description
Description
10 mm diameter x 100 mm length
11.5 mm diameter x 100 mm length
6
by 0.5 mm for press-fit application using a straight
7
Following femoral resection, prepare the
reamer. If the remaining bone is fragile, consider
line-to-line reaming.
8
remaining femoral canal for the appropriate stem
2
5
When using a straight porous stem, under ream
Femoral Medullary Canal Preparation
3
10
is recommended for the bowed stem extension
When using a bowed porous stem, under reaming
11
and a straight IM reamer is recommended for the
by .5 mm with a flexible reamer for press fit
12
straight stem extension.
application is a technique that can be considered.
4
9
extension. A flexible intramedullary (IM) reamer
5
13
Line-to-line reaming may be indicated, if needed,
to allow the implant to pass through the
15
If using a cemented stem, choose a smaller final
remaining femur’s curvature or if the remaining
16
stem than the last IM reamer used to allow for a
bone is fragile (see Implant Insertion section on
Cemented Stems (Bowed)
Porous Stems (Bowed)
circumferential cement mantle around the stem.
pages 12-14 for additional insight).
Description
Description
Porous Stem Application Options
When using a porous stem, the reaming
6
14
Cemented Stem Application Options
7
For example, if a 15 mm IM reamer was the final
Figure.1.5
reamer used, an 11 mm stem would provide a 2
The DePuy LPS stem extensions are available in
mm cement mantle per side. Using a 12 mm stem
100 and 125 mm straight or 150 and 200 mm
would allow for a 1.5 mm cement mantle per side
bowed lengths in cemented and porous-coated
while a 13 mm stem would have a 1 mm cement
designs (see chart at right).
mantle per side.
Do not ream the femoral canal to cortical
bone for a cemented application. Leave some
cancellous bone for cement interdigitation.
technique utilised will depend on a number of
factors such as the patient age, bone quality,
8
curvature of the remaining femur, etc. The
NOTE: Reference the DePuy LPS
following are general guidelines, as the surgeon
Pocket Reference Guide, Cat.
will need to choose the technique based on
No. 0612-35-050 (Rev. 2), for
individual patient needs.
complete ordering information.
9
Surgical Technique
Finish Preparation Using the
Calcar
Planer
• For a cemented stem extension, begin
Calcar Planer/Bevel Reamer
reaming with a calcar planer/bevel reamer
Once intramedullary reaming is completed,
with a pilot that is at least 1 mm less than the
prepare the osteotomy surface to help assure the
final IM reamer used and finish with a final
stem extension’s proper fit. The calcar planer/bevel
bevel reamer pilot that matches the final
reamer produces an even, perpendicular surface
IM reamer size used. For example, if the last
and is designed to cut an angled relief (bevel) in
IM reamer used was 15 mm, the 15 mm bevel
the bone to match the stem extension flare under
reamer pilot will be the final bevel reamer
the collar. This helps to assure complete femoral
used, irrespective of the stem size chosen, to
stem extension seating on the prepared diaphyseal
allow for an adequate cement mantle.
bone surface (Figure.1.6).
Trial Reduction
Use the calcar planer and insert a bevel reamer
Following femoral preparation for the stem
with a pilot that is at least 1 mm smaller than the
extension, perform a trial reduction. Assemble
last IM reamer used and position it in the femoral
the appropriate proximal femoral body, segmental
canal. Use the appropriate adapter to attach the
component(s) (if needed) and distal stem trial that
assembled planer and bevel reamer with pilot
would fill the missing bone gap based on previous
to a power drill reamer. The calcar planer/bevel
distance estimations. If the proximal femur is
reamer should be under power prior to planing
available in one piece, overlay the trial construct
the resection cut. This will minimise any resected
to assess the replacement for adequate support.
bone chipping caused by the calcar planer cutting
blades.
These recording methods, as previously discussed,
provide a multitude of cross checks when
Figure.1.6
Sequential use of the bevel reamer with pilot will
evaluating the amount of bone to be replaced.
prepare the bevel in the remaining bone with
The trial components are designed to snap
more efficiency and precision. The following are
together and match the implant component
recommendations for calcar planer/bevel reamer
dimensions (Figure.1.7). The trial stem should
use with porous or cemented stems:
closely match the last IM reamer or can be 1 – 2
Figure.1.7
ƒ: Trial Red Prox Fem Rep
DePuy Fig 1.5
2/22/03; rev 4/7/03; 5/27/03
mm smaller depending on the fit.
• For a porous stem extension, begin reaming
with a calcar planer/bevel reamer with a pilot
Utilise the stem trial size to provide enough
that is at least 1 mm less than the final IM
stability to prevent “spinning” when performing
reamer used and finish with a final bevel
a trial reduction. Insert all trial constructs by
reamer that matches the final stem extension
hand and never impact them into the canal.
size. For example, if a 15.5 mm stem is the
The 150 and 200 mm trial stems are bowed and
chosen implant, the final bevel reamer with a
need to be inserted in proper orientation to match
pilot will be the 15.5 mm.
the femur’s anterior bow. Insert the trial construct
Figure.1.8
into the remaining proximal femur and use it to
Note that the pilot is undersized by 0.5 mm
assess fit, leg length, offset, joint stability, soft
from the stated size. For example a 15.5 mm
tissue tension and range of motion (Figure.1.8).
ƒ: Trial Red Prox Fem Rep
DePuy Fig 1.5
2/22/03; rev 4/7/03; 5/27/03
pilot is 15 mm in diameter.
• This makes allowances for an under ream
technique. If a 15 mm IM reamer was last
used, the final bevel reamer with a pilot will
still be 15.5 mm to match the implant.
10
11
Surgical Technique
If the soft tissues are tight, the leg length is
If a bowed stem is used, the surgeon has much
slightly long and the implant’s offset is excessive,
less control over the stem’s rotation within the
evaluate the use of a shorter femoral head trial.
femur. This situation is where the anteverted
If the soft tissues are tight and the leg length
15-degree proximal femoral body should be
is long, but the femoral offset is acceptable,
considered.
Impaction
Cap
try reducing the vertical height/leg length by
adjusting the segmental trials.
Implant Assembly
Once the trial segments have yielded a satisfactory
If the segmental trials used are at the minimum
result with the trial reduction, assemble the
length of 25 mm and the leg length is long,
appropriate implant components using the
consider recutting the femoral osteotomy to
implant impaction stand. This helps to stabilise the
adjust for the leg length discrepancy. If the
implant components for assembly and impaction.
Stem
Extension
femoral cut is revised, re-ream the femur distally
Alignmen
Mark
and finish the prepared surface with the calcar
It is important to orient the implant components
planer/bevel reamer. If this is not done, the
along the same axis as the trial components,
stem’s distal end may encounter unreamed bone
particularly when using a bowed stem. The
and an intraoperative fracture may occur. If the
implant components use a Morse-taper design
soft tissues are loose and the femoral offset is
for locking. Assemble the components by hand
inadequate, try a longer femoral head trial.
and place the impaction cap over the stem
Segmental
Component
Proximal
Femoral
Body
Femoral
Impaction
Stand
component. Then impact them together using
Be aware that the ability to judge soft tissue
a mallet to securely seat the tapers together
tension is compromised when the abductor
(Figure.1.10). There should be approximately a
musculature attachment has not yet been
1 mm gap between the component bodies after
reconstructed. One test for excessive soft tissue
impaction.
tension is to extend the hip and try flexing the
knee. If the hip flexes when the knee flexes, the
soft tissue tension may be excessive.
At this point, another way to intraoperatively
Figure.1.9
Impaction
Cap
Impaction
Cap
Stem
Extension
Stem
Extension
Segmental
Component
Segmental
Component
Proximal
Femoral
Body
Proximal
Femoral
Body
check leg length recording is to compare the
medial malleoli. Use the trial construct to assess
proper femoral anteversion. This is not difficult if a
straight stem is used. In this case, use the neutral
femoral body and rotate the entire construct
within the femur to obtain the required femoral
anteversion (usually 10 – 15 degrees).
Once proper anteversion orientation is established,
use the anti-rotation slot (tab) on the trial as a
reference to mark the femur (Figure.1.9). This
final mark will serve as an alignment guide when
inserting the implant.
Femoral
Impaction
Stand
Femoral
Impaction
Stand
Figure.1.10
12
13
Surgical Technique
Implant Insertion
When using a bowed porous stem, curvature of
If using SMARTSET® MV bone cement to fix the
the remaining bone in comparison to the implant
distal femoral stem extension to host bone, follow
needs to be appraised especially for the impact of
the manufacturer’s recommended procedures to
mismatch conditions. Under reaming by 0.5 mm
mix, deliver and pressurise the bone cement.
with a flexible reamer is a technique that can be
considered. Insertional feel and non-advancement
Versio
Guide
Use the DePuy LPS inserter/extractor with the
with component impaction should be an
version guide and with the implant construct
indication to remove the construct and try to
to assist in the insertion of the implant into
pass the same flexible reamer another four to six
the femoral canal. Thread the inserter into
times and evaluate the insertional feel again. If
the proximal femoral body and place the
the construct still presents with non-advancement,
version guide around the neck of the implant
line-to-line reaming should be considered. The
(Figure.1.11). Make certain that the inserter
construct should then be inserted into the
threads are completely seated and that no threads
medullary canal and attention to insertional feel
are showing.
and advancement assessed again.
To determine the implant’s proper orientation,
Placement of a “prophylactic” cerclage wire
use the alignment mark previously placed on
around the proximal end of the remaining
the femur and the implant’s anti-rotation slot
diaphysis may decrease the risk of intraoperative
(tab) (Figure.1.12 see page 15). Note that the
fracture during press-fit insertion of the porous
150 and 200 mm stems are bowed and the
stem extension, particularly with fragile bone.
Alignm ent
Mark
correct bow-to-femur orientation must be
accomplished.
Figure.1.12
Should the implant construct with a porous stem
not advance and become lodged in the femoral
If cement is used, remove any excess cement from
canal, there are two methods for removal. First,
around the implant collar during insertion and
try to remove the implant by using the mallet to
after final seating.
strike the platform of the inserter to extract the
construct. If this fails, disassemble the implant
Figure.1.11
The stem extension shoulder should be flush to
construct from the stem extension using the
the femur’s cut surface (Figure1.13 see page 15).
disassembly tool (see disassembly technique
Give meticulous attention to the stem position.
on page 56 – 57). The exposed porous stem
Failure to align the stem in proper version may
extension taper is threaded. Remove the version
result in instability.
guide from the inserter/extractor. Place the slap
Complet
Seatin
handle through the inserter/extractor. Completely
thread the inserter/extractor into the porous
stem thread. Use the slap handle to provide
the extraction force to the lodged porous stem
extension until it is removed from the femoral
canal. An DePuy LPS extension adapter (Cat. No.
2987-72-045) is also available for use with the
slap hammer and rod from the Moreland Hip
Revision Instrument Set when additional force is
required. Evaluate the need to re-ream the canal.
Reassemble the components making sure the
Figure.1.13
tapers are clean and dry before assembly.
Reinsert the implant construct.
ƒ: Prox Fem Complete Seated
DePuy Fig 1.10
4/7/03; rev 5/27/03
14
15
Surgical Technique
Steinmann P
Perform a final trial reduction with the implant to
If the abductors are extensively shortened,
fine tune soft tissue balancing. Make alterations
use the proximal femoral replacement body
using either longer or shorter trial femoral heads
with trochanteric build-up for reattachment
as needed. Check leg length restoration against
(Figure.1.16). Abductor function is significantly
the initial reconstruction distance recordings
enhanced if at the time of initial resection the
(Figure.1.14).
abductors and vastus lateralis are taken together
in one layer and the abductors are not detached.
Reconstruct
Distance
Closure
Do this whenever possible from the oncological
Soft tissue reconstruction is one of the most
point of view. This is very similar to the
important aspects of this procedure. Restoration
trochanteric slide or vastus slide approaches used
of the abductor musculature attachment is
in revision total hip arthroplasty.
important for postoperative hip stability and gait.
The proximal femoral replacement segment holes
Twist the selected femoral head implant onto the
allow for soft tissue reattachment using sutures or
implant neck taper and then impact it with a head
MERSILENE tape (Figure.1.15), but the long-term
impactor and mallet using a sharp blow. Use the
stability of soft tissues using this method is
acetabular component (i.e., bipolar cup, fixed cup,
uncertain. Another method is to use the suture
cage, etc.) based on the specific patient’s needs.
®
Figure.1.16
holes to assist in securing a tenodesis between the
abductor tendons and the adjacent iliotibial band.
Complete the operation with a multi-layer soft
tissue closure over drains. Meticulous closure
Use the proximal femoral body replacement
is important to minimise the possibility of
component to reattach the greater trochanter,
postoperative hematoma formation, which is
when present (Figure.1.15). This feature works
possible with a large dissection. Use the standard
by utilising the reattachment holes provided in
closure over drains and soft tissue reattachment
the proximal femoral body component. Attach
procedures.
the greater trochanter and abductors with either
heavy sutures or MERSILENE tape.
Postoperative Care
Individualise postoperative care, as many
of these procedures involve extensive
Figure.1.14
dissections.
The patient’s activity and weight-bearing
status will depend on the extent of the
surgery, the individual patient’s needs and the
implant’s fixation type. The weight-bearing
status is generally full weight bearing with
cemented stems. With cementless stems,
individualise the weight-bearing status based
on patient’s needs. However, it is suggested
for patients not on chemotherapy to adhere
to toe-touch weight bearing for at least six
weeks. For patients on chemotherapy, 12
weeks is suggested.
Figure.1.15
16
17
Surgical Technique
Total Femur Replacement
The DePuy LPS can be used to replace the entire
Use the surgical approach based upon the
femur. The following technique reviews the
surgeon’s preoperative plan and exposure
intended design and use of the instruments and
preference. During the reconstruction, take
implants for this procedure and provides a general
care to avoid stretch injury to the neurovascular
framework. Utilise techniques that best meet
structures in this extensive procedure. Perform the
the needs of each case, since each is unique and
acetabular reconstruction as required.
has specific challenges. Consider the following
If using a fixed acetabular component, consider
70 mm
25 mm
25 mm
350 mm
Rem aining
Gap
175 mm
125 mm
using a large femoral head (>32 mm), a
• Using preoperative templating, use the full
lower extremity radiographs to help determine
Segm ental
Com ponents
55 mm
constrained liner or a tripolar construct for
stability.
the length of femur to be replaced by the
prosthesis and if there are any special needs
Leg length recordings are very important for a
in reconstructing the acetabulum and
successful surgical outcome. An example of one
proximal tibia.
recording method utilises a horizontal line made 1
50 mm
cm below the proposed tibial resection level using
• The minimum DePuy LPS total femoral
construct when using the X-small LPS distal
XX-sm all
an osteotome, electrocautery, marking pen or
methylene blue.
femoral component is 185 mm, which
70 mm
includes the proximal femoral body (70
Place a Steinmann pin in the ilium, superior
mm), total segmental (55 mm) and distal
to the acetabulum midline. Extend the limb
femoral (60 mm) components. The minimum
and record the distance between the pin and
LPS total femoral construct when using the
marked horizontal line on the tibia and record
xx-small distal femoral component is 175 mm,
the length prior to any resection (Figure.2.2). It
which includes the proximal femoral body
is important to record the knee in full extension.
(70 mm), total segmental component (55 mm)
Avoid distance estimation with the knee in flexion
and distal femoral (50 mm) component. Use
for consistency of recording results. Remove the
additional segmental components to replace
Steinmann pin and mark the hole with a cautery
missing femoral bone (Figure.2.1).
or marker pen so the Steinmann pin location
ƒ: Replace Femur 50Sm
DePuy Fig 2.1 Revised Steinmann
2/17/03; 10/16/04; 1/26/05 (50mm)
P
can be found and reinserted later during the trial
55 mm
Segmental
Components
reduction process.
Resecti
on
Length
Excise the femur according to standard
40 mm
oncological principles for a neoplasm or as
350 mm
dictated by the underlying pathology, such as post
Remaining Gap
165 mm
infection, end-stage revision arthroplasty, etc.
125 mm
10 mm Below
Proposed
TibialResecti
on
60 mm
X-small
Figure.2.1
Figure.2.2
18
19
Surgical Technique
Fem oralProxim al
Body Replacem ent
Trial
TotalSegm ental
Trial
Tibial Preparation
Insert the Steinmann pin into the previously
Prepare the proximal tibia. This can be done with
drilled hole in the ilium. Check the femur’s length
intra-medullary or extramedullary instrumentation
against the recordings prior to the resection.
that is available with the Mobile Bearing Tibial
Make femoral length changes by changing
(M.B.T.) revision knee system. The remainder of
the segmental trial lengths, which offer 5 mm
the tibial preparation follows the technique for
increment capability. Compare the knee joint
the M.B.T. Revision Tibial Tray or available in the
line to the opposite side for proper height.
SIGMA® Revision and M.B.T. Revision Tray Surgical
The joint line is determined by the level of
Technique, cat. no. 0612-51-506.
femoral component. Assess proper anteversion
Antevers
(Figure.2.5), offset and stability.
Segm ental
Trial
When using the M.B.T. revision tibial tray, only
Segm ental
Trial
use the DePuy Universal LPS hinged tibial insert
Make fine adjustments to leg length and femoral
bearing. Use only the Universal LPS hinged tibial
offset using the range of different femoral head
insert bearing sizes that match the size of the
lengths. Use varying tibial insert polyethylene
DePuy LPS Distal Femoral Replacement component
heights to provide joint stability and to adjust leg
being used.
length.
Figure.2.5
ƒ: Antevers Total Fem
DePuy Fig 2.5
2/23/03; rev 5/27/03
Resurface the patella using the SIGMA dome
patella component.
Trial Reduction
DistalFem oral
Replacem ent
Trial
Assemble the total femur trial components for
an initial trial reduction to check for the correct
approximation of the femoral replacement. The
Figure.2.3
trial construct consists of a proximal femoral body,
total segmental, segmental and distal replacement
trial components (Figure.2.3).
Perform trial reduction after assembling the
DePuy LPS proximal femur trial and tibial trial
components (Figure.2.4). Use the proximal femoral
body trial with 15 degree built-in anteversion to
evaluate the proper total femoral replacement
version.
Hinge Pin T
Figure.2.4
20
21
Surgical Technique
Impaction
Cap
Implant Assembly
Once the final trial reduction is accomplished,
After trial reduction, assemble the implants using
connect the total femur construct to the DePuy
the implant holder stand on the back table. The
LPS hinged tibial insert bearing using the locking
implant component alignment should duplicate
pin, which is passed through the DePuy LPS distal
the trial component’s orientation so that femoral
femoral replacement component and the bushings
anteversion and proper femoral/tibial construct
of the hinged tibial insert bearing (Figure.2.7).
alignment is correct. Place the distal femoral
Proximal
FemoralBody
Segm enta
l
Components
replacement component on the distal femoral
Note: The locking pin can be inserted from
impaction stand.
either the medial or lateral sides.
Stack the component tapers to assemble the
One method that can be used to secure the
total femoral and segmental components and the
locking pin uses manual pressure to push the
proximal femoral body replacement component.
locking pin through until it “clicks” and locks into
Use the impaction cap to impact down on the
place.
proximal femoral replacement body to impact
Tota
lF
emoral
Segm enta
l
Component
the tapers together (Figure.2.6). There should
Another method uses forceps to squeeze the
be approximately a 1 mm gap between the
locking pin while pushing the pin until it is
component bodies after impaction.
completely seated in the square cut-out in the
DePuy LPS distal femoral component. Pressure is
Distal F
emoral
Component
Implant Insertion
released from the forceps. Once the pin is securely
If using SMARTSET MV bone cement, mix
locked, push the locking pin from the opposite
and deliver according to the manufacturer’s
side of insertion and confirm that it is captured
recommendation. Impact and hold the tibial tray
and locked.
Hinge Pin
component until the cement is cured. Only apply
cement to the prepared tibia surface.
Femoral
Impaction
Stan
d
Place the total femur implant construct into the
remaining femoral soft tissue envelope. Reduce
the DePuy LPS femoral replacement into the
Figure.2.6
Figure.2.7
chosen acetabular and tibial components. Trial
femoral heads and trial tibial inserts can be
evaluated to make assessments in choosing final
ƒ: Total Fem/MBT Tib
DePuy Fig 2.7
2/22/03; rev 4/7/03; rev 5/27/03 rev 10/1/03
implant sizes.
22
23
Surgical Technique
Steinmann
Once the total prosthesis is positioned in vivo,
Suture the iliopsoas muscle, if desired, to the
perform the final leg length and offset checks
holes in the medial aspect of the proximal femoral
with a trial femoral head (Figure.2.8). Remove
body replacement component. Reattach the
the trial femoral head, twist the selected femoral
vastus lateralis to the intermuscular septum, the
head into the proximal femoral body taper and
fascia lata and knee joint capsule, if present.
impact it with a mallet blow. Reduce the DePuy
The rotating knee hinge allows for 6 degrees of
LPS femoral replacement into the acetabular
hyperextension to 110 degrees of flexion.
component.
If, due to grossly inadequate soft-tissue integrity,
Resecti
on
Length
Check
Closure
knee flexion beyond 90 degrees causes luxation
With the components securely in place, soft
of the hinged insert bearing out of the tibial
tissue closure is important to successful procedure
component base, the patient must have a
completion. If the hip capsule is present, place a
knee brace postoperatively to limit flexion to
purse-string suture around the residual capsule
90 degrees. In such cases, consider closing the
and secure it over the bipolar or acetabular
wound with the knee in full extension. Close
component chosen.
the knee joint and skin in layers after inserting a
suction drain.
Use the proximal femoral body replacement
component to reattach the greater trochanter
when present. This feature works by utilising
the reattachment holes provided in the proximal
Postoperative Care
femoral body component. Attach the greater
trochanter and abductor with either a heavy
Individualise postoperative care.
suture or MERSILENE tape. If the abductors are
extensively shortened, use the proximal femoral
These procedures involve extensive dissections
replacement body with the trochanteric build-up
with the placement of large drains.
for reattachment.
Weight-bearing protocol depends on the
Figure.2.8
If possible, suture the gluteus medius muscle to
acetabular reconstruction and soft tissue
the lateral femoral muscles and then fasten the
stability.
fascia lata to the proximal femoral replacement
component holes. This assists in securing the
gluteus musculature until scar tissue is formed
with the surrounding soft tissue protecting against
early subluxation.
24
25
Surgical Technique
Distal Femoral Replacement
Exposure
Use the DePuy LPS to efficiently perform distal
Use a surgical approach that best achieves the
femur reconstruction due to significant bone loss.
exposure needed for extensive removal of bone
The following technique reviews the intended
in the distal femur and proximal tibial areas. Leg
X-small
X-small
distal femur
design and use of the instruments and implants
Additional
5 mm Increments
Next Resection Level
105 mm
length recording and alignment are important
20 mm
for this procedure and provides a general
checks to be done prior to any bone resection.
framework. Utilise techniques that best meet the
During surgery, take care to avoid stretch injury
needs of each case, since each case is unique and
to the neurovascular structures. If performing
with its own challenges. Consider the following
the reconstruction for primary bone sarcoma,
80 mm
60 mm
X-smallimaging studies, such as plain
the preoperative
be reviewed to determine a safe resection level.
X-small
distal femur
radiographs, CT scans and MRI of the femur, must
Additional
5 mm Increments
105 mm
DePuy LPS templates for preoperative planning
Intraoperative Planning 20 mm
femur
position of the distaldistal
femoral
replacement and
Additional
80 mm when using the X-small distal femoral5 mm
Increments
replacement component with DePuy LPS stems.
The minimum X-small
distal femoral resection level is
X-small
to assess the approximate
resection level;
the joint line; and determine the diameter
The minimum
distal femoral resection105
is 70
mm
XX-small
mm whendistal
usingfemur
the XX-small distal femoral
and length of the femoral stem extension
that
20 mm
could be used to provide adequate fixation
diaphyseal bone.
(Figure.3.1 see page 26).
X-small
XX-small
distal femur
20 mm
Next Resection
Level
105 mm
segment available, making the
65 mm
Minimum
Resection
60Level
mm
20 mm
20 mm
XX-small
105 mm
Missing
Gap =mm
105
65 mm
Additional
5 mm Increments 145 mm
60 mm
95 mm
145 mm
components are then available in 5 mm
60 mm
increments
XX-small
distal femur
80 mm
20 mm
alone or in combination
with other
XX-small
(Figure.3.3). The chart on page 29
Additional
demonstrates
5 mm Increments
20 mm
the segmental component lengths available along
95
mm
with the combination capabilities to replace
Minimum
Additional
5 mm Increments
Figure.3.1
50 mm
35 mm
95 mm
Minimum
Resection20Level
mm
70 mm
50 mm
20 mm
Missing
Gap
75 mm
40 mm
35 mm
50 mm
Additional
5 mm Increments
20 mm
Missing
Gap =
75 mm95 mm
Minimum
145 mm
Resection Level
Missing
Gap
75 mm
40 mm
35 mm
50 mm
70 mm70 mm
Figure.3.3
26
80 mm
Minimum
Resection Level
Missing
Gap =
75 mm
145 mm
70 mm
XX-small
XX-small
distal femur
20 mm
40 mm
50 mm
70 mm
50 mm
XX-small
Missing
Gap
75 mm
Resection Level
missing gaps in 5 mm increments.
20 mm
70 mm
segmental components to adjust leg length
50 mm
Missing
Gap
75 mm
Missing
Gap =
65 mm
65 mm
the
80 mm
next resection level (Figure.3.2). Segmental
80 mm
Minimum
Resection Level
Figure.3.2
70 mm
Minimum
The 25
mm segmental component is the shortest
20 mm
Resection Level
5 mm Increments
the tibia.
80 mm
95 mm
Additional replacement length is often needed.
choose the implant system used toAdditional
reconstruct
XX-small
distal femur
65 mm
60 mm
Additional
5 mm Increments
50 mm
Missing
Gap =
65 mm
Additional
145 mm
5 mm Increments
20 mm collar height
plus the 20 mm
stem component
X-small
or abnormalities that may be present and to
60 mm
XX-small
Minimum
Resection Level
component lengths of 50 mm and 60 mm
X-small
• Evaluate the tibia to
assess
any deficiencies
distal
femur
X-small
distal femur
20 mm
replacement component. This minimum80 resection
mm
level includes the distal femoral replacement
60 mm
and stability in the remaining host femoral
Minimum
Resection Level
80 mm
60 mm
segmental component(s) (if needed) to restore
Minimum
Resection Level
27
Missing
Gap =
75 mm
145 mm
70 mm
Missing
Gap
75 mm
Surgical Technique
125
105
85
65
Proposed Level
of Femoral
Resection
After achieving distal femur and proximal tibia
Distal Femoral Resection
exposure, mark the proposed distal femoral
When a distal femoral tumour resection is
resection level with the extremity fully extended in
required, excise the tumour and affected soft
a reproducible position. Avoid distance estimates
tissue prior to any tibial bone resection, except
with the knee in flexion for consistency of
in the case of an extra-articular resection. In
recording results. Make a horizontal line on the
this case, it is technically easier to osteotomise
femur 1 cm above the proposed resection level as
or resect the patella first, then cut the tibia and
a reference for use in leg length recordings. Then
finally cut the femur. Once the bone and soft
mark a perpendicular vertical line on the anterior
tissue resection have been performed, prepare the
cortex midline in line with the femoral trochlear
remaining host femur.
25
Remaining Gap
LPS Segmental Components
25
25
30
30
femoral prosthesis rotational alignment.
35
35
40
40
45
45
50
25 + 25
Make another horizontal line 1 cm below the
remaining femoral canal for the appropriate stem
proposed resection level on the tibia for use as a
extension. A flexible IM reamer is recommended
55
25 + 30
reference in leg length estimation. These marks
for the bowed stem extension and a straight IM
60
25 + 35
can be made with electrocautery, osteotome,
reamer is recommended for the straight stem
marking pen or methylene blue (Figure.3.4).
extension.
65
65
70
25 + 45 or 30 + 40
75
30 + 45 or 35 + 40
80
35 + 45
85
85
If using a cemented stem, choose a final stem that
90
25 + 65
Another recording that is useful is the distance
is smaller than the last reamer used to allow for a
95
30 + 65
100
35 + 65
from the natural joint line to the horizontal
105
105
line marked on the femur. This is a very useful
For example, if a 15 mm IM reamer was last used,
110
25 +85 or 45 + 65
reference when re-establishing the level of the
an 11 mm stem would have a 2 mm cement
115
30 + 85
joint line.
mantle per side.
120
35 + 85
125
125
130
25 + 105 or 45 + 85
Do not ream the femoral canal to cortical
135
30 + 105
Prepare the proximal tibia. This can be done with
140
35 + 105
intramedullary or extramedullary instrumentation
Tibial Preparation
that is available with the M.B.T. revision knee
system.
145
40 + 105
150
25 + 125 or 45 + 105
155
30 + 125
160
35 + 125
When using a porous stem, the reaming
165
40 + 125
170
45 + 125
175
125 + 25 + 25
180
125 + 25 + 30
When using the M.B.T. revision tibial tray,
technique utilised will depend on a number of
only use the Universal DePuy LPS hinged tibial
factors such as the patient age, bone quality,
insert bearing. Use only the DePuy LPS hinged
curvature of the remaining femur, etc. The
190
125 + 65
tibial insert bearing size that matches the size
following are general guidelines, as the surgeon
195
125 + 25 + 45
of the DePuy LPS Distal Femoral Replacement
will need to choose the technique based on
200
125 + 35 + 40
component being used.
individual patient needs. It is recommended that a
205
125 + 35 + 45
210
125 + 85
ring gauge be available. Distance estimation over
215
125 + 25 + 65
the stem porous coating and a recording of the
220
125 + 30 + 65
final selected reamer will provide the surgeon with
225
125 + 35 + 65
insights based on the actual dimensions of the
implant and reamer.
28
45
groove. This mark serves as a reference for correct
resection and use for future reference in the case.
Figure.3.4
40
Segmental Stack Chart
Record this distance estimation prior to any
Proposed Level
of Tibia
Resection
35
DePuy LPS Segmental Components
Following femoral resection, prepare the
Distance
Record
30
29
230
125 + 105
235
125 + 25 + 85
240
125 + 30 + 85
245
125 + 35 + 85
250
125 + 40 + 85
Surgical Technique
When using a straight porous stem, under ream
The calcar planer/bevel reamer should be under
Stem Extensions
by 0.5 mm for press-fit application using a straight
power prior to planing the resection cut. This
reamer. If the remaining bone is fragile, consider
will minimise any resected bone chipping by the
Description
Description
line-to-line reaming.
calcar planer cutting blades. The following are
recommendations for the calcar planer/bevel
When using a bowed porous stem, under reaming
reamer for use with cemented or porous stems:
by 0.5 mm with a flexible reamer for press fit
application is a technique that can be considered.
Line-to-line reaming may be indicated if needed to
with a calcar planer/bevel reamer with pilot
allow the implant to pass through the remaining
femur’s curvature or if the remaining bone is
fragile (see Implant Insertion section on pages
32-34 for additional insight).
chosen implant, the final bevel reamer with
Description
Description
a pilot will be the 15.5 mm. Note: the pilot is
100 and 125 mm straight or 150 and 200 mm
undersized by 0.5 mm from the stated size.
bowed lengths in cemented and porous-coated
For example a 15.5 mm pilot is 15 mm in
styles (see chart on page 29).
diameter. This makes allowances for an under
ream technique. If a 15 mm IM reamer was
Finish Preparation Using the Calcar Planer/
last used, the final bevel reamer with a pilot
Bevel Reamer
will still be 15.5 mm to match the implant.
Once reaming is completed, prepare the
osteotomy surface to help assure the stem’s
• For a cemented stem extension, begin reaming
proper fit. The calcar planer/bevel reamer
produces an even cut surface and an angled relief
(bevel) in the bone to match the stem extension
flare under the collar. This helps to ensure
reamer pilot that matches the final IM reamer
complete stem extension seating on the prepared
size. For example, if the last IM reamer used
diaphyseal bone surface.
was 15 mm, the 15 mm bevel reamer pilot will
Figure.3.5
be the final bevel reamer used irrespective of
Use a calcar planer and insert a bevel reamer with
the stem size chosen to allow for an adequate
a pilot that is at least 1 mm smaller than the last
cement mantle.
IM reamer used (Figure.3.5) and insert it into the
femoral canal. Sequential use of the bevel reamer
with the pilots prepares the bevel in the remaining
• Resurface the patella using the SIGMA dome
patella component.
bone with more efficiency and precision. Attach
the assembled planer and bevel reamer with a
Trial Reduction
pilot to a power drill reamer using the appropriate
Following the femur’s preparation for the stem
No. 0612-35-050 (Rev. 2), for
adapter.
extension, perform a trial reduction. Replace the
missing bone from the distal femoral resection
to the expected joint line level. Utilising this
recording, assemble the appropriate distal femoral
replacement component, segmental component(s)
and distal femoral stem trials that would fill the
missing bone gap (see chart on page 27).
30
31
Surgical Technique
If the distal femur is available in one piece, an
The 150 and 200 mm trial stems are bowed and
alternate method is to record the resected bone
need to be inserted in proper orientation to match
from the osteotomy to the end of the condyles.
the femur’s anterior bow. Insert the trial construct
Then assemble the trial components and from the
into the remaining distal femur and use it to
joint line to the resection line, evaluate the match
assess fit, leg length, joint line, joint stability, soft
of the trial to the resected bone (Figure.3.6). The
tissue tension and range of motion (Figure.3.8).
trial components are designed to snap together
If the soft tissues are tight and are adversely
1
(Figure.3.7 see page 33). Utilise the stem trial size
affecting the range of motion, consider soft tissue
2
to provide enough stability to prevent “spinning”
releases. However, if the leg has been excessively
when performing a trial reduction.
lengthened, reducing leg length will correct the
1
and match the implant component dimensions
3
4
problem. The leg length can be adjusted with
the segmental trials, which allows for 5 mm
6
IM reamer used or it can be 1 – 2 mm smaller
increments of correction.
7
depending on fit. Insert trial constructs by
2
5
The trial stem should closely match the last
3
8
9
hand. Never impact them into the canal.
Compare the knee joint line to the opposite side
4
10
for proper height. The joint line is determined
11
by the level of the femoral component. If the
12
segmental trials used are at the minimum length
14
consider recutting the femoral osteotomy to
15
adjust for the discrepancy. If the femoral cut is
6
13
5
of 25 mm and the joint line is too far distal,
16
Figure.3.6
Alignmen
Mark
revised, re-ream the femur more proximally and
7
finish the osteotomised surface with a calcar
planer/bevel reamer. The stem’s distal end may
encounter unreamed bone and an intraoperative
fracture may occur if re-reaming is not done.
Figure.3.7
Varying the hinged tibial insert trial heights
can affect leg length. Use the trial construct to
Figure.3.8
assess proper component rotational orientation.
Once proper orientation is established, use the
anti-rotation slot (tab) on the trial as a reference
to mark the femur. This mark serves as an
alignment guide when inserting the final implant
(Figure.3.8).
32
33
Surgical Technique
Impaction
Cap
Stem
Extension
Implant Assembly
Under reaming by 0.5 mm with a flexible reamer
Once the trial segments yield a satisfactory result
is a technique that can be considered. Insertional
with the trial reduction, assemble the appropriate
feel and non-advancement with component
implant components. Use the implant impacting
impaction should be an indication to remove
stand to help stabilise the implant components for
the construct and try to pass the same flexible
assembly and impaction. It is important to orient
reamer another four to six times and evaluate the
the implant components along the same axis as
insertional feel again. If the construct still presents
the trial components. The implant components
with non-advancement, line-to-line reaming
use a Morse-taper design for locking. Assemble
should be considered. The construct should then
the implant components by hand and place the
be inserted into the medullary canal and attention
impaction cap over the stem component. Then
to insertional feel and advancement assessed
impact the components together using a mallet
again.
Alignmen
Mark
to securely seat the tapers together (Figure.3.9).
There should be approximately a 1 mm gap
Placement of a “prophylactic” cerclage wire
between the component bodies.
around the proximal end of the remaining
diaphysis may decrease the risk of intraoperative
Segm enta
l
Component
Implant Insertion
fracture during press-fit insertion of a porous stem
If using SMARTSET MV bone cement to fix the
extension particularly with fragile bone.
Should the implant construct with a porous
stem not advance and become lodged in the
femoral canal, there is a technique for removal.
Distal
Femoral
Component
Femoral
Impaction
Stan
d
Use the distal femoral impactor with the
Disassemble the implant construct from the
implant construct to assist in the insertion of
stem extension using the disassembly tool (see
the implant into the femoral canal. The distal
disassembly technique on page 58). The exposed
femoral impactor mates with the distal femoral
porous stem extension taper is threaded. Place
replacement component. Use a mallet to impact
the slap handle through the inserter/extractor.
the assembled construct (Figure.3.10 see page
Completely thread the inserter/extractor into
35).
the porous stem thread. Use the slap handle to
Figure.3.10
ƒ: Impact Distal Fem
DePuy Fig 3.7
2/17/03; 4/7/03; 5/27/03
provide the extraction force to the lodged porous
Figure.3.9
Use the alignment mark previously placed on
stem extension until it is removed from the femur.
the femur and the implant’s anti-rotation slot for
Make sure the tapers are clean and dry before
proper implant orientation. Note that the 150
assembly. Reinsert the implant construct after
and 200 mm stems are bowed and the correct
re-reaming.
Complet
Seatin
bow-to-femur orientation must be accomplished.
The stem extension shoulder should be flush to
If using the porous stem, impact the construct
the femur’s cut surface when using either the
in place using a mallet to strike the inserter and
cemented or porous stem extension (Figure.3.11).
align the anti-rotation tab with a mark on the
Give meticulous attention to the distal femoral
femur for proper alignment (Figure.3.11 see page
component’s rotation. If it is internally rotated,
35). Insert a cemented stem and align as noted
patellar instability will result.
above. Remove excess bone cement from around
the implant collar.
Perform a final trial reduction. Evaluate stability
and leg length adjustments by using the
When using a bowed porous stem, curvature of
trial-hinged tibial-bearing trials prior to choosing
the remaining bone in comparison to the implant
the final implant component.
needs to be appraised especially for the impact of
Figure.3.11
mismatch conditions.
34
35
ƒ: Flush Seat Distal Fem
DePuy Fig 3.8
3/29/03; rev 5/27/03
Surgical Technique
Use the locking pin to mate the distal femur
Perform wound closure in multiple layers
component to the tibial bearing through the
to minimise hematoma formation. Perform
hinged tibial insert bearing. Pass the locking pin
meticulous wound closure to minimise wound
through the DePuy LPS distal femoral replacement
complications that may preclude immediate
component and the hinged tibial insert-bearing
physical therapy or other adjuvant oncological
bushings (Figure.3.12 and 3.13).
treatments, such as radiation therapy or
chemotherapy.
One method to secure the locking pin uses
manual pressure to push the locking pin through
Occasionally, if there is significant soft tissue
until it “clicks” and locks into place. Another
fibrosis (e.g. from prior surgery, trauma,
method uses forceps to squeeze the locking
irradiation, etc.), then extremity shortening may
pin while pushing the pin until it is completely
be necessary to minimise soft tissue tension and
seated in the square cut-out in the DePuy LPS
allow wound closure without undue tension.
distal femoral component. Once the pin is seated,
Typically the wound is closed over large bore
release the pressure from the forceps. Once the
drains to minimise hematoma collection.
pin is securely locked, push the lock pin from the
opposite side of insertion and confirm that it is
captured and locked.
Postoperative Care
Closure
1
2
If knee flexion beyond 90 degrees causes luxation
Individualise postoperative care. Many of
of the hinged insert bearing out of the base
these procedures involve extensive dissections.
of the tibial component, this could be due to
The patient’s activity and weight-bearing
grossly inadequate soft tissue integrity. In that
status will depend on the extent of the
situation, the patient must have a knee brace
surgery, the individual patient’s needs and
postoperatively to limit flexion to 90 degrees.
the implant’s fixation type.
In such cases, consider closing the wound with
Figure.3.12
ƒ: Distal Fem/MBT Tib
DePuy Fig 3.9
2/24/03; 3/29/03; 5/27/03
the knee in full extension. One of the most
The weight-bearing status with cemented
important aspects of this procedure is the soft
stems is generally full. With cementless
tissue reconstruction, which is done based on
stems, the weight-bearing status can be
individual patient needs. Soft tissue closure should
individualised based on the patient’s needs.
completely cover the prosthesis.
However, it is suggested for patients not on
Figure.3.13
ƒ: Meas
LPS Distal Fem
2/25/03; rev 4/7/03; rev 10/1/03
chemotherapy to adhere to toe-touch weight
In oncological applications when soft tissues are
bearing for eight weeks. For patients on
resected to achieve a wide bone tumour margin,
chemotherapy, 12 weeks is suggested.
the amount of remaining soft tissue coverage
is reduced. In this case, remaining musculature
mobilisation may be necessary to achieve proper
soft tissue coverage around the prosthesis.
36
37
Surgical Technique
Proximal Tibial Replacement
Universal LPS Hinged
Tibial Insert Bearing
Proximal
Tibia
l
Replacemen
t
Componen
tPlanning
Preoperative
12 m
105 mm
Proximal
Tibia
l
Replacemen
t
t
Exposure andComponen
Intraoperative
Planning
Use a surgical approach that best achieves the
proximal tibia reconstruction due to significant
exposure needed for extensive bone removal in
73femoral
m
the proximal tibial and distal
areas. It
73 m bone loss. The following technique reviews the
20 m
12 m
Use the DePuy LPS to efficiently perform the
intended design and use of the instruments and
is important to check leg length recording and
implants for this procedure and provides a general
alignment prior to any bone resection. During
framework. Utilise techniques that best meet
surgery, take care to avoid stretch injury to
the needs of each case, since each is unique and
20 m If performing the
the neurovascular structures.
105 mm
130 mm
25 m
130 mm
Segmenta
l
reconstruction for primary bone sarcoma,
review
Componen
t
has specific challenges. Consider the following
Minimum
Resection Lev
l
Next Resectionl
the preoperative imaging studies, such as plain
Additional
5 mm Incremen
s
radiographs, CT scans and MRI of the tibia to
Stem
Extensio
n
determine a safe resection level.
The minimum proximal tibial resection level is
to assess the following: approximate resection
105 mm with a 12 mm hinged
Steminsert bearing.
Extensio
n the 73 mm
This minimum resection level
includes
level; joint line; the proximal tibial replacement
position and segmental component (if needed)
proximal tibial replacement component length
to restore leg length; and the diameter and
plus the 12 mm hinged insert-bearing plus the 20
length of the tibial stem extension that could
mm stem component collar height. If additional
be used (to provide adequate fixation and
replacement length is needed, the 25 mm
stability in the remaining host tibial diaphyseal
segmental component is the shortest segment
bone).
available making the 130 mm the next level of
resection (Figure.4.1 see page 38).
• Evaluate the femur to confirm establishment
Proximal
Tibia
l
Replacemen
t
Componen
t
12 m
105 mm
of the knee joint line and assess any
Segmental components are then available in 5
abnormalities or deficiencies that may exist.
mm increments alone or in combination with
Universal
Hinged
otherLPS
segmental
components to adjust leg length.
Proximal
Tibia
l
Proximal
Tibia
l
Replacemen
t
Replacemen
t
Componen
t
Componen
t
12 m
12 m
73 m
73 mm
73
105 mm
130 mm
20 m
20 m
25 m
20 m
Stem
Extensio
n
Stem
Extensio
n
Segmenta
l
Componen
t
Proximal
Tibia
l
Replacemen
t
Componen
t
Minimum
Resection Lev
l
Next Resectionl
Additional
5 mm Incremen
s
Stem
Extensio
n
130 mm
25 m
20 m
Segmenta
l
Componen
t
Stem
Extensio
n
Figure.4.1
38
12 m
73 m
105 mm
130 mm
39
Surgical Technique
Proposed Level
of Femur
Resection
Distance
Record
After achieving proximal tibia and distal femur
If using a cemented stem, choose the final stem
exposure, mark the proposed tibial resection
that is smaller than the last reamer used to allow
level with the leg fully extended in a reproducible
for a circumferential cement mantle around the
position. Avoid knee flexion for consistency of
stem. For example, if a 15 mm IM reamer was
recording results. Mark a horizontal line on the
last used, an 11 mm stem would have a 2 mm
tibia 1 cm below the proposed resection level
Description
Description
cement mantle per side. If a 13 mm stem were
as a reference for use in leg length recording
used, there would be a 1 mm cement mantle per
and make a perpendicular vertical mark on the
side.
Description
Description
anterior crest of the tibia.
Do not ream the tibial canal to the cortical
Proposed Level
of Tibia
Resection
Mark another horizontal line on the femur, above
the level of the femoral component and in line
with the trochlear groove. Make these marks
Figure.4.2
Stem Extensions
with electrocautery, osteotome, marking pen or
When using a porous-coated stems, under ream
methylene blue (Figure.4.2). Record this distance
by 0.5 mm for a stem press fit application. If the
estimation prior to any resection and use for
remaining bone is fragile, consider line-to-line
future reference in the procedure.
reaming.
Tibial Resection
When a proximal tibial tumour resection is
100 and 125 mm straight lengths in cemented
required, excise the tumour and affected soft
and porous-coated options for tibial use. The table
tissue prior to any femoral bone resection. The
to the right reviews the stem options that are
tibia is then resected to healthy, diaphyseal bone.
available with DePuy LPS.
Femoral Preparation
When using a hinged component, follow the
technique for implanting the S-ROM® hinged
Once reaming is completed, prepare the tibial
femoral component and prepare the distal femur
resection osteotomy surface to help assure proper
for the S-ROM hinged femoral component
stem extension fit. The calcar planer/bevel reamer
(Surgical Technique cat. no. 0612-94-506). It is
produces an even cut surface and is designed to
mandatory to use the Universal femoral sleeve
cut an angled relief (bevel) in the bone to match
and stems due to the high torsional stresses from
the stem extension flare under the collar. This
soft-tissue loss.
helps to assure complete femoral stem extension
seating on the prepared diaphyseal bone surface.
Tibial Medullary Canal Preparation
Following the distal femoral preparation, ream
Use the calcar planer/bevel reamer with pilot that
the remaining tibial canal for the stem extension.
is at least 1 mm smaller than the last IM reamer
Straight stems are recommended for use in the
used (Figure.4.3 see page 40) and insert it into
No. 0612-35-050 (Rev. 2), for
tibia. The straight IM reamer is recommended for
the femoral canal. Sequential use of the bevel
the straight stem extension.
reamer with the pilots will prepare the bevel in
the remaining bone with more efficiency and
precision. Attach the assembled planer and bevel
reamer with the pilot to a power drill reamer
using the appropriate adapter. The calcar planer/
bevel reamer should be under power prior to
Figure.4.3
planing the resection cut.
40
41
Surgical Technique
Stem
Tria
l
This will minimise any resected bone chipping
Trial Reduction
caused by the calcar planer cutting blades. The
Following the tibia preparation for the stem
following are recommendations for using the
extension, perform a trial reduction. Record the
calcar planer/bevel reamer with cemented or
gap from the distal tibial resection to the level
porous stems:
of the contemplated joint line. Check leg length
restoration using the marks made previously
Sleeve Tria
S-ROM Hinge
d
Femoral Tria
l
Universal LPS
Tibial Hinged
Insert Trial
Hinge Pin T
Tibial Post
Tria
l
on the femur and tibia. Utilising this recording,
assemble the tibial replacement component,
segmental component (if needed) and distal stem
trials that would fill the gap of missing bone
(Figure.4.4 see page 42). If the proximal tibia
is available in one piece, an alternate method
chosen implant, the final bevel reamer with
is to record the resected bone. Assemble the
a pilot will be the 15.5 mm pilot. Note the
trial components, and from the joint line to the
pilot is undersized by 0.5 mm from the stated
resection line, evaluate the match of the trial to
size. For example a 15.5 mm pilot is 15 mm in
the resected bone (Figure.4.4 see page 42).
Reconstru
Distanc
Alignment
Mark
Proximal Tibia
l
Replacemen
t
Trial
reaming technique. If a 15 mm IM reamer was
The trial components are designed to snap
together and match the implant component
dimensions. Utilise the stem trial size to provide
enough stability to prevent “spinning” when
performing a trial reduction.
Straightm Ste
Tria
l
Figure.4.4
The trial stem size should closely match the size
of the last reamer and it can be 1 – 2 mm smaller
than the last IM reamer used depending on the
fit. Insert all trial constructs by hand and never
impact them into the canal. Insert the DePuy LPS
trial construct into the remaining proximal tibia
and mate with the trial S-ROM femoral hinged
cement mantle.
trial construct to assess fit, leg length, joint line,
Figure.4.6
joint stability, soft tissue tension and range of
Resurface the patella using a domed patella
motion (Figure.4.6).
1
2
replacement, such as the S-ROM dome patella
1
3
when using the S-ROM hinged component or the
4
2
5
SIGMA domed patella when using the DePuy LPS
6
distal femoral component.
7
3
8
9
4
10
11
12
5
13
14
6
15
16
7
Figure.4.5
42
43
Surgical Technique
Varying the hinged insert-bearing trials and/or
Use the S-ROM tibial impactor to insert the
segmental trials, if used, can help fine tune leg
implant construct. Orientate the implant’s
length adjustments. Use the trial construct to
anti-rotation slot with the alignment mark
assess proper component rotational orientation.
previously placed on the tibia. If using the porous
Once proper orientation is established, use the
stem, impact the construct in place using a mallet
anti-rotation slot (tab) on the trial to mark the
to strike the inserter and align the anti-rotation
tibia (Figure.4.6 see page 43). This mark serves as
tab with mark on the femur for proper alignment
an alignment guide when inserting the implant.
(Figure.4.7). Placement of a “prophylactic”
cerclage wire around the proximal end of the
Implant Assembly
remaining diaphysis may decrease the risk of an
intraoperative fracture during press-fit insertion of
a porous stem extension, particularly with fragile
implant components. The implant components
bone. Insert a cemented stem construct and align
use a Morse-taper design for locking. Assemble
as noted above. Remove the excess bone cement
them by hand with the tibial component
from around the implant collar.
Complet
Seatin
plateau placed on top of a clean, sterile cloth or
positioned on the S-ROM tibial assembly stand
The stem extension shoulder should be flush
with the stem pointing towards the ceiling.
to the tibia’s cut surface when using either the
cemented or porous stem extension (Figure.4.8).
Assemble the implant components and place
Compl
Seati
Alignment
M ark
Figure.24.1
Give meticulous attention to the stem’s position.
the impaction cap over the stem extension. Then
Failure to align the stem in proper rotation may
use a mallet to securely seat the tapers together
result in patellar instability.
Alignment
M ark
(Figure.4.7). There should be approximately a 1
Figure.4.7
mm gap between the component bodies after
Perform a final trial reduction. Make leg length
impaction.
adjustments and check joint stability by using the
Figure.4.8
trial-hinged tibial bearing trials prior to choosing
Implant Insertion
the final implant component.
If using SMARTSET MV bone cement to secure the
44
45
Surgical Technique
Use the locking pin to mate the distal femoral
If, due to grossly inadequate soft tissue integrity,
component to the Universal LPS tibial bearing
flexion beyond 90 degrees causes luxation of the
through the hinged tibial insert bearing. Pass the
hinged insert bearing out of the base of the tibial
locking pin through the S-ROM hinged femoral
component, the patient must have a knee brace
component and the LPS tibial insert-bearing
postoperatively to limit flexion to 90 degrees. In
bushings (Figure.4.9). It is important to note
such cases consider closing the wound with the
that the Universal DePuy LPS hinged tibial insert
knee in full extension.
bearing chosen must match the S-ROM hinged
femoral component. For example, if a small
S-ROM hinged femoral component size is used,
then the corresponding Universal DePuy LPS
meticulous wound closure to minimise the wound
hinged insert must be a small size component.
physical therapy or other adjuvant oncological
One method to secure the locking pin uses
treatments, such as radiation therapy and
manual pressure to push the locking pin through
chemotherapy.
until it “clicks” and locks into place. Another
method uses forceps to squeeze the locking
Typically close the wound over large bore drains to
pin while pushing the pin until it is completely
minimise hematoma collection.
seated in the square cut-out in the DePuy LPS
distal femoral component. After the pin is seated,
Postoperative Care
pressure is released from the forceps.
Individualise postoperative care. Many of these
procedures involve extensive dissections. The
Once the pin is securely locked, push the lock pin
patient’s activity and weight-bearing status
from the opposite side of insertion and confirm
will depend on the extent of the surgery, the
that it is captured and locked.
individual patient’s needs and the implant’s
fixation type. In general, motion is not allowed for
Figure.4.9
Closure
8 to 12 weeks to allow for extensor mechanism
One of the most important aspects of this
healing and to minimise postoperative extensor
procedure is the soft tissue reconstruction. Attach
lag.
the patellar tendon to the implant with heavy
sutures or MERSILENE tape. In order to further
The weight-bearing status is generally full with
secure the patellar tendon, raise the medial or
cemented stems. With cementless stems, the
lateral or bilateral gastrocnemius flaps and suture
weight-bearing status can be individualised based
them to the patellar tendon and the surrounding
on the patient’s needs. However, it is suggested
soft tissues.
for patients not on chemotherapy to adhere to
toe-touch weight bearing for eight weeks. For
The gastrocnemius flap(s) also fills the defect
patients on chemotherapy, 12 weeks is suggested.
left by the biopsy tract excision and covers the
implant. Use a split-thickness skin graft over the
exposed muscle flap at the biopsy track excision
site.
46
47
120 mm
80%-80%-80%-101%
Surgical Technique
Minimum Resection Length
Next Resection Length
Mid-shaft femoral Replacement
Stem
Extension
The following technique reviews the intended
Intercalary resection and reconstruction is a less
design and use of the instruments and implants
common procedure; however, the DePuy LPS
for this procedure and provides a general
allows for such reconstructions when necessary.
framework. Use techniques that best meet the
The indications for the implant’s use include
needs of each case, since each case is unique and
soft tissue sarcomas that have invaded bone,
with its own challenges. Consider the following
mid-shaft locations for primary bone sarcomas,
selected mid-shaft femoral metastatic lesions
Figure.24.1
and selected non-union of the femur’s mid-shaft.
Contraindications include active sepsis and
situations where insufficient remaining bone is
present to support the reconstruction.
to assess the approximate resection levels,
use of a segmental component (if needed) to
Stem
Extension
Other treatment options for these problems
restore leg length and the diameter and length
include use of segmental allografts fixed by
of the femoral extension stems that are used
intramedullary rodding or plate and screws, filling
to provide adequate fixation and stability in
the defect with bone cement and supplemental
the remaining host femoral diaphyseal bone.
fixation by IM rodding or plate and screw fixation
and amputation.
95 mm
Next
Resection Length
120 mm
5 mm
Increments
Use a surgical approach that best achieves
20 mm
The advantages of using the DePuy LPS for
the exposure needed for bone resection. It is
intercalary reconstruction compared to other
important to check leg length recordings and
options includes the ability for immediate
alignment prior to any bone resection. Take care
weight bearing and no reliance upon host bone
during surgery to avoid stretch injury to the
for allograft healing for long-term durability.
neurovascular structures. Use the preoperative
This healing may be compromised because
imaging studies such as plain radiographs, CT
95 mm
120 mm
80%-80%-80%-101%scans and MRI to determine the resection levels.
of postoperative adjuvant treatment such as
Dovetail
Intercalary
Segmental
Components
Minimum Resection Length
Next Resection Length
radiation therapy or chemotherapy.
55 mm
The minimum intercalary femoral resection
Stem
20 mm
The system is modular and comprised
Extension of two
amount is 95 mm. This minimum resection
medullary stems in the proximal and distal femur
level includes the 55 mm intercalary segment
joined by Morse-taper locking with a two-piece
component length, plus the two 20 mm stem
intercalary (female/female) segmental component.
collar heights (Figure.5.1 see page 48). If
If necessary, segmental segments can be added
additional replacement length is needed, the
between the stems that adjust for resection length
25 mm segmental component is the shortest
differences to restore leg lengths.
segment available, making the 120 mm the
Figure.5.2
next level of resection (Figure.5.2). Segmental
components are then available in 5 mm
Figure.5.1
increments alone or in combination with other
segmental components to adjust leg length.
ƒ: Dovetail Resect Mid-Femur
Rev DePuy Fig 5.1a
2/1/03; 3/29/03; rev 10/16/04
48
Minimum
Resection Length
49
Surgical Technique
After exposing the femur, mark horizontal lines on
the femur 1 cm above and below the anticipated
Ream the remaining femoral canals for the stem
resection levels to allow for a recording to recreate
extension (Figure.5.4). A straight IM reamer is
leg lengths. Record this prior to any resection and
recommended for the straight stem extension.
use it for future reference in the case (Figure.5.3).
Proposed Level
of Proximal
Femur Resection
In order to restore proper rotational orientation
If using a cemented stem, which is commonly the
after reconstruction, make vertical lines
case in oncology use, choose a final stem that is
perpendicular to the horizontal lines to indicate
smaller than the last reamer used to allow for a
the femur’s anterior surface. Make these using
an osteotome, electrocautery, marking pen or
For example, if a 15 mm IM reamer was used
methylene blue.
last, an 11 mm stem would have a 2 mm cement
mantle per side.
Femoral Shaft Resections
Distance
Record
Proposed Level
of Distal
Femur Resection
Following tumour resection, create the proximal
Do not ream the femoral canal to cortical bone
and distal osteotomies using an oscillating saw.
for cemented application. Leave some cancellous
bone for cement interdigitation.
Once the bone and soft tissue resection has been
performed, prepare the remaining host femur.
When using a porous-coated straight stem
extension, under ream by 0.5 mm for press-fit
application of the straight stems. If the remaining
bone is fragile, consider line-to-line reaming.
Proximal Femoral
Reaming
Figure.5.4
Do not use a cementless application in patients
with marked osteopenia or who are deemed to
Distal Femora
Reaming
be at risk for an intraoperative fracture. Placement
of a “prophylactic” cerclage wire around the
proximal end of the remaining diaphysis may
decrease the risk of intraoperative fracture during
Figure.5.3
insertion of the press-fit stems or with fragile
bone.
The DePuy LPS stem straight stem extensions
are available in 100 and 125 mm lengths with a
range of diameters in 1 mm increments (see chart
on page 53).
50
Proximal Femoral
Reaming
51
Surgical Technique
Description
Description
Once reaming is completed, prepare the resection
to help assure proper stem extension fit. The
calcar planer/bevel reamer produces an even cut
surface and an angled relief (bevel) in the bone to
match the stem extension flare under the collar.
This helps to assure complete stem extension
seating on the prepared diaphyseal bone surface.
cement mantle.
Choose a calcar planer and insert a bevel reamer
with a pilot that is at least 1 mm smaller than
Trial Reduction
the last IM reamer used (Figure.5.5) and insert
Following the femur preparation for the stem
it into the femoral canal. Sequential use of the
extensions, perform a trial reduction. Utilising the
bevel reamer with the pilots will prepare the bevel
preosteotomy recording, assemble the appropriate
in the remaining bone with more efficiency and
diameter trial stem extensions, intercalary
precision.
segmental trial and segmental component, if
Description
Description
needed, that would fill the missing bone gap. An
Attach the assembled planer and bevel reamer
alternative distance estimation method is to use
with a pilot to a power drill reamer using the
the resected femoral length to match total trial
appropriate adapter. The calcar planer/bevel
component length (Figure.5.6).
the calcar planer/bevel reamer with cemented or
porous stems:
reamer should be under power prior to planing
the resection cut. This will minimise any resected
bone chipping caused by the calcar planer cutting
blades. The following are recommendations using
Figure.5.5
that is at least 1 mm less than the final chosen
implant and finish with a final bevel reamer
pilot that matches the final stem extension
chosen implant, the final bevel reamer with a
pilot will be the 15.5 mm pilot. Note, the pilot
is undersized by 0.5 mm from the stated size.
No. 0612-35-050 (Rev. 2), for
For example, a 15.5 mm pilot is 15 mm in
1
2
1
2
5
6
7
3
8
4
3
ream technique. If a 15 mm IM reamer was
9
4
10
11
12
5
13
14
6
15
16
7
Figure.5.6
52
53Meas DT Mid-Femur
ƒ:
Rev DePuy Fig 5.5
Surgical Technique
The trial stem should closely match the last IM
Use the trial construct to mark proper rotational
reamer or it can be 1 – 2 mm smaller than the
orientation of the components. To establish
last IM reamer used. Utilise the stem trial size to
rotational alignment, centre the anti-rotation slot
provide enough stability to prevent “spinning”
(tab) on the femur’s anterior aspect and mark
when performing trial reduction. Insert all trial
the femur proximally and distally. These marks
stems by hand and never impact them into the
will serve as alignment guides on either side of
canal. The intercalary trial should be unscrewed
the femur when inserting the stems to align
so that it is in two pieces. Each intercalary trial is
the limb so that it is in the correct rotation after
then attached to each stem trial. The matching
being coupled together through the intercalary
dovetails of the intercalary trials are slid into
segmental component (Figure.5.7).
Impaction
Cup
each other and the knurled locking ring is turned
Check
Recorded
Distance
Alignment
mark
clockwise to lock the trial construct together
Implant Assembly and Insertion
(Figure 5.7). Alignment and limb restoration
After successful trial reduction, implant assembly
length are assessed. Once a satisfactory trial
and implantation can proceed.
Stem
Extension
reduction is completed, mark the proximal distal
femur in line with the anti-rotation slots. These
On the back table, impact the male taper of
marks are important to provide a reference for
each stem with the female taper of each dovetail
alignment when inserting the implanted stems in
intercalary component. Assemble the intercalary
the femur.
segment by hand with the selected stem and
place the intercalary component on a sterile cloth
ƒ: Assemb Trial Dovetail 1
Rev DePuy Fig 5.5
3/29/03; rev 5/27/03; 7/22/03; 10/16/04
Figure.5.7
If the soft tissues are excessively tight and the
on the back table with the stem pointing towards
limb is lengthened, consider soft tissue releases,
the ceiling. Place the impaction cap over the
additional resection and/or varying the segmental
stem and use a mallet to impact the component
trial (if used) to address this situation. If the limb
tapers together with multiple blows to securely
length is short and needs to be lengthened,
seat the components (see Figure.5.8). Repeat
consider use of a segmental trial. Additional
this procedure with the other selected stem and
resection may be necessary if the segmental trial
intercalary component.
Dovetail Intercalary
Segmental Component
Figure.5.8
was not used previously and its use is greater then
ƒ: DT Trials Mid-Femur
DePuy Fig 5.6-revised
2/24/03; 4/9/03; 5/27/03; rev 10/16/04
the amount of shortening. If any additional bone
If using SMARTSET MV bone cement to secure
is resected, it is recommended that the femoral
the femoral stems to the host bone, follow the
canal be reamed further distally and proximally
manufacturer’s recommended procedures to mix,
followed by finishing preparation using the calcar
deliver and pressurise the bone cement into the
planer/bevel reamer.
femoral canal openings.
Tighten
Ring
Down
ƒ: Assemb Trial Dovetail 2
Rev DePuy Fig 5.5
3/29/03; rev 5/27/03; 7/22/03; 10/16/04
54
55
Surgical Technique
Insert the stem/intercalary construct into the distal
On occasion, if there is significant soft-tissue
end of the femur, aligning the anti-rotation slot of
fibrosis (e.g. from prior surgery, trauma,
the stem with the mark previously made on the
irradiation, etc.) then extremity shortening may
anterior surface of the femur. Clean any cement
be necessary to minimise soft tissue tension and
from around the stem collar and bone junction.
allow wound closure without undue tension.
Hold the stem until the bone cement hardens.
Typically close the wound over large bore drains to
Align the second stem/intercalary construct made
minimise hematoma collection (see Figure.5.10).
Figure.5.10
previously, and insert it into the femur’s proximal
end and hold it until the bone cement hardens.
Postoperative Care
Again, remove excess cement from the stem collar
Individualise postoperative care. Many of these
and bone junction. Once both stem constructs are
procedures involve extensive dissections. The
securely cemented in place, slide the two dovetail
patient’s activity and weight-bearing status
components of the intercalary device together
will depend on the extent of the surgery, the
(Figure.5.9). Secure the components by inserting
individual patient’s needs and the implant’s type
the locking pin into the threaded through hole
of fixation.
(from either side) and tighten by turning the
Allen key (included with the device) in a clockwise
The weight-bearing status is generally full
direction until completely tightened.
with cemented stems. With cementless stems,
individualise the weight-bearing status based on
Closure
the patient. However it is suggested for patients
One of the most important aspects of this
not on chemotherapy to adhere to the toe-touch
procedure is the soft tissue reconstruction.
weight bearing for eight weeks. For patients on
Soft tissue closure should completely cover the
chemotherapy, 12 weeks is suggested.
prosthesis. In oncological applications, when
Figure.5.9
soft tissues are resected to achieve a wide bone
tumour margin, the amount of remaining soft
tissue coverage is reduced. In this case, remaining
musculature mobilisation may be necessary to
achieve proper soft tissue coverage around the
prosthesis.
ƒ: Connect DT Mid-Femur
Rev DePuy Fig 5.8
2/24/03; 4/9/03; 5/27/03; 10/16/04
ƒ: Final DT Mid-Femur
Rev DePuy Fig 5.9
2/24/03; 4/9/03; 5/27/03; 10/16/04
meticulous wound closure to minimise wound
physiotherapy or other adjuvant oncological
treatments, such as radiation therapy or
chemotherapy.
56
57
Appendix I.
Appendix II.
Technique to Disassemble Implant Tapers
Use of Metaphyseal Sleeves
Align over
Slot
Although the DePuy LPS system components are
Intraoperative Planning
designed for secure implant taper locking, it is
The minimum distal femoral resection level is
possible to disassemble the tapers if needed. The
60 mm when using the X-small distal femoral
disassembly tool is designed to separate the tapers
replacement component and 50 mm when
quickly and efficiently.
using the XX-small distal femoral replacement
Disconnect
component. Additional sleeve adapter
The disassembly tool’s jaws are aligned with
components are available in +0 mm, +5 mm, and
the implant’s anti-rotation slots. It is critical to
+10 mm to bring down the level of the expected
match the disassembly instrument’s “half-moon”
joint line.
shape with the implant anti-rotation slot’s
“half-moon” shape. Once aligned, squeeze the
After achieving distal femur and proximal tibia
disassembly tool’s handle and push down quickly
exposure, mark the proposed distal femoral
on the disassembly tool (Figure.6.1). The force
resection level with the extremity fully extended in
generated in the anti-rotation slots will produce
a reproducible position. Avoid distance estimates
adequate force to disassemble the taper junction
with the knee in flexion for consistency of
(Figure.6.2).
recording results. Make a horizontal line on the
Proposed Level
of Femoral
Resection
femur 1 cm above the proposed resection level as
Distance
Record
a reference for use in leg length recording. Then
mark a perpendicular vertical line on the anterior
Figure.6.1
cortex midline in line with the femoral trochlear
groove. This mark serves as a reference for correct
femoral prosthesis rotational alignment.
Make another horizontal line 1 cm below the
Proposed Level
of Tibia
Resection
proposed resection level on the tibia for use as
a reference in leg length recording. These marks
can be made with electrocautery, osteostome,
Align over
Slot
marketing pen or methylene blue (Figure.6.3).
Record this prior to any resection and use for
Disconnect
future reference in this case.
Figure.6.3
Another recording that is useful is the distance
from the natural joint line to the horizontal line
marked on the femur. This is a useful reference
when re-establishing the level of the joint line.
Figure.6.2
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59
Appendix II.
Use of Metaphyseal Sleeves
Femoral Preparation
The last broach used will be the femoral sleeve
Make the appropriate distal resection as required.
size. The sleeve can be prepared to sit flush in the
Remember the extra 20 mm resection is no
bone or slightly proud depending on the amount
longer needed because the LPS stems will not be
and quality of remaining bone.
used. Therefore, take a 50 mm/60 mm resection
depending on the femoral size chosen and if any
Trialing
segments will be used.
After broaching is complete, the femoral bone is
Figure.6.6
ready for trialing. There are three corresponding
Prepare the femoral canal with the M.B.T. Revision
trials for the offset sleeve adapters, corresponding
reamers. Begin with the introductory reamer
to the 0, 5, and 10 mm offset options. These
and subsequently ream to larger sized reamers
offset adapters will adjust the amount of distal
until the desired fit is achieved. The reamers
offset of the final component by either 0 mm,
are available in 1 mm increments, beginning at
5 mm, or 10 mm. These trials have the same
10 mm. The final reamer must be even sized to
spring-coil lock trialing system as the rest of the
match the final Universal stem size. Use reamers
DePuy LPS instrumentation. Utilise the Universal
to prepare the canal. When using the press fit
femoral sleeve trials located in the SIGMA Femoral
Universal stems, line-to-line reaming is suggested
Adapter case and M.B.T. stem trials located in the
(Figure.6.4). If power reaming, it will be necessary
M.B.T. stem trial case.
to attach the modified Hudson adapter to the
Figure.6.4
straight reamer. Note that the reamer shaft
Implant Assembly
contains markings in 25 mm increments to
accommodate the various Universal stem/sleeve
length combinations. Another option to determine
implant components. Use the implant impacting
reamer depth is to record the trial assembly
stand to stabilise the implant components for
against the reamer.
assembly and impaction. The implant components
use a Morse-taper design for locking.
After reaming the intramedullary canal, attach
the threaded shaft to the broach reamer and then
First assemble the DePuy LPS distal femoral
to the appropriate stem trial as determined by
replacement component, any segment
straight reaming. Ream as appropriate.
components and offset sleeve adapter. Once
impacted together, assemble the chosen Universal
Figure.6.5
When using the broach reamer, the next smaller
stem to the revision sleeve and thread the stem
diameter stem trial may be used to allow easier
onto the sleeve. Grasp the sleeve with the tibial
reaming. The broach reamer will be necessary
sleeve clamp and use the stem extension wrench
when utilising a 20 mm sleeve and for the
to grasp the Universal stem. Tighten as shown in
beginning of larger sequential broaching when
Figure.6.6. Apply sufficient force to both wrenches
a 31 mm or larger sleeve is used. After broach
to secure the stem. Then assemble the sleeve/
reaming has been completed, attach the 31
stem to the chosen distal femoral component
mm broach to the broach impactor (Figure.6.5).
construct and impact using the femoral stem/
Attach the appropriate stem trial to the broach
sleeve impactor found in the Femoral Adapter
as determined by straight reaming. Sequentially
instrument case. Final assembled components will
broach to the desired dimension of 31, 34, 40,
look like those in Figure 6.7.
Figure.6.7
or 46 mm. At each size, assess the broach’s
rotational stability. If the stability of the broach is
unsatisfactory, move up to the next larger broach
size.
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DePuy LPS™

Transcription

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