AllofitST surgical tech

8/7/2019 AllofitST surgical tech

1/16

ALLOFITACETABULARHIP SYSTEM

SurgicalTechnique

Unique ridgelocksurface designed foreasy implantationand stability


2/16


3/16

1

ALLOFIT ACETABULARSYSTEM

Developed in conjunction with:

Nikolaus Boehler, MD

University Professor of Orthopedic Surgery

General Hospital

Linz, Austria

Wolfgang Schwaegerl, MD

University Professor of Orthopedic SurgeryVienna, Austria

CONTENTS

INTRODUCTION ................................................................... 2

PREOPERATIVE PLANNING ............................................ 3EXPOSURE OF THE ACETABULUM ............................. 3

REAMING THE ACETABULUM ....................................... 4

SELECTION OF IMPLANT SIZE .....................................5

IMPLANTING THE TITANIUM SHELL WITHOUT

SCREWHOLES ....................................................................... 6

IMPLANTING THE TITANIUM SHELL WITH

SCREWHOLES ....................................................................... 7

INSERTION OF SCREWS...................................................8

FITTING OF THE TRIAL INSERT ....................................9FITTING OF THE CUP INSERT ......................................10

REMOVING THE LINER ...................................................10

ORDERING INFORMATION ........................................... 11


4/16

2

ALLOFIT ACETABULAR

SYSTEMSince its first use in 1993, the Allofit Acetabular

Cup System has gained popularity among

hundreds of orthopedic surgeons. It provides the

surgeon with a reliable prosthesis that is easy

to handle. The surgeon can individually select

the acetabular components most suitable in an

economical and practical framework.

Its unique geometry assures minimal bone

resection and aims to reestablish a secure and

physiological load transfer through the periphery

of the cup. The Allofit Acetabular Cup System

features a patented Ridgelock macro structure

that greatly supports primary stability of the

3mm titanium shell. Permanent secondary

fixation is achieved by the choice of a grit-blasted

commercially pure titanium surface.

To prevent failure due to incomplete metal

backing of the insert, the Allofit System offers

sufficient polyethylene wall thickness for inserts.All screwholes in the titanium shell are designed

so they can be sealed. The congruent insert

is seated and secured in the shell by a snap

mechanism that firmly holds the insert in place.

Allofit offers an industry-leading set of alternative

bearing options, addressing the most dominant

complications in THAlate loosening and

dislocation.

Durasul highly crosslinked polyethylene, which has shown nomeasurable wear on a physiological hip simulator. Available instandard and hooded options and 28 and 32mm articulating

diameters.

Metasul metal-on-metal inserts used for over 15 years in morethan 200,000 patients worldwide. Available in standard andhooded options and 28mm articulating diameter.

Sulene conventional polyethylene with increased crosslinkingand improved long-term stability due to gamma sterilizationunder nitrogen gas atmosphere. Available in 28 and 32mmarticulating diameters.


5/16

3

Preoperative PlanningPreoperative planning is undertaken using the

X-ray templates and a current X-ray of the pelvis,

in which the inferior edge of the symphysis liesin the center of the picture. The object of the

planning is to determine the most favorable

position of the implant and its approximate

size, as well as to anticipate possible operative

difficulties. A stable acetabular floor capable of

bearing loads and a sol id lateral bony cover are

desirable. The prerequisite for the implantation of

a primary stable cup is an extensively maintained

bony circumference of the acetabulum.

In dysplasia cases, the pre-operative planning

helps in deciding whether the implant position

must be strengthened by bone graft material.

The axis of the artificial joint should approximate

physiological conditions as closely as possible.

The opening plane of the cup should form an

angle of 40-45 to the pelvis horizontal line.

The subchondral sclerosis line between oriel

and lacrimal figure serves as a reference point

for estimating the cup diameter. The cup will

receive an anteversion of 10-15 intraoperatively.

It is also to be kept in mind that the correct

cup orientation depends on the position of the

femoral implant.

ApproachAny usual approach is possible.

Exposure of theAcetabulumThe capsule is preferably excised in its entire

circumference to the extent that an easy

introduction of reamers is possible. Remove

fibrous, cartilaginous and bone structures

preventing the preparation of the acetabulum.

Fig. 1


6/16

4

Fig. 2

Reaming the AcetabulumThe next stage is preparation of the

acetabulum with the spherical reamers until

the predetermined size has been reached. The

desired objective is based upon the following

conditions:

anatomically formed implant support

preservation of bone stock to assure a solid

support of the implant

certainty of anchoring the cup shell in good

vascular bone

The objective is the creation of the geometrical

and physiological requirements for a primary and

permanently stable implantation of the titanium

shell.

Important: Extreme caution must be used when

reaming in order to prevent excessive removal

of bone and not to alter the morphology of the

acetabulum.

The central acetabular floor is first reamed

with a relatively small reamer and deepenedaccording to the preoperative planning. The use

of centering pins is optional. When the necessary

depth has been reached, the reamer is moved to

an inclination of about 40 and a hemispherical

support is formed with the use of larger reamers.

This cranial reamer direction is maintained until:

1. the necessary depth has been attained; and

2. 50-60% of the acetabular roof has been

reamed to bleeding bone.

The anterior and posterior acetabular roof must

remain stable and solid. The reaming process

has ended when these conditions have been

achieved.

To obtain optimal implant support and to avoid

thermal necrosis, the final reamer should be

operated by hand. In normal cases, it will be

introduced to a depth such that its equator

is entirely covered by bone. Dysplastic hipsrepresent an exception because it is necessary to

create an additional abutment.


7/16

5

Selection of the ImplantSizeIt is possible to test whether a cup of a given

diameter can be implanted in the optimumposition with the aid of the trial shell. The size

indication of the trial shell corresponds to the

reamer last used. After attachment to the cup

setting instrument, the trial shell is tapped in

up to the bony acetabular floor at the desired

abduction and anteversion. It should show stable

seating under pulling, rotating and careful tilting

loads. The contact between acetabular floor and

trial shell can be tested with the measurement

hook, after the setting instrument has been

unscrewed.

If the trial shell does not have a sufficiently firm

seat, it must be checked as to whether the edge

of the trial implant is anchored in bone. If this is

not the case, the acetabulum must be suitably

deepened with the reamer last used. If the trial

shell is not seated firmly enough in spite of a

sufficient bony enclosure, the next largest trial

shell is selected. In case of soft bone, additional

primary anchoring with at least two cancellous

bone screws should be performed.

Caution: To protect the acetabulum, the trial shell

is about 1mm smaller than the implant of the same

size designation. This is because the definitive

prosthesis has a surface macro structure that is not

present on the trial shell. The implant will thus have

a firmer seat compared to the trial.

The trial shell is then removed by tipping out.

Fig. 3

SELECTION OF THE IMPLANT SIZE

Size marked onreamer, shell,

implant

Actualtrial shell (mm)

Actual sizeimplant (mm)

Correspondingliner size

46 47 48 FF

48 49 50 GG

50 51 52 HH

52 53 54 II

54 55 56 JJ

56 57 58 KK

58 59 60 LL

60 61 62 MM

62 63 64 NN

64 65 66 OO

66* 67 68 PP

68* 69 70 QU

*sizes not available without screwholes


8/16

6

Implanting the TitaniumShell without ScrewholesThe titanium shell is completely screwed to the

setting instrument and tapped in with the desiredabduction and anteversion. The anteversion

depends on the selected operative approach, the

anatomical conditions and the femoral implant.

It is absolutely necessary to align the cup before

final impaction and to maintain the selected

setting direction.

The measurement hook is used to check whether

the implant was driven to the acetabular floor. As

can be seen in Figure 7, because of the specificgeometry of the cup, a small gap of about 1mm

might be present at the dome area even if the cup

is completely seated. The shell must maintain its

stable seating under pulling, rotational and tilting

loads.

A threaded dome hole plug is supplied with every

implant. The hole at the pole of the titanium shell

must be seated with it, otherwise the cup insert

cannot be mounted correctly. The dome holeplug is placed on the corresponding placement

instrument and screwed into the borehole.

If a trial reduction with a trial insert is planned,

do not insert the dome hole plug (see page 9).

Fig. 4

Fig. 5


9/16

7

Implanting the TitaniumShell with ScrewholesThe titanium shell is completely screwed to the

shell setting instrument and is tapped in withthe desired abduction and anteversion. The

anteversion depends on the operative approach

selected, the anatomical conditions, and the

femoral implant. It is absolutely necessary to

correctly align the shell before final impaction,

since its position can no longer be altered

afterwards.

A notch in the equator of the shell indicates the

main direction of the screwholes. The holesmust be placed correctly in the direction of

the resulting hip forces. No other orientation is

suitable biomechanically and such an orientation

may moreover entail the danger of vascular and

nerve lesions by the screws.

The measurement hook is used to test whether

the implant was driven to the acetabular floor. As

can be seen in Figure 7, because of the specific

geometry of the cup, a small gap of about 1mmmight be present at the dome area even if the cup

is completely seated. The shell must maintain

its stable position under pulling, rotational and

tilting loads.

A threaded dome hole plug is supplied with every

implant. The hole at the pole of the titanium shell

must be sealed with it, otherwise the cup insert

cannot be mounted correctly. The dome hole

plug is placed on the corresponding placement

instrument and screwed into the borehole.

If a trial reduction with a trial insert is planned,

the dome hole must not yet be closed (see page

9).

Fig. 6


10/16

8

Insertion of ScrewsFlat-head cancellous bone screws ( 6.5 mm,

reference #4301-07-015/070) must be used.

To simplify the initial insertion of the screws,

3.2mm holes are drilled through the subchondral

bone. The use of an angular drill gear with a drill

guide is recommended because it facilitates the

correct orientation of the holes in the center of

the screw funnel and vertically to the shell and

off-center insertion of the screws can lead to

damage of the screw or the screwhole and to a

possible dislodgement of the shell.

Tapping of the drill holes is only recommended in

cases of especially hard bone.

Since the screws are only to be anchored in

cancellous bone, lengths of up to 30mm are

normally sufficient. The screws must not

penetrate the opposite cortex. The geometry

of the screw funnel permits the screws to be

oriented within a range of 30 degrees.

Caution: The specified Ti-6Al-4V screws have a

lower shearing resistance than screws made of

steel or CoCrMo alloys.

It is recommended to check whether all screws

are completely seated before impacting the

insert. Projecting screw heads would make the

fitting of the cup insert impossible.

Screwholes in the titanium shell that are not

used can each be sealed with a screw plug.

The plug is placed on the appropriate setting

instrument and fixed in the screw funnel of thetitanium shell with a light tap. These screw plugs

are intended for one-time use only, and cannot

be removed any more once inserted.

Fig. 7

Fig. 8


11/16

9

Fitting of the Trial InsertWash the operative site thoroughly and carefully

clean the titanium shell.

It is recommended to manually place the trialinsert into the implanted shell.

The trial insert can be fixed into the titanium

shell by screwing in the attachment screw into

the dome hole of the implant. If the dome hole

plug has already been placed into the shell, it

must temporarily be removed.

Femoral ComponentIf alternative bearing surfaces are used, caremust be taken to select the appropriate femoral

head.

After implanting the femoral component, a trial

reduction is made to determine the correct size

of acetabular insert to be implanted. The trial

insert is then removed.

Fig. 9


12/16

10

Removing the LinerIf the disassembly of an already firmly seated

insert becomes necessary, the following

procedure is often successful: A cancellous

bone screw is inserted into the polyethylene

insert after making a small pilot drill hole. This

is done centrally in the case of polyethylene

inserts and decentrally between articulating

surface and shell edge with Metasul inserts, ifthe polyethylene body is sufficiently strong for

the purpose. It is also possible to attempt to

lever out the insert at the edge with one or two

osteotomes.

The inside edge of the shell, where the locking

mechanism for the insert is located, must be

protected if a new insert is to be fitted.

If a new insert can no longer be reliably anchored

in the old shell, the shell must be replaced.

Follow-up TreatmentA partial loading of the operated hip during the

first 6 weeks is advisable.

Fitting of the Cup InsertInterposed tissues in the titanium shell or at the

shell edge must be avoided since they prevent

the insert from snapping in. The shell edge must

be free from any tissue and particular attention

must be paid to the posterior-inferior bony edge

of the acetabulum.

Caution: The dome hole plug must be properly

inserted before impaction of the insert. It is

important that the dome hole plug is in place as it

plays a vital role in the alignment of the insert.

The size of cup inserts is indicated with a

letter code. This code corresponds to the size

indicated on the corresponding titanium shell

(see table on page 5) The appropriate modular

liner attachment is screwed onto the liner

impactor.

The insert is then attached to the setting

instrument, introduced into the cleaned shell,

and is carefully centered. The polyethylene guide

nipple must be centered in the hole of the dome

hole plug before impaction.

A couple of firm hammer blows on the setting

instrument are sufficient to snap the insert into

the shell. Once fully impacted, the phase of the

liner will be approximately 2mm above the rim of

the titanium shell. If the insert was not properly

aligned, deformation of the guiding nipple might

occurthe insert can not be impacted and a new

insert must be used.

In order to avoid any scratching of the delicate

surface, Metasul liners must be handled with

care.

Note: The modular liner attachment for Metasul

28mm liners can also be used for polyethylene

28mm liners.

Fig. 10


13/16

11

Ordering InformationALLOFIT SHELLS

Catalog No. Description

4242 Allofit Shell 46/FF

4243 Allofit Shell 48/GG4244 Allofit Shell 50/HH

4245 Allofit Shell 52/II

4246 Allofit Shell 54/JJ

4247 Allofit Shell 56/KK

4248 Allofit Shell 58/LL

4249 Allofit Shell 60/MM

4250 Allofit Shell 62/NN

4251 Allofit Shell 64/OO

ALLOFIT-S SHELLS


4262 Allofit-S Shell 46/FF4263 Allofit-S Shell 48/GG

4264 Allofit-S Shell 50/HH

4265 Allofit-S Shell 52/II

4266 Allofit-S Shell 54/JJ

4267 Allofit-S Shell 56/KK

4268 Allofit-S Shell 58/LL

4269 Allofit-S Shell 60/MM

4270 Allofit-S Shell 62/NN

4271 Allofit-S Shell 64/OO

4272 Allofit-S Shell 66/PP

4273 Allofit-S Shell 68/QU

ALLOFIT DOME HOLE PLUG


001.00004.000 Dome Hole Plug

ALLOFIT SCREWHOLE SEALS


001.00004.001 Screwhole Seals 7 pcs.

STANDARD METASUL INSERTS


01.00010.407 Alpha Metasul 28 Standard GG/28

01.00010.408 Alpha Metasul 28 Standard HH/28

01.00010.409 Alpha Metasul 28 Standard II/28

01.00010.410 Alpha Metasul 28 Standard JJ/28

01.00010.411 Alpha Metasul 28 Standard KK/28

01.00010.412 Alpha Metasul 28 Standard LL/28

01.00010.413 Alpha Metasul 28 Standard MM/28

01.00010.414 Alpha Metasul 28 Standard NN/28

01.00010.415 Alpha Metasul 28 Standard OO/28

01.00010.416 Alpha Metasul 28 Standard PP/28

01.00010.417 Alpha Metasul 28 Standard QU/28

HOODED METASUL INSERTS


01.00010.507 Alpha Metasul 28 Hooded GG/28

STANDARD DURASUL INSERTS


01.00013.206 Alpha Durasul 28 Standard FF/28

01.00013.207 Alpha Durasul 28 Standard GG/28

01.00013.208 Alpha Durasul 28 Standard HH/28

01.00013.209 Alpha Durasul 28 Standard II/28

01.00013.210 Alpha Durasul 28 Standard JJ/28

01.00013.211 Alpha Durasul 28 Standard KK/28

01.00013.212 Alpha Durasul 28 Standard LL/28

01.00013.213 Alpha Durasul 28 Standard MM/28

01.00013.214 Alpha Durasul 28 Standard NN/28

01.00013.215 Alpha Durasul 28 Standard OO/28

01.00013.216 Alpha Durasul 28 Standard PP/28

01.00013.217 Alpha Durasul 28 Standard QU/28

HOODED DURASUL INSERTS


01.00013.306 Alpha Durasul 28 Hooded FF/28

01.00013.307 Alpha Durasul 28 Hooded GG/28

01.00013.308 Alpha Durasul 28 Hooded HH/28

01.00013.309 Alpha Durasul 28 Hooded II /28

01.00013.310 Alpha Durasul 28 Hooded JJ/28

01.00013.311 Alpha Durasul 28 Hooded KK/28

01.00013.312 Alpha Durasul 28 Hooded LL/28

01.00013.313 Alpha Durasul 28 Hooded MM/2801.00013.314 Alpha Durasul 28 Hooded NN/28

01.00013.315 Alpha Durasul 28 Hooded OO/28

01.00013.316 Alpha Durasul 28 Hooded PP/28

01.00013.317 Alpha Durasul 28 Hooded QU/28

TRAY 1 (Sizes 46 to 58)


8604 Instrument Case Size 48 to 56

7139 Instrument Tray Cover

REAMERS


840.6002 Spherical Reamer 42










14/16

12

GUARD FOR REAMER


840.6043 Guard for Reamer 44








REAMER HANDLE


MPF310034 Reamer Handle

CENTERING PINS


840.6108 Centering Pin S

840.6109 Centering Pin M

840.6020 Centering Pin L

FIXATION SCREW


8635 Fixation Screw M8

TRIAL SHELLS


8609 Trial Shell Size 46







TRIAL INSERTS


8623 Trial Insert Size FF/28

8624 Trial Insert Size GG/28

8625 Trial Insert Size HH/28

8626 Trial Insert Size II/28

8627 Trial Insert Size JJ/28

8628 Trial Insert Size KK/28

8629 Trial Insert Size LL/28

TRAY 2 (Sizes 60 to 68)


8605 Instrument Case Size 60 to 68


REAMERS







GUARD FOR REAMER







TRIAL SHELLS







TRIAL INSERTS


8630 Trial Insert Size MM/28

8631 Trial Insert Size NN/28

8632 Trial Insert Size OO/28

8633 Trial Insert Size PP/28

8634 Trial Insert Size QU/28

TRAY 3 (Setting Instruments)


8606 Instrument Setting Instruments Case


SETTING INSTRUMENTS


7344 Impactor 28

8638 Impactor Straight for Titanium Shell

01.00019.005 Impactor Straight for Alpha Liner

01.00009.001 Dome Hole Plug Instrument

01.00019.004 Impactor Curved for Alpha Liner (optional)

8639 Setting Instrument for Screw Plug

5633 Control Hook

01.00019.107 Liner At tachment Standard 28

01.00019.109 Liner At tachment Hooded 28

01.00019.110 Liner At tachment Hooded 32

7843 Positioning Guide

75.12.00-10 Impactor Curved for Titanium Shell (optional)

8667 Adapter for Curved Impactor 75.12.00-10

(optional)


15/16

13

TRAY 4 (INTER-OP INSTRUMENTATION FOR BONE SCREWS)


9366-99-160 Inter-Op Acetabular System Screw

Instrument Case

9366-99-161 Inter-Op Acetabular System Screw

Instrument Tray #1

INSTRUMENTATION FOR BONE SCREWS


9366-00-015 Straight Hex Head Screwdriver

9366-00-016 Universal Joint Hex Head Screwdriver

9366-00-017 Universal Joint Hex Head Shaft (Optional)

9366-00-040 Flexible Depth Gauge

9366-00-041 Inter-Op Acetabular System Drill Bit Size

3.2mm/35mm

9366-00-042 Inter-Op Acetabular System Drill Bit Size

3.2mm/50mm


16/16

Please refer to package inserts for completeproduct information, including contraindications,warnings, precautions, and adverse effects.

Contact your Zimmer Representative or visit us atwww.zimmer.com.

AllofitST surgical tech

Documents

Transcript of AllofitST surgical tech