Anatomical Shoulder Inverse/Reverse Systemfaculty.washington.edu/alexbert/Shoulder/Surgery/... · 4 Anatomical ShoulderTM Inverse/Reverse Surgical Technique Foreword Total shoulder

From Anatomical to Inverse/Reverse

AnatomicalShoulderTM

Inverse/ReverseSystem

Surgical Technique

3Anatomical Shoulder Inverse/Reverse Surgical Technique

Table of Contents

Foreword 4

Indications, Contraindications 5

Biomechanical Concept 5

Description of the Implants 8

Overview of the Instruments 10

Preoperative Planning 11

Surgical Technique 13

Patient Positioning and Surgical Approach 13

Primary Implantation 14

From Anatomical to Inverse/Reverse 23

Revision 26

Ordering Information 27

Implants 27

Instruments 30

Appendix A 32

4 Anatomical ShoulderTM Inverse/Reverse Surgical Technique

Foreword

Total shoulder replacement has evolved as a biomechanically logical reconstructionof the shoulder. Anatomical reconstruction using the Anatomical Shoulder Systemallows the potential for the surgeon to restore the geometry of a normal joint, thusensuring good motion and pain relief, as well as durability of the reconstruction.

When there is severe distortion of osseous anatomy and loss of normal rotator cuff tendon structure, anatomical restoration of the glenohumeral joint is notpossible. Such patients who have severe loss of rotator cuff function may presentwith a pseudoparalysis as well as with pain. In such situations reconstruction in orderto restore function is possible using an inverse/reverse solution. The AnatomicalShoulder Inverse/Reverse option offers the ability for pain relief and restoration of function using the same humeral stem used for primary, revision, or fracture reconstructions.

5Anatomical ShoulderTM Inverse/Reverse Surgical Technique

The Anatomical Shoulder Inverse/Reverse design is based on the principle of kinematic balancing of theshoulder based on a model initiated by Grammont 1. The geometry reversesthe normal relationship between scapular and humeral components,moving the center of rotation medi-ally to increase the lever arm of the deltoid muscle, and lowers the humerusto increase tension of the deltoid. This allows the deltoid to compensatefor rotator cuff deficiency, both in terms of joint stability and function.

Biomechanical Concept

Difference of the center ofrotation (COR) betweenAnatomical Shoulder Stan-dard and Inverse/Reverse.With respect to the humeralshaft axis the COR is shiftedmedially and superiorly.

Humeral Stem Hemi Humeral Stem Inverse/Reverse

Cone Axis

MDM

S

DS

Cone Axis

Center of Rotation

Axis Axis

Reference1. Grammont P.M., Baulot E.; Delta

Shoulder Prosthesis for Rotator Cuff Rupture; Orthopedics 1993;16:65–68


Biomechanical TestingThe complexity of the shape of theimplants, the surface finish, the variousmanufacturing processes, and the range of mechanical properties of thematerials require that we validate our products through mechanical test-ing, computer modeling and calcula-tions. Computer modeling, especiallyfinite element analysis (FEA), is also regularly used to optimize the design in the development process. Thisensures a rapid development processand greatly increases the likelihood thata new implant will pass our stringentlaboratory tests.

Testing the PolyaxialScrew Connection The unique polyaxial screw connectionwas introduced in the AnatomicalShoulder Inverse/Reverse Glenoid toallow adaptation of the screw positionto the patient’s anatomy. The screwposition can be freely adjusted within30° arc and will then be locked in the chosen position with a locking cap. Theangular stability of this connection wastested using a static tilt test. The glenoid fixation was clamped to a fixture and the screw loaded vertically.The necessary force to cause a slip ofthe screw was measured. The force generated was greater then expectedclinical loads and provides stable fixation.

An example of a finite element analysis(FEA) of the glenoid fixation of the AnatomicalShoulder Inverse/Reverse System. The designwas optimized using FEA.

Experimental setup of the static tilt test

Polyaxial screw placement within 30° sub-sequent locking option for optimal systemstability.

F

30°


Testing of the Snap-Fit ConnectionA joint reaction force pointing outsidethe humeral cup causes a tiltingmoment, which can lever out the inlayfrom the cup. The snap-fit connection of the Anatomical Shoulder Inverse/Reverse was optimized to preventlevering out of the PE inlay even undersevere loading conditions like a sub-luxation. The static subluxation testsimulated a single abduction with 2 kghand load and then a subluxation was caused by applying a horizontaldisplacement. Abduction with less handload might occur more often, thereforea dynamic subluxation test was car-ried out. 250,000 subluxation cyclessimulating abduction with 1 kg handload were applied to prove the stabilityof the snap-fit connection. All testswere performed in water at 37 °C 2,3.

References2. Mroczkowski M.L.; Gronau N.;

Kralovic B. J.; The Effect of Center ofRotation and Rotator Cuff Functionon Reverse Shoulder Biomechanics;Data on file.

3. Gronau N.; Mroczkowski M.L.; Boss S.; Mechanical Testing ofReverse Shoulder ProsthesisStability; Abstract submitted to SFB 2006

Top picture showing the start position of thesubluxation test. A vertical load was appliedsimulating worst-case loading conditionsduring abduction. A controlled horizontaldisplacement was then used to cause subluxation, i.e. a severe edge loading. Thesnap-fit connection is strong enough to keepthe PE inlay in place even after 250,000 subluxation cycles (no lift-off, see circle onpicture above).

Levering out of PE inlay due to edge loading.During such a loading situation the snap-fitconnection must withstand an axial pull-outforce.

Center of Rotation

PE Inlay

Snap-Fit Region

Cup Dummy

Test Block

JointReaction Force

Initial Axisof Rotation

F

Horizontal Displacement

Center of Rotation


Description of the Implants

The standard Anatomical ShoulderStem is also used for the AnatomicalShoulder Inverse/Reverse Prosthesis.This arrangement allows the surgeonthe unique opportunity to revise a primary anatomical prosthesis to theinverse/reverse component withoutthe need for stem removal. Such revisionmight be necessary in the setting of anirreparable rotator cuff tear. This willgreatly simplify and shorten revisionsurgery since the need to remove a well-fixed stem is eliminated.

The Anatomical Shoulder Inverse/Reverse Humeral Cups can be placedonto the stem with the standard oval taper connection. The AnatomicalShoulder Inverse PE inlays will belocked into the humeral cups with a PE snap-fit solution.

On the glenoid side the AnatomicalShoulder Inverse Glenoid Fixation, withits convex design, preserves bone and has a central peg with antirotationfins for better primary stability. Thesuperior and inferior threaded pegs willbe used with the Inverse/Reverse ScrewSystem. The central peg has an ovaltaper to seat the Anatomical ShoulderInverse Glenoid Heads in place.

Anatomical Inverse/Reverse Humeral Cups• 4 offset and 4 version cups cover

range of lateralization, height andversion adjustments

• 0° retroversion (Standard) cups havea centralized taper connection thatplaces the humeral stem in a standard anatomical relationshipwith respect to the acromion

• 0° retroversion +6mm (MedialOffset) cups have a taper connectionthat is offset 6mm medial to the center of the cup. This places thehumeral stem in a more medialposition with respect to theacromion while increasing the heightof the prosthesis

• Both 0° retroversion cups come in a+9mm height option that increasesthe height and lateralization of theprosthesis. Combined with the 3polyethylene inlay options, 15mm ofadjustment can be made to the later-alization/height of the construct in3mm increments

• 4 additional version (control) humeral cups allows the intraopera-tive change or correction of stem version from +20° and –20°

• Oval taper inherently providesantirotation feature to a secure modular connection

Anatomical Inverse/Reverse PE Inlays• 2 diameters: 36mm and 40mm• 3 thicknesses: 0mm (standard)

3mm and 6mm• Antirotational design

Anatomical Inverse/Reverse Glenoid Heads• 2 diameters: 36mm and 40mm• Oval taper for secure fixation

The implants must be combined as follows: Combining different component sizes is not allowed.

Glenoid Head 36mm diameter with PE Inlay 36mm diameter

Glenoid Head 40mm diameter with PE Inlay 40mm diameter


Inverse/Reverse Screw System• 4.5mm diameter self-tapping

Inverse/Reverse Screws• Variable angulations to a maximum

of 30° in all directions for both, the superior screw in order to engagebase of the coracoid processand to obtain good cortical fixation, and also the inferior screw in order to engage the pillar of the scapula toobtain good cortical fixation

• A locking screw will fix and securethe desired angle of eachInverse/Reverse Screw

Anatomical Shoulder Stems• Anatomically designed for maximum

flexibility and stability• Short/long, cemented/cementless

(press-fit)• Modularity – from primary or tradi-

tional Anatomical to Inverse/Reverse

Anatomical Inverse/Reverse Glenoid Fixation• Press-fit design with locking screws

for primary fixation and stability• Convex design preserves more bone,

resists greater shear loads and moreevenly distributes forces at the fixationinterface versus flat backed designs

• Central, fluted post and superior/inferior pegs provide resistance torotational forces while accommodatingmodular taper connection and threadedlocking screw caps, respectively

• Titanium alloy based and roughenedmacrostructure enhance fixationpotential


Anatomical Shoulder Instrument Tray II

Anatomical Shoulder Glenoid Tray

The preparation and implantation ofthe Anatomical Shoulder Inverse/ReverseSystem should be carried out in a standardized manner. The technique hasbeen developed to require a minimalnumber of instruments to prepare thehumerus and glenoid for Inverse/Reverse applications. The correct use and handling of these instruments are arequirement for the success of the surgery.

Further instruments needed:• Anatomical Shoulder Instrument Tray I• Anatomical Shoulder Instrument Tray II• Anatomical Shoulder Glenoid Tray

For revision surgery, the following isalso needed:• Anatomical Shoulder Revision Tray

Overview of the Instruments

Insert Anatomical Shoulder Instruments Tray I

Anatomical Shoulder Instrument Tray I

Anatomical Shoulder Inverse/Reverse Trays


Preoperative Planning

Three radiographic images of the shoulder joint are required for planningthe operation:

1. Full-size true anterior-posterior view with neutral rotation (0°), centered onthe articular cavity

2. Axial view3. CT scan for planning glenoid insertion

Preoperative Planning – HumerusAn initial assessment is made of thebone in the superior and inferior aspectsof the glenoid, using radiographic and CT imaging, in order to determine thesuitability of the patient’s available bonestock for implant insertion.

Preoperative planning is also carried out, using AP and lateral shoulder radiographs of known magnification,along with templates to confirm the sizeand alignment of the implant.

Also see Preoperative Planning in theAnatomical Shoulder System SurgicalTechnique. Anatomical Shoulder™, Humeral Stem Revision

Cemented© All rights reserved, Zimmer GmbH, CH-8404 Winterthur, Switzerland,

08/2005, Lit. No. 06.00641.000x-WL

7 611814 542407

20cm

15 cm

10 cm

5cm

5cm

10 cm

15 cm

Magnification1.1:1

Rev

isio

nSiz

e7

REF

01.0

4215

.072

Rev

isio

nSiz

e9

REF

01.0

4215

.092

Rev

isio

nSiz

e12

REF

01.0

4215

.122

Rev

isio

nSiz

e14

REF

01.0

4215

.142

AS Inverse Humerus Shell Standard /+9

UncementedThe reference number must correspond to that of the prosthesis to be implanted.

© All rights reserved, Zimmer GmbH, CH-8404 Winterthur, Switzerland

08/2005, Lit.No. 06.01310.000-WL

5 cm

10cm

15cm

20cm

15cm

10cm

5 cm

D36

Size D36/D40 Standard +9

Size D36/D40 Standard

01.04223.10001.04223.36001.04223.40001.04223.10001.04223.36301.04223.403 01.04223.10001.04223.36601.04223.406

01.04223.19001.04223.36001.04223.400 01.04223.19001.04223.36301.04223.403 01.04223.19001.04223.36601.04223.406

D40

7 611814 762980

Magnification1.1:1

36

40

AS Inverse Glenoid Anchorage

UncementedThe reference number must correspond to that of the prosthesis to be implanted.

© All rights reserved, Zimmer GmbH, CH-8404Winterthur, Switzerland

08/2005, Lit.No. 06.01308.000-WL

5 cm

10cm

15cm

20cm

15cm

10cm

5 cm

Magnification1.1: 1

Size D36/D40REF-Number of the Product:

01.04223.20001.04223.24001.04223.23601.04223.01801.04223.02401.04223.02701.04223.03001.04223.03301.04223.03601.04223.04201.04223.048

D40

D36

7 611814 762997


Preoperative Planning – GlenoidMost indications for inverse/reversearthroplasty do not require correction ofthe version of the glenoid. Neverthelessthe glenoid should be evaluated on CTscans. Preoperative CT investigation isrecommended whenever a totalshoulder prosthesis is used. If there isa severe defect in the posterior glenoid,this must be corrected either by cor-rective reaming or by bone reconstruc-tion (using the resected head).

Glenoid version measured on the firsthorizontal CT section below the tip of the coracoid process (a) (anyosteophytes must be identified and,since they will removed, taken into consideration). Now determine the correction angle on the basis of themeasured glenoid version, knowing that the coronal (physiological) retro-version amounts to between 0˚ and 10˚(retroversion).

Enter the correction angle you have calculated on the glenoid positioningguide. Care must be taken both while drawing and during surgery, to ensure that the glenoid positioningguide lies on plane a–a.

Carry out cranio-caudal alignment of theKirschner wire (K-Wire) under visualmonitoring.

Then set this correction angle on the glenoid positioning guide, keeping in mind that one graduation markcorresponds to 5˚.

A preoperative CT scan is recommended for the purpose of determining the possibleneed for realignment of the articulating surface. The target value is a coronal (physio-logical) retroversion of between 0 and 10˚(retroversion).

Glenoid guidanceinstrument (one mark = 5°)

b = a preoperative – a postoperative

ba

a

b

a preoperative

a postoperative

a

a

a

a


Surgical Technique

Patient Positioning and Surgical ApproachThe patient should be placed in a beachchair position on the edge of the operating table (Fig. 1).

The arm must be freely movable and it must be possible to extend it fully. Anarmrest is optional.

The Anatomical Shoulder Inverse/Reverse System may be implanted using either a superior-lateral or delto-pectoral approach.

Superior-lateral or delto-pectoralapproach depends primarily on surgeonpreference and clinical parameters.

Revision surgery, for example, typicallydictates a delto-pectoral approach as itallows a longer humeral incision whenfaced with a difficult removal of thehumeral stem.

Superior-Lateral ApproachThe incision is made from the anterio-lateral acromial border downwardapproximately 4 cm.

Following subcutaneous dissection, the anterior and middle deltoid musclebundles are separated opposite the lateral margin of the acromion, usingblunt dissection. Care should be takento avoid any damage to the axillarynerve, which is located approximately4 cm distal to the acromion.

When the subacromial bursa is visible,gentle longitudinal traction in line with the limb will allow a retractor to be placed in the subacromial space.

The humeral head is dislocated byplacing the arm in retroversion andinternally rotated. To optimize the expo-sure, the anterior border and the restof the superior cuff can be resected.

Delto-Pectoral ApproachMake a skin incision in a straight linestarting from the lateral edge of thecoracoid as far as the insertion ofthe deltoid muscle. Seek the cephalicvein between the deltoid muscle andthe pectoralis major muscle. Make theapproach medial to the vein, to openthe delto-pectoral groove.

The coracoid process is identified. The clavi-pectoral fascia is incised atthe external border of the coraco-brachialis. The axillary nerve is thenidentified before subscapularisidentification.

With adequate releases, the humeralhead is dislocated into the delto-pectoral interval by abduction of thearm and progressive external rotationand extension.

Fig. 1


Primary Implantation

Humeral Head ResectionThe humeral head is now resected atthe height of the anatomical neck withthe aid of an oscillating saw – i.e. in thecartilage-covered section of the head.The resection is in the caudal direction.The Measurement and/or ResectionGuides can be used for orientation orassistance (Fig. 2a and 2b).

After the osteotomy of the humeralhead, the point of insertion of the reamer can be marked under the highest point of the resection, medial tothe bicipital groove (Fig. 3a and 3b).

Preparation of the Proximal HumerusOpen the medullary cavity with a size 7reamer by inserting the reamer into theshaft by hand or with a mallet (Fig. 4).

The medullary cavity is graduallywidened, using reamers of increasingsizes as required – sizes 9, 10.5, 12and 14. The depth of penetration is defined by the uppermost tooth. If a revision stem (long stem) is used, the additional marking on the reamershaft is used as reference.

Fig. 2a Measurement Guide 135°

Fig. 3a

Fig. 4

Fig. 3b

Fig. 2b Resection Guide


After opening the medullary canal, the proximal section of the humerus isprepared with the aid of the ModularRasp, starting with size 7 (Fig. 5).

The fin is directed towards a pointapproximately 9mm behind the bicipital groove. The proximal section of the humerus is then prepared step-wise with rasps of size 9, 10.5, 12 and14, up to the size of the previously usedreamer (Fig. 6a).

Care should be taken to ensure thatthe rasps are fully inserted into thehumerus, i.e. until the movable crosspin is visible on top and contactsboth anterior and posterior metaphysealsurfaces (no longer pivots) (Fig. 6b).

Note: Implant size is selected based onlast Rasp used that seats fully in thecavity.

The Modular Rasp handle is nowremoved and the Modular Rasp is leftin the humerus (Fig. 7).

Fig. 6a

Fig. 7

Fig. 6b

Fig. 5


Additional fixation of the modular rasp in the humerus is performed byinserting a rasp fixation screw into the Modular Rasp (Fig. 8).

Note: This is recommended if the fixation of the rasp is weak or question-able. This ensures that the rasp will notsubside with further preparation.

Mount the Milling Cutter for humeralinverse with the Cannulated Handle andstart reaming the resected humeral sur-face up to the pin in the Rasp (Fig. 9).

Note: Care should be taken to ensurethat reaming is continued as far aspossible up to the pin in the rasp.

To generate an even humeral resectionarea, use the oscillating saw for resection of the nonreamed humeralsurface area.

The plane of the humeral resection can be protected with a disk-shapedprotector (Fig. 10). Disks of 3 differentdiameters (40mm, 44mm and 48mm)are available. The pins of the lower sideof the disks are inserted at the level ofthe incision.

Fig. 8

Fig. 10

Fig. 9


Glenoid, Preparation and ImplantationTo expose the glenoid, perform a capsulotomy and resect the remainingglenoid labrum. Position a retractor at the inferior border of the glenoid, seated on the scapular pillar for thesupero-lateral approach or at the posterior part of the glenoid during the delto-pectoral approach. Use additionalretractors, positioned anterior and posterior to the glenoid. Any peripheralosteophytes should be removed torestore the natural anatomic shape ofthe glenoid.

If necessary, set the correction of versiondetermined from the preoperative CT scan on the Guiding Instrument for Glenoid Inverse (see page 12 – pre-operative planning – glenoid), identifythe optimal position, the position ofthe inferior part of the Guiding Instru-ment for Glenoid Inverse should be at the inferior end of the articularsurface, and vertical to the ground(Fig. 11). Introduce a 3mm K-wire guidepin into the guiding instrument forglenoid inverse. The laser marking onthe K-wire must disappear slightly intothe eyelet of this guiding instrument.

Remove the guiding instrument over theK-wire. The K-wire is now perpendicularto the required alignment of the arti-culating surface, which was determinedpreoperatively (Fig. 12a).

The Glenoid Reamer size S (small) andthen the Cannulated Handle are mounted on the guide wire (Fig. 12a).For a sclerotic glenoid the separate sclerotic reamer (Fig. 12b) may be usedto start the reaming process. Now reamthe glenoid in the new alignmentof the articulating surface (Fig. 13).

Fig. 11

Fig. 12a

Fig. 13

Fig. 12b

NOTE: The Zimmer ® Trabecular Metal ™ Reverse Shoulder System glenoid component assembly (i.e. base plate and glenosphere) is compatible with the PE-inlay, humeral cup, and humeral stem of the Anatomical ShoulderInverse/Reverse System. Please refer to Appendix A at the end of thisdocument for this alternate glenoid preparation and implant fixation.

If the complete surgical technique is desired, please refer to the follwing document and/or website.

Paper Copy: Zimmer® Trabecular Metal™ Reverse Shoulder System SurgicalTechnique (item number: 97-4309-003-00)

Online Copy: www.zimmer.comPlease select Medical Professional and then select surgical techniques.


Now use the reamer size L (large).

Note: The reamer size S (small) corresponds to the back surface of theAnatomical Shoulder Inverse/ReverseGlenoid Fixation. But the reamer size L(large) is needed to generate enoughclearance for the backside of theAnatomical Shoulder Inverse/ReverseGlenoid Head.

Mount the Milling Cutter for glenoidinverse with the Cannulated Handleand ream over the guide wire until thecollar is flush with the glenoid face(Fig. 14).

Place the Drill Guide for Glenoid Inverse(Fig. 15) over the 3mm K-wire, flush withglenoid surface, and bore the inferiorand the superior fixation holes. Afterdrilling the inferior hole, place the Cen-tering Pegs for Glenoid Inverse insidethe hole, then drill the superior hole.Remove the Drill Guide, the Centeringpeg and also the K-wire guiding pin.

The Anatomical Shoulder Inverse/Reverse Glenoid Fixation is available in one size for both 36mm and 40mmglenoid heads and is implanted without cement.

Positioning and Screw Fixationof the Anatomical ShoulderInverse Glenoid FixationThe Anatomical Shoulder Inverse/Reverse Glenoid Fixation is attached to the Holding Forceps for glenoid fixation. Place the glenoid fixation withthe Central Peg into the previouslydrilled hole.

Start impacting with the Impactor forGlenoid Fixation, using controlled force.Once impacted, the glenoid fixationshould seat fully on the glenoid. If not,impact until fully seated (Fig. 16).

Fig. 14

Fig. 15

Fig. 16

Note: Care should be taken to correctlyorient the superior/inferior peg position of the glenoid fixation, beforeimpacting the glenoid fixation


The Impactor is removed and the FreeHand Drill Guide for Inverse/ReverseScrews is located in the inferior glenoidfixation hole. Both inferior and superiorscrew positions allow angulations of30°. The Drill Guide for Inverse/ReverseScrews is used to set the most appropri-ate angle to ensure that each screw islocated in reliable bone stock (Fig.17).Preferential position is usually chosenby palpating the inferior and superioraspects of the scapula as well asexamining the radiographs and CTscans. The inferior hole is drilled withthe 3.3 drill for Inverse/Reverse Screws.Note: The screw lengths are lasermarked on the drill, for use with thedrill guide. Remove the drill guide.

The Inverse/Reverse Screw 4.5mm(available in lengths of 18–48mm isintroduced into the inferior hole andfully tightened with the hexagonal screwdriver. Next, prepare the superior holein the same manner as the inferior hole.

Now secure the Inverse/Reverse Screwposition by using the Inverse/ReverseLocking Screw. The locking screw isthen fastened with the Torque Wrench,until the Torque Wrench slips or audiblyclicks (Fig. 18).

Fig. 17

Fig. 18


Trial ReductionThe appropriate trial glenoid head 36 (green) or 40 (yellow) is attached to the glenoid fixation.The trial humeralcup is inserted into the rasp located in the humerus and a corresponding trial humeral PE inlay 36 (green) or 40(yellow) is then inserted into the trialhumeral cup.

Note: Three thicknesses of the humeralPE inlays are available: 0 (standard),+3mm and +6mm. In case of severebone defects or inadequate deltoid tension, a +9mm humeral cup compo-nent can be used (possible humerusheights: standard 0 (standard), +3mm,+6mm, +9mm, +12mm and +15mm).

The shoulder is then reduced andassessed for a full range of movement.

If soft tissue tension is correct, the glenoid components will not impingeon the inferior rim of the resectedhumeral head, and the shoulder jointremains stable when the arm isadducted, with no indication ofsubluxation (Fig. 19).

To change the trial Humeral PE Inlays, a lexer chisel can be used to lever theinlays from the humeral cups.

Glenosphere PlacementThe definitive Anatomical ShoulderInverse/Reverse Glenoid Head is nowunpacked. The size of the glenoid headhas been defined by the previously usedTrial Glenoid Head, 36mm or 40mm.

Note: The Anatomical Shoulder Inverse Glenoid Head has a laser mark for correct connection, this laser markmust face the acromion.

The Glenoid Head is now fitted onto theoval taper of the glenoid fixation(Fig. 20). Use three consecutive malletstrikes on the Impactor to seat the Glenoid Head the Glenosphere is now prepared.

Fig. 19

Fig. 20


Humeral PlacementRemove, if used, the optional rasp fixa-tion screw from the rasp located in the humerus. Remove the rasp with themodular rasp handle. Unpack the definitive Anatomical Shoulder HumeralStem (of the size determined by the last modular rasp used) cemented oruncemented (press-fit). Unpack theInverse Humeral Cup. The size has beendefined by the previously used trials.

The humeral implant stem (cemented oruncemented) is now placed into thestem holder of the assembled mountingblock. The inverse humeral cup is nowplaced on the humeral implant stem, inthe appropriate rotation and impactedonto the humeral implant stem with theaid of the Impactor (Fig. 21).

Implantation of the Prosthesisinto the Humeral ShaftWith the cemented prosthesis, a cementrestrictor can be inserted into thehumerus, followed by the cement in arelatively fluid consistency. The implantis now inserted into the humerus, by applying controlled force with thethumb on the humeral cup. The lateralstem fin is used as orientation. This is done until the lower side of thehumeral cup is resting on the humerus.The implant is brought into finalposition with careful blows from theImpactor Inverse (Fig. 22). If the cementprosthesis is being used, excess cementis then carefully removed. If desired, thedeltoid tension can be checked again,with the Trial Humeral PE Inlays on thehumeral cup implant. Now insert theInverse Humeral PE Inlay (with the snapin locking mechanism) with the help ofthe PE Inlay Impactor (Fig. 23).

Fig. 21

Fig. 22

Fig. 23


Reduction and ClosureThe prosthesis is then reduced and stability is checked (Fig. 24). Once thejoint space is irrigated and cleared ofdebris. A drain is left in place. Layeredclosure of the soft tissue normallyleads to an adequate range of motion,without instability.

Postoperative TreatmentAppropriate postoperative physio-therapy has begun: The arm is put into asling, but passive and active elevationto the front is allowed. Weight liftingand active elevation with the extendedelbow are not allowed for 6 weeks.

Fig. 24


From Anatomical toInverse/Reverse

Removal of the Anatomical HeadWith a Cemented Humeral Stem, remove cement from the lower side ofthe humeral head with a Lexer chisel, so that the extraction instrument can beapplied.

The Extraction Instrument is nowapplied to the humeral head and fixedwith a two-edged screw (Fig. 26).

With the aid of the Extractor Instrumentand the slide hammer weight, thehumerus head is separated from the humeral stem parallel to the lowerside of the humeral head (Fig. 26).

To remove the cement from the thread if the humeral stem is cemented, a drill jig is first inserted into the ovalcone of the humeral stem and thenused to guide the drill (Fig. 27).

Note: Care should be taken to ensurethat drilling is continued as far aspossible.

Note: Instruments are from RevisionTray.

Fig. 25

Fig. 27

Fig. 26

Fig. 30a Fig. 30b


Any remaining cement is now removedfrom the thread of the stem with theThread Reamer (Fig. 28).

The x-pin is now screwed into thehumeral stem (Fig. 29a). The x-pinguides the reamer and is essential fordirecting and fixing the Inverse Humeral Cup.

Note: Care should be taken to ensurethat the x-pin is fully screwed in and that the oval internal cone is notdamaged when this happens.

To remove the cement above the ovalcone, use the RH Reamer (Fig. 29b).Reaming is performed with the cannu-lated handle from the glenoid tray.

To prepare the humeral surface for theInverse Humeral Cup, place a Bushingfor Milling Cutter onto the humeralstem. The Bushing for Milling Cuttergets secured in the Humeral Stem withthe Screw for Bushing for Milling Cutter (Fig. 30b). If the Bushing for Milling Cutter can not be placed onto theHumeral Stem, remove bone or cementwith a Lexer chisel. Now attach the Cannulated Handle to the Milling Cutterand start reaming the Inverse/ Reversehumeral surface up to the Bushing forMilling Cutter in the Humeral Stem(Fig. 30b).

Note: Care should be taken to ensurethat reaming is continued as far aspossible up to the bushing in thehumeral stem.

If necessary for a well prepared humeral resection area, use the oscillating saw for resection of the nonreamed humeral surface area.

Note: The Bushing for Milling Cuttercomes in five different types (straight,±10° retro and ±20° retro version). To help set the bushing for the milling cutter correctly onto the humeral stem,all bushings have a mark. This linealways needs to face the lateral hole ofthe stem (Fig. 30a).

Fig. 28

Fig. 29a Fig. 29b

lateral holeof stem

mark

Fig. 31


The plane of the humeral resectionshould be protected with a disk-shaped protector (Fig. 31). Disks of 3 differentdiameters (40mm, 44mm and 48mm)are available. The pins of the lower sideof the disks are inserted at the level ofthe incision.

Glenoid, Preparation and ImplantationPlease see pages 17–20.

Humeral PlacementThe inverse humeral cup is now finallyimpacted onto the humeral implantstem with the aid of the ImpactorInverse.

Insert the snap-in mechanism Inverse/Reverse Humeral PE Inlay with the helpof the PE Inlay Impactor (Fig. 32).

To check the deltoid tension again, usethe Trial Humeral PE Inlays on theHumeral Cup Implant. To remove the Trial Humeral PE Inlay, a Lexer chisel orsimilar instrument can be used to dis-connect the Trial Humeral PE Inlay fromthe Humeral Cup Implant.

Reduction and ClosureThe prosthesis is then reduced and stability is checked (Fig. 33). Once thejoint space is irrigated and cleared ofdebris. A drain is left in place. Layeredclosure of the soft tissue normallyleads to an adequate range of motion,without instability.

Postoperative TreatmentAppropriate postoperative physio-therapy has begun: The arm is put into a sling, but passive and active elevationto the front is allowed. Weight lifting andactive elevation with the extendedelbow are not allowed for 6 weeks.

Fig. 32

Fig. 33


Anatomical ShoulderInverse/Reverse

Revision

Humeral Side

Fig. 34bFig. 34a

Fig. 35a Fig. 35b

Glenoid Side

If the Humeral PE Inlay ever has to beremoved from the Humeral Cup, slide aLexer chisel underneath the Humeral PEInlay and pry off (Fig. 34a).

Note: The Humeral PE Inlay cannot bereused after removal.

If the Humeral Cup ever has to beremoved from the Anatomical ShoulderStem, slide the Extractor Instrument forHumeral Cup between the humeralshaft and the under surface of theHumeral Cup. Firmly tap the movablepart of the instrument to loosen the Cup(Fig. 34b).

If the Glenoid Head ever has to beremoved from the Glenoid Fixation,slide the Extractor Instrument for Gle-noid Head between the back surface ofthe Glenoid Head and the front surfaceof the Glenoid Fixation. Tap the end ofthe instrument to loosen the GlenoidHead (Fig. 35a & 35b).

Anatomical ShoulderHumeral Stem Uncemented

TiAlNb Wrought AlloyISO 5832-11Uncemented

Part Number Diameter (mm) Length (mm)

01.04201.072 7 10001.04201.092 9 11001.04201.102 10.5 11001.04201.122 12 11001.04201.142 14 110

LengthA

131


Implants

Anatomical ShoulderStandard Long Stems (Revision)


01.04215.072 7 20001.04215.092 9 21001.04215.122 12 21001.04215.142 14 210

Anatomical ShoulderStandard Stem Cemented

CoCrMo Cast AlloyISO 5832-4Cemented


01.04211.072 7 10001.04211.092 9 11001.04211.122 12 11001.04211.142 14 110

Length

Diameter Diameter

STERILE R STERILE R

d


Anatomical Shoulder Inverse/ReverseGlenoid Fixation

ISO 5832-11

Part Number

01.04223.200

Inverse/Reverse Screw System

ISO 5832-3


01.04223.018 4.5 1801.04223.024 4.5 2401.04223.027 4.5 2701.04223.030 4.5 3001.04223.033 4.5 3301.04223.036 4.5 3601.04223.042 4.5 4201.04223.048 4.5 48

Anatomical Shoulder Inverse/ReverseGlenoid Head

ISO 5832-12

Part Number Diameter (mm)

01.04223.236 3601.04223.240 40

Diameter

LDiameter

STERILE R STERILE RSTERILE R


Anatomical Shoulder Inverse/Reverse Humeral Cup

ISO 5832-11

Part Number h (mm) E (mm) a Version

01.04223.100 0 0 0 0° retro 01.04223.106 0 6 0 0° retro +6

(medial offset)

01.04223.190 9 0 0 9mm 0° retro 01.04223.196 9 6 0 9mm 0° retro +6

(medial offset)

01.04223.110 0 0 +10 +10° retro 01.04223.111 0 0 –10 –10° retro 01.04223.120 0 0 +20 +20° retro 01.04223.121 0 0 –20 –20° retro

Anatomical Shoulder Inverse/ReverseHumeral PE-Inlay

ISO 5834-1/5834-2

Part Number Diameter (mm) h (mm)

01.04223.360 36 001.04223.363 36 301.04223.366 36 601.04223.400 40 001.04223.403 40 301.04223.406 40 6

h

diameter

h

E

a

STERILE R STERILE R


Anatomical ShoulderInverse/Reverse Instrument Set(complete) ZS01.04239.000

Contains the following:Anatomical Shoulder Inverse/Reverse Lid

01.00029.031

Anatomical Shoulder Inverse/Reverse Base (empty)

01.04239.010

Screws for Bushing for Milling Cutter 01.04239.560

Inverse/Reverse Locking Screw Holder 3.5mm 02.00024.121

Inverse/Reverse Torque Wrench02.00024.022

Centering Pegs for Glenoid Inverse01.04239.135

Extractor Instruments for Glenoid Head 01.04239.160

Extractor Instrument for Humeral Cup01.04239.320

Trial Humeral PE Inlays36-6 01.04239.720 36-3 01.04239.710 36-0 01.04239.700 40-6 01.04239.750 40-3 01.04239.740 40-0 01.04239.730

Instruments

Bushing for Milling Cutter –20° retro 01.04239.550+20° retro 01.04239.540–10° retro 01.04239.530+10° retro 01.04239.5200° retro 01.04239.510

Trial Glenoid Heads40 01.04239.81036 01.04239.800

Trial Humeral Cups (Set 1)+9 0° retro +6mm 01.04239.670 +9 0° retro 01.04239.660–20° retro 01.04239.650+20° retro 01.04239.640

Guiding Instrument for Glenoid Inverse 01.04239.100

Trial Humeral Cups (Set 2)–10° retro 01.04239.630+10° retro 01.04239.620 0° retro +6mm 01.04239.6100° retro 01.04239.600


All instruments

Drill for Glenoid Inverse01.04239.140

Holding Forceps for Glenoid Fixation01.04239.120

Impactor PE Inlay 01.04239.310

Impactor Inverse 01.04239.300

Anatomical Shoulder Kit Numbers:

Anatomical Shoulder Removable Head Instrument Case 1 ANSH500

Anatomical Shoulder Removable Head Instrument Case 2 ANSH600

Anatomical Shoulder Pegged Glenoid Instrument Case 3 ANSH0100

Anatomical Shoulder Revision Instrument Case 4 ANSH700

Anatomical Shoulder Keeled Glenoid Instrument Case 5 ANSH0101

Anatomical Shoulder Inverse/ReverseInstrument Case ANSH800

Anatomical Shoulder Inverse/Reverse Insert for Tray (empty)

01.04239.020

Drill Guide for Glenoid Inverse01.04239.130

Milling Cutter for Humeral Inverse primary 01.04239.400revision 01.04239.500

Milling Cutter for Glenoid Inverse 01.04239.110

Drill Guide for Inverse/Reverse Screws 01.04239.170

Impactor for Glenoid Fixation01.04239.150

Hexagonal Screw Driver02.00024.023

Drills 3.3 for Inverse/Reverse Screws 01.04239.180

Note: Standard Anatomical Shoulder Instruments are also required.

STERILE R


APPENDIX A:

Alternate Glenoid Preparationand Implant Fixation Using theZimmer® Trabecular Metal™

Reverse Shoulder System

Straight-on exposure of the glenoid isnecessary for proper reaming andcomponent insertion. If the superior-lateral approach was utilized, a forkedretractor or the Zimmer ShoulderShoehorn Retractor (Fig. 36) can beplaced inferiorly on the glenoid toretract the humeral head out of the way.If exposure is limited, re-evaluate thelevel of the humeral cut.

If the delto-pectoral approach waschosen, the proximal humerus isretracted posteriorly and inferiorly.Again if exposure is limited, re-checkthe humeral osteotomy level and ensureinferior capsular releases werethorough. Both approaches requirecircumferential exposure of the glenoidwith labral excision. Inferiorly, theglenoid must be exposed to allowpalpation of the inferior glenoid pillarand inferior positioning of the glenoidbase plate.

Note: While preparing the glenoid, theplacement of the proximal humerus andprovisional along with retractors shouldbe carefully considered. Their positionsmay allow for interference with glenos-phere seating. Exposure should allow forstraight-on engagement of the glenos-phere on the base plate taper. Consideruse of the Zimmer Shoulder ShoehornRetractor as it has been designed to aidin retracting the humeral head and othersoft tissue when placed on the posteriorside of the glenoid (Fig. 37).

Fig. 36

Fig. 37


If desired, the Glenoid Scraper can beused to clean the glenoid face of anyremaining articular cartilage or scartissue. Assemble the Base Plate DrillGuide 1 by placing the face into thehandle so that the two pieces mate androtate into position (Fig. 38). Evaluatepositioning of the base plate by placingthe Base Plate Drill Guide 1 on theglenoid face. The outer rim of Drill Guide1 is the same diameter as the baseplate. The outer rim can be rotatedrelative to the handle to check coverageof the anterior, inferior and posterioredges of the glenoid. The drill guideshould be placed so that the outer rimaligns with the inferior rim of theglenoid and is centered in theanterior/posterior direction (Fig. 39).This will place the glenosphere at theedge of the inferior glenoid bone.

Note: Inferior placement of theglenosphere is critical and will helpreduce the possibility of scapularimpingement and notching.

Load the 2.5mm Pin into a K-wire driveror Jacobs chuck. The 2.5mm Pin ismarked for the appropriate insertiondepth (Fig. 40). Insert the 2.5mm Pinthrough Drill Guide 1 until the depthmark indicated on the pin meets the topof Drill Guide 1 (Fig. 41). Release the Pinfrom the K-wire driver or Jacobs chuck,and lift Drill Guide 1 from the glenoidleaving the 2.5mm pin in place.

Fig. 39

Fig. 38

Fig. 40

Fig. 41

depthmark


The 6mm Cannulated Drill is now usedto create a pilot hole for the glenoidreamers. It is attached to theCannulated Straight Driver by sliding theDriver tabs into rounded slots of the6mm Cannulated Drill. Turn theCannulated Straight Driver to retain the6mm Cannulated Drill. Place theCannulated Drill assembly over the2.5mm Pin and drill until the housingcollar is flush to the glenoid face (Fig.42). The 6mm Cannulated Drill and the2.5mm pin are now removed.

Attach Base Plate Reamer 1 to theCannulated Straight Driver assemblyand hand ream to prepare the glenoidsurface for the back of the base plate.This is a sharp reamer and powerreaming may remove excessive bone.Ream until the reamer face iscompletely flush with the preparedsurface and the subchondral bone isexposed inferiorly (Figs. 43 & 44).

Note: If necessary, remove anyremaining prominent glenoid bone.

Attach either the 36mm or the 40mmBase Plate Reamer 2 to the CannulatedStraight Driver assembly (Fig. 45). Reamuntil the spokes are flush to thepreviously reamed face. The outercutting teeth of Base Plate Reamer 2 willream the surrounding bone to provideclearance for the glenosphere head.Once the base plate implant is in place,surface reaming is not possible.

Note: This step is necessary to ensurethe glenosphere head will lock on theGlenosphere Base Plate properly. All reasonable efforts should be madeto use the appropriate Base PlateReamer 2. The size of base plate reamercorresponds to the glenosphere headto be used.

The base plate post hole must now beprepared. The system provides threetools, a 7.5mm Drill, a 7.5mm CortexDrill and a 7.5mm Compression plug, toaid in post hole preparation based onbone quality and surgeon preference(Fig. 46). All three are used through theBase Plate Drill Guide 2 which is placedin the cavity created by the last BasePlate Reamer used.

Fig. 42

Fig. 46

Fig. 45

Fig. 43

Fig. 44

7.5mm 7.5mm 7.5mmDrill Cortex Drill Compression

Plug


Poor Bone Stock:When poor bone stock exists, use the7.5mm Cortex Drill (Fig. 47) to removeonly the first 3 to 4 mm of glenoidcortex. If a press fit of the distal end ofthe Glenosphere Base Plate post isdesired, then the preparation iscomplete. If it is deemed appropriate tocompress more bone, use the 7.5mmCompression Plug to compress thecancellous bone in the vault prior toimplant insertion.

Note: The Compression Plug should notbe used unless the 7.5mm Cortex Drill isfirst used. Otherwise there may be arisk of fracture.

Good Bone Stock: Only if there is good hard bone, use the7.5mm Drill to ream bone for the fulldepth of the post of the base plate (Fig. 48).

Note: A small drill can be used to soundfor confirming good bone quality. DrillGuide 2 has two reference marks tohelp aid in the superior/inferiorplacement of the Inverse/ReverseScrews. You may choose to makeanatomical marks for the placement ofthe Inverse/Reverse Screws.

Base Plate InsertionBefore glenoid component insertion,carefully note and mark the inferiorglenoid pillar. Place the Base Plateimplant on the Base Plate Inserter andinsert it into the preparation (Figs. 49 &50). Achieve proper orientation byaligning the grooves on the base plateto the previously placed marks oranatomic reference points forplacement of inferior and superiorscrews. The Base Plate is inserted bystriking the Base Plate Inserter until thecomponent is completely flush with theprepared surface (Fig. 51). Care shouldbe taken to avoid tipping the Base Plateduring insertion thus preventingcircumferential contact.

Screw InsertionThe 2.5mm Drill Guide is inserted intothe screw holes and oriented to preparefor screw insertion (Fig. 52).The inferiorscrew should be oriented toward theinferior border of the scapula down thepreviously identified glenoid pillar. Thesuperior screw should be orientedalong the superior border of the scapulatoward the coracoid.

Note: Do not aim the drill towards thecentral Trabecular Metal post.

Attach the 2.5mm drill to power anddrill the screw holes through the 2.5mmdrill guide and base plate at the desiredorientation (Fig. 53). The 2.5mm drillhas lines corresponding to the screwlengths available.

Fig. 47

Fig. 48

Fig. 49

Fig. 50

Fig. 51

Fig. 52

Fig. 53


Remove the drill and the drill guide.Assemble the Depth Gauge and insertinto the screw holes to aid in selectingthe proper screw length (Figs. 54 & 55).

Note: Screws are available in 18-48mmlengths.

Inverse/Reverse Screws are adjustablewithin a possible 30° arc (Fig. 56) andthus can readily be angled to achievegood bone purchase. The screws areinserted through the inferior andsuperior screw holes with theHexagonal Screw Driver, making suregood bone purchase is achieved (Fig.57). If good bone purchase is notachieved, the screws should beremoved and prepared at a new angle.The screws are then converted to a fixedangle by placing the locking screw capson the Inverse/Reverse screws usingthe Inverse/Reverse Torque Wrench andLocking Screw Holder.

To do this, the locking screws areplaced onto the tip of theInverse/Reverse Torque Wrench and theLocking Screw Holder is gently slid overthe locking screws to secure them (Fig.58). The locking screws are placed overthe heads of the Inverse/ReverseScrews and the Locking Screw Holder isslid back (Fig. 59). Turn the lockingscrews in place until the Torque Wrenchslips or an audible click is heard.

Note: The locking screws only engagein one orientation. The wider opening(Fig. 60) must be pointing toward thescrew. Additionally, to avoid mis-threading, the screwdriver shaft shouldbe perpendicular to the base plate toproperly screw down the locking screw.Failure to slide back the Locking ScrewHolder can block locking screwinsertion.

Fig. 60

Fig. 58

Fig. 59

Fig. 55

Fig. 54

Fig. 56

Locking screw cap

Fig. 57


Base plate RemovalShould the Base Plate ever need to beremoved, the Locking Screws andInverse/Reverse Screws are removed byutilizing the Hexagonal Screwdriver (Fig.61). If removal is intraoperative, theBase Plate can be removed by leveringwith an osteotome. If removal ispostoperative, standard osteotomes arefirst used to disassociate as much ofthe bone ingrowth area as possiblefrom the implant. Each bolt of the BasePlate Remover is threaded into the BasePlate using the Hexagonal Screwdriver.This is done by moving the barrel overto one side, threading one bolt into ascrew hole in the base plate, thenmoving the barrel to the other side andinserting the second bolt into the otherscrew hole (Fig. 62). Thread down thebolts until the instrument is securelyattached.

A Standard Slaphammer should bescrewed into the body of the Base PlateRemover (Fig. 63). Repeatedly impactuntil the Base Plate has been removed.

Fig. 64

Fig. 61

Fig. 63

Fig. 62

If not placed previously, attach a TrialGlenosphere Head to the Base Plate byhand or with the Glenosphere Helmet(Fig. 64).


Implant Insertion

Glenosphere AssemblyThe glenosphere is typically inserted priorto humeral component final seating tomaximize exposure of the glenoid andease of insertion. Ensure all soft tissue isremoved around the base plate to allowthe glenosphere to completely seat.

Assemble the Glenosphere HelmetInserter by threading the dualtaper/spacer impactor into either the36mm (green) or the 40mm (yellow)glenosphere helmet (Fig. 64). Insert theappropriate diameter glenosphere intothe helmet by sliding it into the helmet sothat the glenosphere is held in place bythe body of the helmet and the tabs restsecurely underneath the glenosphere(Figs. 65 & 66). Wipe the Base Plate taperclean of all fluids. Place the ZimmerShoulder Shoehorn Retractor on theposterior side of the glenoid to aid inretracting the humerus and other softtissue (Fig. 67). When approaching thebase plate, a finger can be placed on topof the glenosphere to help guide and feelthe glenosphere slide over the taper intoposition. Note: While engaging theglenosphere, it is important to monitorthe position of the proximal humerus andprovisional along with retractors sincethey could interfere with glenosphereplacement. Once the glenosphere isseated evenly and circumferentially, useyour free hand to press firmly on theglenosphere to secure it to the baseplate. Keeping a finger on theglenosphere, remove the GlenosphereHelmet pulling the instrument away in theSAME DIRECTION used to insert theglenosphere (i.e. If an anterior approachwas used to insert the glenosphere,remove the instrument by pulling it fromthe anterior direction). This will helpminimize changes to the glenosphereplacement on the base plate and damageto the glenosphere helmet itself.

Fig. 67

Fig. 66

Fig. 64

Fig. 65

dual taper / spacer impactor

36mm 40mm

Fig. 70


Note: If unable to visually confirm aneven, circumferential engagement ofthe glenosphere to the base plate,consider the use of a fluoroscope to aidin the confirmation. Seating of theglenosphere to the base plate can beexamined in the axillary view or in aview parallel to glenoid version. Themedial rim of the glenosphere shouldbe parallel to the face of the base plate(Fig. 68).

Assemble Glenosphere Impactor Headto the Impactor Handle and place theGlenosphere Impactor Head on theGlenosphere. Strike the GlenosphereImpactor Head with 3 firm mallet strikesto engage the glenosphere on the baseplate (Fig. 69). Pull on the glenosphereto verify the taper is locked. Reconfirmthe circumferential engagement withthe base plate. Reduce the joint andconfirm and confirm range of motion.

Glenosphere RemovalShould it become necessary to removethe glenosphere, the GlenosphereDistractor can be used. Assemble theGlenosphere Distractor. Wedge the fintip between the superior glenoid boneand the underside of the glenosphere(Fig. 70). There must be good contact onthese two surfaces for disengagementto occur. Pull the Glenosphere Distractortrigger until it fires. The glenospherehead should be loose enough to gentlyremove by hand. If not, repeat the stepmaking sure there is contact betweenthe distractor tip, the glenoid bonesurface and the glenosphere head.Reduce the joint and confirm range of motion.

Fig. 69

Fig. 68 Please refer to page 21 for humeral placement.

Contact your Zimmer representative or visit us at www.zimmer.com

97-4223-002-00 5ML Printed in the USA ©2006, 2007, 2008 Zimmer, Inc.

+H124974223002001/$060301C07V

Please refer to the package insertsfor complete product information,including contraindications, warnings,precautions and adverse effects.

Documents

Anatomical Shoulder Inverse/Reverse Systemfaculty.washington.edu/alexbert/Shoulder/Surgery/... · 4 Anatomical ShoulderTM Inverse/Reverse Surgical Technique Foreword Total shoulder