HELICA Hybrids - Veterinary Instrumentation

Chapter 8JOINT REPLACEMENT 8HELICA CEMENTLESSHIP SYSTEMModular, cementless,screw-in total hipreplacement.Now available withimproved three partstem. (TPS)The Helica System of Total Hip Replacement is unique in a number ofrespects.Most cementless systems rely on a ‘press fit’ for at least one implantcomponent. Creation of the site for the component is critical andtechnically demanding or the component will not lock into position. Inaddition, press fitcomponents arevulnerable untilosseous integrationdevelops over severalweeks (if it happens atall). In man this is lessof an issue in that thepatient can strictlycontrol the stressplaced on the new hip.We have much lesscontrol over our caninepatients during thiscritical phase.Both Helica components screw into position giving post operative securityduring the phase of osseous integration. The cup is not only fixed veryrigidly but can even be re-positioned intra-operatively, should it berequired, without losing any security. The Helica cup may be used with allother leading brands of stems to create a hybrid system with maximum cupsecurity.The stem is a short prosthesis located entirely in the proximal femur. Onlythe articular surface is removed during implantation retaining the maximumbone stock. The new Three Part Stem (TPS) ensures more accuratepositioning of the stem in addition to an increased surface area for loaddispersement. A choice of flanges is available to suit individual femoralneck size.Only the articular surface of thefemoral head is removed,retaining the maximum amountof bone stock to support thefemoral prosthesis, whichscrews into place. Althoughperhaps counter intuitive thesmall stem in the proximal femurloads at least as well as longstemmed prostheses.The outer surface of theacetabular cup is threaded forrapid screw-in insertion.Repositioning of cupsintraoperatively is straightforward. Revision cups forother systems are available.Both femoral and acetabular components screw into position allowingimmediate loading. The surface finish of the titanium componentsencourages rapid osteointegration. Flexibility is achieved by:• 5 Stem sizes• 5 Neck lengths• 3 Flanges for the femoral neck• 5 Acetabular Cup sizesOnce the implantation sites have been prepared the implants self tapinto position.8The surface of both acetabular shell and femoral stem are treated tomaximise osteointegration of implants.Advantages• Short surgery time• Minimally invasive• Cementless technique• Screw-in implants• Immediately loadable• Cost effective223

8 JOINT REPLACEMENTHELICA Surgical TechniquePre-operative assessment and planninggives the predicted size of cup, stem andhead/ neck.The acetabulum is prepared by reamingwith progressively larger and largerreamers finishing with the predicted size.Using the insertion T grip and alignmentaid the threaded shell for theacetabulum is positioned ready forinsertion. The threads on the shell areself tapping and are firmly screwed intoposition. After assessment the shellmay be re-positioned if necessary.The extension pin is added to thechosen stem to ensure correctalignment of the stem in thefemoral neck. The stem is slowlyscrewed into position until the tipexits the lateral cortex. The finethread at the neck of the stemshould sit below the resectionline. The milling tool will removeexcess bone to leave theresection line at right angles tothe stem.The axis is determined in part by eye butaided by a goniometer. The axis isestablished initially by a small drill which isprogressively opened using larger and largerdrills.The resection of the femoral headis made just distal to the bonecartilageinterface. The resectionis made perpendicular to thefemoral stem implant axis. Theface of the osteotomy will bemilled at a later stage to ensurethat the bed for the femoralcomponent flange is alignedcorrectly. The osteotomy isfacilitated by use of the Helicahohman to lift the femoral head.The milling tool prepares the bone surface for theflangewhich sits on and spreads the load onto thefemoral neck. The new stem design ensures thatthe flange will always sit squarely on the milledarea. The flange is fitted and locked in position bya locking ring.The cup inlay is a click fit into theacetabular shell. Insertion isaccomplished using an insertion tool.The rim of the inlay should sit flushwith the shell margin.After trialling, the appropriatefemoral head is locked ontothe femoral neck. Theinterface is a very securemorse taper. Hybrid headsare available to fit other hipsystems to allow the use ofthe Helica cup when revisingother system cup failures.The selectedhead is fitted.The femoral component must be inserted along the axis of the femoralneck. It is important to spend time establishing the correct axis.A CCD angle of 145 to 147 degrees is desirable.Much thought and care should be taken when placing the initial 2.0 or2.5mm drill hole which should exit the lateral cortex. Drills of increasingsize are used to open up the femoral neck. Each drill should exit the lateralcortex. The final drill for the femoral neck will be the pilot drill for thepredicted femoral component.Correct positioning of the implantsis confirmed by radiography.This surgical guide is included to give anover view of the technique. Surgeonscontemplating use of the Helica systemmust attend a recognised training course. Afuller illustrated guide is included.224

www.vetinst.comJOINT REPLACEMENT 8HELICA HybridsThe stability of the Helica Cup is such that it may be used in conjuctionwith press fit cups from other systems either as a revision or as a primaryprocedure.Helica Heads are available in various lengths which interface with Stemsfor the Kyon and BFX Systems. These Heads fit standard Helica cups. Thetray of Acetabular Instruments may be purchased separately afterattending an approved training course.Ancillary Helica InstrumentationMeyerdingThree instruments, not included in the standardsets, make osteotomy and alignment of thefemoral stem significantly easier and arerecommended. The Meyerding is a verypowerful hand held retractor.The Helica Hohman has a dished profile and fine teeth along its leadingedge to lift the femoral head and neck up from the incision for osteotomy.The goniometer helps the surgeon to establish the correct axis for thefemoral stem at an angle of 145 to 147 degrees.HELICA ANCILLARY INSTRUMENTSHohman001038 Helica Hohman Large £65.00001037 Helica Hohman Medium £65.00001036 Helica Hohman Small £65.00HE-GONIO Helica Goniometer £62.50150019 Meyerding Retractor £57.50Helica Total Hip InstrumentationHelica Total Hip Implants (2012 Version)ACETABULAR CUPSHE-HC1-T24 Helica 24mm Acetabular Cup £445.00HE-HC1-T26 Helica 26mm Acetabular Cup £445.00HE-HC1-T28 Helica 28mm Acetabular Cup £445.00HE-HC1-T30 Helica 30mm Acetabular Cup £445.00HE-HC1-T32 Helica 32mm Acetabular Cup £445.00TPS STEMS (2012 VERSION)HE-HS3-T0831 TPS Helica Stem 8mm x 31mm (2012 Version) £335.00HE-HS3-T0932 TPS Helica Stem 9mm x 32mm (2012 Version) £335.00HE-HS3-T1035 TPS Helica Stem 10mm x 35mm(2012 Version) £335.00HE-HS3-T1137 TPS Helica Stem 11mm x 37mm(2012 Version) £335.00HE-HS3-T1239 TPS Helica Stem 12mm x 39mm(2012 Version) £335.00TPS FLANGE (2012 VERSION)HE-HF3-T18.5 TPS Helica Flange 18.5mm (inc 1 Locking Nut) £55.00HE-HF3-T20 TPS Helica Flange 20.0mm (inc 1 Locking Nut) £55.00HE-HF3-T22 TPS Helica Flange 21.5mm (inc 1 Locking Nut) £55.00TPS LOCKING NUT (2012 VERSION)HE-HN3-T08 TPS Helica Locking Nut (for replacement) £18.00FEMORAL HEADSHE-FH1-18S Helica 18mm Femoral Head - Short £125.00HE-FH1-18M Helica 18mm Femoral Head - Medium £125.00HE-FH1-18L Helica 18mm Femoral Head - Long £125.00HE-FH1-18XL Helica 18mm Femoral Head - Extra Long £185.00HE-FH1-18XXL Helica 18mm Femoral Head - XX Long £185.00INLAYSHE-AL1-P24 Helica 24mm Inlay £90.00HE-AL1-P26 Helica 26mm Inlay £90.00HE-AL1-P28 Helica 28mm Inlay £90.00HE-AL1-P30 Helica 30mm Inlay £90.00HE-AL1-P32 Helica 32mm Inlay £90.00HYBRID REVISION IMPLANTSHE-FHB-18-0HE-FHB-18-3HE-FHB-18-6HE-FHK-18XSHE-FHK-18SHE-FHK-18MHE-FHK-18LHE-FHK-18XLHelica Hybrid 18mm Femoral HeadBiometric Shank + 0 £165.00Helica Hybrid 18mm Femoral HeadBiometric Shank + 3 £165.00Helica Hybrid 18mm Femoral HeadBiometric Shank + 6 £165.00Helica Hybrid 18mm Femoral HeadKyon Extra Short £165.00Helica Hybrid 18mm Femoral HeadKyon Short £165.00Helica Hybrid 18mm Femoral HeadKyon Medium £165.00Helica Hybrid 18mm Femoral HeadKyon Long £165.00Helica Hybrid 18mm Femoral HeadKyon Extra Long £165.00Helica Total Hip Stem Implants (Original Version)These Stems are the original design to be used in conjunction with theoriginal instrumentation.HELICA TOTAL HIP INSTRUMENTATIONHE-KIT Helica Instrument Kit (2012 Version) £5,750.00STEMSHE-HS1-T0826 Helica Stem 8mm x 26mm £360.00HE-HS1-T0928 Helica Stem 9mm x 28mm £360.00HE-HS1-T1028 Helica Stem 10mm x 28mm £360.00HE-HS1-T1132 Helica Stem 11mm x 32mm £360.00HE-HS1-T1232 Helica Stem 12mm x 32mm £360.00225

8 JOINT REPLACEMENTHip Fixation and Navigation DeviceConstruction is of titanium and high-strength aluminium, for easy cleaningand maintenance.When not in use, the table can be disassembled for storage.The two halves of the table feature slots for all components, clippingtogether to for secure storage between uses.During Total Hip Replacement procedure, correct placement of theacetabular cup is essential. Navigation Devices have been around forsome time, often home-made.This Navigation Device gently positions the patient in the correct position,and includes an orientation guide to ensure the correct inclination andretroversion angles are maintained.The blue handle allows easy rotation of the table to aid comfortablepositioning, reducing the risk of stress on the spine.HIP FIXATION AND NAVIGATION DEVICEHE-HFN-KS-01 Hip Fixation and Navigation Device £1,575.00226

www.vetinst.comJOINT REPLACEMENT 8Veterinary Instrumentation Modular Hip System(Cemented)Femoral ProsthesisTwo stems are available whichare identical distally. Supplied sterile.FEMORAL PROSTHESIS150200 Large Stem (Sterile) £250.00150201 Small Stem (Sterile) £250.00150300 Long Ball (Sterile) £135.00150301 Short Ball (Sterile) £135.00HDTHPDVD Hamish Denny Total Hip DVD £40.00Acetabular CupsPhotography: Hamish DennyThe modular format gives four different femur combinations. Two stemsizes are available. The taper neck is the same on both. Two ball optionsare available, the ball diameter is 15mm in both cases. The “short neck”ball when fitted to the standard taper neck gives a short necked prosthesisand the “long neck” ball gives a long necked prosthesis. When combinedwith the two acetabular cups a total of 8 combinations are possible. Themost common combination is a small stem and long neck ball together witha small acetabular cup.The surgeon most familiar with the system is Hamish Denny FRCVS, whohelped develop the system and has performed over 200 procedures. Healso produced the instructional DVD which is available on free loan. This isnot a ‘high tech’ system which requires a mass of dedicatedinstrumentation and jigs. It is a simple, well proven system which assumesthat the surgeon has the knowledge and expertise to complete theprocedure.Two sizes are available. The internal diameter is the same, as all the headsof the femoral components are 15mm in diameter. The only differencebetween the cups is the wall thickness and therefore the outside diameter.All cups are marked with stainless rings to establish cup position onradiographs. Cups have very deep grooves on the external diameter toprovide good cement keying. Supplied sterile.ACETABULAR CUPS150402 Medium Acetabular Cup (Sterile) £145.00150401 Small Acetabular Cup (Sterile) £145.00Hatt SpoonCombination Stem size Neck Acetabular cup1 Small Stem Short Small2 Small Stem Long Small3 Small Stem Short Medium4 Small Stem Long Medium5 Large Stem Short Small6 Large Stem Long Small7 Large Stem Short Medium8 Large Stem Long MediumAn alternative to the disarticulator in large dogs. The edge of the spoon issharp. As used by Martin Olmstead. The VI version has a narrower shaftand a fibre handle for ease of use.HATT SPOON001092 Hatt Spoon 230mm Scoop 17mm x 30mm £62.50227

8 JOINT REPLACEMENTFemoral RaspAcetabular SkidThe aim of the Femoral Rasp is to produce a hole the same shape as thestem of the femoral prosthesis plus a margin for the bone cement. TheFemoral Rasp can create seating for both stems in that both stems have asimilar profile distally and differ only in the proximal area. To create aseating for the large stem simply make a deeper hole.FEMORAL RASP150005 Femoral Rasp £485.00Femoral ReamerA double-ended instrument useful in the dislocation of the femoral headprior to excision. Also useful in “helping” the head of the femoral prosthesisinto the acetabular cup.ACETABULAR SKID6200/05 Acetabular Skid £85.00Femoral Prosthesis PusherUse in conjunction with the femoral rasp to open up the proximal femur.‘T’ handle format with an overall length of 270mm. Use 6mm for the distalportion and 8mm proximally.FEMORAL REAMER150003 Femoral Reamer 6mm 270mm £235.00150004 Femoral Reamer 8mm 270mm £235.00Cylindrical RaspThis instrument fits both small and large femoral prostheses and allows thesurgeon to position the stem and apply pressure as the cement sets.FEMORAL PROSTHESIS PUSHER161602B Femoral Prosthesis Pusher £185.00Acetabular Cup PositionerUse to widen opening in femur. Available in 6mm and 8mm diameter.CYLINDRICAL RASP150008 Cylindrical Rasp 6mm diameter £235.00150009 Cylindrical Rasp 8mm diameter £235.00Acetabular ReamersPhotography: Hamish DennyPhotography: Hamish DennyThis instrument holds the acetabular cup in position as the cement sets.ACETABULAR CUP POSITIONER161602A Acetabular Cup Positioner £185.00Meyerding RetractorEach Reamer is designed to produce a prepared bed for each cup.The Reamer shaft is 1 /4” (6.3mm) to fit air or electric rechargeable drills.The multi-bladed style has a much longer life than the cheese grater type.Good soft tissue retraction is essential. The Reamer head can bere-sharpened on an exchange basis.ACETABULAR REAMERS150012 Small Acetabular Reamer £235.00150010 Medium Acetabular Reamer £235.00A heavy duty retractor for use around the hip.Much favoured by Martin Olmstead.MEYERDING RETRACTOR150019 Meyerding Retractor 16mm £57.50228

www.vetinst.comJOINT REPLACEMENT 8Hohman Retractor 20mm Wide with Short Kinked TipThis Hohman is designedfor femoral neckretraction for THR.Please see page 66 forfurther informationHOHMAN RETRACTOR 20MM WIDE WITH SHORT KINKED TIP001039 Hohman 20mm Wide with Short Kinked Tip £65.00Heygroves Femur Grasping ForcepsPowerful clamps to lock onto the femoral shaft.Used to rotate the femoral head outwards for excision.HEYGROVES FEMUR GRASPING FORCEPS150017 Heygroves Femur Grasping Forceps 10" £150.00Lewin Femur Grasping ForcepsBone CementDePuy CMW Bone CementDesigned for total hip replacement.CMW is the industry standard.Various options are available. Alsouseful in stabilisation of vertebralfractures/luxations.CMW1 is a medium/high viscositycement for digital applicationCMW2 is a rapid set cementsuitable for the acetabular cup via digital application.CMW3 is a more fluid cement which is more appropriate for the femoralcomponent. It is usually applied via a 50ml syringe.CMW cement comes impregnated with Gentamycin which minimises postoperative infection, the worst complication of the procedure.CMW BONE CEMENT160506 CMW1 no Gentamycin 40g £80.00160500 CMW1 with Gentamycin 20g £100.00160501 CMW2 with Gentamycin 20g £100.00160503 CMW3 with Gentamycin 20g £100.00160504 CMW3 with Gentamycin 40g £120.00Veterinary Instrumentation Bone CementThe curvature and multiple teeth of these forceps matchalmost exactly the profile of the large dog femur.Another Martin Olmstead favourite.LEWIN FEMUR GRASPING FORCEPS150018 Lewin Femur Grasping Forceps £95.00Total Hip Replacement KitThe Total Hip Replacement kit is a cost effective solution saving over 10%when compared to the component costs. The set also includes one of eachimplant.Our Total Hip Replacement kit includes the following:INSTRUMENTSCylindrical Rasp 6mmCylindrical Rasp 8mmFemoral RaspFemoral Reamer 8mmFemoral Reamer 6mmAcetabular Reamer SmallAcetabular Reamer MediumStem PositionerCup PositionerLewin Bone Holding ForcepsMeyerding Retractors x 2Trial Stem SmallTrial Stem LargeTrial Cup SmallTrial Cup MediumTOTAL HIP REPLACEMENT KITIMPLANTSStem SmallStem LargeShort Neck BallLong Neck BallCup SmallCup MediumTraining DVDStainless CasePlease note that the kit does notinclude bone cement.150001 Total Hip Replacement Kit £3,650.00VETERINARY INSTRUMENTATION BONE CEMENT VACUUM MIXBC1 High Viscosity 40g £55.00BC1G High Viscosity 40g with Gentamycin £65.00BC3G Low Viscosity (syringe) 40g with Gentamycin £65.00CVAC Mixing System (unit) £65.00CGUN Application Gun £595.00BOWLSET Set of 3 Mixing Bowls and Spatula £14.00SPATDISP Disposable Spatula - Non-sterile (100 units) £5.75SYRINGE 50ml Catheter Mount Syringe. Sterile £4.45SPATULA Autoclavable Plastic Mixing Spatula £6.25Antibiotic Impregnated Polymethacrylate Beads(AIPMMA)Management of chronic local infections may benefit from the insertion ofantibiotic impregnated polymethacrylate(AIPMMA) beads. The Beads aremanufactured from sterile bone cement with the addition of appropriateantibiotic.Indications include osteomyelitis and abcessation in the rabbit.Veterinary Instrumentation offers two Kits for the preparation of AIPMMABeads. Both Kits contain sufficient material for approximately 100 sterileBeads. Store unused beads in sterile containers for maximum shelf life.Full instructions are included.ANTIBIOTIC IMPREGNATED POLYMETHACRYLATE BEADS (AIPMMA)BC1GKIT AIPMMA Bead Kit with Gentamycin £75.00BC1KIT AIPMMA Bead Kit. No Antibiotic £70.00229

8 JOINT REPLACEMENTArthrex Cue SystemGelpis retract periarticular tissues.Assistant maintains valgus and internalrotation allowing CUE instrument to beplaced perpendicular to the articularsurfaces of the humeral condyle (MHC)and medial coronoid process (MCP).Ulna ImplantMedial compartment disease in dogs is a painful degenerative conditionwhich is difficult to treat. Total Elbow Replacement is not asstraightforward as Total Hip.The advent of the Arthrex CUE System brings an alternative, lessinvasive, treatment option.The System consists of humeral and ulnar components in 2 sizes, plus asmall range of specialised instruments for implantation.A Step by Step Guide and Brochure are available online or can berequested by calling 0845 130 9596.Centre the appropriate size Ulna DrillGuide on the MCP, flush to the articularsurface, and place a beath pin throughthe Ulna Drill Guide to exit the caudalridge of the ulna. When the beath pin isproperly placed, use the Ulna Drill(reamer) to create the ulnar socket.Surgeons who wish to use the CUE System must first attend a CUETraining Course. These will be advertised on our website, and surgeonsinterested in attending should e-mail info@vetinst.com to register theirinterest.CUE Surgical TechniqueA summary of the surgical procedure supplied by Arthrex follows. A fullversion of this can be supplied free of charge from VeterinaryInstrumentation. Either call 0845 130 9596 or visit our websitewww.vetinst.com.Remove the beath pin, lavage and usethe Ulna Trial to check proper reamingof the ulnar socket.Proceed to place Humerus Implant before final placement of UlnaImplantHumerus ImplantApproach is medial either with tenotomyor with epicondylar osteotomy isselected. See full guide for moreinformation.Place the appropriate sized HumerusDrill Guide on the humeral articularsurface so that it most fully covers thehumeral lesion, making sure it is flushwith the articular surface and sagittallyaligned. When the drill guide isoptimally positioned, drill the beath pinsthrough the guide and at least 15mminto the MHC, keeping the drill guidefirm and flush with the articular surface.230

www.vetinst.comJOINT REPLACEMENT 8Cut the beath pins as flush as possibleto the guide. Remove the Humerus Drillguide and insert the Drill Stop over thebeath pins.After placing Humerus Implant, placethe Ulna Implant in the Ulna ImplantHolder. Make sure ridges andradiographic marker are facing out andimplant it into the ulnar socket. Fullyseat with the Ulna Tamp if necessary.Place the Humeral Drill (reamer) in theHumerus Drill Stop and over the beathpins. Keeping the Humerus Drillpressed firm and flush against thearticular surface, use the reamer to fullyream the first humeral socket, then flipthe reamer and guide to fully ream thesecond humeral socket.Arthrex Cue System ImplantsPlace the Humerus Implant in theHumerus implant Holder so the bonyingrowth surface is facing out andimplant into the humeral sockets.Now complete insertion of the Ulna ImplantUse the Humerus tamp to fully seat theHumerus Implant.ARTHREX CUE SYSTEM IMPLANTSVAR-7005-L Canine Uni-compartmental Elbow Ulnar Large £165.00VAR-7005-M Canine Uni-compartmental Elbow Ulnar Medium £165.00VAR-7000-L Canine Uni-compartmental Elbow Humeral Large £590.00VAR-7000-M Canine Uni-compartmental Elbow Humeral Medium £590.00Arthrex Cue System EquipmentARTHREX CUE SYSTEM EQUIPMENTCUESET1 Vet CUE Set with Instrument Case £4,495.00CUESET2 Vet CUE Set without Instrument Case £3,795.00VAR-7001-L Template Humerus CUE Large £195.00VAR-7001-M Template Humerus CUE Medium £185.00VAR-7002-L Trial Humerus CUE Large £275.00VAR-7002-M Trial Humerus CUE Medium £275.00VAR-7003-L Implant Inserter Hum CUE Large £105.00VAR-7003-M Implant Inserter Hum CUE Medium £105.00VAR-7004 Tamp Humerus CUE £195.00VAR-7006-L Trial Ulna CUE Large £105.00VAR-7006-M Trial Ulna CUE Medium £105.00VAR-7007-L Implant Inserter Ulna CUE Large £50.00VAR-7007-M Implant Inserter Ulna CUE Medium £50.00VAR-7011-L Drill Humerus CUE Large £435.00VAR-7011-M Drill Humerus CUE Medium £435.00VAR-7012-L Drill Stop Humerus CUE Large £245.00VAR-7012-M Drill Stop Humerus CUE Medium £245.00VAR-7014-L Drill Ulna CUE Large £375.00VAR-7014-M Drill Ulna CUE Medium £375.00VAR-7015-L Guide Ulna CUE Large £105.00VAR-7015-M Guide Ulna CUE Medium £105.00VAR-7016 Tamp Ulna CUE £185.00VAR-7020C Vet CUE Instrument Case £700.00BRCUE Arthrex CUE Literature £FOC231

8 JOINT REPLACEMENTWORK IN PROGRESSSeveral joint replacement systems are under development which may beof interest. Some details are included here. Surgeons who are interested inbeing kept informed or take part in trials are invited to e-mailjohn@vetinst.com or david@vetinst.com.ELBOW‘Sirius’ Total Elbow ReplacementInitial clinical cases have been very encouraging and John has nowperformed 13 clinical procedures (February 2013). Individuals interested inbecoming involved should contact:-STIFLEsath@liverpool.ac.ukwww.liv.ac.uk/sathGenuSys Total Knee Replacement‘PatentsPending’The Sirius System is an unlinked TER incorporating a cemented CobaltChrome humeral prosthesis and a screwed Titanium radio/ ulnar tray. Thebearing surface is made from Ultra High Molecular Weight Polyethylene.(UHMW-PE)John Innes and the Small Animal Teaching Hospital at Liverpool Universityhave been collaborating with designers and manufacturers to produce asystem which offers:• Instrumentation to accurately identify elbow flexion-extension axis(locates on axis of humeral shaft and surface of trochlea)• Gap between humeral forks for passage of radio-ulnar implant, tooptimise ROM• Conservative bone cuts to maintain stress field on distal humerus andenhance long-term fixation (by minimising stress shielding)• All cuts are instrumented (no free-hand cutting) and reference from oneflexion-extension axis marker• Radio-ulnar cutter relies upon widely available TPLO reciprocating saw• Radio-ulnar bearing is snap-fitted to stemless, screw-fixed titanium plateproviding an internal plate fixation to the semilunar notch of the ulna toguard against fracture• Hydroxyapatite coating of the titanium plate for bony ingrowth for longtermstability• Small radial difference between TER articular surfaces to enable somejoint laxity• Universal (non-handed) implants existing in small, medium and large tocover wide range of patient size.GenuSys is an unconstrained, uncementedstifle replacement system developed by thelate Volker Hach. GenuSys is a 3component system giving maximum range ofmovement. The metal components aremanufactured from Titanium coated CobaltChrome with the Tibial Inlays being UHMW-PE.There are four sizes each one of which hasa choice of tibial inlays to suit the availablenatural constraints.30 dogs have been implanted thus far.232