OFFSET / LENGTH / VERSION MODULAR PRIMARY HIP STEM SYSTEMS THAT PROVIDE OPTIONS COMPARISON AND BUYER S GUIDE OVERVIEW

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1 OFFSET / LENGTH / VERSION MODULAR PRIMARY HIP STEM SYSTEMS THAT PROVIDE OPTIONS COMPARISON AND BUYER S GUIDE the freedom of an active ifestye OVERVIEW The need to ensure proper baance and tension of the soft tissues that surround the hip joint is a high priority and is intrinsic to the utimate goa of restoring the patient to as norma a gait as possibe. It is necessary to ensure that the eg ength on the operative side is equa to the contraatera side. This need is key to patient satisfaction. Even more important is overa stabiity of the Hip Joint, which is heaviy dependant on the abiity to position both the Acetabuar and Femora Components to accommodate the anatomy of each patient. The abiity to achieve the idea soft tissue tension, eg ength and neck version for each patient ies primariy with the surgeon and pre-operative panning is essentia to meet individua needs. The technoogy of moduarity has been used to hep surgeons add to their armamentarium, to aid them to better address the needs issues for each patient to have the best outcome possibe. The purpose of this paper is to examine and provide an objective comparison of the currenty avaiabe Primary Moduar Impant Systems with variabe abiity to achieve optima tissue tension, eg ength and position of the neck of the femora prosthesis. Our focus in this paper is on impants used for primary Tota Hip Arthropasty (THA) that have empoyed moduarity to provide intraoperative adjustments. SYSTEM FEATURES FOR CONSIDERATION AND COMPARISON Currenty, we contrast and compare six Primary Moduar Hip Stem systems avaiabe in the U.S. designed with differing degrees of adjustabiity to address Neck Offset, Vertica Height and the Version of the Neck. We are defining these features of the impants as foows: NECK OFFSET: The distance as measured from the horizonta center of the Femora Head to the center of the Femora Cana. It is the distance between the Center of Rotation of a zero ba and the Vertica Midine of the stem component. VERTICAL HEIGHT: We have chosen the term VERTICAL HEIGHT (VH) in order to define Neck Height as it appies to the Femora Neck Component. This is the distance between the Center of Rotation of a zero ba and the top of the Metaphysea portion of the Hip Stem (generay at the point of the Cacar cut). VERSION: This is defined as the ange at which the Femora Neck is positioned with regard to the M/L pane of the Femur. For the purposes of defining a femora hip repacement impant, it is the position of the Head/Neck as presented in the proxima femur, above the bone. Version Adjustabiity Independent Adjustment of Height and Offset 1

2 The 6 Moduar Systems GRADING THE SIX MODULAR SYSTEMS The foowing is a quick grading grid of seven key criteria for Moduar Hip Stem Systems for Primary Indications. Note: A six systems have Moduar Necks that add or subtract to Version, Vertica Height and Neck Offset. For the purpose of Comparison we have used ony one Head Length, +0 for a systems. System 1 S&N EMPERION System WRIGHT PROFEMUR System 2 DePuy S-ROM System 4 APEX SURGICAL Grading Moduar Hip Stems Systems by Offset, Length and Version Versatiity Grading System: Yes = 1 Point; No = 0 Points; 1 Point for Every Choice System # Neck is a Moduar Component A O ffsets Avaiabe on A Stems Necks Choices per Stem Size O ffset Change without Changing Stem O ffset Change without Changing VH Version is Version Change without Stem Remova Tota Points Note: The produc t information provided is based on iterature avaiabe from each respective manufacturer at the time of this pubication, October Manufacturers often change features and make additions to product ines over time, which may render the information provided inaccurate. THE DESIGN FEATURES OF THE SYSTEMS VARY SIGNIFICANTLY Each of the prosthesis designs has features, which are intended to provide a method to adjust Neck Offset, Vertica Height and Version. These features vary significanty between systems and the differences do have an affect on the function of the devices. This paper discusses and compares these systems based on what are beieved to be key points and criteria when considering the use of a moduar system. System 5 EXACTECH M-SERIES System 6 MIPRO US INC. M-COR 2

3 KEY QUESTIONS Can an in vivo impanted stem have its Neck Offset and Vertica Height adjusted easiy and economicay if need be? Can the Neck Offset and Vertica Height be triaed with the Stem Modue in Pace? Basicay, there are two types of Moduar Hip Stem Systems: Systems 1 and 2: The Stem has a fixed Neck. The Neck Offset and Vertica Height is determined and cannot be adjusted once the Stem is impanted. n A change of Offset and Vertica Height, beyond the capabiity of the moduar Femora Head requires remova of an impanted Stem (which means that it is wasted) and repacement with a new Stem. n In vivo triaing for Neck Offset and Vertica Height (with the Stem impanted) is imited to tria Femora Heads ony. Systems, 4, 5 and 6: The Neck is a separate Moduar Component that is fixed onto the in vivo Impanted Stem. The Neck Offset and Vertica Height is sti adjustabe after stem impantation The Stem Modue is initiay impanted without the Neck Modue. n The Neck Modue, which has the Neck Offset and Vertica Height buit in, is then ocked onto the Stem Modue. In these Systems there sti is an option to tria a Neck Modue on the actua Stem to ensure that the Neck Offset and Vertica Height (and Version) are optima. No component needs to be wasted. Does Offset Adjustment aso Ater Vertica Height? Neck Offset of a prosthesis can be increased or decreased by changing the Stem/Neck Ange. However, this method wi aways change the Vertica Height and ater Leg Length. System has a seection of Moduar Neck Components. n Standard Neck has an ange of 15 degrees. n The VV (Varus/Vagus) Neck Modue can be used to increase offset with pacement in its Varus position (127 degrees) and decrease offset with pacement in its Vagus position (142 degrees). n Because the Neck Offset is changed by changing the Neck Ange, Vertica Height is aso affected. u Varus Ange reduces Vertica Height/Leg Length u Vagus Ange increases Vertica Height/Leg Length u Often, this can be compensated for by using a onger or shorter Femora Head, but onger sometimes means a coar, which reduces range of motion, and shorter is not aways avaiabe. The other Moduar Systems (4, 5, and 6) extend the Neck Offset with a Longer Neck whie sti maintaining the same Neck Ange. n Neck Offset is adjusted without affecting Vertica Height and Vertica Height is adjusted without affecting Neck Offset. Is Version Seection and Easiy Adjusted In Vivo? i.e. coud the need to change Version, after the Stem or Neck Modue is opened, ead to the necessity to open a second Stem or Neck Modue? Again, there are basicay, two types of Moduar Hip Stem Systems: Systems 1 and 2 have a Stem that has a fixed Neck: Neck Version seection is. Neck Version is determined when the Stem is impanted based on the triaing phase of the procedure. n Fina Neck Version is determined when the Stem is positioned within the Femora Cana. u These Stems have aggressive Dista Futes for rotationa Stabiity, which make it a chaenge to position the Stem at the exact Neck Version indicated with the Tria Neck/Stem. n A change of Version means removing the impanted Stem and rotationay repositioning it. This has been proven difficut to do.

4 Systems, 4, 5 and 6 have a Neck Modue that is a separate Component. The Stem modue can be impanted into the Femora Cana without concern of the Neck Version, which wi be determined when the Neck Modue is inserted. However, not a Stem Systems with a Moduar Neck work the same way or provide the same capabiity, such as Version Seection. System does not offer Version Seection as it has Moduar Necks that are ocked into the Stem by use of a rectanguar taper with rounded corners. n These Neck Modues have the Version Ange buit in imiting the amount of Neck Version that can be obtained: u The Standard Neck is straight and Version is determined by the position of the Stem within the Bone. u The A/R 8 and A/R 15 Necks provide the abiity to position for eight degrees of Anteversion or eight and fifteen degrees of Retroversion ony without the abiity to gain or reduce offset. u The A/R VV Neck provides the abiity to position for four degrees of Anteversion or Retroversion ony without the abiity to gain or reduce offset. System 4 does not offer Version Seection. n The Neck Modue is secured onto the Stem Modue using a non-taper interface via a Pin and three Hoes on the adjacent surfaces. n The Neutra Neck Modue utiizes the Center Hoe of the underside that wi interface with the Pin, setting the Neck in Neutra Version. n The Version Neck Modue has two Hoes in the underside, each 1 degrees from the centerine. n Aignment can be set, imited to ony 1 degrees of Anteversion or 1 degrees of retroversion. n Because Version is dependent on the Neck Modue, with this system a change in Version coud ead to the wasting of a Neck Modue. System 5 and System 6 have Neck Modues that engage with the Stem Modue and offer Version. n System 5 Neck Modue engages into the Metaphysea Segment of the Stem Assemby and is secured with a Locking Screw. n System 6 Neck Modue has a -degree Morse Taper that engages with the Stem to create a Cod Wed. How Many Neck Offsets Does the System Provide and can Every Neck Offset be used on Every Size Stem? Do a Neck options aow Version Seection? System 1 and System 2: Choice of six Neck Offsets (with +0 Femora A Neck options do offer Version Seection. Neck Offset is imited by stem size: Maximum Neck Offset System : 4mm 7mm 50mm Stem Diameter 9mm 11mm 1-15mm 11, 17-19mm 1-15mm 17-19mm Choice of six Neck Offsets (with +0 Femora n 2mm, 4mm, 6mm, 49mm, 52mm, 56mm Every Neck Option avaiabe can be used on any size Stem. However a Neck options have imited Version. System 4: Choice of seven Neck Offsets (with +0 Femora n 5mm, 7.5mm,, 42.5mm,, 47.5mm, 50mm Every Neck Option avaiabe can be used on any size Stem. However, Version Seection is not with any of the Neck Options System 5: Choice of two Neck Offsets (with +0 Femora n 6mm and 41mm 4

5 Every Neck Option avaiabe can be used on any size Stem Version is avaiabe on a Neck options System 6: Choice of five Neck Offsets (with +0 Femora n 1, 5, 9, 4, and 47mm Every Neck Option can be used on any size Stem Version is avaiabe on a Neck options Strength and endurance is essentia and moduarity, with its many benefits, has paced greater emphasis on the need for assurance that the components wi not break and that the connections between the components are secure and wi not cause an unacceptabe eve of wear debris. Has the technoogy that secures the moduar components been proven in Orthopedic Impants? Systems 1, 2, and 6: The Modues are secured using a three degree Morse Type Taper with a round cross-section. Tapers such as these have been used since 1984 to interock moduar components. System : The Neck is secured in a pocket utiizing a curved corner, rectanguar crosssection taper ock. System 4: The Dua Press connection has a hoe in the Stem and a Mating Peg on the Neck with parae (not tapered) sides at their interface. A Pin on the Stem interocks with a hoe in the Neck, presumaby to provide additiona resistance to rotation. This technoogy is reativey new to Orthopedic impants as of System 5: The Neck Modue engages with the hoe in the Metaphysea Segment, which engages into a separate Dista Segment. A Locking Screw is used to secure these components. What testing has been performed and has it been done independenty or in-house? Strength and Endurance testing information must be provided by the manufacturer aowing the surgeon to evauate the facts. System 6: We have access to the testing data for this system performed by an independent ab (Surgica and Orthopaedic Research Laboratories, Sydney). n A tests surpassed the requirements of ISO 7206 (1992). In a situations the stem and neck/stem taper junction remained totay in tact without oosening, rotation or excess wear. n In addition to the minimum stem requirements set by ISO, further testing of the Femora Neck was performed to determine the endurance imit of the worstcase component. u The neck was found to survive a oad of 6.1 times body weight in a strength/ direction fatigue situation to the runout condition of 10 miion cyces. u No oosening or rotation of the components resuted. u As part of this endurance testing, a static bending test of the neck component was aso performed. The resuts show that the component began to yied at approximatey 15.8 times body weight. u This test was terminated when the neck impinged on the top face of the stem at a oad of 17.5 times body weight (17.5x 74kg or 16 pounds). u Ony minimum wear debris was generated. Can the components be disassembed? The manufacturer shoud be abe to demonstrate the tested and proven method for remova, which in most of these systems requires breaking a taper ock. There have been reports of difficuty: n System 2: The taper between the Stem and the Proxima Seeve modues have been know to be difficut to reverse and the Stem has been known to be difficut to remove. n System : We have knowedge that the Moduar Neck has been difficut to remove from the Stem. In one case, an attempt to disengage and remove the Neck Modue resuted in remova of the entire assemby in one piece requiring repacement of the entire Stem when changing the Neck Modue was the intended procedure. 5

6 SUMMARY Moduar Femora Stem components hep the tota hip repacement speciaists to meet the intrinsic goas of reestabishment of eg ength and offset for the comfort, satisfaction and function of their patients. The option to independenty seect neck version is proven to hep to estabish optima position of the Femora Stem as we as the Acetabuar component to provide greater joint stabiity. Comparing the six moduar Femora Stem systems there are cear design differences, which then refects on their abiity to address the key issues of independent adjustabiity of eg ength, offset and version. This is worthy of consideration when making the decision as to which moduar stem system wi do the most to hep address these key issues by offering the most options and the highest eve of safety. The key questions to ask are therefore: 1. Does the system aow adjustment of Neck Offset without affecting Vertica Height and vice versa? 2. Does the chosen Femora Stem system ock in your seection of Neck Offset and Vertica Height requiring a compete exchange of Stem to make changes?. Does the position of the impanted Femora Stem ock in Version, requiring a compete remova of the Stem in order to reposition the Version? 4. Does the system aow of Version seection? 5. Which system provides the most options? 6. Is the testing data provided independenty and correcty coected to assure endurance and resistance to mechanica faiure? CONCLUSIONS The outcomes and patient benefits that resut from moduarity are too good to pass up and shoud be used in many patients that require Tota Hip Arthropasty. There is itte correation to the size of the manufacturer and the innovative devices that are designed and produced. History has shown that it is the smaer companies that innovate most to hep the speciaist address key issues. The M-COR Moduar Hip System has been designed and produced by Mipro US, Inc. and we beieve that this is the device to consider when a moduar devices are hed up to the scrutiny. It is possibe with the M-COR system to independenty adjust Neck Length, Offset and Version with an aready in vivo impanted Stem: Moduar Stem and Neck Assembe fuy in situ Largest range of necks Independent adjustment of: n Version n Offset n Height Neck exchange easy Neck exchange independent of Stem Independenty tested As it meets or exceeds every criterion that we have discussed, we strongy recommend the consideration and usage of the M-COR Moduar Hip System for patients that are candidates for cementess Femora Stem fixation. 6

7 Exhibit A System 1 Neck Offset Vertica Height* (mm) Stem Size Version Options S&N EMPERION 4mm 7mm 50mm , 15 1, 15 17, 19 17, 19 System 2 Neck Offset Vertica Height* (mm) Stem Size Version Options DePuy S-ROM 4mm 7mm 50mm , 15 1, 15 17, 19 17, 19 System Neck System Vertica Offset Version Height Options WRIGHT PROFEMUR 1mm 2mm 4mm 6mm 6mm 7mm 49mm 49mm 52mm 54mm 55mm 56mm 6mm 42mm 8mm 6mm 4mm 5mm Neutra ony 4 degree ony Neutra ony 8 degree ony 4 degree ony 15 degree ony Neutra ony 4 degree ony Neutra ony Neutra ony 4 degree ony 15 degree ony 8 degree ony System 4 Neck Offset Vertica Height* (mm) Version Options APEX SURGICAL 5mm 7.5mm 42.5mm 47.5mm 47.5mm 50mm 5mm 27.5mm 5mm System 5 Neck Offset Vertica Height* (mm) Version Options EXACTECH M-SERIES 6mm 6mm 6mm 41mm 41mm mm 8mm 48mm mm 8mm System 6 Neck Offset Vertica Height* (mm) Version Options MIPRO US, INC. M-COR 1mm 5mm 9mm 4mm 47mm 24mm 24,26, 26,28, 26,28,0,2mm 28,0,2,4mm 7

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