comprehensive shoulder system Design Rationale Knees Hips Extremities Cement and Accessories PMI TEchnology
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INTRODUCTION The Comprehensive Shoulder System is an evolutionary design based on the successful clinical heritage of the Bio-Modular Shoulder System, Biomet s flagship shoulder for the past 20 years. The Comprehensive Shoulder System s unique engineering, industry-leading biomaterials, versatile offerings and easy-to-use instrumentation offer surgeons an ideal option for hemi and total shoulder arthroplasty and provide for patient-specific selection when choosing an implant. Distinctive features, including the industry s only reduced length humeral stems, the Versa-Dial humeral head that allows for true variable offset and the modular hybrid glenoid with optional ArCom polyethylene or Regenerex Porous Titanium Construct central pegs, make the Comprehensive Shoulder System stand apart from the competition. comprehensive humeral stems Construct and Coating Stems are made from titanium alloy (per ASTM F-136) with titanium PPS Porous Plasma Spray on the proximal body. While titanium alloy provides a modulus of elasticity closer to that of bone than most other materials commonly used for humeral stems (i.e. cobalt chrome alloy), the plasma sprayed porous coating has a clinically proven role in facilitating bone ingrowth for increased stem fixation. 1 Diameter Stem sizes are designated in 1mm diameter increments, ranging from 4 to 20mm for standard and mini stems, and 4 to 15mm for revision stems. The proximal geometry of each standard stem is the same as the corresponding size mini stem. The size designation of the stem is determined by measuring the diameter of the corresponding standard stem at a point 100mm down from the bottom of the proximal body box. However, this point is theoretical on the mini stem because the stem is shorter than 100mm. Lengths Stem offerings include mini ( 83mm), standard ( 122mm) and revision ( 194mm) lengths. Stem length can be found by measuring from the theoretical intersection of the stem axis and trunnion axis to the distal tip of the stem. 83mm 122mm 194mm Mini Standard Revision Geometry The stems feature a 45 degree anatomic neck angle and are tapered distally to provide a tight wedge-like fit in the humeral shaft. The box geometry of the proximal body and medial throat transition to the shaft fills the proximal humerus, with the purpose of increasing the fixation of the stem and resisting rotation in situ. Glenoid Access The stem has a reverse Morse taper to facilitate unobstructed preparation of the face of the glenoid for total shoulder arthroplasty. In the case where it may become necessary to convert a hemi-arthroplasty to a total shoulder arthroplasty, the surgeon can remove the humeral head and still gain access to the glenoid.
Additional Features The proximal body of the stem has a threaded hole at the bottom of its Morse taper and a second hole on its superior surface for instrumentation attachments. To conserve proximal bone and facilitate revision, should this become necessary, the primary stems have no fins. Also, these stems have a diminished collar, thereby allowing insertion of an osteotome between the bone and the stem, and are polished distally to minimize bone ongrowth. Revision Stems The revision stem shares many design features of the standard and mini length stems, though there are some notable exceptions. It has a fin with two suture holes to facilitate tuberosity reconstruction in complex fracture cases. Also, the porous coating length is significantly longer to aid bone ingrowth when the proximal bone quality is not optimal. Finally, the revision stem has a blasted finish distally to aid fixation in bone or cement. VERSA-DIAL HUMERAL HEADS Construct The articulating surface of the head is made of cast cobalt chrome (per ASTM F-75). Cobalt chrome alloy is the accepted industry standard for surfaces articulating with polyethylene as well as bone. Unnecessary weight was removed by eliminating material from inside the humeral head. The taper adaptor is made from titanium alloy. The small male taper (which inserts into the humeral stem) has a threaded hole through its end for use in instrumentation applications. The entire adaptor is cannulated to allow air to escape from inside the head during impaction of the adaptor into the head. Sizes Heads are available in 17 sizes, ranging from 38 to 58mm in diameter and 18 to 27mm in height. The sizing is broken down into six articular surface diameter (ASD) families with two to four head height (HH) options in each family. The resulting diameter of curvature is based on the ASD and HH dimensions. The heads form a bell curve of height options with respect to the diameter families, with the historically most popular ASD sizes having the most head height options. Head Geometry Three key dimensions determine the geometry of the head: head height (HH),* articular surface diameter (ASD) and diameter of curvature (DC). Head Height (HH)* Diameter of Curvature (DC) ASD x HH* x DC Articular Surface Diameter (ASD) Minimized Gap Care was taken to ensure the gap between the bottom of the humeral head and resected surface of the humerus was minimized. This included tightening tolerances that played a role in the gap dimension, as well as adding a skirt to the underside of the humeral head so the implant head would be able to sit over and surround the collar of the humeral stem. The blend radius between the underside of the humeral head and the articulating surface was maximized to create the effect of a soft implant that would be less destructive to the rotator cuff. Compatibility The head is designed to provide a modular humeral head that is compatible with the primary and revision stems of the Comprehensive Shoulder System, as well as the Bio-Modular Shoulder. ** Comprehensive Standard Taper Adaptor Bio-Modular Standard Taper Adaptor *HH dimension includes a 0.5mm gap between head and stem. **Bio-Modular Shoulder requires separate taper adaptor.
0.5mm Offset 3.5mm Offset 4.5mm Offset Glenoid Stability Shear loads are applied to the face of the glenoid as the humeral head translates across the articulating surface. In order to add additional stability against shear forces, design considerations identified multiple fixation methods for this element, and a modular central peg option was chosen to accommodate these fixation methods. A central boss was included in the design to allow for the central peg options, as well as to provide additional shear resistance if the glenoid is utilized without a central peg. Axial Pull-out Variable Offset The head has a variable offset that allows the surgeon to set an infinite amount of offset between 0.5 and 4.5mm. Variable offset is achieved by utilizing a two-piece design including the humeral head and a taper adaptor. The head has a female taper, the axis of which is offset from the axis of the head. 800 700 600 Shear (Inferior/Superior) Shear (Anterior/Posterior) 636 578 The adaptor has two male tapers (one mates with the head, the other mates with the stem), which are offset from each other. In this manner, the head can be dialed in to achieve 0.5mm of offset (position A), 4.5mm of offset (position E), or any amount of offset in between. lbf 500 400 300 200 209 383 483 248 438 460 303 MODULAR HYBRID GLENOIDS Clinically Proven Design The modular hybrid glenoid was designed based on the clinically proven Bio-Modular pegged glenoid. It features a base in three sizes (small, medium and large), three outer pegs for cemented fixation and two central peg options for additional fixation. 100 0 No Central Peg 1 Regenerex Central Peg 1 Polyethylene Central Peg 1 Optional Central Pegs The central fixation methods involve the use of an interference fit. The first option is an ArCom polyethylene compression fit central peg, featuring fins that interfere with a prepared hole in the center of the glenoid and requires the use of bone cement at the base of the central peg. The second option, a Regenerex porous titanium peg, provides for additional biologic fixation and bone ingrowth, and does not require bone cement. Modular Hybrid Glenoid ArCom Polyethylene Compression Fit Central Peg Regenerex Porous Titanium Central Peg
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Reference 1. Data on file at Biomet. Bench test results not necessarily indicative of clinical performance. Comprehensive, Bio-Modular, Versa-Dial, ArCom, Regenerex and PPS are trademarks of Biomet Manufacturing Corp. This material is intended for the sole use and benefit of the Biomet sales force and physicians. It is not to be redistributed, duplicated or disclosed without the express written consent of Biomet. For product information, including indications, contraindications, warnings, precautions and potential adverse effects, see the package insert and Biomet s website. P.O. Box 587, Warsaw, IN 46581-0587 800.348.9500 ext. 1501 2007 Biomet Orthopedics, Inc. www.biomet.com Form No. BOI0030.0 REV093007