taperloc : Spanning the generations surgical technique

Transcription

1 taperloc : Spanning the generations surgical technique

2 taperloc hip System...simply the best the taperloc hip system unites the benefits of: excellent clinical results Tapered Geometry Enhances Proximal Offloading and Bone Preservation a tapered geometry The Taperloc stem is collarless to superior materials allow for self-seating of the implant and manufacturing between the lateral and medial cortices of methods the femoral canal. The tapered portion of the stem provides a wedge effect in the enhanced medullary canal producing a fi t instead performance of a fi t and fi ll (Figure 1). This provides and reliability rotational and axial loading with a proven 5, 9 11 lower incidence of thigh pain. The Flexibility of Titanium TAPERLOC HIP SYSTEM The Taperloc stem is designed after the European philosophy of a fl at tapered wedge. By combining excellent clinical success and durability over the last 20 years, the Taperloc hip continues to deliver consistent, reproducible results. Figure 1 Flat Wedge & IM Rod Alloy Provides Natural Load Transfer and Tissue Strength Titanium plays a critical role in implant performance because of its excellent biocompatibility and a low modulus of elasticity that closely resembles that of bone. The fl exibility of the titanium allows for an additional avenue of stress transfer through KEY DESIGN FEATURES: the femur/implant interface that results in a femur which sustains load and preserves Flat tapered wedge geometry Largest group of patients: cortical density. Titanium alloy Ti-6AL-4V 12-year follow-up / 99.6% survivorship The Precision of Modern Digital 50% of stem is circumferentially plasma spray of 4,750 hips 6 Manufacturing Rotational stability Youngest group of patients: Recent developments in 3-dimensional Offset option 13-years follow-up / 98% survivorship solid modeling technologies allow for accurate Simple and accurate Exact of 100 hips with 100% follow-up / Instrumentation Average age: 37 years 10 interpretation of complex implant geometries. Net forgings produced by this 3-dimensional Oldest group of patients: 2 11 years follow-up / 100% survivorship CAD-CAM technology provide the most of 92 hips / Average age: 84.5 years 7 precise fit possible for the implant.

3 Circumferential Plasma Spray Promotes Better Initial Fixation and a More Complete Seal Biomet s circumferential plasma spray porous coating is designed for optimal fi xation. The non-interconnected pores act to create a seal from particulate debris migration. This construct may reduce femoral 3, 4, 13 osteolysis and improve long-term fi xation. Biomet s proprietary plasma spray application is Above is a SEM photograph at 100x unique in that only the titanium alloy powder used magnification showing plasma spray to create the coating is heated, while the implant s porous coating. substrate is retained at near ambient temperatures. Application of the plasma spray porous coating to the substrate of the implant at a low temperature helps preserve up to 90% of the mechanical strength of the implant (Figure 2). 1, 2 During the plasma spray process, randomly shaped particles are injected through a plasma flame and flattened upon impact with the substrate. The resulting surface is rough on a microand macro-level, in contrast to the smooth surfaces of a beaded implant. This unique feature of surface roughness allows the implant to scrape bone into the pores during implantation. In addition, random particle dimensions result in a varied pore size distribution. Smaller pores are important for initial fixation as they promote early osseo integration thus preventing early micromotion. Larger pores require a longer time to fill in and provide for long-term fixation with continued bone in-growth. This pore in-growth is important for stress transfer at Fatigue Strength (ksi) at 10 7 Cycles later stages. Studies have shown that rough titanium has been found to have a good propensity for encouraging adhesion of osteoblasts. 11, 12 Biomet s porous coating offers.5mm to.75mm press fit per side on the porous coated area. Sintered or Diffusion Bonded Ti and Ti Alloy Plasma Sprayed Sintered or Diffusion Bonded Range of values determined Range of values reported Co-Cr Alloy Plasma Sprayed Figure 2 Effect of the porous coating method on fatigue strength. 8 POROUS COATING VS. OSTEOLYSIS Author Reference Hip Implant System Years Followed Osteolysis Evans and DeLee Submitted for Publication Bi-Metric (Biomet) 5 10 years 0.0% Mauerhan, et al. J. Arthroplasty, 1997 Integral (Biomet) 5 8 years 0.0% McLaughlin JBJS Taperloc (Biomet) years 6.0% Head, et al. Orthopedics, 1999 Mallory-Head (Biomet) 11 years avg. 0.0% Rothman Orthopedics, 1994 Taperloc (Biomet) 7 years 3.0% Bourne, et al. Hip Society (March), 2001 Mallory-Head (Biomet) years 0.0% Multi-Center Study Biomet Clinical Report, 1994 Taperloc, Mallory-Head 5 years 0.4% Bi-Metric, Integral (Biomet) Capello, McClain Trans. Int l Sym., 1992 Omnifit (Osteonics) 2 6 years 44.7% Heekin, et al. JBJS, 1993 PCA (Howmedica) 5 7 years 18.0% Woolson, Maloney J. Arthroplasty, 1992 Harris/Galante (Zimmer) 3.5 yrs. avg. follow-up 22.0% Kim, et al. Orthop. Trans, PCA (Howmedica) 2 7 years 37.0% Kim, et al. Orthop. Trans, AML (DePuy) 2 7 years 55.8% Smith, Harris CORR, 1995 Harris/Galante (Zimmer) 4.5 yrs. avg. follow-up 31.0% Engh Presentation, 1992 AML (DePuy) 7.5 yrs. avg. follow-up 28.0% Engh Presentation, 2001 AML (DePuy) 13.9 yrs. follow-up 40.0% 1

4 Offsets: Reproducing femoral offset is recognized as an important feature of any total hip system. The Taperloc system offers two offset features for each primary stem size, standard and lateralized (Figures 3 & 4). Availability of a lateral offset design allows the surgeon to enhance stability without lengthening the leg. This allows for restoration of normal hip biomechanics. The capability of increasing the offset of the Taperloc stem by 7.8mm is achieved via a straight horizontal shift of the trunion and lengthening of the taper. FLAP OFF PG. 1 (INSIDE OF) Figure 3 Regular Offset Figure 4 Lateral Offset

5 FLAP OFF PG. 1 (BACK OF)

6 taperloc System/ exact instrumentation experience the exact hip instrumentation provides for versatility, flexibility and simplicity. INSTRUMENTATION With the Taperloc Hip System, only two trays are needed for implantation: the Exact General I and the Taperloc System Specifi c tray. Streamlined and accurate system specifi c trays provide for the ultimate in O.R. effi ciency while the recognizable color-coding (Taperloc system specifi c is green) identifi es the instrumentation specifi c to the femoral component selected. KEY COMPONENTS OF THE EXACT INSTRUMENTATION ARE: A Starter Reamer allows for the initial opening of the femoral canal. The Offset Chisel provides a direct view for initial opening of the femoral canal. Incrementally sized Magnetic Neck Trunions in standard and lateralized offsets offer accurate intraoperative biomechanical adjustment during trial reduction. Standard is gold and lateralized is black. The Femoral Inserter screws into the implant to give the implant version control upon insertion into the femur. The Taperloc Neck Resection Guide offers the versatility of medial and vertical radius reference points from the greater and lesser trochanter respectively. A convenient trochanter stop assists in marking the level of measurement. The following Exact Hip Instrumentation cases are needed to implant the Taperloc : General Case 1 Taperloc Broaches General Case II (Extraction) Open only if needed 2

7 A Broach Handle provides solid engagement with a quick, easy trigger locking mechanism that affords a clear view and a rapid release. A large impaction plate provides for solid driving contact. Broaches are fully toothed to provide the effi cient removal of cancellous bone to contour a pocket for the implant. These newly designed broaches are created utilizing the same data set used to produce the implant. Included is an improved cutting tooth pattern that is nitrided to prolong the life of the cutting edges. X-RAY TEMPLATES: PREOPERATIVE PLANNING The new Exact Template system offers a precise mode for implant sizing and preoperative evaluation of anatomic offset. Vertical and medial scales correspond to the resection guide to aid in leg length restoration. The templates are designed to match the color-coded instrument case for ease of identification and offer a table for quick offset references. Preoperative x-ray with new Taperloc Hip Template Taperloc Hip Template 3

8 the taperloc hip surgical technique the taperloc femoral component combines unmatched clinical success with the new innovative design of exact instruments to provide accurate and reproducible implantation. PATIENT POSITIONING AND SURGICAL APPROACH The goal of the surgical approach is to establish adequate visualization of the anatomy so that the entire surgical area is exposed. The patient should be placed in a full lateral position secured with positioning devices to ensure complete patient stability. An anterolateral approach via a lateral curvilinear incision is recommended (Figs. 1 & 2). FEMORAL NECK RESECTION The Exact Taperloc Femoral Resection Guide may be used to mark the neck resection level for an accurate cut. It utilizes key reference points off of the lesser and greater trochanters which correspond to the measurements on the Exact Templates. For example: When templating the x-rays, note the measurement on the vertical and medial scales that line up with the greater and lesser trochanters. Place the resection guide on the femur and line up the vertical scale with the greater trochanter. If utilizing the greater trochanter stop, pre-set it to the closest mark noted during templating. With the trochanteric stop resting on the greater trochanter, the medial markings should correspond to your preoperative planning. For example, if you measured +7 on the template, then place the trochanteric stop at the +5mm mark, erring on the side of preserving bone. Once the appropriate level of resection has been determined, proceed with cutting the femoral neck to allow for re-creation of the appropriate femoral neck length and offset (Fig. 3). Fig. 1 Fig. 3 Fig. 2 4

9 ACCESSING THE FEMORAL CANAL The Exact Offset Chisel is used to determine the orientation of the femoral canal and access the lateral section of the proximal femur. This helps to clear a channel laterally to accept the starter reamer without interference from the dense bone surrounding the trochanter. The design of the offset chisel assures adequate visualization to allow enough lateralization of the femoral canal to avoid varus positioning of the component (Fig. 4). A single starter reamer on a T-handle may be used to initiate the opening into the distal femoral canal to a level appropriate to the size component templated on the preoperative x-rays (Fig. 5). Fig. 4 CONTOURING THE STEM ENVELOPE After opening the canal, a Taperloc broach is used to contour the proximal stem envelope. Attach the broach handle to the broach by pulling back on the trigger to engage the broach. Begin the broaching process with the smallest Taperloc broach. Orientation of the broach should take into account the medial/ lateral and anterior/posterior position of the medullary canal. Progressively increase the broach size to enlarge the envelope until the broach engages the medial and lateral cortex and can not be advanced deeper or until the templated implant size is reached. Use care with insertion and removal of each broach to avoid excessive rotation and preserve the version of the femoral envelope (Fig. 6). The modularity of the broaches allow for rapid sequential broaching and the ability to accurately trial directly off of the broaches using the new magnetic neck trunions. Fig. 5 PLANING THE FEMUR Planing a collarless implant is at the surgeon s discretion. With the fi nal broach fully seated, remove the broach handle. Place the retractable calcar planer over the short post of the broach and machine the femoral neck for optimal implant contact (Fig. 7). The calcar planer is specially designed to work in conjunction with the short broach post to prevent metal-to-metal wear of the post. Fig. 6 Fig. 7 5

10 the taperloc hip surgical technique TRIAL REDUCTION To perform the trial reduction with the indwelling broach, attach the Exact Taperloc magnetic neck trials, standard or lateralized, onto the broach post. These trunions are color coded to represent offset. The gold trunion indicates standard offset while the black represents lateralized offset. The Exact Magnetic Trunions are sized to correspond to the fi nal broach, and the stem size is clearly marked on the top of the trunion (Fig. 8). Once the appropriate trunion is in place, select the trial femoral head of desired diameter and neck length. Reduce the hip Fig. 8 and evaluate the joint for soft tissue tension, anterior and posterior stability, and stability in the sleep position. If any additional adjustments to neck length and/or offset are needed they can be completed at this time (Fig. 9). Fig. 9 STEM INSERTION Once the trial reduction is considered stable, remove the broach from the femoral canal and attach the implant to the threaded femoral inserter (Fig. 10). The femoral inserter handle assists in controlling rotation of the implant and enables the implant to be inserted into the femoral envelope with the proper amount of anteversion. Care should be taken to orient the implant parallel to the prepared envelope, matching the appropriate amount of anteversion that was determined from the broaching step. The stem should slide distally into the canal without much resistance until the implant engages the lateral and medial wall of the prepared canal. Gently tap to seat the prosthesis. Remove the inserter when the implant is fully seated. A trial head component can be placed on the femoral implant neck trunion for an additional trial reduction or the selected modular femoral head can be fi rmly impacted onto the clean dry taper (Fig. 11). Fig. 10 This brochure demonstrates the surgical technique of Jeffery McLaughlin, M.D. Biomet as the manufacturer of this device, does not practice medicine and does not recommend this or any other surgical technique for use on a specifi c patient. The surgeon who performs any implant procedure is responsible for determining and utilizing the appropriate techniques for implanting the prosthesis in each individual patient. Biomet is not responsible for selection of the appropriate surgical technique to be utilized for an individual patient. Fig. 11 6

11 HEAD OPTIONS -5mm -3mm Std. -6mm -3mm Std. +3mm +6mm +9mm +12mm -3mm Std. -5mm -3mm Std. +3mm +6mm the taperloc stem grows incrementally with each stem 7.5mm 9.0mm 10.0mm 11.0mm 12.5mm 13.5mm 15.0mm 17.5mm 20.0mm 22.5mm Available in both standard and lateral offset options. size. The medial curvature remains constant for each size and grows outward laterally. 7

12 taperloc offset and ordering information STANDARD TAPERLOC POROUS PRIMARY Size Stem Neck Horizontal Offset Vertical Offset Neck Length Length Angle -6-3 STD STD STD mm 135mm mm 137mm mm 140mm mm 142mm mm 145mm mm 147mm mm 150mm mm 155mm mm 160mm mm 165mm mm 170mm LATERALIZED TAPERLOC POROUS PRIMARY Size Stem Neck Horizontal Offset Vertical Offset Neck Length Length Angle -6-3 STD STD STD mm 135mm mm 137mm mm 140mm mm 142mm mm 145mm mm 147mm mm 150mm mm 155mm mm 160mm mm 165mm mm 170mm

13 TAPERLOC FEMORAL COMPONENT Stem Stem Implant Implant Rasp/Prov. Size Length Standard Lateralized Neck Angle mm mm mm mm mm mm mm mm mm mm mm Taperloc Standard and Lateralized Stems TAPERLOC MAGNETIC NECK TRUNIONS Standard (Gold) Lateralized (Black) Sizes Part No. Sizes Part No Exact Taperloc Template Taperloc Specific Cases: Exact Taperloc Broach Case Exact General Case I Exact General Case II

14 REFERENCES 1. Bourne, R.B.; et al.: Ingrowth Surfaces: Plasma Spray Coating to Titanium Alloy Hip Replacements. Clin. Orthop., 298: 37 46, Collier, J.P.; Head, W.C.; Koeneman, J.; et al.: Symposium: Porous Coating Methods: The Pros and Cons. Contemporary Orthop., 27(3): , Emerson, R.H.; Sanders, R.B.; Head, W.C.; Higgins, L.: Effect of Circumferential Plasma-spray Porous Coating on the Rate of Femoral Osteolysis After Total Hip Arthroplasty. J. Bone Joint Surg., 81-A: , Sept Head, W.C.: Mallory-Head Porous Press-Fit Primary Hip Replacement. Presented at the Tenth Annual International Symposium: New Developments in Total Joint Reconstruction, Lake Tahoe, Nevada, June 14 16, Hozack, W.; Rothman, R.; Eng, K.; Mesa, J.: Primary Cementless Hip Arthroplasty with a Titanium Plasma Sprayed Prosthesis. CORR, 33(3): , Dec Hozack, W.: Ten Year Experience with a Wedge-Fit Stem. Crucial Decisions in Total Joint Replacement and Sports Medicine, Bermuda, Keisu, Kjell; Orozco, F.; Sharkey, P.; et al.: Primary Cementless Total Hip Arthroplasty in Octogenarians: Two to Eleven Year Follow-up. J. Bone Joint Surg., 83-A: , Leudeman, R.: The Effect of a Plasma Sprayed Porous Ti-Alloy Coating on the Rotation Beam Fatigue Strength of Co-Cr-Mo Alloy. Biomet Technical Report, McLaughlin, J.R.; Lee, K.R.: Total Hip Arthroplasty with an Uncemented Femoral Component. J. Bone Joint Surg., 79-B: , McLaughlin, J.R.: Plasma Sprayed Porous-Coated Total Hip Arthroplasty: A 13-year Survivorship Analysis in Patients Age 50+ and Under. Presented at the 63rd AAOS, San Francisco, Sharkey, P.F.; et al.: Initial Stability of a Collarless Wedge-Shaped Prosthesis in the Femoral Canal. Seminars in Arthroplasty, 1(1): 87 90, July Symposium: Porous Coating Methods: The Pros and Cons. Contemporary Orthop., 27(3): , Sept Tanzer, M.; et al.: The Progression of Femoral Cortical Osteolysis in Association with Total Hip Arthroplasty without Cements. J. Bone Joint Surg., 74-A: March, Taperloc is a registered trademark of Biomet, Inc. Exact is a trademark of Biomet, Inc. P.O. Box 587, Warsaw, IN Biomet Orthopedics, Inc. All Rights Reserved web site: biomet@biomet.com Form No. Y-BMT-745/022802/K