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D'Antonio J.A.,Greater Pittsburgh Orthopaedics Association | Capello W.N.,Indiana University | Ramakrishnan R.,Stryker Orthopaedics
Clinical Orthopaedics and Related Research | Year: 2012

Background Compared with conventional polyethylene, first-generation highly cross-linked polyethylenes have low wear, but controversy exists regarding their reduced mechanical strength and/or retained free radicals. Secondgeneration highly cross-linked polyethylenes have been developed to reduce wear, maintain mechanical strength, and have oxidative resistance, but it is unclear whether they do so. Questions/purposes The primary objective of this study therefore was to determine if a second-generation annealed material has low linear wear at 5 years followup. Secondary objectives were to evaluate for overall survivorship, implant fixation, osteolysis, and effect of socket inclination on wear. Methods In a multicenter prospective study, we radiographically evaluated 155 patients (167 hips) at 3 years, 124 patients (132 hips) at 4 years, and 46 patients (51 hips) at 5 years. The linear head penetration rate was measured at 6 weeks, 1 year, and yearly through 5 years. Results The head penetration per year after the first year of bedding-in was 0.024 mm per year at 3 years, 0.020 mm per year at 4 years, and 0.008 mm per year at 5 years. The average wear rate over 5 years was 0.015 mm per year and represents a 58% improvement over a first-generation annealed highly cross-linked polyethylene. The Kaplan- Meier survivorship (revision for any reason) was 97.8%. We revised no hip for bearing surface failure and observed no osteolysis. Socket inclination did not affect linear wear. Conclusions These data suggest the linear wear rate for a second-generation annealed highly cross-linked polyethylene is no greater than that for historic controls of first-generation highly cross-linked polyethylenes, and no untoward complications were encountered with this new material. © The Association of Bone and Joint Surgeons® 2012.

Lee R.K.,Stryker Orthopaedics
Surgical technology international | Year: 2010

Metal-on-metal bearings are promoted as a low wear bearing alternative to traditional hip replacement bearings. While most in vitro studies support this, recent clinical reviews have found a significant number of early revisions in some designs of metal-on-metal bearings related to wear. Metal-on-metal bearings exhibit a bi-phasic wear pattern with high initial wear that generally settles down to low steady state wear. Previous publications from the authors have found that steady state wear occurs due to the formation of a critical conforming contact area. This contact area was found to be surprisingly constant regardless of bearing size, clearance, or even contact mode. The authors hypothesized that steady state wear may never be reached if formation of this critical conforming contact area is disrupted. Several hip simulator tests were performed to assess the wear performance of generic metal-on-metal samples at various angles of inclination. Three-dimensional modeling was performed on the generic bearing design as well as typical resurfacing and hemispherical bearing designs including various sizes and clearance ranges. Simulator results support the hypotheses, and wear rates were linear or accelerating when the critical contact area size could not be achieved due to its proximity to the rim of the bearing. Modeling studies show a correlation between bearing size and design and the maximum inclination angle allowed to reach steady state conditions. Smaller bearing size and shallower cup designs were found to reduce the maximum safe inclination angle and this corresponds to clinical observation of increased failure rates in these bearings. This simple method for assessing runaway wear risk can be utilized in the design of more robust and forgiving metal-on-metal bearings.

D'Antonio J.A.,Greater Pittsburgh Orthopaedics Association | Capello W.N.,Indiana University | Naughton M.,Stryker Orthopaedics
Clinical Orthopaedics and Related Research | Year: 2012

Background: Ceramic bearings were introduced to reduce wear and increase long-term survivorship of total hip arthroplasty. In a previous study comparing ceramic with metal-on-polyethylene at 5 to 8 years, we found higher survivorship and no osteolysis for the ceramic bearings. Questions/Purposes: We asked whether ceramic bearings have equal or superior survivorship compared with that for metal-on-polyethylene at longer followup; we also determined survivorship of the implant systems, the presence or absence of radiographic osteolysis, and incidence of device squeaking. Methods: Five surgeons at five sites have followed 189 patients (216 hips) for a minimum of 10 years and average of 10.3 years (range, 10-12.4 years) comparing alumina ceramic bearings (144 hips) with cobalt chrome-on-polyethylene bearings (72 hips). We determined Kaplan-Meier survivorship of the bearing surface and implant systems and collected radiographic and clinical data. Results: We observed no difference between the control metal-on-polyethylene and the alumina-bearing couple cohorts with regard to bearing-related failures (98.9% versus 99.1%). Revisions for any reason occurred in 10.5% of the control patients and 3.1% of the patients with alumina bearings. All femoral implants remain well fixed (100%), whereas one acetabular component (1%) is unstable in the control group. Osteolysis occurred in 26% of the control patients and in none of the patients with alumina bearings. Squeaking occurred in two of 144 hips (1.4%) of the patients with ceramic bearings. Conclusions: Patients receiving the ceramic-on-ceramic bearings had fewer revisions for any reason and less osteolysis than the control metal-on-polyethylene at 10 years. Our data suggest ceramic bearings continue to provide an option for the young and more active patient and provide for a measure to compare other new alternative bearings that are currently available. Level of Evidence: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. © 2011 The Association of Bone and Joint Surgeons®.

Essner A.,Stryker Orthopaedics
The journal of knee surgery | Year: 2011

It is difficult for surgeons to make the decision on which design or material to use given the different options available. Marketing claims and direct-to-consumer advertising certainly complicate this further. One company may claim a higher percentage of wear reduction with their bearing surfaces compared with those of another manufacturer. If the percentage of wear reduction is lower, it is unclear as to whether this creates a more effective technology for reducing wear in the clinical situation. The relative contribution and relationship of design and materials to wear performance must be considered before making that important judgment. To examine the overall influence of implant design on wear reduction, a knee simulator study was undertaken. This simulator study compared the Oxinium Genesis II system with the Triathlon Conventional and Triathlon X3 knee systems under physiologic stair-climb loading and motion profiles. This allows a similar comparison of material effect within one design but also a global comparison across designs. Test results show the Triathlon Conventional and Triathlon X3 knee systems have superior wear resistance compared with that of the Genesis II Oxinium system under stair-climbing simulation. This finding indicates that implant design plays a more significant role in knee wear reduction than material. Although material technology may improve a given knee system's ability to wear, design geometry has a first-order effect and should be addressed before materials. This study represents an effort to differentiate design effect from two different approaches to material enhancement. The results of this study support the predominance of design in knee replacement wear performance. Ultimately, only clinical evidence such as published studies or outcomes reported in the available joint registries will establish whether any material or design can achieve a 30-year outcome.

Capello W.N.,Indiana University | D'Antonio J.A.,Greater Pittsburgh Orthopaedics Association | Naughton M.,Stryker Orthopaedics
Clinical Orthopaedics and Related Research | Year: 2014

Background: Periprosthetic fractures can occur both intraoperatively and postoperatively with implantation of cementless tapered stems. Questions/purposes: In a large cohort of patients receiving cementless, proximally hydroxyapatite-coated femoral implants, we answered the following questions: What was the incidence of intraoperative and postoperative fractures associated with the implant? What were the fracture patterns as classified by the Vancouver classification system? Did the Vancouver classification represent the fracture patterns found? How were the fractures treated and what were the treatment outcomes; that is, how many fractures healed and did the stems osseointegrate? Methods: We evaluated 1039 hips (932 patients) from three prospective studies. The hips were divided into three groups: no fractures, intraoperative fractures, and postoperative fractures. Demographic differences among the groups were noted. Postoperative fractures were classified using the Vancouver classification system. We judged stem stability using Engh's criteria and fracture union was determined by the treating surgeon and confirmed by the authors. Results: We identified 58 periprosthetic fractures in the 1039 hips (5.6%): 38 intraoperative (3.7%) and 20 postoperative (1.9%). Eleven of the postoperative fractures were classifiable by the original Vancouver classification system and nine were of the newly described "clamshell" variety, not classifiable by this system. No intraoperative fractures extended below the lesser trochanter. Twenty-five of these fractures were treated with a single cable or cerclage wire. The remaining received no specific treatment. Of the 20 postoperative fractures, five were treated nonoperatively. All stems osseointegrated. Conclusions: Both intraoperative and postoperative fractures can be managed with success when the stem is stabilized or found to be osseointegrated. An adjustment to the Vancouver classification is suggested to include the clamshell fracture, which has not been previously described. Level of Evidence: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence. © 2013 The Association of Bone and Joint Surgeons®.

Korduba L.A.,Stryker Orthopaedics | Wang A.,Stryker Orthopaedics
Wear | Year: 2011

The phenomenon of orientation softening suggests that during multi-directional motion the principal direction experiences hardening due to molecular orientation, while the secondary direction experiences softening. Multi-directional motion occurs during gait for both hips and knees, and its effect on the wear of ultra-high molecular weight polyethylene (UHMWPE) is still not fully understood. The purpose of this study was to evaluate the phenomenon of orientation softening using a highly crosslinked polyethylene (HXPE). Both virgin polyethylene and HXPE pins were articulated against cobalt-chromium discs using an OrthoPod™ wear tester. Six different motion paths were used, ranging from a square pattern to a linear track. Gravimetric weight measurements were periodically collected and scanning electron micrographs were taken after the completion of each motion path. The results show the motion path has a significant effect on the wear rate of virgin polyethylene, but no significant effect on the wear of HXPE. © 2011 Elsevier B.V.

News Article | February 18, 2017

(PRLEAP.COM) Tampa, Florida. – Saunders & Walker P.A., a National Consumer Justice Law Firm, announces a defective product lawsuit against Howmedica Osteonics Corp., also known as Stryker Orthopaedics. The suit alleges that Stryker's hip replacement devices caused severe and permanent physical injuries to Francis T. Hassett after he was implanted with them during bilateral hip implant surgeries. Stryker was served with the lawsuit on February 3, 2017.Francis T. Hassett, who was suffering from osteoarthritis, underwent right hip replacement surgery in 2009 and left hip replacement surgery in 2011. Doctors implanted Stryker's Accolade TMZF® Hip Stem and LFIT Anatomic V40 Femoral Head into both of Mr. Hassett's hips. By 2016, he was forced to undergo additional hip surgeries to remove the bad hips after it was found that Stryker's products had corroded and released metal ions into his body. The Stryker hips caused adverse local tissue reaction known as ALVAL and chromium and cobalt metal toxicity.The company not only designed and manufactured its hip replacement prosthesis in a substandard manner but knowingly withheld crucial information from both the medical community and the public. Scientists have long known that the combination of dissimilar metals causes corrosion and poses a danger to patients. In spite of that, Stryker falsely claimed that its unique device could resist corrosion and fretting. The lawsuit argues that the company's defective product, combined with misleading advertising, directly led to the plaintiff's injuries.Francis Hassett is not alone. Stryker's hip systems have harmed many patients, leading to product recalls and high revision surgery rates. Indeed, this most recent lawsuit is one of over 100 lawsuits filed against Stryker as a result of its defective hip systems. In light of the evidence, Saunders & Walker P.A. demands a trial by jury on behalf of Plaintiff Francis T. Hassett and his wife Kay Hassett.Anyone who wants to reference the Stryker Orthopaedics case can find it filed as Case 8:17-cv-00221-VMC-JSS in the United States District Court, Middle District of Florida, Tampa Division. Interested parties can also visit the Saunders & Walker P.A. website to learn more about our actions against the medical manufacturer. Those who have suffered injury as a result of Stryker's hip systems should call the law firm at 1-800-748-7115.

News Article | February 21, 2017

MAHWAH, N.J., Feb. 21, 2017 /PRNewswire/ -- Stryker Orthopaedics is pleased to announce its second PGA TOUR stop of 2017 with a first-ever appearance at The Honda Classic in Palm Beach Gardens, FL. Throughout the tournament, Stryker will further its commitment to joint health and to...

MAHWAH, N.J., Nov. 8, 2016 /PRNewswire/ -- This week, Stryker Orthopaedics will wrap up its third year as the Official Joint Replacement Products of the PGA TOUR and PGA TOUR Champions® at the Charles Schwab Cup Championship in Scottsdale, AZ. This weekend marks the eleventh tournament...

News Article | November 22, 2016

SALT LAKE CITY, UT--(Marketwired - Nov 22, 2016) -  Amedica Corporation ( : AMDA), a manufacturer of silicon nitride implants in the spine market is pleased to announce the appointment of Dana Lyons as Vice President of Sales and Marketing. Mr. Lyons will lead the effort to increase the adoption of silicon nitride implants in the spinal fusion market and deliver revenue growth. He brings over 27 years of sales and sales management experience in the medical device industry. Mr. Lyons joins Amedica after holding multiple sales management and sales leadership positions with Stryker Orthopaedics, Zimmer Spine, and Zimmer Biomet Spine. During his tenure as Sales Vice President with Zimmer Spine and in conjunction with the Zimmer Spine executive leadership team, Zimmer Spine delivered 5 consecutive quarters of growth during 2014-2015. After the Zimmer and Biomet merger in June of 2015, Mr. Lyons successfully integrated the sales organizations of both Zimmer Spine and Biomet Spine in the Central Region of the United States. Mr. Lyons said: "I am excited to join Amedica at a critical turn-around stage, when the spine market is looking for a new material platform. We can drive the adoption of silicon nitride in the spinal fusion market, where it is the perfect solution for relevant clinical concerns. The unique material attributes of silicon nitride create an ideal choice for spinal fusion surgery." The FDA also notified the company that the new pedicle screw system, Taurus, has been cleared for commercialization. The company is on target for surgical implantation and a full market launch of the Taurus system by the end of the year. Mr. Lyons will execute a strategy for expanded introduction of new spine products, such as the lateral lumbar fusion devices and the Taurus pedicle screw system. "Approval of our metals product portfolio is immediately relevant, and our new sales team will work toward proper positioning of this system, to leverage surgeon interest and drive revenue growth," said Dr. Bal. B. Sonny Bal, MD, MBA, JD, PhD; the CEO and President of Amedica Corporation added: "Amedica is building a top-tier sales team with skilled veterans from the spine industry, such as Mr. Lyons. Going forward, our focus is on driving sales, surgeon engagement, and data collection to validate the unparalleled volume of basic material science data that we have already published. Surgeon intrigue about our material, and a market need for clinical advantages that only our material can deliver, combine to make spine an attractive growth opportunity. As part of the new sales team, I will focus on driving clinical trials, surgeon relations, and publishing clinical data to impact our revenue growth." Separately, the company has been notified that the FDA did not clear its 510(k) premarket application to commercialize Valeo C+CsC, a composite spinal fusion device, even though the device is marketed in Europe with successful outcomes. "While the FDA reluctance to clear our composite silicon nitride device that incorporates the world's first structural porous bioceramic under the 510(k) program is disappointing, we are working with the FDA to examine other pathways to introduce this proprietary technology to the U.S. market as expeditiously as possible," said Dr. Bal. About Amedica Corporation Amedica is focused on the development and application of interbody implants manufactured with medical-grade silicon nitride ceramic. Amedica markets spinal fusion products and is developing a new generation of wear- and corrosion-resistant implant components for hip and knee arthroplasty as well as dental applications. The Company's products are manufactured in its ISO 13485 certified manufacturing facility and through its partnership with Kyocera, one of the world's largest ceramic manufacturers. Amedica's FDA-cleared and CE-marked spine products are currently marketed in the U.S. and select markets in Europe and South America through its distributor network and its growing OEM and private label partnerships. For more information on Amedica or its silicon nitride material platform, please visit Forward-Looking Statements This press release contains statements that constitute forward-looking statements within the meaning of the Securities Act of 1933 and the Securities Exchange Act of 1934, as amended by the Private Securities Litigation Reform Act of 1995. Such statements are subject to risks and uncertainties that could cause actual results to differ materially from those contemplated within this press release. A discussion of those risks and uncertainties can be found in Amedica's Risk Factors disclosure in its Annual Report on Form 10-K, filed with the Securities and Exchange Commission (SEC) on March 23, 2016, and in Amedica's other filings with the SEC. Amedica disclaims any obligation to update any forward-looking statements.

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