Timothy M Wright

Hospital for Special Surgery, New York, New York, United States

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Publications (130)344.52 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Dual mobility designs were introduced to increase stability and reduce the risk of dislocation, both common reasons for surgical revision following total hip arthroplasty. The in vivo behavior of dual mobility constructs remains unclear, and to our knowledge, no data have been published describing in vivo surface damage to the polyethylene bearing surfaces.
    No preview · Article · Jan 2016
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    ABSTRACT: Background: High-flex (HF) total knee arthroplasties are modified posterior-stabilized (PS) implants designed to accommodate greater flexion. Methods: We examined differences between HF and PS retrieved tibial inserts with regard to polyethylene surface damage. Twenty HF inserts from each of 3 manufacturers were matched using patient demographics with 20 PS inserts from the same manufacturers. Ranges of motion between matched patients were not different. Results: Based on subjective damage scores, no differences were detected between HF and PS groups. Differences were found, however, among manufacturers, consistent with design approaches taken for PS and HF implants. Conclusion: In our series, high flexion did not influence damage, although this was likely influenced by the fact that few HF patients in our study had larger range of motions than their PS counterparts.
    No preview · Article · Oct 2015 · The Journal of arthroplasty
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    ABSTRACT: Fretting and corrosion at head-neck junctions of total hip arthroplasties (THAs) have been associated with adverse local tissue reactions in patients with both metal-on-polyethylene (MoP) and metal-on-metal (MoM) prostheses. Femoral head size contributes to the severity of fretting and corrosion in large-diameter MoM THAs, but its impact on such damage in MoP THAs remains unknown. (1) Is femoral head size associated with increased fretting or corrosion at the head-neck junction in MoP total hips? (2) Is duration of implantation associated with increased fretting or corrosion? The severity of fretting/corrosion on surfaces of head tapers and stem trunnions was visually examined in 154 MoP THAs retrieved as part of 3282 revision surgeries performed at our institution between January 1, 2007, and December 31, 2013. Fretting and corrosion damage were subjectively graded by two independent observers on a 1 to 4 scale, and their relations to head size, alloy combinations, taper/trunnion design, length of implantation (LOI), and location were investigated. Differences in scores never exceeded one grade, and this occurred in only 17% of examined implants. With the available implants, the study provided 88% power to detect differences of 0.5 in fretting or corrosion scores in these analyses. Fretting and corrosion of the tapers and the trunnions were not affected by head size (p = 0.247, p = 0.471, p = 0.837, and p = 0.868, respectively), although taper/trunnion design affected taper fretting (p = 0.005) and corrosion (p = 0.0031) and trunnion fretting (p = 0.0028). Head taper fretting (observed in 73% of heads) increased with LOI, but head taper corrosion (noted in 93% of heads) was not affected. Trunnion fretting (observed in 86% of stems) was more severe in mixed-alloy combinations and with increased LOI and was more severe proximally. Trunnion corrosion (noted in 72% of stems) was also location-dependent with greater corrosion distally. Fretting and corrosion are regular occurrences in MoP THAs, but neither damage type was related to femoral head size. Conversely, taper design, LOI, and alloy combination affected the severity of both fretting and corrosion. Although it has been suggested that trunnion corrosion seen in MoP bearings is a function of larger diameter heads, our data suggest that larger femoral heads may be used for increased damage at the modular junction of MoP THAs.
    No preview · Article · Jul 2015 · Clinical Orthopaedics and Related Research
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    ABSTRACT: Femoral stems with dual-taper modularity were introduced to allow independent control of length, offset, and version. Corrosion and fretting related to micromotion at the neck-stem junction are thought to stimulate an adverse local tissue reaction (ALTR). Analysis of 60 consecutively retrieved modular-neck stem implants (Rejuvenate, Stryker) revised primarily for ALTR was done to determine the variables influencing corrosion and fretting patterns at the neck-stem interface. Taper damage evaluation was performed with stereomicrocopic analysis with two observers. Evidence of fretting and corrosion was seen at the neck-stem taper in all implants, including three implants revised for periprosthetic fractures within four weeks of the index surgery indicating that this process starts early. Femoral stems paired with the long overall neck lengths had significantly higher corrosion scores. Correlation of the corrosion severity at particular locations with the length of implantation suggests that the neck-stem junction experiences cyclic cantilever bending in vivo. The positive correlation between the length of implantation and fretting/corrosion scores bodes poorly for patients who still have this implant. Scanning electron microscopy on a subset of specimens was also performed to evaluate the black corrosion material. We strongly urge frequent follow-up exams for every patient with this particular modular hip stem. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Mar 2015 · The Journal of arthroplasty
  • Timothy M. Wright · Suzanne A. Maher
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    ABSTRACT: The complex interaction between biomechanics and biology in the etiology and progression of arthritis remains unknown. The challenge becomes one of understanding joint mechanics in both normal and traumatized joints. This requires consideration of how loads are transferred across the joint, how they are distributed among the joint tissues, and how injury affects joint stability. Lessons learned from tribology of man-made joints underscore the importance of the interaction between joint force and stability. Animal models used to induce arthritic changes, often by creating joint instability, are hampered by poor control and inadequate measurement of the mechanical environment. However, considerable progress is underway, supported by increases in computational tools and computing power, the availability of mouse models that can incorporate specific genetic alterations, and more robust imaging techniques for longitudinally modeling the resulting alterations in joint tissues.
    No preview · Article · Jan 2015
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    ABSTRACT: The aims of this study were to assess damage on the surface of retrieved oxidized zirconium (OxZr) metal femoral heads, to measure surface roughness of scratches, and to evaluate the extent of surface effacement using scanning electron microscopy (SEM). Ceramic zirconia-toughened alumina heads were analyzed for comparison. OxZr femoral heads explanted for recurrent dislocation had the most severe damage (P<0.001). The median surface roughness of damaged OxZr femoral heads was 1.49μm, compared to 0.084μm for damaged ceramic heads and 0.052μm for undamaged OxZr (P<0.001). This may be of clinical concern because increased surface roughness has the potential to increase the wear of polyethylene liners articulating against these OxZr heads in THA. Copyright © 2014 Elsevier Inc. All rights reserved.
    No preview · Article · Nov 2014 · The Journal of Arthroplasty
  • Radhika J Patel · Lawrence Gulotta · Timothy M Wright · Yingxin Gao
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    ABSTRACT: Total shoulder arthroplasty is commonly performed to treat glenohumeral osteoarthritis (OA); however, little is understood of the mechanics of the reconstructed OA shoulder. We sought to establish the effects of OA-induced changes in bone density and retroversion angle on load transfer and stress distribution in the bone-implant system of the scapula. We developed finite element models of reconstructed healthy and OA scapulas with a virtually implanted glenoid prosthesis design. For the OA scapula, models with uncorrected and corrected retroversion were created. Loads were applied at the center or posteriorly on the glenoid surface. Our results suggest that with reconstruction of the corrected glenoid with a contemporary implant, cement stresses increase and the load transfer pattern changes with eccentric loads. The load transfer and local stresses in the bone-implant system in the retroverted glenoid are less sensitive to changes in loading location. Furthermore, the load transfer in the OA glenoid is less sensitive to the effect of peg proximity to the cortical shell than in the healthy glenoid. We provided evidence of how load sharing is altered among healthy, corrected OA, and retroverted OA glenoids. We demonstrated that correction of retroversion in OA glenoids may actually increase the risk for stress shielding and cement failure compared with retroverted glenoids, and OA patients can accommodate shorter pegs because of the higher glenoid bone stiffness in the OA glenoid. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.
    No preview · Article · Oct 2014 · Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons ... [et al.]
  • Stuart B Goodman · Timothy M Wright
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    ABSTRACT: The Carl T. Brighton Workshop on Implant Wear and Tribocorrosion of Total Joint Replacements was held on November 21 to 23, 2013 in Tampa, FL USA under the auspices of the Association of Bone and Joint Surgeons® and Clinical Orthopaedics and Related Research®. Overall, the workshop provided cause for optimism that the current challenges in total joint replacement will be surmounted by ongoing research, innovation and continued outcome studies and national registry data.Total joint replacement has demonstrated great success in relieving pain and improving function for many millions of patients. However, open questions and challenges remain in terms of defining appropriate patient selection and surgical technique, as well as in identifying the best bearing surfaces and implant designs, especially for younger more active patients.The workshop assembled an expert group of clinicians, biologists, bioengineers, and material scientists, and tasked the participants with formulating answers to ...
    No preview · Article · Sep 2014 · Clinical Orthopaedics and Related Research
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    ABSTRACT: Ceramic femoral heads have had promising results as a bearing surface in total hip arthroplasty. Our objective was to evaluate a series of retrieved alumina-zirconia composite ceramic femoral heads for evidence of the tetragonal to monoclinic zirconia phase transformation, metal transfer and articular surface roughness. Raman spectra showed evidence of the zirconia phase transformation in all retrieved specimens, with distinct monoclinic peaks at 183, 335, 383, and 479 cm− 1. All components displayed metal transfer. An increase in the zirconia phase transformation was seen with increasing time in vivo. No correlation between extent of zirconia phase transformation and the surface roughness was found. These short-term results suggest that the use of an alumina-zirconia composite ceramic is a viable option for femoral heads in THA.
    No preview · Article · Aug 2014 · The Journal of Arthroplasty
  • Source
    Mark P Figgie · Timothy M Wright · Denise Drinkwater
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    ABSTRACT: Erratum to: Clin Orthop Relat Res DOI 10.1007/s11999-014-3781-9In the published study, “What Design and Material Factors Impact the Wear and Corrosion Performance in Total Elbow Arthroplasties?” the Bioengineering Working Group consisted of: Thomas D. Brown PhD, University of Iowa, Iowa City, IA, USA; Darryl D. D’Lima MD, PhD, Shiley Center for Orthopaedic Research and Education, La Jolla, CA, USA; A. Seth Greenwald, D.Phil (Oxon), Orthopaedic Research Laboratories, Cleveland, OH, USA; Melinda K. Harman PhD, Clemson University, Clemson, SC, USA; Steven M. Kurtz, PhD, Exponent and Drexel University, Philadelphia, PA, USA; William M. Mihalko MD, PhD, Campbell Clinic Orthopedics and BME, Memphis, TN, USA; Orhun K. Muratoglu PhD, Massachusetts General Hospital, Boston, MA, USA; Clare M. Rimnac, PhD Case Western Reserve University, Cleveland, OH, USA; Markus A. Wimmer PhD, Rush University Medical Center, Chicago, IL.The editors regret this error.
    Preview · Article · Aug 2014 · Clinical Orthopaedics and Related Research
  • Mark P Figgie · Timothy M Wright · Denise Drinkwater
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    ABSTRACT: Where Do We Need to Go?: A clear need exists for improving the performance of total elbow arthroplasty. Many of the failures that have limited the survivorship of elbow arthroplasties thus far are mechanical in nature with wear-related problems a dominating influence. Much of what we know about the results of total elbow arthroplasty is from small studies frequently involving the designer of the implant. The establishment of total elbow arthroplasty registries coupled with the increasing regulatory burden of postmarket surveillance would lead to a better understanding of the complications and survivorship of elbow arthroplasties. Another primary goal must be to achieve a better understanding of the biomechanics of the normal elbow and how the mechanics are altered after the insertion of elbow arthroplasty components.
    No preview · Article · Jul 2014 · Clinical Orthopaedics and Related Research
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    ABSTRACT: Recent studies suggest the ‘Lewinnek safe zone’ for acetabular component position is outdated. We used a large prospective institutional registry to determine if there is a ‘safe zone’ exists for acetabular component position within which the risk of hip dislocation is low and if other patient and implant factors affect the risk of hip dislocation. Patients who reported a dislocation event within six months after hip replacement surgery were identified, and acetabular component position was measured with anteroposterior radiographs. The frequency of dislocation was 2.1% (147 of 7040 patients). No significant difference was found in the number of dislocated hips among the zones. Dislocators < 50 years old were less active preoperatively than nondislocators (p = 0.006). Acetabular component position alone is not protective against instability.
    No preview · Article · Jul 2014 · The Journal of Arthroplasty
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    ABSTRACT: Recent studies have attributed adverse local tissue reactions (ALTRs) in patients with total hip arthroplasties (THAs) to tribocorrosion debris generated by modular femoral stems. The presentations of ALTR are diverse, as are the causes of it, and the biological responses can be important reasons for failure after THA.
    No preview · Article · Jul 2014 · Clinical Orthopaedics and Related Research
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    ABSTRACT: Background The Optetrak® PS (Exactech, Inc., Gainesville, FL) has been a well-functioning posterior stabilized knee replacement since its introduction in 1995. In 2009, the Optetrak Logic® incorporated modifications to the anterior face of the tibial post and the corresponding anterior articulating surface of the femoral component to reduce edge loading on the polyethylene post. In this study, we provide the rationale for the design change and compare the damage on retrieved tibial components of both designs to demonstrate the effectiveness of the design modifications in decreasing post damage. Methods We integrated retrieval findings of tibial post damage with finite element analysis to redesign the anterior tibial post-femoral box articulation. We then used subsequent retrieval analysis on a 3:1 matched sample of 60 PS and 20 Logic® inserts to examine the impact of the design change on polyethylene damage. Results Polyethylene stresses were markedly reduced when rounded contact geometries were incorporated. The comparison of the new and old design using retrieval analysis demonstrated that the redesign led to reduction in surface damage and deformation on the tibial post. Conclusions This study shows the use of a design cycle by which a problem is identified through retrieval analysis, analytical tools are used to suggest design solutions, and then retrieval analysis is applied again on the new design to confirm improved performance. Clinical Relevance Anterior post damage has been markedly reduced through the introduction of design changes to the post-box geometry.
    No preview · Article · Jul 2014 · The Knee
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    ABSTRACT: Objective: Revision total hip arthroplasty (THA) is associated with increased cost, morbidity, and technical challenge compared to primary THA. A better understanding of the risk factors for early revision is needed to inform strategies to optimize patient outcomes. Methods: A total of 207,256 patients who underwent primary THA between 1997-2005 in California and New York were identified from statewide databases. Unique patient identifiers were used to identify early revision THA (<10 years from index procedure). Patient characteristics (demographics, comorbidities, insurance type, and preoperative diagnosis), community characteristics (education level, poverty, and population density), and hospital characteristics (annual THA volume, bed size, and teaching status) were evaluated using multivariable regression to determine risk factors for early revision. Results: The probabilities of undergoing early aseptic revision and early septic revision were 4% and <1% at 5 years, respectively. Women were 29% less likely than men to undergo early septic revision (P < 0.001). Patients with Medicaid and Medicare were 91% and 24%, respectively, more likely to undergo early septic revision than privately insured patients (P = 0.01 and P < 0.001, respectively). Hospitals performing <200 THAs annually had a 34% increased risk of early aseptic revision compared to hospitals performing >400 THAs annually (P < 0.001). Conclusion: A number of identifiable factors, including younger age, Medicaid, and low hospital volume, increase the risk of undergoing early revision THA. Patient-level characteristics distinctly affect the risk of revision within 10 years, particularly if due to infection. Our findings reinforce the need for continued investigation of the predictors of early failure following THA.
    No preview · Article · Jun 2014
  • Radhika J Patel · Timothy M Wright · Yingxin Gao
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    ABSTRACT: Glenoid loosening is the primary reason for failure after a total shoulder arthroplasty (TSA), but the failure mechanism is not yet known. This study determined how the load transfer and stress distribution are affected by the introduction of a glenoid implant. We developed a finite-element model of a scapula with and without a virtually implanted modern glenoid prosthesis design. Two load magnitudes were considered: normal and high. Loading locations were simulated at the center and at 4 eccentric positions on the glenoid. A metal-backed implant was also simulated to understand the effect of fixation stiffness. In the intact glenoid, for both center and eccentric loading, the majority of stress was distributed in the cancellous bone, whereas after a reconstruction, stresses in that region were lower. Metal-backed implants further decreased the joint load carried by the bone. Stresses in the cement layer increased during eccentric and high-magnitude loading. This study provided a basic understanding of the load-sharing phenomenon after a TSA that could explain glenoid loosening failure. Our results suggest that with reconstruction of the glenoid with a contemporary implant, the load transfer pattern is significantly altered, with eccentric and high-magnitude loads increasing stresses in the cement indicating potential for failure. The use of a metal-backed implant reduces the load carried by the bone, which may be detrimental to long-term TSA survival.
    No preview · Article · Apr 2014 · Journal of shoulder and elbow surgery / American Shoulder and Elbow Surgeons ... [et al.]
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    ABSTRACT: Backside damage of the polyethylene in TKA is a potential source of debris. The location of the tibial post in posterior-stabilized implants may influence micromotion, and thus affect backside damage, as may surface roughness. We used implant retrieval analysis to (1) examine if there were differences in backside damage among three modern posterior-stabilized implants attributable to variable surface roughness; (2) determine if the location of damage on the tibial post affected the pattern of backside damage; and (3) determine if demographics influenced backside damage. We identified 403 posterior-stabilized tibial retrieved inserts (147 NexGen(®), 152 Optetrak(®), 104 Genesis(®) II). The damage on the surfaces of the tibial posts was previously graded. The backside of the inserts (divided into quadrants) were scored for evidence of damage. The total quadrant damage was compared for each implant group, the relationship between post face damage and location of damage on the backside was determined for each implant group, and total backside damage was compared among the three implant groups. No correlation was found between the location of damage on the post and location of damage on the backside of the implant for any of the three groups. The Genesis(®) II polyethylene implants, which articulate with a highly polished tibial tray, showed a significantly lower total backside damage score (p < 0.01) when compared with the other two implant groups. The Genesis(®) II and Optetrak(®) showed significantly more damage in the posterior quadrants of the implants (p < 0.01) when compared with the anterior quadrants. A linear regression analysis revealed that lower tibial tray surface roughness was correlated with decreased damage. An implant design with a highly polished tibial tray was associated with decreased backside damage. However, tibial post design and location did not influence the location of backside damage. Our study showed that a highly polished tibial tray was associated with decreased damage to the backside of polyethylene inserts independent of post design and location. These findings should be taken into consideration when new generations of implants are designed.
    No preview · Article · Apr 2014 · Clinical Orthopaedics and Related Research
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    ABSTRACT: Squeaking after ceramic-on-ceramic total hip arthroplasty is a relatively uncommon phenomenon. It usually does not require treatment in the absence of pain, mechanical symptoms, and/or relentless squeaking. The purpose of this investigation was to report on four patients who presented with hip pain and squeaking due to fractured ceramic liners after ceramic-on-ceramic total hip arthroplasty. Four patients with painful squeaking after ceramic-on-ceramic total hip arthroplasty were seen at our institution. One patient had a revision for suspected loosening and excessive anteversion of the cup noted on radiographs and magnetic resonance imaging (MRI). The remaining three patients had a revision for audible squeaking with progressive pain. Intraoperatively, the ceramic liners of all four patients were fractured. Squeaking after ceramic-on-ceramic total hip arthroplasty rarely is a functional issue. However, painful squeaking without notable trauma may indicate fracture of the ceramic liner. Painful squeaking is difficult to evaluate by conventional imaging. When painful squeaking occurs, exploration via surgical revision is recommended in selected patients, as ceramic liner fractures may go unnoticed on radiographs and/or MRI and thus their actual prevalence may be higher than estimated. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
    No preview · Article · Jan 2014 · The Journal of Bone and Joint Surgery
  • Radhika J. Patel · Timothy M. Wright · Yingxin Gao
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    ABSTRACT: Background Glenoid loosening is the primary reason for failure after a total shoulder arthroplasty (TSA), but the failure mechanism is not yet known. This study determined how the load transfer and stress distribution are affected by the introduction of a glenoid implant. Methods We developed a finite-element model of a scapula with and without a virtually implanted modern glenoid prosthesis design. Two load magnitudes were considered: normal and high. Loading locations were simulated at the center and at 4 eccentric positions on the glenoid. A metal-backed implant was also simulated to understand the effect of fixation stiffness. Results In the intact glenoid, for both center and eccentric loading, the majority of stress was distributed in the cancellous bone, whereas after a reconstruction, stresses in that region were lower. Metal-backed implants further decreased the joint load carried by the bone. Stresses in the cement layer increased during eccentric and high-magnitude loading. Conclusion This study provided a basic understanding of the load-sharing phenomenon after a TSA that could explain glenoid loosening failure. Our results suggest that with reconstruction of the glenoid with a contemporary implant, the load transfer pattern is significantly altered, with eccentric and high-magnitude loads increasing stresses in the cement indicating potential for failure. The use of a metal-backed implant reduces the load carried by the bone, which may be detrimental to long-term TSA survival.
    No preview · Article · Jan 2014

  • No preview · Article · Oct 2013 · Arthroscopy The Journal of Arthroscopic and Related Surgery

Publication Stats

2k Citations
344.52 Total Impact Points

Institutions

  • 1983-2015
    • Hospital for Special Surgery
      • • Department of Orthopaedic Surgery
      • • Department of Biomechanics
      New York, New York, United States
  • 1988-2010
    • Weill Cornell Medical College
      • Department of Orthopaedic Surgery
      New York City, New York, United States
  • 1998-2009
    • Cornell University
      • • Department of Biomedical Engineering
      • • Sibley School of Mechanical and Aerospace Engineering
      Итак, New York, United States