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Dive into the research topics where Thomas Gregory is active.

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Featured researches published by Thomas Gregory.


American Journal of Sports Medicine | 2009

Repair of Distal Biceps Tendon Rupture Using a Suture Anchor: Description of a New Endoscopic Procedure

Thomas Gregory; Philippe Roure; Didier Fontes

Background Repair of a distal biceps tendon rupture is a challenging procedure and, to date, there is no consensus as to which technique should be used because of the specific complications reported for each. Purpose A new endoscopic technique is described that uses a suture anchor to repair distal biceps tendon ruptures. Study Design Case series; Level of evidence, 4. Methods The results of a cohort of 23 patients (25 elbows) are reported with a median follow-up of 26 months. All patients were male and their median age was 44 years (range, 30-58). Ten of the patients (12 ruptures) were professional athletes or had a high level of physical activity. All repairs were performed via a 3-cm incision made in the “safe area” of the anterior crease of the forearm. The whole procedure was performed within the tendon sheath. The tendon was reinserted using a single anchor. Results Of the 23 patients, 22 were satisfied and 20 patients returned to their preinjury sports and jobs. There was a mean loss of 8.6° of pronation and 5° of supination. A single severe neurologic complication, which required a second surgical procedure, was reported. There were also 2 ectopic ossifications without clinical consequences and a transitory radial nerve paralysis. Conclusions This study clearly demonstrated that endoscopic repair of the ruptured distal biceps tendon is safe, effective, and reproducible. It provides good functional outcome and early recovery with few complications. Postoperative median nerve palsy due to edema is a possible concern for patients involved in athletic activity and with a history of nerve entrapment; thus this technique should be used with caution in this group of patients.


Journal of Orthopaedic Research | 2009

Glenoid Loosening after Total Shoulder Arthroplasty: An In Vitro CT-Scan Study

Thomas Gregory; Ulrich Hansen; Fabienne Taillieu; Toby Baring; Nicolas Brassart; Celine Mutchler; Andrew A. Amis; Bernard Augereau; Roger Emery

Glenoid fixation failure has only been grossly characterized. This lack of information hinders attempts to improve fixation because of a lack of methodologies for detecting and monitoring fixation failure. Our goal was twofold: to collect detailed data of glenoid fixation fracture, and to investigate computed tomography (CT)‐scanning as a tool for investigations of fixation failure. Six cadaver scapulas and six bone‐substitute specimens were cyclically loaded and CT‐scanned at clinical settings after 0, 1,000, 5,000, 10,000, 30,000, 50,000 and 70,000 load cycles. The fixation status was evaluated by inspection of the scans. After 70,000 cycles, the specimens were sectioned, and the fixation inspected by microscopy. The results of the microscopy analysis were compared to the CT‐scan analysis. Fracture of the glenoid fixation initiated at the edge of the glenoid rim and propagated towards and around the keel of the implant. The entire process from initiation to complete fracture took place at the polyethylene implant–cement interface, while the cement, the adjacent bone, and the cement–bone interface remained intact. Thus, strengthening the polyethylene–cement interface should improve glenoid fixation. Microscopy results validated the CT methodology, suggesting that the CT technique is reliable.


PLOS ONE | 2013

Accuracy of Glenoid Component Placement in Total Shoulder Arthroplasty and Its Effect on Clinical and Radiological Outcome in a Retrospective, Longitudinal, Monocentric Open Study

Thomas Gregory; Andrew Sankey; Bernard Augereau; Eric Vandenbussche; Andrew A. Amis; Roger Emery; Ulrich Hansen

Background The success of Total Shoulder Arthroplasty (TSA) is believed to depend on the restoration of the natural anatomy of the joint and a key development has been the introduction of modular humeral components to more accurately restore the patient’s anatomy. However, there are no peer-reviewed studies that have reported the degree of glenoid component mal-position achieved in clinical practice and the clinical outcome of such mal-position. The main purpose of this study was to assess the accuracy of glenoid implant positioning during TSA and to relate it to the radiological (occurrence of radiolucent lines and osteolysis on CT) and clinical outcomes. Methods 68 TSAs were assessed with a mean follow-up of 38+/−27 months. The clinical evaluation consisted of measuring the mobility as well as of the Constant Score. The radiological evaluation was performed on CT-scans in which metal artefacts had been eliminated. From the CT-scans radiolucent lines and osteolysis were assessed. The positions of the glenoid and humeral components were also measured from the CT scans. Results Four position glenoid component parameters were calculated The posterior version (6°±12°; mean ± SD), the superior tilt (12°±17°), the rotation of the implant relative to the scapular plane (3°±14°) and the off-set distance of the centre of the glenoid implant from the scapular plane (6±4 mm). An inferiorly inclined implant was found to be associated with higher levels of radiolucent lines while retroversion and non-neutral rotation were associated with a reduced range of motion. Conclusion this study demonstrates that glenoid implants of anatomic TSA are poorly positioned and that this malposition has a direct effect on the clinical and radiological outcome. Thus, further developments in glenoid implantation techniques are required to enable the surgeon to achieve a desired implant position and outcome.


Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine | 2007

Developments in shoulder arthroplasty

Thomas Gregory; Ulrich Hansen; Roger Emery; Bernard Augereau; Andrew A. Amis

Abstract Indications for shoulder arthroplasty are numerous, mainly owing to glenohumeral osteoarthritis, rheumatoid arthritis, or fracture of the proximal humerus. However, the anatomy and the biomechanics of the shoulder are complex and shoulder arthroplasty has evolved significantly over the past 30 years. This paper presents the main recent evolutions in shoulder replacement, the questions not answered yet, and the main future areas of research. The review focuses firstly on the design, positioning, and fixation of the humeral component, secondly on the design, positioning, and fixation of the glenoid implant, and thirdly on other concepts of shoulder arthroplasty such as the reversed prosthesis, the cementless surface replacement arthroplasty, and the bipolar arthroplasty. This review demonstrates that more research is needed. Although, in the long term, large randomized trials are needed to settle the fundamental questions of what type of replacement and which kind of fixation should be used, biomechanical research in the laboratory should be focused primarily on the comprehension of glenoid loosening, which is a major cause of total shoulder arthroplasty failure, and the significance of radiolucent lines which are often seen but with no clear understanding about their relation with failure.


Injury-international Journal of The Care of The Injured | 2016

Terrorist attacks in Paris: Surgical trauma experience in a referral center

Thomas Gregory; Thomas Bihel; Pierre Guigui; Jérôme Pierrart; Benjamin Bouyer; Baptiste Magrino; Damien Delgrande; Thibault Lafosse; Jaber Al Khaili; Antoine Baldacci; G. Lonjon; Sébastien Moreau; L. Lantieri; Jean-Marc Alsac; Jean-Baptiste Dufourcq; Jean Mantz; Philippe Juvin; Philippe Halimi; Richard Douard; Olivier Mir; E. Masmejean

BACKGROUND On November 13th, 2015, terrorist bomb explosions and gunshots occurred in Paris, France, with 129 people immediately killed, and more than 300 being injured. This article describes the staff organization, surgical management, and patterns of injuries in casualties who were referred to the Teaching European Hospital Georges Pompidou. METHODS This study is a retrospective analysis of the pre-hospital response and the in-hospital response in our referral trauma center. Data for patient flow, resource use, patterns of injuries and outcomes were obtained by the review of electronic hospital records. RESULTS Forty-one patients were referred to our center, and 22 requiring surgery were hospitalized for>24h. From November 14th at 0:41 A.M. to November 15th at 1:10 A.M., 23 surgical interventions were performed on 22 casualties. Gunshot injuries and/or shrapnel wounds were found in 45%, fractures in 45%, head trauma in 4.5%, and abdominal injuries in 14%. Soft-tissue and musculoskeletal injuries predominated in 77% of cases, peripheral nerve injury was identified in 30%. The mortality rate was 0% at last follow up. CONCLUSION Rapid staff and logistical response, immediate access to operating rooms, and multidisciplinary surgical care delivery led to excellent short-term outcomes, with no in-hospital death and only one patient being still hospitalized 45days after the initial event.


Spine | 2013

Prognostic scoring systems for spinal metastases in the era of anti-VEGF therapies.

Thomas Gregory; Romain Coriat; Olivier Mir

Study Design. Spine Update on prognostic scoring systems for spinal metastases in the era of anti-vascular endothelial growth factor (VEGF) therapies. Objective. To review and discuss the strengths and weaknesses of available scoring systems since the introduction of molecular targeted anticancer agents. Summary of Background Data. Molecular targeted anticancer agents have dramatically improved survival of patients in various cancers, including renal cancer. Methods. Using prognostic scoring systems for spinal metastases and recent survival data of patients with cancers treated with anti-VEGF agents, a review was undertaken, evaluating the strengths and weaknesses of available prognostic scoring systems designed in the 1990s and early 2000s among patients treated with recent agents (available from 2005). Results. All available prognostic scoring systems for spinal metastases include the primary tumor as a key variable. The estimation of life expectancy with these systems is inaccurate in view of recent survival data, as illustrated in renal cancer. The underestimation of life expectancy and subsequent inadequate treatment of spinal metastases may lead to dramatic alteration of the quality of life. Conclusion. The assessment of the available scores in recent cohorts of patients is mandatory to test their current validity and evidence the need for aggressive surgical management. New scoring systems taking into account the gain in survival induced by recent anticancer agents will likely be warranted in a close future.


Orthopaedics & Traumatology-surgery & Research | 2013

Surgical treatment of three and four-part proximal humeral fractures

Thomas Gregory; Eric Vandenbussche; Bernard Augereau

Three- and four-part fractures of the proximal humerus are usually treated surgically. Open reduction with internal fixation (ORIF) is the method of choice in younger patients. Anatomic reduction of the tuberosities is crucial to ensure that, in the event of poorly tolerated avascular necrosis of the humeral head, hemiarthroplasty can be performed under optimal conditions. Suboptimal outcomes may occur after ORIF, as less-than-perfect reduction and fixation is poorly tolerated at the shoulder. Preoperative computed tomography must be performed routinely to analyse fragment displacement and comminution, classify the fracture, assess humeral head vitality, and evaluate the mechanical properties of the underlying bone. Fracture reduction relies on principles that are shared by the various available techniques. Reduction of each fragment should be assessed separately. Reduction of the humeral head to the shaft should be performed before reduction of the tuberosities. The fixation technique should ensure stability of the anatomic reduction, with secure fixation of the tuberosities and a minimal risk of material migration into the joint. Here, we provide a detailed discussion of the various techniques, with their advantages and drawbacks, to help surgeons select the method that is most appropriate to each individual patient.


Clinical Microbiology and Infection | 2012

Vaccination coverage among medical residents in Paris, France

Olivier Mir; J. Adam; R. Gaillard; Thomas Gregory; N. Veyrie; Y. Yordanov; P. Berveiller; B. Chousterman; P. Loulergue

Medical residents are particularly exposed to the risk of occupational infection. We aimed to determine the vaccination coverage in residents with an anonymous self-reporting electronic questionnaire. A total of 250 residents took part in this survey. Vaccination rates were particularly high for mandatory vaccinations (diphtheria, tetanus, poliomyelitis, hepatitis B virus and tuberculosis). Regarding recommended vaccinations (influenza, 45.6%; pertussis, 65.2%; measles, 62.8%; varicella, 62.8%), rates were insufficient to prevent hospital epidemics, but higher than those reported in other healthcare workers. Further immunization programmes should target residents, and not only senior healthcare workers, with a critical role for occupational medicine departments.


Journal of Biomechanics | 2015

Digital volume correlation and micro-CT: An in-vitro technique for measuring full-field interface micromotion around polyethylene implants.

Chamaiporn Sukjamsri; Diogo M. Geraldes; Thomas Gregory; Farah Ahmed; David Hollis; Samuel Schenk; Andrew A. Amis; Roger Emery; Ulrich Hansen

Micromotion around implants is commonly measured using displacement-sensor techniques. Due to the limitations of these techniques, an alternative approach (DVC-μCT) using digital volume correlation (DVC) and micro-CT (μCT) was developed in this study. The validation consisted of evaluating DVC-μCT based micromotion against known micromotions (40, 100 and 150 μm) in a simplified experiment. Subsequently, a more clinically realistic experiment in which a glenoid component was implanted into a porcine scapula was carried out and the DVC-μCT measurements during a single load cycle (duration 20 min due to scanning time) was correlated with the manual tracking of micromotion at 12 discrete points across the implant interface. In this same experiment the full-field DVC-μCT micromotion was compared to the full-field micromotion predicted by a parallel finite element analysis (FEA). It was found that DVC-μCT micromotion matched the known micromotion of the simplified experiment (average/peak error=1.4/1.7 μm, regression line slope=0.999) and correlated with the micromotion at the 12 points tracked manually during the realistic experiment (R(2)=0.96). The DVC-μCT full-field micromotion matched the pattern of the full-field FEA predicted micromotion. This study showed that the DVC-μCT technique provides sensible estimates of micromotion. The main advantages of this technique are that it does not damage important parts of the specimen to gain access to the bone-implant interface, and it provides a full-field evaluation of micromotion as opposed to the micromotion at just a few discrete points. In conclusion the DVC-μCT technique provides a useful tool for investigations of micromotion around plastic implants.


Acta Orthopaedica | 2012

Total shoulder arthroplasty does not correct the orientation of the eroded glenoid

Thomas Gregory; Ulrich Hansen; Roger Emery; Andrew A. Amis; Celine Mutchler; Fabienne Taillieu; Bernard Augereau

Background and purpose Alignment of the glenoid component with the scapula during total shoulder arthroplasty (TSA) is challenging due to glenoid erosion and lack of both bone stock and guiding landmarks. We determined the extent to which the implant position is governed by the preoperative erosion of the glenoid. Also, we investigated whether excessive erosion of the glenoid is associated with perforation of the glenoid vault. Methods We used preoperative and postoperative CT scans of 29 TSAs to assess version, inclination, rotation, and offset of the glenoid relative to the scapula plane. The position of the implant keel within the glenoid vault was classified into three types: centrally positioned, component touching vault cortex, and perforation of the cortex. Results Preoperative glenoid erosion was statistically significantly linked to the postoperative placement of the implant regarding all position parameters. Retroversion of the eroded glenoid was on average 10° (SD10) and retroversion of the implant after surgery was 7° (SD11). The implant keel was centered within the vault in 7 of 29 patients and the glenoid vault was perforated in 5 patients. Anterior cortex perforation was most frequent and was associated with severe preoperative posterior erosion, causing implant retroversion. Interpretation The position of the glenoid component reflected the preoperative erosion and “correction” was not a characteristic of the reconstructive surgery. Severe erosion appears to be linked to vault perforation. If malalignment and perforation are associated with loosening, our results suggest reorientation of the implant relative to the eroded surface.

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Bernard Augereau

Paris Descartes University

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Olivier Mir

Institut Gustave Roussy

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E. Masmejean

Paris Descartes University

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Jérôme Pierrart

Paris Descartes University

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Roger Emery

Imperial College London

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Damien Delgrande

Paris Descartes University

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Romain Coriat

Paris Descartes University

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