Olivier Gagey

MD, PhD, Professor and Head
Head of the Orthopaedic Departement
Hôpital Bicêtre (Hôpitaux Univ... · Service d’Orthopédie et Traumatologie

Publications

  • Computer Methods in Biomechanics and Biomedical Engineering 08/2014; 17 Suppl 1:56-7. · 1.39 Impact Factor
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    ABSTRACT: All systemically administered glucocorticoids (GC) are prohibited in-competition, because of the potential ergogenic effects. Although short-term GC intake has been shown to improve performance during submaximal exercise, literature on its impact during brief intense exercise appears to be very scant. The purpose of this study was to examine the ergogenic and metabolic effects of prednisone during repeated bouts of high-intensity exercise. In a double-blind randomized protocol, ten recreational male athletes followed two 1-week treatments (Cor: prednisone, 60 mg/day or Pla: placebo). At the end of each treatment, they hopped on their dominant leg for 30 seconds three times consecutively and then hopped until exhaustion, with intervals of 5 min of passive recovery. Blood and saliva samples were collected at rest and 3 min after each exercise bout to determine the lactate, interleukin-6, interleukin-10, TNF-alpha, DHEA and testosterone values. The absolute peak force of the dominant leg was significantly increased by Cor but only during the first 30-second hopping bout (p<0.05), whereas time to exhaustion was not significantly changed after Cor treatment vs Pla (Pla: 119.9 ± 7.8; Cor: 123.1 ± 9.3 seconds). Cor intake lowered basal and end-exercise plasma interleukin-6 and saliva DHEA (p<0.01) and increased interleukin-10 (p<0.01), whereas no significant change was found in blood lactate and TNF-alpha or saliva testosterone between Pla and Cor. According to these data, short-term glucocorticoid intake did not improve endurance performance during repeated bouts of high-intensity exercise, despite the significant initial increase in absolute peak force and anti-inflammatory effect.
    Steroids 01/2014; · 2.80 Impact Factor
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    ABSTRACT: In humans, the hip joint occupies a central place in the locomotor system, as it plays an important role in body support and the transmission of the forces between the trunk and lower limbs. The study of the three-dimensional biomechanics of this joint has important implications for documenting the morphological changes associated with the acquisition of a habitual bipedal gait in humans. Functional integration at any joint has important implications in joint stability and performance. The aim of the study was to evaluate the functional integration at the human hip joint. Both the level of concordance between the three-dimensional axes of the acetabulum and the femoral neck in a bipedal posture, and patterns of covariation between these two axes were analysed. First, inter-individual variations were quantified and significant differences in the three-dimensional orientations of both the acetabulum and the femoral neck were detected. On a sample of 57 individuals, significant patterns of covariation were identified, however, the level of concordance between the axes of both the acetabulum and the femoral neck in a bipedal posture was lower than could be expected for a key joint such as the hip. Patterns of covariation were explored regarding the complex three-dimensional biomechanics of the full pelvic-femoral complex. Finally, we suggest that the lower degree of concordance observed at the human hip joint in a bipedal posture might be partly due to the phylogenetic history of the human species.
    Journal of Human Evolution 01/2014; · 4.09 Impact Factor
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    ABSTRACT: Significant alteration in hypothalamic-pituitary-adrenal function has been demonstrated in patients after short-term glucocorticoid therapy, but its impact on the circadian rhythm of steroid hormones has never been investigated. This study examined the effects of short-term prednisone administration on the diurnal patterns of dehydroepiandrosterone (DHEA) and testosterone. Saliva samples were collected from 11 healthy, physically active, male volunteers for DHEA and testosterone analysis, as follows: every 4 h from 0800 to 2000 h on 2 control days without medication, and after 1 week of oral therapeutic prednisone treatment (60 mg daily) (days 0-3). Overall, a diurnal decline in the two steroid hormones was observed on the control days. After short-term glucocorticoid administration, DHEA concentrations were significantly decreased with a complete disappearance of the DHEA diurnal pattern, which lasted 2 days post-treatment. No glucocorticoid effect was observed for testosterone. The results indicate that short-term prednisone treatment affects the circadian pattern of saliva DHEA but not testosterone in healthy active volunteers. Further studies are necessary to determine whether this alteration in DHEA circadian pattern has clinical consequences in patients with chronic glucocorticoid therapy.
    Endocrine 12/2013; · 1.42 Impact Factor
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    ABSTRACT: A recent review on the natural course of low back pain (LBP) in the general population indicated that the LBP reporting pattern is fairly constant over time. Furthermore, the LBP status at baseline (yes/no) seems to be predictive of the future course. When fluctuations occur, they seem most common between the nearest categories. However, in the majority of articles, non-responders were not taken into account in the analyses or interpretation of data, meaning that estimates may have been biased. Further, all reviewed studies included study participants of many different age groups. Data from three cross-sectional surveys over 8 years of the same cohort made it possible to answer the following questions: 1) Would the prevalence estimates of LBP be stable over time? 2) How would results change when taking into account non-responders? 3) Is the LBP reporting over the three survey periods stable at an individual level, taking into account also the non-responding group? Data from three subsequent cross-sectional surveys of a study sample were available and questions about LBP were asked at baseline and also 4 and 8 years later. Study participants were 40/41 years at base-line and initially randomly selected from the general Danish population. Data were analyzed with STATA/IC 12, and presented with percentages and 95% confidence intervals. The majority of participants reported to have had LBP in the preceding year but not having taken sick leave in relation to this pain. LBP was stable or relatively stable for the study participants as they progressed through their fifth decade. This was true on a population basis and also on an individual level. When non-responders were taken into account the results did not change. This study confirmed the results from our recent review; both presence and absence of LBP seem to be predictive for the future course. The percentage of non-responders in this type of study may not be as important as previously thought in relation to the presence/absence of LBP.
    BMC Musculoskeletal Disorders 09/2013; 14(1):270. · 1.88 Impact Factor
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    ABSTRACT: INTRODUCTION: The application of a hinged elbow external fixator is technically demanding because the hinge axis must coincide exactly with the flexion-extension axis of the elbow. The standard technique involves inserting a 3-mm K-wire freehand into the distal humerus to materialize the flexion-extension axis. We designed a guidewire device for extracorporeal hinge positioning without K-wire insertion. In a cadaver study, we compared freehand K-wire insertion and our extracorporeal technique. METHODS: In 12 cadaveric elbows, we induced acute elbow instability by sectioning the medial collateral ligament complex and the anterior and posterior capsule. A hinged external fixator was applied to each elbow using both techniques. The outcome measures were procedure duration, number of image-intensifier shots (as a measure of radiation exposure), and passive motion range after fixator implantation. RESULTS: Compared with the freehand K-wire technique, the extracorporeal technique provided greater range of motion and significantly lower values for procedure duration and number of image-intensifier shots. Data dispersion was less marked with the extracorporeal technique, indicating better reproducibility. CONCLUSION: The extracorporeal technique based on a guidewire device enabled non-invasive positioning of a hinged elbow external fixator. This technique was faster, less irradiating, and more reproducible than the freehand K-wire technique.
    Chirurgie de la Main 05/2013; · 0.30 Impact Factor
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    ABSTRACT: Genomic studies in chronic myeloid malignancies, including myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), and MPN/MDS, have identified common mutations in genes encoding signaling, epigenetic, transcription and splicing factors. In the present study, we interrogated the clonal architecture by mutation-specific discrimination analysis of single-cell-derived colonies in 28 patients with chronic myelomonocytic leukemias (CMML), the most frequent MPN/MDS. This analysis reveals a linear acquisition of the studied mutations with limited branching through loss of heterozygosity. Serial analysis of untreated and treated samples demonstrates a dynamic architecture on which most current therapeutic approaches have limited effects. The main disease characteristics are early clonal dominance, arising at the CD34(+)/CD38(-) stage of hematopoiesis, and granulomonocytic differentiation skewing of multipotent and common myeloid progenitors. Comparison of clonal expansions of TET2 mutations in MDS, MPN and CMML, together with functional invalidation of TET2 in sorted progenitors, suggests a causative link between early clonal dominance and skewed granulomonocytic differentiation. Altogether, early clonal dominance may distinguish CMML from other chronic myeloid neoplasms with similar gene mutations.
    Blood 01/2013; · 9.06 Impact Factor
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    ABSTRACT: Despite numerous studies addressing the issue, it remains unclear whether the triceps surae muscle group generates forward propulsive force during gait, commonly identified as 'push-off'. In order to challenge the push-off postulate, one must probe the effect of varying the propulsive force while annulling the effect of the progression velocity. This can be obtained by adding a load to the subject while maintaining the same progression velocity. Ten healthy subjects initiated gait in both unloaded and loaded conditions (about 30% of body weight attached at abdominal level), for two walking velocities, spontaneous and fast. Ground reaction force and EMG activity of soleus and gastrocnemius medialis and lateralis muscles of the stance leg were recorded. Centre of mass velocity and position, centre of pressure position, and disequilibrium torque were calculated. At spontaneous velocity, adding the load increased disequilibrium torque and propulsive force. However, load had no effect on the vertical braking force or amplitude of triceps activity. At fast progression velocity, disequilibrium torque, vertical braking force and triceps EMG increased with respect to spontaneous velocity. Still, adding the load did not further increase braking force or EMG. Triceps surae is not responsible for the generation of propulsive force but is merely supporting the body during walking and restraining it from falling. By controlling the disequilibrium torque, however, triceps can affect the propulsive force through the exchange of potential into kinetic energy.
    PLoS ONE 01/2013; 8(1):e52943. · 3.73 Impact Factor
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    ABSTRACT: BACKGROUND: Most patients in the secondary care sector consulting for low back pain (LBP) seem to have a more or less constant course of pain during the ensuing year. Fewer patients with LBP in the primary care sector report continual pain over a one-year period. However, not much is known about the long-term course of LBP in the general population. A systematic critical literature review was undertaken in order to study the natural course of LBP over time in the general population. METHODS: A search of articles was performed in Pubmed, Cinahl and Psychinfo using the search terms 'epidemiology'; 'low back pain' or 'back pain'; 'prospective study' or 'longitudinal study'; 'follow-up', 'natural course', 'course' or 'natural history'; 'general population' or 'working population'. Inclusion criteria were that one of the objectives was to study the course of (L)BP in the adult population, that the period of follow-up was at least 3 months, and that there were three points of observation or more. The review was undertaken by two independent reviewers using three checklists relating to description of studies, quality and outcomes. The course of LBP was established in relation to those who, at baseline, were reported not to have LBP or to have LBP. Would this course be stable, fluctuating, worsening, or improving over time? A synthesis of results in relation to common patterns was presented in a table and interpreted in a narrative form. RESULTS: Eight articles were included. Articles were different on time span, the number of surveys, and the definition of LBP. In six of the seven relevant studies, for those with no LBP at baseline, relatively substantial stable subgroups of people who continued to be LBP free were identified. In six of the seven relevant studies, definite stable subgroups of continued LBP were noted and improvement (becoming pain free) was never reported to be a common finding. CONCLUSION: The status of LBP in individuals of the general population appears to be relatively stable over time, perhaps particularly so for those without LBP at baseline.
    Chiropractic & manual therapies. 10/2012; 20(1):33.
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    ABSTRACT: A common problem in the quantification of the orientation of the femoral neck is the difficulty to determine its true axis; however, this axis is typically estimated visually only. Moreover, the orientation of the femoral neck is commonly analysed using angles that are dependent on anatomical planes of reference and only quantify the orientation in two dimensions. The purpose of this study is to establish a method to determine the three-dimensional orientation of the femoral neck using a three-dimensional model. An accurate determination of the femoral neck axis requires a reconsideration of the complex architecture of the proximal femur. The morphology of the femoral neck results from both the medial and arcuate trabecular systems, and the asymmetry of the cortical bone. Given these considerations, two alternative models, in addition to the cylindrical one frequently assumed, were tested. The surface geometry of the femoral neck was subsequently used to fit one cylinder, two cylinders and successive cross-sectional ellipses. The model based on successive ellipses provided a significantly smaller average deviation than the two other models (P < 0.001) and reduced the observer-induced measurement error. Comparisons with traditional measurements and analyses on a sample of 91 femora were also performed to assess the validity of the model based on successive ellipses. This study provides a semi-automatic and accurate method for the determination of the functional three-dimensional femoral neck orientation avoiding the use of a reference plane. This innovative method has important implications for future studies that aim to document and understand the change in the orientation of the femoral neck associated with the acquisition of a bipedal gait in humans. Moreover, the precise determination of the three-dimensional orientation has implications in current research involved in developing clinical applications in diagnosis, hip surgery and rehabilitation.
    Journal of Anatomy 09/2012; 221(5):465-76. · 2.36 Impact Factor
  • N Bonneau, O Gagey, C Tardieu
    Computer Methods in Biomechanics and Biomedical Engineering 09/2012; 15 Suppl 1:197-9. · 1.39 Impact Factor
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    ABSTRACT: Diurnal patterns of cortisol and dehydroepiandrosterone (DHEA) secretion, the two main peripheral secretory products of the hypothalamic-pituitary-adrenal neuroendocrine stress axis, have been well characterized in rest conditions but not in relation to physical exercise. The purpose of this investigation was therefore to determine the effects of an intense 90-min aerobic exercise on the waking diurnal cortisol and DHEA cycles on three separate days [without exercise, with morning exercise (10:00-11:30 h), and with afternoon exercise (14:00-15:30 h)] in nine recreationally trained soccer players. Saliva samples were collected at awakening, 30 min after awakening, and then every 2 h from 08:00 to 22:00 h. A burst of secretory activity was found for cortisol (p < 0.01) but not for DHEA after awakening. Overall, diurnal decline for both adrenal steroids was observed on resting and exercise days under all conditions. However, there was a significant increase in salivary cortisol concentrations on the morning-exercise and afternoon-exercise days at, respectively, 12:00 h (p < 0.05) and 16:00 h (p < 0.01), versus the other trials. This acute response to exercise was not evident for DHEA. The results of this investigation indicate that 90 min of intense aerobic exercise does not affect the circadian pattern of salivary adrenal steroids in recreationally trained athletes over a 16-h waking period, despite a transitory increase in post-exercise cortisol concentration. Further studies are necessary to determine whether these results are applicable to elite athletes or patients with cortisol or DHEA deficiency.
    Stress (Amsterdam, Netherlands) 06/2012; · 3.21 Impact Factor
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    ABSTRACT: In traditional as well as in geometric morphometric studies, the shape of the pelvis is often quantified after the reassembly of the two hip bones and the sacrum. However, on dry bones, the morphology of the cartilaginous tissues that form the two sacroiliac joints and the pubic symphysis before death remains unknown, leading to potential inaccuracies and errors during the reassembly process. A protocol was established to investigate the effects of reassembly on the quantification of pelvis shape. The shape of fresh pelves obtained after dissection, in which the three bones are in an anatomically relevant position, was compared with the shape of different reassemblies based on the individual dry bones of the same individuals. Our results demonstrated a significant effect of the reassembly. Variation in the reassembly process is likely related, first, to the complete absence of cartilaginous tissues on dry bones and, second, to the morphology of the sacroiliac joint which, in vivo, allows physiological movements, resulting in different potential positions of the two sacroiliac surfaces relative to one another. However, the artificial variation introduced by the reassembly process appears small compared with the biological variation between the different individuals.
    American Journal of Physical Anthropology 03/2012; 148(1):139-47. · 2.48 Impact Factor
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    ABSTRACT: Understanding the three-dimensional orientation of the coxo-femoral joint remains a challenge as an accurate three-dimensional orientation ensure an efficient bipedal gait and posture. The quantification of the orientation of the acetabulum can be performed using the three-dimensional axis perpendicular to the plane that passes along the edge of the acetabular rim. However, the acetabular rim is not regular as an important indentation in the anterior rim was observed. An innovative cadaver study of the labrum was developed to shed light on the proper quantification of the three-dimensional orientation of the acetabulum. Dissections on 17 non-embalmed corpses were performed. Our results suggest that the acetabular rim is better represented by an anterior plane and a posterior plane rather than a single plane along the entire rim as it is currently assumed. The development of the socket from the Y-shaped cartilage was suggested to explain the different orientations in these anterior and posterior planes. The labrum forms a plane that takes an orientation in between the anterior and posterior parts of the acetabular rim, filling up inequalities of the bony rim. The vectors V(L) , V(A2) and V(P) , representing the three-dimensional orientation of the labrum, the anterior rim and the posterior rim, are situated in a unique plane that appears biomechanically dependent. The three-dimensional orientation of the acetabulum is a fundamental parameter to understand the hip joint mechanism. Important applications for hip surgery and rehabilitation, as well as for physical anthropology, were discussed.
    Journal of Anatomy 02/2012; 220(5):504-13. · 2.36 Impact Factor
  • M Begin, O Gagey, M Soubeyrand
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    ABSTRACT: We present a case of bilateral posterior shoulder dislocation after an epileptic seizure. The anterior humeral-head impression fracture was 60% of the articular surface on the right shoulder and 30% on the left shoulder. We performed an early one-stage reconstruction of both humeral heads. A cancellous autograft was used on the left side and an iliac cortico-cancellous autograft on the right side, with preservation of the patient's cartilage. Three years later, the clinical and morphological results were excellent. The discussion focuses on surgical options that range from conservative treatment with excision of the damaged cartilage to immediate hemiarthroplasty. This case is original because of the preservation of the patient's cartilage during reconstruction.
    Chirurgie de la Main 02/2012; 31(1):34-7. · 0.30 Impact Factor
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    ABSTRACT: Accurate knowledge of the scapular anatomy is fundamental for the preoperative evaluation but some bony landmarks are difficult to identify. Statistical approaches based on subject-specific parametric models could be used to overcome this difficulty. The aim of this study was to propose a quantitative parametric model of the scapula and to analyze correlations between descriptive morphologic parameters. Forty-three scapulae were scanned and reconstructed. Each 3D scapula was regionalized and a simple geometric element was best fitted on each region using least square method. Descriptive parameters of each region were obtained. Correlation and linear regression analyses were performed between all measurements in order to assess parameters that can be used as predictors of the other descriptive parameters. Morphometric scapular measurements from 3D reconstructions were obtained. Correlation and linear regression analyses assessed correlations between the glenoid width and both the glenoid height and the acromial width. Also, we obtained correlation between the orientation of the inferior part of the acromion on the A-P view and on the axillary view. Parametric models are widely used in biomechanics for identifying anatomical landmarks or rotations centers of these structures. For the scapula, no such model is available. We elaborated a first parametric model of scapula based on a large database of 43 scapulae. Our morphometric measurements are very close to others founded in literature. Correlations obtained should help to progress toward relevant subject-specific models of the scapula based on reduced information.
    Anatomia Clinica 01/2012; 34(5):447-53. · 0.93 Impact Factor
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    ABSTRACT: Ultrasound examination is inexpensive, easily accessible and has numerous applications. Its diagnostic or even therapeutic use is developing in the context of hand surgery. The purpose of this work is to review the literature dealing with hand ultrasonograpy by recalling its physical basis and by showing the normal and pathological aspects of different structures and pathologies.
    Chirurgie De La Main - CHIR MAIN. 12/2011;
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    ABSTRACT: Ultrasound examination is inexpensive, easily accessible and has numerous applications. Its diagnostic or even therapeutic use is developing in the context of hand surgery. The purpose of this work is to review the literature dealing with hand ultrasonograpy by recalling its physical basis and by showing the normal and pathological aspects of different structures and pathologies.
    Chirurgie de la Main 10/2011; 30(6):368-84. · 0.30 Impact Factor
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    ABSTRACT: Disruption of the interosseous membrane is easily missed in patients with Essex-Lopresti syndrome. None of the imaging techniques available for diagnosing disruption of the interosseous membrane are completely dependable. We undertook an investigation to identify whether a simple intra-operative test could be used to diagnose disruption of the interosseous membrane during surgery for fracture of the radial head and to see if the test was reproducible. We studied 20 cadaveric forearms after excision of the radial head, ten with and ten without disruption of the interosseous membrane. On each forearm, we performed the radius joystick test: moderate lateral traction was applied to the radial neck with the forearm in maximal pronation, to look for lateral displacement of the proximal radius indicating that the interosseous membrane had been disrupted. Each of six surgeons (three junior and three senior) performed the test on two consecutive days. Intra-observer agreement was 77% (95% confidence interval (CI) 67 to 85) and interobserver agreement was 97% (95% CI 92 to 100). Sensitivity was 100% (95% CI 97 to 100), specificity 88% (95% CI 81 to 93), positive predictive value 90% (95% CI 83 to 94), and negative predictive value 100%). This cadaveric study suggests that the radius joystick test may be useful for detecting disruption of the interosseous membrane in patients undergoing open surgery for fracture of the radial head and is reproducible. A confirmatory study in vivo is now required.
    Journal of Bone and Joint Surgery - British Volume 10/2011; 93(10):1389-94. · 2.69 Impact Factor
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    ABSTRACT: We measured bone texture parameters of excised human femurs with a new device (BMA™). We also measured bone mineral density by DXA and investigated the performance of these parameters in the prediction of failure load. Our results suggest that bone texture parameters improve failure load prediction when added to bone mineral density. Bone mineral density (BMD) is a strong determinant of bone strength. However, nearly half of the fractures occur in patients with BMD which does not reach the osteoporotic threshold. In order to assess fracture risk properly, other factors are important to be taken into account such as clinical risk factors as well as macro- and microarchitecture of bone. Bone microarchitecture is usually assessed by high-resolution QCT, but this cannot be applied in routine clinical settings due to irradiation, cost and availability concerns. Texture analysis of bone has shown to be correlated to bone strength. We used a new device to get digitized X-rays of 12 excised human femurs in order to measure bone texture parameters in three different regions of interest (ROIs). We investigated the performance of these parameters in the prediction of the failure load using biomechanical tests. Texture parameters measured were the fractal dimension (Hmean), the co-occurrence matrix, and the run length matrix. We also measured bone mineral density by DXA in the same ROIs as well as in standard DXA hip regions. The Spearman correlation coefficient between BMD and texture parameters measured in the same ROIs ranged from -0.05 (nonsignificant (NS)) to 0.57 (p = 0.003). There was no correlation between Hmean and co-occurrence matrix nor Hmean and run length matrix in the same ROI (r = -0.04 to 0.52, NS). Co-occurrence matrix and run length matrix in the same ROI were highly correlated (r = 0.90 to 0.99, p < 0.0001). Univariate analysis with the failure load revealed significant correlation only with BMD results, not texture parameters. Multiple regression analysis showed that the best predictors of failure load were BMD, Hmean, and run length matrix at the femoral neck, as well as age and sex, with an adjusted r (2) = 0.88. Added to femoral neck BMD, Hmean and run length matrix at the femoral neck (without the effect of age and sex) improved failure load prediction (compared to femoral neck BMD alone) from adjusted r (2) = 0.67 to adjusted r (2) = 0.84. Our results suggest that bone texture measurement improves failure load prediction when added to BMD.
    Osteoporosis International 06/2011; 23(4):1311-6. · 4.04 Impact Factor

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