Microbiome and substances of abuse.

There is a growing amount of evidence showing a reciprocal relation between the gut microbiota and the brain. Substance use disorders (SUD), which are a major cause of preventable morbidity and mortality worldwide, have an influence on the gut microbiota and on the gut-brain axis. The communication between the microbiota and the brain exists through different pathways: (1) the immune response elicited by bacterial products, coupled with alterations of the intestinal barrier allowing these products to enter the bloodstream, (2) the direct and indirect effects of bacterial metabolites such as short chain fatty acids (SCFAs) or tryptophan on the brain, (3) and the hypothalamic-pituitary-adrenal (HPA) axis, whose peripheral afferents can be influenced by the microbiota, and can in turn activate microglia. Among substances of abuse, alcohol has been the subject of the greatest number of studies in this field. In some but not all patients suffering from alcohol-use-disorder (AUD), alcohol alters the composition of the gut microbiota and the permeability of the intestinal barrier, directly and through dysbiosis. It has also been well demonstrated that alcohol induces a peripheral inflammation; it is still unclear whether it induces a central inflammation, as there are contradictory results in human studies. In animal studies, it has been shown that neuroinflammation increases during alcohol withdrawal. Literature on opioids and stimulants is less numerous. Chronic morphine intake induces dysbiosis, increased intestinal permeability and a probable neuroinflammation, which could explain symptoms such as tolerance, hyperalgesia and deficit in reward behavior. Cocaine induces a dysbiosis and conversely the microbiome can modulate the behavioral response to stimulant drugs. Tobacco cessation is associated with an increase in microbiota diversity. Taken together, the findings of our narrative literature review suggest a bidirectional influence in the pathogenesis of substance use disorders.

Targeting the gut microbiota to treat alcoholic liver diseases: evidence and promises.

The human intestine is colonized by a variety of microbes that influence the metabolic responses, the immune system and the nervous system. Dietary patterns are important factors that shape the composition of the gut microbiota. Many animal models of alcohol exposure have highlighted the key role of the alcohol-induced gut microbiota alterations, leaky gut and translocation of microbial products in the development of alcoholic liver disease (ALD). However, in humans, there is no clear picture defining an "alcoholic microbiome", and the link between intestinal dysbiosis and ALD development is far from being understood. Although we do not comprehend all the mechanistic insights, clinical studies aiming at modulating the gut microbiota of alcoholic patients have shown some beneficial effects. Here we review the potential therapeutic effects of probiotics in ALD and give some clinical perspectives on the role of prebiotics and the use of fecal microbiota transplantation.

[What is the role of the gut microbiota in the development of alcohol use disorders?] / Troubles liés à l'usage d'alcool : et si l'addiction trouvait son origine dans l'intestin ?

Alcohol addiction is a complex and multifactorial disease influenced by social, psychological and biological aspects. The current pharmacological drugs used in the management of alcohol dependence have shown only a modest efficacy and the relapse rate remains high in this disease. Recently, the gut microbiota, a huge and dynamic ecosystem made up of billions of microorganisms living in our intestine, has been shown to regulate many important functions for human health. Indeed, the gut microbiota is known to influence our metabolism, our immune system as well as our nervous system with consequences for brain functions, mood and behaviour. We have shown that heavy and chronic alcohol consumption induced important changes in the composition of the gut microbiota. Furthermore, the microbial changes are associated with the severity of depression, anxiety and alcohol craving that are important factors predicting the risk of relapse. This suggests the existence of a gut-brain axis in alcohol dependence and supports the development of new therapeutic alternatives, targeting the gut microbiota, in the management of alcohol dependence.

L'addiction à l'alcool est une maladie complexe, impliquant à la fois des facteurs sociaux, psychologiques et biologiques. La prise en charge des patients alcoolo-dépendants est difficile car les médicaments actuels ont une efficacité limitée dans le maintien de l'abstinence, et le taux de rechute reste très élevé. Récemment, le microbiote intestinal, un écosystème constitué de milliards de micro-organismes vivant dans notre intestin, est devenu un acteur clé de la santé humaine. Il est connu pour réguler notre métabolisme, notre système immunitaire, mais également notre système nerveux, et donc notre comportement et notre humeur. Nos études récentes ont montré que la consommation abusive d'alcool entraîne des modifications importantes de la composition du microbiote intestinal. Nous avons également montré que ces altérations microbiennes étaient associées à la sévérité des symptômes de dépression, d'anxiété et d'appétence à l'alcool, suggérant ainsi l'existence d'un dialogue entre l'intestin et le cerveau. Ces résultats encouragent la recherche de nouvelles pistes thérapeutiques, ciblant le microbiote intestinal, dans le traitement de la dépendance à l'alcool.

Ten-year survival and complications of total knee arthroplasty for osteoarthritis secondary to trauma or surgery: A French multicentre study of 263 patients.

BACKGROUND: Previous surgical procedures raise technical challenges in performing total knee arthroplasty (TKA) and may affect TKA outcomes. Survival rates of TKA done after trauma or surgery to the knee have not been accurately determined in large populations. The objectives of this retrospective study in 263 patients with TKA after knee trauma or surgery and a follow-up of 10 years were to assess survival, functional outcomes, and the nature and frequency of complications. HYPOTHESIS: Knee trauma or surgery before TKA increases the risk of complications and decreases implant survival. MATERIAL AND METHODS: Two hundred and sixty-three patients (122 [47%] females and 141 [53%] males) underwent TKA between 2005 and 2009 at nine centres in France. Mean age at surgery was 61 years. The patients had knee osteoarthritis secondary to a fracture (n=66), osteotomy (n=131), or ligament injury (n=66). Mean time from trauma or surgery to TKA was 145 months (range, 72-219 months). RESULTS: Major complications were infection (n=12, 4.5%), skin problems (n=8, 3%), and stiffness (n=8, 3%). Ten-year survival to implant exchange for any reason was 89%±2.8%. Flexion range increased by 2.5°±17° (p=0.02) to a mean of 110° (range, 30° to 140°); extension range increased by 4°±7° (p<0.001) to a mean of -1.19 (range, -20° to 0°). Of the 263 patients, 157 (60%) reported little or no pain at last follow-up. Mean postoperative hip-knee-ankle angle was 179°±3.2° (range, 171°-188°). CONCLUSION: TKA performed after knee injury or surgery carries a risk of specific complications (infection, skin problems, and stiffness) and may have a lower survival rate compared to primary TKA. LEVEL OF EVIDENCE: IV, retrospective cohort study.

What are the risk factors for dislocation in primary total hip arthroplasty? A multicenter case-control study of 128 unstable and 438 stable hips.

INTRODUCTION: Dislocation after total hip arthroplasty (THA) is a leading reason for surgical revision. The risk factors for dislocation are controversial, particularly those related to the patient and to the surgical procedure itself. The differences in opinion on the impact of these factors stem from the fact they are often evaluated using retrospective studies or in limited patient populations. This led us to carry out a prospective case-control study on a large population to determine: 1) the risk factors for dislocation after THA, 2) the features of these dislocations, and 3) the contribution of patient-related factors and surgery-related factors. HYPOTHESIS: Risk factors for dislocation related to the patient and procedure can be identified using a large case-control study. PATIENTS AND METHODS: A multicenter, prospective case-control study was performed between January 1 and December 31, 2013. Four patients with stable THAs were matched to each patient with a dislocated THA. This led to 566 primary THA cases being included: 128 unstable, 438 stable. The primary matching factors were sex, age, initial diagnosis, surgical approach, implantation date and type of implants (bearing size, standard or dual-mobility cup). RESULTS: The patients with unstable THAs were 67±12 [37-73]years old on average; there were 61 women (48%) and 67 men (52%). Hip osteoarthritis (OA) was the main reason for the THA procedure in 71% (91/128) of the unstable group. The dislocation was posterior in 84 cases and anterior in 44 cases. The dislocation occurred within 3 months of the primary surgery in 48 cases (38%), 3 to 12 months after in 23 cases (18%), 1 to 5years after in 20 cases (16%), 5 to 10years after in 17 cases (13%) and more than 10years later in 20 cases. The dislocation recurred within 6 months of the initial dislocation in 23 of the 128 cases (18%). The risk factors for instability were a high ASA score with an odds ratio (OR) of 1.93 (95% CI: 1.4-2.6), neurological disability (cognitive, motor or psychiatric disorders) with an OR of 3.9 (95% CI: 2.15-7.1), history of spinal disease (lumbar stenosis, spinal fusion, discectomy, scoliosis and injury sequelae) with an OR of 1.89 (95% CI: 1.0-3.6), unrepaired joint capsule (all approaches) with an OR of 4.1 (95% CI: 2.3-7.37), unrepaired joint capsule (posterior approach) with an OR of 6.0 (95% CI: 2.2-15.9), and cup inclination outside Lewinnek's safe zone (30°-50°) with OR of 2.4 (95% CI: 1.4-4.0). DISCUSSION: This large comparative study isolated important patient-related factors for dislocation that surgeons must be aware of. We also found evidence that implanting the cup in 30° to 50° inclination has a major impact on preventing dislocation. LEVEL OF EVIDENCE: Level III; case-control study.

The link between inflammation, bugs, the intestine and the brain in alcohol dependence.

In recent years, some new processes have been proposed to explain how alcohol may influence behavior, psychological symptoms and alcohol seeking in alcohol-dependent subjects. In addition to its important effect on brain and neurotransmitters equilibrium, alcohol abuse also affects peripheral organs including the gut. By yet incompletely understood mechanisms, chronic alcohol abuse increases intestinal permeability and alters the composition of the gut microbiota, allowing bacterial components from the gut lumen to reach the systemic circulation. These gut-derived bacterial products are recognized by immune cells circulating in the blood or residing in target organs, which consequently synthesize and release pro-inflammatory cytokines. Circulating cytokines are considered important mediators of the gut-brain communication, as they can reach the central nervous system and induce neuroinflammation that is associated with change in mood, cognition and drinking behavior. These observations support the possibility that targeting the gut microbiota, by the use of probiotics or prebiotics, could restore the gut barrier function, reduce systemic inflammation and may have beneficial effect in treating alcohol dependence and in reducing alcohol relapse.

Extracting recurrent scenarios from narrative texts using a Bayesian network: application to serious occupational accidents with movement disturbance.

A probabilistic approach has been developed to extract recurrent serious Occupational Accident with Movement Disturbance (OAMD) scenarios from narrative texts within a prevention framework. Relevant data extracted from 143 accounts was initially coded as logical combinations of generic accident factors. A Bayesian Network (BN)-based model was then built for OAMDs using these data and expert knowledge. A data clustering process was subsequently performed to group the OAMDs into similar classes from generic factor occurrence and pattern standpoints. Finally, the Most Probable Explanation (MPE) was evaluated and identified as the associated recurrent scenario for each class. Using this approach, 8 scenarios were extracted to describe 143 OAMDs in the construction and metallurgy sectors. Their recurrent nature is discussed. Probable generic factor combinations provide a fair representation of particularly serious OAMDs, as described in narrative texts. This work represents a real contribution to raising company awareness of the variety of circumstances, in which these accidents occur, to progressing in the prevention of such accidents and to developing an analysis framework dedicated to this kind of accident.

Evora® chromium-cobalt dual mobility socket: results at a minimum 10 years' follow-up.

INTRODUCTION: The Evora chromium-cobalt alloy dual mobility socket claims to display a large articulation tribology different from that of stainless steel models, limiting the risk of intraprosthetic dislocation and wear. The present study reports a minimum of 10years' follow-up in a multicenter prospective series of 200 sockets previously reported on at 5years. HYPOTHESIS: The use of chromium-cobalt in dual mobility sockets provides a low rate of failure at 10years, especially as regards to osteolysis and intraprosthetic dislocation. MATERIALS AND METHODS: Two hundred hydroxyapatite-coated molded chromium-cobalt sockets without titanium interface were implanted without cement in 194 patients with a mean age of 70 years (range, 32-91 years). Clinical results were assessed on Postel Merle d'Aubigné and Harris scores, plain radiographs and survival analysis. RESULTS: At a mean 11 years' follow-up (10-13 years), 56 patients had died and 31 were lost to follow-up. Four underwent surgical revision (3 femoral components, and 1 socket for migration at 9 years with complete disappearance of the hydroxyapatite). A total of 109 implants were analyzable in 107 patients with a mean age of 81 years (55-93 years). At follow-up, the mean Harris score was 90 (75-96) and the PMA score 16.3 (14-18). There were no cases of loosening (except for the case reoperated on at 9 years) and no acetabular radiolucency or cysts. There were 2 cases of non-evolutive femoral radiolucency and 10 of femoral granuloma, involving head size > 22 mm (P<0.0001) and a cemented titanium stem (P=0.004) as risk factors. There were no dislocations in the large or small articulation. Ten-year survival was 99% (95% CI: 97.3%-100%) with socket revision as censorship criterion. DISCUSSION: The absence of dislocation in both small and large articulations confirmed the efficacy of the dual mobility concept and suggested an advantage for chromium-cobalt sockets in reducing the rate of intraprosthetic dislocation and preventing blockage of the large articulation by a better performance in the friction couple. Granulomas were associated with wear in cemented titanium stems and with heads greater than 22 mm in diameter. Ten-year survival was 99% (censorship criterion: revision for socket failure); there was, however, one case of socket loosening with disappearance of the hydroxyapatite, indicating that surveillance should be continued in this cohort.

Durom hip resurfacing system: retrospective study of 644 cases with an average follow-up of 34 months.

INTRODUCTION: The performance of second-generation metal-on-metal bearings has led to the reintroduction of hip resurfacing. The goal of this multicentre study was to evaluate the short-term radiological and clinical outcomes with the Durom hip resurfacing system. HYPOTHESIS: The Durom hip-resurfacing system will have similar results to other hip resurfacing systems and traditional hip arthroplasty implants. MATERIALS AND METHODS: In the four participating centers, 580 patients (406 men, 174 women) and 644 hips were included. The average patient age was 48 years (range 16-77). A posterolateral surgical approach was used in 357 cases; a Hardinge-type approach was used in 182 cases and a Rottinger-type approach in 105. RESULTS: After an average follow-up of 34 months, 31 hips (4.8%) had been revised. The reasons for revision were the following: 10 (1.6%) neck fracture (seven with Rottinger operative approach, one with Hardinge approach and one with posterolateral approach); 12 (1.9%) femoral loosening (four with lateral approach and eight with posterolateral approach); four (0.6%) acetabular cup migration; three (0.5%) unexplained pain; one (0.2%) adverse reaction to metal debris; one (0.2%) infection. Four hips (0.6%) dislocated but without recurrence - all were operated using the Hardinge approach. The 613 hips that were not operated on again had satisfactory clinical results; the Merle d'Aubigné score was 17.2 (range 12-18) and the WOMAC score was 91 (range 20-100). The five-year survival rate was 91% (95% CI: 87-94%). Based on radiographs, the average cup inclination was 44.4° (range 30 to 70°). The femoral offset was reduced by an average of 2.4mm (-31 to 23 mm) and the leg length had increased by an average of 0.8mm (-15 to 19 mm) relative to the other side, which was prosthesis-free. None of the non-revised implants showed any signs of loosening. DISCUSSION: This multicentre evaluation revealed that the Durom revision rate was slightly higher than the rate with other hip resurfacing systems and traditional total hip arthroplasty. Although the Durom system displayed excellent tribological performance, the differences relative to other implants may be attributed to the challenges associated with impaction, related to the geometry and design of the cup, and to precarious primary fixation. The choice of surgical exposure and implantation technique was an important factor in the survival of the implant. LEVEL OF PROOF: Level IV - Retrospective study.

Sorption of nickel and cobalt ions onto cobalt and nickel ferrites.

The corrosion of the metal parts in the primary circuit of pressurized water reactors leads to the release of colloidal particles (NiFe(2)O(4), CoFe(2)O(4), NiO, Ni...) and ionic species (Co, Ni, Cr...). Particles can interact with ionic species in the primary medium, contributing to their transport and to their deposition onto surfaces outside the neutron flux generating radioactive contamination. Sorption and zetametry experiments at 25 °C were performed on the Ni(2+)/CoFe(2)O(4) and Co(2+)/NiFe(2)O(4) systems in order to determine the behaviour of corrosion products in the fluid of the primary circuit. Sorption appears as surface complexation starting from pH 6 and is followed by precipitation of hydroxide above pH 7.5. Complexation and solubility constants were obtained from the modelling of sorption curves. The two oxide systems present a very similar sorption behaviour, but some differences, due to their different isoelectric points, could be observed on zetametric measurements.

A 5-aza-2'-deoxycytidine/valproate combination induces cytotoxic T-cell response against mesothelioma.

Malignant pleural mesothelioma (MPM) is an aggressive tumour with a limited response to conventional therapy. The aim of this study was to evaluate the anticancer effect of a DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine (5-azaCdR), and two histone deacetylase inhibitors, valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA). Human mesothelioma cells were treated with each epigenetic drug, either alone or in combinations. The cytotoxic effects on treated cells and the expression of specific tumour antigens were evaluated. The recognition of treated cells by a specific CD8+ T-cell clone was also measured. Additionally, the effect of combined treatments was tested in a murine model of mesothelioma. We showed that VPA and SAHA synergised with 5-azaCdR to kill MPM cells and induce tumour antigen expression in the remaining living tumour cells. As a consequence, tumour cells expressing these antigens were recognised and lysed by specific CD8+ cytotoxic T-cells. In vivo, treatment with 5-azaCdR/VPA inhibited tumour growth, and promoted lymphocyte infiltration and an immune response against tumour cells. Appropriate epigenetic drug combinations, in addition to inducing mesothelioma cell death, also affect the immunogenic status of these cells. This property could be exploited in clinical investigations to develop MPM treatments combining chemotherapeutic and immunotherapeutic approaches.

Dual mobility design use in preventing total hip replacement dislocation following tumor resection.

INTRODUCTION: Total hip replacement (THR) following hip tumor resection incurs a high risk of dislocation. We assessed the incidence of dislocation associated with use of a dual mobility cup,and the functional results achieved. HYPOTHESIS: Use of a dual mobility cup would reduce the risk of THR instability following hip tumor resection. MATERIAL AND METHODS: We analyzed dislocation rates in a retrospective series of 71 dual mobility cup THRs implanted following the resection of a tumor hip condition: 33 primary bone tumors and 38 bone metastases. The presenting pathology was diagnosed anatomically, and surgery classified in terms of adopted abductor system strategy. Functional results were assessed in terms of pain (analgesia on the World Health Organisation [WHO] scale), assisted walking and Musculoskeletal Tumor Society (MSTS) score. RESULTS: An overall rate of 9.8% dislocation was observed, taking into account all etiologies and contexts together. More precisely, this rate resulted from a compound figure of 5.2% in bone metastasis and 15% in primitive bone tumor. Dislocation risk depended lesson etiology than on the surgical management of the abductor system, being 3.5% in the case of abductor conservation, 9.5% in the case of abductor sectioning/reinsertion, and 18%in case of gluteus medius muscle or nerve resection. Functional improvement was consistently observed, especially in bone metastasis. At the maximal follow-up, 32 patients were not using analgesics, six were taking WHO class III analgesics, 10 class II and 23 class I. Mean MSTS score was 68.1% +/- 23.5% in bone metastasis and 59.6% +/- 17.5% in primary bone tumor.Fourteen patients could walk without assistance, 33 with a single cane, 15 with two canes and eight with a walker; one patient had not been able to resume walking. DISCUSSION: In these indications, dual mobility cups use lead to lower dislocation rates than those reported in the literature. It proved especially effective in the case of bone metastasis and consolidation surgery. In the case of primary bone tumor, it failed to prevent dislocation following acetabular resection, especially when involving the abductor muscles and/or abductor innervation, although it provided lower dislocation rates, comparable to those experienced with other techniques, when applied to limited resection. LEVEL OF EVIDENCE: IV. Retrospective therapeutic study.

Rhein, the metabolite of diacerhein, reduces the proliferation of osteoarthritic chondrocytes and synoviocytes without inducing apoptosis.

OBJECTIVE: The aim of this study was to determine the effects of pharmacologically relevant concentrations of rhein (1,8-dihydroxy-3-carboxyanthraquinone) on the cell proliferation rate of human chondrocytes and synoviocytes. METHODS: Cultures of human osteoarthritic synoviocytes and chondrocytes were incubated with 10(-6), 10(-5), and 10(-4) M rhein. [3H]thymidine incorporation was used to determine rhein proliferative effects after incubation periods of 24 h, 48 h, and 1 week. The cytotoxicity of the drug was assayed with a nonradioactive assay kit. Nuclear extracts were used to detect variations in cell-cycle proteins (p21, p27, and cyclin D1) by Western blotting. The effect of rhein on apoptosis was investigated by measurement of caspase-3/7 activity and DNA fragmentation. RESULTS: Rhein was found to downregulate the proliferation rate of both chondrocytes and synoviocytes, two-fold for 10(-5) M rhein and five- to six-fold for 10(-4) M rhein. No cytotoxicity of the drug was observed. Rhein (10(-4) M) decreased caspase-3/7 activity and did not induce DNA fragmentation. Western blots showed that 10(-4) M rhein increased the expression of p21 and/or p27, but not that of cyclin D1. CONCLUSIONS: Rhein has previously been shown to reduce the interleukin (IL)-1beta deleterious effects on osteoarthritis (OA) cartilage through inhibition of the expression of degrading enzymes. Here, rhein was also found to inhibit proliferation of both synoviocytes and chondrocytes, suggesting that the drug may decrease the development of the inflammatory synovial tissue that accompanies joint pathologies. Both its anti-catabolic and anti-proliferative effects may explain its beneficial effect in the treatment of joint diseases.

Results of the Evora dual-mobility socket after a minimum follow-up of five years.

PURPOSE OF THE STUDY: Dislocation is a well-known complication of total hip arthroplasty. The risk can be reduced to one or two cases per thousand using a dual-mobility cup. The survival rate achieved with the Bousquet implant is 95% at 10 years. The complications with this implant are early mobilization and inguinal pain. An overly-large cup and insufficient primary and secondary fixation can be implicated. The design of the original implant was later modified to limit these early complications. The purpose of this study was to check the validity of these design changes. PATIENTS AND METHODS: The chromium-cobalt moulded cementless cup was used. The outer surface of this cup presents large geometric striations and is coated with hydroxyapatite. The cup has the shape of a 180 degrees half sphere and a posterior wall prolongation measuring 6.5mm. Three mechanisms were used for the primary fixation: an asymmetrical growth ring, four anchorage stems and a superior screw. Two hundred cementless cups were implanted in 194 patients. The femoral piece was a Charnley stainless-steel implant (n=139), a titanium SEM implant (n=59) or another implant (n=12). Cement was used for femoral fixation in 193 implantations. The series included 97 women and 103 men with osteoarthritis (n=180), necrosis (n=16) and surgery for fracture and primary arthroplasty (n=9). The Harris and Postel-Merle-d'Aubigné scores were noted. Eight radiographic criteria were analyzed to assess the position of the cup and the radiological course of the interface. RESULTS: The mean follow-up was six years and the minimum was five years. The mean age at surgery was 70 years (range, 32 to 91). At last follow-up, 17 patients had died, eight were lost to follow-up and five were bedridden. Three patients underwent revision surgery. Thus, this analysis included 170 prostheses followed for more than five years (mean, six years; range, five to seven years). The Harris score improved from 48 to 92 and the Postel-Merle-d'Aubigné score from 2/5/4 to 5.8/5.9/5.5 (range, 4 to 6/5 to 6/1 to 6). None of the patients complained of anterior pain during active hip flexion in supine position (related to ilio-psoas irritation). Cup inclination was 46 degrees on average (range, 62 to 22 degrees ). Medialization, lateralization or ascension greater than 10mm from the center of rotation was not observed on the postoperative films. At the last follow-up, no measurable mobilization or migration could be identified on plain X-rays. Radiolucent lines, condensations and bony defects around the cup, when visible postoperatively, were not found on the last follow-up X-rays. There were two cemented femoral pieces that developed a radiolucent line in the nonspecific metaphyseal area. There were no cases of granuloma and no cam effect. Three patients underwent revision for femoral loosening, fracture of the femur below the prosthesis and hematogenous infection. There were no cases of dislocation. DISCUSSION: Changing the design of the implant to modify its volume, material and primary fixation has eliminated the early mobilizations and inguinal pain described for the original Bousquet cup. These options have not had any deleterious effect on prosthesis stability. The question of long-term wear remains an important problem and requires optimization: a neck as thin as possible, optimized surfacing, elimination of laser marks, extraction leads and head skirts.

Studying work practices: a key factor in understanding accidents on the level triggered by a balance disturbance.

Accidents on the level (AOL) rank second amongst the most numerous and serious occupational accidents with days lost in France and are a major health and safety problem in every sector of activity. The case study described in this paper was conducted at a metallurgical company with 300 employees. The aims of this work were dual: 1) to extend the general knowledge required for preventing these accidents; 2) to propose prevention measures to this company. Existing data on company occupational accidents were gathered and analysed to identify a work situation that appeared likely to cause AOL. This work situation was analysed in detail. Several risk factors were identified within this work situation, by way of interviews with 12 operators. These risk factors concerned various dimensions of the work situation, particularly its physical dimension (e.g. templates structure) and organisational dimension (e.g. parts availability). Interviews were conducted, focusing on risk factors perceived by operators and involving allo-confrontations based on accounts of four AOL occurring in this situation. Allo-confrontations were interviews confronting operators with a risk occupational situation that was accidental for one of their colleagues, the latter being absent from the interview. Results highlighted the fact that the work practices implemented are key factors in understanding these accidents. This study underlines the role of work practices in AOL causality and prevention. It also provides explanations associated with various work situation dimensions involving adoption of more or less safe work practices. AOL are serious and frequent in occupational situations. Injury claims analysis and interviews in an industrial company emphasise the specific characteristics of an occupational situation and of prevention actions forming the basis of an intervention. The need for a better understanding of factors affecting work practice is highlighted in relation to research.

[Results of the Evora dual mobility socket: five years follow-up]. / Résultat à cinq ans de la cupule à double mobilité Evora.

PURPOSE OF THE STUDY: Dislocation is a well-known complication of total hip arthroplasty. The risk can be reduced to one or two cases per thousand using a double mobility cup. The survival rate achieved with the Bousquet implant is 95% at 10 years. The complications with this implant are early mobilization and inguinal pain. An overly large cup and insufficient primary and secondary fixation can be implicated. The design of the original implant was later modified to limit these early complications. The purpose of this work was to check the validity of the changes made. PATIENTS AND METHODS: The chromium-cobalt moulded cup was used. The outer surface of this cup presents large geometric striations and is coated with hydroxyapatite. The cup has the shape of a half sphere of 180 degrees and a posterior wall prolongation measuring 6.5mm. Three mechanisms were used for the primary fixation: an asymmetrical growth ring, four anchorage stems, and a superior screw. Two hundred cups were implanted in 194 patients. The femoral piece was a Charnley stainless steel implant (n=139), a titanium SEM implant (n=59) or another implant (n=12). Cement was used for 193 implantations. The series included 97 women and 103 men with osteoarthritis (n=180), necrosis (n=16), surgery for fracture and primary arthroplasty (n=9). The Harris and Postel-Merle-d'Aubigné scores were noted. Eight radiographic criteria were analyzed to assess the position of the cup and the radiological course of the interface. RESULTS: Mean time to surgery was six years. Mean age at surgery was 70 years (range: 32-91) and varied depending on the operators from 67 to 73 years. At last follow-up: 17 patients had died, eight were lost to follow-up and five were bedridden. Three patients underwent revision surgery. Thus, this analysis included 170 prostheses followed for more than five years (mean: six years, range: 5-7 years). The Harris score improved from 48 to 92 and the Postel-Merle-d'Aubigné score from 2/5/4 to 5.8/5.9/5.5 (range: 4-6/5-6/1-6). None of the patients complained of anterior pain during hip flexion against resistance. Cup inclination was 46 degrees on average (range: 62-22 degrees ). Medialization, lateralization or ascension greater than 10mm of the centre of rotation was not observed on the postoperative films. At last follow-up, no measurable mobilization or migration could be identified on plain X-rays. Lucent lines, condensations and bony defects around the cup, when visible postoperatively, were not found on the last follow-up X-rays. There were two cemented femoral pieces, which developed a lucent line in the nonspecific metaphyseal area. There were no cases of granuloma and no cam effect. Three patients underwent revision for femoral loosening, fracture of the femur below the prosthesis, and hematogenous infection. There were no cases of dislocation. DISCUSSION: Changing the design of the implant to modify its volume, material and primary fixation has eliminated the early mobilizations and inguinal pain described for the original Bousquet cup. These options have not had any deleterious effect on prosthesis stability. The question of long-term wear remains an important problem and requires optimization: a neck as thin as possible, optimized surfacing, elimination of laser marks, extraction leads, head skirts.