Prognostic factors to succeed in surgical treatment of chronic acromioclavicular dislocations

AbstractIntroductionTreatment of chronic acromioclavicular joint dislocation (ACJD) remains a poorly known and controversial subject. Given the many surgical options, it is not always easy to determine which steps are indispensable.MethodsThis article reports a multicenter prospective study. The clinical and radiological follow-up involved a comparative analysis of the preoperative and postoperative data at 1 year, including pain (visual analogue scale), subjective functional incapacity (QuickDASH), and the objective Constant score, as well as a comparative analysis of vertical and horizontal movements measured on simple x-rays.ResultsBased on a series of 140 operated ACJDs, we included 24 chronic ACJDs. The mean time to surgery was 46 weeks (range, 1 month to 4 years). The patients’ mean age was 41 years, with a majority of males (75%), 72% of whom participated in recreational sports. Professionally, 40% of the subjects had jobs involving manual labor. We noted 40% grade III, 24% grade IV, and 36% grade V injury according to the Rockwood classification. In 92% of cases, coracoclavicular stabilization was provided by a double button implant, reinforced with a biological graft in 88% of the cases. In 29%, millimeters to centimeters of the distal clavicle were resected and acromioclavicular stabilization was associated in 54%. We observed complications in 33% of the cases. At 1 year postoperative, 21 patients underwent clinical and radiological follow-up (87.5%). Only 35% of the patients were satisfied or very satisfied, whereas 100% of them would recommend the operation. Full-time work was resumed in 91% of the cases and all sports could be resumed in 86%. The pre- and postoperative values at 1 year changed as follows: the mean Constant score improved from 61 to 87 (p=0.00002); the subjective QuickDASH score decreased from 41 to 9 (p=0.00002); and radiologically significant reduction of the initial displacement was observed in the vertical plane (p<10−3) and the horizontal plane (p=0.022).ConclusionIn this study, the favorable prognostic factors found were: time to surgery less than 3 months (p=0.02), associated acromioclavicular stabilization, and postoperative immobilization with a sling extended to 6 weeks. However, resection of the distal clavicle did not influence the final result.Level of proofLevel II prospective non-randomized comparative study

The influence of microstructure and composition on the plastic behaviour of dual-phase steels

This paper presents a systematic experimental study of the relative contributions of the martensite volume fraction, morphology and carbon content to the overall strength and ductility of dual-phase steels. To this end, model dual-phase steels combining three volume fractions of martensite, three martensitic carbon contents, and three arrangements of the phases were generated by suitable control of the heat treatments. The microstructures include long and short elongated, as well as equiaxed martensitic islands. The yield and tensile strengths increase with both the amount of martensite and its carbon content. The ductility in general increases with the volume fraction of martensite at constant martensitic carbon content, and conversely increases with the martensitic carbon content for a fixed volume fraction of martensite. Departure from the general trend is observed for combinations of a large volume fraction of martensite with a large martensitic carbon content, and is attributed to damage-induced softening or fracture. Specimens with long elongated martensite demonstrate an improved ductility compared to other microstructures. The plastic flow properties were further investigated by relying on a non-linear homogenization model which explicitly accounts for the microscopic parameters. The micromechanical model captures reasonably well the tensile behaviour for the complete range of martensite carbon contents and volume fractions

Characterization of Type I and IV Collagens by Raman Microspectroscopy: Identification of Spectral Markers of the Dermo-Epidermal Junction

Abstract. Type I and IV collagens are important constituents of the skin. Type I collagen is found in all dermal layers in high proportion, while type IV collagen is localized in the basement membrane of the dermo-epidermal junction (DEJ). These proteins are strongly altered during aging or cancer progression. Although they possess amino acid compositions which, are close, they present also important structural differences inducing specific physicochemical properties. Raman spectroscopy is based on a nondestructive interaction of the light with the matter. This technique permits to probe the intrinsic molecular composition of the samples without staining or particular preparation. The aim of our research is to study the correlation between the molecular conformations of type I and IV collagens and their Raman features. We showed that signals specific of each protein can be revealed and that they translate structural differences between the two collagens. From this collagens spectral characterization, the analysis of skin sections also permitted to identify spectral markers of dermis, epidermis, and epidermis/dermis interface. These preliminary results represent basic data for further studies, particularly to probe skin molecular alterations induced by chronologic aging

Refined dual-phase steel from cold-rolled martensite with 3.5wt% Mn.

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Elaboration of a French version of the Duke Activity Status Index questionnaire and performance to predict functional capacity

International audienceBACKGROUND: Guidelines recommend detecting poor functional capacity (VO(2max) \textless 14 ml.kg(-1).min(-1)) to assess preoperative cardiac risk. This screening is performed via a cardiopulmonary exercise test (CPET), the self-reported inability to climb two flights of stairs, or the use of the Duke Activity Status Index (DASI) questionnaire, which has shown a significant correlation with VO(2max) and postoperative outcomes. The objectives of the present study were: 1) to create a French version of the DASI questionnaire (FDASI); 2) to assess its diagnostic performance in predicting functional capacity. METHODS: Consecutive adult patients undergoing CPET for medical or preoperative evaluation were prospectively included between May 2020 and March 2021. All patients were asked to complete FDASI as a self-questionnaire and report their inability to climb two flights of stairs. RESULTS: 122 patients were included. Test-retest reliability was 0.88 and 23 (19%) patients experienced a VO(2)(max) \textless 14 ml.kg(-1.)min(-1). There was a significant positive relationship between FDASI and VO(2max): r(2) = 0.32; p \textless  0.001. ROC(AUC) was 0.81 [95%CI: 0.73-0.89]. The best FDASI score threshold was 36 points, leading to sensitivity and specificity values of 87% [74-100] and 68% [56-79], respectively. Besides, sensitivity and specificity were 35% [17-56] and 92% [86-97] for the self-reported inability to climb two flights of stairs. CONCLUSION: A FDASI score of 36 represents a reliable threshold the clinicians could routinely use to identify patients with a VO(2max) \textless 14 ml.kg(-1.)min(-1). FDASI could advantageously replace the self-reported inability to climb two flights of stairs

Influence of martensite volume fraction and hardness on the plastic properties of ferrite-martensite dual-phase steels

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