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The use of the composite pultruded materials is increasing due to the particular characteristics of lightness, ease of installation, high corrosion resistance and, finally, lower maintenance costs....

Background The main aim of this study was to evaluate the performance of magnetic resonance imaging (MRI) and interobserver agreement in the identification of the comma sign. The second objective was to look for a correlation between the comma sign and the detachment of the superficial fascia of the subscapularis. Materials and methods Two radiologists, blinded to the arthroscopic findings, retrospectively assessed the magnetic resonance images of 110 shoulders and were asked to assess the presence of the comma sign and the intact subscapularis fascia. The inter-reader agreement and the MRI performance values for detection of the comma sign were calculated. In addition, the association between the intact superficial subscapularis fascia and the comma sign was evaluated. Results The agreement between the 2 radiologists was perfect. The following values were obtained: sensitivity, 90.9%; specificity, 98.8%; positive predictive value, 95.2%; negative predictive value, 97.7%; and accuracy, 97.2%. No association between the comma sign and subscapularis fascia lesions was found. Conclusion MRI appears to be a reliable method for preoperative assessment of the comma sign. The comma sign appears not to be formed by the detached subscapularis fascia.

Unrecognized posterior shoulder dislocation with a concomitant humeral head fracture affects joint function and no consensus exists regarding treatment. The present study analyses clinical and radiographic outcomes of a novel arthroscopic technique for reducing chronic locked posterior shoulder dislocation associated with subscapularis remplissage. The study comprises a retrospective analysis of consecutive chronic posterior locked shoulders (CPLS) with minimum 2-years follow-up of patients who had undergone McLaughlin technique arthroscopic modification for the treatment of CPLS with a reverse Hill–Sachs lesion. Active range of motion (ROM), Western Ontario (WOSI) and Constant Score (CS), were evaluated pre- and postoperatively. Plain radiographs and magnetic resonance imaging (MRI) scans were collected pre- and post-operatively, recording bone defect, osteoarthritis, cuff integrity/fatty infiltration, and the grade of filling of the reverse Hill-Sachs. Twelve male patients with a mean follow-up of 37.3 months ± 10.5 (range, 24–58) were included. Mean WOSI and CS scores improved from 41 to 92 and 28 to 94 points, respectively. ROM measurements all had significantly increased at final follow-up, with no significant differences in arm rotation. No defects were left unfilled at final MRI examination. The results of this uncontrolled study with a limited number of patients confirm that arthroscopic reduction and subscapularis remplissage is a highly effective and satisfactory treatment method resulting in no shoulder rotation deficits. Level IV.

Purpose The aim of this study was to describe an advanced total knee arthroplasty (TKA) fast-track programme and determine discharge parameters during hospitalisation, as well as patient satisfaction, outcomes and complications within the first 12 months after surgery. Methods This prospective study was based on patients selected consecutively for primary elective TKA, undergoing surgery between 2014 and 2017 in an established fast-track setting. Hospitalisation-related parameters were collected: demographics, body mass index (BMI), surgical time, ischaemia time, haemoglobin values, blood transfusions, length of stay, weight-bearing and stair-climbing time, opioid administration, preoperative and discharge loss of extension and maximum active flexion of the knee, visual analogue scale (VAS), 12-month follow-up satisfaction rate and range of motion, any complications, hospital re-admission and re-operation within the first 12 months. Differences were determined using t-tests. Results A total of 704 total knee replacements implanted in 481 patients were included in the study and 223 patients had a bilateral TKA. Their mean age was 69.8 years (range 57–88 years). At the 12-month follow-up, 623 patients (88.5%) reported being satisfied or very satisfied and 15 (2.1%) were dissatisfied with their TKA, mean active flexion and loss of extension were 104.4° and 2.3°, respectively. A total of 15 complications occurred (two percent): five painful knees, three knee stiffness, three haematomas, two infections, one hospital re-admission and one deep venous thrombosis. No cases of pulmonary embolism and death related to surgery were reported. Conclusion The study reports on an advanced fast-track programme for TKA with a low incidence of surgery- and hospitalisation-related issues and complications and without any severe adverse events during the first year. On average, the fast-track programme had a short length of stay, an early recovery of weight-bearing, knee mobility, pain control and a high satisfaction rate, accompanied with an acceptable 12 month range of motion.

In this paper a methodology for studying the mechanical behaviour of complex structures made of GFRP structural members joined by means of adhesive connections and subject to variable intensity loads is presented. The fundamental equations are derived by an asymptotic approach applied on composite structures made of two elastic solids bonded together by a third thin one represented by a thin layer with a nonlinear behaviour . The adhesive layers are considered micro cracked according to the Kachanov’s assumptions. Within this framework, to calibrate the parameters of the imperfect interface model, the mechanical properties and damage evolution of an epoxy adhesive have been experimentally evaluated under cyclic loadings. The experimental tests have been performed on aluminium cylinders considering different thicknesses of adhesive. The experimental results evidence how the adhesive thickness influences the strength, stiffness and consequently the initial damage parameter (initial cracks) of the bonded connections. Finally, the robustness and accuracy of the imperfect interface model is demonstrated by the excellent comparison with experimental results of a GFRP hollow column to built-up beam adhesive connection, under static, cyclic and fatigue loads using a description of damage evolution.

The incidence of fragility fractures of the acetabulum (FFA) is constantly increasing. Generally, these fractures are related to a fall on the greater trochanter involving the anterior column. The management of FFA is extremely difficult considering both patients’ comorbidities and poor bone quality. Both non-operative and several operative treatment protocols are available, and the choice among them is still ambiguous. The proposed surgical techniques for FFA [namely open reduction and internal fixation (ORIF), percutaneous fixation and total hip arthroplasty (THA)] are associated with a high complication rate. The treatment with the higher early mortality is the ORIF + THA, while the one with the lowest is the non-operative. However, at longer follow-up, this difference dreadfully change is becoming the opposite. Frequently ORIF, percutaneous fixation, and non-operative treatment need a subsequent re-operation through a THA. This latter could be extremely difficult, because of poor bone quality, acetabular mal union/non-union, bone gaps and hardware retention. However, the outcomes of each of the proposed treatment are mostly poor and controverted; therefore, a comprehensive patient evaluation and an accurate fracture description are required to appropriately manage acetabular fracture in the elderly.

Background This study aims to identify risk factors related to postoperative instability after reverse shoulder arthroplasty and evaluate the modalities and results of treatments in a large series of patients, with medium to long-term follow-up. Methods Retrospective multicenter series of 1035 consecutive Grammont type reverse shoulder arthroplasties implanted between 1992 and 2010. 19.9% had a reverse shoulder arthroplasty with bony lateralization on the glenoid side. Patients were reviewed and radiographed with minimum five years’ follow-up. Results At a mean follow-up of eight years, the overall rate of postoperative instability was 3.0%. Instability was more frequent in case of reverse shoulder arthroplasty for revision surgery, in younger patients, in case of scapular notching, and tuberosity resorption. Lateralized reverse shoulder arthroplasties were associated with a lower instability rate. A reoperation to restore stability was needed in 70% of cases. The improvement in Constant Score was lower in patients with unstable reverse shoulder arthroplasties when compared to stable reverse shoulder arthroplasties. Conclusions Younger patients are at higher risk for instability after Grammont type reverse shoulder arthroplasty implantation. Conversely, lateralized reverse shoulder arthroplasties resulted protective. When conservative treatment had failed, shoulder stability can be obtained with reoperation or prosthetic revision (needed in 70% of the cases), but to the price of lower functional results.

Background Scapular fractures after reverse shoulder arthroplasty (RSA) are an increasingly reported complication. Information is missing regarding midterm to long-term follow-up consequences. The aim of this study was to determine the rate of scapular fracture (acromial base and spine) after Grammont-style RSA and to report functional and radiographic results of patients with a minimum 5-year follow-up. Materials and methods We retrospectively reviewed 1953 Grammont-style RSAs in 1745 patients in a multicenter study. Of these, 953 patients (1035 RSAs) had minimum 5-year follow-up for functional and radiographic assessment (anteroposterior and scapular Y views. Results Twenty-six patients (1.3%) had sustained a scapular fracture; of these, 19 (10 acromial base and 9 spine fractures) had minimum 5-year follow-up and were reviewed at a mean follow-up of 97 months. Three patients (15.8%) were diagnosed at the last follow-up after an undiagnosed fracture. There were 3 traumatic cases (15.8%) and 13 (68.4%) without antecedent trauma. These 16 patients underwent nonoperative treatment. The fracture was healed in 8 (4 acromion and 4 spine). The average active forward elevation was 109° (range, 50°-170°), and the Constant score was 47.0 points (range, 8-81 points). Conclusions Scapular fractures after Grammont-style RSAs are rare (1.3%) but remain a concern. These fractures occur mainly in the early postoperative 6 months. Immobilization with an abduction splint frequently resulted in nonunion or malunion. Final functional outcomes are poor regardless of acromial or spine fracture compared with primary RSA without fracture.

Scapular stress fractures after reverse shoulder arthroplasty (RSA) are a potentially serious complication with modern lateralized and onlay implants. The aim of this study was to report the scapular spine stress fracture rate after RSA with an onlay, 145° humeral stem, analyzing potential fracture risk factors and clinical outcomes in a large cohort of patients.A consecutive series of 485 RSAs were implanted with the Aequalis Ascend Flex stem. Data collection included preoperative and postoperative clinical and radiographic assessment findings (rotator cuff Goutallier grade; Hamada, Walch, and Favard classifications; range of motion; Constant score) and perioperative data. Patients with a scapular spine fracture following RSA were matched with nonfracture control patients, and preoperative variables were tested to determine whether they were predictive of a scapular spine fracture.A scapular spine fracture following RSA occurred in 21 patients (4.3%), with a mean time to diagnosis of 8.6 months (range, 1-34 months). No preoperative factor was found to be a significant predictor of scapular spine fracture. Both groups showed significant improvements in active mobility measurements and Constant scores from preoperatively to final follow-up (P .001). The control group scored significantly better than the scapular spine fracture group regarding the Constant score and forward flexion.Scapular spine fractures have shown an increased prevalence after onlay-design RSA. This series was not able to link any clear risk factors. Functional results are limited, regardless of the fracture management.

The aim of this work was to evaluate the inter-observer agreement and diagnostic performance values of 7 MRI signs (3 known and 4 new) of long head biceps tendon instability. MRI of 86 patients were retrospectively evaluated. Inter-observer agreement and diagnostic performance of each diagnostic sign and of all combined signs (with the exception of detour sign) were tested for identification of biceps tendon instability, with arthroscopy as the reference standard. Agreement between expert operators was moderate to good. Sensitivity, specificity, and sign accuracy showed a variation respectively of the following: humeral chondral print 72–80%, 62–68%, and 70–76%; subchondral bone edema 24–31%, 84–97%, and 50%; biceps tendon angle 60–71%, 97–100%, and 74–81%, biceps tendon-groove distance 31–47%, 90–100%, and 56–64%; long head biceps subluxation/dislocation on axial plane 49–53%, 97–100%, and 66–70%; displacement sign 74–80%, 74–100%, and 74–87%; detour sign 51–64%, 58–81%, and 62–64%; and all signs 98–100%, 32–61%, and 75–86%. These diagnostic signs, both known and new, individually and/or in combination, provide a valid tool in the MRI diagnosis of long head biceps tendon instability.

Introduction: Subscapularis tendon repair in reverse total shoulder arthroplasty represents a potentially modifiable risk factor for dislocation, and its role continues to be debated. The purpose of the present meta-analysis was to compare the outcomes of the primary lateralized RSAs with and without subscapularis repair in terms of range of motion, clinical outcomes, dislocations, and complications rate. Materials and Methods: A systematic literature search in MEDLINE (Pubmed), Embase, and the Cochrane Central Register of Controlled Trials database was carried up to December 2020. A data extraction form was developed to collect select data from the included studies. The methodological quality was assessed using a Methodological Index for Nonrandomized Studies (MINORS) score. Statistical analysis was performed with Review Manager (Version 5.4, The Cochrane Collaboration). Results: A total of four comparative studies involving 978 patients were included. In the pooled analysis, the reinsertion of the subscapularis yielded better functional outcomes in terms of the constant (P < 0.00001) and ASES (P = 0.002) scores. The forward elevation, external rotation at 0°, internal rotation, and dislocation rates were comparable between the two groups (P = n.s.), while statistically increased abduction was observed in those patients who did not have their subscapularis repaired (P < 0.00001). Conclusion: The results of the present findings suggest that it seems reasonable to reinsert the subscapularis whenever it is present, in good tissue conditions, and with no evidence of fatty degeneration of its muscle belly. Level of evidence: Level III meta-analysis

In the field of external strengthening and repairing of existing reinforced concrete structures, steel reinforced polymers (SRP) systems have emerged as a competitive alternative to the use of the more common carbon and glass fiber reinforced polymer (FRP) composites. Experimental investigations have frequently shown the potentials of these innovative composite systems in improving the performance of deficient structural members. At the same time, additional studies are needed to expand the existing knowledge and either to provide design recommendations or to develop specific guidelines. The paper fills some of the foregoing knowledge gaps by presenting an analytical investigation on the bond behaviour between SRP and concrete in which closed-form solutions are derived to predict the entire debonding propagation process. In particular, accurate and simplified local shear stress-slip (τ-s) laws are employed in the proposed modelling from which different expressions for the interfacial shear stress distribution, the axial stress profile and the concrete-SRP relative displacement (slip) are developed and commented in the paper; analytical estimates of the SRP effective bonded length are provided as well as relationships for calculating the maximum axial stress (or peak force) at SRP laminate debonding. The analytical procedure was, firstly, applied to simulate some single-lap shear tests performed in a previous experimental program with the purpose to investigate the influence on the debonding propagation process of the following main parameters: a) concrete strength, b) concrete surface finish and c) steel tape density. Then, the comparisons between the numerical simulations and the experimental results available for some bond tests have allowed for verifying the accuracy of the proposed modelling.

Background Several modifications to the original Grammont reverse shoulder arthroplasty (RSA) design have been proposed to prevent distinctive issues, such as both glenoid and humeral lateralization. The aim of this systematic review was to determine rates of problems, complications, reoperations, and revisions after onlay lateralized humeral stem RSA, hypothesizing that these are design related. Methods This systematic review was performed in accordance with the PRISMA statement guidelines. A literature search was conducted (1 January 2000 to 14 April 2020) using PubMed, Cochrane Reviews, Scopus, and Google Scholar, employing several combinations of keywords: “reverse shoulder arthroplasty,” “reverse shoulder prosthesis,” “inverse shoulder arthroplasty,” “inverse shoulder prosthesis,” “problems,” “complications,” “results,” “outcomes,” “reoperation,” and “revision.” Results Thirty-one studies with 4893 RSA met inclusion criteria. The 892 postoperative problems and 296 postoperative complications represented overall problem and complication rates of 22.7% and 7.5%, respectively. Forty-one reoperations and 63 revisions resulted, with overall reoperation and revision rates of 1.7% and 2.6%, respectively. Conclusions Problem, complication, and reintervention rates proved acceptable when implanting a high humeral lateralization stem RSA. The most frequent problem was scapular notching (12.6%), and the most common postoperative complication was scapular stress fracture (1.8%). An overall humeral complication rate of 1.9% was identified, whereas no humeral fractures or stem loosening were reported with short stems. Infections (1.3%) were the most common reason for component revision, followed by instability (0.8%). Level of evidence Systematic review IV.

The successful treatment of proximal humeral fractures remains challenging for shoulder surgeons, and failure rates are high, regardless of initial treatment. This study aimed to analyze the clinical and radiographic midterm results of onlay lateralized cementless stem reverse shoulder arthroplasty (RSA) in patients with valgus/varus malunion proximal humerus fracture sequelae without metaphyseal osteotomy. We retrospectively studied 35 cases with the diagnosis of fracture sequelae of the proximal part of the humerus with valgus/varus malunion. The mean duration of follow-up was 4.6 years (range, 2 to 7 years), and the mean time between fracture and arthroplasty was 6 years (1 to 32 years). Seventeen patients (48.6%) had initially been treated nonoperatively. The Constant score (CS), active range of motion, and radiographs of the affected shoulders, as well as the acromion to greater tuberosity (AGT) distance and deltoid length (DL), were analyzed before surgery and at their latest follow-up. A total of thirty-three patients (94.3%) rated their outcome as very good or good. Mean CS, forward flexion, and external rotation improved significantly (p &lt, 0.0001), as did internal rotation and pain (p &lt, 0.05). AGT distance significantly increased postoperatively from 14.7 to 43.3 mm, as did DL from 143 to 170 mm (p &lt, 0.05). There was no correlation between the outcomes and valgus/varus deformity, previous surgeries, or AGT distance/DL. A total of four complications occurred (11.4%): two dislocations were detected (5.7%) and successfully revised with a longer cemented stem. Onlay lateralized uncemented stem RSA improves clinical outcomes and decreases complications when treating valgus/varus malunion fracture sequelae, avoiding intraoperative technical challenges, such as tuberosities osteotomy conscious of bone loss and proper deltoid tensioning.

Background: the choice of treatment of chronic grade III acromioclavicular (AC) joint dislocation is controversial. Several surgical techniques have been described in the literature, responding differently to nonoperative treatment. The aim of this study is to describe a modified technique of stabilizing an AC joint dislocation with the new Infinity-Lock Button System, in order to demonstrate that it is effective in optimizing outcomes and decreasing complications. Methods: this is a retrospective study of 15 patients who underwent surgical stabilization of the AC joint dislocation between 2018 and 2019, through modified surgical technique using the Infinity-Lock Button System. Active range of motion (ROM), Specific Acromio Clavicular Score (SACS) and Constant Score (CS) were evaluated preoperatively and postoperatively at last 18 months follow up. Patients rated their outcomes as very good, good, satisfactory, or unsatisfactory. Results: a total of twelve patients rated their outcome as very good and three as good, no patients were dissatisfied with surgery. The mean Constant Score increased from 38 points preoperatively to 95 postoperatively, the average SACS score decreased from 52 points preoperatively to 10 postoperatively, both significantly. No complications were detected. Conclusion: the described technique is effective for treatment of chronic grade III AC joint dislocation, resulting in elevated satisfaction ratings and predictable outcomes. Nevertheless, further longer term follow-up studies are required.

A novel semi-analytical formulation of the governing equations of an FRP retrofitted reinforced concrete beam under bending, based on the concept of moment-curvature, is presented and it is applied to compute the complete nonlinear load-deflection curve, FRP-concrete interfacial shear stress, the FRP laminate strain and the debonding load of statically determinate RC beams retrofitted by an adhesively bonded FRP laminate. The beam may be subjected to any loading, including uniformly distributed or discrete point load(s). The governing equations satisfy the equilibrium and strain compatibility requirements of the beam but slip at the FRP-concrete interface is permitted. A novel procedure for constructing the full nonlinear moment-curvature relationship of beams undergoing interfacial slip is presented in detail, but it is shown that practically a trilinear relationship is satisfactory for obtaining an accurate estimate of the beam deflection and stresses. The robustness and accuracy of the method are demonstrated by analyzing several beams tested by other researchers under uniformly distributed load or four-point bending, with remarkably close agreement between the experimental and corresponding computed values.

Background There are few investigations comparing lateralized and medialized reverse total shoulder arthroplasty (RTSA) in patients with cuff tear arthropathy. This study assessed the outcomes of 2 RTSA designs. Methods Sixty-eight consecutive cuff tear arthropathy patients (74 shoulders) with a follow-up of at least 24 months received a Grammont or an onlay curved short-stem humeral component, with or without glenoid lateralization; a cementless humeral stem was implanted in >90%. Clinical outcome measures included active range of motion (anterior and lateral elevation, external and internal rotation), pain, and the Constant-Murley score. Radiologic outcomes included radiolucency, condensation lines, cortical thinning, spot weld, loosening and subsidence, and tuberosity resorption for the humeral component and radiolucency, scapular notching, formation of scapular bone spurs, ossifications, and loosening for the glenoid component. Results Both prostheses provided significant differences between preoperative and postoperative scores and showed a similar complication rate. Scapular fractures were found only in the patients who received the curved short-stem implant. Glenoid bone grafting did not significantly affect clinical scores. Both implants provided similar postoperative shoulder mobility, even though the lateralized curved stem was associated with higher delta scores for external rotation (P = .002) and lower rates of scapular notching (P = .0003), glenoid radiolucency (P = .016), and humeral bone remodeling (P = .004 and P = .030 for cortical thinning and spot weld, respectively). Conclusions Medialized and short-stem lateralized RTSA implants provided similar midterm clinical outcomes and range of motion. The curved short stem was associated with higher delta scores for external rotation and a lower rate of radiographic risk factors.

One of the complications in total knee arthroplasty (TKA) is pseudo-patella baja (PPB). PPB is present when there is no shortening of the patellar tendon, but the joint line is elevated. The purpose of this study is to investigate the incidence of PPB after TKA and its clinical effects. A case series of 158 patients undergoing TKA surgery between 1999 and 2012 at the 2nd Department of Orthopaedics and Traumatology, Pisa were retrospectively reviewed. Surgeries were performed by three senior surgeons, using the same surgical procedure for the implantation of a cemented posterior stabilized prosthesis. Lateral radiographs at 30° knee flexion were evaluated and the presence of PPB defined as modified Blackburne–Peel Index (mBPI) of

Steel Reinforced Polymer (SRP) systems have recently emerged as an attractive solution for the external strengthening of reinforced concrete structures. They entail unidirectional fabrics made out of high tensile strength steel cords that can be externally bonded to the substrate via wet lay-up, using either epoxy or polyester resin. Currently, research about the behavior of SRP strengthening systems for concrete structures is evolving but further systematic and comprehensive studies are still needed to ensure the consistency and reliability of the studies performed to date. The present paper contributes to expanding the existing knowledge by presenting the results of an extensive experimental program devoted to investigate the bond behaviour between SRP and concrete substrate. To this purpose, a number of SRP strips were bonded to concrete blocks by a thixotropic organic matrix and the lap joint was subsequently subjected to direct shear tests performed in displacement control. Besides the concrete strength, the following study parameters were considered: (a) the concrete surface roughness in the bonded region, (b) the density of the steel fabric, (c) the ratio of the epoxy covered concrete surface width to the SRP strip width, and (d) the bonded interface length.

Adhesive durability and joint reliability, strictly related to the bonding agents, are key parameters still under evaluation in civil as well as in other engineering fields. Moisture, different environmental agents and temperature (in particular) can strongly affect the performance of the adhesive joints over the time limiting their applicability. The environmental temperature may exceed the glass transition temperature (T g ) of the adhesive formulation entailing relevant changes in its properties, determining, for instance, a transition from a hard to a rubbery behaviour, thus compromising its specific application. Furthermore, due to changes of the temperature values, the structural adhesive can be naturally subjected to a delay or increase in the curing degree. Hence adverse or positive changes in strength and stiffness can be manifested. Within this framework, the topic of the present paper is the study of the hygro-thermal durability of two commercial epoxy resins, suitable for civil engineering applications , respect to the immersion in tap water and sea water for a period of fifteen months at the temperature of 30 °C. To this scope a wide experimental program was developed comprising both End Notch Failure (ENF) tests on the adhesive samples (adherent in glass fiber reinforced polymer , GFRP) for evaluating the pure fracture energy in Mode II of the resins and the water absorption tests for resins and GFRP materials. In general, the results, in terms of fracture energy, show an initial increment (first three-four months) followed by a decrement up to the reaching of a plateau (in the ninth-twelfth month of conditioning). For what concerns the water absorption, the results show that the equilibrium value of both resins is reached in about one month, while that of GFRP samples depend on the type of liquid: three months for tap water and about five months for sea water. Considering the lower activity of the seawater, the longer time to reach the equilibrium value was an expected result.

In most full-composite structures nowadays, pultruded profiles are joined together to form more complex cross-sections that are not produced by the pultrusion process. These unconventional cross-sections represent a critical point in terms of strength and deformability of the whole structure, especially due to the presence of adhesive. This fundamental unknown aspect recently inspired the authors of the present paper to study the mechanical behavior of a glass fiber reinforced polymer (GFRP) profile with a complex cross-section shape obtained by bonding simple pultruded plates (bonded beams) by epoxy resin. The first step was to compare the behaviors of bonded beams with those of similar pultruded ones. With this aim, in a previous paper the flexural global behavior of an I-bonded beam was investigated, highlighting its better performance with respect to the pultruded I-profile in terms of failure load and stiffness. Now the authors would like to extend the study, both experimentally and numerically, to the mechanical behavior of the adhesive web–flange connections in terms of axial stiffness. Seventeen full specimens were tested by performing pull-out tests under force control. A uniformly distributed load was applied to the lower flange in order to favor the detachment of the flange from the web of the profile by using a steel device designed and realized ad hoc . The overall result of the research is that the bonded profile shows a good mechanical behavior justifying its use in technical practice. In addition, the bonded beams represents a valid alternative to the pultruded profile especially when the latter is not available on the market. In more detail, in bonded beams, the presence of the resin (instead of resin and fibers as in pultruded beams) at the web-to-flange connection does not affect the flexural global behavior but does penalize the axial behavior of their connections, as here demonstrated.

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Introduction Recurrent anterior glenohumeral instability has been studied in the young population and limited evidence is available for adolescent patients. Our study is a retrospective review of patients aged Methods Forty-five patients were available for review. Clinical outcomes were assessed by range of movements, stability, Walch-Duplay score (WDS), Rowe score (RS), Constant-Murley score (CMS), Subjective Shoulder Value (SSV), and return to sport. Radiographs were reviewed for osteoarthritis and complications. Results The median age of patients was 15.7 years (13-17), and 56% had hyperlaxity. The median follow-up time was 6.6 years (3-26). The median postoperative movements showed recovered elevation (175°), external rotation (60°), and internal rotation (T9 level). Seventy-five percent of patients returned to the same level of sport, and 98% were satisfied. Clinical outcomes showed WDS, RS, and CMS scores of 85, 95, and 84 points, respectively, and an SSV of 95%. Twenty percent of patients described mild postoperative pain, and 1 had persistent stiffness. Other complications included 24% subjective apprehension, 4% redislocation, 4% wound problems, and 2% infection. Nine percent of cases had postoperative arthritis. The overall reoperation rate was 11%: 1 open washout for infection and 4 arthroscopic screw removal due to persistent pain. We found that hyperlaxity, female sex, and large or deep Hill-Sachs lesions were frequently associated with persistent apprehension at the last follow-up. Conclusions The open Latarjet procedure provides a low rate of recurrent instability with acceptable complication rates in the long term for skeletally immature patients. It is an effective, safe treatment option without any significant glenoid growth disturbance.

Relatively recently a steel fabric/laminate has been proposed for externally strengthening concrete structures, using a polymeric resin. The steel fiber-polymer composite system is termed Steel Reinforced Polymer (SRP). To determine the ultimate load capacity of an SRP retrofitted concrete structure, one must accurately predict the SRP-concrete interface debonding load, which requires a robust local bond-slip model. Many design guidelines recommend mode II interfacial fracture energy limit as the failure criterion for FRP-concrete interface. For SRP strengthened members, a suitable constitutive law and failure criterion have not been established yet. Consequently, in this study the applicability of five existing bond-slip interface models for FRP-concrete interface to SRP-concrete interface is examined. The models’ parameters are calibrated for SRP-concrete interface using an experimental database by the present authors and compared with the values suggested by the original authors for FRP-concrete interface. The database involves results of tests on concrete prisms bonded to SRP strips. The experimental interfacial bond-slip relationship for the former interface is observed to have a more precipitous descent after the peak stress than predicted by the existing models; consequently, a new model is proposed here to capture this phenomenon. All the models are calibrated using a classical technique which minimizes the difference between the measured and computed interfacial shear stress values at different slip levels. The results indicate that all the models predict relatively well the slope of the ascending branch of the shear stress-slip curve, but they give substantially different values for the maximum shear stress attainable and noticeably different descending branch profiles. Among these, overall, the proposed model is in relatively better agreement with the experimental results.

Reverse shoulder arthroplasty (RSA) is gradually being considered a reasonable approach to more severe patterns of glenoid erosion. The adoption of RSA has been supported by both clinical and finite element analysis reports that demonstrate the challenges encountered by surgeons when considering arthroplasty in this setting. The Favard and modified Walch classifications using computed tomography are the most common methods of analyzing these deformities in anticipation of glenoid arthroplasty. Surgical correction of superior glenoid inclination, retroversion, and posterior humeral head subluxation can be achieved through various techniques in both TSA and RSA. High-side eccentric reaming, structural or cancellous bone grafting, and augmented glenoid components (and relative combinations of them) are described, with both advantages and disadvantages of each technique. Understanding the full spectrum of treatment options available can allow for the best decision-making for each individual patient’s deformity, when managing these patterns of glenoid bone loss with RSA.

The results of geometrically nonlinear analyses on 43 built-up Pultruded Fibre-Reinforced Polymer (PFRP) columns with closely spaced chords and intermittent interconnections are presented. A comparison between columns with the end sections entirely loaded and columns loaded at the end battens only is reported, showing no appreciable difference in the P-δ response. The effects due to variations of column length and battens spacing are then investigated. It is found that stocky columns with small battens spacing attain pre-buckling failure at the web-flange junctions of the chords for loads approximately equal to 70% of the crushing load. Slender columns fail by global buckling, whereas intermediate-slenderness columns may experience interaction between local and global buckling. A design method is finally proposed.

Periprosthetic joint infections of the shoulder (PJIS) are the major cause for revision within the first two post-operative years, and are challenging both to diagnose and treat. Success depends on early identification of microorganisms, appropriate surgical procedures and efficient antibiotic administration. The peculiar microbiology of the shoulder may render the criteria for hip/knee PJI management inappropriate. In addition, later cases with clinically subtle signs often present diagnostic challenges. In recent years, specific issues of PJIS have been managed through the use of new instruments, such as MicroDTTect in pathogen detection and Bioactive Glass and tantalum cones in humeral bone loss. In the literature to date, no reports have been found that discuss the application in shoulder revisions and infections. The early identification of the microorganisms that cause infection may help improve both treatment strategies and the efficacy of therapy. MicroDTTect proved to be more efficient than swab collection for bacterial identification in orthopedic surgery, thus reducing analysis costs. The increasing number of shoulder arthroplasties is associated with an increase in the number of revisions. In cases of massive metaphyseal humeral bone loss, several techniques have been described; no reports have been reported regarding tantalum in humeral bone loss management. In some cases the tantalum cones required adaptation for femoral diaphysis in the augmentation of the humerus metaphysis and bone loss management improvement. Obtaining stable osseointegration of prosthetic implants is one of the greatest issues in orthopedic surgery, and even more crucial in revisions. Bioactive glasses demonstrated good regenerative and osseointegration properties, and an excellent candidate as a bone graft, scaffold and antibiotics deliverer. The Bioactive glasses were used to increase prosthesis-bone interface stability and fill bone defects in PJIS revision surgeries, contributing to the prevention of re-infection. Longer-term follow-up will be necessary to determine if construction durability is improved in the long term.

Composite materials for strengthening existing structural members represent a valid alternative to the traditional strengthening techniques. In particular, Fabric Reinforced Cementitious Matrix (FRCM) composites have been successfully employed to strengthen existing reinforced concrete and masonry structures. Among the different FRCM composites available on the market, the attention of the authors was recently focalized on systems composed of high tensile strength steel cords embedded in a cementitious matrix (systems also well known as Steel Reinforced Grout, SRG). The main failure mechanism of FRCM is represented by the debonding at the matrix-fiber interface. Therefore, the study of the bond behavior of FRCM composites is a key topic to develop reliable design procedures. In this paper, the applicability of different existing bond-slip interface models for FRP-concrete interface to SRG system is studied. The different parameters characterizing the models are calibrated by using an experimental database available by the authors and including results of direct single-lap shear tests on concrete prisms bonded to SRG strips. All the models are calibrated using a classical technique which minimizes the difference between the measured and computed interfacial shear stress values at different slip levels. The results indicate that all the models predict relatively well the slope of the ascending branch of the shear stress-slip curve, but they give substantially different descending branch profiles. The calibrated models are, then, compared with some other laws proposed in the literature for PBO and basalt FRCM systems; some of them are also implemented within a numerical procedure developed by the authors for the estimation of both the maximum axial stress at debonding and the corresponding effective bonded length of the SRG strip. The comparison with the experimental data has allowed for verifying the accuracy of the calibrated bond-slip models.

A discussion on some design rules for pultruded fiber-reinforced plastic (PFRP) profiles reported by guideline CNR DT-205/2007 from National Research Council of Italy is presented in the paper. At eight years after approval of this technical document, several changes and improvements are required following recent research findings and supplemental design rules should be incorporated into a future revision. The general framework for the design of columns and beams is outlined. A new closed-form expression for the local buckling moment for beams in major-axis bending is presented.

In this paper, the debonding of adhesive double-lap joints between FRP adherents is analyzed with regard to the influence of an initial adhesion defect on their ultimate capacity. The analysis is carried out by using the interface cohesive models proposed by Hutchinson & Suo, Xu & Needleman, and Camacho & Ortiz. The mechanical model utilized takes into account the shear deformability of the adherents and the coupling effects between axial and shear/flexure behavior. The model is non-linear due to the hypothesis of a cohesive interface adopted for the adhesive layer. The numerical results, obtained via finite element analysis, have highlighted that the model of Hutchinson and Suo is less conservative than the other two and that joints subjected to axial forces are less sensitive to initial adhesion defects than ones loaded by both axial and shear forces.

International audience; This paper presents some experimental results dealing with the mechanical performance of composite beams obtained by bonding Glass Fibre Reinforced Polymer (GFRP) rectangular pultruded panels by means of an epoxy structural adhesive. The flexural response of these bonded beams was compared with those obtained by the pultrusion process with the same geometrical and material properties. As a matter of fact, no significant loss of performance emerged in terms of failure load; moreover, an increase of pre-failure stiffness was observed. This result may allow us to consider bonded GFRP beams as a viable simplification within the field of composite structures.

Steel Reinforced Polymer (SRP) systems have recently emerged as attractive solutions for external strengthening and repairing of existing structures. Experimental studies have frequently shown the potentials of these innovative composite systems in improving the performance of concrete and masonry structures. However, additional studies are needed to expand the existing knowledge and either to provide design recommendations or to develop specific guidelines. The paper fills some of the foregoing knowledge gaps by discussing the experimental results of 130 direct single-lap shear tests performed to investigate the bond behavior between the SRP reinforcement and the concrete substrate; different concrete surface finishes were investigated, i.e., sandblasted, bush hammered and grinded which are among the surface treatments mostly used in practice. Comparisons between the maximum load resisted by the SRP-concrete joints and the theoretical value calculated using some relationships available for similar FRP-concrete assemblages are discussed. Then, the experimental results relative to SRP-concrete joints with sandblasted finish were used to: a) calibrate the parameters of some bond-slip interface models available in the literature for FRP-concrete interface, and b) compare the obtained relationships with the interface models proposed in a previous study for SRP-concrete joints with bush-hammered and grinded concrete surface finish only. The bond-slip models calibrated for the three considered concrete surfaces were finally used to develop theoretical relationships between the maximum bond stress in the steel strip at debonding and the concrete strength. Comparisons with the experimental data were also performed.

International audience; In this paper a methodology to model a GFRP adhesive connections by using an imperfect soft interface model is presented. The model based on Kachanov's theory considered a cracked thin adhesive. Within this framework, the mechanical properties and the initial damage (diffuse initial cracks) of the adhesive layer has been experimentally evaluated. With a modified Arcan system, static tests were performed on adhesively bonded assemblies in tensile and shear solicitation mode considering three different adhesive thicknesses. The experimental results highlighted how the thickness of adhesive influences the mechanical strength and stiffness of the bonded connection. CT-scans were performed to measure the porosity rate in the adhesive layer. Furthermore, the excellent comparison of numerical and experimental data of an adhesive GFRP bonded connections allow us to consider the imperfect soft interface model proposed as highly competitive to evaluate complex structure performance in civil engineering context. A parametric analysis has been proposed to provide a formula able to describe the full response of the structure at varying adhesive property.

This study presents the results of an experimental investigation on the durability of a commercial High Performance Fiber Reinforced Concrete (HPFRC) subjected to rapid freeze/thaw cycles. High-performance fiber reinforced concrete (HPFRC) is currently being used in the construction industry both for strengthening existing members and for controlling opening cracks in new ones. In literature there are many studies focused on the evaluation of the HPFRC mechanical properties varying the matrix composition and/or the type and quantity of the fibers but a lack of knowledge exists for what concerns its durability. Durability of concrete may be defined as the ability of concrete to resist weathering conditions, chemical attack and abrasion while maintaining its desired engineering properties. In particular, durability can be defined by the percentage ratio of the dynamic modulus of elasticity after a number of freeze and thaw cycles to the corresponding value before the freeze and thaw cycles. In this paper, three different concrete mixtures with various fiber volume fraction , i.e. 0%, 1.25% and 2.50%, were examined. Seventy-five freeze-thaw cycles were performed according to UNI 7087-2017 on five prismatic specimens per each concrete mixture while other three specimens were selected as reference samples. In order to evaluate the durability factor of the three mixture, the resonant frequencies (transversal, longitudinal and torsional) and the dynamic moduli of elasticity were measured using the Impact Resonance Method (IRM) provided by the ASTM C215.

A semi-analytical model is developed to determine in FRP retrofitted reinforced concrete (RC) beams the interfacial shear and peeling stresses, the FRP laminate and the RC section strain and stresses at all loading stages up to failure. The FRP is assumed to be externally bonded to the beam but can undergo slip and relative vertical displacement at its interface with the concrete. The model is developed by satisfying the requirements of equilibrium and strain compatibility while concurrently allowing for interfacial deformations. FRP is treated as a linear elastic, steel as elasto-plastic strain hardening and concrete as fully nonlinear material in compression and tension, including tension stiffening. The governing equations are formulated as two second order differential equations with their dependent variables being the strain in the FRP and the relative normal displacement of the interface. The equations are solved for discrete states (uncracked, cracked, yielded) experienced by the RC section and their associated level of interfacial slip. The model results are compared with available experimental results for several beams retrofitted with carbon FRP or steel reinforced polymer (SRP) laminates subjected to either four point bending or simulated uniform load, with satisfactory agreement between them.

Composite materials consisting of high tensile strength steel cords embedded in a cementitious matrix (Steel Reinforced Grout, SRG) are becoming an attractive solution for strengthening existing structures thanks to the lower cost than “traditional” FRP systems, the isotropy of the steel and the ability of the mortar to resist fire. With respect to Steel Reinforced polymer (SRP) systems – whose mechanical behavior is predominantly dependent on the strength of the substrate to which the steel fibers are epoxy bonded – the mechanical properties of SRG systems are mainly dependent on the cement-based matrix which is sensitive to curing the installation conditions and methods. The experimental results presented and discussed in this paper contribute to expanding the existing knowledge on the bond behavior between the SRG and concrete substrate. To this purpose, a number of SRG strips were bonded to concrete blocks by an inorganic matrix and the lap joint was subsequently subjected to direct shear tests performed in displacement control. Since mortars are very sensitive to environmental conditions and humidity as previously mentioned, two different curing conditions were used. In the first case – termed “curing a” – specimens were cured at room temperature for 28 days and wet cloths were placed on top of the composite surface each day for two weeks. In the second case – termed “curing b” – specimens were just cured at room temperature for 28 days. In addition to the curing condition, the following study parameters were considered: (a) the concrete surface roughness in the bonded region, (b) the density of the dry steel fabric, (c) the bonded interface length, and (d) the concrete strength. Relatively to the latter parameter, concrete prisms were broadly divided into two strength groups: Normal Strength Concrete (NSC) having an average concrete cylindrical strength between 13 and 25 MPa and High Strength Concrete (HSC) having an average strength equal to 40 MPa. Experimental evidence underlines that SRG systems mainly exhibited a debonding failure at steel fibers-matrix interface (due to the sliding phenomena) irrespective of the concrete strength and surface finish. Furthermore, like the SRP systems, the low tape density showed better performances with respect to the higher densities considered in this paper, both in terms of the efficiency factor (i.e., the ratio between the tensile stress experienced by SRG in each test and the average tensile ultimate strength of dry steel fabric) and of the maximum force transferred by the system.

International audience

Purpose: The aim of this systematic review is to analyze the effect of tibial rotational alignment after total knee arthroplasty (TKA) on clinical outcomes and assess the eventual cut-off values for tibial TKA rotation leading to poor outcomes. Methods: A detailed and systematic search from 1997 to 2017 of the Pubmed, Medline, Cochrane Reviews, and the Google Scholar databases was performed using the keyword terms “total knee arthroplasty”, “total knee replacement”, “tibial alignment”, “tibial malalignement”, “tibial rotation”, “rotational error”, “axis”, “angle”, “tibial malrotation”, “clinical outcome”, in several combinations. The modified Coleman scoring methodology (mCMS) was used. All the primary TKAs studies analyzing correlation between clinical results and tibial rotation were included. Results: Five articles met the inclusion criteria. A total of 333 arthroplasties were included in this review; 139 had tibial component malalignment, while 194 were in control groups. The mean age of patients was 67.3 (SD 0.57) years. The mean average postoperative follow-up delay was 34.7 months (range 21–70). The mean mCMS score was 59.2 points indicating good methodological quality in the included studies. Functional outcomes were assessed through KSS, OKS, KOOS and VAS, negatively related to tibial internal rotation. Conclusions: Our review confirmed that excessive internal rotation of the tibial TKA component represents a significant risk factor for pain and inferior functional outcomes after TKA (> 10° of internal rotation demonstrated the common value), since external rotation does not affect the results. However, a universal precise cut-off value has not been found in the available literature and there remains a debate about CT rotation assessment and surgical intra-operative landmarks. Level of evidence: III. Purpose: The aim of this systematic review is to analyze the effect of tibial rotational alignment after total knee arthroplasty (TKA) on clinical outcomes and assess the eventual cut-off values for tibial TKA rotation leading to poor outcomes. Methods: A detailed and systematic search from 1997 to 2017 of the Pubmed, Medline, Cochrane Reviews, and the Google Scholar databases was performed using the keyword terms “total knee arthroplasty”, “total knee replacement”, “tibial alignment”, “tibial malalignement”, “tibial rotation”, “rotational error”, “axis”, “angle”, “tibial malrotation”, “clinical outcome”, in several combinations. The modified Coleman scoring methodology (mCMS) was used. All the primary TKAs studies analyzing correlation between clinical results and tibial rotation were included. Results: Five articles met the inclusion criteria. A total of 333 arthroplasties were included in this review; 139 had tibial component malalignment, while 194 were in control groups. The mean age of patients was 67.3 (SD 0.57) years. The mean average postoperative follow-up delay was 34.7 months (range 21–70). The mean mCMS score was 59.2 points indicating good methodological quality in the included studies. Functional outcomes were assessed through KSS, OKS, KOOS and VAS, negatively related to tibial internal rotation. Conclusions: Our review confirmed that excessive internal rotation of the tibial TKA component represents a significant risk factor for pain and inferior functional outcomes after TKA (> 10° of internal rotation demonstrated the common value), since external rotation does not affect the results. However, a universal precise cut-off value has not been found in the available literature and there remains a debate about CT rotation assessment and surgical intra-operative landmarks. Level of evidence: III.

Glass Fiber Reinforced Polymer (GFRP) I-beam-column adhesively bonded connections are tested under combined bending and shear. The special feature of the novel connection is the wrapping of the seat angles at the connection by a carbon fiber reinforced polymer (CFRP) fabric wrap. The wrap is primarily intended to alter the connection failure mode from brittle to pseudo-ductile, thus providing adequate warning of impending failure. Four moment resisting connection configurations are tested, including the reference configuration without the wrap. It is observed that the connection failure is initiated by the fracture of the adhesive, but the provision of the wrap, together with a steel seat angle, alters the failure mode from brittle to pseudo-ductile. The post-peak load deformation is achieved without a large drop in the resistance of the connection. On other hand, the connection with the wrapping and a GFRP seat angle can also change the failure mode to pseudo-ductile, but it could not be done without a large reduction in the connection resistance after the peak load.

Introduction. Intramedullary nail is an important component of modern treatment of pertrochanteric femur fractures. Objective. In elderly population, pertrochanteric fractures treated with unreamed intramedullary nails cause less deep infections when compared to reamed intramedullary nails. Patients and Methods. From April, 2010 to May, 2012 at the Department of Orthopedics and Traumatology, Gaetano Rummo Hospital (Benevento, Italy), 156 patients with pertrochanteric fracture, average age 82.7 years (75-102 years), were treated. In the analyzed case, there were 90 females and 66 males with pertrochanteric fractures. The respondents were divided into two groups. The first group consisted of 78 respondents who were treated with reamed intramedullary nails and the second group of 78 respondents treated with unreamed intramedullary nails. Discussion. Infections are not the most common postoperative complications. The risk of infection is increased in patients with comorbidity and in cases when there is an empty space between the intramedullary nail fixation and bone. Proximal femoral fractures carry a high mortality, but its causes are unclear. Conclusion. Our research has shown that the application of unreamed intramedullary nails in the treatment of pertrochanteric femoral fractures reduces a mortality risk and risk of infection.

International audience; The connections in FRP structures are commonly made using bolted connections, akin to those used in steel structures. In fact, some FRP profiles manufacturers [1] and design guidelines [2] stipulates that bonded connections should not be allowed for primary load bearing components, where failure of the connection could lead to progressive collapse or unacceptable risks. In the latter situations, their use is permitted only in combination with or as a backup for bolted connections. As stated in [1], the main reason for the prohibition of bonded connections is lack of knowledge about and experience with the performance of such connections. Theoretically, there are reasons to believe that bonded connections can surpass bolted connections in FRP composite structures. While bonded lap joints have been extensively investigated in composites, for beam-to-column bonded connections there are no experimental or numerical results available to assess their strength, stiffness and overall performance. To fill this gap in knowledge, recently the authors experimentally investigated the behavior of full-scale bonded beam-to-column moment resisting connections demonstrating that the complete aforementioned prohibition appears to be unjustified. The next step consists to develop a predictive model of such a connection in order to make a comparison with experimental results, in terms of ultimate bending moment, as well as to analyze the role played by several features. Among them, the main ones are the thickness of the adhesive layer (in the experimental program it was constant and equal to 2mm), the friction at the interface (before applying the adhesive the surfaces are treated removing the chopped-glass-mat in order to permit the resin to permeate between the fibers) and the load condition (in the experimental program the connection was subjected to shear and bending moment). Within this framework, an interface model, able to take into account finite strains [4] as well as damage, was developed using asymptotic techniques [5]. In a first study [6], dealing with a classical double lap joints made of GFRP material and an epoxy resin as a glue, under tensile load condition, the model was tested reproducing damage in the adhesive interface as experimentally observed. Relative to the beam-to-column connection, the numerical model furnished useful informations in view of an improvement about its strength and stiffness. References [1] Fiberline Design Manual.