Flexural performance of reinforced concrete beams strengthened with prestressed near-surface-mounted FRP reinforcements

YesA numerical method for estimating the curvature, deflection and moment capacity of reinforced concrete beams strengthened with prestressed near-surface-mounted (NSM) FRP bars/strips is presented. A sectional analysis is carried out to predict the moment–curvature relationship from which beam deflections and moment capacity are then calculated. Based on the amount of FRP bars, different failure modes were identified, namely tensile rupture of prestressed FRP bars and concrete crushing before or after yielding of steel reinforcement. Comparisons between experimental results available in the literature and predicted curvature, moment capacity and deflection of reinforced concrete beams with prestressed NSM FRP reinforcements show good agreement. A parametric study concluded that higher prestressing levels improved the cracking and yielding loads, but decreased the beam ductility compared with beams strengthened with nonprestressed NSM FRP bars/strips

Usability of the AAOS Appropriate Use Criteria (AUC) for the surgical management of knee osteoarthritis in clinical practice

Purpose The Appropriate Use Criteria (AUC) for the surgical treatment of knee osteoarthritis were developed by the American Academy of Orthopedic Surgeons (AAOS) to guide surgeons in selecting the most evidence-based surgical option. This study aimed to assess the usability of the AUC by comparing the actual surgical treatment provided at our institution with that recommended by the AUC. Methods A retrospective review of the medical charts and radiographs of all patients who underwent surgery for knee osteoarthritis (OA) at our hospital was performed between January and December 2017. Data including each patient’s age, gender, pain level, mechanical symptoms, range of motion (ROM) and instability, radiographic pattern and severity, limb alignment, and type of surgical interventions received were collected. The collected data were input into the AUC application to determine the rate of appropriateness of the treatments. Afterwards, the agreement between the actual treatment provided and the AUC recommendation was assessed. Results A consecutive series of 100 patients were included. The mean age was 63.1 years, with the majority of the patients aged (73%) between 50 and 69 years. Most of the patients were females (74%), and 61% had left knee OA. The most frequent type of patient was a middle-aged patient with function-limiting pain at short distances, no mechanical symptoms or functional instability with full ROM, severe knee multicompartmental radiographic features, and varus or valgus malalignment. Out of the 100 patients, total knee arthroplasty (TKA) was performed in 85 patients, unicompartmental knee arthroplasty (UKA) was performed in 11 patients, and high tibial osteotomy (HTO) was performed in four patients. According to the AUC, 90 (90%) cases were treated with an appropriate surgical treatment, whereas 10 (10%) cases were treated with a maybe appropriate treatment. The actual surgical treatment performed at our hospital was in agreement with the AUC recommendation in 100% of the TKA cases, 90.9% of the UKA cases, and 100% of the HTO cases. Thus, the agreement rate with the AUC was 99% in all surgical cases. Conclusion This study demonstrated that the AUC for the surgical treatment of knee OA can be applied easily in a clinical setting. Most of the treatments provided at our institution were appropriate and in agreement with the AUC recommendations. Additionally, the AUC had a web-based application that was easy to use and simple for identifying treatment recommendations. Level of evidence Retrospective study, level IV.Other Information Published in: Knee Surgery, Sports Traumatology, Arthroscopy License: https://creativecommons.org/licenses/by/4.0See article on publisher's website: http://dx.doi.org/10.1007/s00167-020-05908-7</p