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Posterolateral corner knee injuries are clinically significant, and often require surgical reconstruction. The optimal knee brace following posterolateral corner reconstructions has not yet been determined via clinical nor biomechanical study. We sought to evaluate the stiffness of six types of knee braces to determine the ideal brace type for reducing varus forces, which may have clinical utility for posterolateral corner knee reconstruction rehabilitation. Six different groups of knee braces underwent mechanical testing: cruciate braces, cruciate braces with a valgus bend, medial unloaders, articulating sleeves, hinged braces, and tri-panel immobilizers. Each brace was fitted to the same fiberglass leg model and was secured to the testing apparatus. Force was applied under four-point bending to generate a varus moment about the artificial knee. The stiffness in Newtons per millimeter (N/mm) of each brace was calculated from the slope of the force-displacement curve. The cruciate brace with a valgus bend had the highest average stiffness at 192.61 N/mm (SD 28.53). The articulating sleeve was the least stiff with an average stiffness of 49.86 N/mm (SD 8.99). Stiffness of the cruciate brace was not statistically different compared to cruciate valgus ( p  = 0.083) or medial unloader ( p  = 0.098). In this experimental design, a cruciate brace with a valgus bend was shown to have the highest overall stiffness, while an articulating sleeve had the lowest stiffness. Future work will investigate whether this translates into clinical performance.

Background: The all-inside anterior cruciate ligament reconstruction (ACLR) procedure uses a single hamstring tendon folded twice and secured to itself to form a 4-stranded graft. There are several possible configurations for preparing the graft., Purpose: To investigate the biomechanical properties of a new graft preparation technique in comparison with 2 commonly used configurations., Study Design: Controlled laboratory study., Methods: Five porcine flexor tendons were prepared into the test graft configuration: side-to-side fixation with a backup fixation at the button loop (graft M). The test configuration was compared with the results of a previous study that included grafts with simple interrupted sutures (graft A; n = 5) and end-to-end fixation (graft C; n = 5). All grafts were subjected to the same mechanical testing protocol to determine the mean failure load, stiffness, rate of elongation, and total elongation during both cyclic loading and pull to failure. Differences between groups were evaluated., Results: Graft A had a significantly lower failure load (637 ± 99 N) compared with graft M (883 ± 66 N; P = .002) and graft C (846 ± 26 N; P = .002). Graft A also had significantly lower stiffness (166 ± 12 N/mm) compared with graft M (215 ± 8 N/mm; P < .001) and graft C (212 ± 11 N/mm; P < .001). Graft C had a significantly lower elongation during cyclic loading (3.42 ± 0.24 mm) compared with graft M (4.37 ± 0.74 mm; P = .026) and graft A (4.90 ± 0.88 mm; P = .006). The unsecured fixation was the weakest graft, with the lowest failure load and stiffness. The new side-to-side configuration and end-to-end configuration were equally strong., Conclusion: The new side-to-side configuration was not biomechanically superior to the end-to-end configuration; however, they were both stronger than unsecured fixation., Clinical Relevance: As the all-inside ACLR is gaining popularity, this study provides surgeons with a new method of preparing grafts and evaluates the method with respect to currently used configurations., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: Support for this study was received from the Edmonton Civic Employees Charitable Fund. The adjustable button-loop devices used were contributed by Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2021.)

Background: All-inside anterior cruciate ligament reconstruction (ACLR) is an emerging technique used to treat ACL injuries. The all-inside technique uses a 4-stranded graft made from a single tendon that is looped on itself. The 4 strands of the graft must be secured to each other to become a closed-loop structure. Various suture configurations exist to secure the graft to adjustable loop devices, and there is a lack of data to support one technique over another. In addition to the primary sutures used to fasten the graft together, accessory sutures can be tied over the button as secondary fixation., Purpose: To evaluate biomechanical properties of 4-stranded grafts prepared in 5 different configurations., Study Design: Controlled laboratory study., Methods: Porcine flexor tendons (N = 25) were prepared in 5 different configurations (n = 5 tendons per group): simple-interrupted sutures (unsecured fixation), side-to-side fixation with and without secondary fixation, and end-to-end fixation with and without secondary fixation. The grafts were put through the same mechanical testing protocol (cyclic loading, pull to failure) to measure average load at graft failure, average displacement at failure, average stiffness, and average elongation rate. Differences between graft preparation techniques were investigated using 1-way analyses of variance (ANOVAs) with post hoc t tests ( P < .05)., Results: Significant 1-way ANOVAs for each biomechanical property were found. Unsecured fixation was the weakest graft preparation with the lowest stiffness (167 ± 12 N/mm), lowest ultimate failure load (637 ± 99 N), and highest elongation rate (0.0033 ± 0.0007 mm/s). End-to-end fixation without secondary fixation showed the highest ultimate failure load (846 ± 26 N), highest stiffness (212 ± 10 N/mm), and lowest rate of elongation (0.0025 ± 0.0001 mm/s). End-to-end fixation, both with and without secondary fixation, as well as side-to-side fixation with secondary fixation showed significantly higher ultimate failure loads than grafts with unsecured fixation. End-to-end fixation performed better than side-to-side fixation; however, for most variables, the difference was not statistically significant. Secondary fixation did not provide significant improvement., Conclusion: The all-inside ACL graft with simple-interrupted sutures is biomechanically inferior to a graft that has its free ends secured to the adjustable tibial loop. Adding secondary fixation to the tibial button does not significantly change the biomechanical properties. Further clinical studies are required to determine whether these findings translate into differences in clinical outcome., Clinical Relevance: All-inside ACLR is gaining popularity in hamstring ACL reconstructive techniques. These results provide surgeons with guidance on the best graft preparation method when using a single quadrupled hamstring tendon graft., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: Funding for this study was received from the Edmonton Civic Employees Charitable Fund. The adjustable-loop buttons used in this study were donated by Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto., (© The Author(s) 2020.)

Background: A pathologically complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) is seen in 30% of the patients with oesophageal cancer. The aim is to identify patient and tumour characteristics associated with a pCR and to develop a nomogram for the prediction of pCR., Patients and Methods: Patients who underwent nCRT followed by surgery were identified and response to nCRT was assessed according to a modified Mandard classification in the resection specimen. A model was developed with age, gender, histology and location of the tumour, differentiation grade, alcohol use, smoking, percentage weight loss, Charlson Comorbidity Index (CCI), cT-stage and cN-stage as potential predictors for pCR. Probability of pCR was studied via logistic regression. Performance of the prediction nomogram was quantified using the concordance statistic (c-statistic) and corrected for optimism., Results: A total of 381 patients were included. After surgery, 27.6% of the tumours showed a pCR. Female sex, squamous cell histology, poor differentiation grade, and low cT-stage were predictive for a pCR with a c-statistic of 0.64 (corrected for optimism)., Conclusion: A nomogram for the prediction of pathologically complete response after neoadjuvant chemoradiotherapy was developed, with a reasonable predictive power. This nomogram needs external validation before it can be used for individualised clinical decision-making., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)