Equal results were seen for patellar and hamstring tendon autograft anterior cruciate ligament reconstructions at 2 years after surgery. Both techniques seem to improve patients' performance.

The aim of this study was to describe the contrast-enhanced magnetic resonance imaging (MRI) appearance of bone tunnel enlargement detected on radiography after anterior cruciate ligament (ACL) reconstruction with semitendinosus and gracilis tendon endobutton (STG-endobutton) fixation technique. Fourteen patients with a STG-endobutton ACL reconstruction were examined 3 months (n = 1), 1 year (n = 1) and 2 years (n = 12) postoperatively. An age- and sex-matched group with a bone-patellar tendon-bone (BTB) autograft ACL reconstruction with similar follow-up was taken as control. Data on clinical examination, laxity and isokinetic muscle torque measurements, anteroposterior and lateral view radiography were obtained, and knee scores (Lysholm and Tegner) were collected. Contrast-enhanced MRI was performed in the STG-endobutton group with a 1.5-T imager. There were no statistical differences between the groups with respect to clinical findings, stability tests, or knee scores. In the STG-endobutton group the average femoral and tibial bone tunnel diameter detected on anteroposterior view radiography had increased at 2-year follow-up by 33% and 23%, respectively. On MRI the ligamentous graft itself was not enhanced by the contrast medium whereas periligamentous tissue within and around the STG graft bundles showed mild contrast enhancement. In conclusion, the MRI results suggest that enhancing periligamentous tissue accumulated in and around the STG graft associated with the tunnel expansion. In spite of the significant bone tunnel enlargement observed on the follow-up radiography the STG-endobutton knees were stable and the patients satisfied.

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The MRI appearance of ACL autograft is variable on proton density- and T -weighted images. Periligamentous tissue showing contrast enhancement is a typical MRI finding after clinically successful ACL reconstruction.

Remanufacturing is recognized as a major circular economy option to recover and upgrade functions from post-use products. However, the inefficiencies associated with operations, mainly due to the uncertainty and variability of material flows and product conditions, undermine the growth of remanufacturing. With the objective of supporting the design and management of more proficient and robust remanufacturing processes, this paper proposes a generic and reconfigurable simulation model of remanufacturing systems. The developed model relies upon a modular framework that enables the user to handle multiple process settings and production control policies, among which token-based policies. Customizable to the characteristics of the process under analysis, this model can support logistics performance evaluation of different production control policies, thus enabling the selection of the optimal policy in specific business contexts. The proposed model is applied to a real remanufacturing environment in order to validate and demonstrate its applicability and benefits in the industrial settings.

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Virtual organizations (VOs)

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