Histological analysis of ACL reconstruction failures due to synthetic-ACL (LARS) ruptures

INTRODUCTION: Anterior Cruciate Ligament (ACL) reconstruction is an established surgical procedure. Synthetic ligaments represent an option for ACL reconstruction. Their popularity declined for the raising concerns due to re-ruptures, knee synovitis and early arthritis related to I and II generation artificial ligaments. The introduction of a III generation synthetic ligament (Ligament Advanced Reinforcement System-LARS) permitted renewed interest in the adoption of this kind of graft. Main purpose of our study was to describe the histological findings on samples obtained from a consecutive series of ACL revision surgeries due to LARS ACL reconstruction failures. Secondary aim was to determine the reason for LARS rupture. METHODS: In a period between 2016 and 2018 eleven patients underwent ACL revision surgery due to LARS ACL reconstruction failure. At the time of the arthroscopic procedure, samples of synovial membrane and remnants of the torn LARS were sent to the Pathological-Anatomy Institute of our Hospital for a histological analysis. RESULTS: Histological analysis of the synovial tissues confirmed the arthroscopic evidence of synovitis mainly characterized by chronic inflammation with predominance of multinucleated giant cells. The adoption of polarized light microscopy revealed the presence of brightly bi-refractive material (LARS wear particles) in the synovial tissue; at higher magnification wear debris were detected inside the cytoplasma of multi nucleated cells. The histological analysis of the removed LARS revealed a surrounding typical foreign body reaction with poor signs of fibrovascular ingrowth of the synthetic ligament. CONCLUSIONS: Our findings could not clearly advocate a unique mechanism of LARS-ACL reconstruction failure: biologic issues (poor tissue ingrowth) and mechanical issues (fibers properties and tunnel position) probably concur in a multi factorial manner. ACL reconstruction using artificial ligaments can not be considered a simple surgery. Artificial augments require some expertise and could therefore achieve better results if used by skilled sport surgeons other than trainees or low volume surgeons. The Authors believe that ACL reconstruction with synthetic devices still have restricted indications for selected patients (e.g. elderly patients who require a fast recovery, professional athlete, autologous tendons not available and/or refusing donor tendons). Our study arises additional suspicion on the unresponsiveness of synthetic fibers and claim some concern in the implantation of synthetic devices

Estimation of Sediment Management Flushing Efficiency in the Valgrosina Reservoir

Sediment trapping by reservoir is a problem of global severity with associated environmental, social and economic repercussions. Reservoirs trap 100% of river bedload and a not negligible percentage of suspended load. The water storage is destinated for decreasing over the time, the aquatic habitat in the downstream channel is increasingly deprived of sediments and, in worst case scenarios, safety levels against dam stability and flood control may be weakened. Planning and operation of sustainable sediment management measures, as flushing, is essential to maintain reservoirs as renewable resources. This work analyses the real case of the Valgrosina reservoir, in the Northern Italy. Here, the managing Company A2A operated some flushing cycles in the recent past. The flushing parameters were evaluated through the REServoir CONservation (RESCON 2) tool. The consultation of site monitoring data aided in calibrating the model. Preliminary results showed that operational flushing efficiency criteria provided in the literature are not fulfilled due to geometrical constraints

Are vascular grafts at risk of occlusion after total hip replacement? A systematic review of the literature

Vascular complications during and after total hip replacement are relatively uncommon despite the close relationship between the involved structures. Previous surgical procedure of arterial reconstruction or substitution may be at higher risk of damage due to the modification in the anatomical landmarks or to the mechanical properties of the grafts different from native vessels. In literature few cases of graft occlusion or failure are reported during or soon after a total hip replacement. The aim of this review is to report them highlighting common features and risk factors. (www.actabiomedica.it)