Long-term local effects of carbon fibre in the knee

Editorial Commentary: The Suture-Augmented Anterior Cruciate Ligament Reconstruction Requires Independent Tensioning to Achieve Load Sharing

Countless variations of anterior cruciate ligament repair or reconstruction plus augmentation have existed for decades, but augmentation was associated with complications such as reactive synovitis, instability, loosening, and rupture. Recently, augmentation with ultra-high molecular weight polyethylene suture or suture tape, however, has not been shown to be associated with these complications. The goal when performing suture augmentation is to provide independent tensioning of the suture augment and graft to allow the suture or suture tape to function as a load-sharing device, allowing the graft to see more strain during earlier levels of graft strain until graft elongation occurs to a critical level, whereby the augment will experience more strain and protect the graft. Although long-term outcome studies are pending, animal and human clinical studies do show that ultra-high molecular weight polyethylene, when used as a suture augment for anterior cruciate ligament surgery, is unlikely to cause a significant intra-articular reaction while also providing biomechanical advantages that could prevent early graft rupture during the revascularization phase of healing.

Influence of Heat Treatment of Electrospun Carbon Nanofibers on Biological Response

The main aim of this study is to investigate the effect of fragmentation of electrospun carbon nanofibers (eCNFs) obtained at different temperatures, i.e., at 750 °C, 1000 °C, 1500 °C, 1750 °C and 2000 °C on the cellular response in vitro. In order to assess the influence of nanofibers on biological response, it was necessary to conduct physicochemical, microstructural and structural studies such as SEM, XPS, Raman spectroscopy, HRTEM and surface wettability of the obtained materials. During the in vitro study, all samples made contact with the human chondrocyte CHON-001 cell lines. The key study was to assess the genotoxicity of eCNFs using the comet test after 1 h or 24 h. Special attention was paid to the degree of crystallinity of the nanofibers, the dimensions of the degradation products and the presence of functional groups on their surface. A detailed analysis showed that the key determinant of the genotoxic effect is the surface chemistry. The presence of nitrogen-containing groups as a product of the decomposition of nitrile groups has an influence on the biological response, leading to mutations in the DNA. This effect was observed only for samples carbonized at lower temperatures, i.e., 750 °C and 1000 °C. These results are important with respect to selecting the temperature of thermal treatment of eCNFs dedicated for medical and environmental functions due to the minimization of the genotoxic effect of these materials.

Hydrogel, Electrospun and Composite Materials for Bone/Cartilage and Neural Tissue Engineering

Injuries of the bone/cartilage and central nervous system are still a serious socio-economic problem. They are an effect of diversified, difficult-to-access tissue structures as well as complex regeneration mechanisms. Currently, commercially available materials partially solve this problem, but they do not fulfill all of the bone/cartilage and neural tissue engineering requirements such as mechanical properties, biochemical cues or adequate biodegradation. There are still many things to do to provide complete restoration of injured tissues. Recent reports in bone/cartilage and neural tissue engineering give high hopes in designing scaffolds for complete tissue regeneration. This review thoroughly discusses the advantages and disadvantages of currently available commercial scaffolds and sheds new light on the designing of novel polymeric scaffolds composed of hydrogels, electrospun nanofibers, or hydrogels loaded with nano-additives.

Fibrous Systems as Potential Solutions for Tendon and Ligament Repair, Healing, and Regeneration

Tendon and ligament injuries caused by trauma and degenerative diseases are frequent and affect diverse groups of the population. Such injuries reduce musculoskeletal performance, limit joint mobility, and lower people's comfort. Currently, various treatment strategies and surgical procedures are used to heal, repair, and restore the native tissue function. However, these strategies are inadequate and, in some cases, fail to re-establish the lost functionality. Tissue engineering and regenerative medicine approaches aim to overcome these disadvantages by stimulating the regeneration and formation of neotissues. Design and fabrication of artificial scaffolds with tailored mechanical properties are crucial for restoring the mechanical function of tendons. In this review, the tendon and ligament structure, their physiology, and performance are presented. On the other hand, the requirements are focused for the development of an effective reconstruction device. The most common fiber-based scaffolding systems are also described for tendon and ligament tissue regeneration like strand fibers, woven, knitted, braided, and braid-twisted fibrous structures, as well as electrospun and wet-spun constructs, discussing critically the advantages and limitations of their utilization. Finally, the potential of multilayered systems as the most effective candidates for tendon and ligaments tissue engineering is pointed out.

Scaffolds in the management of massive rotator cuff tears: current concepts and literature review

Injuries to the rotator cuff (RC) are common and could alter shoulder kinematics leading to arthritis. Synthetic and biological scaffolds are increasingly being used to bridge gaps, augment RC repair and enhance healing potential. Our review evaluates the clinical applications, safety and outcome following the use of scaffolds in massive RC repair.

A search was performed using EBSCO-Hosted Medline, CINAHL, Cochrane and PubMed using various combinations of the keywords ‘rotator cuff’, ‘scaffold’, ‘biological scaffold’, ‘massive rotator cuff tear’ ‘superior capsular reconstruction’ and ‘synthetic scaffold’ between 1966 and April 2018. The studies that were most relevant to the research question were selected. All articles relevant to the subject were retrieved, and their bibliographies hand searched.

Synthetic, biosynthetic and biological scaffolds are increasingly being used for the repair/reconstruction of the rotator cuff. Allografts and synthetic grafts have revealed more promising biomechanical and early clinical results than xenografts. The retear rates and local inflammatory reactions were alarmingly high in earlier xenografts. However, this trend has reduced considerably with newer versions. Synthetic patches have shown lower retear rates and better functional outcome than xenografts and control groups.

The use of scaffolds in the treatment of rotator cuff tear continues to progress. Analysis of the current literature supports the use of allografts and synthetic grafts in the repair of massive cuff tears in reducing the retear rate and to provide good functional outcome. Though earlier xenografts have been fraught with complications, results from newer ones are promising. Prospective randomized controlled trials from independent centres are needed before widespread use can be recommended.

Cite this article: EFORT Open Rev 2019;4:557-566. DOI: 10.1302/2058-5241.4.180040

Use of Estradiol Promotes Graft-Bone Healing in Rabbit Model of Anterior Cruciate Ligament Reconstruction With a Polyethylene Terephthalate Ligament

The purpose of this study was to investigate whether the local use of estradiol after anterior cruciate ligament (ACL) reconstruction with a polyethylene terephthalate (PET) artificial ligament graft could promote graft-bone healing. A total of 45 New Zealand white rabbits underwent ACL reconstruction with a PET ligament graft. The experimental groups were administered a local estradiol injection at either a low dose after surgery or a high dose after surgery, and the control group did not receive an injection. Computed tomography (CT) scans and blood sample collection were routinely performed in all three groups. Over time, the serum estradiol levels increased in both experimental groups, and the CT images revealed a trend of a shrinking bone tunnel area in all three groups. The rabbits were randomly sacrificed at 2, 4, and 8 weeks after surgery. The load to failure and stiffness of the experimental groups were significantly higher than those of the control group at 4 and 8 weeks. The histological study identified more bone mineralization in the experimental groups at 4 weeks after surgery compared to the control group. This study showed that the use of estradiol is a promising approach in promoting graft-bone healing in rabbits undergoing ACL reconstruction with a PET ligament graft.

Status and headway of the clinical application of artificial ligaments

The authors first reviewed the history of clinical application of artificial ligaments. Then, the status of clinical application of artificial ligaments was detailed. Some artificial ligaments possessed comparable efficacy to, and fewer postoperative complications than, allografts and autografts in ligament reconstruction, especially for the anterior cruciate ligament. At the end, the authors focused on the development of two types of artificial ligaments: polyethylene glycol terephthalate artificial ligaments and tissue-engineered ligaments. In conclusion, owing to the advancements in surgical techniques, materials processing, and weaving methods, clinical application of some artificial ligaments so far has demonstrated good outcomes and will become a trend in the future.

Scaffolds for tendon and ligament repair and regeneration

Enhanced tendon and ligament repair would have a major impact on orthopedic surgery outcomes, resulting in reduced repair failures and repeat surgeries, more rapid return to function, and reduced health care costs. Scaffolds have been used for mechanical and biologic reinforcement of repair and regeneration with mixed results. This review summarizes efforts made using biologic and synthetic scaffolds using rotator cuff and ACL as examples of clinical applications, discusses recent advances that have shown promising clinical outcomes, and provides insight into future therapy.

Articular cartilage repair: procedures versus products

This review discusses the current perspectives and practices regarding the treatment of articular cartilage injury. Specifically, the authors have delineated and examined articular cartilage repair techniques as either surgical procedures or manufactured products. Although both methodologies are used to treat articular cartilage injury, there are obvious advantages and disadvantages to the application of both, with the literature providing few recommendations on the most suitable regimen for the patient and surgeon. In recent times, cell-based tissue engineering products, predominantly autologous chondrocyte implantation, have been the subject of much research and have become clinically popular. Herein, we review the most used procedures and products in cartilage repair, compare and contrast their outcomes, and evaluate the issues that must be overcome in order to improve patient efficacy in the future.

The use of catalytic carbon deposits as 3D carriers for human bone marrow stromal cells

We studied the possibility of using 3D structures based on carbon catalytic deposits as carriers for human bone marrow stromal cells. It was found that carbon catalytic deposits obtained by gas deposition method using FeCl(3) × 6H(2)O as the catalyst are a biocompatible material for human bone marrow stromal cells promoting adhesion, proliferation, and distribution of cells within the 3D carrier, and therefore can be used for tissue engineering.

In vitro and in vivo studies on biocompatibility of carbon fibres

In the present study we focused on the in vitro and in vivo evaluation of two types of carbon fibres (CFs): hydroxyapatite modified carbon fibres and porous carbon fibres. Porous CFs used as scaffold for tissues regeneration could simultaneously serve as a support for drug delivery or biologically active agents which would stimulate the tissue growth; while addition of nanohydroxyapatite to CFs precursor can modify their biological properties (such as bioactivity) without subsequent surface modifications, making the process cost and time effective. Presented results indicated that fibre modification with HAp promoted formation of apatite on the fibre surface during incubation in simulated body fluid. The materials biocompatibility was determined by culturing human osteoblast-like cells of the line MG 63 in contact with both types of CFs. Both tested materials gave good support to adhesion and growth of bone-derived cells. Materials were implanted into the skeletal rat muscle and a comparative analysis of tissue reaction to the presence of the two types of CFs was done. Activities of marker metabolic enzymes: cytochrome c oxidase (CCO) and acid phosphatase were examined to estimate the effect of implants on the metabolic state of surrounding tissues. Presented results evidence the biocompatibility of porous CFs and activity that stimulates the growth of connective tissues. In case of CFs modified with hydroxyapatite the time of inflammatory reaction was shorter than in case of traditional CFs.

Osteoarthritis in patients with anterior cruciate ligament rupture: a review of risk factors

The risk factors for the development of osteoarthritis (OA) in patients who have had an anterior cruciate ligament (ACL) rupture are reviewed. Although the principle arthrogenic factor is the increased anterior tibial displacement that is associated with the rupture, other direct and indirect factors contribute. Meniscal and chondral injuries can be present before, during, and develop after the index injury, making assessment of the relative importance of each difficult. Most studies concentrate on the radiological changes following ACL rupture and reconstruction. However the rate of significant symptomatic OA needing major surgical intervention is lower. This needs to be considered when advising patients on the management of their ruptured ACL. The long-term outcome in patients who are symptomatically stable following an ACL rupture is uncertain, although in a small cohort of elite athletes all had degenerative changes by 35 years and eight out of 19 (42%) had undergone total knee replacement. At 20 years follow-up the reported risk of developing osteoarthritis is lower after ACL reconstruction (14%-26% with a normal medial meniscus, 37% with meniscectomy) to untreated ruptures (60%-100%).