Second Generation of Tissue-Engineered Ligament Substitutes for Torn ACL Replacement: Adaptations for Clinical Applications.

The anterior cruciate ligament (ACL) of the knee joint is one of the strongest ligaments of the body and is often the target of traumatic injuries. Unfortunately, its healing potential is limited, and the surgical options for its replacement are frequently associated with clinical issues. A bioengineered ACL (bACL) was developed using a collagen matrix, seeded with autologous cells and successfully grafted and integrated into goat knee joints. We hypothesize that, in order to reduce the cost and simplify the model, an acellular bACL can be used as a substitute for a torn ACL, and bone plugs can be replaced by endobuttons to fix the bACL in situ. First, acellular bACLs were successfully grafted in the goat model with 18% recovery of ultimate tensile strength 6 months after implantation (94 N/mm2 vs. 520). Second, a bACL with endobuttons was produced and tested in an exvivo bovine knee model. The natural collagen scaffold of the bACL contributes to supporting host cell migration, growth and differentiation in situ post-implantation. Bone plugs were replaced by endobuttons to design a second generation of bACLs that offer more versatility as biocompatible grafts for torn ACL replacement in humans. A robust collagen bACL will allow solving therapeutic issues currently encountered by orthopedic surgeons such as donor-site morbidity, graft failure and post-traumatic osteoarthritis.

Low-value injury care in the adult orthopaedic trauma population: a protocol for a rapid review.

INTRODUCTION: Orthopaedic injuries affect almost 90% of trauma patients. A previous scoping review and expert consultation survey identified 15 potential low-value intra-hospital practices in the adult orthopaedic trauma population. Limiting the frequency of such practices could reduce adverse events, improve clinical outcomes and free up resources. The aim of this study is to synthesise the evidence on intra-hospital practices for orthopaedic injuries, previously identified as potentially of low value. METHODS AND ANALYSIS: We will search Medline, Excerpta Medica Database (EMBASE), the Cochrane Central Register of Controlled Trials and Epistemonikos to identify systematic reviews, randomised controlled trials (RCTs), quasi-RCTs, cohort studies and case-control studies that evaluate selected practices according to a priori PICOS statements (Population-Intervention-Comparator-Outcome-Study design) . We will evaluate the methodological quality for systematic reviews using the Measurement Tool to Assess Systematic Reviews version 2 (AMSTAR-2). Risk of bias in original studies will be evaluated with the Cochrane revised tool for RCTs (RoB2) and with the risk of bias in non-randomised studies of interventions (ROBINS-I) tool. If for a given practice, more than two original studies on our primary outcome are identified, we will conduct meta-analysis using a random effects model and assess heterogeneity using the I2 index. We will assess credibility of evidence (I-IV) based on statistical significance, sample size, heterogeneity and bias as per published criteria. ETHICS AND DISSEMINATION: Ethics approval is not required as original data will not be collected. Knowledge users from three level I trauma centres are involved in the design and conduct of the study in accordance with an integrated knowledge translation approach. Findings related to the rapid review will be available in May 2020. They will be presented to key stakeholders to inform discussions and raise awareness on low-value injury care. In addition, results will be disseminated in a peer-reviewed journal, at national and international scientific meetings and to healthcare associations.

Potential of skin fibroblasts for application to anterior cruciate ligament tissue engineering.

Fibroblasts isolated from skin and from anterior cruciate ligament (ACL) secrete type I and type III collagens in vivo and in vitro. However, it is much easier and practical to obtain a small skin biopsy than an ACL sample to isolate fibroblasts for tissue engineering applications. Various tissue engineering strategies have been proposed for torn ACL replacement. We report here the results of the implantation of bioengineered ACLs (bACLs), reconstructed in vitro using a type I collagen scaffold, anchored with two porous bone plugs to allow bone-ligament-bone surgical engraftment. The bACLs were seeded with autologous living dermal fibroblasts, and grafted for 6 months in goat knee joints. Histological and ultrastructural observations ex vivo demonstrated a highly organized ligamentous structure, rich in type I collagen fibers and cells. Grafts' vascularization and innervation were observed in all bACLs that were entirely reconstructed in vitro. Organized Sharpey's fibers and fibrocartilage, including chondrocytes, were present at the osseous insertion sites of the grafts. They showed remodeling and matrix synthesis postimplantation. Our tissue engineering approach may eventually provide a new solution to replace torn ACL in humans.

New ligament healing model based on tissue-engineered collagen scaffolds.

The anterior cruciate ligament (ACL) is often the target of knee trauma. This ligament does not heal very well, leading to joint instability. Long-term instability of the knee can lead to early arthritis and loss of function. To develop efficient strategies to stimulate posttraumatic ACL regeneration in vivo, a good healing model is needed in vitro. Such a model must remain as simple as possible, but should include key features to provide relevant answers to precise questions about the clinical problem addressed. Here, we report tissue-engineered type I collagen scaffolds developed to establish an ACL healing model in vitro and a potential ACL substitute in vivo. Such scaffolds were used to evaluate ACL cell growth, migration, and the capacity to synthesize and assemble collagen fibers for up to 40 days in vitro and up to 180 days in vivo. They were anchored with two bone plugs to allow their static stretching in culture and to facilitate their surgical implantation in knee joints. Our results have shown that living ACL fibroblasts can attach, migrate, and colonize this type of scaffold. In vitro, the cells populated the scaffolds and expressed mRNAs coding for the prolyl-4-hydroxylase, involved in collagen fibers' assembly. In vivo, acellular implants were vascularized and populated with caprine cells that migrated from the osseous insertions toward the center of the grafts. This model is a very good tool to study ACL repair and identify the factors that could accelerate its healing postsurgery.

Surgical treatment of a displaced lateral malleolus fracture: the antiglide technique versus lateral plate fixation.

OBJECTIVES: To assess the outcomes of the surgical management of "isolated" displaced lateral malleolar fractures, comparing the techniques of lateral plating and antiglide plating as described previously. DESIGN: This is a retrospective review, being largely a surgeon-randomized comparative study. SETTING: The study was carried out at a university teaching hospital that serves as a provincial trauma referral service and provides local community care. The senior surgeons are all orthopaedic trauma subspecialists. PATIENTS: A total of 193 patients meeting our inclusion criteria, with isolated lateral malleolus fractures surgically treated at the Vancouver General Hospital between 1987 and 1998, were studied. INTERVENTION: Eighty-five were treated with antiglide plating, whereas the remaining 108 patients underwent traditional lateral plating. MAIN OUTCOME MEASURES: The functional results were evaluated with the ankle scoring system described previously. We also compared the complication rates, including failure of fixation, infection, wound dehiscence, and need for hardware removal. RESULTS: Both groups were comparable for age, sex distribution, mechanism of injury, and occupation. There was no difference in ankle score, function, and infection rate. The incidence of wound dehiscence and reoperation for hardware removal was slightly higher in the lateral plate group, but the difference was not statistically significant. CONCLUSIONS: The outcome of the surgical management of a displaced lateral malleolus fracture is comparable with both techniques. Although few studies have reported some advantages using the antiglide technique, our data do not support one technique over the other.