A triple-strand anatomic medial collateral ligament reconstruction restores knee stability more completely than a double-strand reconstruction: a biomechanical study in vitro.

BACKGROUND: There are many descriptions of medial collateral ligament (MCL) reconstruction, but they may not reproduce the anatomic structures and there is little evidence of their biomechanical performance. PURPOSE: To investigate the ability of "anatomic" MCL reconstruction to restore native stability after grade III MCL plus posteromedial capsule/posterior oblique ligament injuries in vitro. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve cadaveric knees were mounted in a kinematic testing rig to impose tibial displacing loads while the knee was flexed-extended: 88-N anteroposterior translation, 5-N·m internal-external rotation, 8-N·m valgus-varus, and combined anterior translation plus external rotation (anteromedial rotatory instability). Joint motion was measured via optical trackers with the knee intact; after superficial MCL (sMCL), deep MCL (dMCL), and posterior oblique ligament transection; and then after MCL double- and triple-strand reconstructions. Double strands reproduced the sMCL and posterior oblique ligament and triple-strands the sMCL, dMCL, and posterior oblique ligament. The sMCL was placed 5 mm posterior to the epicondyle in the double-strand technique and at the epicondyle in the triple-strand technique. Kinematic changes were examined by repeated measures 2-way analysis of variance with posttesting. RESULTS: Transection of the sMCL, dMCL, and posterior oblique ligament increased valgus rotation (5° mean) and external rotation (9° mean). The double-strand reconstruction controlled valgus in extension but allowed 5° excess valgus in flexion and did not restore external rotation (7° excess). The triple-strand reconstruction restored both external rotation and valgus throughout flexion. CONCLUSION: In a cadaveric model, a triple-strand reconstruction including a dMCL graft restored native external rotation, while a double-strand reconstruction without a dMCL graft did not. A reconstruction with the sMCL graft placed isometrically on the medial epicondyle restored valgus rotation across the arc of knee flexion, whereas a reconstruction with a more posteriorly placed sMCL graft slackened with knee flexion. CLINICAL RELEVANCE: An MCL injury may rupture the anteromedial capsule and dMCL, causing anteromedial rotatory instability. Persistent MCL instability increases the likelihood of ACL graft failure after combined injury. A reconstruction with an anteromedial dMCL graft restored native external rotation, which may help to unload/protect an ACL graft. It is important to locate the sMCL graft isometrically at the femoral epicondyle to restore valgus across flexion

Knee surgery complications related to biomaterials

Recent years have seen a growing interest in biomaterials and use of these materials in the clinical setting is increasing. Despite their advantages, they have also been cited as the source of specific complications and/or fail- ures. Problems such as screw breakage, tunnel enlargement, allergic or foreign body reactions, cyst and abscess formation, or even delayed migration of supposedly biodegradable screws/implants have been reported. This chapter aims to review the basic science and clinical experience with biomaterials currently employed in fixation devices for knee surgery. Information on the clinical implications of biodegradable screws is still limited. Surgeons tend to focus more on the emerging successes of innovations than on the complications and failures (publication bias) of older devices, making it difficult to reliably assess the incidence of such events. More- over, the complexity of possible reactions occurring in the human body cannot be reproduced under controlled laboratory conditions.Neverthe- less, surgeons and patients must be aware of both the advantages and the complications of these devices. Only in this way can informed choices be made, so that both parties are prepared to face and overcome the unde- sired complications, and the improvement of future implants can become a reality

Prevalence of articular cartilage lesions and surgical clinical outcomes in football (soccer) players' knees: a systematic review

"Article in Press" ; "Published Online: April 16, 2016"Purpose: To systematize the available scientific literature on the prevalence of articular cartilage and/or osteo- chondral lesions in football (soccer) playersâ knees, and overview the surgical procedures and functional outcomes and return to sports. Methods: A comprehensive search using Pubmed, Cochrane Library, SPORTDiscus, and CINAHL databases was carried out until September 30, 2015. All English language studies that assessed the outcomes of a surgical technique for the treatment of articular cartilage lesions in football playersâ knees, with a minimum follow-up of 12 months, were included. The reference list of the most relevant papers was screened. The main outcomes of interest were the clinical, arthroscopy or imaging primary outcomes and the return to sports rate. The methodological and reporting qualities were assessed according to Coleman methodology score. Results: The search provided 485 titles and abstracts. Five studies were eligible for inclusion (mean Coleman score of 37.2 points), comprising a total of 183 football players with a mean age of 25.7 years. A total of 217 articular cartilage and/or osteochondral lesions were reported, where the medial and lateral femoral condyles were the most common sites of lesion. The surgical procedures investigated were mosaicplasty, microfracture, autologous chondrocyte implantation, and chondral debridement. Conclusions: No definitive conclusion could be made in respect to the best current surgical technique for articular cartilage and osteochondral lesions. Microfracture and mosaicplasty can provide a faster return to competition and faster clinical and functional results, whereas autologous chondrocyte implantation and/or matrix-induced autologous chondrocytes implantation procedures can enhance longstanding clinical and functional results. Level of Evidence: Level IV, systematic review of Level III and IV studies

MRI laxity assessment

Knee laxity, by definition, is a dynamic and multifactorial condition. MRI evaluation, due to its known capacity in achieving high soft tissue contrast (e.g., meniscus, synovia, ligaments, cartilage) and multiplanar joint assessment without ionizing radiation, has contributed to its popularity in the last decades. However, “traditional�? MRI studies provide static evaluation, thus requiring careful correlation to clinical findings, particularly when dealing with functional ligament stability. This work aims to describe the most important features of current MRI studies when dealing with anterior cruciate ligaments injuries, while also presenting the evolving possibilities of dynamic and objective MRI assessment of knee instability.(undefined

Animal model for chronic massive rotator cuff tear: behavioural and histologic analysis

Purpose Massive rotator cuff tears (MRCT) are usually chronic lesions that present associated degenerative changes of the myotendinous unit that have been implicated in limitations for surgical repair. In order to develop effective therapies, it is important to establish animal models that mimic the hallmarks of the injury itself. Therefore, in the present work, we aimed to (1) optimize a rodent animal model of MRCT that closely reproduces the fatty infiltration of the cuff muscles seen in humans and (2) describe the effects of unilateral or bilateral lesion in terms of histology and behaviour. Methods Massive tear was defined as two rotator cuff tendons—supraspinatus and infraspinatus—section. Twenty-one Wistar rats were randomly assigned to four groups: bilateral lesion (five animals), right-sided unilateral lesion (five animals), left-sided unilateral lesion (five animals) and control (six animals). Behaviour was analyzed with open field and staircase test, 16 weeks after lesion. After that, animals were killed, and the supraspinatus and infraspinatus muscles were processed. Results Histologic analysis revealed adipocytes, fatty infiltration and atrophy in the injured side with a greater consistency of these degenerative changes in the bilateral lesion group. Behaviour analysis revealed a significant functional impairment of the fine motor control of the forepaw analyzed in staircase test where the number of eaten pellets was significantly higher in sham animals (sham = 7 ± 5.0; left unilateral = 2.6 ± 3.0; right unilateral = 0 ± 0; and bilateral = 0 ± 0, p left unilateral = 2 ± 2.1 > right unilateral = 0.8 ± 1.3 > bilateral = 0.8 ± 1.1). Conclusions The present study has been able to establish an animal model that disclosed the hallmarks of MRCT. This can now be used as a valuable, cost-effective, pre-clinical instrument to assist in the development of advanced tissue engineered strategies. Moreover, this animal model overcomes some of the limitations of those that have been reported so far and thus represents a more reliable source for the assessment of future therapeutic strategies with potential clinical relevance.Portuguese Foundation for Science and Technology (FCT)Programa Operacional Regional do Norte (ON.2—O Novo Norte), ao abrigo do Quadro de Referência Estratégico Nacional (QREN), através do Fundo Europeu de Desenvolvimento Regional (FEDER

Arthroscopic repair of ankle instability with all-soft knotless anchors

In recent years, arthroscopic and arthroscopically assisted techniques have been increasingly used to reconstruct the lateral ligaments of the ankle. Besides permitting the treatment of several comorbidities, arthroscopic techniques are envisioned to lower the amount of surgical aggression and to improve the assessment of anatomic structures. We describe our surgical technique for arthroscopic, two-portal ankle ligament repair using an all-soft knotless anchor, which is made exclusively of suture material. This technique avoids the need for classic knot-tying methods. Thus it diminishes the chance of knot migration caused by pendulum movements. Moreover, it avoids some complications that have been related to the use of metallic anchors and some currently available biomaterials. It also prevents prominent knots, which have been described as a possible cause of secondary complaints.info:eu-repo/semantics/publishedVersio

Strength training to prevent falls in older adults: A systematic review with meta-analysis of randomized controlled trials

We performed a systematic review with meta-analysis of randomized controlled trials (RCTs) to assess the effects of strength training (ST), as compared to alternative multimodal or unimodal exercise programs, on the number of falls in older adults (=60 years). Ten databases were consulted (CINAHL, Cochrane Library, EBSCO, EMBASE, PEDro, PubMed, Scielo, Scopus, SPORTDiscus and Web of Science), without limitations on language or publication date. Eligibility criteria were as follows: RCTs with humans =60 years of age of any gender with one group performing supervised ST and a group performing another type of exercise training, reporting data pertaining falls. Certainty of evidence was assessed with Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Meta-analysis used a random effects model to calculate the risk ratio (RR) for number of falls. Five RCTs with six trials were included (n = 543, 76% women). There was no difference between ST and alternative exercise interventions for falls (RR = 1.00, 95% CI 0.77–1.30, p = 0.99). The certainty of evidence was very low. No dose–response relationship could be established. In sum, ST showed comparable RR based on number of falls in older adults when compared to other multimodal or unimodal exercise modalities, but evidence is scarce and heteroge-neous, and additional research is required for more robust conclusions. Registration: PROSPERO CRD42020222908

Mechanical performance and biocompatibility study of methacrylated Gellan gum hydrogels with potential for nucleus pulposus regeneration

Methacrylated gellan gum hydrogels, obtained either by ionic- (iGGMA) and photo-crosslinking (phGG-MA), have been investigated as potential biomaterials for supporting nucleus pulposus (NP) regeneration and/or repair [1,2]. In previous work, some advantages were attributed to GG-MA hydrogels, such as: (i) the possibility to control endothelial cells infiltration and blood vessel ingrowth’s, (ii) tunable and improved mechanical properties, and (iii) in situ gelation, within seconds to few minutes. In this study, the mechanical and biological performance of these hydrogels was firstly evaluated in vitro. Human intervertebral disc (hIVD) cells obtained from herniated patients were cultured within both hydrogels, for 1 up to 21 days. Dynamic mechanical analysis and biological characterization (calcein-AM staining, ATP and DNA quantification and PCR) were performed after specific times of culturing. A biocompatibility study was also performed in vivo, by subcutaneous implantation of acellular iGG-MA and phGG-MA hydrogels in Lewis rats for the period of 10 and 18 days. Tissue response to the hydrogels implantation was determined by histological analysis (haematoxylin-eosin staining). The in vitro study showed that both cell loading and culturing time do not have an effect on the mechanical properties of the hydrogels. Regarding their biological performance, the iGG-MA and phGG-MA hydrogels showed to be effective on supporting hIVD cells encapsulation and viability up to 21 days of culturing. Human IVD cells were homogeneously distributed within the hydrogels and maintained its round-shape morphology during culturing time. The in vivo biocompatibility study showed that iGG-MA and phGG-MA hydrogels do not elicit any deleterious effect, as denoted by the absence of necrosis and calcification, or acute inflammatory reaction. A thin fibrous capsule was observed around the implanted hydrogels. The results presented in this study indicate that the iGG-MA and phGG-MA hydrogels are stable in vitro and in vivo, support hIVD cells encapsulation and viability, and were found to be well-tolerated and non-cytotoxic in vivo, thus being potential candidates for NP regeneration