Use of bone marrow derived stem cells in trauma and orthopaedics: A review of current concepts

There is a considerable amount of interest in the futurerole of bone marrow-derived stem cells(BMDSCs) and tissue engineering techniques to manage conditions within the musculoskeletal system. Repair of soft tissue and bone defects, in the early stages of injury, may lead to a reduction in progression of symptoms. Furthermore, troublesome soft tissue injuries that are notoriously fraught with problems either in healing or function, could be augmented with such techniques. The aim of this review paper is to look at the advances in such strategies to tackle these problems and assess how BMDSCs, with the aid of growth factors and scaffolds, are being used in vitro, animal and even human models to treat problems within the field of trauma and orthopaedics. There is plenty of evidence that the results are encouraging and thus gaining momentum toward their use in human studies.

Role of nanotopography in the development of tissue engineered 3D organs and tissues using mesenchymal stem cells

Recent regenerative medicine and tissue engineering strategies(using cells, scaffolds, medical devices and gene therapy) have led to fascinating progress of translation of basic research towards clinical applications. In the past decade, great deal of research has focused on developing various three dimensional(3D) organs, such as bone, skin, liver, kidney and ear,using such strategies in order to replace or regenerate damaged organs for the purpose of maintaining or restoring organs' functions that may have been lost due to aging, accident or disease. The surface properties of a material or a device are key aspects in determining the success of the implant in biomedicine, as the majority of biological reactions in human body occur on surfaces or interfaces. Furthermore, it has been established in the literature that cell adhesion and proliferation are, to a great extent, influenced by the micro- and nanosurface characteristics of biomaterials and devices. In addition, it has been shown that the functions of stem cells, mesenchymal stem cells in particular, could be regulated through physical interaction with specific nanotopographical cues. Therefore, guided stem cell proliferation, differentiation and function are of great importance in the regeneration of 3D tissues and organs using tissue engineering strategies. This review will provide an update on the impact of nanotopography on mesenchymal stem cells for the purpose of developing laboratory-based 3D organs and tissues, as well as the most recent research and case studies on this topic.

Management of metal-on-metal hip implant patients: Who,when and how to revise?

The debate on how best to manage patients with metal-on-metal(MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed.

Analysing the outcome of surgery for chronic Achilles tendinopathy over the last 50 years

AIM: To determine an association between when the study was performed, the robustness of the study and the outcomes for insertional and non-insertional Achilles tendinopathy surgery. METHODS: We performed a systematic review in accordance with the PRISMA guidelines to assess the methodology of studies investigating the outcome of surgery in chronic Achilles tendinopathy over the last 50 years to identify any trends that would account for the variable results. The Coleman Methodology Scores were correlated with the reported percentage success rates and with the publication year to determine any trends using Pearson's correlation. RESULTS: We identified 62 studies published between 1964 and 2014 reporting on a total of 2923 surgically treated Achilles tendinopathies. The average followup time was 40 mo(range 5-204 mo), and the mean reported success rate was 83.5%(range 36%-100%). The Coleman Methodology Scores were highly reproducible(r = 0.99, P < 0.01), with a mean of 40.1(SD 18.9, range 2-79). We found a negative correlation between reported success rate and overall methodology scores(r =-0.40, P < 0.001), and a positive correlation between year of publication and overall methodology scores(r = 0.46, P < 0.001). CONCLUSION: We conclude that although the success rate of surgery for chronic Acilles tendinopathy described in the literature has fallen over the last 50 years, this is probably due to a more rigorous methodology of the studies.

Systematic review on the use of autologous matrix-induced chondrogenesis for the repair of articular cartilage defects in patients

AIM To systematically review the results of studies looking at autologous matrix-induced chondrogenesis(AMIC) in humans. METHODS A literature search was performed, adhering to the PRISMA guidelines, to review any studies using such techniques in humans. Our initial search retrieved 297 articles listed on MEDLINE, Google Scholar, CINHal and EMBASE. From these studies, 15 studies meeting the eligibility criteria were selected and formed the basis of our systematic review.RESULTS The study designs, surgical techniques and outcome measures varied between the studies. Although all studies reported improvements in patient outcome measures, this was not necessarily correlated with magnetic resonance imaging findings. Although there were many additional procedures performed, when AMIC was performed in isolation, the results tended to peak at 24 mo before declining. CONCLUSION Although short-term studies suggest improved patient reported outcomes with a variety of scaffolds, surgical techniques and rehabilitation regimes, the literature remains equivocal on whether the defect size and location, and patient factors affect the outcome. Patientbenefit appears to be maintained in the short-tomedium term but more high level studies with extensive and robust validated outcome measures should be conducted to evaluate the medium-and long-term effect of the AMIC procedure.

用于髋关节置换材料的优选(英文)

髋关节是人体关节中活动度最广泛、受力最复杂的关节之一,在日常活动中时刻经受着张力、压力、扭转力以及剪切力的考验。据英国国家健康系统（NHS）统计,每年至少有5万例髋关节置换手术,而假体平均使用寿命只有20~30年（NHS,2010）。骨质溶解及无菌性松动是影响髋关节置换术后假体存留以及导致二次翻修的主要原因,其产生机制是长期大量的磨损所产生的磨损微粒与假体发生生理反应,从而引起无菌性松动。为了避免此现象,专家学者试图找寻一种尽可能接近人体关节的生物材料,从而达到用高硬度、低刚度、低摩擦,高抗磨损、抗疲劳、抗腐蚀的材料制造人工关节假体的终极目标。如今市面上的各式髋臼-股骨头搭配组合皆为实现这一目标,如塑料与金属、塑料与陶瓷;金属与金属、金属与陶瓷;陶瓷与陶瓷等的结合。同时,生物材料业和生物工程业的逐步壮大及先进加工仪器的生产也推动着人工关节的发展。本文作者回顾了近50年来人工髋关节材料的发展,并对各组合进行了优劣对比;从患者的年龄、体形、身体状况及术后期望活动量等多角度进行了因人制宜的分析。同时介绍了不同材料配对的实验室模拟髋关节的磨损实验结果,以及术后远期关节功能、二次翻修率长期临床疗效,并对新兴假体组合进行了展望。

Biomimetic Collagen/Hydroxyapatite Composite Scaffolds: Fabrication and Characterizations

Biomimetic collagen/hydroxyapatite scaffolds have been prepared by microwave assisted co-titration of phosphorous acid-containing collagen solution and calcium hydroxide-containing solution. The resultant scaffolds have been characterised with respect to their mechanical properties, composition and microstructures. It was observed that the in situ precipitation process could combine collagen fibril formation and hydroxyapatite （HAp） formation in one process step. Collagen fibrils guided hydroxyapatite precipitation to form bone-mimic collagen/hydroxyapatite composite containing both intrafibrillar and interfibrillar hydroxyapatites. The mineral phase was determined as low crystalline calcium-deficient hydroxyapatite with calcium to phosphorus ratio （Ca/P） of 1.4. The obtained 1% （collagen/HAp = 75/25） scaffold has a porosity of 72% and a mean pore size of 69.4 ~tm. The incorporation of hydroxyapatite into collagen matrix improved the mechanical modulus of the scaffold significantly. This could be attributed to hydroxyapatite crystallites in collagen fibrils which restricted the deformation of the collagen fibril network, and the load transfer of the collagen to the higher modulus mineral component of the composite.

Quantifying the bearing surface wear of retrieved hip replacements

Accurate quantification of bearing material loss from retrieved metal-on-metal(MOM)hip replacements is key to understanding their failure.Geometric methods are currently the only means of estimating volumetric wear from retrieved implants and numerous contrasting approaches to obtain these measures have been published.Data collection strategies have been thoroughly discussed and refined to minimise the effect of error incurring factors;however,there is an opportunity to optimise the current methods of estimating the pre-wear geometry and,therefore,improve the accuracy of wear volume measurements.An automated analysis strategy to quantify volumetric wear is proposed in this study,which utilises the entire bearing surface to determine the implants pristine geometry.This involves the iterative removal of geometrically effected data points to optimise the fit and size of a perfect sphere.Once fitted,this reference geometry is compared with the measured data,in its entirety,to calculate the volume change representative of the quantity of material lost.Improving the reliability of this parameter could influence the care of a million patients that remain with MOM hip implants.Rigorous validation of this method will dominate future work,ensuring that the accuracy and reliability of this approach are sufficient to provide clinically meaningful data.