Cell therapies hold significant promise for the treatment of injured or diseased musculoskeletal tissues. However, despite advances in research, there is growing concern about the increasing number of clinical centres around the world that are making unwarranted claims or are performing risky biological procedures. Such providers have been known to recommend, prescribe, or deliver so called ‘stem cell’ preparations without sufficient data to support their true content and efficacy. In this annotation, we outline the current environment of stem cell-based treatments and the strategies of marketing directly to consumers. We also outline the difficulties in the regulation of these clinics and make recommendations for best practice and the identification and reporting of illegitimate providers.

Cite this article: Bone Joint J 2020;102-B(2):148–154

This annotation briefly reviews the history of artificial intelligence and machine learning in health care and orthopaedics, and considers the role it will have in the future, particularly with reference to statistical analyses involving large datasets.

Cite this article: Bone Joint J 2019;101-B:1476–1478

The Ankle Injury Management (AIM) trial was a pragmatic equivalence randomized controlled trial conducted at 24 hospitals in the United Kingdom that recruited 620 patients aged more than 60 years with an unstable ankle fracture. The trial compared the usual care pathway of early management with open reduction and internal fixation with initially attempting non-surgical management using close contact casting (CCC). CCC is a minimally padded cast applied by an orthopaedic surgeon after closed reduction in the operating theatre. The intervention groups had equivalent functional outcomes at six months and longer-term follow-up. However, potential barriers to using CCC as an initial form of treatment for these patients have been identified. In this report, the results of the AIM trial are summarized and the key issues are discussed in order to further the debate about the role of CCC. Evidence from the AIM trial supports surgeons considering conservative management by CCC as a treatment option for these patients. The longer-term follow-up emphasized that patients treated with CCC need careful monitoring in the weeks after its application to monitor maintenance of reduction.

Cite this article: Bone Joint J 2019;101-B:1472–1475.

There is good scientific rationale to support the use of growth factors to promote musculoskeletal tissue regeneration. However, the clinical effectiveness of platelet-rich plasma (PRP) and other blood-derived products has yet to be proven. Characterization and reporting of PRP preparation protocols utilized in clinical trials for the treatment of musculoskeletal disease is highly inconsistent, and the majority of studies do not provide sufficient information to allow the protocols to be reproduced. Furthermore, the reporting of blood-derived products in orthopaedics is limited by the multiple PRP classification systems available, which makes comparison of results between studies challenging. Several attempts have been made to characterize and classify PRP; however, no consensus has been reached, and there is lack of a comprehensive and validated classification. In this annotation, we outline existing systems used to classify preparations of PRP, highlighting their advantages and limitations. There remains a need for standardized universal nomenclature to describe biological therapies, as well as a comprehensive and reproducible classification system for autologous blood-derived products.

Cite this article: Bone Joint J 2019;101-B:891–896.

Informed consent is a very important part of surgical treatment. In this paper, we report a number of legal judgements in spinal surgery where there was no criticism of the surgical procedure itself. The fault that was identified was a failure to inform the patient of alternatives to, and material risks of, surgery, or overemphasizing the benefits of surgery. In one case, there was a promise that a specific surgeon was to perform the operation, which did not ensue. All of the faults in these cases were faults purely of the consenting process. In many cases, the surgeon claimed to have explained certain risks to the patient but was unable to provide proof of doing so. We propose a checklist that, if followed, would ensure that the surgeon would take their patients through the relevant matters but also, crucially, would act as strong evidence in any future court proceedings that the appropriate discussions had taken place. Although this article focuses on spinal surgery, the principles and messages are applicable to the whole of orthopaedic surgery.

Cite this article: Bone Joint J 2019;101-B:355–360.

Deep infection was identified as a serious complication in the earliest days of total hip arthroplasty. It was identified that airborne contamination in conventional operating theatres was the major contributing factor. As progress was made in improving the engineering of operating theatres, airborne contamination was reduced. Detailed studies were carried out relating airborne contamination to deep infection rates.

In a trial conducted by the United Kingdom Medical Research Council (MRC), it was found that the use of ultra-clean air (UCA) operating theatres was associated with a significant reduction in deep infection rates. Deep infection rates were further reduced by the use of a body exhaust system. The MRC trial also included a detailed microbiology study, which confirmed the relationship between airborne contamination and deep infection rates.

Recent observational evidence from joint registries has shown that in contemporary practice, infection rates remain a problem, and may be getting worse. Registry observations have also called into question the value of “laminar flow” operating theatres.

Observational evidence from joint registries provides very limited evidence on the efficacy of UCA operating theatres. Although there have been some changes in surgical practice in recent years, the conclusions of the MRC trial remain valid, and the use of UCA is essential in preventing deep infection.

There is evidence that if UCA operating theatres are not used correctly, they may have poor microbiological performance. Current UCA operating theatres have limitations, and further research is required to update them and improve their microbiological performance in contemporary practice.

Cite this article: Bone Joint J 2018;100-B:1264–9.

Our aim in this paper was to investigate the guidelines and laws governing informed consent in the English-speaking world. We noted a recent divergence from medical paternalism within the United Kingdom, highlighted by the Montgomery v Lanarkshire Health Board ruling of 2015. We investigated the situation in the United Kingdom, Australia, New Zealand, Canada, and the United States of America. We read the national guidance regarding obtaining consent for surgical intervention for each country. We used the references from this guidance to identify the laws that helped inform the guidance, and reviewed the court documents for each case.

There has been a trend towards a more patient-focused approach in consent in each country. Surgeons should be aware of the guidance and legal cases so that they can inform patients fully, and prevent legal problems if outdated practices are followed.

Cite this article: Bone Joint J 2018;100-B:687–92.

The posterior malleolus of the ankle is the object of increasing attention, with considerable enthusiasm for CT scanning and surgical fixation, as expressed in a recent annotation in The Bone & Joint Journal. Undoubtedly, fractures with a large posterior malleolar fragment that allow posterior talar subluxation from the mortise are served better by fixation. However, in all other situations, the existing literature does not support this widespread change in practice. The available biomechanical evidence shows that the posterior malleolus has little part to play in the stability or contact stresses of the ankle joint. Radiographic studies have not shown that CT scanning offers helpful information on pathoanatomical classification, case selection, or prognosis, or that scanning improves the likelihood of an adequate surgical reduction. Clinical studies have not shown any improvement in patient outcome after surgical fixation, and have confirmed that the inevitable consequence of increased intervention is an increased rate of complications. A careful and thoughtful evaluation of indications, risks, and benefits of this fashionable concept is required to ensure that we are deploying valuable resources with efficacy, and that we do no harm.

Cite this article: Bone Joint J 2018;100-B:566–9.

Unicompartmental knee arthroplasty (UKA) has numerous advantages over total knee arthroplasty (TKA) and one disadvantage, the higher revision rate. The best way to minimize the revision rate is for surgeons to use UKA for at least 20% of their knee arthroplasties. To achieve this, they need to learn and apply the appropriate indications and techniques. This would decrease the revision rate and increase the number of UKAs which were implanted, which would save money and patients would benefit from improved outcomes over their lifetime.

Cite this article: Bone Joint J 2018;100-B:432–5.

Aims

Periprosthetic joint infection (PJI) remains a challenging complication following total hip arthroplasty (THA). It is associated with high levels of morbidity, mortality and expense. Guidelines and protocols exist for the management of culture-positive patients. Managing culture-negative patients with a PJI poses a greater challenge to surgeons and the wider multidisciplinary team as clear guidance is lacking.

The development and pre-clinical evaluation of nano-texturised, biomimetic, surfaces of titanium (Ti) implants treated with titanium dioxide (TiO₂) nanotube arrays is reviewed. In vitro and in vivo evaluations show that TiO₂ nanotubes on Ti surfaces positively affect the osseointegration, cell differentiation, mineralisation, and anti-microbial properties. This surface treatment can be superimposed onto existing macro and micro porous Ti implants creating a surface texture that also interacts with cells at the nano level. Histology and mechanical pull-out testing of specimens in rabbits indicate that TiO₂ nanotubes improves bone bonding nine-fold (p = 0.008). The rate of mineralisation associated with TiO₂ nanotube surfaces is about three times that of non-treated Ti surfaces. In addition to improved osseointegration properties, TiO₂ nanotubes reduce the initial adhesion and colonisation of Staphylococcus epidermidis. Collectively, the properties of Ti implant surfaces enhanced with TiO₂ nanotubes show great promise.

Cite this article: Bone Joint J 2018;100-B(1 Supple A):9–16.

The posterior malleolus component of a fracture of the ankle is important, yet often overlooked. Pre-operative CT scans to identify and classify the pattern of the fracture are not used enough. Posterior malleolus fractures are not difficult to fix. After reduction and fixation of the posterior malleolus, the articular surface of the tibia is restored; the fibula is out to length; the syndesmosis is more stable and the patient can rehabilitate faster. There is therefore considerable merit in fixing most posterior malleolus fractures. An early post-operative CT scan to ensure that accurate reduction has been achieved should also be considered.

Cite this article: Bone Joint J 2017;99-B:1413–19.

Stable fractures of the ankle can be safely treated non-operatively. It is also gradually being recognised that the integrity of the ‘medial column’ is essential for the stability of the fracture. It is generally thought that bi- and tri-malleolar fractures are unstable, as are pronation external rotation injuries resulting in an isolated high fibular fracture (Weber type-C), where the deltoid ligament is damaged or the medial malleolus fractured. However, how best to identify unstable, isolated, trans-syndesmotic Weber type-B supination external rotation (SER) fractures of the lateral malleolus remains controversial.

We provide a rationale as to how to classify SER distal fibular fractures using weight-bearing radiographs, and how this can help guide the management of these common injuries.

Cite this article: Bone Joint J 2017;99-B:851–5.

The MAGnetic Expansion Control (MAGEC) system is used increasingly in the management of early-onset scoliosis. Good results have been published, but there have been recent reports identifying implant failures that may be associated with significant metallosis surrounding the implants. This article aims to present the current knowledge regarding the performance of this implant, and the potential implications and strategies that may be employed to identify and limit any problems.

We urge surgeons to apply caution to patient and construct selection; engage in prospective patient registration using a spine registry; ensure close clinical monitoring until growth has ceased; and send all explanted MAGEC rods for independent analysis.

The MAGEC system may be a good instrumentation system for the treatment of early-onset scoliosis. However, it is innovative and like all new technology, especially when deployed in a paediatric population, robust systems to assess long-term outcome are required to ensure that patient safety is maintained.

Cite this article: Bone Joint J 2017;99-B:708–13.

Aims

Treatment guidelines for atypical femoral fractures associated with bisphosphonates have not been established. We conducted a systematic review of the treatment of atypical femoral fractures first, to evaluate the outcomes of surgical fixation of complete atypical fractures and secondly, to assess whether prophylactic surgery is necessary for incomplete atypical fractures.

Aims

The purpose of this article was to review the current literature pertaining to the use of mobile compression devices (MCDs) for venous thromboembolism (VTE) following total joint arthroplasty (TJA), and to discuss the results of data from our institution.

Aims

To demonstrate, with concrete examples, the value of in-depth exploration and comparison of data published in National Joint Arthroplasty registry reports.

We recently published a paper comparing the incidence of adverse outcomes after unicompartmental and total knee arthroplasty (UKA and TKA). The conclusion of this study, which was in favour of UKA, was dismissed as “biased” in a review in Bone & Joint 360. Although this study is one of the least biased comparisons of UKA and TKA, this episode highlights the biases that exist both for and against UKA. In this review, we explore the different types of bias, particularly selection, reporting and measurement. We conclude that comparisons between UKA and TKA are open to bias. These biases can be so marked, particularly in comparisons based just on national registry data, that the conclusions can be misleading. For a fair comparison, data from randomised studies or well-matched, prospective observational cohort studies, which include registry data, are required, and multiple outcome measures should be used. The data of this type that already exist suggest that if UKA is used appropriately, compared with TKA, its advantages outweigh its disadvantages.

Cite this article: Bone Joint J 2017;99-B:12–15.

Aims

The optimal treatment for independent patients with a displaced intracapsular fracture of the hip remains controversial. The recognised alternatives are hemiarthroplasty and total hip arthroplasty. At present there is no established standard of care, with both types of arthroplasty being used in many centres.

Joint replacement of the hip and knee remain very satisfactory operations. They are, however, expensive. The actual manufacturing of the implant represents only 30% of the final cost, while sales and marketing represent 40%. Recently, the patents on many well established and successful implants have expired. Companies have started producing and distributing implants that purport to replicate existing implants with good long-term results.

The aims of this paper are to assess the legality, the monitoring and cost saving implications of such generic implants. We also assess how this might affect the traditional orthopaedic implant companies.

Cite this article: Bone Joint J 2016;98-B:892–900.

The results of the DRAFFT (distal radius acute fracture fixation trial) study, which compared volar plating with Kirschner (K-) wire fixation for dorsally displaced fractures of the distal radius, were published in August 2014. The use of K-wires to treat these fractures is now increasing, with a concomitant decline in the use of volar locking plates.

We provide a critical appraisal of the DRAFFT study and question whether surgeons have been unduly influenced by its headline conclusions.

Cite this article: Bone Joint J 2016;98-B:298–300.

Obesity is a worldwide epidemic that has both economic and health implications of enormous consequence. The obese patients tend to have earlier symptoms related to osteoarthritis, more peri-operative medical problems, higher rates of infection and more technical difficulties intra-operatively following hip and knee arthroplasty. Nevertheless, these patients have good long-term clinical outcomes and implant survival rates and are often some of the most satisfied patients after joint arthroplasty. Therefore, obese patients should not be denied surgery based on their weight alone.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):3–5.

The continual cycle of bone formation and resorption is carried out by osteoblasts, osteocytes, and osteoclasts under the direction of the bone-signaling pathway. In certain situations the host cycle of bone repair is insufficient and requires the assistance of bone grafts and their substitutes. The fundamental properties of a bone graft are osteoconduction, osteoinduction, osteogenesis, and structural support. Options for bone grafting include autogenous and allograft bone and the various isolated or combined substitutes of calcium sulphate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. Not all bone grafts will have the same properties. As a result, understanding the requirements of the clinical situation and specific properties of the various types of bone grafts is necessary to identify the ideal graft. We present a review of the bone repair process and properties of bone grafts and their substitutes to help guide the clinician in the decision making process.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):6–9.

Recently, several high impact randomised controlled trials have been published suggesting no greater benefit from orthopaedic surgery over conservative treatment, or limited surgical intervention. These studies can have profound effects on clinical practice, leading to the abandonment of previously widely-used operations.

How do surgeons who believe these operations are beneficial over conservative treatment rationalise these findings, and justify their use with hospital administrators and health care funders who require evidence for the value and efficacy of surgical treatment?

Cite this article: Bone Joint J 2015;97-B:1456–7.

Many aspects of total knee arthroplasty have changed since its inception. Modern prosthetic design, better fixation techniques, improved polyethylene wear characteristics and rehabilitation, have all contributed to a large change in revision rates. Arthroplasty patients now expect longevity of their prostheses and demand functional improvement to match. This has led to a re-examination of the long-held belief that mechanical alignment is instrumental to a successful outcome and a focus on restoring healthy joint kinematics. A combination of kinematic restoration and uncemented, adaptable fixation may hold the key to future advances.

Cite this article: Bone Joint J 2015;97-B(10 Suppl A):16–19.

Despite being one of the most common orthopaedic operations, it is still not known how many arthroscopies of the knee must be performed during training in order to develop the skills required to become a Consultant. A total of 54 subjects were divided into five groups according to clinical experience: Novices (n = 10), Junior trainees (n = 10), Registrars (n = 18), Fellows (n = 10) and Consultants (n = 6). After viewing an instructional presentation, each subject performed a simple diagnostic arthroscopy of the knee on a simulator with visualisation and probing of ten anatomical landmarks. Performance was assessed using a validated global rating scale (GRS). Comparisons were made against clinical experience measured by the number of arthroscopies which had been undertaken, and ROC curve analysis was used to determine the number of procedures needed to perform at the level of the Consultants.

There were marked differences between the groups. There was significant improvement in performance with increasing experience (p < 0.05).

ROC curve analysis identified that approximately 170 procedures were required to achieve the level of skills of a Consultant.

We suggest that this approach to identify what represents the level of surgical skills of a Consultant should be used more widely so that standards of training are maintained through the development of an evidenced-based curriculum.

Cite this article: Bone Joint J 2015;97-B:1309–15.

In this paper, we critically appraise the recent publication of the United Kingdom Heel Fracture Trial, which concluded that when patients with an absolute indication for surgery were excluded, there was no advantage of surgical over non-surgical treatment in the management of calcaneal fractures.

We believe that selection bias in that study did not permit the authors to reach a firm conclusion that surgery was not justified for most intra-articular calcaneal fractures.

Cite this article: Bone Joint J 2015;97-B:880–2.

The maintenance of quality and integrity in clinical and basic science research depends upon peer review. This process has stood the test of time and has evolved to meet increasing work loads, and ways of detecting fraud in the scientific community. However, in the 21st century, the emphasis on evidence-based medicine and good science has placed pressure on the ways in which the peer review system is used by most journals.

This paper reviews the peer review system and the problems it faces in the digital age, and proposes possible solutions.

Cite this article: Bone Joint J 2014;96-B:436–41.

With the established success of the National Joint Registry and the emergence of a range of new national initiatives for the capture of electronic data in the National Health Service, orthopaedic surgery in the United Kingdom has found itself thrust to the forefront of an information revolution. In this review we consider the benefits and threats that this revolution poses, and how orthopaedic surgeons should marshal their resources to ensure that this is a force for good.

An international faculty of orthopaedic surgeons presented their work on the current challenges in hip surgery at the London Hip Meeting which was attended by over 400 delegates. The topics covered included femoroacetabular impingement, thromboembolic phenomena associated with hip surgery, bearing surfaces (including metal-on-metal articulations), outcomes of hip replacement surgery and revision hip replacement. We present a concise report of the current opinions on hip surgery from this meeting with appropriate references to the current literature.

Radiological imaging is necessary in a wide variety of trauma and elective orthopaedic operations. The evolving orthopaedic workforce includes an increasing number of pregnant workers. Current legislation in the United Kingdom, Europe and United States allows them to choose their degree of participation, if any, with fluoroscopic procedures. For those who wish to engage in radiation-prone procedures, specific regulations apply to limit the radiation dose to the pregnant worker and unborn child.

This paper considers those aspects of radiation protection, the potential effects of exposure to radiation in pregnancy and the dose of radiation from common orthopaedic procedures, which are important for safe clinical practice.

Rupture of the tendo Achillis is a common injury with a rising incidence. Traditionally the key question following this injury has been whether or not to operate. However a contemporary Cochrane review highlighted that the method of rehabilitation may also have an important contribution to the outcome. Since this review, various early weight-bearing rehabilitation protocols have been described. Currently evidence points to the use of early functional rehabilitation, regardless of operative or non-operative management. However, there is no consensus on which exact functional rehabilitation protocol should be used. Future research should be directed towards improving our understanding of how the different rehabilitative components interact in the tendo Achillis as it heals.

There is no unified national training system for orthopaedic surgeons in China. With such rapid progress in many aspects of life in China, there is an imminent need for improvement in the training of orthopaedic specialists. Since 2003 the orthopaedic community in Hong Kong has been working in collaboration with their colleagues in mainland China to develop a training system for orthopaedic surgery. We adopted the system from the Royal College of Surgeons of Edinburgh (RCSEd), setting up a trial centre in the Beijing Jishuitan hospital in 2006, with trainers and trainees attaining the standards set by RCSEd and the Hong Kong College of Orthopaedic Surgeons (HKCOS). This trial is ongoing, with the success of two trainees who passed the exit examination in 2010 and became the first Chinese orthopaedic surgeons with a joint fellowship of both the RCSEd and the HKCOS. Following this inaugural success, we are confident that China will develop a training system for orthopaedic surgeons to a consistently high international standard.

From a global point of view, chronic haematogenous osteomyelitis in children remains a major cause of musculoskeletal morbidity. We have reviewed the literature with the aim of estimating the scale of the problem and summarising the existing research, including that from our institution. We have highlighted areas where well-conducted research might improve our understanding of this condition and its treatment.

This brief annotation summarises the particular contributions made by the annual Edinburgh International Trauma Symposium in various areas of research into aspects of orthopaedic trauma and the management of acutely injured patients, during the 25 years since its establishment.

Multicentre clinical trials in trauma care are gaining prominence as a means of generating good-quality evidence to inform and influence clinical practice. We believe multicentre trials have an important role to play in supporting evidence-based practice, and further investment in such trials is justified.

The Canadian Orthopaedic Trauma Society was started in an endeavour to answer the difficult problem of obtaining enough patients to perform top-quality research into fractures. By maintaining a high standard, including randomised study design, inclusivity, open discussion among surgeons and excellent long-term follow-up, this group has become a leader in the orthopaedic research community. This annotation describes the short history, important components and spirit necessary to build a research community or team which will function well despite the difficult research environment facing individual surgeons.

Aseptic loosening of the acetabular component continues to be the most common indication for revision of total hip replacements in younger patients. Early in the evolution of the cemented hip, arthroplasty surgeons switched from removal to retention of the acetabular subchondral bone plate, theorising that unfavourable mechanical forces were the cause of loosening at the bone-cement interface.

It is now known that the cause of aseptic loosening is probably biological rather than mechanical and removing the subchondral bone plate may enhance biological fixation of cement to bone. With this in mind, perhaps it is time to revive removal of the subchondral bone as a standard part of acetabular preparation.

In a systematic review, reports from national registers and clinical studies were identified and analysed with respect to revision rates after joint replacement, which were calculated as revisions per 100 observed component years.

After primary hip replacement, a mean of 1.29 revisions per 100 observed component years was seen. The results after primary total knee replacement are 1.26 revisions per 100 observed component years, and 1.53 after medial unicompartmental replacement. After total ankle replacement a mean of 3.29 revisions per 100 observed component years was seen.

The outcomes of total hip and knee replacement are almost identical. Revision rates of about 6% after five years and 12% after ten years are to be expected.

National registers compare implants by their revision rates, but the validity of the method has never been assessed. The New Zealand Joint Registry publishes clinical outcomes (Oxford knee scores, OKS) alongside revision rates, allowing comparison of the two measurements. In the two types of knee replacement, unicompartmental (UKR) had a better knee score than total replacement (TKR), but the revision rate of the former was nearly three times higher than that of the latter. This was because the sensitivity of the revision rate to clinical failure was different for the two implants. For example, of knees with a very poor outcome (OKS < 20 points), only about 12% of TKRs were revised compared with about 63% of UKRs with similar scores.

Revision therefore is not an objective measurement and should not be used to compare these two types of implant. Furthermore, revision is much less sensitive than the OKS to clinical failure in both types and therefore exaggerates the success of knee replacements, particularly of TKR.

This paper outlines the history of advances made in the treatment of open fractures that have occurred during wartime.

We review the history and literature of hip resurfacing arthroplasty. Resurfacing and the science behind it continues to evolve. Recent results, particularly from the national arthroplasty registers, have spread disquiet among both surgeons and patients. A hip resurfacing arthroplasty is not a total hip replacement, but should perhaps be seen as a means of delaying it. The time when hip resurfacing is offered to a patient may be different from that for a total hip replacement. The same logic can apply to the timing of revision surgery. Consequently, the comparison of resurfacing with total hip replacement may be a false one. Nevertheless, the need for innovative solutions for young arthroplasty patients is clear. Total hip replacement can be usefully delayed in many of these patients by the use of hip resurfacing arthroplasty.

The 2010 Fellows undertook a six-week journey through centres of orthopaedic excellence along the East Coast of Canada and the United States. What we learned and gained from the experience and each other is immeasurable, but five areas particularly stand out; education, research, service delivery, financial insights and professional development.

The credibility and creativity of an author may be gauged by the number of scientific papers he or she has published, as well as the frequency of citations of a particular paper reflecting the impact of the data on the area of practice. The object of this study was to identify and analyse the qualities of the top 100 cited papers in orthopaedic surgery. The database of the Science Citation Index of the Institute for Scientific Information (1945 to 2008) was used. A total of 1490 papers were cited more than 100 times, with the top 100 being subjected to further analysis. The majority originated in the United States, followed by the United Kingdom. The top 100 papers were published in seven specific orthopaedic journals.

Analysis of the most-cited orthopaedic papers allows us a unique insight into the qualitites, characteristics and clinical innovations required for a paper to attain ‘classic’ status.

Fluoronavigation is an image-guided technology which uses intra-operative fluoroscopic images taken under a real-time tracking system and registration to guide surgical procedures. With the skeleton and the instrument registered, guidance under an optical tracking system is possible, allowing fixation of the fracture and insertion of an implant. This technology helps to minimise exposure to x-rays, providing multiplanar views for monitoring and accurate positioning of implants. It allows real-time interactive quantitative data for decision-making and expands the application of minimally invasive surgery. In orthopaedic trauma its use can be further enhanced by combining newer imaging technologies such as intra-operative three-dimensional fluoroscopy and optical image guidance, new advances in software for fracture reduction, and new tracking mechanisms using electromagnetic technology. The major obstacles for general and wider applications are the inability to track individual fracture fragments, no navigated real-time fracture reduction, and the lack of an objective assessment method for cost-effectiveness.

We believe that its application will go beyond the operating theatre and cover all aspects of patient management, from pre-operative planning to intra-operative guidance and postoperative rehabilitation.

Orthopaedic surgery is in an exciting transitional period as modern surgical interventions, implants and scientific developments are providing new therapeutic options. As advances in basic science and technology improve our understanding of the pathology and repair of musculoskeletal tissue, traditional operations may be replaced by newer, less invasive procedures which are more appropriately targeted at the underlying pathophysiology. However, evidence-based practice will remain a basic requirement of care. Orthopaedic surgeons can and should remain at the forefront of the development of novel therapeutic interventions and their application. Progression of the potential of bench research into an improved array of orthopaedic treatments in an effective yet safe manner will require the development of a subgroup of specialists with extended training in research to play an important role in bridging the gap between laboratory science and clinical practice. International regulations regarding the introduction of new biological treatments will place an additional burden on the mechanisms of this translational process, and orthopaedic surgeons who are trained in science, surgery and the regulatory environment will be essential. Training and supporting individuals with these skills requires special consideration and discussion by the orthopaedic community.

In this paper we review some traditional approaches to the integration of orthopaedic science and surgery, the therapeutic potential of current regenerative biomedical science for cartilage repair and ways in which we may develop surgeons with the skills required to translate scientific discovery into effective and properly assessed orthopaedic treatments.

In comparing or assessing methods of treatment it is vital that the appropriate number of patients is selected in order to ensure that the conclusions drawn are statistically viable. This annotation describes the relevance of a statistical power analysis in the context of hypothesis testing to the determination of the optimal sample size of a study. The power of the test indicates how likely it is that the test will correctly produce a statistically significant result.

There are three basic concepts that are important to the biomechanics of pedicle screw-based instrumentation. First, the outer diameter of the screw determines pullout strength, while the inner diameter determines fatigue strength. Secondly, when inserting a pedicle screw, the dorsal cortex of the spine should not be violated and the screws on each side should converge and be of good length. Thirdly, fixation can be augmented in cases of severe osteoporosis or revision.

A trajectory parallel or caudal to the superior endplate can minimise breakage of the screw from repeated axial loading. Straight insertion of the pedicle screw in the mid-sagittal plane provides the strongest stability.

Rotational stability can be improved by adding transverse connectors. The indications for their use include anterior column instability, and the correction of rotational deformity.

Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases.

The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.

Following the publication in 2007 of the guidelines from the National Institute for Health and Clinical Excellence (NICE) for prophylaxis against venous thromboembolism (VTE) for patients undergoing surgery, concerns were raised by British orthopaedic surgeons as to the appropriateness of the recommendations for their clinical practice. In order to address these concerns NICE and the British Orthopaedic Association agreed to engage a representative panel of orthopaedic surgeons in the process of developing expanded VTE guidelines applicable to all patients admitted to hospital. The functions of this panel were to review the evidence and to consider the applicability and implications in orthopaedic practice in order to advise the main Guideline Development Group in framing recommendations.

The panel considered both direct and indirect evidence of the safety and efficacy, the cost-effectiveness of prophylaxis and its implication in clinical practice for orthopaedic patients. We describe the process of selection of the orthopaedic panel, the evidence considered and the contribution of the panel to the latest guidelines from NICE on the prophylaxis against VTE, published in January 2010.