Orthopaedic surgeons are currently faced with an overwhelming number of choices surrounding total knee arthroplasty (TKA), not only with the latest technologies and prostheses, but also fundamental decisions on alignment philosophies. From ‘mechanical’ to ‘adjusted mechanical’ to ‘restricted kinematic’ to ‘unrestricted kinematic’ — and how constitutional alignment relates to these — there is potential for ambiguity when thinking about and discussing such concepts. This annotation summarizes the various alignment strategies currently employed in TKA. It provides a clear framework and consistent language that will assist surgeons to compare confidently and contrast the concepts, while also discussing the latest opinions about alignment in TKA. Finally, it provides suggestions for applying consistent nomenclature to future research, especially as we explore the implications of 3D alignment patterns on patient outcomes. Cite this article: Bone Joint J 2023;105-B(2):102–108

Prophylactic antibiotics are important in reducing the risk of periprosthetic joint infection (PJI) following total knee arthroplasty. Their effectiveness depends on the choice of antibiotic and the optimum timing of their administration, to ensure adequate tissue concentrations. Cephalosporins are typically used, but an increasing number of resistant organisms are causing PJI, leading to the additional use of vancomycin. There are difficulties, however, with the systemic administration of vancomycin including its optimal timing, due to the need for prolonged administration, and potential adverse reactions. Intraosseous regional administration distal to a tourniquet is an alternative and attractive mode of delivery due to the ease of obtaining intraosseous access. Many authors have reported the effectiveness of intraosseous prophylaxis in achieving higher concentrations of antibiotic in the tissues compared with intravenous administration, providing equal or enhanced prophylaxis while minimizing adverse effects. This annotation describes the technique of intraosseous administration of antibiotics and summarizes the relevant clinical literature to date. Cite this article: Bone Joint J 2023;105-B(11):1135–1139

As advancements in total knee arthroplasty progress at an exciting pace, two areas are of special interest, as they directly impact implant design and surgical decision making. Knee morphometry considers the three-dimensional shape of the articulating surfaces within the knee joint, and knee phenotyping provides the ability to categorize alignment into practical groupings that can be used in both clinical and research settings. This annotation discusses the details of these concepts, and the ways in which they are helping us better understand the individual subtleties of each patient’s knee. Cite this article: Bone Joint J 2024;106-B(12):1363–1368

The aim of mechanical alignment in total knee arthroplasty is to align all knees into a fixed neutral position, even though not all knees are the same. As a result, mechanical alignment often alters a patient’s constitutional alignment and joint line obliquity, resulting in soft-tissue imbalance. This annotation provides an overview of how the Coronal Plane Alignment of the Knee (CPAK) classification can be used to predict imbalance with mechanical alignment, and then offers practical guidance for bone balancing, minimizing the need for soft-tissue releases. Cite this article: Bone Joint J 2024;106-B(6):525–531

Total hip and knee arthroplasty (THA, TKA) are largely successful procedures; however, both have variable outcomes, resulting in some patients being dissatisfied with the outcome. Surgeons are turning to technologies such as robotic-assisted surgery in an attempt to improve outcomes. Robust studies are needed to find out if these innovations are really benefitting patients. The Robotic Arthroplasty Clinical and Cost Effectiveness Randomised Controlled Trials (RACER) trials are multicentre, patient-blinded randomized controlled trials. The patients have primary osteoarthritis of the hip or knee. The operation is Mako-assisted THA or TKA and the control groups have operations using conventional instruments. The primary clinical outcome is the Forgotten Joint Score at 12 months, and there is a built-in analysis of cost-effectiveness. Secondary outcomes include early pain, the alignment of the components, and medium- to long-term outcomes. This annotation outlines the need to assess these technologies and discusses the design and challenges when conducting such trials, including surgical workflows, isolating the effect of the operation, blinding, and assessing the learning curve. Finally, the future of robotic surgery is discussed, including the need to contemporaneously introduce and evaluate such technologies. Cite this article: Bone Joint J 2024;106-B(2):114–120

Periprosthetic joint infection (PJI) represents a complex challenge in orthopaedic surgery associated with substantial morbidity and healthcare expenditures. The debridement, antibiotics, and implant retention (DAIR) protocol is a viable treatment, offering several advantages over exchange arthroplasty. With the evolution of treatment strategies, considerable efforts have been directed towards enhancing the efficacy of DAIR, including the development of a phased debridement protocol for acute PJI management. This article provides an in-depth analysis of DAIR, presenting the outcomes of single-stage, two-stage, and repeated DAIR procedures. It delves into the challenges faced, including patient heterogeneity, pathogen identification, variability in surgical techniques, and antibiotics selection. Moreover, critical factors that influence the decision-making process between single- and two-stage DAIR protocols are addressed, including team composition, timing of the intervention, antibiotic regimens, and both anatomical and implant-related considerations. By providing a comprehensive overview of DAIR protocols and their clinical implications, this annotation aims to elucidate the advancements, challenges, and potential future directions in the application of DAIR for PJI management. It is intended to equip clinicians with the insights required to effectively navigate the complexities of implementing DAIR strategies, thereby facilitating informed decision-making for optimizing patient outcomes.

Cite this article: Bone Joint J 2024;106-B(12):1377–1384.

Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved. Cite this article: Bone Joint J 2020;102-B(3):276–279

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

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

Recent publications have drawn attention to the fact that some brands of joint replacement may contain variants which perform significantly worse (or better) than their ‘siblings’. As a result, the National Joint Registry has performed much more detailed analysis on the larger families of knee arthroplasties in order to identify exactly where these differences may be present and may hitherto have remained hidden. The analysis of the Nexgen knee arthroplasty brand identified that some posterior-stabilized combinations have particularly high revision rates for aseptic loosening of the tibia, and consequently a medical device recall has been issued for the Nexgen ‘option’ tibial component which was implicated. More elaborate signal detection is required in order to identify such variation in results in a routine fashion if patients are to be protected from such variation in outcomes between closely related implant types.

Cite this article: Bone Joint J 2023;105-B(3):221–226.

The subject of noise in the operating theatre was recognized as early as 1972 and has been compared to noise levels on a busy highway. While noise-induced hearing loss in orthopaedic surgery specifically has been recognized as early as the 1990s, it remains poorly studied. As a result, there has been renewed focus in this occupational hazard. Noise level is typically measured in decibels (dB), whereas noise adjusted for human perception uses A-weighted sound levels and is expressed in dBA. Mean operating theatre noise levels range between 51 and 75 dBA, with peak levels between 80 and 119 dBA. The greatest sources of noise emanate from powered surgical instruments, which can exceed levels as high as 140 dBA. Newer technology, such as robotic-assisted systems, contribute a potential new source of noise. This article is a narrative review of the deleterious effects of prolonged noise exposure, including noise-induced hearing loss in the operating theatre team and the patient, intraoperative miscommunication, and increased cognitive load and stress, all of which impact the surgical team’s overall performance. Interventions to mitigate the effects of noise exposure include the use of quieter surgical equipment, the implementation of sound-absorbing personal protective equipment, or changes in communication protocols. Future research endeavours should use advanced research methods and embrace technological innovations to proactively mitigate the effects of operating theatre noise.

Cite this article: Bone Joint J 2024;106-B(10):1039–1043.

Periprosthetic femoral fractures are increasing in incidence, and typically occur in frail elderly patients. They are similar to pathological fractures in many ways. The aims of treatment are the same, including 'getting it right first time' with a single operation, which allows immediate unrestricted weightbearing, with a low risk of complications, and one that avoids the creation of stress risers locally that may predispose to further peri-implant fracture. The surgical approach to these fractures, the associated soft-tissue handling, and exposure of the fracture are key elements in minimizing the high rate of complications. This annotation describes the approaches to the femur that can be used to facilitate the surgical management of peri- and interprosthetic fractures of the femur at all levels using either modern methods of fixation or revision arthroplasty.

Cite this article: Bone Joint J 2023;105-B(6):593–601.

Periprosthetic joint infection (PJI) remains an extremely challenging complication. We have focused on this issue more over the last decade than previously, but there are still many unanswered questions. We now have a workable definition that everyone should align to, but we need to continue to focus on identifying the organisms involved. Surgical strategies are evolving and care is becoming more patient-centred. There are some good studies under way. There are, however, still numerous problems to resolve, and the challenge of PJI remains a major one for the orthopaedic community. This annotation provides some up-to-date thoughts about where we are, and the way forward. There is still scope for plenty of research in this area.

Cite this article: Bone Joint J 2022;104-B(11):1193–1195.

Artificial intelligence (AI) is, in essence, the concept of ‘computer thinking’, encompassing methods that train computers to perform and learn from executing certain tasks, called machine learning, and methods to build intricate computer models that both learn and adapt, called complex neural networks. Computer vision is a function of AI by which machine learning and complex neural networks can be applied to enable computers to capture, analyze, and interpret information from clinical images and visual inputs. This annotation summarizes key considerations and future perspectives concerning computer vision, questioning the need for this technology (the ‘why’), the current applications (the ‘what’), and the approach to unlocking its full potential (the ‘how’).

Cite this article: Bone Joint J 2022;104-B(8):911–914.

Artificial intelligence and machine-learning analytics have gained extensive popularity in recent years due to their clinically relevant applications. A wide range of proof-of-concept studies have demonstrated the ability of these analyses to personalize risk prediction, detect implant specifics from imaging, and monitor and assess patient movement and recovery. Though these applications are exciting and could potentially influence practice, it is imperative to understand when these analyses are indicated and where the data are derived from, prior to investing resources and confidence into the results and conclusions. In this article, we review the current benefits and potential limitations of machine-learning for the orthopaedic surgeon with a specific emphasis on data quality.

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

The use of tourniquets in lower limb trauma surgery to control bleeding and improve the surgical field is a long established practice. In this article, we review the evidence relating to harms and benefits of tourniquet use in lower limb fracture fixation surgery and report the results of a survey on current tourniquet practice among trauma surgeons in the UK.