Author's response.

Many thanks for your interest in our article. We agree on the issue of multimodal surveys and, certainly, for non-responders, a multimodal survey is a good tool. The other points mentioned in your letter have already been covered in our article. Finally, we do not agree on the issue of surveys being time consuming but not expensive. Somebody is paying for the time

Effect of foliar sprays of uracil, xanthine and caffeine on the nucleic acid and protein content of leaves and fruiting of Thompson Seedless grapes

Thompson Seedless vines were sprayed with aqueous solutions of uracil, xanthine and caffeine at 50 ppm twice during the growing season: when the shoots were 30-40 cm long and again a week later. Uracil was found to be more effective than caffeine and xanthine in its promoting influence on the synthesis of RNA and fruitfulness. The sugar content of the berries on the treated vines was increased but there was little change in acid content. The time of fruit maturity was not affected.Der Einfluß von Sprühbehandlungen mit Uracil, Xanthin und Coffein auf den Nukleinsäure- und Proteingehalt der Blätter sowie den Fruchtansatz bei  ThompsonSeedless-RebenReben der Sorte Thompson Seedless wurden mit wässrigen Lösungen von Uracil, Xanthin und Coffein (50 ppm) zweimal während der Wachstumsperiode gesprüht, und zwar bei einer Trieblänge von 30-40 cm Länge und eine Woche später.Uracil förderte die DNS- und Proteinsynthese sowie die Fruchtbarkeit in stärkerem Maße als Coffein und Xanthin. Der Zuckergehalt der Beeren war gegenüber der Kontrolle erhöht, der Säuregehalt jedoch nur wenig verändert. Der Zeitpunkt der Fruchtreife wurde nicht beeinflußt

Avoiding iatrogenic injury during portal placement in hip arthroscopy.

Hip arthroscopy has gained immense popularity in the treatment of many intra and extra-articular pathologies in and around the hip joint. The anterolateral portal is the most common portal used to establish access at arthroscopy and being the first, it has to be placed blindly under image intensifier guidance. The subsequent portals are placed under direct arthroscopic visualisation. Iatrogenic acetabular labral injury (IALI) has been reported to occur during the first portal placement and its incidence varies from 0.67% to 20%.1–3 We present an easy technique to prevens IALI

Development of Machine-Learning Algorithms to Predict Attainment of Minimal Clinically Important Difference After Hip Arthroscopy for Femoroacetabular Impingement Yield Fair Performance and Limited Clinical Utility

\ua9 2023 The Author(s). Purpose: To determine whether machine learning (ML) techniques developed using registry data could predict which patients will achieve minimum clinically important difference (MCID) on the International Hip Outcome Tool 12 (iHOT-12) patient-reported outcome measures (PROMs) after arthroscopic management of femoroacetabular impingement syndrome (FAIS). And secondly to determine which preoperative factors contribute to the predictive power of these models. Methods: A retrospective cohort of patients was selected from the UK\u27s Non-Arthroplasty Hip Registry. Inclusion criteria were a diagnosis of FAIS, management via an arthroscopic procedure, and a minimum follow-up of 6 months after index surgery from August 2012 to June 2021. Exclusion criteria were for non-arthroscopic procedures and patients without FAIS. ML models were developed to predict MCID attainment. Model performance was assessed using the area under the receiver operating characteristic curve (AUROC). Results: In total, 1,917 patients were included. The random forest, logistic regression, neural network, support vector machine, and gradient boosting models had AUROC 0.75 (0.68-0.81), 0.69 (0.63-0.76), 0.69 (0.63-0.76), 0.70 (0.64-0.77), and 0.70 (0.64-0.77), respectively. Demographic factors and disease features did not confer a high predictive performance. Baseline PROM scores alone provided comparable predictive performance to the whole dataset models. Both EuroQoL 5-Dimension 5-Level and iHOT-12 baseline scores and iHOT-12 baseline scores alone provided AUROC of 0.74 (0.68-0.80) and 0.72 (0.65-0.78), respectively, with random forest models. Conclusions: ML models were able to predict with fair accuracy attainment of MCID on the iHOT-12 at 6-month postoperative assessment. The most successful models used all patient variables, all baseline PROMs, and baseline iHOT-12 responses. These models are not sufficiently accurate to warrant routine use in the clinic currently. Level of Evidence: Level III, retrospective cohort design; prognostic study

Can hip arthroscopy in the presence of arthritis delay the need for hip arthroplasty?

Hip arthroscopy for joint preservation surgery has grown immensely over the last two decades. There is now an increasing trend to try and expand the role of hip arthroscopy to include patients of an older age or perhaps even with signs of arthritis, instead of the established patient group of young adults with mechanical symptoms or serious athletes. But how much of this growth is really justified? Once arthritis is apparent, the arthroscopic procedures needed to try and limit progression of the disease are likely to be different to those needed in young adult non-arthritic hips. Similarly, the expectation of results following an arthroscopic procedure in an older adult with arthritis must also be different. With an almost 5-fold increase in conversion rate from arthroscopy to arthroplasty in the over 50s population, arthroscopy in arthritis is a different procedure, with a different outcome, to arthroscopy in young adults with no evidence of osteoarthritis. This article takes a closer inspection at outcomes following hip arthroscopy in the older population particularly in those with evidence of early arthritis. This paper does not attempt to make recommendations in other diagnoses such as inflammatory arthritis or other secondary arthritides. It must be considered that hip arthroscopy is not a benign intervention: as well as the surgical risks, the lengthy rehabilitation period should be factored into the equation. Although the nature of surgeons is to find new techniques and push boundaries, we highlight the need for caution in undertaking arthroscopic intervention when arthritis is already apparent at presentation

The case for ceramic-on-polyethylene as the preferred bearing for a young adult hip replacement

The optimum choice of bearing surfaces in total hip arthroplasty, particularly in the younger and more active patient, remains controversial. Despite several studies demonstrating good long-term results for the metal-on-polyethylene articulation, there has been a recent vogue towards the utilisation of hard-on-hard bearings for younger patients due, in part, to concerns regarding polyethylene induced osteolysis. However, well-documented complications concerning metal-on-metal bearings and the risk of fracture in ceramic-on-ceramic bearings have raised concerns regarding the principle of the hard-on-hard bearing in the active patient. With recent technological advancements in the manufacture of both polyethylene and alumina ceramics, the in vitro properties of each material with regards to strength and toughness have been significantly improved. In addition, ceramic femoral heads have consistently been shown to produce less in vivo polyethylene wear than similar sized metal heads. This paper aims to critically review the biomechanical, in vivo and clinical studies related to the use of the ceramic on polyethylene bearing, and highlights its potential use as the preferred bearing for a young adult hip replacement

Does virtual reality simulation have a role in training trauma and orthopaedic surgeons?

AIMS: The aim of this study was to assess the current evidence relating to the benefits of virtual reality (VR) simulation in orthopaedic surgical training, and to identify areas of future research. MATERIALS AND METHODS: A literature search using the MEDLINE, Embase, and Google Scholar databases was performed. The results' titles, abstracts, and references were examined for relevance. RESULTS: A total of 31 articles published between 2004 and 2016 and relating to the objective validity and efficacy of specific virtual reality orthopaedic surgical simulators were identified. We found 18 studies demonstrating the construct validity of 16 different orthopaedic virtual reality simulators by comparing expert and novice performance. Eight studies have demonstrated skill acquisition on a simulator by showing improvements in performance with repeated use. A further five studies have demonstrated measurable improvements in operating theatre performance following a period of virtual reality simulator training. CONCLUSION: The demonstration of 'real-world' benefits from the use of VR simulation in knee and shoulder arthroscopy is promising. However, evidence supporting its utility in other forms of orthopaedic surgery is lacking. Further studies of validity and utility should be combined with robust analyses of the cost efficiency of validated simulators to justify the financial investment required for their use in orthopaedic training. Cite this article: Bone Joint J 2018;100-B:559-65

Current concepts in the diagnosis and management of extra-articular hip impingement syndromes

Purpose Extra-articular hip impingement syndromes encompass a group of conditions that have previously been an unrecognised source of pain in the hip and on occasion been associated with intra-articular hip impingement as well. As arthroscopic techniques for the hip continue to evolve, the importance of these conditions has been recognised recently and now form an important part of the differential of an individual presenting with hip pain. The aim of this article, therefore, is to provide the reader with an evidence-based and comprehensive update of these syndromes. Methods By reviewing past literature, the anatomy, pathophysiology, clinical features and the management of the five common extra-articular hip impingement syndromes were described. Results The common extra-articular impingement syndromes are: 1) Ischiofemoral impingement: quadratus femoris muscle becomes compressed between the lesser trochanter and the ischial tuberosity. 2) Subspine impingement: mechanical conflict occurs between an enlarged or malorientated anterior inferior iliac spine and the distal anterior femoral neck. 3) Iliopsoas impingement: mechanical conflict occurs between the iliopsoas muscle and the labrum, resulting in distinct anterior labral pathology. 4) Deep gluteal syndrome: pain occurs in the buttock due to the entrapment of the sciatic nerve in the deep gluteal space. 5) Pectineofoveal impingement: pain occurs when the medial synovial fold impinges against overlying soft tissue, primarily the zona orbicularis. Knowledge for these syndromes still remains limited for reasons mostly relating to their low prevalence and their co-existence with typical femoro-acetabular impingement. Conclusions The knowledge of extra-articular hip impingement syndromes is essential and should form a part of the differential diagnoses alongside intra-articular pathology including femoro-acetabular impingement particularly in the younger patient with a non-arthritic hip

Negative pressure wound therapy for managementof the surgical incision in orthopaedic surgery: A review of evidence and mechanisms for an emerging indication.

OBJECTIVES: The period of post-operative treatment before surgical wounds are completely closed remains a key window, during which one can apply new technologies that can minimise complications. One such technology is the use of negative pressure wound therapy to manage and accelerate healing of the closed incisional wound (incisional NPWT). METHODS: We undertook a literature review of this emerging indication to identify evidence within orthopaedic surgery and other surgical disciplines. Literature that supports our current understanding of the mechanisms of action was also reviewed in detail. RESULTS: A total of 33 publications were identified, including nine clinical study reports from orthopaedic surgery; four from cardiothoracic surgery and 12 from studies in abdominal, plastic and vascular disciplines. Most papers (26 of 33) had been published within the past three years. Thus far two randomised controlled trials - one in orthopaedic and one in cardiothoracic surgery - show evidence of reduced incidence of wound healing complications after between three and five days of post-operative NPWT of two- and four-fold, respectively. Investigations show that reduction in haematoma and seroma, accelerated wound healing and increased clearance of oedema are significant mechanisms of action. CONCLUSIONS: There is a rapidly emerging literature on the effect of NPWT on the closed incision. Initiated and confirmed first with a randomised controlled trial in orthopaedic trauma surgery, studies in abdominal, plastic and vascular surgery with high rates of complications have been reported recently. The evidence from single-use NPWT devices is accumulating. There are no large randomised studies yet in reconstructive joint replacement. Cite this article: Bone Joint Res 2013;2:276-84.The authors are members of an Expert Panel on incisional NPWT in orthopaedic surgery funded by Smith & Nephew

Historical review of arthroscopic surgery of the hip

\textbf{BACKGROUND & PURPOSE}: Increasing our appreciation of the historical foundations of hip arthroscopy offers greater insight and understanding of the field's current and future applications. This article offers a broad history of the progress of hip arthroscopy. $\textbf{METHODS}$: Hip arthroscopy's development from the early technologies of endoscopy to the present day is described through a review of the available literature. $\textbf{RESULTS}$: Endoscopic science begins with the Lichtleiter, developed by Phillip Bozzini (1779-1809) in 1806, but endoscopes were not applied to joints until 1912, as presented by Severin Nordentoft (1866-1922). The work of Kenji Takagi (1888-1963), especially, was instrumental in the arthroscope's development, allowing Michael Burman (1901-75) to perform the first recorded hip arthroscopy, detailed in a 1931 paper after extensive cadaveric research. Although World War II stalled further development, a renewed application of fibre optics following post-war innovations in glass manufacture heralded the modern arthroscope's invention. During the 1970s hip arthroscopy was first mobilized for diagnosis and exploration, leading to its later adoption for therapeutic surgical interventions. Modern hip arthroscopy has been facilitated by international research into optimum distraction, portals of entry, positioning of patients, and the technology of arthroscopic instruments. In 2008, the International Society for Hip Arthroscopy (ISHA) was founded to represent this international expert community. $\textbf{CONCLUSIONS}$: Technology, communication and evidence-based medicine have jointly facilitated the development of this young but promising corner of Orthopaedics