Nuffield Orthopaedic Centre

About: Nuffield Orthopaedic Centre is a healthcare organization based out in Oxford, United Kingdom. It is known for research contribution in the topics: Population & Arthroplasty. The organization has 2082 authors who have published 2920 publications receiving 145718 citations.

Osteoclasts are capable of particle phagocytosis and bone resorption.

Abstract: Osteoclasts are multinucleated cells specialized for the function of lacunar bone resorption. Although they are known to be capable of phagocytosis of inert particles, it is not known whether this abolishes their ability to respond to hormones or to form resorption lacunae. Human and rat osteoclasts were isolated from giant cell tumours of bone and rat long bones, respectively, and cultured on coverslips and cortical bone slices, both in the presence and in the absence of particles of latex (1 μm diameter) and polymethylmethacrylate (PMMA) (<50 μm). By light microscopy, it was evident that osteoclasts which had phagocytosed both latex and PMMA particles remained responsive to calcitonin. Osteoclast phagocytosis of particles was also evident on scanning electron microscopy, where it could also be seen that these cells were associated with the formation of resorption lacunae. These findings underline the fact that the osteoclast is a true member of the mononuclear phagocyte system and that phagocytosis does not abrogate either its hormonal response to calcitonin or its highly specialized function of bone resorption. That osteoclasts which have phagocytosed biomaterial particles such as PMMA are still able to carry out lacunar bone resorption is of interest in clinical conditions such as aseptic loosening, where a heavy foreign body particle load is often associated with extensive bone resorption. © 1997 John Wiley & Sons, Ltd.

Specifying the target difference in the primary outcome for a randomised controlled trial: guidance for researchers.

Abstract: Central to the design of a randomised controlled trial is the calculation of the number of participants needed This is typically achieved by specifying a target difference and calculating the corresponding sample size, which provides reassurance that the trial will have the required statistical power (at the planned statistical significance level) to identify whether a difference of a particular magnitude exists Beyond pure statistical or scientific concerns, it is ethically imperative that an appropriate number of participants should be recruited Despite the critical role of the target difference for the primary outcome in the design of randomised controlled trials, its determination has received surprisingly little attention This article provides guidance on the specification of the target difference for the primary outcome in a sample size calculation for a two parallel group randomised controlled trial with a superiority question This work was part of the DELTA (Difference ELicitation in TriAls) project Draft guidance was developed by the project steering and advisory groups utilising the results of the systematic review and surveys Findings were circulated and presented to members of the combined group at a face-to-face meeting, along with a proposed outline of the guidance document structure, containing recommendations and reporting items for a trial protocol and report The guidance and was subsequently drafted and circulated for further comment before finalisation Guidance on specification of a target difference in the primary outcome for a two group parallel randomised controlled trial was produced Additionally, a list of reporting items for protocols and trial reports was generated Specification of the target difference for the primary outcome is a key component of a randomized controlled trial sample size calculation There is a need for better justification of the target difference and reporting of its specification

The proposed role of ultrasound in the management of giant cell arteritis in routine clinical practice

Abstract: Objective To develop and explore a protocol for using colour duplex sonography (CDS) in the routine care of GCA. Methods We tested CDS of temporal arteries and axillary arteries (AXs) on consecutive patients with suspected or established GCA, between July 2014 and September 2016. Results We assessed 293 patients [age 72 (10), female/male 196/97], of whom 118 had clinically confirmed GCA. Seventy-three percent of patients had already received high-dose glucocorticoids (GCs) for 17 (33) days. Among new referrals with <7 days of GC treatment (n = 55), the sensitivity of CDS was 63.3% (95% CI: 44%, 80%), specificity 100% (95% CI: 83%, 100%), positive predictive value 100% and negative predictive value 64.5% (95% CI: 53%, 74%). Sensitivity rose to 81.8% in patients with jaw claudication and high inflammatory markers. During the observation period, the rate of temporal artery biopsies decreased from 72 (42%) to 36 (25%) (P = 0.002). CDS was positive in 21% of 89 follow-up scans in asymptomatic individuals, compared with 37% in patients experiencing clinical flares. Over time, the number of halos reduced; only new or flaring patients showed a halo in four or more sites. The diameter of axillary halos reduced from referral [1.6 (0.4) mm] to follow-up [1.4 (0.2) mm, P = 0.01] or flares [1.4 (0.2) mm, P = 0.02]. Conclusion CDS provides high positive predictive value for diagnosing GCA and allows for a significant reduction in temporal artery biopsies. We explored the role of CDS in detecting flares and demonstrated a relationship to the extent of the distribution of halos, but not to their size.

In vivo measurement of tissue metabolism in tendons of the rotator cuff: implications for surgical management.

Abstract: We have undertaken an in vivo assessment of the tissue metabolism and cellular activity in torn tendons of the rotator cuff Cellular oxygen consumption was measured in 13 patients undergoing mini-open repair of small, medium, large and massive full-thickness tears Measurements were also taken from three control patients who were undergoing open stabilisation of the shoulder with grossly normal tendons The level of oxygen and nitrous oxide was measured amperometrically using silver needle microelectrodes at the apex of the tear and 15 cm from its edge With nitrous oxide indicating the degree of perfusion, oxygen consumption was calculated at each location to reflect cellular activity All of the torn tendons had lower levels of cellular activity than the control group This activity was lower still in the tissue nearest to the edge of the tear with the larger tears showing the lowest activity This indicated reduced levels of tissue metabolism and infers a reduction in tendon viability Our findings suggest that surgical repair of torn tendons of the rotator-cuff should include the more proximal, viable tissue, and may help to explain the high rate of re-rupture seen in larger tears