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.

Informed Conditioning on Clinical Covariates Increases Power in Case-Control Association Studies

Abstract: Genetic case-control association studies often include data on clinical covariates, such as body mass index (BMI), smoking status, or age, that may modify the underlying genetic risk of case or control samples. For example, in type 2 diabetes, odds ratios for established variants estimated from low–BMI cases are larger than those estimated from high–BMI cases. An unanswered question is how to use this information to maximize statistical power in case-control studies that ascertain individuals on the basis of phenotype (case-control ascertainment) or phenotype and clinical covariates (case-controlcovariate ascertainment). While current approaches improve power in studies with random ascertainment, they often lose power under case-control ascertainment and fail to capture available power increases under case-control-covariate ascertainment. We show that an informed conditioning approach, based on the liability threshold model with parameters informed by external epidemiological information, fully accounts for disease prevalence and non-random ascertainment of phenotype as well as covariates and provides a substantial increase in power while maintaining a properly controlled falsepositive rate. Our method outperforms standard case-control association tests with or without covariates, tests of gene x covariate interaction, and previously proposed tests for dealing with covariates in ascertained data, with especially large improvements in the case of case-control-covariate ascertainment. We investigate empirical case-control studies of type 2 diabetes, prostate cancer, lung cancer, breast cancer, rheumatoid arthritis, age-related macular degeneration, and end-stage kidney disease over a total of 89,726 samples. In these datasets, informed conditioning outperforms logistic regression for 115 of the 157 known associated variants investigated (P-value=1610 29 ). The improvement varied across diseases with a 16% median increase in x 2 test statistics and a commensurate increase in power. This suggests that applying our method to

Dislocation of the bearing of the Oxford lateral unicompartmental arthroplasty: A RADIOLOGICAL ASSESSMENT

Abstract: When the Oxford unicompartmental meniscal bearing arthroplasty is used in the lateral compartment of the knee, 10% of the bearings dislocate. A radiological review was carried out to establish if dislocation was related to surgical technique. The postoperative radiographs of 46 lateral unicompartmental arthroplasties were analysed. Five variables which related to the position and alignment of the components were measured. Dislocations occurred in six knees. Only one of the five variables, the proximal tibial varus angle, had a statistically significant relationship to dislocation. This variable quantifies the height of the lateral joint line. The mean proximal tibial varus angle for knees the bearings of which had dislocated was 9 degrees and for those which had not it was 5 degrees. In both groups it was greater than would be expected in the normal knee (3 degrees). Our study suggests that a high proximal tibial varus angle is associated with dislocation. The surgical technique should be modified to account for this, with care being taken to avoid damage to or overdistraction of the lateral soft tissues.

Evidence-Based Indications for Mobile-Bearing Unicompartmental Knee Arthroplasty in a Consecutive Cohort of Thousand Knees

Abstract: Background The indications for unicompartmental knee arthroplasty remain controversial. Previously recommended contraindications include the following: age under 60 years, weight 180 lb (82 kg) or over, patients undertaking heavy labor, chondrocalcinosis, and exposed bone in the patellofemoral joint. This study explores whether these contraindications are valid in mobile-bearing unicompartmental knee arthroplasty. Methods Using a prospective series of 1000 consecutive medial unicompartmental knee arthroplasties in which the reported contraindications were not applied, the functional outcome and survival in patients with or without contraindications were compared. Results Of the 1000 consecutive unicompartmental knee arthroplasties (818 patients), 68% (678 knees) would be considered contraindicated based on published contraindications. At a mean follow-up of 10 years (5-17), there was no difference in American Knee Society (AKS) Objective Scores ( P = .05) or Oxford Knee Score ( P = .08) between groups. However, knees with contraindications had significantly ( P = .02) fewer poor outcomes and significantly better AKS Functional Scores ( P P P = .33) was observed. The 3% of unicompartmental knee arthroplasties performed in young men (age P P = .01), and Tegner Activity Score ( P P = .54) at 10 years or implant survival at 15 years ( P = .75) was seen. Conclusion This large case series provides evidence that patients with the previously reported contraindications do as well as, or even better than, those without contraindications. Therefore these contraindications should not apply to mobile-bearing unicompartmental knee arthroplasty.

MRI of soft tissue masses of the hand and wrist

Abstract: The vast majority of soft tissue mass lesions of the wrist and hand are benign [1, 2]. In practice, the most common lesions encountered are ganglia. The most frequently seen solid masses include giant cell tumours of tendon sheath (GCTTS), lipomas, Dupuytren’s contractures, nerve sheath tumours, glomus tumours, haemangioma/vascular malformations and synovial pathology. In general, MRI is unable to differentiate between benignity and malignancy, but in many circumstances a specific diagnosis may be achieved by taking into account the location of the lesion within the hand or wrist and its signal characteristics [2–4]. Plain films and CT may detect calcification and allow assessment of adjacent bony structures but, unlike MRI, do not offer much in the way of tissue characterization. Ultrasound has an extremely useful role in localizing lesions and determining if the lesion is cystic or solid [5, 6], but further tissue characterization is limited. This pictorial review covers the MRI appearances of the most commonly encountered soft tissue masses of the wrist and hand, and describes the main features, specifically the signal characteristics and location, that help differentiate them.