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.

Effect of corticosteroids on human osteoclast formation and activity.

Abstract: Chronic corticosteroid treatment is known to induce bone loss and osteoporosis. Osteoclasts are specialised bone-resorbing cells that are formed from mononuclear phagocyte precursors that circulate in the monocyte fraction. In this study we have examined the effect of the synthetic glucocorticoid, dexamethasone, on human osteoclast formation and bone-resorbing activity. Human monocytes were cultured for up to 21 days on glass coverslips and dentine slices, with soluble receptor activator for nuclear factor kappaB ligand (RANKL; 30 ng/ml) and human macrophage-colony stimulating factor (M-CSF; 25 ng/ml) in the presence and absence of dexamethasone (10(-8) M). The addition of dexamethasone over a period of 7 and 14 days of culture of monocytes (during which cell proliferation and differentiation predominantly occurred) resulted in a marked increase in the formation of tartrate-resistant acid phosphatase-positive multinucleated cells and an increase in lacunar resorption. The addition of dexamethasone to monocyte cultures after 14 days (when resorptive activity of osteoclasts had commenced) reduced the extent of lacunar resorption compared with cultures to which no dexamethasone had been added. The addition of dexamethasone to osteoclasts isolated from giant cell tumours of bone significantly inhibited resorption pit formation. Our findings indicate that dexamethasone has a direct effect on osteoclast formation and activity, stimulating the proliferation and differentiation of human osteoclast precursors and inhibiting the bone-resorbing activity of mature osteoclasts.

Polyethylene wear in Oxford unicompartmental knee replacement: a retrieval study of 47 bearings.

Abstract: The Oxford Unicompartmental Knee replacement (UKR) was introduced as a design to reduce polyethylene wear. There has been one previous retrieval study involving this implant, which reported very low rates of wear in some specimens but abnormal patterns of wear in others. There has been no further investigation of these abnormal patterns. The bearings were retrieved from 47 patients who had received a medial Oxford UKR for anteromedial osteoarthritis of the knee. None had been studied previously. The mean time to revision was 8.4 years (sd 4.1), with 20 having been implanted for over ten years. The macroscopic pattern of polyethylene wear and the linear penetration were recorded for each bearing. The mean rate of linear penetration was 0.07 mm/year. The patterns of wear fell into three categories, each with a different rate of linear penetration; 1) no abnormal macroscopic wear and a normal articular surface, n = 16 (linear penetration rate = 0.01 mm/year); 2) abnormal macroscopic wear and normal articular surfaces with extra-articular impingement, n = 16 (linear penetration rate = 0.05 mm/year); 3) abnormal macroscopic wear and abnormal articular surfaces with intra-articular impingement +/− signs of non-congruous articulation, n = 15 (linear penetration rate = 0.12 mm/year). The differences in linear penetration rate were statistically significant (p These results show that very low rates of polyethylene wear are possible if the device functions normally. However, if the bearing displays suboptimal function (extra-articular, intra-articular impingement or incongruous articulation) the rates of wear increase significantly.

The prevalence of obstructive sleep apnoea and its association with aortic dilatation in Marfan’s syndrome

Abstract: BACKGROUND: Craniofacial abnormalities and increased pharyngeal collapsibility due to abnormal connective tissue suggest the possibility of an increased prevalence of obstructive sleep apnoea (OSA) in patients with Marfan's syndrome but the actual prevalence is uncertain. Aortic dilatation and dissection are life threatening manifestations of Marfan's syndrome and case reports have suggested a possible association with OSA but data from cohort studies are not available. METHODS: A sleep study was performed in 61 patients with Ghent criteria positive Marfan's syndrome (mean age 38.3 (SD 12.9) years; 37 females) and in 26 control subjects matched for age, gender, height and weight. OSA was defined using two conventional levels of apnoea-hypopnoea index (AHI), >5 and >15/h. In patients with Marfan's syndrome, aortic root diameter was measured by echocardiography. RESULTS: More patients with Marfan's syndrome than controls had OSA (AHI >5, 32.8% compared with 11.5%, mean difference +21.3%, 95% CI 4.2% to 38.3%, p = 0.04; AHI >15, 18.0% compared with 0%, mean difference +18.0%, 95% CI 8.4% to 27.7%, p = 0.02). AHI was correlated with aortic root diameter (r = 0.50, 95% CI 0.26 to 0.69, p = 0.0003), and mean aortic root diameter was significantly greater in patients with OSA (4.5 (SD 0.6) cm) compared with those without OSA (3.7 (0.6) cm) (mean difference 0.8 cm, 95% CI 0.4 to 1.2 cm, p<0.0001). CONCLUSIONS: In patients with Marfan's syndrome, the prevalence of OSA is considerably higher than in matched control subjects. OSA may be a risk factor for aortic root dilatation in Marfan's syndrome.

Correlation of Multidetector CT Findings with Splenic Arteriography and Surgery : Prospective Study in 392 Patients

Abstract: BACKGROUND: To determine the accuracy of contrast-enhanced multidetector CT (MDCT) in demonstrating splenic vascular injury based on results of splenic angiography and operation. STUDY DESIGN: This institutional review board-approved study included 392 hemodynamically stable blunt trauma patients whose admission MDCTs demonstrated splenic injury. Images were assessed for parenchymal injury grade, hemoperitoneum volume, and evidence of bleeding and nonbleeding splenic vascular injury. Splenic arteriography was performed for high splenic injury grade and splenic vascular injury. Medical records were reviewed to determine arteriographic interpretation, surgery indications and findings, outcomes, and demographics. Sensitivity, specificity, predictive values, and accuracy of MDCT in detecting vascular injury were calculated based on results of arteriography and operation. RESULTS: Splenic vascular injury was seen in 22% of patients (86 of 392) on MDCT. Presence of a vascular injury correlated with the CT-based parenchymal splenic injury grade (p < 0.0001). Active splenic bleeding was associated with subsequent clinical deterioration (p < 0.0001). Overall, MDCT had a sensitivity of 76% (76 of 100); specificity of 90% (95 of 106); negative and positive predictive values of 80% (95 of 119) and 87% (76 of 87), respectively; and accuracy of 83% (171 of 206) in detecting vascular injury compared with reference standards. The success rate of nonoperative management was 96%. CONCLUSIONS: MDCT provides valuable information to direct initial clinical management of patients with blunt splenic trauma by demonstrating both active bleeding and nonbleeding vascular injuries. Not all vascular injuries are detected on MDCT, and splenic angiography is still indicated for high-grade parenchymal injury.

An Intelligent Anthropomorphic Hand, with Automatic Grasp

Abstract: The current designs of commercial artificial hands have a low level of innovation. As feedback to the user is difficult to achieve reliably, most devices are simple in design and operation, and limited in functional range. If information on the state of the hand, the forces and any slippage that is occurring is fed back to a microcontroller then more than one degree of freedom can be controlled and a greater and more natural functional range is possible. This paper describes the development of such a device. It outlines the design requirements, the methods of detection of the signals and the training required to operate the hand.