55 research outputs found
Preventing tibial and talar component contact during implantation of a total ankle replacement.
The influence of malalignment and ageing following sterilisation by gamma irradiation in an inert atmosphere on the wear of ultra-high-molecular-weight polyethylene in patellofemoral replacements
Complications of patellofemoral arthroplasty often occur soon after implantation and, as well as other factors, can be
due to the design of the implant or its surgical positioning. A number of studies have previously considered the wear of
ultra-high-molecular-weight polyethylene patellae following suboptimal implantation; however, studies have primarily
been carried out under a limited number of degrees of freedom. The aim of this study was to develop a protocol to
assess the wear of patellae under a malaligned condition in a six-axis patellofemoral joint simulator. The malalignment
protocol hindered the tracking of the patella centrally in the trochlear groove and imparted a constant 5 external rotation
(tilt) on the patella button. Following 3 million cycles of wear simulation, this condition had no influence on the wear
of ultra-high-molecular-weight polyethylene patellae aged for 4 years compared to well-positioned non-aged implants
(p . 0.05). However, under the malaligned condition, ultra-high-molecular-weight polyethylene patellae aged 8–10 years
after unpacking (following sterilisation by gamma irradiation in an inert atmosphere) and worn ultra-high-molecularweight
polyethylene components also aged 4 years after unpacking (following the same sterilisation process) exhibited a
high rate of wear. Fatigue failure due to elevated contact stress led to delamination of the ultra-high-molecular-weight
polyethylene and in some cases complete failure of the patellae. The results suggest that suboptimal tracking of the
patella in the trochlear groove and tilt of the patella button could have a significant effect on the wear of ultra-high-molecular-weight
polyethylene and could lead to implant failure
Estimating an individual's probability of revision surgery after knee replacement : a comparison of modeling approaches using a national dataset
Tools that provide personalized risk prediction of the outcomes after surgical procedures help patients to make preference-based decisions amongst the available treatment options. However, it is unclear which modeling approach provides the most accurate risk estimation. We constructed and compared several parametric and non-parametric models for predicting prosthesis survivorship after knee replacement surgery for osteoarthritis. We used 430,455 patient-procedure episodes between April 2003 and September 2015 from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. The flexible parametric survival and random survival forest models most accurately captured the observed probability of remaining event-free. The concordance index for the flexible parametric model was the highest (0.705; 95% confidence interval: 0.702, 0.707) for total knee replacement, 0.639 (95% confidence interval: 0.634, 0.643) for unicondylar knee replacement and 0.589 (95% confidence interval: 0.586, 0.592) for patellofemoral replacement. The observed-to-predicted ratios for both the flexible parametric and the random survival forest approaches indicated that models tended to underestimate the risks for most risk groups. Our results show that the flexible parametric model has a better overall performance compared to other tested parametric methods, and better discrimination compared to the random survival forest approach
What does standard rehabilitation practice after total hip replacement in the UK entail? results of a mixed methods study
Mixed methods evaluation of the Getting it Right First Time programme - improvements to NHS orthopaedic care in England: study protocol
What is the evidence base to guide surgical treatment of infected hip prostheses? systematic review of longitudinal studies in unselected patients
Local anaesthetic infiltration for peri-operative pain control in total hip and knee replacement: systematic review and meta-analyses of short- and long-term effectiveness
Clinical- and cost-effectiveness of the STAR care pathway compared to usual care for patients with chronic pain after total knee replacement: study protocol for a UK randomised controlled trial.
Approximately 20% of patients experience chronic pain after total knee replacement. There is little evidence for effective interventions for the management of this pain, and current healthcare provision is patchy and inconsistent. Given the complexity of this condition, multimodal and individualised interventions matched to pain characteristics are needed. We have undertaken a comprehensive programme of work to develop a care pathway for patients with chronic pain after total knee replacement. This protocol describes the design of a randomised controlled trial to evaluate the clinical- and cost-effectiveness of a complex intervention care pathway compared with usual care.This article is freely available via Open Access. Click on the Additional Link above to access the full-text via the publisher's site
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