Femoral revision knee Arthroplasty with Metaphyseal sleeves: the use of a stem is not mandatory of a structural point of view

Purpose Metaphyseal sleeves are an option for patients with severe metaphyseal bony defects requiring TKA revision. Although sleeves are usually used with stems, little is known about the exact contribution/need of the stem for the initial sleeve-bone interface stability, particularly in the femur, if the intramedullary canal is deformed or bowed. It is hypothesised that diaphyseal-stem addition increases the sleeve-femur interface stability and the strain-shielding effect on the metaphyseal femur relatively to the stemless condition. Material and methods Synthetic-femur was used to measure cortex strain behaviour and implant cortex micromotions for three techniques: only femoral-component, stemless-sleeve and stemmed-sleeve. Paired t-tests were performed to evaluate the statistical significance of the difference between mean principal strains and implant-cortex micromotions. Finite-element models were developed to assess the cancellous-bone strain behaviour and sleeve-bone interface micromotions; these models were validated against the measurements. Results Cortex strains are reduced significantly (p<0.05) in 83% of strain gauges on stemmed-sleeve, which compares with 33% in stemless condition. Both techniques presented a cancellous bone strain reduction of 50% at the distal region and an increase of nearly four times at the sleeve proximal region relative to the model only with the femoral component. Both techniques presented sleeve-bone micromotions amplitude below 50-150μm, suitable for bone ingrowth. Conclusions The use of a supplemental diaphyseal-stem potentiates the risk of cortex bone resorption compared with the stemless-sleeve condition; however, the stem is not vital for increasing the initial sleeve-bone stability and has a minor effect on the cancellous-bone strain behaviour. Of a purely structural point view, appears that the use of a diaphyseal-femoral-stem with the metaphyseal sleeve is not mandatory in the revision TKA which is particularly relevant in cases where the use of stems is impracticable.publishe

Thirty-day mortality after hip fractures: has anything changed?

Bone density insufficiency is the main cause for significant musculoskeletal trauma in the elderly population following low-energy falls. Hip fractures, in particular, represent an important public health concern taking into account the complicated needs of the patients due to their medical comorbidities as well as their rehabilitation and social demands. The annual cost for the care of these patients is estimated at around 2 billion pounds (£) in the UK and is ever growing. An increased early and late mortality rate is also recognised in these injuries together with significant adversities for the patients. Lately, in order to improve the outcomes of this special cohort of patients, fast-track care pathways and government initiatives have been implemented. It appears that these measures have contributed in a steady year-by-year reduction of the 30-day mortality rates. Whether we have currently reached a plateau or whether an ongoing reduction in mortality rates will continue to be observed is yet to be seen

Impact of comorbidity on the short- and medium-term risk of revision in total hip and knee arthroplasty

Background: The impact of comorbidity on the risk of revision in patients undergoing Total Knee arthroplasty (TKA) and Total Hip Arthroplasty (THA) is not currently well known. The aim of this study was to analyze the impact of comorbidity on the risk of revision in TKA and THA. Methods: Patients recorded in the Catalan Arthroplasty Register (RACat) between 01/01/2005 and 31/12/2016 undergoing TKA (n = 49,701) and THA (n = 17,923) caused by osteoarthritis were included. As main explanatory factors, comorbidity burden was assessed by the Elixhauser index, categorized, and specific comorbidities from the index were taken into account. Descriptive analyses for comorbidity burden and specific conditions were done. Additionally, incidence at 1 and 5 years' follow-up was calculated, and adjusted Competing Risks models were fitted. Results: A higher incidence of revision was observed when the number of comorbidities was high, both at 1 and 5 years for THA, but only at 1 year for TKA. Of the specific conditions, only obesity was related to the incidence of revision at 1 year in both joints, and at 5 years in TKA. The risk of revision was related to deficiency anemia and liver diseases in TKA, while in THA, it was related to peripheral vascular disorders, metastatic cancer and psychoses. Conclusions: Different conditions, depending on the joint, might be related to higher revision rates. This information could be relevant for clinical decision-making, patient-specific information and improving the results of both TKA and THA.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.The present study was funded by CIBER Epidemiology and Public Health (CIBERESP) as part of the aid for short internships granted to Jorge Arias-de la Torre in 2017 and 2018.published version, accepted versio