The Effects of Different Femoral Component Materials on Bone and Implant Response in Total Knee Arthroplasty: A Finite Element Analysis

Due to the high stiffness of the biomaterials used in total knee arthroplasty, stress shielding can lead to decreased periprosthetic bone mineral density and bone resorption. As different materials and 3D-printed highly porous surfaces are available for knee femoral components from the industry nowadays, this study aimed to compare the effects of two same-design cruciate-retaining femoral components, made with CoCr and titanium alloy, respectively, on periprosthetic bone stresses through a finite element model of the implanted knee in order to evaluate the induced stress shielding. Moreover, the effect of the cementless highly porous surface of the titanium implant was analyzed in comparison to the cemented interface of the CoCr implant. The von Mises stresses were analyzed in different periprosthetic regions of interest of the femur with different configurations and knee flexion angles. The titanium component induced higher bone stresses in comparison with the CoCr component, mostly in the medial compartment at higher knee flexion angles; therefore, the CoCr component led to more stress shielding. The model was revealed to be effective in describing the effects of different femoral component materials on bone stress, highlighting how a cementless, highly porous titanium femoral component might lead to less stress shielding in comparison to a cemented CoCr implant with significant clinical relevance and reduced bone resorption after total knee arthroplasty.

Dietary inflammatory index as a potential determinant of a length of hospitalization among surgical patients treated for colorectal cancer

Background/objectives:

Inflammation is a central process responsible for health outcomes among surgical patients. Immunonutrition has been investigated as a promising modifying factor; however, inflammatory properties of habitual diet have not yet been investigated. The purpose of this study was to describe inflammatory properties of diet measured by the dietary inflammatory index (DII) among surgical patients treated for colorectal cancer and to link inflammatory properties of habitual diet with a duration of hospitalization.

Subjects/methods:

A follow-up study among colorectal cancer patients treated surgically was performed in Krakow, Poland. In total, 689 patients were recruited for the study. Habitual diet was assessed using a standardized semiquantitative food frequency questionnaire. Overall, 23 dietary items (including macro-and micronutrients) were used to calculate individuals' DII. Gender, age, marital status, body mass index, smoking status, lifetime physical activity, taking vitamin supplements, number of chronic diseases, cancer site, Duke's staging and surgery type were considered as potential covariates.

Results:

Participants were aged 58 years, with the average hospitalization time of 11 days. Higher DII (meaning diet with higher anti-inflammatory properties) was negatively associated with the duration of hospitalization (univariable linear regression: b=−0.59; P=0.005). Multivariable logistic regression has shown the decrease of the risk of longer stays (>7 days) among patients with the DII >−4.25, but only among younger (⩽60 years) patients, irrespective of Duke's staging.

Conclusions:

The DII might be used as a potential predictor of longer hospitalization among colorectal cancer patients treated surgically. The study provides evidence for the role of dietary-related low-grade inflammation among surgical patients.

Inclusive K(S);(0)K(S);(0) resonance production in ep collisions at HERA

Inclusive K_{S};{0}K_{S};{0} production in ep collisions at the DESY ep collider HERA was studied with the ZEUS detector using an integrated luminosity of 0.5 fb;{-1}. Enhancements in the mass spectrum were observed and are attributed to the production of f_{2}(1270)/a_{2};{0}(1320), f_{2};{'}(1525) and f_{0}(1710). Masses and widths were obtained using a fit which takes into account theoretical predictions based on SU(3) symmetry arguments, and are consistent with the Particle Data Group values. The f_{0}(1710) state, which has a mass consistent with a glueball candidate, was observed with a statistical significance of 5 standard deviations. However, if this state is the same as that seen in gammagamma-->K_{S};{0}K_{S};{0}, it is unlikely to be a pure glueball state.

Case–control study of lifetime occupational and recreational physical activity and risks of colon and rectal cancer

Important aspects of the inverse relation between physical activity and colon cancer risk are still under discussion. In 2000-2003, 239 incident cases of colorectal cancer confirmed by histopathology and 239 hospital-based controls, matched by age and gender, were enrolled. In standardized interviews, data on occupational and recreational physical activity for ages 20, 30, 40, 50 and 60 years were collected from 98 colon cancer cases, 141 rectal cancer cases, and from 193 controls. Besides lifestyle and sociodemographic characteristics, a detailed food frequency questionnaire was assessed. In multivariate logistic regression for colon cancer, significant risk reductions for the highest quartile of total physical activity were found for almost all ages. For lifetime mean physical activity, the multivariate odds ratio for the highest quartile was 0.37 [95% confidence interval (CI) 0.17, 0.83]. For lifelong constantly high-exercisers compared with lifelong non-exercisers an odds ratio of 0.26 (95% CI 0.08, 0.84) was estimated. For rectal cancer, no consistent association with physical activity was found. No confounding effects were observed but the authors found effect modification with total energy intake. These data support an inverse association of colon cancer risk and physical activity which is most expressed if activity is kept up throughout life.