Transient elastohydrodynamic lubrication analysis of a novel metal-on-metal hip prosthesis with a non-spherical femoral bearing surface

Effective lubrication performance of metal-on-metal hip implants only requires optimum conformity within the main loaded area, while it is advantageous to increase the clearance in the equatorial region. Such a varying clearance can be achieved by using non-spherical bearing surfaces for either acetabular or femoral components. An elastohydrodynamic lubrication model of a novel metal-on-metal hip prosthesis using a non-spherical femoral bearing surface against a spherical cup was solved under loading and motion conditions specified by ISO standard. A full numerical methodology of considering the geometric variation in the rotating non-spherical head in elastohydrodynamic lubrication solution was presented, which is applicable to all non-spherical head designs. The lubrication performance of a hip prosthesis using a specific non-spherical femoral head, Alpharabola, was analysed and compared with those of spherical bearing surfaces and a non-spherical Alpharabola cup investigated in previous studies. The sensitivity of the lubrication performance to the anteversion angle of the Alpharabola head was also investigated. Results showed that the non-spherical head introduced a large squeeze-film action and also led to a large variation in clearance within the loaded area. With the same equatorial clearance, the lubrication performance of the metal-on-metal hip prosthesis using an Alpharabola head was better than that of the conventional spherical bearings but worse than that of the metal-on-metal hip prosthesis using an Alpharabola cup. The reduction in the lubrication performance caused by the initial anteversion angle of the non-spherical head was small, compared with the improvement resulted from the non-spherical geometry

Custom stems for femoral deformity in patients less than 40 years of age: 70 hips followed for an average of 14 years

Background and purpose Femoral deformity associated with osteoarthritis is a challenge for both the surgeon and the implant. Many of the patients with these deformities are young. Standard implants can be difficult to fit into these femurs. We prospectively evaluated the outcome of custom uncemented femoral stems in young patients

Increased Mortality in Metal-on-Metal versus Non-Metal-on-Metal Primary Total Hip Arthroplasty at 10 Years and Longer Follow-Up: A Systematic Review and Meta-Analysis

Analysis and Stochastic

Further evidence for executive dysfunction in subjects with RLS from a non-clinical sample

OBJECTIVE AND BACKGROUND: Previous studies exploring cognitive functioning in RLS have either relied on medication free subjects sampled within a clinical context or on subjects with RLS symptoms identified within population samples. However, in contrast to clinical samples, population studies so far have not excluded the use of antidepressants, hypnotics, or RLS relevant medication, and study subjects were exclusively older in age. We therefore report on cognitive functioning in predominantly middle-aged individuals with RLS symptoms sampled from the general population and free of mental disorders and of hypnotic, psychopharmacological, or RLS relevant medication. METHODS: Participants with RLS symptoms and individually matched controls were identified within the MARS control study, a non-clinical control group study of 550 participants between 18 and 75 years. Cognitive functioning was assessed with the Trail Making Test A and B and a computerized German version of the Wisconsin Card Sorting Test (WCST). Performance was compared between 41 participants with RLS and 133 controls, and between a subgroup of 10 participants with frequent RLS symptoms (≥ 2/week) and 36 matched controls. RESULTS: There was no difference in cognitive functioning for the complete group of participants with RLS and controls. However, participants with frequent RLS symptoms showed impaired performance in the WCST. CONCLUSION: The results of this study add to the evidence that executive functioning is impaired in individuals with frequent RLS

Wir stellen uns vor: ACTUM – Allergiezentrum der Technischen Universität München.

Das Allergiezentrum der TU München am Klinikum rechts der Isar wurde nach bereits langjähriger interdisziplinärer Zusammenarbeit am 8. April 2016 konstituiert und im März 2017 zertifiziert als Comprehensive Allergy Center. Die aktuelle Rezertifizierung erfolgte im November 2021. Gründungsmitglieder waren die Kliniken für Dermatologie und Allergologie, Hals-Nasen-Ohren-Heilkunde, Pneumologie, Gastroenterologie, Kinder- und Jugendmedizin, Ophthalmologie sowie als Rehabilitationseinrichtung die Fachklinik Gaißach. Ziele und Strukturen des ACTUM, die Schwerpunkte der einzelnen Bereiche sowie gemeinsame Projekte werden vorgestellt