Factors affecting aseptic loosening of 4750 total hip arthroplasties: multivariate survival analysis

Background  

Total hip arthroplasty is a successful surgery, that fails at a rate of approximately 10% at ten years from surgery. Causes for failure are mainly aseptic loosening of one or both components partially due to wear of articular surfaces and partially to design. The present analysis aimed to identify risk factors and quantify their effects on aseptic failure.     

Effects of the sterilisation method on the wear of UHMWPE acetabular cups tested in a hip joint simulator

Ultra-high molecular-weight-polyethylene is the most commonly used bearing material in total joint replacement. Wear of polyethylene is a Serious Clinical problem that limits the longevity of orthopaedic implants. Information on degradative changes in the material properties and on the methods used for the sterilisation of polyethylene may help in the selection process of orthopaedic implants with the best wear resistance. This study was performed to investigate the effects of the sterilisation method (gamma irradiation and ethylene oxide treatment) on the wear and on the changes in physical properties of polyethylene acetabular cups. At this purpose, gamma-sterilised and ethylene oxide (EtO)-sterilised acetabular cups were tested against CoCr femoral heads in a hip joint simulator run for 5 million cycles in bovine calf serum. The crystallinity of the cups was evaluated by micro-Raman spectroscopy as a function of the inner surface position. The partial least square calibration was used to correlate the Raman spectra with the crystallinity of the polymer measured by differential scanning calorimetry. The analysis performed on soak control acetabular cups demonstrated that the gamma-sterilised cups are significantly more crystalline than the EtO-sterilised ones. The mean crystallinity values obtained for the gamma-sterilised and EtO-sterilised soak control cups were 65.0% and 63.4%, respectively. Weight loss measurements revealed that the gamma-sterilised acetabular cups exhibited a lower wear rate than that by EtO-sterilised. Thc Raman results obtained on gamma-sterilised and EtO-sterilised acetabular cups showed that the changes in surface crystallinity were mainly caused by irradiation rather than by the mechanical friction during the in vitro tests.     

Synergistic potential of 1α,25-dihydroxyvitamin D3 and calcium–aluminate–chitosan scaffolds with dental pulp cells

Clinical Oral Investigations - This study aimed to develop a porous chitosan–calcium–aluminate scaffold (CH-AlCa) in combination with a bioactive dosage of 1α,25-dihydroxyvitamin...     

Evaluation of placebo use in migraine without aura, migraine with aura and episodic tension-type headache acute attacks

This study presents an evaluation of placebo response in the acute treatment of migraine with or without aura and episodic tension type headache. We studied patients admitted between March 1st,1997 and November 31st,1999 in two Emergency Room Units. Three groups had been defined, each one with 30 participants: migraine without aura (MWOA), migraine with aura (MWA) and episodic tension-type headache (ETTH). Patients were participating of a randomized study to evaluate efficacy of 4 different drugs; those randomized to receive placebo were included. We evaluated pain and associated symptoms. After one hour of placebo administration, 50% of MWOA patients, 23.3% of MWA and 26.7% of ETTH had presented pain relief. The mean of this relief, evaluated by the numerical pain scale, was 41.6%, 23.1% and 36%, respectively. Use of placebo is essential in evaluating the therapeutic role of drugs used in the treatment of acute headache.     

Cerebral vasospasm and headache during sexual intercourse and masturbatory orgasms

BACKGROUND: The pathophysiology of the explosive type of headache associated with sexual activity is not completely understood. Five reported cases of patients with thunderclap headache, precipitated by sexual activity, in association with concomitant cerebral arterial narrowing, were found in the literature. METHODS: A 44-year-old woman with both coital and masturbatory headaches during orgasm associated with segmental reversible cerebral artery vasospasm was investigated. Cerebral anatomy and eventual spasm was documented by magnetic resonance imaging or digital angiography before, during, and after resolution of the orgasmic headache-vasospasm clinical manifestation. CONCLUSION: Findings of cerebral arterial narrowing, presented by some patients shortly after orgasmic headache attacks, support the hypothesis that segmental vasospasm may exert a role in the pathogenesis of this uncommon type of headache. The literature is reviewed, and possible mechanisms underlying the development of orgasmic headache are discussed.     

Evaluation of pH and Calcium Ion Release of Root-end Filling Materials Containing Calcium Hydroxide or Mineral Trioxide Aggregate

IntroductionTo evaluate calcium ion release and pH of Sealer 26 (S26) (Dentsply, Rio de Janeiro, RJ, Brazil), white mineral trioxide aggregate (MTA), Endo CPM Sealer (CPM1) (EGEO SRL Bajo licencia MTM Argentina SA, Buenos Aires, Argentina), Endo CPM Sealer in a thicker consistency (CPM 2), and zinc oxide and eugenol cement (ZOE).MethodsMaterial samples (n = 10) were placed in polyethylene tubes and immersed in 10 mL of distilled water. After 3, 6, 12, 24, and 48 hours and 7, 14, and 28 days, the water pH was determined with a pH meter, and calcium release was assessed by atomic absorption spectrophotometry. An empty tube was used as the control group.ResultsThe control group presented a pH value of 6.9 at all studied periods and did not show the presence of calcium ion. S26 presented greater hydroxyl ion release up to 12 hours (p < 0.05). From 24 hours until 28 days, S26, MTA, CPM1, and CPM2 had similar results. In all periods, ZOE presented the lowest hydroxyl ion release. CPM1, followed by CPM2, released the most calcium ions until 24 hours (p < 0.05). Between 48 hours and 7 days, CPM1 and CPM2 had the highest release. A greater calcium ion release was observed for CPM2, followed by CPM1 at 14 days and for S26, CPM1, and CPM2 at 28 days. ZOE released the least calcium ions in all periods.ConclusionSealer 26, MTA, and Endo CPM sealer at normal or thicker consistency release hydroxyl and calcium ions. Endo CPM sealer may be an alternative as root-end filling material.     

Short Stems Versus Conventional Stems in Cementless Total Hip Arthroplasty: A Long-Term Registry Study

Background

Short stems in total hip arthroplasty (THA) have recently gained increasing popularity, allowing mini-invasive exposures and bone-sparing approaches. However, long-term studies and recommendations for the routine use are not available. The aim of this report was to compare the survival rates and the reasons for revision of short stems versus conventional stems in cementless THAs, in a registry-based population.