A new anterolateral surgical approach for total hip replacement.

PURPOSE: the purpose of the present paper is to present the short-term results of a "detachment-free" (DF) anterolateral approach for primary total hip replacement (THR) performed in a large series of patients. METHODS: two hundred patients submitted to primary THR were retrospectively reviewed for the present study. In all cases, the surgery was performed using a minimally invasive DF anterolateral approach, which entails no disconnection of tendons and no muscle damage. The study population consisted of 96 men (48%) and 104 women (52%), with an average age of 69.4 years (range 38-75). Clinical and radiographic follow-up was performed after 12 months. RESULTS: the clinical results, evaluated using the Harris Hip Score, were excellent in 95% of the cases and good in 5%; no cases had fair or poor results. X-rays taken at 3, 6 and 12 months after surgery did not show heterotopic ossification, mobilization of the prosthetic components, or hip dislocation. No infections, deep vein thrombosis, or failure of the gluteal muscles were reported. CONCLUSIONS: the DF anterolateral approach for THR proved safe and provided effective results at short-term follow-up. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Temporal patterning of the potential induced by localized corrosion of iron passivity in acid media. Growth and breakdown of the oxide film described in terms of a point defect model.

This work analyses the nature of temporal patterning of the anodic potential induced by chlorides during polarization of iron under current-controlled conditions in acid solutions. It is shown that potential oscillations emerged as a result of the local chloride attack of a thin oxide layer, which covers the iron surface in its passive state. The mechanism by which both the local oxide breakdown and the subsequent localized active dissolution (pitting) occur is explained by considering a point defect model (PDM) developed to describe the oxide growth and breakdown. According to the PDM, chlorides occupy oxygen vacancies resulting in the inhibition of oxide growth and autocatalytic generation of cation vacancies that destabilize the oxide layer. Simultaneous transformation of the outer surface of the inner oxide layer to non-adherent ferrous chloride or oxo-chloride species leads to a further thinning of the oxide layer and its lifting-on from the iron surface. The process repeats again yielding sustained oscillations of the anodic potential. Analysis of the oscillatory response obtained under current-controlled conditions as a function of either the current or the time allows the suggestion of a set of alternate diagnostic criteria, which might be used to characterize localized corrosion of iron in acid solutions.