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Identification of in vivo passive biomechanical properties of healthy human myocardium from regular clinical data is essential for subject-specific modelling of left ventricle (LV). In this work, myocardium was defined by Holzapfel-Ogden constitutive law. Therefore, the objectives of the study were (a) to estimate the ranges of the constitutive parameters for healthy human myocardium using non-invasive routine clinical data, and (b) to investigate the effect of geometry, LV end-diastolic pressure (EDP) and fibre orientations on estimated values. In order to avoid invasive measurements and additional scans, LV cavity volume, measured from routine MRI, and empirical pressure-normalised-volume relation (Klotz-curve) were used as clinical data. Finite element modelling, response surface method and genetic algorithm were used to inversely estimate the constitutive parameters. Due to the ill-posed nature of the inverse optimisation problem, the myocardial properties was extracted by identifying the ranges of the parameters, instead of finding unique values. Additional sensitivity studies were carried out to identify the effect of LV EDP, fibre orientation and geometry on estimated parameters. Although uniqueness of the solution cannot be achieved, the normal ranges of the parameters produced similar mechanical responses within the physiological ranges. These information could be used in future computational studies for designing heart failure treatments. Graphical abstract

In total hip arthroplasty, determining the impingement free range of motion requirement is a complex task. This is because in the native hip, motion is restricted by both impingement as well as soft tissue restraint. The aim of this study is to determine a range of motion benchmark which can identify motions which are at risk from impingement and those which are constrained due to soft tissue. Two experimental methodologies were used to determine motions which were limited by impingement and those motions which were limited by both impingement and soft tissue restraint. By comparing these two experimental results, motions which were limited by impingement were able to be separated from those motions which were limited by soft tissue restraint. The results show motions in extension as well as flexion combined with adduction are limited by soft tissue restraint. Motions in flexion, flexion combined with abduction and adduction are at risk from osseous impingement. Consequently, these motions represent where the maximum likely damage will occur in femoroacetabular impingement or at most risk of prosthetic impingement in total hip arthroplasty.Electronic supplementary materialThe online version of this article (doi:10.1007/s11517-012-1016-3) contains supplementary material, which is available to authorized users.

The increasing interest towards intelligent systems has led to a demand for the development of zero-defect strategies, with a paradigm shift from off-line and dedicated to inline metrology with integrated robotic systems. However, a major barrier preventing the systematic uptake of in-line metrology is the lack of evaluation of system capability in terms of accuracy, repeatability and measurement time, when compared to the well-established coordinate measuring machine (CMM). In this study, a robotic Laser Radar (LR) solution is assessed in the context of automotive dimensional inspection of Body-In-White (BIW) applications. The objective is both to understand the effect of robot re-positioning error on measurement accuracy and repeatability and to compare measurement results against a CMM. Eighty-one surface points, six edge points, twenty-five holes and sixteen slots were selected from an industry standard measurement plan. Whilst LR exhibits a lower measurement accuracy than twin-column CMM, its repeatability is well within the specification limits for body shell quality inspection. Therefore, as a real-time in-line metrology tool, it is a genuine prospect to exploit. This research makes a significant contribution toward in-line metrology for dimensional inspection, for automotive application, for rapid detection and for correction of assembly defects in real time, with subsequent reduction of scrap and number of repairs/re-works.

ARTICLE IN PRESS

Range of motion of the hip joint is a major contributor to dislocation post total hip replacement.Impingement is often treated as a surrogate for dislocation and occurs -prosthetically -when the neck of the femoral component contacts with the rim of the pelvic acetabular cup. This impingement is caused by movement of the leg during activities of daily living. This article analyses hip joint range of motion and its implication for impingement.A systematic literature review was undertaken with the purpose of establishing a range of motion benchmark for total hip replacement. This paper proposes a method by which a three-dimensional range of motion boundary established from the literature can be presented. The nominal boundary is also validated experimentally using a number of configurations of a neutral hip joint coordinate frame.

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The femoral footprint of the anterior cruciate ligament (ACL) is a much-studied anatomic structure, predominantly due to its importance during ACL reconstruction surgery. A new technique utilising high-resolution micro-computed tomography (micro-CT) is described, allowing detailed three-dimensional (3D) quantitative analysis of this structure. Seven cadaveric knees were scanned using micro-CT, yielding 3D data with a reconstructed voxel size of 60 μm. A novel method of 3D surface extraction was developed and validated, facilitating both qualitative observation of surface details and quantitative topographic assessment using colour-coded relief maps. Images were displayed on an immersive 3D visualisation wall, and ten experienced ACL clinicians were surveyed as to the presence and morphology of osseous landmarks, providing qualitative assessment of whether such features can be reliably identified for navigation during surgery. Both quantitative analysis and qualitative assessment of the footprints in this study showed significant variability in the presence and morphology of osseous landmarks, with the lateral intercondylar ridge being objectively present in four out of seven relief maps, although reportedly seen in six out of seven cases in the qualitative study, suggesting an element of subjectivity and interpretation. This is the first study to utilise micro-CT in the study of ACL anatomy.