Search

Porous tantalum has been extensively used in orthopaedic surgery, including uncemented total knee arthroplasty (TKA). Favourable results were reported with earlier monobloc tibial components and the design evolved to modular implants. We aimed to analyse possible causes for extensive medial tibia bone loss, resulting in modular porous tantalum tibia baseplate fracture after primary TKA. Retrieved tissue samples were scanned with 3 MeV focused proton beam for Proton-Induced X-ray Emission (micro-PIXE) elemental analysis. Fractographic and microstructural analysis were performed by stereomicroscopy. A full 3D finite-element model was made for numerical analysis of stress–strain conditions of the tibial baseplate. Histological examination of tissue underneath the broken part of the tibial baseplate revealed dark-stained metal debris, which was confirmed by micro-PIXE to consist of tantalum and titanium. Fractographic analysis and tensile testing showed that the failure of the tibial baseplate fulfilled the criteria of a typical fatigue fracture. Microstructural analysis of the contact surface revealed signs of bone ingrowth in 22.5% of the surface only and was even less pronounced in the medial half of the tibial baseplate. Further studies are needed to confirm the responsibility of metal debris for an increased bone absorption leading to catastrophic tibial tray failure.

The olive (Olea europaea L.) leaves, as central part of the olive tree metabolism, has important role in determination of olive nutrient status and fertilizers requirements. Thus, the aim of our study was to define differences in leaf phosphorous (P), potassium (K), calcium (Ca) and magnesium (Mg) concentrations between Leccino and Istarska bjelica cultivars. The field experiment included total of 18 olive trees per cultivar, equally distributed in six locations all along Croatian Adriatic coast. Sampling for leaf bulk analysis was conducted during harvest, winter and pruning period (2017/2018) (n=54). In the greenhouse experiment, with 150 one-year old olive seedlings per cultivar, leaves were sampled for bulk and micro-PIXE analysis in November 2019 (n=3). Field experiment results shown that Leccino cv. leaves has higher bulk P, Ca and Mg concentrations when compared to Istarska bjelica cv.. In greenhouse experiment total Ca and Mg leaf concentrations were higher in Leccino cv. with elevated K concentration in Istarska bjelica cv.. Micro-PIXE analysis revealed that larger Ca and Mg bulk concentrations in Leccino cv. leaves can be linked to higher Ca concentration in epidermis and in leaf blade tissues as well as with higher Mg concentration in mostly all leaf tissues, with exception the bundle sheath cells and the main vascular bundle. While P concentration was higher in epidermis and spongy mesophyll of Leccino cv. leaves, K concentration didn’t differ between selected cultivars in any of the leaf tissues examined.