SURGICAL MANAGEMENT OF UPWARD FIXATION OF THE PATELLA VIA MEDIAL PATELLAR LIGAMENT DESMOTOMY IN A LOWLAND TAPIR (TAPIRUS TERRESTRIS).

Tapirs are endangered terrestrial mammals that inhabit several continents. They have anatomical similarities to horses, sharing a common ancestral lineage. This article reports the case of a 14-yr-old female lowland tapir (Tapirus terrestris) presented for intermittent lameness due to upward fixation of the patella causing extension of the limb in the caudal phase of the stride. Medial patellar desmotomy was performed under general anesthesia, correcting the problem. To date there are no reports of this condition or treatment recommendations in tapirs. An anatomical study including stifle dissection, advanced MRI, and CT was performed in a separate lowland tapir. According to the clinical case and the anatomical findings in the other lowland tapir, upward fixation of the patella may occur in the tapir, although the anatomy varies slightly from that of the horse. Because the lowland tapir does not have parapatellar cartilage or as large of a medial patellar ligament or medial trochlea of the distal femur compared to the horse, more severe disease secondary to complete or persistent upward fixation of the patella may not occur in tapirs. Rather, mild forms of the disease associated with intermittent upward fixation of the patella or delayed patellar release appear more likely in the tapir.

Low Mg content on Ti-Nb-Sn alloy when in contact with eBMMSCs promotes improvement of its biological functions.

Magnesium is a metal used in the composition of titanium alloys and imparts porosity. Due to its osteoconductive, biocompatible and biodegradable characteristics, its application in the development of biomedical materials has become attractive. This study aimed to evaluate the influence of magnesium present in porous Ti-Nb-Sn alloys, which have a low elastic modulus in adhesive, osteogenic properties and the amount of reactive intracellular oxygen species released in mesenchymal stem cells derived from bone marrow equine bone (eBMMSCs). Mechanical properties of the alloy, such as hardness, compressive strength and elastic modulus, were analyzed, as well as surface morphological characteristics through scanning electron microscopy. The evaluation of magnesium ion release was performed by atomic force spectroscopy. The biological characteristics of the alloy, when in contact with the alloy surface and with the culture medium conditioned with the alloy, were studied by SEM and optical microscopy. Confirmation of osteogenic differentiation by alizarin red and detection of ROS using a Muse® Oxidative Stress Kit based on dihydroetide (DHE). The alloy showed an elastic modulus close to cortical bone values. The hardness was close to commercial Ti grade 2, and the compressive strength was greater than the value of cortical bone. The eBMMSCs adhered to the surface of the alloy during the experimental time. Osteogenic differentiation was observed with the treatment of eBMMMSCs with conditioned medium. The eBMMSCs treated with conditioned medium decreased ROS production, indicating a possible antioxidant defense potential of magnesium release.