Method for volumetric assessment of edge-wear in ceramic-on-ceramic acetabular liners

This paper details a novel method to characterize and quantify edge wear patterns in ceramic-on-ceramic acetabular liners using a roundness measurement machine to measure the post-wear surface. A 3D surface map is produced which encompasses the measured surface covering the wear patch, the uncontrolled edge geometry and form of the bearing surface. The data is analysed to quantify linear penetration and volume. The developed method was applied in a blind study to a set of six 36 mm ceramic- on-ceramic acetabular cup liners that were measured and analysed to characterise the edge wear. The in-vitro linear wear penetration ranged from 10 μm to 30 μm. The computed volumetric wear results obtained from the blind roundness measurement study were compared against the measured gravimetric results indicating a strong correlation between the results (0.9846). This study has also highlighted that measured liners exhibited an area of localised edge wear locates above the bearing surface as well as a smearing effect on the bearing surface caused by debris from edge wear. A study was carried out to test the repeatability of the measurement method and the inter-operator variability of the analysis. The results of the study show a standard deviation for the entire measurement and analysis process of 0.009 mm3 for first user and 0.003 mm3 for second user over twenty datasets. Hence the method displays high repeatability of the measurement and analysis process between users. This method allows for the delineation of form and wear through the determination of local geometry changes on what is essentially a freeform surface. The edge geometry is only partially controlled from a GD&T perspective and its geometry relative to the bearing surface varies from part-to-part. This method whilst being subjective allows for the determination of wear in this area with a high level of repeatability. However the limitation of this method is that it can only measure 5mm wide band of the liner due to the limited gauge travel range of 2mm

Anterolateral approach with tibial tubercle osteotomy versus standard medial approach for primary total knee arthroplasty: does it matter?

The purpose of this prospective consecutive multicenter study was to investigate whether the type of surgical approach (medial parapatellar (MPA) or lateral parapatellar with tibial tubercle osteotomy (TubOT)) influences the early clinical and radiological outcomes of primary total knee arthroplasty (TKA)

Distributed tracking control problem of Lipschitz multi-agent systems with external disturbances and input delay

This paper addresses the distributed tracking control problem for Lipschitz nonlinear multiagent systems (LNMASs) in the presence of external disturbances and input delay. For this end, a distributed tracking control algorithm is proposed for LNMASs that guarantee each agent can estimate and track a nonlinear target. The suggested algorithm is developed based on a future state predictor and a finite time estimator to cope with the tracking control problem for LNMASs with input delay and external disturbances. Finally, the efficiency of the proposed algorithms is illustrated by simulation results

COVID-19 in Combination with HLH in a Child with Severe Aplastic Anemia

Since December 2019, the coronavirus (COVID-19) has spread all over the world. This disease may present differently in immune-compromised persons. Some of the virus’s impacts have yet to be identified. In this case report, we report a three-year-and-three-month-old child with aplastic anemia who was concurrently infected with COVID-19 and HLH (hemophagocytic lymphohistiocytosis). She was referred to our center for further investigation of aplastic anemia with concurrent fever. Through examination due to splenomegaly, more evaluations were done. During admission, the PCR test for COVID-19 became positive, however, because of the fulfillment of the HLH criteria, she was diagnosed with this disease development. She was treated for HLH with IVIG and Dexamethasone while getting COVID-19 treatment. Following medicines and follow-up, her WBC and Hb count started to rise, aside from the PLT count. She continues to receive PLTs because of her thrombocytopenia till a suitable donor for BMT (Bone Marrow Transplant) is found. This case scenario highlights the COVID-19 concurrent complications for paying attention to underlying disease for better diagnosis and management. Keywords: COVID-19, pediatrics, pancytopenia, aplastic anemi

COVID-19 in Combination with HLH in a Child with Severe Aplastic Anemia

Since December 2019, the coronavirus (COVID-19) has spread all over the world. This disease may present differently in immune-compromised persons. Some of the virus's impacts have yet to be identified. In this case report, we report a three-year-and-three-month-old child with aplastic anemia who was concurrently infected with COVID-19 and HLH (hemophagocytic lymphohistiocytosis). She was referred to our center for further investigation of aplastic anemia with concurrent fever. Through examination due to splenomegaly, more evaluations were done. During admission, the PCR test for COVID-19 became positive, however, because of the fulfillment of the HLH criteria, she was diagnosed with this disease development. She was treated for HLH with IVIG and Dexamethasone while getting COVID-19 treatment. Following medicines and follow-up, her WBC and Hb count started to rise, aside from the PLT count. She continues to receive PLTs because of her thrombocytopenia till a suitable donor for BMT (Bone Marrow Transplant) is found. This case scenario highlights the COVID-19 concurrent complications for paying attention to underlying disease for better diagnosis and management