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Trapezium components from two uncemented total joint replacements were compared in a three-dimensional finite element model. A 100 N axial and angular load was applied in a normal and an osteoporotic bone model. The axial deformation and maximum periprosthetic stress are greater for the Elektra^TM than the Motec CMC^® cup. The Motec CMC^® design is less sensitive to changing bone quality. The Elektra^TM cup transmits more stress to the cortical bone rim in all load conditions, but under angular loading the proportionate increase in stress is lower. The Motec CMC^® design distributes the stress and contact pressure more evenly, whereas the Elektra^TM transfers most of the load to the cortical bone rim and the screw hole base. The design features that are believed to be of greatest significance for the differences are the raised centre of rotation of the Motec CMC^® cup and the collar acting as a lever arm.

Analysis of knee kinematics and ground reaction forces (GRFs) is widely used to determine compensatory mechanisms of people with anterior cruciate ligament deficiency (ACLD). However, the practicality of the measurements is subject to their reliability during different trials. This study aims to determine the reliability and repeatability of knee joint rotations and GRFs in people with ACLD during stair ascent. Eight participants with unilateral ACL-deficient knees performed five trials of stair ascent with each leg. The movements were captured by VICON motion analysis system, and GRF components were recorded using force plate. Three-dimensional tibiofemoral joint rotations were calculated. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of multiple correlation (CMC) were calculated ACL-deficient legs showed lower absolute reliability during swing ($\mathrm{\text{SEM}}=1.6$–6.4) than stance phase ($\mathrm{\text{SEM}}=0.6$–2.2) for knee joint rotations. Moderate to high average measure ICCs (0.59–0.98), relative reliability, were achieved for injured and uninjured sides. The results also demonstrated high repeatability for the knee joint rotation ($\mathrm{\text{CMC}}=0.78$–0.97) and GRF ($\mathrm{\text{CMC}}=0.87$–0.99). The outcomes of this study confirmed the consistency and repeatability of the knee joint rotations and GRFs in ACL-deficient subjects. Additionally, ACL-deficient legs exhibited similar levels of reliability and repeatability compared to contralateral legs.

Aggregation kinetics of a porphyrin derivative in the absence and presence of different concentrations, below and above the critical micelle concentration (CMC) of three ionic liquids (ILs); 1-octyl-3-methylimidazolium, 1-dodecyl-3- methyl imidazolium and 1-octadecyl-3-methylimidazolium chloride was studied using molecular dynamics simulation. Effect of IL, with different chain lengths on the aggregation of a porphyrin derivative, 5,10,15,20-tetrakis(2,5-dihydroxyphenyl)porphyrin, was investigated. The low amount of each ionic liquid (below CMC) observed to favors the formation of aggregates; further increasing ionic liquid concentration leads to the destabilization of aggregates. The compared calculated rate constants also support these results. Aggregation of imidazolium ILs proved to take place with longer alkyl chains that favors aggregation.

Background: The objective was to quantify joint laxity in healthy volunteers by measuring the passive axial rotation of the trapeziometacarpal joint using the axial rotation test.

Methods: Eighty volunteers (34 men and 46 women) were subjected to the axial rotation shear test and the degree of total rotational motion (TRM) was assessed. Volunteers were divided into Group I with a range of 18–50 years old and Group II for 51 years and older. Statistical analysis was performed.

Results: The average TRM in Group I was 32.3 mm for women, and 27.4 mm, for men (p = 0.04). The average TRM in women of Groups I and II, was 32.3 and 21.6 mm respectively, (p < 0.001). The average TRM in men of Groups I and II, was 27.4 and 19.4 mm (p < 0.001). In Group II the average TRM of women was 21.6 mm, and for men was 19.4 mm, which was not significantly different.

Conclusions: Young women have greater degree of rotational laxity in the TM joint compared to men of the same age group and to older women. The axial rotation test can quantify the degree of rotational laxity of the TM joint.