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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.

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.