Resurfacing elbow prosthesis: shape and sizing of the humeral component.
The sizing and dimensioning of a new unconstrained elbow prosthesis makes use of a geometric axis for humeral articulating surface definition, an axis which is precisely positioned with respect to extra-articular anatomical landmarks. The geometry of the joint was determined by a slicing and digitization technique. It was found that for the humerus an axisymmetric surface is evident and that there exists a centroidal axis which is mostly linear except for a portion at the posterior lateral flange of the trochlea. Sizing studies were carried out on dry bone anatomical specimens and, using a standardized X-ray technique, on the elbows of volunteer subjects. Seven dimensions were chosen for statistical analysis of the joint. A multi-variate normal distribution model, using only the first principal component was found to account for 70% of the variance; components 2 and 3 explained a further 19%. From this analysis, one series of three and five sizes of prosthetic dimensions were established for 95% overall coverage of population.
D001698:Biomedical Engineering; D001699:Biometry; D003201:Computers; D004551:Elbow Joint / Q000033:anatomy & histology; D006801:Humans; D006811:Humerus / Q000033:anatomy & histology; D007595:Joint Prosthesis; D011474:Prosthesis Design