Description and classification of degenerative bone changes in the distal joint surfaces of the humerus

Abstract

Abstract This paper attempts to provide the descriptive and classificatory basis for a clearer understanding of degenerative changes on the humeral elbow. Two general problems are outlined. One in the study of the elbow as an indicator of stress in making comparisons between populations. Preliminary data on two series, Alaskan Eskimos and Peruvian Indians, indicate a much higher incidence among the Eskimos (18% as compared with 5% in the Peruvians). The second problem results from the unique morphology and function of the elbow. Mechanical stress on the humeral elbow is fairly evenly distributed over the entire surface of the trochlea in contrast with the capitulum where stresses are localized away from the edge in approximately the geometric center of the capitulum. Hypertrophic bone formation is much greater on the periphery of the trochlea where mechanical stress is frequent than on the edge of the capitulum where mechanical stress is infrequent. This observation supports the generalization that local stress is an important factor stimulating the formation of hypertrophic bone.