Strength of human metatarsal bones under repetitive loading

Abstract

The fatigue life of 51 intact human metatarsals was tested in a Sonntag Flexure Fatigue machine equipped with an automatic counter and shutoff. Bones from eight adult males and three females were used. Nine of the individuals were white and two were Negro. No bones showed any gross pathology. Ten bones were tested wet, forty-one dry. The repetitions to failure with a 15-lb. load, the maximum applied, varied from 1,000 to 10,297,000 for the dry specimens and from 150,000 to 13,908,000 for the wet ones. The greatest variation between the minimum and maximum number of repetitions to failure was 10,287,000 and 10,966,000 repetitions for the dry and wet specimens, respectively. Metatarsals II and III had the longest fatigue life when wet while metatarsals IV and V had the greatest fatigue life when dry. No consistent relations were found between the fatigue life of the bones and their size or the age of the individual from whom they were obtained. The fractures produced were of the comminuted and oblique types found clinically. As far as is known the fatigue life of intact bones has not been previously studied. Submitted on June 30, 1958