关键词: 跖骨, 应力性骨折, 应变

Abstract: ObjectiveTo evaluate the strain of the weight-bearing metatarsal bone. Methods6 fresh-frozen cadaveric lower extremities were dissected to expose the dorsal aspect of metatarsal. Bone segments were clarified for adherence of strain-gauges while feet kept intact. Then vertical downward axial load was exerted to distal tibia at a 2 mm/min velocity, from 0 N to 1200 N with one minute interval of 200 N leveled loading augment each for sampling. Superficial strain of the metatarsal was measured by resistance strainmeter methods. ResultsThe strain increased gradually with axial loading, and compress force was always found at every marked bone. The strain of every marked bone was significantly different at the same loading (P<0.05). As to the strain of the middle of the metatarsal, the sequence was the second metatarsal＞the third metatarsal＞the fourth metatarsal＞the first metatarsal＞the fifth metatarsal. As to the strain of the second metatarsal, the sequence was the middle＞the neck＞the base. ConclusionThe peak strain was found at the middle of the second and third metatarsal with axial loading, which prompts the stress fractures of the second and third metatarsal are most common, especially the middle of the second metatarsal.

Key words: metatarsal bone, stress fracture, strain