Fifth metatarsal avulsion fracture: a rational basis for postoperative treatment.
BACKGROUND
Lacking rational basis for the postoperative treatment of fifth metatarsal avulsion fractures.


METHODS
Biomechanical test of stability of tension banding and screw fixation of fifth metatarsal avulsion fractures in cadaver specimen, sonographic measuring of the maximum cross-section of the peroneus brevis muscle, electromyographic examinations of the activity of the peroneus brevis muscle at different loads and means of immobilization.


RESULTS
The forces acting on the base of the fifth metatarsal bone during voluntary activation of the peroneus brevis muscle or activation in the gait cycle are of the same magnitude as the failure forces of internal fixation. Immobilization of the talocrural joint achieves no reduction in muscle activation. Partial weight bearing reduces muscle activation.


CONCLUSIONS
The postoperative treatment after osteosynthesis of fifth metatarsal avulsion fractures should be partial weight bearing. For safety reasons we add an elastic ankle orthesis to prevent supination. A below-knee cast is not necessary.
Heineck
Jan
J
Klinik für Unfall-u, Wiederherstellungschirurgie, Universitätsklinik Carl Gustav Carus der Technischen Universität Dresden, Fetscherstr. 74, 01307, Dresden, Germany. jan.heineck@uniklinikum-dresden.de
Wolz
Martin
M
Haupt
Cornelius
C
Rammelt
Stefan
S
Schneiders
Wolfgang
W
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D008682:Metatarsal Bones / Q000601:surgery*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D011182:Postoperative Care; D016474:Weight-Bearing