title: The offset V osteotomy versus the modified Austin with a longer plantar arm: a comparison of mechanical stability.
abstract: Several studies have tested the strength and various fixation modalities of the long dorsal arm offset V osteotomy, and have proven it to be a stable construct when fixated properly. We believe that a modification of the traditional Austin cuts, with a slightly longer plantar arm, lends itself to greater stability because instead of ground reactive forces applying a distraction moment on the osteotomy, the ground actually compresses the osteotomy leading to greater stability and less chance of failure. We compared the mechanical stability of the long dorsal offset V osteotomy to the slightly longer plantar arm osteotomy using 20 sawbone models, 10 in each study group. The offset V osteotomies were all fixated with two 2.7-mm stainless steel screws through the dorsal arm of the osteotomy, and the longer plantar arm osteotomies were fixated with one 2.4-mm stainless steel screw through the plantar arm of the osteotomy. Results of testing with the 858 Mini Bionix materials testing device, showed a mean load at failure of the long dorsal arm osteotomies of 142.26 N (range 53.16-235.45 N). Mean load at failure of the longer plantar arm osteotomies was 280.07 N (range 184.91-337.39 N). There was a significant difference in the ultimate load at failure between the 2 groups (P < .0001). There was no significant difference in displacement (P = .18) or stiffness (P = .54). The results of our study indicate that the slightly longer plantar arm osteotomy is a more stable construct than the long dorsal arm offset V osteotomy.
authors.affiliation: Dekalb Medical, Decatur, GA 30033, USA. rravenell18@gmail.com
authors.forename: Rahn A
authors.initials: RA
authors.lastname: Ravenell
authors.forename: Carl A
authors.initials: CA
authors.lastname: Kihm
authors.forename: Angela S
authors.initials: AS
authors.lastname: Lin
authors.forename: Francis X
authors.initials: FX
authors.lastname: Garing
mesh_terms: D001863:Bone Screws; D006801:Humans; D008682:Metatarsal Bones / Q000601:surgery*; D008953:Models, Anatomic; D010027:Osteotomy / Q000379:methods*; D013314:Stress, Mechanical; D016474:Weight-Bearing