title: Observed changes in first metatarsal and medial cuneiform positions after first metatarsophalangeal joint arthrodesis.
abstract: The first intermetatarsal angle (IMA) is known to decrease after first metatarsophalangeal joint arthrodesis, although the exact mechanism by which this decrease occurs is not known. We measured the first IMA and obliquity of the medial cuneiform on anteroposterior weightbearing preoperative and postoperative radiographs in 86 feet and analyzed the statistical correlation between the IMA and the medial cuneiform angle. A change in the first IMA after first metatarsophalangeal joint fusion showed a strong positive correlation with a change in cuneiform obliquity (p < .0001). This finding was consistent in the direction and magnitude in each of 3 clinical subgroups: normal, p = .087; moderate deformity, p = .011; and severe deformity, p = .10. A comparison of the preoperative IMA and cuneiform obliquity revealed a trend toward a positive relationship but did not reach statistical significance (p = .08). The preoperative association between the IMA and medial cuneiform obliquity was not significant in any clinical subgroup, and the postoperative association between the IMA and cuneiform obliquity was not significant (p = .65). Clinical subgroup analysis showed no significant association between the IMA and the normal (p = .73) and moderately (p = .69) deformed feet, although the postoperative association between the IMA and cuneiform obliquity in the severely deformed group was significantly (p = .034) positive. A linear relationship between the reduction of the first IMA and medial cuneiform obliquity after metatarsophalangeal joint fusion was observed. Our findings suggest that frontal plane rotation influences cuneiform obliquity.
authors.affiliation: UnityPoint Clinic, Trinity Regional Medical Center, Fort Dodge, IA; Adjunct Professor, Des Moines University College of Podiatric Medicine and Surgery, Des Moines, IA. Electronic address: daytonp@me.com.
authors.forename: Paul
authors.initials: P
authors.lastname: Dayton
authors.affiliation: Podiatric Medical Student, Des Moines University College of Podiatric Medicine and Surgery, Des Moines, IA.
authors.forename: Merrell
authors.initials: M
authors.lastname: Kauwe
authors.affiliation: Department of Biology, Brigham Young University, Provo, UT.
authors.forename: John S K
authors.initials: JS
authors.lastname: Kauwe
authors.affiliation: Assistant Professor, Des Moines University College of Podiatric Medicine and Surgery, Des Moines, IA.
authors.forename: Mindi
authors.initials: M
authors.lastname: Feilmeier
authors.affiliation: Podiatric Medical Student, Des Moines University College of Podiatric Medicine and Surgery, Des Moines, IA.
authors.forename: Jordan
authors.initials: J
authors.lastname: Hirschi
mesh_terms: D001174:Arthrodesis; D006215:Hallux Valgus / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008682:Metatarsal Bones / Q000000981:diagnostic imaging*; D008683:Metatarsophalangeal Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D011859:Radiography; D013639:Tarsal Bones / Q000000981:diagnostic imaging*
keywords: 4; atavism; first ray; fusion; hallux valgus; motion; rotation