title: Proximal first metatarsal opening wedge osteotomy: geometric analysis on saw bone models.
abstract: BACKGROUND
  For hallux valgus correction, distal first metatarsal osteotomy is generally used for minor to moderate deformities, diaphyseal osteotomy for moderate deformities and basal osteotomy or arthrodesis for severe deformities. With the advent of locking plates, there has been renewed interest in opening wedge basal osteotomy.
  
  
  OBJECTIVE
  We undertook this study in order to understand the power and limitations of this osteotomy.
  
  
  METHODS
  Proximal opening wedge osteotomies were performed on saw bone models in four orientations, with three different wedge sizes: (1) perpendicular to the ground (PG); (2) perpendicular to the shaft (PS); (3) perpendicular to shaft with 30° declination (DEC); (4) 30° oblique (OB). Pre- and post-osteotomy measurements were made of axial and plantar translation and inter-metatarsal angle.
  
  
  RESULTS
  Plantar translation and intermetatarsal angle correction increased with increasing wedge size. The DEC osteotomy produced the greatest increase in length of metatarsal shaft, while the PS osteotomy gave the least. The most plantar translation was achieved with the DEC osteotomy. Overall, the PS osteotomy gave the largest correction of the intermetatarsal angle.
  
  
  CONCLUSIONS
  Although there are several published clinical case series of the proximal opening wedge osteotomy, this is the first study to fully evaluate its geometry.
authors.affiliation: Heatherwood and Wexham Park Hospitals, NHS Foundation Trust, Heatherwood Hospital, London Road, Ascot, SL5 8AA, UK.
authors.forename: R
authors.initials: R
authors.lastname: Kugan
authors.affiliation: Heatherwood and Wexham Park Hospitals, NHS Foundation Trust, Heatherwood Hospital, London Road, Ascot, SL5 8AA, UK. Electronic address: verity_currall@hotmail.com.
authors.forename: V A
authors.initials: VA
authors.lastname: Currall
authors.affiliation: Heatherwood and Wexham Park Hospitals, NHS Foundation Trust, Heatherwood Hospital, London Road, Ascot, SL5 8AA, UK.
authors.forename: P
authors.initials: P
authors.lastname: Johal
authors.affiliation: Heatherwood and Wexham Park Hospitals, NHS Foundation Trust, Heatherwood Hospital, London Road, Ascot, SL5 8AA, UK.
authors.forename: C I C
authors.initials: CI
authors.lastname: Clark
mesh_terms: D006215:Hallux Valgus / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008682:Metatarsal Bones / Q000601:surgery*; D008683:Metatarsophalangeal Joint / Q000473:pathology; D008953:Models, Anatomic; D010027:Osteotomy / Q000379:methods*
keywords: Basal osteotomy; Geometry; Hallux valgus; Opening wedge