title: Stress at the second metatarsal bone after correction of hammertoe and claw toe deformity: a finite element analysis using an anatomical model.
abstract: BACKGROUND
  We used finite element analysis to evaluate three techniques for the correction of hammertoe and claw toe deformities: flexor digitorum longus tendon transfer (FDLT), flexor digitorum brevis tendon transfer (FDBT), and proximal interphalangeal joint arthrodesis (PIPJA).
  
  
  METHODS
  We performed a finite element analysis of FDLT and FDBT compared with PIPJA of the second toe using multislice computed tomography and 93 tomographic images of the foot obtained in a healthy 36-year-old man.
  
  
  RESULTS
  The PIPJA showed a significantly higher increase in traction and compressive stresses and strain at the medial aspect of the shaft of the second metatarsal bone compared with FDLT or FDBT (P < .01). Mean ± SD compressive stresses increased to -4.35 ± 7.05 MPa compared with the nonsurgical foot (-3.10 ± 4.90 MPa). It can, therefore, be hypothesized that if PIPJA is used to correct the hammertoe and claw toe deformities, it could also increase traction and compressive stresses and strain in the metatarsals during running and other vigorous activities.
  
  
  CONCLUSIONS
  There is a biomechanical advantage to performing FDLT or FDBT instead of PIPJA to surgically treat a hammertoe or claw toe deformity. In addition, tensile strain at the dorsal aspect of the second metatarsal bone when performing PIPJA increases the risk of metatarsalgia or stress fracture in patients at risk.
authors.affiliation: Group of Structural Mechanics and Materials Modeling, Aragón Institute for Engineering Research, University of Zaragoza, Zaragoza, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Bayod
authors.forename: Ricardo
authors.initials: R
authors.lastname: Becerro de Bengoa Vallejo
authors.forename: Marta Elena
authors.initials: ME
authors.lastname: Losa Iglesias
authors.forename: Manuel
authors.initials: M
authors.lastname: Doblaré
mesh_terms: D000328:Adult; D001174:Arthrodesis / Q000379:methods; D001696:Biomechanical Phenomena; D020342:Finite Element Analysis; D005530:Foot Deformities / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D037801:Hammer Toe Syndrome / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008682:Metatarsal Bones / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D008953:Models, Anatomic; D061330:Multidetector Computed Tomography; D013314:Stress, Mechanical; D013709:Tendon Transfer / Q000379:methods