biomechanics

Background

DefinitionHallux Valgus Severe

 

Bunion

- medial prominence of head of 1st MT

 

Hallux Valgus

- medial deviation 1st MT

- lateral deviation of great toe

 

Anatomy

 

Metatarsal head

- has 2 grooves separating ridge (cristae)

 

Subtalar and Triple Arthodesis

Biomechanics

 

Able to achieve relatively high level of function after STJ fusion

- previously believed that isolated STJ fusion should not be performed

- believed that triple arthrodesis was operation of choice for hindfoot

- STJ fusion has superior result with less stress on AJ

 

Average loss of DF 30% / PF 10%

 

Position of hindfoot determines flexibility of transverse tarsal (CCJ & TNJ) joints

- imperative that fusion be positioned in ~ 5o valgus 

Background

AnatomyDislocated Ankle

 

Bony

- 90% load through plafond to talus

- 10% load through lateral talofibular articulation

 

Ligaments

 

A.  Lateral Ligament Complex

 

ATFL (Anterior Talo-Fibular Ligament) 

- tight in plantar flexion