Foot and Ankle Amputations

Level

 

Level not predicated by angiography

- best is appearance of ST at time of surgery as judged by experienced surgeon

 

Toe

 

Technique

- dorsal-plantar or side-to-side flap

- tension free closure

- high reamputation rate in PVD / DM

 

Hallux

 

Technique

- stabilise sesamoids in hallux amputation

- leave base of P1 to prevent adjacent toes falling into gap

- this also preserves plantar fascia

- tenodesis of FHB

 

Second Toe

- beware of HV postoperatively

- can use insert

- may need to fuse 1st MTPJ

 

Ray 

 

Indications

- single medial or lateral ray that has an infected ulcer

- multiple resections may excessively narrow foot

- central ray amputations are inferior to Lis Franc amputation

 

Technique

- racquet shaped incision based on involved MT to avoid NV bundles

- most are partial ray resections

- leave base

 

Prosthesis

- Oxford extra-depth shoes with custom insoles

 

Lisfranc

 

Technique

- at TMT

- create long plantar flap

- smooth curve fashioned 

 

Precautions

- muscle balance

- Tendo achilles lengthening may be required to avoid later equinus

- muscle reattachment especially Peroneus brevis (try to preserve base fifth MT)

 

Prosthesis

- may initially require AFO

- usually shoe filler eventually

 

Chopart 

 

Concept

- excellent amputation

- through midfoot leaving only talus and calcaneum

 

Advantage over Symes

- no problems with heel pad migration

- functional end bearing stump

- no LLD

 

Technique

- original procedure without transfer had problems with late equinus & varus

- reattach to talus neck T. Ant / T Post / EHL / EDL

- Tendo achilles lengthening

 

Prosthesis

- AFO with foot plate & filler

- slipper style prosthesis

 

Boyd

 

Concept

- talectomy / forward shift of calcaneum / calcaneotibial arthrodesis

 

Advantage over Symes

- preserves length & growth centres

- no heel pad migration

 

Disadvantage

- bulky stump

- poorer cosmesis

 

Technique

- dorsal incision from tip LM to 1 inch below MM

- planter incision transversely across sole at level MT bases

- amputate forefoot through Chopart joint

- excise talus

- anterior calcaneal osteotomy transversely across calcaneum at level of peroneal tubercle

- shift calcaneum anteriorly

- excise cartilage of distal tibia / fibula & superior calcaneum

- calcaneo / tibial arthrodesis

- steinman pin through calcaneum and tibia 

- close over drains

 

Pirigoff 

 

Concept

- talectomy 

- anterior 1/2 calcaneum excised 

- rotated 90°

- calcaneo-tibial arthrodesis

- used in children to preserve length & growth centres

 

Symes

 

Principle

- through ankle joint

- may allow ambulation with out prosthesis in emergencies 

- end-bearing with stable gait pattern

- can still fit ankle prothesis

- women can be unhappy with cosmesis

 

Technique

- from tip of LM to 1 inch below tip MM across front of ankle

- then continue plantarward under sole between same points / MT bases

- need to preserve large post heel pad

- excise talus & calcaneus

- remove malleoli at level of joint & contour 

- divide arteries / veins / nerves above levels of flaps

- anchor heel pad to anterior tibia via intra-osseous sutures 

 

Problems

- heel pad migration is biggest complication

- don't trim dog ears or can get skin slough