Nomenclature
- Prostheis technically embraces all substitutes for bodily defects
- Transtibial/Transfemoral
- Trauma/PVD/Tumor/Gangrene/Congenetal
- MESS
- Insensate plantar surface
S/R: 2 weeks
- Shrinker sock 2weeks
- casting 2 weeks
- Prosthesis
- Standing for 15 mts 2 weeks
- Gait training 6weeks
Higher the amputation
- Patients self regulated walking speed decreases
- Higher energy expenditure
Symes
- Advantages: longer stump
- Patients self regulated walking speed more
- Less energy expenditure
- Walk on residual stump
- Disadvantages
- Bulky socket/need C/L raise
- Fat pad migration
Transtibial
- Easier to match height side to side
- Better cosmeses
Through knee vs trans femoral
- Adv
- Better self regulated walking speed
- less energy expenditure
- Bulbous ship give better stability for prosthesis
- Disadv
- decrease cosmoses
- asymmetric knee
- limited knee component availability
- Increased tissue trauma and painful residual stump
Ideal length
- Always need a longer lever arm
- Space for component, cosmetically pleasing
- 5 inch rule
- Minimum: retain tibial tubercle and patella tendon
Soft tissue
- Posterior flap: Diameter + 1 cm
- Fibula 1cm shorter than tibia
- if interosseous disrupted, syndesmotic screw
Tranfemoral
- 5 inch rule
- Minimum 3 inch above knee joint
- If not, cosmetically displeasing and fitting not good
- Minimum 2 inches below LT
Prerequisites for trans tibial
- Full knee extension
- 70degree flexion
- Full hip extension
- 80 % strength of uninjured limb
Pre requisites trans femoral
- Full range hip movement
- < 10 degree FAB deformity
Soft tissue coverage
- Full thickness skin
- mobile non adherent Muscle mass
- Durable
- Allow pistoning
- Distribute load to bone
- dissipate pressure during loading
Myodesis/myoplasty
- Do combination of both, ie anchor adductor muscle to femur
- Do at resting status of joint
- Avoid adductor roll
- Avoid abductor lurch
Load transfer
- Direct load transfer: end bearing (through knee or ankle)
- Wide metaphysis means larger surface area
- Less young modulus
- this dampen the load
- Indirect: total contact
End bearing prosthesis
- Socket: provide impact dampening
- suspension: prevents falling off
- Provide satisfactory alignment
Indirect load transfer
- Trans tibial/trans femoral
- Terminal surface is not capable of load transfer
- Too small surface area
- Bone is stiff
- Cannot dampen the forces
Snug fit: hydraulic cylinder
- 10 degree FAD in hip
- 10 degree FAD in knee
Complications
- Residual limb pain (40)
- Phantom pain (70)
- distressing pain(40)
- Neuroma
- contracture
- infection
- bony prominences
- veracious hyperplasia
Parts
Preparatory/definitive
- Socket
- Suspension
- Pylon/shank
- Foot
- Mechanical knee joint
PTB/TSB (total surface bearing)
- PTB
- Medial tibial flare
- popletial counter pressure
- patellar tendon
- supracondylar/suprapatellar suspension
TSB
- Distribute weight
- Pin and silicon liner
- vacuum assisted suction suspension
Shank
- Aircraft grade aluminium/carbon
- Shock absorption
- Transverse rotator
Knee prosthesis
- Single axis knee
- Stance phase locking
- 4 bare knee
- Hydraulic knee
- Pneumatic
- Microprocessor
Foot
- SACH
- Carbon feet
- Dynamic response feet (articulated/non articulated)
- Short/long keel
Foot amputations
- Toe
- Ray
- Mid foot lisfranc
- Hind foot
- chopart: CC/TN
- Parogoff: Calcanium
- Syme: through ankle
Midfoot
- Inadequate lever arm for propulsion
- Late varus deformity (Tant transfer)
- Late equinous (AT lengthen)
- So syme is better
Syme
- Patent Post artery
- Apex of incision just anterior to mid anterior border of medial and lateral malleoli
- Remove malleoli
- Heel pad to anterior rim tibia
Upper limb
- Prehensile (sensory interaction)
- Visual guidance (decrease if in full pronation)
- Shoulder (centre of functional sphere)
- Hand(extreme of functional sphere)
- Elbow (Calliper to position hand)
Trans radial
- through wrist better
- volar flexors to radius and ulna (myodesis)
- Fit in 5 days (myoelectric motor)