Epidemiology
2/3 PVD
1/3 Trauma
5% Tumour
1% Congenital
Indications
Dead / Dying / Dangerous / Damn nuisance
Indications for amputation in open tibial fracture
Lange et al J Trauma 1985
Absolute Indications (1 of 2)
1. Complete tibial nerve disruption
2. Crush injury with warm ischaemia time > 6 hours
Relative indications (2 of 3)
- serious associated polytrauma
- severe ipsilateral foot trauma
- projected long course to full recovery
MESS (Mangled Extremity Severity Score) guide only
- involve patient in decision
Aims
Aim
- maximum function
- minimum complication rate
Ambulatory
- most distal level that will achieve healing & provide functional stump
Non-ambulatory
- improve sitting balance, transfers & nursing care
- through knee best in non ambulatory
- balanced amputation
- no FFD of knee, which limits impinging on bed and development of sores
Principles of Good Outcome
1. Reconstructive approach
- not considered as a failure
2. Team approach
- early involvement of rehab / prosthetist
3. Pre-op assessment & planning
4. Patient explanation & involvement
5. Good surgical technique
- optimal limb length
- good residual joint
- excellent ST (non adherent and durable) with muscle cushioning
6. Early prosthetic fitting
7. Amputee rehabilitation
8. Appropriate prosthesis prescription
Energy Cost of Level
O2 Consumption inversely proportional to
- length of residual limb
- number of joints preserved
Increase over baseline
- long BKA 10%
- medium BKA 20%
- short BKA 40%
- medium AKA 60%
- hindquarter 100% +
- wheelchair ~ 0%
Maximum walking speeds
- normal = 82 m /min
- BKA = 50-70 m /min
- AKA = 40-55 m /min
Geriatric with PVD & AKA is virtually at maximum energy expenditure
End Bearing Vs Non- End Bearing
End Bearing / disarticulation
Weight taken through end of stump
- scar non-terminal
- bone end metaphyseal, not hollow diaphyseal
- usually joint disarticulation
- end bearing prosthesis used
Non End Bearing / transosseous
Commonest
- intimate fit needed to distribute load over as wide a load as possible
- load transfer usually over the entire residual limb
- scar can be terminal
- usually trans-osseous amputations where end bearing would be too painful
Surgery
Planning
Maximise length & joints
Vascularity
Skin cover
Infection
Prosthetic
Skin Flaps
- careful planning
- Atraumatic ST handling
- keep skin flaps thick
- avoid unnecessary dissection between tissue planes
- Non-terminal if end bearing
- Terminal if °End bearing
- Full thickness skin
- Avoid SSG
Bone
- leave long
- Bevelled bone end
- Min Periosteal strip in adults
- strip 0.5 cm in kids to prevent terminal overgrowth
Muscles
Aim
- Mobile non-adherent muscle mass
Stabilisation of distal ends
- provides padding over bone
- prevents atrophy
- avoids FFD by balancing deforming forces
- improves lever arm length i.e. avoid trendelenberg in AKA
Techniques
- suture at functional length
- Myodesis - suture to bone
- Myoplasty - suture to muscle or ST
Nerve
- Sharp division of nerve under gentle non-crushing retraction
- Allows cut end to retract into ST
- inevitable neuroma cushioned by muscle
- Clamping increases CRPS II
- Ligature / Diathermy has no effect
Closure
- Excellent haemostasis
- Delayed closure as needed
IPSF vs EPSF
Immediate Post surgical Prosthesis Limb Fitting IPSF
- Rapid application of limb < 5/7
- Early Weight bearing
- Suitable for traumatic amputee's
- Increased wound complications due to rapid stump shrinkage in first 2weeks
Early Post surgical Prosthesis Limb Fitting
- Better as most rapid stump shrinkage has occurred
- 14-21 days
- Less wound complications
Complications
Pain
1. Phantom Sensation
- Sensation that limb still present
- Occurs in most patients
- Usually diminishes over time
2. Phantom Pain
Burning pain in Phantom limb
- Occurs in ~10% of pts
- usually settles 4- 6 weeks
Treatment
- Increase prosthetic use
- Physio
- TENS
3. Causalgia / RSD
Pain in stum - Burning / throbbing etc
Non-op Treatment
- Massage, Compression, TENS
- Varied success
Operative Treatment
- Limited success
Prevention
- Effective
- Peri-op Epidural
- Post-op intraneural anaesthesia
4. Mechanical Causes
- Sharp bone end
- Poor ST envelope
- Unstable skin
- Ill fitting prosthesis
5. Other Causes
- Radicular pain
- Proximal OA
- Ischaemic pain
- Neuroma not uncommon cause consider LA injection for Dx
Oedema
Common
- Minimise with rigid dressings
- If soft dressings used, stump wrapping important
Excessive proximal tightness results in
- Proximal narrowing
- Increased distal oedema
- Dumb Bell stump
Contractures
Usually occur between amputation & prosthetic fitting
Hip In AKA
Deformities
- FFD
- abduction
Minimised by
- Adductor Magnus / Hamstring stabilisation
- Quads myodesis to posterior femur
- Avoidance of stump on pillow
- Early active & passive exercises
- Prone lying
Knee in BKA
Deformity
- FFD
Minimised by
- LL rigid dressings
- EPLF
- Quads strengthening
- HS stretching
- Difficult to treat once established because of short lever arm
Wound
Breakdown not uncommon
- Especially in PVD & DM
Dermatological
Numerous problems
- Epidermoid cysts
- Contact dermatitis
- Superficial skin infections