Principles

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