KEY NOTES CHAPTER 6: LOWER LIMB - Trauma. Flashcards
What lower limb fracture classifications are you aware of?
∘ Gustilo and Anderson (1976)
∘ Hannover Fracture Scale-97 (HFS-97) (1982)
∘ Byrd and Spicer (1985)
∘ Predictive salvage index (PSI) (1987)
∘ Mangled Extremity Severity Score (MESS) (1990)
∘ The AO soft tissue grading system (1991)
∘ Limb salvage index (LSI) (1991)
∘ Nerve injury, ischemia, soft tissue, skeletal, shock and age of patient (NISSSA) (1994)
∘ Ganga hospital score (2006)
∘ Bastion classification (2012).
What Gustilo type fracture is most common?
60% Gustilo III, of which 60% is IIIB.
Annual incidence 5 per 100,000.
Tell me about the Gustilo and Anderson Classification.
Type I
• Open fracture with a wound <1cm long and clean.
Type II
• Open fracture with a laceration >1cm long without extensive soft tissue damage, flaps or
avulsions.
Type III
• Open segmental fracture/ extensive soft tissue damage/ traumatic amputation.
∘ All high energy pattern injuries are Type III.
• Special categories in Type III:
∘ Gunshot injuries
∘ Any open fracture caused by a farm injury
∘ Any open fracture with accompanying vascular injury requiring repair.
When was the classification modified?
In 1984, Gustilo et al. subclassified type III injuries:
Type IIIA
• Adequate soft tissue coverage of a fractured bone despite extensive soft tissue laceration
or flaps.
• High energy trauma irrespective of the size of the wound.
Type IIIB
• Extensive soft tissue injury with periosteal stripping and bony exposure.
∘ Usually associated with massive contamination.
Type IIIC
• Open fracture associated with arterial injury requiring repair.
Tell me about the MESS Score.
- Predicts whether lower limb is salvageable.
- Total score ≤6 ~ salvageable limb
- Does not replace experienced clinical judgement, but may aid decision with primary amputation.
A. Skeletal/soft tissue injury
• Low energy (stab, simple fracture, civilian gunshot wound) = 1
• Medium energy (open or multiple fractures, dislocation) = 2
• High energy (close-range shotgun, military gunshot wound, crush injury) = 3
• Very high energy (above+gross contamination, soft tissue avulsion) = 4
B. Limb ischaemia (double the score for >6h)
• Pulse reduced or absent but perfusion normal = 1
• Pulseless, paraesthesias, diminished capillary refill = 2
• Cool, paralysed, insensate, numb = 3
C. Shock
• Systolic blood pressure always >90 mmHg = 0
• Hypotensive transiently = 1
• Persistent hypotension = 2
D. Age (years)
• <30 = 0
• 30-50 = 1
• >50 = 2.
Tell me about the NISSA Score.
- Addresses MESS’s shortcomings (nerve injury, and more detailed about muscle and soft tissue injuries).
- Only open tibial fractures.
- More sensitive and specific than MESS.
Tell me briefly about the AO system and Bastion classification.
AO system
• The most comprehensive soft tissue classification.
• Very complex; reserved for research or coding.
Bastion classification
• Named after Camp Bastion (British military base in Afghanistan).
• Classifies lower limb injuries caused by IEDs.
How are lower limb trauma patients managed initially?
ATLS primary survey
<C>ABC approach <catastrophic> tourniquet may be required (adopted by military).</catastrophic></C>
History
• Mechanism of injury is a guide to the level of energy transferred.
• Factors suggestive of high energy injury:
∘ High speed motor vehicle accidents, particularly pedestrian.
∘ Falls from significant height
∘ Missile wounds
∘ Any injury involving crushing.
Examination
Examination
• Establish the neurovascular status:
∘ Capillary refill time.
∘ Dorsalis pedis and posterior tibial arterial pulse.
∘ Active movement of toes and ankle (common peroneal and tibial nerves).
∘ Sensation on the sole of foot (tibial nerve) and first webspace (deep peroneal nerve).
∘ Re-examine neurovascular status regularly, particularly after fracture manipulation.
• Factors suggestive of high energy injury:
∘ Transverse or segmental fracture pattern with comminution
∘ Associated injuries
∘ Large soft tissue defect
∘ Closed degloving, where skin is intact but perforating vessels are divided.
∘ Tyre prints.
What does the BOA/BAPRAS Standards recommend for initial treatment of lower limb trauma patients?
- Analgesia.
- Restore limb alignment; POP backslab splint.
- Remove gross contamination.
- Photograph wound.
- Cover wound with sterile, saline-moistened gauze covered with semi-occlusive
film dressing. - Repeat neurovascular examination.
- IV antibiotics - co-amoxiclav or cefuroxime 8 hourly:
- Continue until definitive soft tissue cover or 72 hours, whichever is sooner.
- Additional ‘single shot’ gentamicin 1.5 mg/kg at debridement.
- Additional ‘single shot’ gentamicin + teicoplanin/vancomycin at skeletal stabilisation and definitive soft tissue closure.
- Penicillin allergy: clindamycin instead of coamoxiclav/cefuroxime. - Tetanus prophylaxis.
- X-ray - two views, joints above and below fracture.
When should 1st debridement take place?
• UK Standards recommend primary surgery within 24 hours of injury by senior plastic and
orthopaedic surgeons.
• Exceptions mandating immediate surgery:
1. Gross contamination (agricultural, marine, sewage).
2. Compartment syndrome
3. Devascularised limb
4. Another injury requiring immediate surgery.
.
• A major aim of primary surgery is to convert a contaminated traumatic wound into a clean
surgical wound.
• This is achieved by three ‘Es’:
1 Extend
2 Explore
3 Excise.
• Use of a thigh tourniquet is preferred by some surgeons.
Wound extension
• Extend along lines of election for fasciotomy to assess the entire zone of trauma.
∘ Should not injure perforators that supply local fasciocutaneous flaps.
What temporary wound cover measures are there?
• Topical negative pressure dressing
∘ Should not be used instead of definitive vascularised soft tissue cover.
• Antibiotic bead pouch
∘ Polymethylmethacrylate (PMMA) cement impregnated gentamicin or tobramycin covered with semi-occlusive film dressing.
How do you classify degloving injuries?
Avulsion of skin and subcutaneous tissue from underlying muscle or
bone.
• Arnež classified:
∘ Pattern 1 - Limited degloving with abrasion/avulsion
- Typically around bony prominences; may expose bone or joint.
∘ Pattern 2 - Non-circumferential degloving
- Most skin remains as a flap or undermined area, usually just superficial to muscle
fascia.
∘ Pattern 3 - Circumferential single-plane degloving
- More extensive than pattern 2; skin does not usually survive.
∘ Pattern 4 - Circumferential multiplane degloving
- Similar to 3 + breach of muscle fascia.
- Degloving can run between muscles and between muscle and periosteum.
- Indicative of high energy transfer.
• The margins of non-viable skin are difficult to determine:
∘ Fixed staining, thrombosis of subcutaneous veins.
∘ Circumferential degloving.
∘ Poor perfusion (IV fluorescein and Wood’s lamp), indocyanine green (ICG) fluorescence.
How is skin, muscle and bone viability determined?
Skin:
∘ Fixed staining, thrombosis of subcutaneous veins.
∘ Circumferential degloving.
∘ Poor perfusion (IV fluorescein and Wood’s lamp), indocyanine green (ICG) fluorescence.
Muscle viability: four Cs 1 Colour (pink) 2 Contraction 3 Consistency (dead muscle tears easily in the jaws of forceps) 4 Capacity to bleed.
Bone viability: capacity to bleed:
1 Punctate bleeding from exposed cortical surfaces (paprika sign).
2 Extent of periosteal stripping and muscle/fascia connections.
How is debridement and washout performed?
- Deliver ends of fracture out of wound, inspect deep posterior compartment.
- Loose bone fragments that fail ‘tug test’ are removed. Large articular fragments that can be fixed with absolute stability are preserved.
- Following excision, irrigate the wound with large volumes of warm saline.
- Second look 24-48 hours occasionally indicated; multiple serial debridements associated with worse outcomes.
How is provisional and definitive bony fixation achieved?
• Provisional stabilisation: spanning external fixator.
∘ when definitive stabilisation and soft tissue cover cannot be achieved at primary surgery.
∘ pins inserted through ‘safe corridors’ to avoid neurovascular structures.
∘ should allow access to the wound for soft tissue cover.
UK Standards recommend definitive surgery within 72 hours of primary surgery: internal fixation (intramedullary nail, plate, screws).
∘ Internal fixation should not be placed if immediate soft tissue cover cannot be achieved.
How do you manage IIIC injuries?
Vascular injury
• Diagnosed by absent dorsalis pedis or posterior tibial pulse on palpation or Doppler.
• Limb devascularisation requires emergency surgical exploration.
• Muscle suffers irreversible ischaemic damage in 3-4 hours, maximum acceptable delay is 6 hours of warm ischaemia.
• Preoperative angiography unnecessary
• Management of vascular injuries:
- Direct exploration of site of injury.
- Immediate revascularisation by temporary shunts, e.g. Javid, Pruitt-Inahara or Sundt.
- Venous injury at, or proximal to, popliteal vein is also shunted.
- Consider cardiovascular and renal sequelae from toxic metabolites. - Once circulation is restored, reassess limb.
- If salvageable, stabilise skeleton with external fixator.
- Replace shunts with reversed vein grafts.
- Fasciotomy.
Tell me the algorithm for definitive wound cover.
• Vascularised soft tissue.
• UK Standards: senior specialist teams on semi-elective basis within
7 days of injury.
∘ Delay >7 days increases likelihood of friable/fibrotic recipient vessels & infection.
- Local or regional fasciocutaneous and muscle flaps.
or
- Free tissue transfer.
What are the common local and regional FC and muscle flaps used for lower leg reconstruction?
- suitable only for low energy injuries with limited zone of trauma.
Local
- Peroneal or PT artery septocutaneous or myocutaneous perforator flaps
- Proximal tibia: medial sural artery perforator, ALT flap.
- Distal tibia: reverse flow sural neurocutaneous flap
Muscle
- Knee and proximal 1/3: Medial gastrocnemius
- Middle 1/3: Medial hemisoleus, bipedicled tibialis anterior.
What are the pros and cons of FC vs muscle flaps in lower leg reconstruction?
FC: ∘ Aesthetically superior. ∘ Easier to re-elevate for secondary bony reconstruction. ∘ May be sensate. ∘ Minimal donor site morbidity.
Muscle:
∘ Conform better to cavities.
∘ Act as ‘muscle macrophages’, reducing likelihood of infection.
∘ Experimental data demonstrates improved bone healing.
∘ Muscle thins over time to provide a good aesthetic result.
What recipient vessels are suitable in the lower leg?
- Posterior tibial artery
• NVB is between soleus and tibialis posterior.
- Medial approach: between flexor digitorum longus and soleus.
- Posterior approach ‘Godina split’: Posterior mid-calf incision between heads of gastrocnemius and
through soleus. - Anterior tibial artery
• NVB is on interosseous membrane, between tibialis anterior and long toe extensors.
- Approached just lateral to the subcutaneous border of the tibia.
Popliteal and superficial femoral vessels (more proximal).
- Often requires interposition vein grafts.
- Long and short saphenous veins provide additional drainage options if venae comitantes are unsuitable.
- A ‘single vessel leg’ - anastomose end-to-side, and consider reconstructing other injured vessels with vein grafts.
How are segmental bone defects managed?
- Primary bone shortening (max 5cm, otherwise soft tissue and vessels kink, compromising vascularity).
- Temporary placement of a spacer (Masquelet technique)
- Bone grafting
- Primary bone shortening and subsequent lengthening
- bone distraction
- corticotomy and bone transport (and docking)
- Ilizarov, Taylor Spatial Frame (circular). - Reconstruction with vascularised bone (free fibula or DCIA)
