KEY NOTES CHAPTER 6: LOWER LIMB - Trauma.

Question 0

What lower limb fracture classifications are you aware of?

Answer 0

∘ 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).

Question 1

What Gustilo type fracture is most common?

Answer 1

60% Gustilo III, of which 60% is IIIB.

Annual incidence 5 per 100,000.

Question 2

Tell me about the Gustilo and Anderson Classification.

Answer 2

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.

Question 3

When was the classification modified?

Answer 3

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.

Question 4

Tell me about the MESS Score.

Answer 4

• 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.

Question 5

Tell me about the NISSA Score.

Answer 5

• 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.

Question 6

Tell me briefly about the AO system and Bastion classification.

Answer 6

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.

Question 7

How are lower limb trauma patients managed initially?

Answer 7

ATLS primary survey

<C>ABC approach <catastrophic> tourniquet may be required (adopted by military).</catastrophic></C>

Question 8

History

Answer 8

• 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.

Question 9

Examination

Answer 9

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.

Question 10

What does the BOA/BAPRAS Standards recommend for initial treatment of lower limb trauma patients?

Answer 10

1. Analgesia.
2. Restore limb alignment; POP backslab splint.
3. Remove gross contamination.
4. Photograph wound.
5. Cover wound with sterile, saline-moistened gauze covered with semi-occlusive
   film dressing.
6. Repeat neurovascular examination.
7. 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.
8. Tetanus prophylaxis.
9. X-ray - two views, joints above and below fracture.

Question 11

When should 1st debridement take place?

Answer 11

• 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.

Question 12

.

Answer 12

• 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.

Question 13

What temporary wound cover measures are there?

Answer 13

• 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.

Question 14

How do you classify degloving injuries?

Answer 14

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.

Question 15

How is skin, muscle and bone viability determined?

Answer 15

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.

Question 16

How is debridement and washout performed?

Answer 16

• 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.

Question 17

How is provisional and definitive bony fixation achieved?

Answer 17

• 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.

Question 18

How do you manage IIIC injuries?

Answer 18

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:

1. Direct exploration of site of injury.
2. 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.
3. Once circulation is restored, reassess limb.
4. If salvageable, stabilise skeleton with external fixator.
5. Replace shunts with reversed vein grafts.
6. Fasciotomy.

Question 19

Tell me the algorithm for definitive wound cover.

Answer 19

• 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.

1. Local or regional fasciocutaneous and muscle flaps.

or

2. Free tissue transfer.

Question 20

What are the common local and regional FC and muscle flaps used for lower leg reconstruction?

Answer 20

• 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.

Question 21

What are the pros and cons of FC vs muscle flaps in lower leg reconstruction?

Answer 21

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.

Question 22

What recipient vessels are suitable in the lower leg?

Answer 22

1. 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.
2. 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.

Question 23

How are segmental bone defects managed?

Answer 23

1. Primary bone shortening (max 5cm, otherwise soft tissue and vessels kink, compromising vascularity).
2. Temporary placement of a spacer (Masquelet technique)
3. Bone grafting
4. Primary bone shortening and subsequent lengthening
   - bone distraction
   - corticotomy and bone transport (and docking)
   - Ilizarov, Taylor Spatial Frame (circular).
5. Reconstruction with vascularised bone (free fibula or DCIA)

Question 24

What is acute compartment syndrome?

Answer 24

Elevation of interstitial pressure in a closed osseofascial compartment that results in microvascular compromise. - surgical emergency: missed diagnosis leads to irreversible neuromuscular ischaemia and significant morbidity.

Question 25

What are the causes of compartment syndrome?

Answer 25

``` ∘ Fractures, (closed and open) ∘ Soft tissue trauma ∘ Arterial injury ∘ Prolonged limb compression in an obtunded patient ∘ Burns. ```

Question 26

What is the pathophysiology of compartment syndrome?

Answer 26

* tissue injury causes increased tissue pressure. * When tissue pressure exceeds capillary pressure, capillary blood flow decreases. * Causes hypoxia and local tissue necrosis. • Capillary pressure is governed by Starling forces, which include: ∘ Capillary and interstitial hydrostatic pressure ∘ Capillary and interstitial oncotic pressure. • Capillary hydrostatic pressure varies from individual to individual. ∘ Typical values: 35mmHg at the arteriolar side; 15mmHg at the venular end of the capillary. - Compartment syndrome therefore occurs well below arterial blood pressure.

Question 27

.

Answer 27

* Pain out of proportion to that expected from the injury. * Pain with passive motion of muscles passing through the compartment. * Paraesthesia or numbness * Tightness * Weakness. * Absent peripheral pulses is a late sign

Question 28

In what cases, can compartment syndrome not be excluded clinically?

Answer 28

∘ Multiple injuries ∘ Impaired consciousness ∘ After regional anaesthesia or peripheral nerve injury ∘ Young age. Compartment pressures should therefore be measured.

Question 29

Measurement of compartment pressures.

Answer 29

• A needle is inserted into the muscle compartment and connected to: - Stryker® Intracompartmental Pressure Monitor System, or - Arterial line set-up. • Compartments should be decompressed if the pressure remains: ∘ >30mmHg ∘ ≤30mmHg below diastolic blood pressure.

Question 30

Draw a cross-section of the leg and the double fasciotomy incision technique.

Answer 30

.

Question 31

How do you perform lower leg fasciotomies?

Answer 31

1 Two skin incisions: ∘ Medial longitudinal incision 1-2 cm posterior to medial tibial border. ∘ Lateral longitudinal incision 2 cm lateral to anterior tibial border. 2 Both posterior compartments are decompressed through a medial incision. ∘ Posterior tibial NVB is at risk during decompression of deep posterior compartment. ∘ The tibial attachment of soleus is released to access the proximal part of the deep posterior compartment. 3 Anterior and peroneal compartments are decompressed through a lateral incision. ∘ Subfascial dissection proceeds laterally to anterior intermuscular septum 'Poke test' - A finger is inserted subfascially and 'poked' medially - hitting tibia confirms anterior compartment has been entered. The finger is then poked posteriorly - hitting fibula confirms anterior intermuscular septum has been opened.

Question 32

When is amputation indicated?

Answer 32

1 Immediately, for life saving damage control surgery. - After multi-level vascular injury and haemorrhage following ballistic trauma. - After crush injuries with warm ischaemia >6 hours. - military paradigm: radical debridement, without closure of stump to preserve as much length of viable tissue as possible. - Definitive closure 48-72 hours later. 2 Early, when limb salvage is either impossible or would give a suboptimal result. - Incomplete traumatic amputation with an injured distal remnant. - Avascular limb with warm ischaemia 4-6 hours. - Segmental muscle loss affecting >2 compartments. - Segmental bone loss >1∕3 length of tibia. - Severe open foot injury. 3 Late, after failed limb salvage with a stiff, useless, painful limb.

Question 33

Limb salvage versus primary amputation

Answer 33

Lower Extremity Assessment Project (LEAP): multicentre study of severe lower limb trauma in US civilians. No difference in functional outcome between patients who underwent either limb salvage surgery or primary amputation. Decision to amputate should involve at least two Consultant surgeons, patient and family. Absent or altered plantar sensation is not a good predictor of long-term function. Physiological, psychological and socioeconomic factors are also considered.

Question 34

How can osteomyelitis be classified?

Answer 34

Inflammation of bone caused by an infecting organism. Duration ∘ Acute < 2 weeks ∘ Subacute - 2 weeks to 1 month ∘ Chronic > 1 month. ``` Mechanism of infection - Exogenous ∘ Open fracture ∘ Surgery ∘ Local soft tissue infection - Haematogenous ∘ Bacteraemia. ``` Host response • Pyogenic • Non-pyogenic.

Question 35

What is the difference between acute and chronic OM?

Answer 35

Acute OM - affects children through haematogenous spread of organisms. Chronic OM - dead bone with infected foci surrounded by sclerotic avascular bone, thickened periosteum, scarred muscle and subcutaneous tissue (hard for iv antibiotics to penetrate).

Question 36

How is chronic OM classified?

Answer 36

Anatomical type • I: Medullary - endosteal disease • II: Superficial - cortical surface infected due to coverage defect • III: Localised - cortical sequestrum, excisable without causing instability • IV: Diffuse - Features of types I, II and III with mechanical instability before or after debridement.

Question 37

How is OM classified physiologically?

Answer 37

Physiological class • A: Normal • B: Compromised - local or systemic factors compromising immunity or healing • C: Prohibitive - minimal disability, prohibitive morbidity anticipated, poor prognosis for cure.

Question 38

What investigations are used to diagnose OM?

Answer 38

Clinical, laboratory and imaging data. • Bone biopsy (gold standard) for histological and microbiological analysis. • Plain X-rays: cortical destruction, periosteal reaction. • Sinograms • CT and MRI

Question 39

How is chronic OM managed?

Answer 39

``` Within MDT setting: ∘ Orthopaedic surgeons ∘ Plastic surgeons ∘ Infectious diseases specialists ∘ Microbiologists. ``` Combination of curative surgery and long-term antibiotics, with the goal of eradication of infection by achieving a viable and vascular environment. ∘ Simple versus complex treatment ∘ Curative versus palliative treatment ∘ Limb sparing versus limb ablation.

Question 40

Tell me about the treatment of chronic OM.

Answer 40

1 Debridement of affected bone and soft tissues +/- circular frame. 2 Dead space management - Import vascularised soft tissue, usually a free flap, or - Papineau technique: open bone grafting: • Debridement + daily moist dressings until granulation tissue is present throughout wound. • The bony cavity is then filled with strips of autogenous cancellous bone graft. • The exposed wound and bone graft are covered with moist, antibiotic-impregnated gauze. • Modified technique: negative pressure wound therapy. • When the bone graft is overgrown with granulation tissue, the wound is skin grafted.