WHAT ARE SOME UNIQUE FEATURES OF LOWER EXTREMITY RECONSTRUCTION?
- Full body weight is transmitted through the legs and ankle:
- must withstand stress and gravitational forces
- is sensate, padded, and stable
- Greater incidence of vascular disease
- atherosclerosis
- Venous stasis, edema, thrombosis 2’ high hydrostatic pressure imposed on LE
- Longer time (distance) for nerve regeneration
- Multi-disciplinary - orthopedics, vascular surgery, plastic surgery + allied health
how is the tibia connected to the fibula?
- proximally, tibiofibular joint
- distally, tibiofibular syndesmosis
- intermediate: interosseous membrane
Describe the anatomy of the anterior compartment of lower leg
- 4 muscles: tibialis anterior, extensor hallucus longus, extensor digitorum longus, peroneus tertius
- actions: all dorsiflex the foot. TA also inverts whereas PT everts. EHL extends great toe and EDL extends other toes
- innervation: deep peroneal n
- arterial supply: muscular branches from anterior tibial artery.
- TA: type IV. EHL and EDL
- Artery travels:
- originates from politeal artery at it’s lower border
- crosses btwn 2 heads of TP to enter anterior compartment
- proximal 1/3 travels on IO membrane btwn TA and EHL
- middle 1/3 travels on IO membrane btwn TA and EDL
- lower 1/3 travels on anterior surface of tibia, btwn EHL and 2nd toe EDL; runs under extensor retinaculum to become superficial as dorsalis pedis artery
- Nerve travels:
- originates as common peroneal n
- bifurcates around head of fibula
- runs on fibula for short distance (3-4cm) before crossing IM septum to enter anterior compartment (from lateral compartment)
- runs under EHL on anterior surface of IO membrane
- initially is lateral to anterior tibial artery, then as approaches ankle it runs superficial to medial side
describe the anatomy of the lateral compartment of the lower leg
- muscles include peroneus longus and peroneus brevis
- action: both evert and plantar flex the foot
- innervation: superficial peroneal n
- arterial supply: PL - muscular branches from ATA and peroneal a; PB just muscular branches from peroneal a
- the superficial peroneal nerve travels between PL and PB
describe the contents of the superficial posterior compartment of lower leg
- muscles
- gastrocnemius - plantarflexion of foot and flexion of knee
- tibial nerve
- medial and lateral sural arteries (from popliteal, type I)
- soleus - plantarflexion foot
- tibial nerve
- muscular branches from posterior tibial and peroneal, and sural arteries
- plantaris - weak plantarflexion; excellent for tendon graft
- tibial nerve
- sural arteries (from politeal)
- popliteus - flexes knee and rotates tibia
- tibial nerve
- genicular brancehs of popliteal artery
- gastrocnemius - plantarflexion of foot and flexion of knee
describe the contents of the deep posteiror compartment of the lower leg
- muscles:
- tibialis posterior - plantar flexion
- tibial nerve
- muscle branches of peroneal a
- flexor hallucus longus - great toe flexion, plantar flexion
- tibial nerve
- muscular branches of peroneal a
- flexor digitorum longus - 2nd - 5th toe flexion, plantar flexion
- tibial nerve
- muscular branches of posterior tibial artery
- tibialis posterior - plantar flexion
- course of posterior tibial artery - travels w tibial nerve
- deep to deep investing fascia/solus
- initially on tibialis posterior, then on FDL,
- lower 1/3 becomes more superficial, runs medial to tendo-calcaneous, nearly on tibia, then crosses joint
- the tibial nerve is intially medial, then runs deep and lateral to artery
- at medial malleolus - Tom, Dick, And Now Harry
- Tib Post
- Flexor Digitorum longus
- Artery - posterior tib
- Nerve - tibial
- Flexor Hallucus longus
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what is the risk of compartment syndrome wiht open tibial fracture?
6-9%
What is the Gustillo Classification? Describe it.
Why is it used?
- Gustillo classification was originally intended to classify open tibial fractures, although now it has extended in context to describe open fractures of long bones in other parts of the body
- it’s original purpose was to help describe treatment and salvage
- Grade 1: simple fracture, skin clean, laceration < 1cm
- Grade 2: open fracture, wound > 1cm, without extensive damage
- Grade 3:
- higher velocity injury, segmental fracture, comminution, EXTENSIVE SOFT TISSUE DAMAGE: including, devitalization or contamination,
- 3A: extensive soft tissue injury, but sufficient viable tissue for bone coverage
- 3B: with periosteal stripping and bone exposure, insufficient for bone coverage
- 3C: any open tibial fracture with arterial injury requiring repair
What are the limitations of the Gustillo classification?
- does not sufficiently quantify the extent of soft tissue or bone damage
- does not differentiate between ambiguity of leg wiht arterial injury while maintaining sengle vessel run-off
- does not accurately classify patients to salvage vs. amputation
Describe history for lower extremity traumatic wound
- after ATLS
HPI
- ID: age, occupation, hobbies
- other associated injuries, their treatments, prognosis
- mechanism: high vs. low energy, twist/rotational forces vs compression forces vs tangential forces
- initial ability to ambulate, noted changes to gait, sensation etc
- initial first aid provided
PMHx/SOC Hx/MEDS/ALL/smoking status
- all especially DM, CAD, PVD, history of VTE
- baseline gait and weight bearing, use of assistant devices
Any goals or expectations of management
Describe comprehensive examinations for mangled lower extremity
ATLS first
- Assessment for limb viability: examine wound, vascular, soft tissue, skeletal, nerve injuries
- vascular: palpable DP or PT pulse, colour, CR temperature, turgor of foot, bedside doppler
- for a stable patient with gustillo grade III (at least IIIB +) angiogram for lower extremity vascular assessment
- skeletal injury: visible bone in wound, mandatory XR evaluation: open/closed; simple/segmental/comminuted; displacement/angulation
- also direct visualization (typically in OR at 1st wash) for extent of periosteal stripping, viability of bone segments
- soft tissue: status and viability of skin, SC tissue, muscle, periosteum
- avulsion, crush, viability, etc
- initial assessment in ED; best assessed in OR during debridement
- neurologic
- motor exam: anterior compartment muscles (deep peroneal); lateral compartment (superficial peroneal); deep compartments (tibial)
- sensory exam: dorsal foot (sup peroneal), dorstal 1st web (deep peroneal), plantar surface (medially and laterally, tibial nerve to medial and lateral plantar nerves); lateral malleolus (sural nerve)
- vascular: palpable DP or PT pulse, colour, CR temperature, turgor of foot, bedside doppler
what is the overarching goal of lower extremity reconstruction?
- To reconstruct a limb that is more functional than if it were to be amputated
- If limb-salvage is not feasible, the goal becomes to preserve sufficient length for a below-knee prosthesis
what are the 3 most common isolates in lower extremity osteomyelitis?
1) Staph aureus
2) Pseudomonas
3) Anaerobes
what are the major advances in lower extremity reconstruction through history?
- Immobilization
- Antibiotics
- Debridement and delayed closure (WWII)
- Vascular repair (vs. ligation)
- Soft tissue coverage with regional flaps then microsurgery
- Management of bone gaps with vascularized bone or distraction osteogenesis
- VAC
- Perforator flaps
Describe your thought process when making a reconstructive plan for lower extremity trauma
- Is there a vascular injury?
- Quick access to high quality angio vs. on-table angiography
- If vascular and skeletal injury, consider temporary vascular shunts if completely devascularized lower extremity and warm ischemia time approaching 4-6 hours
- Skeletal stabilization - options
- Casting, traction - uncommon, temporizing, closed
- External fixation - preferred method for initial presentation; no additional periosteal/endosteal stripping or soft-tissue disruption; allows access to wound for additional debridements and eventual coverage
- Internal fixation
- intramedullary rod - requires immediate ST coverage; endo-osteal stripping; minimally comminuted and minimal bone loss; allows for early ambulation
- plate - requires immediate ST coverage; significant foreign body; significant periosteal/soft-tissue stripping
- Definitive vascular repairs
- 4-compartment Fasciotomy for every case of vascular repair; for most open fracture or crush injury patients
- Debridement of non-viable tissue and debris
- Vital structures NOT exposed, incomplete debridement of further delineation of zone of injury expected
- plan for second/third debridement
- Vital structures ARE exposed
- complete debridbement of all evident and anticipated non-viable tissue
- immediate coverage
- complete debridbement of all evident and anticipated non-viable tissue
- Definitive soft tissue coverage - principle should be generally within 1 week of injury; should be immediately at placement of internal hardware
- When should VAC be considered
- within first week prior to definitive coverage
- may be more useful for small wounds to help avoid operation for soft-tissue cover
when do you consider getting a CT angiogram during lower extremity trauma
- massive / severely mangled injuries
- identified or suspected ischemic injury
- injuries that will require soft tissue reconstruction
Discuss considerations of nerve injury for lower extremity injury
- prognosis for re-innervation is poor
- long distance from injury to motor end plate
- large zone of injury necessitating long nerve grafts
- motor end plate atrophy
- peroneal nerve injury - in general loss of dorsiflexion (foot drop) & sensation on dorsum
- sensory loss tolerated well
- motor loss managed w/ splinting or tendon transfers
- tibial nerve injury - in general loss of plantar flexion & sensation on plantar
- loss of plantar flexion significantly impairs ambulation (loss of push-off), would consider joint fusion
- loss of plantar sension impairs gait, evolve to charcot arthropathy, prone to occult injury - similar to diabetic foot neuropathy
- reconstruction with tibial nerve injury is guarded but not contra-indicated
Discuss considerations in management of bone gaps in lower extremity trauma
- Available methods
- Non-vascularized bone graft
- Small gaps < “few” (?4) cm when there is a well-vascularized and stable bed
- Distraction osteogenesis (Iliazarov technique)
- Gaps 4-8cm
- Obliterate gap w/ graft, then distract after union at fraccture site achieved
- Vs. fill gap w/ non-vascularized cancellous graft, then distract proximal or distal segment to the gap
- Vascularized bone graft
- Gaps > 8 < 24cm
- Best choice is fibula for this indication
- In theory ipsilateral pedicle may be available; otherwise contralateral free
- length of fibula - 12cm is available for reconstruction; could split & fold in 1/2
- Non-vascularized bone graft
- Timing of repair
- Immediate bone gap repair with definitive soft tissue coverage
- Wound control, definitive soft tissue coverage with placement of antibiotic beads, wound bed allowed to mature, delayed bone gap management
- Preferred approach
for mangled lower extremity injuries, what is one factor that promotes use of free tissue transfer compared to use of local fasciocutaneous or muscle flaps?
- Local flaps remain in zone of injury
what are the principles of treatment once osteomyelitis has been established after lower extremity trauma?
- debridement of all devitalized soft tissue and bone
- reconstruction of defect with healthy, well vascularized tissue
- placement of antibiotic beads
- external fixation
- systemic antibiotics
- delayed definitive management of bone gap
Why do we emphasize preservation of length even when we are going to amputate during lower extremity truama?
- BKA has elevated energy expenditure and oxygen consumption compared to non-amputee, but AKA is significantly greater than BKA
- BKA can walk longer distances
- AKA are less likely walk at all, may require motorized transport/chair
what is the ideal length of preserved tibia for BKA?
- > 6cm below the tibial tubercle
List the muscles in each layer of the foot
- Dorsum: EDB
- Plantar:
- 1st level: AbdH, FDB, AbdDMB
- 2nd level: quatratus plantaris, lumbricals
- 3rd level: FHB, AddH, FDMB
- 4th level: plantar and dorsal interosseous
what branches does the tibial nerve give to the foot?
- medical calcaneal (sensory only)
- medial and lateral plantar (sensory and motor)
What are the contents and boundaries of the femoral triangle?
- boundaries:
- lateral - sartorius
- medial - adductor longus
- superior - inguinal ligament
- floor: pectineus, iliopsoas, other adductors (brevis, magnus)
- contents
- Within femoral sheath, from medial to lateral:
- Femoral vein, Femoral artery, Lymph nodes (of Cloquet)
- Lateral to femoral sheath is greater saphenous vein (draining into femoral vein)
- Femoral nerve (most lateral)
What is Hunter’s canal? How is it related to femoral triangle? What enters/exits?
- Hunter’s canal is adductor hiatus / canal through adductor magnus
- Allows for femoral artery to move from anterior to posterior (otherwise would have significant traction w/ knee bending)
- Sheath of canal is inferior extension of femoral sheath (from wihtin femoral triangle)
- Permits the femoral artery (SFA), femoral vein and saphenous nerve
what are the specific reconstructive goals for lower extremity reconstruction?
- debride all devitalized tissue and debris & obtain healthy wound bed
- restore vascular integrity
- restore skeletal stability
- provide stable, durable, well-vascularized soft tissue coverage of bone, nerve, vessels, tendons, internal hardware
- obliterate dead space and provide contour over 3D anatomy
- provide a functional lower extremity for bipedal ambulation
- maintain acceptable aesthetics
- minimize donor site morbidity
How do you classify lower extremity defects?
- By etiology
- Congenital
- Acquired (majority)
- Trauma - subclassify by mechanism: low/high velocity; compression/lateral/torsion/crush; open/closed
- Tumour - benign, malignant, metastatic; tissue involved by tumour
- Infection - soft tissue, osteomyelitis
- Ischemic - vascular insufficiency (arterial, venous); compartment syndrome
- Iatrogenic - surgical (dehiscence, exposed vital structures), radiation
- Endocrine - diabetic foot or lower extremity wonds
- By sub-site on extremity
- By tissue involved
What are the phases of open fracture?
- acute - inflamed - day 1-5
- subacute - colonized +/- infected - day 5 to week 6
- chronic - infection of scar, sequestrum - > 6 wks
what are some specific systemic coplications of open tibial / lower extremity fracture
- hemorrhage
- fat embolism
- venous thromboembolism
- rhabdomyelitis
- compartment syndrome
List absolute and relative contraindications to limb salvage in mangled lower extremity trauma
- Absolute
- warm ischemia > 6 hrs
- gustillo 3C + severe life threatening injuries
- significant morbidity or other ongoing severe life threatening injury/polytrauma
- multi-level injury
- segmental tibial loss > 8cm
- Relative
- transection tibial nerve in adult
- severe ipsilateral foot trauma
- anticipated protracted (>1yr) course of soft tissue and bone management
What factors do you consider when choosing and planning for the reconstruction?
- Wound
- size, site, tissue components
- adjacent planned/previous infection or radiation
- zone of injury
- foreign body / implant planned/present
- associated neurovascular injury
- Host factors - comorbidities
- Functional outcome
- Aesthetic outcome
- Planned recipient vessel and required pedicle length
- Anticipated future 2’ary procedures
What factors influence your decision to choose a fasciocutaneous vs. muscle free flap in lower extremity reconstruction?
- Muscle
- dead space
- 3D contour
- more bulk (perhaps)
- Fasciocutaneous
- anticipated 2ary procedures
- avoidance of skin graft / aesthetic outcome
- less donor site morbidity
- cutaneous sensation
What are options and considerations for coverage of groin wounds?
- Considerations:
- need to determine which vessels are available or are not available based on regional anatomy, vascular (bypass) grafts, occluded/ligated vessels
- Options
- free tissue transfer rarely required
- small wound: sartorius myoplasty (transpose w/ or w/o division of 1-2 (3) perforators - note periosteal origin counts as 1)
- ipsilateral femoral vessels intact:
- muscle (+/- skin or STSG): TFL, VL, RF, gracilis
- FC: ALT, groin (SCIA)
- ipsilateral femoral vessels absent, ispilateral external iliac intact
- muscle (+/- skin or STSG): rectus abdominus/VRAM
- FC: Ruben’s flap (w/ cuff of EO/IO/TA)
- ipsilateral femoral and external iliac unavailable: contralateral VRAM (tram) vs free tissue transfer
What are options for thigh reconstruction
- depends on site (medial, lateral, anterior, posterior) and whether tere are any exposed vital structures
- usually can use local tissue / muscle
- TFL, ALT/VL, rectus femoris, gracilis, posteiror thigh flap, biceps/hamstrings
- regional tissue/muscle
- rectus abdominus/VRAM
what are options and considerations for segmental femur defects?
- > 12cm
- free fibula - can be double-barrel or wihtin an allograft
- 6-12cm
- free fibula > iliac crest (has a natural curvature, significant donor morbidity)
- < 6cm
- free fibula > iliac crest > scapula
What are options for coverage of the knee?
- Medial gastroc
- Lateral gastroc
- proximally based soleus
- free tissue transfer
- (theoretically reverse ALT on anastomosis w/ superior genicular, never seen, don’t say)
What are options for coverage of proximal 1/3 of lower leg?
What is #1 preference?
Local muscle (w STSG)
- Medial gastroc - #1 choice
- Lateral gastroc
- Proximal (hemi) soleus
- bipedicle tibialis anterior (small defect of tibia)
Local fasciocutaneous
- saphenous flap
- antegrade sural artery flap
- posterior calf flap (descending cutaneous flap off branch of poplital a)
What are options for coverage of middle 1/3 of lower leg defects? What is your #1 choice?
Muscle (w STSG)
- proximally based hemi-soleus #1 option
- medial > lateral gastroc
- bipedicle tibialis anterior (small central tibial defect, partial harvest)
- FHL (often taken w soleus to supplement that flap)
- EDL or EHL (small defects, significant morbidity)
Fasciocutaneous
- Ponten flap
- propellor flap
List reconstructive options for distal 1/3 leg (not ankle, foot)
- generally or historically thought to require free tissue transfer, due to lack of reliable local options
- for larger defects with significant exposed vital structures (vessels, nerves, bones, internal hardware) choose free tissue transfer
- options
- mid-sized defect, FC options: lateral arm, radial forearm, parascapular (scapular)
- mid-sized defect, muscule options: gracilis
- large-sized defect, FC options: ALT
- large-sized defect, muscle options: LD, rectus abdominus
- options
- local options include, but be sure vessel intact and not significantly in ZOI:
- PTA intact: PTA perforator flap, medial plantar artery flap
- ATA intact: dorsalis pedis flap, EDB flap
- PA intact: lateral supramalleolar flap, reverse sural flap (posterior defects)
- PA & PTA intact: reverse hemi-soleus, lateral supramalleolar flap
list local reconstructive options for medial and lateral malleoli
- medial malleolus
- ATA intact: dorsalis pedis / 1st DMTA +/- EDB, AbdH
- PTA intact: PT perforator, medial plantar artery flap
- PA intact: reverse sural
- PA & PTA: reverse hemi(medial) soleus
- lateral malleolus
- ATA intact: dorsalis pedis / 1st DMTA +/- EDB
- PTA intact: PT perforator
- PA intact: reverse sural flap, lateral supramalleolar flap, peroneus brevis flap
- PA & PTA: reverse hemi (lateral) soleus
what are local options for heel reconstruction?
- PTA: medial plantar artery flap (best option); can include FDB and medial calcaneal n
- also lateral calcaneal artery flap + sural n.
- PA: reverse sural artery flap (also good option) + sural n.
What are considerations for recipient vessel for free tissue transfer in distal 1/3 and foot free flaps?
- pre-operative angiogram to determine # / patency of vessels feeding the foot
- if 1 or 2 vessel foot consider End-to-Side
- if distal: choose PTA as 1st choice because calibre, superficial but protected location behind medial malleolus
- ATA prone to kinking or compression w ankle movement when chosen distally
- more proximally, outside ZOI, choose vessel that is closest to desired position of inset
- know to find ATA ~ 1cm lateral to tibial crest, between TA and EHL proximally, and between EHL and EDL tendons @ ankle
- know to find PTA in superficial part of deep posterior compartment proximally and distally until ankle (on PT muscle, then on FHL, then essentially on posteromedial tibia ); at ankle between FDL and tibial nerve/FHL
- know that peroneal artery travels deep to fibula, pierces interosseous membrane ~ 5cm proximal to lateral malleolus