Lower Limb Flashcards
what are normal compartment pressures?
0-8mmHg
what compartment pressure would indicate compartment syndrome?
> 30mmHg or within 30mmHg of patients diastolic blood pressure
what is the delta pressure?
Delta pressure = Diastolic BP - intercompartment Pressure
what delta pressure is indicative of compartment syndrome?
<30mmgHg
where do you place the anterolateral incision in a fasciotomy?
2cm lateral to the lateral border of the tibia
where do you place the posteromedial incision in a fasciotomy?
1-2cm medial to the medial border of the tibia
which artery lies in the posterior compartment?
Posterior tibial a
which nerve lies in the superficial posterior compartment?
Sural Nerve
which artery lies in the anterior compartment?
Anterior tibial a
which artery lies in the lateral compartment?
Fibula artery
peroneus tertius lies in what compartment?
anterior
the nucleus pulposus makes up which part of the intervertebral disc?
central
helps distribute pressure
what makes up the outer portion of an intervertebral disc?
annulus fibrosus
multiple laminae of fibrocartilage - withstand compressive forces
which peripheral nerves make up the caudal equina?
L2 - S5
which structures are at risk in the anterolateral approach to the hip?
Femoral artery, vein, nerve
what is the inter muscular plane used in the anterolateral approach to the hip?
Tensor fascia lata + gluteus medius
what is the inter muscular plane in the lateral approach to the hip?
Gluteus medius + vastus lateralis
what structures are at risk in the lateral approach to the hip?
Femoral n
superior gluteal nerve
what is the inter muscular plane used in the posterior approach to the hip?
Gluteus maximus along its fibres
which structures are at risk in the posterior approach to the hip?
sciatic nerve
inferior gluteal nerve
superior gluteal nerve + artery
Femoral vessels
which structures are at risk in the lateral approach to the ankle?
Sural nerve
Superficial peroneal nerve
short saphenous vein
where does the superficial peroneal nerve cross from the lateral to anterior compartment of the leg?
10cm proximal to tip of fibula
what position should the patient be in for anterolateral approach to the hip?
Lateral Decubitus Position
where is the incision for the anterolateral approach to the hip?
2.5 distal and posterior to ASIS - centred over GT - over proximal shaft of femur
which structures are at risk in the direct lateral approach to the hip?
Superior gluteal nerve
Femoral nerve
where does the superior gluteal nerve run in relation to the greater trochanter?
3-5cm above GT
what is the inter muscular plane in the direct lateral approach to the hip?
Split of Gluteus Medius distal to innervation
Split of Vastus laterals lateral to innervation
in what position would you splint a dislocated knee after relocation?
Above knee backstab in 30 degrees flexion to control for rotation
what are the boundaries of the popliteal fossa?
Superolateral - biceps femoris
Superomedial - semitendinosus, semimembranosus
Inferolateral/inferomedial - gastrocnemius
floor - popliteus, back of knee
roof - skin and fascia
what is the most common knee dislocation?
anterior
what is the most common nerve injury in knee dislocation?
common peroneal nerve
what classification is used in knee dislocation?
Kennedy
what is the kennedy classification based on?
Direction of displacement
what is the schenck classification based upon in knee dislocation?
ligamentous injury
what classification system is used in tibial plateau fractures?
Schatzker classification
what is a type I schatzker tibial plateau fracture?
Lateral split
what is a type II schatzker tibial plateau fracture?
Lateral split depression
what is a type III schatzker tibial plateau fracture?
Lateral pure depression
what is a type IV schatzker tibial plateau fracture?
Medial plateau fracture
what is a type V schatzker tibial plateau fracture?
BIcondylar fracture
what is a type VI schatzker tibial plateau fracture?
metaphysical-diaphyseal dissociation
what drill size is used in a large fragment set? (cortical screws)
3.2
what screw size is used in a large fragment set? (cortical screws)
4.5
what drill size is used in a small fragment set? (cortical)
2.5
what screw size is used in a small fragment set? (cortical)
3.5
conservative management can be considered in what type of tibial plateau fractures?
Minimally displaced split or depressed fractures
what is the main complication of tibial plateau fractures?
Post traumatic arthritis
what is the definition of an open fracture?
Fracture which has direct communication to the external environment
what is a gustilo anderson type IIIc open fracture?
any open fracture with VASCULAR INJURY requiring repair
what is a gustilo anderson type I open fracture?
Wound <1cm
minimal contamination
minimal soft tissue damage
simple fracture pattern
what is a gustilo anderson type II open fracture?
Laceration >1cm (but <10cm)
moderate soft tissue damage
simple fracture pattern
minimal contamination
what is a gustilo anderson type IIIb open fracture?
IIIa + Periosteal stripping + bone exposure
requiring soft tissue coverage
what is a gustilo anderson type IIIa open fracture?
Laceration >10cm
Extensive soft tissue damage
segmental fracture
heavily contaminated wounds
patients with open fractures of long bones should be managed where?
specialist centre with orthoplastics care
what dressing should be used on initial assessment of open fractures?
Saline soaked gauze
occlusive dressing
within what time frame should antibiotics be given in open fractures?
1 hour
in which circumstances should immediate debridement of an open fracture take place?
- highly contaminated wounds (farmyard, sewage, aquatic)
- associated vascular compromised
in which circumstances should debridement of an open fracture take place within 12 hours?
high energy open fractures
in which circumstances should debridement of an open fracture take place within 24 hours?
low energy open fractures
in what time frame should definitive soft tissue coverage or closure be achieved in open fractures?
Within 72 hours
what antibiotics should be used in open fractures initially?
Coamoxiclav or cephalosporin
*clindamycin/teicoplaning if severe allergy
what antibiotics should be added at initial debridement for open fractures?
Gentamicin
how long should Abx should be continued after debridement for open fractures?
24 hrs
what antibiotics should be added at time of fixation for open fractures?
Teicoplanin + Gentamicin
what are the 4 Cs to identify muscle necrosis?
Colour
Contractility
Consistency
Capacity to bleed
what test is used to identify healthy bone at time of debridement?
Tug test
what is the exception to removing bone that fails the tug test?
Articular fragments which can be fixed with absolute stability
what are the nerve roots of the sciatic nerve?
L4-S3
where does the sciatic nerve bifurcate?
apex of popliteal fossa
where does the sciatic nerve travel in relation to piriformis muscle?
below piriformis (90% of cases)
what muscles does the sciatic nerve supply in the thigh?
Hamstrings - semimembranosus, semitendinosus, hamstring portion of adductor magnus
what muscles does the superficial peroneal nerve supply?
lateral compartment of leg - fibularis longus + brevis
what muscles does the deep peroneal nerve supply?
anterior compartment of leg - tib ant, EDL, EHL, PT
where does the superficial peroneal nerve supply sensation?
lateral leg + dorsum of foot
where does the deep peroneal nerve supply sensation?
lateral leg and 1st webspace
where does the tibial nerve supply sensation?
sole of foot + posterior leg
what muscles does the tibial nerve supply?
Superficial and deep compartment of posterior leg
what basic maneouvres are used in relocation of dislocated hip?
Traction
Countertraction
Knee flexed
internal rotation
in a native hip what investigation must be performed after dislocation?
CT hip
from what plexus does the sciatic nerve originate?
lumbosacral plexus
where does the sciatic nerve enter the thigh?
By passing deep to long head of biceps femoris
how does the sciatic nerve leave the pelvis?
Greater sciatic foramen
which nerve is most commonly injured in a knee dislocation?
Common peroneal nerve
after reduction of knee dislocation what immobolisation is recommended?
Knee splint or above knee backslab in 20 degrees flexion
what are the x ray signs of an ACL tear?
Segond fracture
Anterior tibial translation
what are the x ray signs of an ACL tear?
Segond fracture
Anterior tibial translation
what are the attachments of the ACL?
origin - anterior intercondylar area, blends with medial meniscus
insertion - lateral femoral condyle
what are the attachments of the PCL?
origin - posterior intercondylar fossa
insertion - medial femoral condyle
what are the 2 major branches of the femoral artery?
Superficial Femoral Artery
Profunda femoral artery
what are the 2 major branches of the femoral artery?
Superficial Femoral Artery
Profunda femoral artery
where can the femoral artery be palpated?
mid inguinal point - 1/2 way between ASIS and pubic symphysis
which artery travels through the adductor canal?
popliteal artery
what are the 2 major branches of the popliteal artery?
Anterior tibial artery
Tibioperoneal trunk
the posterior tibial artery travels behind which structure?
medial malleolus
the anterior tibial artery becomes which artery in the foot?
dorsalis pedis
a common peroneal palsy will present with what signs?
Foot drop + loss of eversion
what structures are in the popliteal fossa?
Tibial nerve
popliteal vein
Popliteal artery
in what percentage of subtalar dislocations are occult talus fractures present?
44%
what are the 3 main blood supply to the talus?
Posterior tibial artery (body)
Anterior tibial artery
Perforating peroneal artery via artery of tarsal sinus
the talus is at high risk of AVN because of what?
retrograde blood supply
what 3 joints articulate with the talus?
Subtalar (talus + calcaneum)
Tibiotalar
Talonavicular
what classification system is used in talus fractures?
Hawkins
the prescence of subchondral lucency seen 2 months after a fracture indicating reperfusion of the talus - describes what sign?
Hawkins sign
what is the average diameter of a lag screw used in DHS?
12.5mm
what tip apex distance should be aimed for in intertrochanteric fractures?
<25mm
what is the size of the guidewire used in DHS?
2.5mm
what is the definition of tip apex distance?
Summation of distance between apex of screw and apex of femoral head on AP and lateral radiographs
what is the definition of a subtrochanteric fracture?
upto 5cm below the trochanters
what classification system is used for intertrochanteric fractures?
Evans
what classification system is used for subtrochanteric fractures?
Russel Taylor
what number classification is hip fractures used for in AO?
31 (31A for extracapsular)
where is the anterior attachment for the hip capsule?
Along the intertrochanteric line
where is the posterior attachment for the hip capsule?
more proximal midway along the femoral neck
what 3 ligaments stabilise the hip joint?
iliofemoral
pubofemoral
ischofemoral
what are some associated injuries in calcaneum fractures?
- extension into calcaenocuboid joint
- contralateral calcaneum fractures
- vertebral fractures
what structures can obstruct an ankle from reduction?
Deltoid ligament
periosteum
soft tissues
what is a mortise view?
10 degrees internal rotation
how do you test the syndesmosis?
stress views
bone hook
