Stabilisation of Femoral Fractures Flashcards
Are femoral # often open or closed?
Closed
The incidence of complications with femoral # are higher than other sites; why might this be? (3)
Underestimation of mechanical challenges;
Overaggressive approaches;
Utilisation of inappropriate fixation methods.
What is A concentric axial load?
uniaxial load that is applied through the anatomic axis of bone.
axial loads on the femur are applied how..?
eccentrically
Why is the force on the femur eccentric?
The femoral head is not aligned with the shaft of the femur
What does the femur eccentric force cause?
Bending
What anatomically is located proximal femur? (5)
Head
Neck
Trochanters
Trochanteric fossa
The proximal metaphysis
The cylindrical diaphysis of cortical bone of femur:
A) Where is narrowest diameter?
Proximal third of femur
The cylindrical diaphysis of cortical bone of femur; the distal third of diaphysis is what shape in dogs?
Curves caudally
The cylindrical diaphysis of cortical bone of femur; the diaphysis is what shape in cats?
Straight
What is present distally of the femur? (5)
The distal metaphysis,
Supracondylar region,
Trochlea,
Condyles,
The intercondylar fossa.
Where on the femur lacks muscular attachment?
Diaphysis
What muscles attach to the femur Proximally, subtrochanteric region? (4)
M. vastus lateralis,
M. vastus intermedius,
M. vastus medialis
adductor longus muscle.
What spans the entire length of the caudolateral diaphysis of femur? (2)
Adductor magnus
Brevis muscle
What muscles of the femur attach to Caudomedial surface, distal third, extending onto medial femoral condyle? (2)
M. pectineus,
M. semimembranosus.
Because of the muscle pull, what displacement is common with distal fractures?
Caudo-proximal
What artery of the femur enters the large, principal nutrient foramen in the proximal third and divides into numerous ascending and descending medullary arteries?
Branch of medial circumflex femoral a.
What are the sole blood supply to bone fragments in comminuted or segmental fractures of the femur? Where does it enter?
The periosteal arteries,
Enters: the diaphysis along the facies aspera
What attaches to the facies aspera?
Adductor m
Approximately 25% of the longitudinal length of the femur originates from.?
proximal (capital) physis
What % of the longitudinal length of the femur originates from distal femur?
75
Prior to surgical fixation of femur, what needs to be done? (5)
Shock treatment
Assessment for other injuries
Cage confinement (external coaptation not successful)
Appropriate analgesia
Prompt surgical fixation
Where is a CT scan of the femur particularly useful with femur #? (2) Looking for.. ? (3)
- Proximal
- Distal
E.G with subtle comminution, articular involvement, or with the presence of fissures.
What x ray view is particularly useful for proximal femur?
Frog leg view
Xraying the femur; oblique projections of the distal region of the femur in combination with what 2 xrays may be helpful?
Tangential view of the trochlea,
radiographs centred over the stifle
Diaphyseal femoral fractures can be described how? (7)
Transverse
Short oblique
Long oblique
Spiral
Butterfly
Segmental
Comminuted.
Proximal femoral fractures can be classified into what 3 types?
Intracapsular
Extracapsular
Intertrochanteric
What are the 4 sub # types of intracapsular Proximal femoral fractures?
Epiphyseal
Physeal
Subcapital
Transcervical
What is the sub type of extracapsular Proximal femoral fractures?
Basilar neck
What is the sub type of intertrochanteric Proximal femoral fractures?
Subtrochaneteric
Distal femoral fractures can be categorised how?
Metaphyseal
epiphyseal
Intercondylar
Distal femoral fractures of the metaphyseal can be sub categorised how?
Supracondylar
Distal femoral fractures of the epiphyseal can be sub categorised how?
Condylar
Distal femoral fractures of the intercondylar can be sub categorised how?
Bicondylar (T or Y fractures) usually with supracondylar component
Bone plates are applicable to almost all fractures of which aspect of the femur?
Diaphysis
Which aspect of a femur should a bone plate be applied?
Tension surface - lateral
Bone plate on the femur: For anatomic reconstruction and interfragmentary compression: what is required? (2)
precise contouring of the plate is required;
significant twisting and bending of the plate is required, which can be challenging when using larger size implants.
Placement of an intramedullary rod (IM pin) pin is beneficial in facilitating what in the femur? (2)
Reduction
Restore allignment
IM pins of the femur are placed along what axis of the bone?
Anatomic
Main anatomy to identify for lateral approach to femur? (3)
Greater trochanter
Patella
Outline of femur
Where is incision made on lateral approach to femur?
Cranio lateral aspect of the femur; greater troachnter to patella.
Approach to the latera femur - how to get passed msucles?
NOT TO GO THROUGH
Approach to lateral femur; what is moved caudally?
Caudal - biceps femoralis
Approach to lateral femur; what is moved cranially?
Vastus lateralis m
How to improve bone exposure on lateral approach to femur?
Periosteal elevator
The adductor magnus brevis inserts along the linea aspera. What is the linea aspera?
Distinctive ride along caudo lateral aspect of femur
Which of the following is NOT recognised as a predisposing factor in the development of contracture of the quadriceps femoris muscle following open stabilisation of a femoral fracture?
Being a skeletally mature dog
Muscular trauma
Extended period of coaptation
Exuberant bony callus
Skeletally mature
What is the advantage of NOT disturbing the linea aspera on the lateral approach?
Alignment of the #
Items for an IM pin?(4)
Chuck or drill + chuck
Bone holding forcep
Pin cutter
Range of steinmann pins
How to measure IM pin for femur? When is this done?
Distal end of medullar canal to greater troachenter (intra op or contra lateral limb on xray)
IM pin placement in femur; how is proximal segment secured?
Bone holding forceps
Where is an IM pin placed in the femur? How is it then placed/advanced?
Proximal point of greater trochanter
Medial into trochanteric fossa
Low speed ; aim cranial than advance to distal femur. Advance to # site
Reduce # and advance into distal; resistance in distal metaphyseal
Pins can also be placed in a retrograde fashion in the femur how?
Being driven from the fracture site up the proximal bone segment.
How is the hip positioned to place a retrograde pin? why?
his must be done with the hip in extension to avoid damage to the sciatic nerve as it exits the bone.
How to protect soft tissue during IM pin of femur?
Hohmann retractor
IM femur pin placement:
Distraction can be assisted by removing the sharp tip of the pin as it passes through the fracture site. This reduces the risk of..
Inadvertent penetration of the distal cortex at the level of the stifle.
Where to cut IM pin of with the femur? How is this done?
Lie below proximal portion of greater trochanter
Measure length of pin outside femur
Withdraw partially, confirm length to be removed.
Advance into bone
Break at cut
How to confirm IM pin is adequately recessed?
Palpation including soft tissue.
What size intramedullary pin is recommended when combined with a plate for the stabilisation of long bone fractures?
30-40% of medullary canal diameter
Stabilisation of a comminuted diaphyseal # of the femur and applying bridging plate. What is needed? (10)
Drill
Range of bone reduction forceps
2.5mm drill bit
3.5, 2.5 double drill guide
3.5mm DCP drill guide
3.5mm tap (if non tapping screes)
Depth gauge
Screwdriver
Bone plate
Bending plyers.
What is placed before Stabilisation of a comminuted diaphyseal # of the femur and applying bridging plate?
IM pin
Which surface is a bridging plate contoured to the femur?
Lateral
Bridging plate of the femur should lie along what length?
Whole of the length
First drill for bridging plate? Where and how?
Drill through both corticies; proximal
What happens if you hit IM pin when drilling for a bridging plate?
If the drill contacts the intramedullary pin it can be slightly redirected to allow clear passage to the trans cortex. If there is inadequate space a monocortical screw may be necessary.
What is the purpose of a depth gause?
Screw length
How to confirm the alignment of a hole with a bridging plate before screw applied?
K wire
After proximal neutral screw placed; what then is placed
Distal hole - neutral
How to close following bridging plate to femur?
Fascia lata to biceps muscle - continuous
Routine closure - subcut and skin
When applying an DCP as a bridging plate for stabilisation of a comminuted fracture which of the following statements is correct?
Secondary or biological bone healing occurs
Anatomical reduction is achieved
The application of cerclage wire increases the stability of the repair
Apposition of fracture fragments should be near perfect
Secondary or biological bone healing occurs
During open latearl approach to femur:
The origin of vastus lateralis muscle may be elevated from the craniolateral surface of diaphysis for greater exposure of What region?
the subtrochanteric region.
What can the lateral open approach to the femur be combined with to expose the whole femur? (2)
Craniolateral approach to hip joint
A lateral parapatellar approach
Is the gluteal m relatively bigger in dog or cat?
cat
What muscle, not present in dogs is interposed between the superficial gluteal and biceps femoris muscles in cats?
Caudofemoralis m
Place the IM pin normograde in proximal-to-distal direction.
Normograde placement advantages? (4)
Results in more accurate positioning of the rod within the trochanteric fossa and medullary canal.
Reduces manipulation of the fracture site.
Better preserves the fracture hematoma.
Carries a lower risk of sciatic nerve injury, particularly in cats.
During normograde IM pin placement of the femur, how should the A) Femur and B) Hip joint be held?
A) Adduct
B) Maximal extension
Normograde IM pin placement of the femur:
Which region of the trochanteric fossa should the pin stay within?
Craniolateral
Femur IM pin placement:
With the proximal fracture segment stabilised by bone-holding forceps placed along the subtrochanteric region, drive IM pin distally using? (2)
Hand chuck or power drill at low speed
IM pin placement of the femur:
In dogs, what is often necessary to avoid perforation of cranial cortex proximal to the trochlea and stifle joint.
slight overreduction of the distal fracture segment in the sagittal plane
Plate placement with IM pin of femur:
What plate types require contouring? (3)
Standard veterinary cuttable
Dynamic compression,
Lmited-contact dynamic compression plates
Plate placement with IM pin of femur:
A minimum of how many cortices should be engaged within the proximal and distal fracture segments?
4
Plate placement with IM pin of femur:
What plate needs less precise contouring?
Angle-stable plate
Angle stable Plate placement with IM pin of femur:
A minimum of how many cortices should be engaged within each segment?
three (to four)
Based on cray - how do you know if DCP used?
Oval holes
How to recognised LCP on xrays?
recognisable because of the figure-of-8 holes, which are the combi-holes that allow either placement of a cortical screw (neutral or in compression) or placement of a locking screw.
