Distal Femur(Sandeep Sir)

8/17/2019 Distal Femur(Sandeep Sir)

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Distal femur Fractures-

Plating pearls and pitfallsDr Sandeep GuptaAssistant Professor

G.M.C.H , Chandigarh



Biomechanics of distal femur

Factors under the surgeon's control :

• implant metallurgy

• screws ( locking/non locking,uni/bicortical)

• plate length

• screw hole fill

Cortical slotting techniques or far cortical locking screws :

• decrease construct stiffness

• create more uniform callous formation

Distal most screw in the diaphyseal segment is most important

• dictates working length

• dictates stiffness of the implant



Recommendation

• Use a long plate(8-10 holes in proximal fragment)

• Staggered fixation in proximal frag. with 50%

holes filled is enough

• Screw near to fracture in prox. fragment preferablybe cortical(helps as reducing agent and

decreases stiffness)

• optimise distal fixation with proper platepositioning and proper screw orientation



Role of medial plate

• Generally should not be used in acute fracture

• Has a role in management of delayed /non-

union of fractures with medial comminution



Potential pitfalls

Almost all are because of incorrect plate placement

Can be described by the “Rule of Too’s”:

• too valgus

• too anterior

• too rotated

• too distal

• too flexed or extended

• too far off bone.



Potential pitfall-1

• Fracture alignment that is too

valgus

• Results in coronal planedeformity of the articular

surface

• Easily preventable (as modern

plates are designed toreproduce the anatomic lateral

distal femoral angle of 81° to

85°)



Pitfall-2

Plate placed too anterior either proximally

on the diaphysis or distally on the condyles

• Leads to compromised fixation leading to

failure, because eccentrically placed screws

Plate applied too anterior near the knee

• Painful encroachment on the extensor

mechanism

• Screw placement into the patellofemoral joint

Plate applied too posterior distally

• screws into the intercondylar notch causing

injury to the cruciate ligaments and knee

motion limitation



Pitfall-3

Plate applied too distal

• intra-articular screw placementinto the intercondylar notch or

patellofemoral joint

• painful implant prominence(iliotibial band syndrome)

• the “golf club” deformity canresult as the plate convexityabuts the condyles, effectivelymedializing the entire articularblock.



Pitfall-4

Plate applied too rotated

• rotational deformity

• screws may be aimed into

unintended areas anteriorly or

posteriorly around the knee



Pitfall-5

Plate applied too flexed or too

extended

• lead to compromised fixation

• prominent hardware

• sagittal plane (curvatum)

fracture deformity



Pitfall - 6

Plate applied too far off the

bone

• may cause symptoms as a

result of implant prominence

under the iliotibial band

• may be associated withmalediction increased risk of

implant failure.



Tips to optimise plating

• Avoidance of implant-related problems is largely

preventable

• Important to understand the local anatomy, the

implants and how they are designed to be used

• Thorough preoperative planning

• Computed tomography scan of the distal femur

(so as not to miss occult hoffas fracture)



TIP -1Understand the Relevant Anatomy and Its

Radiographic Appearance

• Articular surfaces of the medial and lateral

condyles coalesce to form the trochlea

anteriorly

• Trochlea's subchondral arc is well seen on

lateral radiographic images

• Posteriorly intercondylar fossa houses the

ACL & PCL

• Blumensaat's line on lateral imagingrepresents the anterior and proximal limit of

the intercondylar notch

• Medial condyle extends distally than its

lateral counterpart, resulting in a valgus

limb axis (94° and 100°)



TIP - 2

Shape of the distal

femur is trapezoidal

• angle of inclination ofthe medial surface ~25

• lateral surface of the

condylar segment isinternally rotated relative

to the sagittal plane by

approximately 10°



TIP - 3Use plate design to recreate

anatomy

• distal locking screws are

inserted with a vector parallelto the distal femoral condyles

• proximal shaft of the plate is

apposed to the femoral

diaphysis

• result is coronal plane

fracture alignment of 5° to 8°

of valgus



TIP - 4

Quality Radiography and Interpretation of Images

• Optimal intraoperative imaging with C-arm fluoroscopy and

radiographic interpretation is mandatory

• Optimal AP can be achieved by obtaining a quality AP image of

the knee (where the fibula is partly overlying the tibia) and the

patella centered over the condyles

• Optimal lateral view is obtained by superimposing the femoralcondyles on one another

• The “notch” view can demonstrate screws that cross the

intercondylar notch



TIP - 5

Enough emphasis cannot be placed on theimportance of fracture reduction

• formal arthrotomy to adequately visualize thearticular surface for reduction and fixation ofcomplex articular injuries

• the universal femoral distractor (or external fixator,if present) is useful for restoring length, sagittalplane reduction and maintains the reductionduring plate application



TIP - 6

Plate Positioning

• Centered along midlateral line and appliedwithin a centimeter of the vermillion border(anterior edge) of the lateral condylar surface

• Plate should match the lateral contour of thesupracondylar flare and end at a point 1 or1.5 cm above the joint line(AP view)

• Joint axis wire should be close to parallelwith the articular line of the femoral condyles

• Plate well centered distally with the distalscrew cluster near but not beyond theradiographic junction of Blumensaat's lineand the subchondral margin of the trochlea



TIP - 7Accurate Joint Axis Pin or ScrewPlacement Is Essential

• cannulated wire guide is appliedthrough the joint axis reference hole

• pin should be parallel to the joint axisof the distal femoral condyles on a APimage

• lateral view, pin will be seen as aimedslightly posteriorly (eg, 10–20°) and

distal (6°)

• Sagittal alignment of the condylesrelative to the shaft is often bestassessed on a lateral image using thealignment along the posterior cortex



TIP - 8

• Optimal AP and lateralimages of the distalfemur should be

obtained beforeleaving the operatingroom

• Oblique views and thenotch view may behelpful, as outlinedpreviously



Conclusion

• major complications with plate and screw fixationof distal femur fractures are underappreciated

• use of anatomically contoured plating systemspresents a risk for fracture malreduction andimplant-related problems if not applied improperly

• use of current surgical technique and avoidanceof the pitfalls discussed can minimize implant-related complications and improve patientoutcomes



THANK YOU

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Distal Femur(Sandeep Sir)