These single plane, intraarticular fractures require anatomical reduction and interfragmentary compression, sufficient to allow early joint motion. The perfection of the articular reduction is usually assessed by an open approach, but where the skills and resources are available, arthroscopically assisted reduction and percutaneous fixation may be considered. The surgeon should be prepared to find additional comminution, not evident until fracture exposure.
Note on approaches
Unless full facilities and expertise for an
are available to check the closed reduction, prior to percutaneous screw insertion, the standard
lateral parapatellar approach
is used to give an optimal view of the joint fracture reduction.
This procedure may be performed with the patient in one of the following positions:
Closed reduction and internal fixation (CRIF) is used in minimally displaced, or undisplaced simple, lateral sagittal, partial articular fractures.
As simple, lateral sagittal, partial articular fractures usually result from a valgus force, the application of a varus stress may reduce the fracture. If varus stress alone is not sufficient, arthroscopy may be helpful.
Temporary K-wire insertion
Under image intensifier control, make a stab incision over the lateral
aspect of the injured condyle and insert a temporary K-wire, to hold the
Make sure, that the K-wire does not conflict with the planned screw
Check of reduction
Check the reduction in two planes using the image intensifier.
In general, the screws are inserted at points along the midshaft axis of the
femur (dashed line). The area distal to the Blumensaat’s intercondylar roof
line must be avoided, in order not to violate the notch. In addition, the area
of the lateral knee recess should be avoided.
If you need to insert a screw in the area distal to the Blumensaat’s
intercondylar roof line, make sure to direct the screw anteriorly, in order to
avoid the intercondylar notch.
Insertion of guide wires
Make a separate stab incision for each screw. Bluntly dissect to the bone,
avoiding the lateral recess of the knee.
Insert the appropriate guide wires for 7.3 mm cannulated screws, or
alternatively 4.5 mm cannulated screws. Depending on the size of the fragment,
2 to 4 screws are necessary.
Correct depth of guide-wire insertion
The depth of guide-wire insertion is crucial. Remember that the cross
section of the distal femoral condylar mass is trapezoidal and slopes markedly
on the medial side. The tip of the guide wire should just engage the medial
cortex, and so will appear short of the medial condylar cortex on the AP
If necessary, internally rotate the femur under AP image intensifier
control, to profile the medial cortex and check for over-penetration.
Screw length determination
Determine the appropriate screw length using the dedicated measuring
Manually insert the screws of appropriate lengths over the guide wires.
Washers may be used. Predrilling is usually not necessary if using
Then remove the temporarily placed K-wire and guide wires.
Illustration showing the completed osteosynthesis.