As with any articular injury, anatomical restoration of the joint surface must be obtained. This is generally best done under direct vision, with clamp application, provisional fixation and then lag screw fixation.
The surgeon must bear in mind that the strong axial loading forces, as well as varus/valgus stress in the knee joint can tend to displace fragments. With vertical fracture lines, in particular, screw fixation alone may not be sufficient, and a buttress plate should be added.
This procedure may be performed with the patient in one of the following positions:
Remove the intraarticular hematoma and rinse the joint thoroughly with
Ringer lactate solution.
First reduce the main fragment using a periosteal elevator and a ball-spiked
pusher (illustrated). Then reposition the smaller fragment using a dental pick.
Take care to reduce it anatomically, to ensure smooth joint surface.
Skin incision for large pointed reduction forceps placement
Make a lateral skin incision for the insertion of a large pointed reduction
Temporary fixation with K-wire insertion
Hold the final reduction using a large pointed reduction forceps. Make sure
not to place the pointed reduction forceps too posteriorly, as compression
across the intercondylar notch would tend to tilt the fragment.
Secure the reduction with one, or more, temporary K-wires. Make sure that
the K-wire does not conflict with the planned screw track.
Option: absorbable pins
Optionally, the small intermediate fragment may first be fixed by absorbable
pins, before final reduction of the main condylar fragment.
Check of reduction
Check the reduction in two planes using image intensifier control.
In general, the screws are inserted at points along the midshaft axis of the
femur (dotted 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 medial knee recess should be avoided.
If you need to insert a screw in the area distal to the Blumensaat’s
intercondylar roof line, direct the screw anteriorly, in order to avoid the
Drill screw hole
Make a small 1.2 cm incision.
Create a pilot hole using a 3.2 mm drill bit in the direction of the
eventual screw insertion.
Determine appropriate screw length
Insert a depth gauge into the hole, to determine the appropriate screw
length. Generally, a screw is chosen which is 5-10 mm short of the lateral
Remove the depth gauge and tap for the 6.5 mm cancellous bone screw under
image intensifier control. In all but the densest cancellous bone of young
athletes, tap only the near fragment – the screw itself will normally create
its own thread in the cancellous bone of the far fragment
Insert the 6.5 mm partially threaded cancellous bone screw and fully
tighten. In the case illustrated, the partially threaded screw will have 32 mm
of thread, as opposed to 16 mm of thread.
Note: a washer may be used, particularly in osteoporotic
Additional screw insertion
Insert 1 or 2 additional screws in a similar manner, and remove the
Irrigate all wounds copiously. Insert an intraarticular suction drain. Close
the joint using absorbable sutures. The use of suction drains in the
extraarticular tissues may be considered. Close the skin and subcutaneous
tissue in the routine manner.