There is a concern regarding bridge plating of simple oblique or transverse fractures. These fractures are generally treated by compression plating techniques (ORIF). In the end, however, the surgeon chooses between the advantages of compression afforded by an open approach and the advantages of a minimally invasive osteosynthesis, without optimal compression at the fracture site.
Bridge plate insertion
Bridge plates can be inserted either with an open exposure that respects soft-tissue attachments to the fracture, or using a minimally invasive (MIO) approach that leaves the soft tissues intact over the fracture site. In this latter case, incisions are made proximally and distally, and the plate is inserted through a submuscular tunnel. This requires image intensifier monitoring.
Consideration must be given to fracture reduction in:
- internal/external rotation
Reduction can be performed with a single reduction tool (e.g., large
distractor), or by combining several steps (for example fracture table +/-
external fixator, +/- reduction via the implant, etc.) to achieve the final
The preferred method depends on the fracture and soft-tissue injury pattern,
the chosen stabilization device and the experience and skills of the
If a large fragment has separated from the fracture zone and impaled the
adjacent muscle, direct reduction of that fragment may be required.
Anatomy of the distal femur
The distal femur has a unique anatomical shape. Seen from an end-on view,
the lateral surface has a 10° inclination from the vertical, while the medial
surface has a 20–25° slope. A line drawn from the anterior aspect of the
lateral femoral condyle to the anterior aspect of the medial femoral condyle
(patellofemoral inclination) slopes approximately 10°. These anatomical details
are important when inserting screws, or blade plates. In order to avoid joint
penetration, these devices should be placed parallel to both the patellofemoral
and femorotibial joints planes.
The muscle attachments to the distal femur are responsible for the typical
displacement of the distal articular block following a supracondylar fracture,
namely shortening with varus and extension deformity. Shortening is due to the
pull of the quadriceps and hamstring muscles, while the varus and extension
deformity is caused by the unopposed pull of the adductors and gastrocnemius,
The popliteal vessels, the tibial nerve and the common peroneal nerve lie in
close proximity to the posterior aspect of the distal femur. Because of this,
vascular injuries occur in about 3% and nerve injuries in about 1% of fractures
of the distal femur.
There are no significant arteries, veins, or nerves on the lateral side of
There may be bleeding from the lateral genicular arteries, which will need
to be controlled using diathermy.
At the posterior aspect of the knee lie the popliteal artery, nerve and
vein. It must be borne in mind that these structures can be damaged by the
injury, or can be damaged by the surgeon during the reconstruction.
It is very important to restore the biomechanical axis of the lower limb.
The normal biomechanical axis follows a line from the center of the femoral
head, through the center of the proximal tibia and then through the center of
the ankle joint. This axis can be checked intraoperatively by using a piece of
cable, such as the diathermy cord, to give an approximate estimate of the axis,
The biomechanical axis must be restored and care should be taken to ensure
that there is no malrotation of the distal femur on the proximal femur.
If no traction table is used (i.e., using the freehand technique) the cable
method may be used. In this technique, the electrocautery cord is held from the
iliac spine across the patella to the cleft between the first and second toes.
If rotation is correct, this cord will pass over the midline of the patella,
and slightly medial to the tibial eminence.
The radiological landmarks of the center of the femoral head, the center of
the knee and the center of the ankle joint should all be in line if the
mechanical axis of the femur is correct.
Another method of assessing rotational reduction is to compare the cortical
thickness above and below the fracture. If a shaft fracture is
multifragmentary, the image intensifier cannot be used to compare cortical
diameters on each side of the fracture.
This illustration shows the longitudinal axes of the lower limb.
Choice of implant
For retrograde femoral nailing to achieve adequate fracture stabilization,
the fracture should be at least 6 cm from the joint line to achieve distal
locking with two transverse screws or a screw and a spiral blade. In contrast,
more distal fixation can be achieved with plates, or locked fixators. For
example the distal most screws in a LISS plate, or a condylar plate, may be
The distal-most fixation for various implants are:
- LISS plate: subchondral
- Condylar plate: subchondral
- 95° angled blade plate: 1.5 – 2 cm
- 95° dynamic condylar screws: 2 cm
- Retrograde intramedullary nail: 6 cm (for 2 locking screws, or one locking
screw and a spiral blade)
This procedure may be performed with the patient in one of the following positions:
For this procedure a
minimally invasive (MIO) approach
Preparation for correct positioning
Determine the correct position for the DCS with the help of guide wires
around the joint. Under image intensifier control, pass one guide wire lateral
to medial along the tibio-femoral joint line (red). Pass a second guide wire
over the anterior surface of the knee to indicate the plane of the
patello-femoral condyles (green).
The ideal position of the DCS is shown by the yellow wire. Note that it is
inserted parallel to both the red wire in the frontal plane and is parallel to
the green line on the end-on view on the femur. This latter orientation ensures
that the plate comes to lie flush with the lateral cortex.
The ideal entry point for the DCS is shown on the diagram. The guide wire
for the DCS is positioned at 2 cm proximal to the distal end of femur. On the
lateral view, the distal femur is divided into thirds and the DCS entry site is
located at the junction of the anterior and middle thirds.
Insert the guide wire at the chosen entry site of the DCS. Insert the guide
wire under image intensifier control all the way across the femur. Check the
position of the guide wire carefully to ensure it has been correctly
positioned, with the parallelism already described.
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
Pitfall: too long a guide wire
It is important to remember that the distal femur tapers from the posterior
to the anterior. Therefore, if a straight AP view is obtained, the guide wire
can appear to be inside the bone. If it appears to be outside the bone, it is
most likely too long and the DCS will cause pain and possibly heterotopic
ossification. In order to assess the exact length of the guide wire obtain an
AP view with 30° internal rotation of the lower extremity.
In this illustration, internal rotation by 30° reveals that the guide wire
length was chosen inappropriately.
Screw length measurement
Next, slide the direct measuring device over the guide wire and determine
guide-wire insertion depth and, thereby, the length of the DCS required.
After assembling the DCS triple reamer and setting the reamer to the correct
depth, ream the hole for the DCS over the guide wire.
Preliminary DCS insertion
After tapping, insert the DCS over the guide wire so that its outer end is still visible 2-3 mm outside the lateral cortex of the distal femur. Align the T-handle with the vertical axis of the distal femoral articular block.
Pearl: do not tap the track in osteoporotic bone
Do not tap the track of the DCS in osteoporotic bone.
Detach the T-handle and slide in the plate submuscularly from distal to
The plate is pushed from distal to proximal along the naturally preexisting
potential tunnel beneath the vastus lateralis. If there is a continuous contact
of the plate tip with the bone while pushing it proximally, there is no need
preliminarily to create a tunnel.
Plate and screw combination
Insert the T-handle through the barrel of the plate and reconnect it to the
screw. This can be challenging and may temporarily tilt the distal femoral
articular block. It may be helpful to make an incision over the proximal end of
the plate at this point to gain control of both ends of the plate. This will
allow for easier connection of the plate to the screw.
In order for the barrel to slide over the screw the T-handle should be
parallel, on the lateral view, to the long axis of the distal fragment.
Final plate impaction
Disconnect the T-handle from the screw.
Use the impactor to bring the plate down to the bone with the barrel sliding
over the screw shank.
The compression screw may be used to couple the DCS to the plate.
A cancellous screw can then be inserted into the most distal screw hole of
the plate to prevent rotation of the main distal fragment around the axis of
Pearl: do not use compression screw in osteoporotic patients
Do not use the compression screw in osteoporotic patients – it can cause
the DCS thread to strip out from the soft cancellous bone of the medial femoral
Closed reduction is aided by:
- Complete anesthetic muscle relaxation of the patient
- A bolster posterior to the supracondylar region to prevent
- Manual traction
- Use of the femoral distractor, or external fixator
- Percutaneous instruments (e.g., colinear clamp as illustrated)
Verification of reduction
Under image intensifier control, the preliminary reduction is checked again
with respect to axial alignment, length and, to a degree, rotation.
Insertion of first screw into proximal fragment
Make stab incisions over the proximal fragment according to the planned
final screw placement.
Control the mid-lateral plate position using two blunt Hohmann retractors
placed ventrally and dorsally around the femoral shaft.
If the overall reduction is found to be satisfactory, insert the first
cortical screw in the distal part of the proximal main fragment, without fully
tightening. This still allows for the plate position to be finely tuned.
Pearl: final reduction
If the lateral position prior to the insertion of the second screw is
inadequate, use sterile bolsters to aid correction.
Be cautious not to malalign the articular block as this will make
application of the plate to the proximal femur difficult.
Insertion of second screw into proximal fragment
Confirm the mid-lateral plate position using two Hohmann retractors
introduced through a second incision over the proximal plate portion, or by
Once the most proximal screw is fully inserted, the more distal screw in the
proximal fragment is finally tightened.
According to preoperative planning, insert additional screws into the distal and proximal main fragments. In oblique, single-plane fractures, an interfragmentary lag screw should be inserted through the plate.