Less Invasive Stabilization System (LISS) for Distal Femur Fracture Repair

Pre-procedural planning

Template to determine plate length and preferred screw position. Plan for at least four screws to be placed in the intact shaft proximal to the fracture.

Anesthesia

After the operative leg has been marked, anesthesia is induced and the patient is brought to the operating room.

Positioning

• The patient is positioned supine on a radiolucent table.
• A bump ipsilateral to the injury under the buttock may be necessary.
• The knee should be supported, and the injured leg should move freely.
• Ensure that a lateral radiographic view of the femur is possible.

Exposure

1. Mark Incision
2. Incision and Dissection
   1. A Lateral incision is made from Gerdy’s tubercle extending approximately 8 cm proximally.
   2. Note: For a complex intra-articular fracture a lateral parapatellar approach may be used.

Reduction

3. Clamp Reduction
   1. Extra-articular reduction is performed indirectly with either an external fixator, distractor, traction, or other means.
   2. Ensure that length, rotation, varus-valgus, and recurvatum reduction is adequate.
4. K-Wire Stabilization
   1. K-Wires are used in this case to maintain the reduction.
   2. Note: Lag screws may be used to reduce the articular surface. These screws should be placed so as to avoid the planned location of the LISS plate and locking screws. If necessary, these lag screws may be placed medially to laterally.
5. Evaluate/Adjust Reduction

LISS

6. Plate Insertion
   1. Assemble the insertion guide
   2. Screw the fixation bolt into the LISS plate and tighten with a pin wrench. Then screw the nut on the fixation bolt and tighten with the pin wrench. A stabilization bolt in an adjacent hole may be used if desired.
   3. The plate is inserted distally to proximally in the space between the periosteum and the vastus lateralis.
   4. The proximal end of the plate should remain in contact with bone throughout insertion. The distal end of the plate should be against the lateral condyle. Slide the plate proximally and distally to identify the optimal placement on the lateral condyle.
   5. The insertion guide will be internally rotated 10^o to the femoral shaft when sitting properly on the lateral condyle.
7. Provisional Fixation with K-Wires
   1. Take a lateral view of the femoral diaphysis to ensure that the screw holes along the proximal end of the plate are aligned with the center of the medullary canal.
   2. Using the insertion sleeve with a 5.0 mm trocar, mark and make an incision at the most proximal hole on the plate.
   3. Use the guide to put the insertion sleeve and trocar through the incision and secure the sleeve by tightening the nut on the guide.
   4. Replace the trocar with the stabilization bolt and thread into the proximal plate hole.
   5. Insert a 2.0 mm K-wire through the stabilization bolt. Confirm plate position and fracture reduction.
8. Fix Alignment Proximally
9. Use Whirlybird Pull-Reduction Device
   1. Additional minor reduction corrections can be performed at this time using the pull reduction instrument if desired.

Locking Screw Insertion

10. Distal Fixation
    1. Use insertion sleeve and trocar in the guide to mark for stab incision, then perform stab incision at the distal locking screw sites.
    2. At least four screws should be inserted into each main fracture fragment.
    3. Use the guide to put the insertion sleeve and trocar through the incision.
    4. Remove the trocar, then insert a 5.0 mm locking screw under high-speed power and complete tightening by hand with the torque-limiting screwdriver.
    5. A K-wire and measuring device may be used to confirm appropriate screw length.
    6. Use stoppers to mark screw location on the guide after screws have been inserted.
11. Proximal Fixation
    1. Insert the diaphyseal screws after all distal locking screws have been inserted.
    2. Ensure that the screw holes are centered over the medullary canal.
    3. To insert the screw that will replace the proximal stabilization bolt: first remove the K-wire, then remove the stabilization bolt. Insert a 5.0 mm locking screw without applying pressure to the insertion guide.
12. Continue Fixation Distally then Proximally
13. Replace Guide Handle with Final Screw
    1. If planning to use Hole A, this must be the last screw inserted. Place stabilization bolts with insertion sleeves in two adjacent open holes. Remove the K-wire, then the fixation bolt. Insert a 5.0 mm locking screw.

Closure

14. Assess Stability
15. Confirm Final Position of Implants
16. Irrigation and Closure

Postoperative Protocol

• The patient is awakened from general anesthesia and brought to the post-anesthesia care unit.
• Patient is discharged from the hospital on postoperative day three.
• The patient is made touch down weight bearing.
• Postoperative follow-up visits are scheduled for one month.
• Range of motion and physical therapy are scheduled before follow-up visit. Patient to remain in knee immobilizer outside of physical therapy.