Review Question - QID 218828

The use of a locked lateral plate and a separate medial plate (dual plating) provides the greatest axial stability of any choice listed.

Distal femur fractures most commonly occur as low-energy injuries in elderly, osteoporotic individuals. Most are treated operatively in order to re-establish length, alignment, and rotation, and in cases of intercondylar involvement, to restore the joint surface. Operative intervention may consist of lateral locked plating alone, retrograde intramedullary nailing, a combination of lateral plating and nailing, or dual plating. Several studies have examined the biomechanics of distal femur fixation and have noted that dual plating offers the greatest degree of axial and torsional stiffness compared to these other combinations. In practice, there is still some concern that constructs with too much stiffness may contribute to high rates of distal femur nonunion (>15%). This said, it is important to ensure bony stability and understanding the biomechanics of distal femur fixation can help to balance both of these goals.

Rollick et al. studied the effects of dual plating on distal femur vascularity and noted a mean blood flow reduction of 21% in the lateral plating group and 25% in the dual plating group, which was not statistically different. They concluded that most of the vascular insult was caused by the lateral plate and not the addition of the medial plate, which can be placed in a relatively minimally invasive fashion.

Fontenot et al. reviewed the biomechanical effects of lateral locked plating supplementation for distal femur fractures. They noted that adding a medial 3.5mm reconstruction plate or retrograde nail to a classic locked lateral plate increased stiffness significantly. They concluded that the combination of these constructs would increase resistance to cyclical failure and survivability of implants to allow for fracture healing.

Incorrect Answers:
Answer 1: A locked lateral titanium plate would provide less stiffness than a stainless steel plate and certainly less axial stiffness than dual plating.
Answer 2: Locked lateral stainless steel plating would be stiffer than titanium plating, but not as stiff as dual plating. The use of far cortical locking screws is thought to provide some motion at the near cortex to stimulate healing and prevent nonunion from excessive stiffness.
Answer 3: A medial plate alone is not typically sufficient as the tension side of the fracture is not addressed.
Answer 4: A retrograde intramedullary nail alone would provide less axial stability than dual plating techniques. The combination of a retrograde nail and lateral locked plate may be an alternative to dual plating to increase stiffness compared to a conventional lateral plate alone.