We would like to thank Dr. Lovisetti and colleagues for their letter regarding our publication evaluating the performance of a polyaxial locked plate for complex knee trauma. We agree that long standing hip to ankle radiographs are generally more accurate in determining limb alignment after bicondylar tibial plateau fractures. We also agree that diaphyseal translation can influence limb alignment.

We chose to measure the alignment of tibial fractures utilizing a line drawn parallel to the tibial joint line and one perpendicular to the tibial shaft to compare pre and post operative alignment. This method avoided the additional expense (and radiation) of full length films, and we felt that it was adequate to compare alignment CHANGE and to evaluate for varus drift. The comminuted tibial plateau case we chose for a figure was selected because of its highly comminuted meta-diaphysis and the presence of interference screws which necessitated angulation of the locking screws to gain medial purchase. The case also demonstrated indirect reduction and excellent healing despite the high energy nature of the injury.

We concede that this can be considered a minor malalignment due to some shaft translation. It is not angular, but nevertheless, some shift in limb axis would be inevitable. Nevertheless, the take home point of the study was the fact that no CHANGE in alignment occurred due to bushing failure and that polyaxial technology appears to strong enough to manage such complex fractures.

To The Editor:

We read with great interest the article "Results of Polyaxial Locked -Plate Fixation of Periarticular Fractures of the Knee"(1). In the Results section, the authors reported that "No fractures were seen to be malaligned on the postoperative radiographs, and only two demonstrated malalignment at the time of the last follow up". In support of their statement, they presented radiographic images of a bicondylar tibial plateau fracture (Fig.3 A to E) described as "demonstrating excellent alignment" and "fracture healing without loss of reduction". However, we believe the images show a small but real lateral shift of the diaphysis with consequent valgus malalignment.

The authors defined a malalignment as an angulation greater than 5° in any plane, and measured tibial alignment by lines drawn along the tibial shaft and parallel to the tibial articular surface. This method may be inaccurate when there are compression fractures of the articular surfaces that can make the articular line less evident (as with the lateral tibial plateau of the case presented). It also does not take into account the malalignment resulting from translation of the tibial shaft. We believe that lower limb alignment can be better assessed using bilateral panoramic x-rays of the entire lower extremities.

The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.

Reference:

1. Haidukewych G, Sems SA, Huebner D, Horwitz D, Levy B. Results of polyaxial locked-plate fixation of periarticular fractures of the knee. J Bone Joint Surg Am 2007;89:614-620.