Commentary & Perspective

Commentary & Perspective on
"Functional Outcome and Complications Following Two Types of Dorsal Plating for Unstable Fractures of the Distal Part of the Radius"
by Tamara D. Rozental, MD, et al.

Commentary & Perspective by
Jesse B. Jupiter, MD*,
Hand and Upper Extremity Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, MA

This study, which was a nonrandomized and retrospective cohort study, presents to the reader several interesting features as well as several areas worthy of discussion.

As the authors point out in the Discussion, the study itself has several limitations. While it does present some outcome data regarding plate fixation of the distal radius and particularly problems of the overlying tendons associated with the Pi plate, the study itself falls short of truly being evidence-based medicine. There is potential bias introduced by surgical preference, nonrandomization, and implant selection, and the very small numbers preclude significant results. The reader is not given much in the way of information as to the surgical technique applied to each type of implant, especially that of the implant associated with the most problems. Were these Pi plates contoured, cut, or left prominent? Were the screws or pegs left prominent from the recessed screws holes?

Does this study provide new information regarding dorsal plating and especially tendon problems associated with the Pi plate? An examination of the text and references identifies that at least five of the eleven references address tendon problems that include tendon inflammation and rupture^1-5. Given that the nine patients who had "low-profile" plates had three different types of plates, including three of one type and one of another type, it would be difficult to assess the Pi plate in comparison with some of these other plates, which may or may not be truly low-profile plates.

There are several explanations for problems with dorsal plating in general and the Pi plate in particular. The Pi plate places the implant on the very distal rim dorsally in an area in which the extensor tendons begin to pass over the radiocarpal joint in a slightly palmar direction. The plate design encourages contouring of the plate and/or the cutting of one or more holes, which can substantially change the surface properties of the metal alloy. The titanium alloy initially used for the Pi plate had surface characteristics that were substantially rougher than that of the stainless steel. The sharper edges of the Pi plate, the adverse changes in surface characteristics created by bending, and the possibility of the screw heads not being recessed in the holes of the implant could all lead to tendon irritation. An attempt was made to smooth the surfaces and change the alloy to minimize these problems. Yet it was clear from the experience presented in this study that tendon problems were found equally with stainless steel and titanium Pi plates.

This study therefore suggests that tendon inflammation is more likely caused by the shape or location of the implant or by the prominent screw heads and/or surface roughness induced by bending and/or cutting the implant than by the metal alloy.

What is remarkable from this study is that despite these apparent difficulties, all of the patients had results that were rated as good to excellent, both from the perspective of the patient and the physician. While there were some differences in wrist motion, the motion was relatively good. The relationship of the extensor tendons to the dorsal aspect of the radius in contrast to that of the palmar surface has led many surgeons to approach even dorsally displaced fractures from the palmar side. Nevertheless, some fractures may not be totally reducible and/or secured effectively from a palmar approach, and therefore dorsal exposure and dorsal implants will remain useful and, in some cases, necessary. The problems that have been identified with larger implants, such as the ones in this report, have led to the concept of fixation of specific aspects of the fracture with very small, strategically placed implants rather than trying to cover the entire distal radius with a single implant. Future studies will likely show less tendon irritation with these newer techniques and implants.

*The author did not receive grants or outside funding in support of his research or preparation of this manuscript. He did not receive 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, educational institution, or other charitable or nonprofit organization with which the author is affiliated or associated.

References

1. Chiang PP, Roach S, Baratz ME. Failure of a retinacular flap to prevent dorsal wrist pain after titanium Pi plate fixation of distal radius fractures. J Hand Surg. [Am] 2002:27:724-8.
2. Lowry KJ, Gainor BJ, Hoskins JS. Extensor tendon rupture secondary to the AO/ASIF titanium distal radius plate without associated plate failure: A case report. Am J Orthop. 2000;29:789-91.
3. Schnur DP, Chang B. Extensor tendon rupture after internal fixation of a distal radius fracture using a dorsally placed AO/ASIF titanium pi plate. Arbeitsgemeinschaft fur Osteosynthesefragen/Association for the Study of Internal Fixation. Ann Plast Surg. 2000;44:564-6.
4. Ring D, Jupiter JB, Brennwald J, Buchler U, Hastings H 2nd. Prospective multicenter trial of a plate for dorsal fixation of distal radius fractures. J Hand Surg. [Am] 1997;22:777-84.
5. Kambouroglou GK, Axelrod TS. Complications of the AO/ASIF titanium distal radius plate system (pi plate) in internal fixation of the distal radius: a brief report. J Hand Surg. [Am] 1998;23:737-41.