Background: Locked-plate fracture-fixation techniques and designs
continue to evolve. Polyaxial locking plates that allow screw angulation and
end-point locking have become available; however, there are no clinical data
documenting their strength and efficacy, to our knowledge. The purpose of this
study was to evaluate the clinical performance of a variable-axis locking
plate in a multicenter series of periarticular fractures about the knee.
Methods: Between 2003 and 2005, fifty-four patients with a total of
fifty-six fractures were treated with a polyaxial locked-plate fixation system
(DePuy, Warsaw, Indiana). There were twenty male patients and thirty-four
female patients with a mean age of fifty-seven years. There were twenty-five
distal femoral fractures and thirty-one proximal tibial fractures. Twelve of
the fractures were open. Clinical and radiographic data, including changes in
alignment, hardware breakage, or other mechanical complications of the device,
were retrospectively reviewed. Function was assessed with use of the Knee
Society scores. One patient with a bilateral fracture died less than three
months postoperatively, and two patients were lost to follow-up prior to
union. Fifty-two fractures in fifty-one patients were followed to union or for
a minimum of six months; the mean duration of follow-up was nine months
(range, six to twenty-five months).
Results: Forty-nine (94%) of the fifty-two fractures united. There
were no mechanical complications. Most importantly, there was no evidence of
varus collapse as a result of polyaxial screw failure. There were three deep
infections and one aseptic nonunion. No plate fractured, and no screw cut
Conclusions: The variable-axis locking plates performed well, with a
high rate of fracture union and no evidence of varus collapse due to failure
of the polyaxial screw fixation, in a series of complex fractures about the
knee. Complication rates were similar to those for historical controls treated
with fixed-trajectory locking plates. Polyaxial locking plates offer more
fixation versatility without an apparent increase in mechanical complications
or loss of reduction.
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors for a complete description of levels of evidence.