Session I - Tibia

The Less Invasive Stabilization System for the Treatment of Complex Fractures of the Proximal Tibia

James P. Stannard, MD; Timothy C. Wilson, MD; David A. Volgas, MD; Jorge E. Alonso, MD, University of Alabama at Birmingham, Birmingham, AL

Purpose: The Less Invasive Stabilization System (LISS) is a set of anatomically pre-shaped plates developed for stabilization of distal femur and proximal tibia fractures. The LISS plates feature percutaneously placed unicortical screws, pre-shaped plates, and threaded screw holes and screw heads that yield a fixed-angle implant with each screw placed. This paper provides a preliminary report of the use of the LISS plates in the treatment of high-energy tibia-plateau and proximal tibia fractures with use of minimally invasive techniques.

Methods: Forty-eight patients (38 men and 10 women, average age 39 years) with 52 fractures of the proximal tibia or plateau were prospectively treated with LISS plates. Thirty-one fractures involved the tibial plateau with three classified as Schatzker V and 28 classified as Schatzker VI fractures. All 31 tibial plateau fractures were classified as 41C in the OTA classification. The mechanism of injury included 28 motor vehicle accidents, 9 falls, 4 pedestrian versus motor vehicle accidents, 4 nonunions, 2 gunshot wounds, 2 assaults, and 1 crush injury. The average Injury Severity Score was 15 with a range of 4 to 41. Twenty patients had multiple fractures and 17 had ipsilateral extremity fractures. Twenty-one knees had major ligament injuries. Forty-five patients had acute fractures; 31 of these involved the tibial plateau. Eighteen were open fractures, including 2 Grade I, 10 Grade IIIA, and 6 Grade IIIB.

Results: Forty-four of the acute fractures in this series healed, and one patient had a nonunion. The mean follow-up in our series was 12.2 months. The average time for achieving radiographic callus was 6.6 weeks, and the average time to complete union was 16.9 weeks. The postoperative alignment was anatomic in all but four patients. One patient had a valgus alignment of 5° and three patients had procurvatum of less than 10°. The average joint step-off was 0.9 mm, with a range of 0 to 3 mm. The range of motion average was 2° to 116°. Two patients (3.8% of the fractures) developed deep infections, both occurring in Grade-IIIB open fractures. The incidence of infection after open fractures was 11%, and the incidence after Grade-III open fractures was 12.5%.

Discussion: High-energy tibial plateau fractures represent a complex fracture type with a high complication rate reported in the orthopaedic literature. Problems include loss of knee motion, infection, soft tissue breakdown, and loss of reduction or fixation. The LISS system provides a minimally invasive plating technique that features a fixed-angle construct that maintains alignment without the use of a medial plate. We had no cases of postoperative malalignment or loss of fixation. Proximal tibia fractures are often difficult to maintain in alignment when they are treated with an intramedullary nail. The LISS system allows treatment of these fractures with a limited approach and soft tissue dissection without the problems of loss of alignment. We used the LISS plates on open tibia fractures despite the known high risk of infection with conventional plates. The LISS system can be placed with minimal soft tissue stripping and does not compress the periosteum, behaving more like an "internal external fixator." Although infections did occur in our series, the incidence was no higher than that commonly reported with external fixation despite an overwhelming majority of Grade III fractures among our patients.

Conclusion: The tibial LISS-plating technique worked well to stabilize difficult fractures of the tibial plateau and proximal tibia with a low incidence of complications in our series of patients. Stabilization of most bicondylar tibial plateau fractures can be successfully accomplished without the addition of a medial plate. The LISS system functioned well in open fractures, with an incidence of deep infections no higher than that commonly reported with external fixation.