Measurement of Optimal Insertion Angle for Iliosacral Screw Fixation Using Three-Dimensional Computed Tomography Scans.

BACKGROUND: Percutaneous iliosacral screw fixation can provide stable fixation with a minimally invasive surgical technique for unstable posterior pelvic ring injuries. This surgical technique is not limited by cases of difficult fracture patterns, sacral dysplasia, and small sacral pedicles that can occur in Asians. The purpose of this study was to investigate the incidence of the sacral dysplasia in the Korean population and determine the optimal direction of iliosacral screws by analyzing pelvic three-dimensional computed tomography (3D-CT) scans. METHODS: One hundred adult patients who had pelvic 3D-CT scans were evaluated. The upper sacral morphology was classified into three groups, i.e., normal, transitional, and dysplastic groups; the cross-sectional area of the safe zone was measured in each group. S1 pedicle with a short width of more than 11 mm was defined as safe pedicle. The incidences of safe pedicles at different angles ranging from 0° to 15° were investigated in order to determine optimal angle for screw direction. RESULTS: The incidence of normal, transitional, and dysplastic group was 46%, 32%, and 22%, respectively. There were significant increases of the cross-sectional area of the safe zones by increasing the angles from 0° to 15° in all groups. The incidence of safe pedicles increased similar to the changes in cross-sectional area. The overall incidence of safe pedicles was highest at the 10° tilt angle. CONCLUSIONS: The incidence of sacral dysplasia in Koreans was 54%, which is higher than previous studies for Western populations. The cross-sectional area of the safe zone can be increased by anteromedial direction of the iliosacral screw. Considering the diversity of sacral morphology present in the Korean population, a tilt angle of 10° may be the safest angle.

Streptococcus dysgalactiae subspecies dysgalactiae infection after total knee arthroplasty: a case report.

Streptococcus dysgalactiae subspecies dysgalactiae (SDSD), Lancefield group C streptococcus, is an animal pathogen which often causes pyogenic infection in domestic animals. Human infection by SDSD has been reported as a cellulitis on the upper arm, but a prosthetic joint infection caused by SDSD after total knee arthroplasty (TKA) has not yet been reported in the literature demonstrating that its clinical manifestation and management have not been well established. In this case report, we aimed to present a case of SDSD prosthetic joint infection after TKA, which was successfully treated by two-stage re-implantation with an application of antibiotic-impregnated cement spacer.