External fixator pin placement during initial management of tibial plateau fractures: are there parameters to minimize pin-plate overlap?

Purpose: External fixator pin site overlap with definitive fixation implants (pin-plate overlap) has been identified as a risk factor for surgical site infection in tibial plateau fractures. Despite this, pin-plate overlap occurs in 24–38% of patients. This study sought to identify radiographic characteristics associated with pin-plate overlap to help minimize occurrences. Methods: 283 patients at two Level I trauma centers were retrospectively reviewed. Radiographic measurements were recorded including fracture length, distance from fracture to proximal tibial pin site, and pin site distance-to-fracture (PSF) ratio. Results: 70 (24.7%) cases of pin-plate overlap were identified. Pin-plate overlap was associated with increased fracture length (81.5 ± 32.1 mm vs 56.9 ± 26.1 mm, p < 0.001) and decreased distance from fracture to proximal tibial pin site (84.5 ± 37.1 mm vs 126.9 ± 35.8 mm). Pins placed greater than 100 mm and 150 mm from the fracture eliminated 36/70 (51%) and 67/70 (96%) pin-plate overlaps, respectively. Pins placed with a PSF ratio greater than 1.5 and 2.0 eliminated 47/70 (67%), and 57/70 (81%) of pin-plate overlaps, respectively. Conclusions: Longer fractures, pins closer to the fracture, and decreased PSF ratio were associated with overlap. Placing proximal tibial pins more than 100 mm from the fracture eliminated most pin-plate overlaps. [ABSTRACT FROM AUTHOR]