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.