Safe Placement of Intramedullary Nail and Inter-Physician Variability in Guidewire Placement in Retrograde...

Retrograde tibiotalocalcaneal arthrodesis is a salvage procedure for severe arthrosis and deformity of both the tibiotalar and subtalar joints and requires image-confirmed placement of a retrograde guidewire. The anatomical shape of the calcaneus creates a situation in which guidewire placement can be skewed on imaging based on the angle of either internal or external rotation. As a result, the aims of our study were to (1) determine the optimal angle(s) of rotation required to accurately depict guidewire placement on imaging and (2) evaluate and describe the effects angle of rotation has on physician assessment of guidewire placement. Using a C-arm x-ray, images of cadavers with both correctly and incorrectly placed guidewires were taken at 5° increments of internal and external rotation of the cadaveric lower extremity and assessed for accuracy of guidewire depiction. The images revealed that the correctly placed guidewire appeared displaced medially at angles of 35° and 40° of external rotation. Conversely, the incorrectly placed guidewire appeared to be correctly placed at between 10° and 40° of external rotation. These images were then disseminated to various physicians including orthopedic surgeons and podiatrists to determine the ability of physicians to correctly appreciate guidewire placement. Using the responses from 35 physicians, it was found that certain angles of internal and external rotation preclude physicians from correctly determining guidewire placement. We found, based on chi-square analysis, that we were able to reject our null hypothesis with a p value of <.001 leading to the conclusion that indeed angle of rotation and guidewire placement can lead to false depictions of guidewire placement. In conclusion, our study gave objective measurements to guide foot placement during tibiotalocalcaneal fusion to decrease the risk incorrectly depicted medial guidewire placement and subsequent incorrect intramedullary nail placement.