Is Immediate Postoperative Radiograph Necessary Following Robotic-Assisted Total Knee Arthroplasty?

Background The necessity of immediate postoperative radiographs following total knee arthroplasty (TKA) has long been debated. With the increasing use of robotic-assisted TKA (RTKA), and thus more precise implant placement, the need for immediate postoperative radiographs to determine implant positioning may be unnecessary. We sought to evaluate implant position on the immediate postoperative radiographs following RTKA to determine their necessity. Methods A retrospective review of 150 RTKAs was performed. The posterior slope for all TKAs were recorded based on the preoperative three-dimensional template. Additionally, two independent trained researchers (JG/LB) each measured the posterior slope of the postoperative day 0 (POD0) radiograph and postoperative 2 week radiograph. The difference in posterior slope measurement between template and POD0, between template and 2 weeks, and between POD0 and 2 weeks was calculated. Results Of the 150 TKAs performed, there were no periprosthetic fractures found on the POD0 radiograph. The mean difference between the templated posterior slope and measured posterior slope on POD0 was 0.04 degrees (SD 1.01)(p = 0.615). There was a weak correlation between the two values (rs [95% CI] 0.38 [0.21, 0.53]). When comparing the template to the 2-week radiographs, there was a mean difference of 0.02 degrees (SD 0.48)(p = 0.556).  However, there was a moderate to strong correlation noted (rs [95% CI] 0.71 [0.61, 0.79]). Comparison of the mean posterior slope from POD0 radiograph to that of 2 week radiograph showed a mean difference of 0.06 degrees (SD 1.0)(p = 0.427). A weak correlation was found between these two values (rs [95% CI] 0.43 [0.26, 0.56]). Conclusions Given the accuracy and precision of RTKA, along with the ability to decrease cost and radiation, immediate postoperative radiograph may be unnecessary, when pertaining to the uncomplicated RTKA. However, if there is concern for intraoperative fracture, long stems placed in a revision arthroplasty or other intraoperative complications then postoperative radiographs are encouraged. .