Accuracy of Blueprint in Predicting Range of Motion One Year After Reverse Total Shoulder Arthroplasty.

Abstract

/hypothesis: Blueprint 3D CT software has a functionality that predicts impingement-free range of motion with the limits of range of motion determined at which bone and/or prosthetic impingement occurs. To the best of knowledge, there is only one previously published study that assessed the ability for the Blueprint software to predict actual postoperative range of motion after reverse total shoulder arthroplasty. The hypothesis of this study was that 1) mean Blueprint predicted impingement-free range of motion will be statistically similar to the mean actual range of motion one year after reverse total shoulder arthroplasty and 2) there will be a correlation between Blueprint predicted impingement-free range of motion and the actual range of motion one year after reverse total shoulder arthroplasty. A retrospective review of patients that had Blueprint planning prior to undergoing reverse total shoulder arthroplasty from March 2017 through May 2021 was reviewed. At one-year follow-up. flexion, external rotation at the side, abduction, abduction / external rotation, abduction / internal rotation, and internal rotation behind the back were measured. The preoperatively predicted flexion, extension, abduction, external rotation, and internal rotation were recorded from the Blueprint software. Group 1 analysis examined the predicted vs actual range of motion for all 127 patients regardless if intraoperative component modifications were made. Group 2 examined the predicted vs actual range of motion of only the patients that did not have intraoperative changes that would affect the preoperative range of motion prediction (n=97). Group 3 examined the predicted vs actual range of motion of Group 2 combined with the 30 patients that had post-hoc Blueprint planning modifications to account for the changes made intraoperatively (combined sample size = 127). One-hundred-twenty-seven patients of the 141 patients (90%) were available for one year follow-up. When examining the mean of all three groups, the actual range of motion and predicted range of motion was statistically significantly different (p<0.0001) for flexion, external rotation, abduction, abduction/ external rotation, and abduction / internal rotation. In Group 1, a very weak or poor correlation was found between predicted internal rotation and actual abducted/internal rotation (r=0.19; p=0.04). For all other range of motion metrics in Groups 1, 2, and 3, there were no correlations between predicted and actual range of motion (p >.07). In its current state, preoperative Blueprint 3D CT planning software is unable to accurately predict range of motion one year after reverse total shoulder arthroplasty.