Navigation in reverse total shoulder arthroplasty: a retrospective study

Background The purpose of this study was to evaluate radiographic accuracy and assess the learning curve associated with a single surgeon's transition from non-navigated to navigated reverse total shoulder arthroplasty (rTSA). Methods This was a retrospective clinical study that included 166 consecutive rTSA cases performed by a single surgeon with 84 non-navigated cases immediately followed by 82 navigated rTSA using computer-assisted navigation. Radiographic measurements included pre- and post-operative β-angle (inclination), inferior glenosphere offset, and the distance from center of rotation of the glenosphere to the tip of the coracoid (COR–C). For all radiographic measurements, intra-rater reliability was compared using intra-class correlation coefficients (ICCs). Statistical comparisons were performed using t-tests, Mann-Whitney U, and Fisher–Freeman–Halton tests. Results All radiographic measurements had excellent reliability with ICCs of >0.799. Inferior offset was significantly greater in the navigated group (7.0 ± 2.5 mm) than in the non-navigated group (5.4 ± 3.1 mm, p = 0.001). No differences were found in postoperative inclination or COR–C distance. Operative time was significantly higher with navigation (141 ± 23.5 min vs. 136 ± 30.8 min, p = 0.031). Early dislocations occurred in 4.7% of non-navigated cases and in 0% of navigated cases ( p = 0.045). Conclusion This retrospective single-surgeon study illustrates that transition to computer assisted navigation in rTSA may modestly increase operative time while improving implant positioning including inferior glenoid offset. No early postoperative dislocations were observed in the navigated group, though definitive conclusions are limited by short follow-up and limited sample size. This study demonstrates an association between the role of computer assisted navigation in improving implant accuracy, but further studies are needed to determine its clinical relevance.