Two-year clinical outcomes and complication rates in anatomic and reverse shoulder arthroplasty implanted with Exactech GPS intraoperative navigation.

INTRODUCTION: We compared the 2-year clinical outcomes of both anatomic and reverse total shoulder arthroplasty (ATSA and RTSA) using intraoperative navigation compared to traditional positioning techniques. We also examined the effect of glenoid implant retroversion on clinical outcomes. HYPOTHESIS: In both ATSA and RTSA, computer navigation would be associated with equal or better outcomes with fewer complications. Final glenoid version and degree of correction would not show outcome differences. MATERIAL AND METHODS: A total of 216 ATSAs and 533 RTSAs were performed using preoperative planning and intraoperative navigation with a minimum of 2-year follow-up. Matched cohorts (2:1) for age, gender, and follow-up for cases without intraoperative navigation were compared using all standard shoulder arthroplasty clinical outcome metrics. Two subanalyses were performed on navigated cases comparing glenoids positioned greater or less than 10° of retroversion and glenoids corrected more or less than 15°. RESULTS: For ASTA, no statistical differences were found between the navigated and non-navigated cohorts for postoperative complications, glenoid implant loosening, or revision rate. No significant differences were seen in any of the ATSA outcome metrics besides higher internal and external rotation in the navigated cohort. For RTSA, the navigated cohort showed an ARR of 1.7% (95% CI 0%, 3.4%) for postoperative complications and 0.7% (95% CI 0.1%, 1.2%) for dislocations. No difference was found in the revision rate, glenoid implant loosening, acromial stress fracture rates, or scapular notching. Navigated RTSA patients demonstrated significant improvements over non-navigated patients in internal rotation, external rotation, maximum lifting weight, the Simple Shoulder Test (SST), Constant, and Shoulder Arthroplasty Smart (SAS) scores. For the navigated subcohorts, ATSA cases with a higher degree of final retroversion showed significant improvement in pain, Constant, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), SST, University of California-Los Angeles shoulder score (UCLA), and Shoulder Pain and Disability Index (SPADI) scores. No significant differences were found in the RTSA subcohort. Higher degrees of version correction showed improvement in external rotation, SST, and Constant scores for ATSA and forward elevation, internal rotation, pain, SST, Constant, ASES, UCLA, SPADI, and SAS scores for RTSA. CONCLUSION: The use of intraoperative navigation shoulder arthroplasty is safe, produces at least equally good outcomes at 2 years as standard instrumentation does without any increased risk of complications. The effect of final implant position above or below 10° of glenoid retroversion and correction more or less than 15° does not negatively impact outcomes.

High intraoperative accuracy and low complication rate of computer-assisted navigation of the glenoid in total shoulder arthroplasty.

BACKGROUND: Preoperative planning software with intraoperative guidance technology is increasingly being used to manage complex glenoid deformity in anatomic total shoulder arthroplasty (TSA) and reverse TSA. The aim of this study was to review the intraoperative efficacy and complications of computer-assisted navigation (CAN) surgery for the treatment of glenoid deformity in TSA. METHODS: We performed a retrospective review of all TSAs implanted using a single computer navigation shoulder system. All patients underwent preoperative planning with computed tomography-based preoperative planning software. The starting point on the glenoid and the final version and inclination of the central post (cage) of the glenoid component were reviewed on the intraoperative navigation guidance report and compared with these parameters on the preoperative plan for each patient. The intraoperative accuracy of CAN for glenoid positioning was determined by the deviation of the starting point and final position of the central cage drill in the glenoid compared with the preoperative plan. Data regarding intraoperative complications and the number of times the navigation system was abandoned intraoperatively were collected. RESULTS: A total of 16,723 anatomic TSAs and reverse TSAs performed worldwide with the aforementioned navigation system were included in this review. In 16,368 cases (98%), every step of the navigation procedure was completed without abandoning use of the system intraoperatively. There was minimal deviation in the intraoperative execution of the preoperative plan with respect to version (0.6° ± 1.96°), inclination (0.2° ± 2.04°), and the starting point on the glenoid face (1.90 ± 1.2 mm). In this cohort, 9 coracoid fractures (0.05%) were reported. CONCLUSION AND DISCUSSION: This study demonstrates the safety and efficacy of CAN for glenoid implantation in TSA. Future studies should focus on assessing the impact of CAN on the longevity and survival of glenoid components and improving the cost-effectiveness of this technology.