Accuracy of 3-Dimensional Planning, Implant Templating, and Patient-Specific Instrumentation in Anatomic Total Shoulder Arthroplasty

Abstract

Background: Use of 3-dimensional (3D) computed tomography (CT) preoperative planning and patient-specific instrumentation has been demonstrated to improve the accuracy of glenoid implant placement in total shoulder arthroplasty (TSA). The purpose of this study was to compare the accuracy of glenoid implant placement in primary TSA among different types of instrumentation used with the 3D CT preoperative planning. Methods: One hundred and seventy-three patients with end-stage glenohumeral arthritis were enrolled in 3 prospective studies evaluating patient-specific instrumentation and 3D preoperative planning. All patients underwent preoperative 3D CT planning to determine optimal glenoid component and guide pin position based on surgeon preference. Patients were placed into 1 of 5 instrument groups used for intraoperative guide pin placement: (1) standard instrumentation, (2) standard instrumentation combined with use of a 3D glenoid bone model containing the guide pin, (3) use of the 3D glenoid bone model combined with single-use patient-specific instrumentation, (4) use of the 3D glenoid bone model combined with reusable patient-specific instrumentation, and (5) use of reusable patient-specific instrumentation with an adjustable, reusable base. Postoperatively, all patients underwent 3D CT to compare actual versus planned glenoid component position. Deviation from the plan (in terms of orientation and location) was compared across groups on the basis of absolute differences and outlier analysis. Univariable and multivariable comparisons were performed. As the initial analyses showed no significant differences in preoperative factors or in deviation from the plan between Groups 1 and 2 or between Groups 4 and 5 across studies, the final analysis was across 3 major treatment groups: standard instrumentation (Groups 1 and 2), single-use patient-specific instrumentation (Group 3), and reusable patient-specific instrumentation (Groups 4 and 5). Results: In nearly all comparisons, there were no significant differences in the deviation from the plan (absolute differences or outlier frequency) for glenoid implant orientation or location across the 3 major treatment groups. Conclusions: This study did not demonstrate that any type of patient-specific instrumentation resulted in consistent differences in accuracy of glenoid implant placement in primary TSA with 3D CT preoperative planning. Surgeons have multiple patient-specific instrumentation options available for improving accuracy of glenoid implant placement when compared with 2D imaging without patient-specific instrumentation. Level of Evidence Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Trends and impact of three-dimensional preoperative imaging for anatomic total shoulder arthroplasty

“…Although the literature has detailed that preoperative 3D imaging may improve accuracy of component placement, no study has correlated if the use of this imaging decreases complications or revision rates. 20 In the current study, we found that patients who underwent preoperative CT scans experienced a significant reduction in the rate of revision surgery at two years postoperatively compared to matched controls without such imaging. Given that the collection period for data in this study ended in 2014 when very minimal patient-specific instrumentation technologies were widely available, we believe that the decreased revision rate is likely due to a better understanding of glenoid anatomy and the ability to better restore glenoid version.…”

How to Optimize Reverse Shoulder Arthroplasty for Irreparable Cuff Tears

“…The authors believe that preoperative planning of RSA implantation using software packages provides tremendous value to understand how to best minimize perimeter impingement and optimize component position, including correction of bone deformity and ideal component sizing and fixation (Fig. 1) [20]. The main piece of information lacking in currently available planning software packages relates to prediction and optimization of soft tissue tension.…”

Low-dose CT with metal artifact reduction in arthroplasty imaging: a cadaveric and clinical study

“…Implant position was automatically calculated with respect to the scapular coordinate system by detecting the radiopaque tantalum markers that were implanted at the time of surgery. Details of the implant position analysis have been published previously [15][16][17][18]. Fourteen parameters of glenoid position were measured using the simulated half-dose and full-dose images.…”