The influence of computed tomography preoperative planning on clinical outcomes after anatomic total shoulder arthroplasty: a matched cohort analysis

Evaluation, characterization, and correction of glenoid deformity are an important part of performing anatomic total shoulder arthroplasty (TSA). Three-dimensional computed tomography (3D CT) planning has been shown to improve implant position, but the impact on clinical outcomes is less clear. The purpose of the current study is to compare clinical outcomes of TSA performed with 3D CT preoperative planning with matched controls performed without CT-based planning. Utilizing a multicenter shoulder arthroplasty registry, patients who underwent a TSA with 2-year clinical follow-up were retrospectively identified. These patients were divided into two cohorts based on technique for glenoid guide pin placement based on surgeon preference: 1) those who utilized 3D preoperative templating with or without patient-specific instrumentation (PSI) and 2) a control group of TSAs performed without 3D CT preoperative planning. The two groups were matched 1:1 based on age, sex, and baseline American Shoulder and Elbow Surgeons (ASES) score. Patient-reported outcomes and active range of motion (ROM) obtained at 2 years postoperatively were assessed and compared between the two cohorts. A subgroup analysis was also performed comparing outcomes in patients with 3D CT preoperative planning with and without PSI. Data collection was performed on 84 study patients with 3D CT preoperative planning (51 with PSI and 33 without) and 84 matched control patients without CT-based planning (168 patients in total). Baseline characteristics were similar between the groups. Improvement from baseline for the ASES score (study group: 45.4, controls: 39.0, P = .029) and external rotation at 90° of abduction (study group: 42° vs. 29°, P = .009) was significantly greater in the CT-based planning group than that in matched controls. There were no other significant differences in improvement in outcomes or ROM between the two groups. Within the 3D CT cohort, there were no significant differences in patient-reported outcomes or ROM between TSAs performed with or without PSI. A significantly greater percentage of patients with 3D CT planning achieved a patient acceptable symptomatic state than controls (89% vs. 75%, P = .016). TSAs performed with 3D CT preoperative glenoid planning with or without utilization of PSI were associated with statistically significantly greater improvement from baseline in ASES scores and external rotation at 90° of abduction than TSA performed without 3D CT planning. The clinical significance of this finding is unclear, as the differences failed to meet a clinically significant threshold.