Summary

Patients who received a CT scan prior to undergoing TSA had an increased revision rate and complication rate compared to those who did not.

Abstract

Purpose

Pre-operative 3D computer tomography (CT) planning increases the accuracy of component placement during total shoulder arthroplasty (TSA), but it is unclear whether planning translates to improved clinical outcomes. As a result, the benefit of a pre-operative CT may be challenged within a value-based care setting. We hypothesized that patients who had a CT scan prior to TSA would have a lower revision rate compared to those who did not.

Methods

A large insurance claims database was queried for patients who had a TSA from 2015 through the first quarter of 2022 using CPT code 23472. Patients that had any upper extremity fracture were excluded. Primary outcome was revision rate and secondary outcome was post-operative complication. Outcomes were compared across the overall cohort, as well as across four diagnostic subgroups: (primary osteoarthritis of the shoulder, rotator cuff tear, rotator cuff arthropathy, and shoulder pain). Cohort matching for gender, age, and Charles comorbidity index (CCI) was used to control for confounding variables. Outcomes were compared using chi-squared tests.

Results

112,571 patients met inclusion criteria and were included in the study, of which 23,212 received a pre-operative CT. Overall, patients who received a CT scan had a higher revision rate (4.8% vs 2.9%, p < 0.001) and complication rate (8.4% vs 6.2%, p < 0.001), than those who did not. Across diagnostic subgroups, all groups demonstrated significantly increased revision rates in patients who received pre-operative CT scans (Osteoarthritis: 4.6% vs 2.8%; Rotator Cuff Tear: 5.5% vs 3.2%; p < 0.001; Rotator Cuff Arthropathy: 5.1% vs 3.2%; Pain: 5.0% vs 3.2%, p<0.001 for all). All diagnostic subgroups also showed increased complication rates in patients who received a pre-operative CT scan (Osteoarthritis: 8.3% vs 6.4%; Rotator Cuff Tear: 9.1% vs 7.0%; Rotator Cuff Arthropathy: 10.0% vs 7.7%; Pain: 8.8% vs 6.7%, p<0.001 for all). Patients with a diagnosis of osteoarthritis, rotator cuff arthropathy, or pain had a significant greater chance of receiving a pre-op CT (OR 2.3, 1.2, 2.2, p < 0.001). Patients with a diagnosis of rotator cuff tear were less likely to receive a pre-op CT (OR 0.9, p<0.001).

Conclusions

Patients who received a CT scan prior to undergoing TSA had an increased revision rate and complication rate compared to those who did not. Patients who were presumably less likely to have glenoid deformity (a diagnosis of rotator cuff tear), were less likely to receive a CT scan. Consequently, we believe the inferior outcomes in patient who received pre-operative CTs are likely due to inherent anatomic differences. Further research is needed to define the value of pre-operative CTs by controlling for outcomes based on glenoid deformity.