Summary

Patients who underwent two component revision surgery had lower rates of recurrent instability requiring a second revision surgery, overall complications, and fracture than patients who underwent one component revision.

Abstract

Purpose

Instability after total shoulder arthroplasty (TSA) is a post-operative complication that has profound effects on patient function and morbidity. However, clinical management of prosthetic instability remains controversial. Surgeons may opt to revise either the humeral or glenoid component (one-component revision) or both the humeral and glenoid component simultaneously (two-component revision). It is unknown whether the revision surgical approach chosen affects surgical outcomes and complication rates. We hypothesized that use of a two-component revision approach to manage prosthetic shoulder instability would be associated with a lower recurrent instability rate.

Methods

The PearlDiver database was queried for patients who had primary total shoulder arthroplasties (TSA) using CPT-23472 and filtering for the first instance. This CPT code includes both anatomic and reverse shoulder arthroplasty. Patients with inactive PearlDiver records 5 years after the primary TSA were excluded. PearlDiver was then queried for patients who had instability following the primary TSA using instability related ICD-9-D and ICD-10-D codes. Outcomes were compared between two first revision cohorts that defined how the instability was managed: CPT-23473 (one component revision) and CPT-23474 (two component revision). Primary outcome was any second revision surgery performed for recurrent instability following the first revision surgery. Secondary outcomes were post-operative infection, fracture, mechanical complication, and other complications. Outcomes were compared using chi-squared tests.

Results

1380 patients were included in the study and of these patients, 521 underwent a one component first revision and 859 underwent a two-component first revision. Patients who underwent one component revision showed a significantly greater second revision rate than those who underwent two component revision (21.1% vs 14.4%, p<0.002). Overall, patients who underwent one component revision experienced greater rates of post-operative complications than the two-component revision group (51.8% vs 44.9%, p<0.02). When types of complications were analyzed, there was a greater rate of fracture in the one component group (8.8% vs 5%, p<0.007 ). There was no significant difference between groups in terms of infection (22.1% vs 17.8%), mechanical complications (17.9% vs 17%), and other complications (29.9% vs 27%).

Conclusions

High recurrent instability and complication rates after revision for prosthetic shoulder instability demonstrate that management of these cases remains challenging. Patients who underwent two component revision surgery had lower rates of recurrent instability requiring a second revision surgery, overall complications, and fracture than patients who underwent one component revision. Our findings support the hypothesis that choice of revision surgical approach for managing instability following primary shoulder arthroplasty has a meaningful impact on patients’ surgical outcomes.