Summary

While conversion from RCR to RTSA remains a rare occurrence, patient characteristics such as increasing age, obesity, and osteoporosis are identified as predicting the salvage operation.

Abstract

Background

While the management of rotator cuff repair (RCR) failure remains challenging, reverse total shoulder arthroplasty (RTSA) has increasingly been utilized as a salvage with good clinical outcomes. In the context of RCR failure, metabolic comorbidities such as diabetes mellitus (DM), obesity, and hyperlipidemia have been shown to degrade outcomes. Surgery-specific patient characteristics such as osteoporosis, vitamin-D deficiency, and smoking status have also been identified in literature to promote higher rates of failure after RCR. These characteristics, however, have not been investigated in the context of predicting RTSA after RCR. Herein, we describe the rate of conversion from RCR to RTSA, as well as those patient characteristics that can be used to predict this outcome.

Methods

A national insurance database was searched from 2007 to 2016 for all patients who underwent RCR and RTSA subsequently. Current Procedural Terminology (CPT) codes and International Classification of Diseases Ninth Revision (ICD-9) procedural codes were used to identify RCRs and RTSAs. Laterality modifiers for the primary surgery were used to identify subsequent conversions to RTSAs. Patients with ICD-9 diagnostic codes for proximal humerus fractures were excluded. Patient characteristics including age, gender, Charlson Comorbidity Index (CCI), smoking status, diabetes mellitus (DM), obesity, hyperlipidemia (HLD), vitamin-D deficiency and osteoporosis were included in the analysis. Patient age was described from 0-59, 60-69, 70-74, and 75+ years old. Dichotomous data were analyzed with chi-squared testing. Multivariable logistic regression was used to predict conversion from RCR to RTSA.

Results

Included in the study were 41,467 patients (41,844 shoulders) who underwent arthroscopic RCR. Of all arthroscopic RCRs, 163 patients underwent a subsequent RTSA. The average time from RCR to RTSA was 541.6 days (median 364.0 days). The conversion rates for the 60 – 69, 70 – 74, and 75+ years-old cohorts were significantly higher than the 0 – 59 year-old cohort (0.34%, 0.66%, 0.64% vs 0.16%, respectively). Increasing age also predicted conversion to RTSA in multivariable regression. Of all comorbidities, overall increased comorbidity burden (CCI > 3) most significantly predicted conversion from RCR to RTSA (OR 2.05). Of all patient characteristics with basic science evidence for worse RCR outcomes, obesity and osteoporosis most strongly predicted conversion from RCR to RTSA.

Conclusions

Conversions of RCRs to RTSAs was a rare occurrence (0.39%). Conversion surgery was performed on average 1.5 years after the RCR. All older age groups had at least two-fold higher conversion rates when compared to the 0 – 59 year-old patient cohort. Of all patient characteristics, increasing age, obesity, and osteoporosis most significantly predicted conversion from RCR to RTSA. Overall, a higher comorbidity burden also predicted conversion surgery. A history of smoking, diabetes, hyperlipidemia, and Vitamin-D deficiency were not found to predict conversion surgery, despite evidence in orthopaedic literature supporting worse RCR outcomes.