Data source and study design

Patient records were queried from the PearlDiver Mariner Database (PearlDiver Inc), a commercially available administrative claims database that contains deidentified patient data from the inpatient and outpatient settings. The database contains the medical records of patients across the United States from 2010 through the first quarter of 2021, which were collected by an independent data abstractor. This study used the “M151Ortho” data set within PearlDiver, which contains a random sample of 151 million patients. All types of health insurance payors are represented, including commercial, private, and government plans. Researchers extracted data using the current procedural technology (CPT) and International Classification of Diseases, Ninth and Tenth Revision (ICD-9/ICD-10) diagnosis and procedural codes. Institutional Review Board exemption was granted as provided data were deidentified and compliant with the Health Insurance Portability and Accountability Act. No outside funding was received for this study.

A retrospective cohort study was conducted to investigate the rate of ipsilateral CTS diagnosis following several arthroscopic shoulder procedures. Using CPT codes, patients who underwent arthroscopic RCR (CPT-29827), biceps tenodesis (CPT-29828), and/or labral repair (CPT-29806 or CPT-29807) were identified and filtered for the first instance of each CPT code. For the RCR cohort, patients were still included if they had additional same-day procedures, whereas for the biceps tenodesis cohort, patients with same-day RCR and/or labral repair were excluded. For the labral repair cohort, patients with same-day RCR and/or biceps tenodesis were excluded. These exclusions were chosen to evaluate isolated biceps tenodesis and labral repair while allowing for analysis of the impact of additional procedures on CTS risk following RCR repair. In order to ensure laterality, patients were required to have an ICD-10 diagnosis code for a right- or left-sided rotator cuff tear, biceps tendon injury, or labral tear on the same day of the respective CPT codes to be included. The requirement for each patient to have an ICD-10 diagnosis code limited the beginning of study period to October 1, 2015. Patients that had a code for unspecified side or bilateral diagnoses were excluded. Additionally, patients who had a code for a contralateral rotator cuff tear, biceps tendon injury, or labral tear within 1 year were excluded to ensure that complications could be tied to the operative arm. Patients with a previous diagnosis of CTS were excluded. Codes to define each cohort are provided in Appendix A.

To limit potential transfer bias, only patients with continuous database enrollment for at least 2 years after the index procedure were included. Patients were additionally required to have an active enrollment for 3 months prior to the procedure to ensure capture of comorbidities for analysis. Subsequently, patients who had a CTS diagnosis on the ipsilateral side as their operative shoulder or on the contralateral side within 1 year of their index procedure were identified. Among those with a diagnosis, patients who underwent an injection (CPT-20526) or operative carpal tunnel release (CPT-29848 or CPT-64721) within 1 year of their CTS diagnosis were identified. Rates of comorbidities among the cohort that developed ipsilateral CTS were compared with those who did not have a CTS diagnosis after surgery. The mean Elixhauser comorbidity index (ECI) was also calculated by PearlDiver software and compared between the two groups.¹² Codes to define comorbidities and complications are provided in Appendix B.