Impact of cervical spine pathology on outcomes after total shoulder arthroplasty

Cervical spine pathology can affect the supporting muscles and function of the shoulder and contribute to shoulder and arm pain and hence may impact postoperative outcomes following shoulder arthroplasty. The purpose of this study was to evaluate the impact of a history of cervical spine arthrodesis and its timing, before or after total shoulder arthroplasty (TSA), on the outcomes of TSA. Our hypothesis is that a history of cervical arthrodesis (CA) will negatively impact patient outcomes after shoulder arthroplasty.

A retrospective analysis was performed on a prospectively collected cohort at a single institution. Anatomic (aTSA) and reverse TSA (rTSA) patients with CA were identified and compared to a cohort of patients without CA (NCA) enrolled in an institutional registry from 2011 to 2020. Demographic characteristics, diagnoses, implant type, range of motion, adverse events, and clinical outcome metric scores (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], Constant, Shoulder Function score, patient satisfaction) were recorded. Outcomes between cohorts were analyzed using conventional statistics as well as stratification by minimal clinically important difference and substantial clinical benefit (SCB) thresholds where applicable.

Of the 573 TSAs evaluated, 48 (20a CA-aTSA and 28 CA-rTSA) had a history of CA and 525 (280 NCA-aTSA and 245 NCA-rTSA) had no history of CA. The CA-TSA (aTSA and rTSA) had lower Constant, ASES, and Shoulder Function scores postoperatively as well as less improvement in active external rotation and an overall lower satisfaction rating (P < .05 for all) compared with NCA-TSA. The adverse event rate in the CA-TSA cohort was higher compared with the NCA-TSA cohort (25% vs. 6.5% [rTSA; P = .004] and 24.5% vs. 11% [aTSA; P = .068]). Optimal cutoff analysis showed that a time from CA to TSA of greater than 1.33 years had a sensitivity of 75.0% and specificity of 75.0% in predicting achievement of SCB for ASES score.

The current study demonstrates that patients with a history of CA undergoing shoulder arthroplasty results in lower postoperative functional outcomes, lower satisfaction, and higher rates of postoperative adverse events requiring surgical revision when compared to a cohort without a history of CA. Additionally, the current study demonstrates that a time interval of at least 16 months between CA and shoulder arthroplasty optimizes the chances of achieving SCB for ASES score.