An Analyses of the Oxford Shoulder Score and its Relationship to Early Joint Revision in the New Zealand Joint Registry.

BACKGROUND Primary shoulder arthroplasties significantly improve shoulder function and have acceptable prosthesis survival for various indications. Currently, no validated shoulder questionnaire exists that can anticipate the early failure of primary shoulder arthroplasties. This study hypothesized the Oxford shoulder score (OSS) after primary shoulder arthroplasty at six months would be significantly associated with early revision procedures. METHODS Data on all primary and revision shoulder arthroplasties covering the period of January 1, 1999, to December 31, 2019, was obtained from the New Zealand Joint Registry. The OSS questionnaires at six months were analyzed with regards to their relationship to revision within two years from the questionnaire date. Confounding risk factors were adjusted for in multivariate logistic regression analysis RESULTS: Statistical analysis revealed the six-month OSS had a significant association with revision in the following two years for TSA, RSA and HA (p < 0.001). An Oxford shoulder score of ≤ 44 for TSAs, ≤ 40 for RSAs, and ≤ 33 for HAs accounted for 68.9%, 63.1% and 50.7% respectively while capturing at least 85% of revisions for all prostheses within the following two years. CONCLUSION This study confirms that a poor Oxford shoulder score at six months is an independent risk factor for early revision after TSA, RSA and HA. We recommend discharging patients with a six-month OSS greater than the identified threshold values for each prosthesis to improve resource efficiency. LEVEL OF EVIDENCE Basic Science Study; Validation of Outcome Instrument.