Predictors of prolonged length of stay in shoulder arthroplasty: A study using the National Joint Registry and Hospital Episode Statistics for England.

INTRODUCTION: The volume of shoulder arthroplasties in the United Kingdom continues to rise, with 8221 cases recorded in the National Joint Registry (NJR) in 2023. Amid increasing demand and pressure on NHS resources, reducing hospital length of stay (LOS) is a key priority for improving efficiency. This study aimed to identify independent predictors of prolonged LOS following shoulder arthroplasty. METHODS: NJR data from April 2012 to March 2022 were linked with Hospital Episode Statistics (HES) for England. Prolonged LOS was defined as >2 nights (above the cohort median). Variables analysed included age, sex, Charlson comorbidity index (CCI), comorbidities, surgical indication, implant type, operating surgeon volume, and day of surgery. Univariable and multivariable logistic regression models were used to identify predictors. RESULTS: Among 47,145 patients, older age, higher CCI, and ASA grades 3 and 4 were significantly associated with extended LOS. Male patients had a 45% reduced risk of prolonged stay. Trauma-related procedures and surgeries conducted Friday-Sunday were associated with increased LOS. Patients treated by high-volume surgeons had a 19% lower risk of prolonged LOS. Several comorbidities were independently predictive; however, differed across implants. CONCLUSION: Both patient-level and system-level factors contribute to prolonged LOS. Optimising perioperative care and scheduling may reduce LOS and improve NHS resource utilisation.