Predictive Factors of Short Inpatient Stay Following Total Knee Replacement

Enhanced Recovery after Surgery (ERAS) protocols adopt a multidisciplinary approach in perioperative care to reduce Length of Stay (LOS). This study aims to identify predictive factors resulting in short-stay following TKR with an ERAS programme.

Retrospective analysis was performed on a consecutive series of patients who underwent unilateral TKR by a single surgeon in a tertiary institution between August 2019 and December 2021. Patient demographics, comorbidities and length of stay were collected using Electronic Medical Records. Short-stay was defined as LOS within 1 day or less, while standard-stay was defined as LOS exceeding 2 days or more. Statistical analysis was performed using R version 4.3.1. Logistic regression was performed for multivariate analysis.

Ninety-nine patients were included in the study, comprising 45 short-stay patients and 54 standard-stay patients. Short-stay patients were significantly younger (mean 66.1, 95% CI [64.5, 67.7], p = 0.0212) than standard-stay patients (mean 69.2, 95% CI [67.1, 71.2]). There was a significantly lower mean BMI among short-stay patients (26.98, 95% CI [25.52, 28.45], p = 0.021) than among standard-stay patients (29.31, 95% CI [27.96, 30.66]). A significantly higher proportion of short-stay patients (84.4%, 95% CI [73.4, 95.5], p = 0.00132) were premorbid community ambulant without aids than standard-stay patients (51.9%, 95% CI [38.1, 65.6]). There was no significant difference in sex, race, smoking, American Society of Anaesthesiologists score and Charlson Comorbidity Index (p > 0.05). Multivariate logistic regression revealed the following significant factors: Age < 75 (p = 0.0293), BMI < 25 (p = 0.00688), and premorbid community ambulant without aids (p = 0.0402).

In conclusion, predictive factors for short-stay after TKR include age < 75, BMI < 25 and being premorbid community ambulant without aids.