Fall-related admissions after fast-track total hip and knee arthroplasty – cause of concern or consequence of success?

BACKGROUND: Total hip (THA) and knee arthroplasty (TKA) are common procedures in elderly persons, who are at potential increased risk of postoperative fall due to loss of muscle strength and impaired balance. Fast-track surgery with early mobilization and opioid-sparing analgesia have improved outcomes after these procedures, but early mobilization and short hospitalization length of stay (LOS) could potentially increase the risk of falls after discharge. We investigated injuries, circumstances, and the timing of fall-related hospital admissions 90 days after fasttrack THA and TKA. METHODS: This was a prospective, descriptive multicenter study on fall-related hospital admissions, in 5145 elective fast-track THA and TKA patients, with complete 90-day follow up through the Danish National Patient registry and medical charts. RESULTS: Of 83 (1.6%) fall-related hospital admissions, 43 (51.8%) were treated in the Emergency Room and 40 (48.2%) were admitted to a regular ward. The median LOS after surgery was 3 days (interquartile range [IQR]: 2–3) in fallers versus (vs) 2 days (IQR: 2–3) (P=0.022) in patients without falls. Injuries were classified as “none” or minor in 39.8%, moderate in 9.6%, and major in 50.6%. Most falls (54.8%) occurred within 1 month of discharge. Falls due to physical activity (12.0%) and extrinsic factors (14.5%) occurred later than did surgery-related falls (73.5%), contributing to 40% of all falls >30 days after discharge. In multivariate analysis, age (odds ratio [OR]: 1.05; 95% confidence interval [CI]: 1.0–1.08) (P=0.001), living alone (OR: 2.09; 95% CI: 1.20–3.62) (P=0.009), and psychiatric disease (OR: 2.80; 95% CI: 1.42–5.50) (P=0.001) were associated with surgery-related falls, whereas the use of a walking aid (OR: 1.20; 95% CI: 0.67–2.16) (P=0.544) and LOS ≤4 days (OR:1.19; 95% CI: 0.52–1.28) (P=0.680) was not. CONCLUSION: Hospital admissions due to falls are most frequent within the first month after fast-track THA and TKA. The overall incidence of surgery-related falls amongst these patients is low, declines after the first month, and is related to patient characteristics rather than short LOS. The effect of interventions aimed at surgery-related falls should focus on the first 30 days after surgery and differentiate between the causes of falling.