Readmissions at 30 Days and 1 Year for Implant-Associated Complications Following Primary Total Hip and Knee Arthroplasty: A Population-Based Study of 34,392 Patients Across Austria

Background: The primary aim of this study was to assess 30-day and 1-year rates for unplanned readmission due to implant-associated complications following total hip (THA) or total knee arthroplasty (TKA) in Austria. Secondary endpoints were reasons for readmission and differences in revision risk depending on demographics and hospital size.

Methods: Data on patients receiving THA (n = 18,508) or TKA (n = 15,884) in orthopaedic and trauma units across Austria within a 1-year period (January 2021 to December 2021) were retrieved from a government-maintained database. The absolute and relative frequencies of unplanned readmissions were calculated. Risk factors for 30-day and 1-year readmission following THA or TKA due to implant-associated complications were investigated.

Results: The 30-day and 1-year readmission rates for any implant-associated complication were 1.0% (339 of 34,392) and 3.0% (1,024 of 34,392), respectively. Relative to the overall readmission rate for any complication at 30 days (n = 1,952) and 1 year (n = 12,109), readmission rates for implant-associated complications were 17.4 and 8.5%, respectively. The 30-day readmission rates were higher in THA (1.2%) than TKA patients (0.8%; P = 0.001), while it was the opposite at 1 year (THA, 2.7%; TKA, 3.3%; P < 0.001). Mechanical complications (554 of 1,024) were the most common reason for 1-year readmission. Prolonged length of in-hospital stay independently associated with increased 1-year readmission risk in THA and TKA patients. Treatment at large-sized hospitals was associated with a higher 1-year readmission risk in TKA patients.

Conclusions: The 30-day and 1-year readmission rates for implant-associated complications following THA or TKA in Austria are lower than reported in other countries, with similar risk factors and reasons for readmission. Considering that almost 20% of unplanned hospital readmissions following total joint arthroplasty are attributable to implant-associated complications, optimization of in-hospital and postdischarge medical care for these patients is warranted.