The primary aim of this study was to identify risk factors and validate earlier reported risk factors for Prosthetic Joint Infection (PJI) after hemiarthroplasty. The secondary aim was to assess peri‑operative clinical outcomes, adverse events and mortality rates in PJI patients after hemiarthroplasty.

A prospective hip fracture database was used to obtain data for this observational cohort study. Patients who underwent hemiarthroplasty between 2011 and 2021 were included. A PJI was diagnosed by the Musculoskeletal Infection Society criteria. Univariable and multivariable analyses were performed to identify factors highly associated with a PJI.

In total, 2044 patients were analysed of which 72 patients (3.5 %) developed PJI. The multivariable analysis showed that Body Mass Index (BMI) >30 (OR2.84, P = 0.020), operating time of <45 min (OR=2.80, P = 0.002), occurrence of haematoma (OR=6.24, P<0.001), decreasing level of hemoglobin (OR=1.62, P = 0.001) and re-operation for luxation (OR=9.25, P<0.001) were significant independent prognostic risk factors for development of PJI after hemiarthroplasty. Diabetes Mellitus (OR=0.34, P = 0.018) and >20 hemiarthroplasties performed by the surgeon in the previous year (OR=0.33, P = 0.019) were prognostic protective factors. In patients with PJI, 40 % (n = 29) died within one year after surgery, compared with 27 % (n = 538) in patients without PJI (OR=1.80, P = 0.017).

Independent significant prognostic factors highly associated with PJI after hemiarthroplasty were BMI >30, operating time of <45, decreasing level of hemoglobin, occurrence of haematoma and re-operation for luxation. Diabetes Mellitus and >20 hemiarthroplasties performed by the surgeon in the previous year were prognostic protective factors for the development of PJI. PJI was associated with significantly higher 1-year all-cause mortality.