Unfortunately, an erratum to Acta Orthop 2014; 85 (5): 488-492, doi: 10.3109/17453674.2014.934186, is required as some descriptive values in Table 1 are incorrect. The error happened as means and standard deviations were erroneously calculated from spread sheet-cells with letter formatting for some cells instead of number formatting for all cells. Hence, these cells and their values were not included in the calculation of the means and standard deviations presented in Table 1, and the TKA sample was miscalculated to 75 instead of 78 patients. The corrected Table 1 is inserted . Based on the above, the first sentence in the abstract in the “Methods” paragraph should read: “Before surgery, hip pain (THA) or knee pain (TKA), lower-extremity muscle power, functional performance, and physical activity were assessed in a sample of 153 patients and used as independent variables to predict the outcome (dependent variable) – readiness for hospital discharge – for each type of surgery. Discharge readiness was assessed twice daily by blinded assessors”. In the paper, the last sentence of the paragraph entitled “Patients and study design” should read: “The case report form was not filled out in 1 patient, which is why the final sample comprised 153 patients (75 THA and 78 TKA) (Table 1)”.
The prediction analyses, however, are correct and performed for all collected data. These analyses were performed in a later step with correct formatting of all cells, using different software that automatically detected the correct cell formats. Hence, the error outlined above was not transferred to the analyses, but the remainder of the paper remains correct.
Table 1. Patient characteristics before surgery. Values are mean (SD)