Effect of baseline values on inpatient rehabilitation outcomes after total knee arthroplasty: a retrospective observational study.

Objective: To compare inpatient rehabilitation outcomes after total knee arthroplasty (TKA) between groups with different baseline scores.

Design: A retrospective observational study.

Subjects: Patients with knee osteoarthritis who have previously undergone unilateral TKA.

Methods: Patients participated in 3-week inpatient rehabilitation following TKA and were assessed for patient-reported outcome measures (PROMs), which included the Numeric Pain Rating Scale (NPRS), the Health Assessment Questionnaire (HAQ), the European Quality of Life 5 Dimensions 5 Level Version (EQ-5D-5L), and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Furthermore, mobility scores for the range of motion (ROM) and the Timed Up and Go (TUG) test were recorded at the beginning and the end of rehabilitation. Patients were divided into quartile groups based on their initial examination scores.

Results: 329 patients were enrolled in the study. The study population consisted mostly of female patients (63.8% vs 36.2%) with a mean age of 68.25 (SD 9.24) years. The personalized 21-day in rehabilitation programme was safe for all patients and had no dropouts. Patients with better PROMs scores at T1 did not have the same potential for improvement in PROMs but showed effective improvement in mobility (η² = 0.103 for changes in the WOMAC vs η²=0.502 for changes in the TUG test).

Conclusion: Regardless of the baseline scores, all patients presented significant improvements in both subjective and objective measures. Age and baseline PROMs or mobility scores did not have a significant effect on score development.