Balance and Mobility in Comparison to Patient-Reported Outcomes—A Longitudinal Evaluation After Total Hip and Knee Arthroplasty

<b>Background:</b> Balance and gait are critical for functional recovery and fall prevention following total hip (THA) and knee arthroplasty (TKA). Despite improvements in pain and joint function, residual impairments often persist. The Timed Up and Go (TUG) test and Tinetti Performance-Oriented Mobility Assessment (POMA) objectively measure postoperative mobility and balance, while patient-reported outcome measures (PROMs) assess perceived function and well-being. This study longitudinally evaluates functional measurement and PROMs to explore their interrelationships and compare recovery trajectories in THA and TKA cohorts. <b>Methods:</b> In this prospective study, 22 THA and 21 TKA patients were assessed preoperatively and at 4-6 days, 6 weeks, 3 months, and 12 months postoperatively using TUG, Tinetti, Hip Disability and Osteoarthritis Outcome Score (HOOS), Knee Injury and Osteoarthritis Outcome Score (KOOS), and clinical scores (Harris Hip Score (HHS) for THA, Knee Society Score (KSS) for TKA). Pearson correlation assessed relationships between measures. <b>Results:</b> Both cohorts demonstrated significant immediate postoperative declines in balance and mobility, recovering to baseline by 6 weeks and surpassing it by 3 and 12 months (<i>p</i> < 0.001). PROMs showed earlier and sustained improvements. Objective balance and mobility measures showed minimal correlation with PROMs but were highly interrelated from 6 weeks onward. <b>Conclusions:</b> THA and TKA patients experience early postoperative balance impairments, suggesting heightened fall risk, with functional recovery lagging behind perceived well-being, highlighting the need for cautious rehabilitation strategies.