Archives of Physical Medicine and Rehabilitation · Apr 17, 2026

Feasibility and Preliminary Effects of Inspiratory Muscle Training in Patients With Knee Osteoarthritis Awaiting Total Knee Arthroplasty: An 8-Week, Pilot Randomized Controlled Trial

By Su S, Yu CC, Yao Z et al.

OBJECTIVE: To evaluate the feasibility and preliminary effects of inspiratory muscle training (IMT) on aerobic capacity in patients with knee osteoarthritis (OA) awaiting total knee arthroplasty (TKA). DESIGN: Pilot randomized controlled trial. SETTING: Laboratory, physical therapy center, and the physician's room. PARTICIPANTS: Forty participants with knee OA scheduled for TKA were randomized 1:1. Five withdrew before commencing the intervention, resulting in 35 participants (mean age ± SD, 66.8±7.2 years; 26 women) for the modified intention-to-treat analysis. The per-protocol analysis included 24 participants with ≥60% adherence. INTERVENTIONS: Both groups completed 8 weeks of home-based preoperative rehabilitation; the IMT group received additional IMT. MAIN OUTCOME MEASURES: The primary outcome was feasibility (recruitment, retention, adherence, safety). Secondary outcomes included aerobic capacity (maximum oxygen consumption [V̇o₂max]), estimated from the 6-minute walk test using a regression equation validated in older adults (SE=3.99 mL/kg/min). Additional outcomes included inspiratory muscle strength, pain intensity (numeric rating scale), knee function (Western Ontario and McMaster Osteoarthritis Index), and health-related quality of life (12-item Short Form Health Survey). RESULTS: The recruitment rate was 56%, and 31 participants completed baseline and postintervention assessments (retention 89%). Adherence rates were high (median IMT=100%; median control=92.5%), and no major adverse events occurred. In adherent participants (≥60%, n=24), IMT led to greater improvements in V̇o₂max than in controls (mean difference=2.38 mL/kg/min, 95% confidence interval, 0.77-3.98, P=.005). Inspiratory muscle strength increased significantly in the IMT group (absolute change=21.83 cmH₂O, relative change=0.31 cmH₂O/kg, all P<.001). Pain, knee function, and quality of life improved (all P<.05). CONCLUSIONS: An 8-week IMT program delivered alongside standard preoperative rehabilitation is feasible and safe and has the potential to improve estimated V̇o₂max and related outcomes in patients awaiting TKA. These pilot findings support the need for larger confirmatory trials.

doi.org/10.1016/j.apmr.2026.04.011PubMed 42002253Interventions