Related Experiment Video
Updated: Aug 8, 2026
Clinical Efficacy of Tissue-Bone Homeostasis Manipulation on Soft Tissue Balance and Function in Knee Osteoarthritis
Published on: June 16, 2026
Multicenter randomized controlled trial comparing early versus late aquatic therapy after total hip or knee
Thoralf R Liebs1, Wolfgang Herzberg, Wolfgang Rüther
1Department of Orthopaedic Surgery, University of Schleswig-Holstein Medical Center, Kiel Campus, Kiel, Germany. liebs@liebs.eu
Objective:
To evaluate if the timing of aquatic therapy influences clinical outcomes after total knee arthroplasty (TKA) or total hip arthroplasty (THA).
Design:
Multicenter randomized controlled trial with 3-, 6-, 12-, and 24-month follow-up.
Setting:
Two university hospitals, 1 municipal hospital, and 1 rural hospital.
Participants:
Patients (N=465) undergoing primary THA (n=280) or TKA (n=185): 156 men, 309 women.
Intervention:
Patients were randomly assigned to receive aquatic therapy (pool exercises aimed at training of proprioception, coordination, and strengthening) after 6 versus 14 days after THA or TKA.
Main Outcome Measures:
Primary outcome was self-reported physical function as measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at 3-, 6-, 12-, and 24-months postoperatively. Results were compared with published thresholds for minimal clinically important improvements. Secondary outcomes included the Medical Outcomes Study 36-Item Short-Form Health Survey, Lequesne-Hip/Knee-Score, WOMAC-pain and stiffness scores, and patient satisfaction.
Results:
Baseline characteristics of the 2 groups were similar. Analyzing the total study population did not result in statistically significant differences at all follow-ups. However, when performing subanalysis for THA and TKA, opposite effects of early aquatic therapy were seen between TKA and THA. After TKA all WOMAC subscales were superior in the early aquatic therapy group, with effect sizes of WOMAC physical function ranging from .22 to .39. After THA, however, all outcomes were superior in the late aquatic therapy group, with WOMAC effect sizes ranging from .01 to .19. However, the differences between treatment groups of these subanalyses were not statistically significant.
Conclusions:
Early start of aquatic therapy had contrary effects after TKA when compared with THA and it influenced clinical outcomes after TKA. Although the treatment differences did not achieve statistically significance, the effect size for early aquatic therapy after TKA had the same magnitude as the effect size of nonsteroidal anti-inflammatory drugs in the treatment of osteoarthritis of the knee. However, the results of this study do not support the use of early aquatic therapy after THA. The timing of physiotherapeutic interventions has to be clearly defined when conducting studies to evaluate the effect of physiotherapeutic interventions after TKA and THA.