The Role of Hydrotherapy in Enhancing Recovery After Knee Arthroplasty: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND

Total knee arthroplasty (TKA) is a common procedure to relieve pain and restore function in osteoarthritis patients. Postoperative rehabilitation is essential to address pain, swelling, reduced range of motion, and functional limitations. Hydrotherapy, using water buoyancy and resistance, may enhance recovery, but evidence on its effectiveness after these surgeries remains limited.

METHODS

A systematic literature search was conducted across six databases: PubMed, ProQuest, Science Direct, Google Scholar, Scopus, the Cochrane Library, and PEDro, covering studies published up to 30 November 2025. Only prospective randomized controlled trials were considered for inclusion. Studies such as case reports, uncontrolled case series, and those focused on outcomes other than postoperative pain and decreased muscle strength in patients undergoing total knee arthroplasty were excluded. This review was registered in PROSPERO (CRD420251164054).

RESULTS

Pooled analysis showed no statistically significant difference between hydrotherapy and land-based or usual-care rehabilitation in Visual Analogue Scale (VAS)-measured pain (MD ≈ -0.35; 95% CI [-1.06, 0.36]; p=0.34) or in WOMAC pain (MD ≈ -0.46; 95% CI [-8.50, 7.58]; p=0.89). In contrast, hydrotherapy produced a moderate, statistically significant improvement in lower-limb muscle strength (Hedges' g=0.46; 95% CI [0.23, 0.69]), particularly in knee extensor and hip abductor strength. Heterogeneity was low for VAS pain and muscle strength but substantial for WOMAC pain (I2≈71%), and no evidence of publication bias was identified.

CONCLUSIONS

Hydrotherapy did not reduce postoperative pain more than land-based exercise or usual care; pain relief was comparable between approaches, whereas hydrotherapy yielded greater gains in muscle strength. Heterogeneity in treatment parameters and the limited number of high-quality trials preclude definitive conclusions; future research should standardize hydrotherapy protocols and investigate long-term outcomes.