Effect of a tailor-made hydrotherapy on physical functions in patients after unilateral unicompartmental knee arthroplasty-A feasibility study.

Introduction: Unicompartmental knee arthroplasty (UKA) is one of the treatment options for patients whose osteoarthritis involves one out of the 3 compartments. Patients who underwent UKA benefited from shorter hospital stays, better range of motion, and lower risk of postoperative complications compared with patients who underwent total knee arthroplasty (TKA). Hydrotherapy is being introduced complementary to conventional postoperative rehabilitation programs. No report on the use of hydrotherapy evaluating physical functions on patients who underwent UKA leads us to carry out the present study. This is a feasibility study to investigate the effects of hydrotherapy on physical functions in patients after primary unilateral UKA.

Methods: A retrospective cohort study recruited 68 patients who underwent primary unilateral UKA. Nineteen patients were allocated to the hydrotherapy group and 49 patients were in the convention group. Patients in the hydrotherapy group received hydrotherapy and conventional physiotherapy, and the convention group was given conventional physiotherapy only. The primary outcome was Knee Society Function Score (KFS) measured before surgery, six months, and one year after UKA. Self-reported walking tolerance, Timed Up and Go Test (TUGT), and 30-s Chair Stand Test (30CST) were conducted before and after the completion of rehabilitation. Pain and range of motion were also covered.

Results: Hydrotherapy group showed significantly higher KFS at 6 months (P = 0.038) and one year (P = 0.030) after operation. Range of motion flexion and extension in the hydrotherapy group were significantly improved at postoperative 4 weeks and the last session of rehabilitation. Self-reported walking tolerance in the hydrotherapy group was significantly longer at the last session (P = 0.011). No significant difference was found in TUGT, 30CST, and pain between the two groups after rehabilitation. In both groups, all outcomes were significantly better as compared to preoperative findings.

Conclusion: Patients who underwent UKA after hydrotherapy complementary to conventional physiotherapy showed significant improvements in functions, range of motion, and time to tolerating walking before rest. Pain, mobility, balance, leg strength, and endurance were comparable between the two groups. Combination of hydrotherapy with conventional postoperative physiotherapy rehabilitation yielded even better outcomes than conventional physiotherapy alone. Further research with advanced study design, larger sample size and longer follow-up periods for patients who underwent UKA is recommended.

Trial registration: NCT06459960, retrospectively registered on 13.06.2024 (ClinicalTrials.gov).