Effectiveness of underwater treadmill rehabilitation following femoral head and neck ostectomy in dogs: A prospective controlled pilot study.

Background and Aim: Femoral head and neck ostectomy (FHO) is a widely performed salvage procedure for canine coxofemoral disorders; however, postoperative recovery is frequently limited by reduced weight bearing, persistent lameness, muscle atrophy, and restricted hip mobility. Although underwater treadmill (UWTM) rehabilitation has been used for various orthopedic conditions, objective evidence supporting its effectiveness after FHO remains limited. This study aimed to evaluate the effectiveness of a standardized 10-session UWTM rehabilitation protocol on functional recovery in dogs after FHO, using clinical and objective gait assessment measures. Materials and Methods: A prospective controlled pilot study was conducted using 10 client-owned dogs that underwent unilateral FHO. Dogs were allocated to either a UWTM rehabilitation group (n = 5) or a non-UWTM control group (n = 5). One dog in the UWTM group was withdrawn due to force plate noncompliance, leaving four treatment and five control dogs to complete the 12-week follow-up. Rehabilitation consisted of 10 weekly UWTM sessions initiated approximately 3 weeks after surgery. Clinical evaluations included lameness and pain scores, thigh circumference, and force plate kinetic gait analysis. Peak vertical force (PVF) normalized to body weight (BW) served as the primary objective outcome measure. Assessments were performed at postoperative weeks 4, 8, and 12. Results: Dogs receiving UWTM rehabilitation demonstrated significant improvements in functional recovery over time. Lameness scores decreased significantly between postoperative months 1 and 3 (mean difference = 2.00 points, p < 0.05), while PVF of the operated limb increased significantly by 23.66% of BW between months 1 and 3 (p < 0.05). Interlimb PVF asymmetry also decreased significantly in the UWTM group. In contrast, the control group showed significant improvement only in lameness score by month 3, whereas PVF did not change significantly throughout the study. Pain scores and thigh circumference did not differ significantly between groups over time. No serious treatment-related adverse events were observed during the rehabilitation protocol. Conclusion: A standardized 10-session UWTM rehabilitation protocol may accelerate postoperative functional recovery following FHO by improving limb weight bearing and reducing lameness without treatment-related complications. Although these preliminary findings support UWTM as a promising adjunctive rehabilitation strategy after FHO, the small sample size and pilot design limit generalizability. Larger randomized controlled trials with extended follow-up are warranted to establish optimal rehabilitation protocols and confirm long-term clinical benefits.