Assessment of a continuous passive motion assistive device in dogs following stifle surgery

Canine rehabilitation optimizes recovery and the quality of life in dogs with musculoskeletal conditions or after surgery. Achieving proper range of motion (ROM) is vital post-stifle surgery, often accomplished through manual therapy and active exercises. We investigated the mechanical performance of a continuous passive motion (CPM) device for dogs and its potential use in canine rehabilitation therapy.

In the ethical review process, our research was accepted to be evaluated in a sample of four dogs that had undergone left stifle surgery. Each dog underwent four sessions with the device at three different speeds. Results showed the device replicated extension angles close to goniometer measurements used in manual therapy. Flexion was also achieved, but not to the same extent. A force threshold stopped the device, avoiding discomfort in dogs with restricted ROM. Dog-specific factors like body position, opposition to movement, limb size, stage of recovery, haircoat, and discomfort, appeared to influence device operation. Mechanical improvements to allow for enhanced flexion are recommended in future CPM device designs, including a resistance threshold that could be adjusted for individual dogs and stages of healing. This study serves as a foundation for future advancements in canine rehabilitation systems. A canine CPM device may provide an affordable option to improve ROM. This could be beneficial for dog owners, who may not be comfortable with manual therapy, to assist with home rehabilitation exercises.