Your Dog’s Knee Injury Causes Brain Issues, and Overuse of the Eyes! Say What???
30 Dec 2022
By Laurie Edge-Hughes
Bachelor of Science in Physical Therapy
Master of Animal Studies in Animal Physiotherapy
Certificate in Canine Rehabilitation Therapist
Certified by the Acupuncture Foundation of Canada Institute
Certificate in Small Animal Acupuncture / Dry Needling
Cruciate injuries in the knee occur in both people and dogs. They pose similar problems after injury or after surgery: pain; swelling; gait modifications; osteoarthritis; and loss of strength (to name a few). But, did you know that trauma to the cruciate ligament has also been show to alter body awareness and reaction times? Cruciate ligament injuries may result in neuroplastic changes (i.e. nerve receptors, nerves, spinal cord, brain, and the messaging between these structures) due to lost information receptors of the damaged cruciate ligament and subsequent compensations in body awareness and control. More and more human studies have reported unresolved neuroplastic changes after injury, surgery, and rehabilitation that may limit function and return to sports participation.
What does that mean?
It means that the injury to the knee ligament(s) resulted in abnormal information (and reduced information) going to the brain, how the brain was processing the information was not typical, and the output (instructions) from the brain were subsequently inaccurate as well! The ‘wiring issues’ (i.e. the nervous system not providing proper body awareness) after a cruciate injury with or without surgery can hinder an animal’s safe use of that leg without targeted rehabilitation to address the ’wiring issues’ especially when it comes to sports and higher levels of function.
A 2017 study provided information about what happens in the brain after a cruciate surgery. Researchers from Ohio State University did a study where they used MRI to look at the brains of patients following a cruciate repair surgery and a group of normal (uninjured) participants as they repeatedly flexed and extended their knees. What they found was that participants who had undergone knee surgery had increased activation in the contralateral motor cortex, lingual gyrus, and ipsilateral secondary somatosensory area and diminished activation in the ipsilateral motor cortex and cerebellum when compared to healthy matched controls.
We all need a visual after that last sentence!!!
Simply stated, the knee-surgery group was using (or trying to use) additional pathways (i.e. visual –motor in particular) in order to competently do the movement, as their normal (sensory-motor pathways) were diminished. This means that the body was not producing or interpreting signals coming from the knee or leg as well as it could or should and instead was relying on visual cues (the eyes) give feedback to the brain about the movement at the knee joint.
Okay, Okay, I hear you saying, “So, what do we do with this information?”
Here are my answers to that question:
1) Because we know the patient (dog or human) is now more reliant on visual postural cues, we would do well to get them to visually focus on something as they are doing a task. Fortunately for us in canine rehab, most of our exercise enticement also included cookies or treats… and this may actually be beneficial for visual-motor retraining!
2) I like to take dogs to an end-stage of rehab where I make them navigate objects while creating strong muscular contractions in the legs (i.e. playing tug of war through and obstacle course or while going back and forth over a plank.) The strong muscle contraction serve to increase information coming from the leg muscles, thus increasing messages to the brain.
3) Educate owners of dogs with cruciate injuries who also have vision issues, that their dog may have slower return to function or may have more long-term issues than a dog with full vision.
4) Eventually practice more tasks while removing visual feedback. I like backing up exercises. Backing up straight line on a flat surface, then an unstable surface, then over obstacles, and then finally while backing up and stepping off of a surface onto an unstable surface (i.e. backing up from a platform onto an inflatable peanut or soft irregular surface.
5) Perhaps include exercises of balance or movement with the dog blindfolded (safely supervised of course) to work on re-establishing information pathways between the muscles, joints and the brain.
I hope there are other science-nerds in the crowd! I find this information fascinating and I hope you do as well. Here at The Canine Fitness Centre Ltd. we like to stay up to date on research and are always extrapolating from what is in the human literature to help us stay at the forefront of new ways to help your dog!
Grooms DR, et al. Neuroplasticty associated with anterior cruciate ligament reconstruction. J Orthop Sports Phys Ther. 2017 Mar;47(3):180-189.
Erson Religioso III, What is My Inferior Temporal Gyrus? And Why Haven’t I Up-Trained This Mother for my ACL Clients?
accessed June 21, 2017.