The rehabilitation of knees following anterior cruciate ligament (ACL) injuries has always been more complex than many think. Those who have experienced one injury are 30 to 40 times more likely to suffer a second ACL injury. Equally as disappointing is the fact that only 62-74% of those injured return to their sport following their first injury. Finding and implementing the best rehabilitation methods for ACL injuries is an important task many physical therapists seek answers to. An exciting and enlightening study recently published by the Journal of Orthopedic and Sports Physical Therapy has suggested a potential cause for the increased second injury rates.
The study compared functional magnetic resonance imagining brain scans of healthy, non-injured individuals to those of individuals who had suffered an ACL injury while straightening and bending their knees. The researchers noticed differences between the two groups in the area of the brain that controls leg movement. The noted differences seemed to display as a fundamental change in the way our brains receive information from the knee joint. In healthy knees, it's natural to rely on sensory information from the joint itself, called spatial awareness, to instinctually move. The ability to control your limbs via this feedback mechanism is very important to athletes. It's one of the ways that they're able to perform jumping, landing, cutting, and all the other movements they need to do without injury. However, the brain scans of the injured individuals in this study showed that they relied more on their visual systems (what they could see) than on their joint's spatial awareness. This is important because athletes need to be able to focus their attention elsewhere in order to maximize their performance. As an example, think about how your gait speed and confidence decrease when you enter a dark room. This is because your visual feedback to the brain is reduced in the darkness. Similarly, tracking a ball or opponent during athletics decreases visual feedback of the athlete's lower limb performance, and could lead to decreased athletic performance and confidence as a result.
The good news is that the way our brains receive feedback is adaptable through a process known as neuroplasticity. Through specific training methods that we routinely utilize in our physical therapy department, it's actually possible to train your brain to better utilize the spatial awareness feedback of how your joint is moving. Our goal is always to help our patients return to their prior levels, if not even improve, and as a result we often involve their sport tasks into the rehabilitation process. This allows them to "hit the ground running" when the time comes.