Proprioception, the ability to perceive one's own actions, is not solely dependent on proprioceptors. Perceptual systems at the knee joint work together to achieve balance through synergies. However, surgical procedures like ACL reconstruction often rely on native anatomy, which may not accurately reflect the interaction between musculoskeletal tissues and biomechanical artifacts. Taking an affordance-based approach to design in evidence-based medicine (EBM) can provide valuable insights. EBM has been integrated into various healthcare disciplines, including occupational therapy, physiotherapy, nursing, dentistry, and complementary medicine. The design process can be understood in terms of the action possibilities offered by the biological environment. In ACL reconstruction, the goal is to optimize tibial tunnel placement while avoiding ligament impingement. Instead of solely minimizing roof impingement, we propose considering tibial tunnel placement as a means to constrain the target bounds based on positive affordance. We outline the steps for identifying measurable invariants in the knee proprioception system and present a mathematical framework for measuring outcomes within the knee.