**Abstract**

Proprioception considered as the obtaining of information about one's own action does not necessarily depend on proprioceptors. At the knee joint, perceptual systems are active sets of organs designed to reach equilibrium through synergies. Many surgical procedures, such as ACL reconstruction in personalized medicine, are often based on native anatomy, which may not accurately reflect the proprioception between native musculoskeletal tissues and biomechanical artifacts. Taking an affordance-based approach to this type of "design" brings valuable new insights to bear in advancing the area of "evidence-based medicine (EBM)." EBM has become incorporated into many health care disciplines, including occupational therapy, physiotherapy, nursing, dentistry, and complementary medicine, among many others. The design process can be viewed in terms of action possibilities provided by the (biological) environment. In anterior crucial ligament (ACL) reconstruction, the design goal is to avoid ligament impingement while optimizing the placement of the tibial tunnel. Although in the current rationale for tibial tunnel placement, roof impingement is minimized to avoid a *negative* affordance, we show that tibial tunnel placement can rather aim to constrain the target bounds with respect to a *positive* affordance. We describe the steps for identifying the measurable invariants in the knee proprioception system and provide a mathematical framework for the outcome measure within the knee.

**Keywords:** knee proprioception, knee-tensegrity-structure (KTS), affordancebased-design, ACL impingement, knee synergy, entrainment, instantaneous knee screw (IKS)
