The increase in the prevalence of osteoarthritis (OA) with age may be due in part to increased joint load resulting from age-related declines in neuromechanical factors, including joint position sense or proprioception. Several studies have demonstrated that knee proprioception is worse in knee OA patients versus age-matched control subjects. Functional consequences of impaired proprioception may include lower gait velocity, shorter stride length, and slower stair walking time. Some studies have shown that proprioception can be enhanced by wearing an elastic bandage or similar orthoses and by muscle training. A variety of other interventions have been proposed as well. To date studies of proprioception in OA patients have been cross-sectional. Theoretically, impaired proprioception might contribute toward or result from OA. A paradigm depicting directions in the relationship between proprioception impairment and OA is offered. Longitudinal data are badly needed to elucidate cause and effect and to determine the relative importance of impaired proprioception in disease progression. The relationship between sensory input and protective or damaging muscle activity has been minimally evaluated in the setting of OA. In studies of clinical conditions related to OA, experimental effusions had no effect on proprioception. Proprioception was worse in hypermobility syndrome patients versus age-matched controls. Anterior cruciate ligament insufficiency is associated with a decline in proprioception.