Knee Joint Position Sense in Knee Osteoarthritis

Knee proprioception plays a critical role in joint stability, movement control, and the accurate perception and reproduction of joint position. In individuals with knee osteoarthritis (OA), alterations in joint structures, mechanoreceptor function, pain, and sensorimotor control may compromise joint position sense and increase errors during active joint position reproduction. However, proprioceptive performance is not solely determined by disease-related changes and may also be influenced by the conditions under which proprioception is assessed.

Both visual input and body position may influence proprioceptive performance. Visual information can provide additional sensory cues that support joint position estimation, whereas the absence of visual information may increase reliance on somatosensory and proprioceptive afferent input. Body position may also modify proprioceptive performance by altering gravitational demands, muscle activation patterns, joint loading, and sensory information arising from muscles and periarticular structures. Therefore, differences in joint position reproduction between testing conditions may reflect the combined influence of visual and positional factors rather than the isolated contribution of either factor.

Despite the clinical relevance of knee joint position sense, it remains unclear whether proprioceptive performance obtained under different visual and positional testing conditions is comparable and whether the response to these conditions differs between individuals with and without knee OA. Examining these condition-dependent differences may contribute to a better understanding of how proprioceptive assessment protocols influence measured joint position sense and may facilitate the interpretation and standardization of proprioceptive assessments.

Accordingly, the primary aim of this study was to compare absolute angular error during active knee joint position reproduction from 90° to 30° of knee flexion between individuals with and without knee OA under two different testing conditions: sitting with visual input and prone without visual input. A secondary aim was to investigate whether age and pain intensity were associated with proprioceptive error in individuals with knee OA.

Inclusion criteria

• Age between 40 and 80 years,
• A confirmed diagnosis of knee osteoarthritis,
• Absence of any health condition that could interfere with the measurement procedures.

Exclusion criteria

• Refusal to participate in the study,
• Presence of a diagnosed neurological disorder that could affect the measurements,
• Presence of cardiopulmonary instability that could influence the measurements,
• History of knee-related trauma within the past year,
• Receipt of physiotherapy or rehabilitation treatment within the past year,
• History of knee-related surgery,
• Inability to follow verbal instructions due to insufficient cognitive function.