Joint position sense error in the hip and knee without reference to the joint angle.

Background: Joint position reproduction measures the angle acuity of reference angle reproduction using an indicator angle. However, reference angles are often not available.

Objective: This study aimed to examine joint position sense at three different targeted joint angles, which were estimated from the maximum range of motion (maxROM) without a reference angle at each targeted joint angle.

Methods: The maxROM was measured in straight leg raise (SLR) and active knee extension (AKE) positions. In both positions, a targeted joint angle at 75% of the maxROM was assessed first, followed by that at 50% and 25% of the maxROM. A one-sample t-test was used to analyze differences between the targeted and reproduced angles in both positions.

Results: All reproduced angles significantly differed from the targeted angle in both SLR and AKE positions except for the reproduced angle measured at 75% maxROM. Overall, position errors in the AKE position were higher than those in the SLR position.

Conclusions: Estimating the angle based on the maxROM without a matched reference angle may lead to significant discrepancies in comparison with the targeted joint angle. In clinical settings, if accurate reproduction of motions is required to improve proprioception, providing a reference angle might be helpful.