Does a knee joint position sense test make functional sense? Comparison to an obstacle clearance test following anterior cruciate ligament injury.

OBJECTIVES

To evaluate knee joint position sense (JPS) among individuals with anterior cruciate ligament reconstruction (ACLR), cleared for return to sport, and investigate whether JPS errors are associated with outcomes of a functional obstacle clearance test (OC; downward vision occluded).

DESIGN

Cross-sectional.

SETTING

Controlled laboratory.

PARTICIPANTS

Thirty-four individuals following ACLR, 23 non-athletic asymptomatic controls (CTRL), 18 athletes (ATH).

MAIN OUTCOME MEASURES: absolute error (AE) and variable error (VE) for weight-bearing knee JPS (target angles: 40°, 65°); minimal distances of the lower extremity from the obstacle (at any time and vertical clearance; two obstacle heights).

RESULTS

Larger AE (P = 0.023) and VE (P = 0.010) were observed for CTRL compared with ACLR. CTRL also had larger OC distances for the trailing leg compared with ATH (P ≤ 0.046) and greater variability compared to both other groups (P ≤ 0.033). Moderate positive correlations (Rs ≥ 0.408, P ≤ 0.029) were observed between AE for the 40° angle and low-obstacle distances, for the injured ACLR leg.

CONCLUSIONS

Knee JPS was worse in less-active individuals rather than following ACLR. Functional assessments like our OC test should complement isolated JPS tests, as they emphasize whole-body coordination and thus constitute more relevant estimations of proprioception.