The relationship between vibratory perception and joint position sense testing at the knee

Abstract

Background: Proprioception may be defined as a specialised sensory modality that gives information about joint position sense (JPS), kinaesthesia and vibratory perception. Vibratory Perception Threshold (VPT) testing has been suggested as an alternative means for assessing proprioception at the knee, as it is believed to travel through the same type of large afferent nerve fibres as JPS. Methods: This study examines the strength of relationship between vibration sense and JPS at the knee in healthy participants and determines the minimum number of trials required for each method to attain constant stable data. Stability was determined by 3 consecutive cumulative standard deviations varying less than 5%. Twenty healthy adults (11 females, 9 males) were tested for VPT at five lower limb positions and JPS at two angles of knee flexion (20° and 60°) using Active Angle Reproduction (AAR). Results: Results showed no significant correlations between VPT and JPS, suggesting the two modalities measure different facets of proprioception. VPT (at all 5 sites) and AAR 20° required 4 repetitions to attain data stability, whereas AAR 60° required five repetitions. There were significant differences (p<0.005) between the five sites tested for VPT with increasing thresholds at more proximal sites. No significant differences were seen between the two angles tested for JPS. Conclusions: The two testing modalities are not interchangeable when testing proprioception, requiring at least 4 repetitions to attain consistent stable data. These findings have implications for clinicians and researchers, encouraging the use of broader proprioceptive assessments and increased repetitions.