Lumbar Repositioning Accuracy as a Measure of Proprioception in Patients with Back Dysfunction and Healthy Controls

STUDY DESIGN: A control group cross-sectional design. PURPOSE: To compare the difference in repositioning accuracy, as a measure of lumbar proprioception, between patients with back dysfunction and healthy subjects. OVERVIEW OF LITERATURE: Evidence suggests that spinal stability might be compromised in patients with back dysfunction. Lumbar proprioception in back dysfunction has not, however, been adequately investigated. METHODS: Forty-five participants, representing three groups, took part in the study. Subjects in group one (n = 15) were healthy subjects. Subjects in group two (n = 15) had a history of non-specific mechanical back dysfunction, while subjects in group three (n = 15) had discogenic back dysfunction. Subjects were required to reproduce a target position of 30° lumbar flexion and the absolute error (AE) was calculated. RESULTS: The AEs between target and reproduced positions were calculated. The average repositioning AEs were 2.8, 7.5, and 7.1° for the control, mechanical, and discogenic back dysfunction groups respectively. Analysis of variance revealed significant difference between the three groups (p < 0.0002). The AEs were greater in the two back dysfunction groups compared to the control group. Post-hoc tests revealed significant difference in AEs between the control and mechanical group (p < 0.0003), and discogenic group (p < 0.0001), while there was no significant difference between the mechanical and discogenic back dysfunction groups (p = 0.73). CONCLUSIONS: Differences in proprioception do exist between subjects with back dysfunction and normal subjects. The proprioceptive deficits do exist regardless of the cause of the back dysfunction, and may represent an important aspect of the patho-physiology of such a condition.