Impaired joint proprioception in patients with cervical myelopathy

Study Design. Prospective clinical study. Objectives. To evaluate impairment of proprioception quantitatively in patients with cervical myelopathy. Summary of Background Data. Sensory information regarding proprioception ascends through the posterior columns in the spinal cord. Damage to these columns causes proprioceptive loss in patients with spondylotic myelopathy. Nevertheless, there have been few studies regarding proprioception in patients with myelopathy. Methods. The authors evaluated knee proprioception in 54 cervical myelopathy patients and compared results with those of 54 age-matched healthy volunteers. Knee proprioception was assessed by joint position sense, represented by the error angles when patients reproduced predetermined angles of knee flexion. Results. The average absolute angle error of right and left knee with the predetermined position of 30degrees of knee flexion was 2.5 +/- 1.8 (mean +/- standard deviation) and 1.8 +/- 1.2degrees and with the predetermined 60degrees of flexion, 4.7 +/- 2.8 and 2.8 +/- 1.4degrees in the myelopathy and control groups, respectively. The average absolute angular errors in the myelopathy group were significantly higher than those in the control group for each predetermined knee position (P < 0.01). Conclusions. Proprioceptive ability is impaired in patients with cervical myelopathy. Position sense can be assessed by measuring the angular error when reproducing criterion positions, and the results may reflect the severity of cervical myelopathy. Thus, the present method of measuring proprioception is easy to perform and useful for quantitative assessment of the severity of cervical myelopathy.