Radial nerve mobilisation had bilateral sensory effects in people with thumb carpometacarpal osteoarthritis: a randomised trial.

QUESTION In people with thumb carpometacarpal osteoarthritis, does radial nerve mobilisation to the affected hand reduce pressure pain sensitivity in the contralateral hand? DESIGN Secondary analysis of data from a randomised trial with concealed allocation, assessor blinding, and intention-to-treat analysis. PARTICIPANTS Sixty people with thumb CMC osteoarthritis in the dominant hand aged 70-90 years. INTERVENTIONS The experimental group received sliding mobilisation of the radial nerve and the control group received a non-therapeutic dose of intermittent ultrasound, on the affected side for six sessions over four weeks. OUTCOME MEASURES On the contralateral side, pressure pain thresholds at the lateral epicondyle, thumb CMC joint, tubercle of the scaphoid bone, and hamate bone were assessed before and after the intervention with follow-up at 1 and 2 months. RESULTS No important baseline differences were noted between groups. At the end of the intervention period, the experimental group had significantly a higher (ie, better) pressure pain threshold than the control group at the lateral epicondyle by 1.5kg/cm(2) (95% CI 0.2 to 2.2), CMC joint by 1.2kg/cm(2) (95% CI 0.5 to 2.0), scaphoid bone by 1.0kg/cm(2) (95% CI 0.2 to 1.8) and hamate bone by 1.9kg/cm(2) (95% CI 1.0 to 2.7). Although mean values in the experimental group remained better than the control group at all sites at both follow-up assessments, these differences were not statistically significant. CONCLUSION Radial nerve gliding applied to the symptomatic hand induced hypoalgesic effects on the contralateral hand in people with CMC osteoarthritis, suggesting bilateral hypoalgesic effects of the intervention.