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/cm² (95% CI 0.2 to 2.2), CMC joint by 1.2kg/cm² (95% CI 0.5 to 2.0), scaphoid bone by 1.0kg/cm² (95% CI 0.2 to 1.8) and hamate bone by 1.9kg/cm² (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.