Neck-specific exercise with or without a behavioural approach, or prescription of physical activity in chronic whiplash associated disorders

Abstract: Background: Although 50% of those who suffer a whiplash injury still report neck pain after one year, there is a lack of knowledge about effective treatment for chronic whiplash associated disorders (WAD). Exercise is potentially useful, but the response to exercise in chronic WAD is highly variable between individuals and factors associated with good outcomes as well as the cost-effectiveness are unknown.Aim: The general aim of this thesis was to evaluate the effect on  self-reported disability/ functioning, pain and selfefficacy of three different exercise interventions in chronic WAD grade 2 and 3, and to determine the cost-effectiveness of these interventions.Material and methods: A total of 216 participants with chronic WAD took part in this randomized, assessor blinded, controlled, clinical trial. Participants were randomized to either neck-specific exercise without (NSE), or with a behavioural approach (NSEB), or prescription of physical activity (PPA) for 12 weeks. Evaluations of change scores and proportion of clinically relevantly improved participants regarding disability/functioning (Neck Disability Index (NDI)/Patient Specific Functional Scale (PSFS)), pain (Visual Analogue Scale of current neck pain (VAS-P), pain bothersomeness (VAS-B)) and Self-efficacy (Self-Efficacy Scale (SES)) were made after 3, 6, 12 and 24 months. Secondary analyses were made, regarding factors associated with clinically relevant improvements in disability, pain and regarding cost-effectiveness.Results: Disability was more improved in the NSE/NSEB groups (NDI, P=0.02) than the PPA group, which reported no improvement, at 3 and 6 months, results remaining at 12 and 24 months (p ≤ 0.02). Functioning (PSFS) was also more improved in the NSE/NSEB groups than the PPA group at 3 months, in the NSEB compared to the PPA group at 6 months, and the NSE compared to the PPA groups at 12 and 24 months. The proportion of participants reaching clinically relevant improvement regarding NDI and PSFS was also larger in the NSE/NSEB groups at all time points (P<0.05), except NDI at 3 months and PSFS at 24 months. There were no differences between groups in VAS-P, VASB or SES change scores. The proportion of participants with clinically relevant reduction in VAS-P and VAS-B was however higher (P<0.02) in the NSE/NSEB groups compared with the PPA group at 3 and 12 months. Self-efficacy was only improved in the NSE group but without any between-group differences. There were no significant differences in any outcomes between the NSE/NSEB groups.The only significant factor associated with both clinically relevant improvements in disability and neck pain both at 3 and 12 months was participation in the NSE group, with odds up to 5.3 times higher than in the PPA group. Different baseline features were associated with the improvements depending on the outcome and time point examined. From a societal perspective, NSE was the cost-effective option.Conclusion: Physiotherapist-led neck-specific exercise resulted in better outcomes than prescription of physical activity regarding disability, functioning, and pain. The observed benefits of adding a behavioural approach to neck-specific exercise were inconclusive, and NSE was the cost-effective option from a societal perspective. Factors associated with clinically relevant improvements after exercise interventions in chronic WAD differed whether disability or neck pain was the outcome, but also differed in the short and long term. Participation in the NSE group was the only factor associated with both outcomes after both 3 and 12 months.