Are physical factors associated with poor prognosis following a whiplash trauma?: a systematic review


The aim of this systematic review was to summarise and synthesis the current evidence regarding the predictive ability of physical factors in individuals with acute whiplash Associated Disorders (WAD) transitioning to chronic WAD.


Several electronic databases were searched by two independent reviewers including MEDLINE, Embase, CINAHL, PsycINFO, Scopus and Web of Science as well as grey literature. Observational cohort studies were included if they involved participants with acute WAD followed for at least 3 months post-injury. Cohort studies were also required to assess the predictive ability of one or more physical factors that directly involve a body function and/or structure that can be measured objectively. Patient-reported outcomes of physical function were also considered as physical factors. Neck Disability Index was considered as the primary outcome while all other validated measures were considered as secondary outcomes. Two independent reviewers extracted the data and assessed the risk bias across individual studies using the Quality In Prognostic Studies tool.


Results: The literature search revealed 12774 potential studies, of which 12 studies (11 cohorts) were included in this review. Three studies were assessed as having low risk of bias, three studies as moderate risk of bias, and six studies as high risk of bias, mainly due to limitations in study attrition domain, not adjusting for important confounders, insufficient details for the statistical analysis, and/or poor reporting. Meta-analysis was not feasible due to the small number of included studies and the heterogeneity in the prognostic factors and outcomes, and therefore a qualitative synthesised was adopted. Several physical factors were considered by eligible studies including, neck range of motion, joint position error, neck pain and disability, muscle strength/endurance, superficial neck flexor muscle activity, physical function, and WAD classification. Four studies showed that WAD grade II and grade III were significantly predictive of poor outcomes 6 months after injury, when compared grade I or grade 0. Other physical factors such as neck joint position error, neck muscle strength/endurance, neck flexor muscle activity and functional status at baseline were not associated with poor outcomes 6 months after injury. Conflicting evidence was found with the regards to the predictive ability of baseline neck range of motion on poor outcomes following injury.

Conclusion(s): There was limited evidence of low quality showing that higher WAD classification could predict poor outcome in patients with acute WAD. Most of the eligible studies were high risk of bias.

Cost and savings

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Patients with acute WAD could be categorised based on WAD grade into low risk and high risk of developing persistent symptoms. Intervention should be aimed at people with high WAD grade which could reduce their risk of experiencing chronic symptoms, informing health policy and clinical management.

Top three learning points

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Funding acknowledgements

No grant for this research was received from any funding agency in the public, commercial or not-for- profit sectors.