Letters to the Editor-in-Chief of JOSPT as follows:

• "Early Prognostic Factors in Patients With Whiplash" and Author's Response
• "Staying Current in the Use of Ultrasound Imaging" and Author's Response
• "Differentiating the Soleus From the Gastrocnemius With the Heel Raise Test" and Author's Response

J Orthop Sports Phys Ther 2011;41(12):983-987. doi:10.2519/jospt.2011.0202

STUDY DESIGN: Longitudinal cohort study. OBJECTIVES: To determine whether pressure pain threshold (PPT), tested at 2 standardized sites, could provide additional prognostic ability to predict short-term outcomes in people with acute whiplash, after controlling for age, sex, and baseline pain intensity. BACKGROUND: PPT may be a valuable assessment and prognostic indicator for people with whiplash-associated disorder. The extent to which PPT can predict short-term disability scores has yet to be explored in people with acute (of less than 30 days in duration) whiplash-associated disorder in a clinical setting. METHODS: Eligible patients were recruited from community-based physiotherapy clinics in Canada. Baseline measurements included PPT, as well as pain intensity, age, and sex. Neck-related disability was collected with the Neck Disability Index 1 to 3 months after PPT testing. Multiple linear regression models were constructed to evaluate the unique contribution of PPT in the prediction of follow-up disability scores. RESULTS: A total of 45 subjects provided complete data. A regression model that included sex, baseline pain intensity, and PPT at the distal tibialis anterior site was the most parsimonious model for predicting short-term Neck Disability Index scores 1 to 3 months after PPT testing, explaining 38.6% of the variance in outcome. None of the other variables significantly improved the predictive power of the model. CONCLUSION: Sex, pain intensity, and PPT measured at a site distal to the injury were the most parsimonious set of predictors of short-term neck-related disability score, and represented promising additions to assessment of traumatic neck pain. Neither age nor PPT at the local site was able to explain significant variance beyond those 3 predictors. Limitations to interpretation are addressed.

J Orthop Sports Phys Ther 2011;41(9):658-665. doi:10.2519/jospt.2011.3668

KEY WORDS: cervical spine, neck, PPT, WAD

STUDY DESIGN: Cross-sectional convenience sample. OBJECTIVES: To describe the distribution of scores for pressure pain threshold (PPT) at 2 standardized testing sites in people with neck pain of less than 90 days' duration: the angle of the upper trapezius and the belly of the tibialis anterior. A secondary objective was to identify important influences on PPT. BACKGROUND: PPT may be a valuable assessment and prognostic indicator for people with neck pain. However, to facilitate interpretation of scores, knowledge of means and variance for the target population, as well as factors that might influence scores, is needed. METHODS: Participants were recruited from community-based physiotherapy clinics and underwent PPT testing using a digital algometer and standardized protocol. Descriptive statistics (mean, standard deviations, quartiles, skewness, and kurtosis) were calculated for the 2 sites. Simple bivariate tests of association were conducted to explore potential moderators. RESULTS: A positively skewed distribution was described for the 2 standardized sites. Significant moderators were sex (male higher than female), age (r = 0.22), and self-reported pain intensity (r = –0.24). Neither litigation status nor most symptomatic/least symptomatic side influenced PPT. CONCLUSIONS: This manuscript presents information regarding the expected scores for PPT testing in people with acute or subacute neck pain. Clinicians can compare the results of individual patients against these population values, and researchers can incorporate the significant confounders of age, sex, and self-reported pain intensity into future research designs.

J Orthop Sports Phys Ther 2011;41(9):651-657. doi:10.2519/jospt.2011.3667

KEY WORDS: algometry, cervical pain, hyperalgesia, hypersensitivity, whiplash

STUDY DESIGN: Clinical measurement. OBJECTIVES: To evaluate the intrarater, interrater, and test-retest reliability of an accessible digital algometer, and to determine the minimum detectable change in normal healthy individuals and a clinical population with neck pain. BACKGROUND: Pressure pain threshold testing may be a valuable assessment and prognostic indicator for people with neck pain. To date, most of this research has been completed using algometers that are too resource intensive for routine clinical use. METHODS: Novice raters (physiotherapy students or clinical physiotherapists) were trained to perform algometry testing over 2 clinically relevant sites: the angle of the upper trapezius and the belly of the tibialis anterior. A convenience sample of normal healthy individuals and a clinical sample of people with neck pain were tested by 2 different raters (all participants) and on 2 different days (healthy participants only). Intraclass correlation coefficient (ICC), standard error of measurement, and minimum detectable change were calculated. RESULTS: A total of 60 healthy volunteers and 40 people with neck pain were recruited. Intrarater reliability was almost perfect (ICC = 0.94-0.97), interrater reliability was substantial to near perfect (ICC = 0.79-0.90), and test-retest reliability was substantial (ICC = 0.76-0.79). Smaller change was detectable in the trapezius compared to the tibialis anterior. CONCLUSIONS: This study provides evidence that novice raters can perform digital algometry with adequate reliability for research and clinical use in people with and without neck pain.

J Orthop Sports Phys Ther 2011;41(9):644-650. doi:10.2519/jospt.2011.3666

KEY WORDS: algometer, cervical spine, PPT, tibialis anterior

STUDY DESIGN: Systematic review of clinical measurement. OBJECTIVE: To find and synthesize evidence on the psychometric properties and usefulness of the neck disability index (NDI). BACKGROUND: The NDI is the most commonly used outcome measure for neck pain, and a synthesis of knowledge should provide a deeper understanding of its use and limitations. METHODS AND MEASURES: Using a standard search strategy (1966 to September 2008) and 4 databases (Medline, CINAHL, Embase, and PsychInfo), a structured search was conducted and supplemented by web and hand searching. In total, 37 published primary studies, 3 reviews, and 1 in-press paper were analyzed. Pairs of raters conducted data extraction and critical appraisal using structured tools. Ranking of quality and descriptive synthesis were performed. RESULTS: Horizon estimation suggested the potential for 1 missed paper. The agreement between raters on quality assessments was high(kappa = 0.82). Half of the studies reached a quality level greater than 70%. Failures to report clear psychometric objectives/hypotheses or to rationalize the sample size were the most common design flaws. Studies often focused on less clinically applicable properties, like construct validity or group reliability, than transferable data, like known group differences or absolute reliability (standard error of measurement [SEM] or minimum detectable change [MDC]). Most studies suggest that the NDI has acceptable reliability, although intraclass correlation coefficients (ICCs) range from 0.50 to 0.98. Longer test intervals and the definition of stable can influence reliability estimates. A number of high-quality published (Korean, Dutch, Spanish, French, Brazilian Portuguese) and commercially supported translations are available. The NDI is considered a 1-dimensional measure that can be interpreted as an interval scale. Some studies question these assumptions. The MDC is around 5/50 for uncomplicated neck pain and up to 10/50 for cervical radiculopathy. The reported clinically important difference (CID) is inconsistent across different studies ranging from 5/50 to 19/50. The NDI is strongly correlated (>0.70) to a number of similar indices and moderately related to both physical and mental aspects of general health. CONCLUSION: The NDI has sufficient support and usefulness to retain its current status as the most commonly used self-report measure for neck pain. More studies of CID in different clinical populations and the relationship to subjective/work/function categories are required.

Note: Appendix B is online-only and is included in this downloadable PDF.

J Orthop Sports Phys Ther 2009;39(5):400-417. doi:10.2519/jospt.2009.2930

KEY WORDS: cervical spine, outcome measure, reliability, validity

STUDY DESIGN: Systematic review and meta-analysis. BACKGROUND: Whiplash-associated disorder (WAD) is the most common reported injury following motor vehicle accident. Evidence for prognosis and intervention are difficult to interpret due to differences in inception times, outcomes used, and sample heterogeneity. METHODS: An extensive literature search was conducted to identify published studies of prognosis following whiplash. Rigorous inclusion criteria were applied to allow for meaningful results to be drawn. Data were extracted, transformed where necessary, and pooled to allow estimation of the odds ratio for any factor with at least 3 data points in the literature. RESULTS: From 11 cohorts (n = 3193), 25 factors were identified with at least 3 data points in the existing literature. Of these, 9 were found to be significant predictors based on the odds ratio and confidence limits: no postsecondary education, female gender, history of previous neck pain,baseline neck pain intensity greater than 55/100, presence of neck pain at baseline, presence of headache at baseline, catastrophizing, WAD grade 2 or 3, and no seat belt in use at time of collision. Neck pain intensity, WAD grade, headache, and no postsecondary education were robust to publication bias. CONCLUSIONS: Using a rigorous process for the identification and extraction of data from a homogenous subset of the prognostic WAD literature, we were able to identify several factors for which information is easy to collect clinically and could provide clinicians with a good sense of prognosis following whiplash injury. LEVEL OF EVIDENCE: Prognosis, level 1a.

J Orthop Sports Phys Ther 2009;39(5):334-350, Epub 18 July 2008. doi:10.2519/jospt.2009.2765

KEY WORDS: cervical spine, neck, prognosis, WAD, whiplash-associated disorder