We present a systematic review of prospective cohort studies. Our aim was to assess prognostic factors associated with functional recovery of patients with whiplash injuries. The failure of some patients to recover following whiplash injury has been linked to a number of prognostic factors. However, there is some inconsistency in the literature and there have been no systematic attempts to analyze the level of evidence for prognostic factors in whiplash recovery. Studies were selected for inclusion following a comprehensive search of MEDLINE, EMBASE, CINAHL, the database of the Dutch Institute of Allied Health Professions up until April 2002 and hand searches of the reference lists of retrieved articles. Studies were selected if the objective was to assess prognostic factors associated with recovery; the design was a prospective cohort study; the study population included at least an identifiable subgroup of patients suffering from a whiplash injury; and the paper was a full report published in English, German, French or Dutch. The methodological quality was independently assessed by two reviewers. A study was considered to be of 'high quality' if it satisfied at least 50% of the maximum available quality score. Two independent reviewers extracted data and the association between prognostic factors and functional recovery was calculated in terms of risk estimates. Fifty papers reporting on twenty-nine cohorts were included in the review. Twelve cohorts were considered to be of 'high quality'. Because of the heterogeneity of patient selection, type of prognostic factors and outcome measures, no statistical pooling was able to be performed. Strong evidence was found for high initial pain intensity being an adverse prognostic factor. There was strong evidence that for older age, female gender, high acute psychological response, angular deformity of the neck, rear-end collision, and compensation not being associated with an adverse prognosis. Several physical (e.g. restricted range of motion, high number of complaints), psychosocial (previous psychological problems), neuropsychosocial factors (nervousness), crash related (e.g. accident on highway) and treatment related factors (need to resume physiotherapy) showed limited prognostic value for functional recovery. High initial pain intensity is an important predictor for delayed functional recovery for patients with whiplash injury. Often mentioned factors like age, gender and compensation do not seem to be of prognostic value. Scientific information about prognostic factors can guide physicians or other care providers to direct treatment and to probably prevent chronicity.

Objective To review the effectiveness of exercise therapy in patients with osteoarthritis (OA) of the hip or knee. Methods A computerized literature search of Medline, Embase, and Cinahl was carried out. Randomized clinical trials on exercise therapy for OA of the hip or knee were selected if treatment had been randomly allocated and if pain, self‐reported disability, observed disability, or patient's global assessment of effect had been used as outcome measures. The validity of trials was systematically assessed by independent reviewers. Effect sizes and power estimates were calculated. A best evidence synthesis was conducted, weighting the studies with respect to their validity and power. Results Six of the 11 assessed trials satisfied at least 50% of the validity criteria. Two trials had sufficient power to detect medium‐sized effects. Effect sizes indicated small‐to‐moderate beneficial effects of exercise therapy on pain, small beneficial effects on both disability outcome measures, and moderate‐to‐great beneficial effects according to patient's global assessment of effect. Conclusion There is evidence of beneficial effects of exercise therapy in patients with OA of the hip or knee. However, the small number of good studies restricts drawing firm conclusions.

The purpose of this narrative review is to analyze the available literature concerning central sensitization and altered central pain processing in patients with chronic low back pain (LBP). Literature was screened using several electronic search databases. Additional literature was obtained by reference tracking and expert consultation. Studies evaluating central pain processing in conservatively treated patients with chronic LBP were included. Results of studies examining the responsiveness to various stimuli in patients with chronic LBP are conflicting. Some studies in patients with chronic LBP have demonstrated exaggerated pain responses after sensory stimulation of locations outside the painful region, while other studies report no differences between patients and healthy subjects. Studies examining the integrity of the endogenous pain inhibitory systems report unaltered activity of this descending inhibitory system. In contrast, studies analyzing brain structure and function in relation to (experimentally induced) pain provide preliminary evidence for altered central nociceptive processing in patients with chronic LBP. Finally, also psychosocial characteristics, such as inappropriate beliefs about pain, pain catastrophizing, and/or depression may contribute to the mechanisms of central sensitization. It tempting to speculate that ongoing nociception is associated with cortical and subcortical reorganization and may play an important role in the process of the chronification of LBP. Future prospective research should explore to what extent these changes are reversible and if this reversibility is associated with improved functioning of patients.