Prediction of poor outcomes six months following total knee arthroplasty in patients awaiting surgery

Background

Identification of patients experiencing poor outcomes following total knee arthroplasty (TKA) before the intervention could allow better case selection, patient preparation and, likely, improved outcomes. The objective was to develop a preliminary prediction rule (PR) to identify patients enrolled on surgical wait lists who are at the greatest risk of poor outcomes 6 months after TKA.

Methods

141 patients scheduled for TKA were recruited prospectively from the wait lists of 3 hospitals in Quebec City, Canada. Knee pain, stiffness and function were measured 6 months after TKA with the Western Ontario and McMaster Osteoarthritis Index (WOMAC) and participants in the lowest quintile for the WOMAC total score were considered to have a poor outcome. Several variables measured at enrolment on the wait lists (baseline) were considered potential predictors: demographic, socioeconomic, psychosocial, and clinical factors including pain, stiffness and functional status measured with the WOMAC. The prediction rule was built with recursive partitioning.

Results

The best prediction was provided by 5 items of the baseline WOMAC. The rule had a sensitivity of 82.1% (95% CI: 66.7-95.8), a specificity of 71.7% (95% CI: 62.8-79.8), a positive predictive value of 41.8% (95% CI: 29.7-55.0), a negative predictive value of 94.2% (95% CI: 87.1-97.5) and positive and negative likelihood ratios of 2.9 (95% CI: 1.8-4.7) and 0.3 (95% CI: 0.1-0.6) respectively.

Conclusions

The developed PR is a promising tool to identify patients at risk of worse outcomes 6 months after TKA as it could help improve the management of these patients. Further validation of this rule is however warranted before clinical use.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-299) contains supplementary material, which is available to authorized users.

Physiotherapy practice in the private sector: organizational characteristics and models

Background

Even if a large proportion of physiotherapists work in the private sector worldwide, very little is known of the organizations within which they practice. Such knowledge is important to help understand contexts of practice and how they influence the quality of services and patient outcomes. The purpose of this study was to: 1) describe characteristics of organizations where physiotherapists practice in the private sector, and 2) explore the existence of a taxonomy of organizational models.

Methods

This was a cross-sectional quantitative survey of 236 randomly-selected physiotherapists. Participants completed a purpose-designed questionnaire online or by telephone, covering organizational vision, resources, structures and practices. Organizational characteristics were analyzed descriptively, while organizational models were identified by multiple correspondence analyses.

Results

Most organizations were for-profit (93.2%), located in urban areas (91.5%), and within buildings containing multiple businesses/organizations (76.7%). The majority included multiple providers (89.8%) from diverse professions, mainly physiotherapy assistants (68.7%), massage therapists (67.3%) and osteopaths (50.2%). Four organizational models were identified: 1) solo practice, 2) middle-scale multiprovider, 3) large-scale multiprovider and 4) mixed.

Conclusions

The results of this study provide a detailed description of the organizations where physiotherapists practice, and highlight the importance of human resources in differentiating organizational models. Further research examining the influences of these organizational characteristics and models on outcomes such as physiotherapists’ professional practices and patient outcomes are needed.

Interprofessional practices of physiotherapists working with adults with low back pain in Québec's private sector: results of a qualitative study

BACKGROUND

Collaboration and interprofessional practices are highly valued in health systems, because they are thought to improve outcomes of care for persons with complex health problems, such as low back pain. Physiotherapists, like all health providers, are encouraged to take part in interprofessional practices. However, little is known about these practices, especially for private sector physiotherapists. This study aimed to: 1) explore how physiotherapists working in the private sector with adults with low back pain describe their interprofessional practices, 2) identify factors that influence their interprofessional practices, and 3) identify their perceived effects.

METHODS

Participants were 13 physiotherapists, 10 women/3 men, having between 3 and 21 years of professional experience. For this descriptive qualitative study, we used face-to-face semi-structured interviews and conducted content analysis encompassing data coding and thematic regrouping.

RESULTS

Physiotherapists described interprofessional practices heterogeneously, including numerous processes such as sharing information and referring. Factors that influenced physiotherapists' interprofessional practices were related to patients, providers, organizations, and wider systems (e.g. professional system). Physiotherapists mostly viewed positive effects of interprofessional practices, including elements such as gaining new knowledge as a provider and being valued in one's own role, as well as improvements in overall treatment and outcome.

CONCLUSIONS

This qualitative study offers new insights into the interprofessional practices of physiotherapists working with adults with low back pain, as perceived by the physiotherapists' themselves. Based on the results, the development of strategies aiming to increase interprofessionalism in the management of low back pain would most likely require taking into consideration factors associated with patients, providers, the organizations within which they work, and the wider systems.

A prospective cohort study to refine and validate the Panic Screening Score for identifying panic attacks associated with unexplained chest pain in the emergency department

INTRODUCTION

Panic-like anxiety (panic attacks with or without panic disorder), a highly treatable condition, is the most prevalent condition associated with unexplained chest pain in the emergency department. Panic-like anxiety may be responsible for a significant portion of the negative consequences of unexplained chest pain, such as functional limitations and chronicity. However, more than 92% of panic-like anxiety cases remain undiagnosed at the time of discharge from the emergency department. The 4-item Panic Screening Score (PSS) questionnaire was derived in order to increase the identification of panic-like anxiety in emergency department patients with unexplained chest pain.

METHODS AND ANALYSIS

The goals of this prospective cohort study were to (1) refine the PSS; (2) validate the revised version of the PSS; (3) measure the reliability of the revised version of the PSS and (4) assess the acceptability of the instrument among emergency physicians. Eligible and consenting patients will be administered the PSS in a large emergency department. Patients will be contacted by phone for administration of the criterion standard for panic attacks as well as by a standardised interview to collect information for other predictors of panic attacks. Multivariate analysis will be used to refine the PSS. The new version will be prospectively validated in an independent sample and inter-rater agreement will be assessed in 10% of cases. The screening instrument acceptability will be assessed with the Ottawa Acceptability of Decision Rules Instrument.

ETHICS AND DISSEMINATION

This study protocol has been reviewed and approved by the Alphonse-Desjardins research ethics committee. The results of the study will be presented in scientific conferences and published in peer-reviewed scientific journals. Further dissemination via workshops and a dedicated website is planned.

Obstacles to and facilitators of return to work after work-disabling back pain: the workers' perspective

INTRODUCTION

Back pain entails considerable costs, particularly because many injured workers are absent from work for long periods. Factors that influence return to work among workers with back pain are still, however, not well understood. This qualitative study aimed at documenting affected workers' perspective on the: 1--difficulties caused by back pain, and 2--most important obstacles to and facilitators of return to work.

METHODS

Two focus groups composed of workers having suffered from work-disabling back pain were held: a group of participants who had returned to work (n = 9) and a group of participants who had not returned or had recently returned to work (n = 10). The verbatim accounts of the discussions were transcribed and a content analysis was carried out that included a ranking of items.

RESULTS

Difficulties caused by back pain were related to: (1) personal, (2) family, (3) social, (4) occupational, and (5) financial factors, and (6) health services. Obstacles to and facilitators of return to work were of 4 different types: (1) occupational factors, (2) factors associated with the utilization of health services, (3) clinical, and (4) personal factors. Persistent pain, lack of access to information or support groups, and lack of collaboration and understanding from employer were the most important obstacles identified, whereas knowledge of one's limits and physical training were perceived to be the most important facilitators of return to work, ahead of work-related factors. Differences between groups' perceptions were attributed mainly to control beliefs.

CONCLUSIONS

Personal, clinical, occupational and health services factors are perceived by workers with back pain to play a crucial role in determining whether they return to work or not.

Determinants of pain, functional limitations and health-related quality of life six months after total knee arthroplasty: results from a prospective cohort study

Background

Total knee arthroplasty (TKA) is an effective procedure. However, for some patients, the outcomes are not satisfactory. Identification of TKA determinants could help manage these patients more efficiently. The purpose of this study was to identify pre- and perioperative determinants of pain, functional limitations and health-related quality of life (HRQoL) 6 months after TKA.

Methods

138 participants were recruited from 3 hospitals in Quebec City, Canada and followed up until 6 months after surgery. Data were collected through review of the subjects’ medical files and structured telephone interviews before and 6 months after TKA. Pain and functional limitations were measured with the Western Ontario and McMaster Osteoarthritis Index (WOMAC) and HRQoL was measured with the SF-36 Health Survey. Independent variables included demographic, socioeconomic, psychosocial, clinical and surgical characteristics of participants as well as data on health services utilization. Stepwise multiple regression analysis was used to assess the strength of the associations between the independent variables and the WOMAC and SF-36 scores.

Results

Higher preoperative pain, cruciate retaining implants and the number of complications were significantly associated with worse pain 6 months after TKA (p < 0.05) and explained 11% of the variance of the WOMAC pain score. Higher preoperative functional limitations, being single, separated, divorced or widowed, being unemployed or retired and the number of complications were significantly associated (p < 0.05) with worse functional limitations 6 months after TKA and explained 16% of the variance of the WOMAC function score. Lower preoperative HRQoL, contralateral knee pain, higher psychological distress and comorbidities were significantly associated (p < 0.05) with worse HRQoL 6 months after TKA and explained 23% of the variance of the SF-36 physical functioning score.

Conclusions

Several variables were found to be significantly associated with worse outcomes 6 months after TKA and may help identify patients at risk of poorer outcome. The identification of these determinants could help manage patients more efficiently and may help target patients who may benefit from extensive rehabilitation.

The impacts of pre-surgery wait for total knee replacement on pain, function and health-related quality of life six months after surgery

OBJECTIVE

The purpose of the current study was to assess, in patients scheduled for primary total knee replacement (TKR), the effects of pre-surgery waiting time on pain and functional limitations related to the knee joint undergoing surgery, on health-related quality of life (HRQoL) and on contralateral knee pain 6 months after surgery.

METHOD

A total of 141 patients scheduled for TKR were recruited from three hospitals in Quebec City, Canada, and followed up until 6 months after surgery. Pre-surgery wait, defined as the time between enrolment on the pre-surgery waiting list and surgery, was considered in four categories (≤3, >3-6, >6-9, >9 months). Pain and functional limitations were measured with the Western Ontario and McMaster Osteoarthritis Index (WOMAC). HRQoL was measured with the SF-36.

RESULTS

Mean pre-surgery waiting time was 184 (SD: 120.8) days. Six months after TKR, a significant difference was seen between the four groups of pre-surgery wait in terms of HRQoL SF-36 role physical [F(3, 136) = 2.74, P = 0.046] and contralateral knee WOMAC pain [F(3, 136) = 5.78, P = 0.0009] scores. Participants with the longest pre-surgery wait (>9 months) showed the worst scores 6 months after TKR.

CONCLUSIONS

Longer pre-surgery waiting time had a negative clinically important impact on HRQoL and contralateral knee pain 6 months after surgery.

A validity-driven approach to the understanding of the personal and societal burden of low back pain: development of a conceptual and measurement model

Introduction

While the importance and magnitude of the burden of low back pain upon the individual is well recognized, a systematic understanding of the impact of the condition on individuals is currently hampered by the lack of an organized understanding of what aspects of a person's life are affected and the lack of comprehensive measures for these effects. The aim of the present study was to develop a conceptual and measurement model of the overall burden of low back pain from the individual's perspective using a validity-driven approach.

Methods

To define the breadth of low back pain burden we conducted three concept-mapping workshops to generate an item pool. Two face-to-face workshops (Australia) were conducted with people with low back pain and clinicians and policy-makers, respectively. A third workshop (USA) was held with international multidisciplinary experts. Multidimensional scaling, cluster analysis, participant input and thematic analyses organized participants' ideas into clusters of ideas that then informed the conceptual model.

Results

One hundred and ninety-nine statements were generated. Considerable overlap was observed between groups, and four major clusters were observed - Psychosocial, Physical, Treatment and Employment - each with between two and six subclusters. Content analysis revealed that elements of the Psychosocial cluster were sufficiently distinct to be split into Psychological and Social, and a further cluster of elements termed Positive Effects also emerged. Finally, a hypothesized structure was proposed with six domains and 16 subdomains. New domains not previously considered in the back pain field emerged for psychometric verification: loss of independence, worry about the future, and negative or discriminatory actions by others.

Conclusions

Using a grounded approach, an explicit a priori and testable model of the overall burden of low back pain has been proposed that captures the full breadth of the burden experienced by patients and observed by experts.

Self-efficacy and health locus of control: relationship to occupational disability among workers with back pain

OBJECTIVES

Although self-efficacy and health locus of control (HLC) have been extensively studied in health research, little is known about their contribution to occupational disability among workers with back pain. This 2 year prospective study examined the association between these control belief constructs and "return to work in good health" (RWGH), a four-category, composite index of back pain outcome.

METHODS

The participants (n = 1,007, participation = 68.4%, follow-up = 86%) were workers with occupational disruptions who sought a medical consultation for non specific back pain in primary care and emergency settings in the Quebec City area, Canada. Information about self-efficacy for return to work (SERW) and HLC, as well as potential confounders, was collected during a telephone interview about 3 weeks after the baseline medical consultation. Polytomous logistic regression was used to assess the relationship between the baseline control variables and RWGH at 2 year. Odds ratios (OR) and their 95% confidence intervals were used to quantify the strength of associations. For all analyses, the "success" category was considered the reference group.

RESULTS

Although bivariate analyses showed a significant association between external HLC and RWGH at 2 year, this relationship was not significant in multivariate analyses. Higher scores on the self-efficacy questionnaire were however protective of "failure to return to work after attempt(s)" (OR: 0.28; 95% CI: 0.14-0.57) and of "failure to return to work" (OR: 0.19; 95% CI: 0.07-0.48) in multivariate analyses.

CONCLUSION

Self-efficacy is an important determinant of the occupational outcome of back pain.

Waiting for total knee replacement surgery: factors associated with pain, stiffness, function and quality of life

Background

Recent evidences show that education and rehabilitation while waiting for knee replacement have positive effects on the patients' health status. Identification of factors associated with worse pain, function and health-related quality of life (HRQoL) while waiting for surgery could help develop pre-surgery rehabilitation interventions that target specifically these factors and prioritize patients that may benefit the most from them. The objectives of this study were to measure pain, stiffness, function and HRQoL in patients at enrolment on waiting lists for knee replacement and to identify demographic, clinical, socioeconomic and psychosocial characteristics associated with these outcomes.

Methods

This study is part of a broader study measuring the effects of pre-surgery wait in patients scheduled for knee replacement. From 02/2006 to 09/2007, 197 patients newly scheduled for total knee replacement were recruited from the waiting lists of three university hospitals in Quebec City, Canada. Pain, stiffness and function were measured with the Western Ontario and McMaster Osteoarthritis Index (WOMAC) and HRQoL was measured with the SF-36 Health Survey. Stepwise multiple regression analysis was used to assess the strength of the associations between the independent variables and the WOMAC and SF-36 scores.

Results

The scores of all eight HRQoL physical and mental domains of the SF-36 were significantly lower than aged matched Canadian normative data (p < 0.05). Contralateral knee pain, higher psychological distress, higher body mass index (BMI) and the use of a walking aid were significantly associated with worse function (p < 0.05) and contributed to 22% of the variance of the WOMAC function score (multiple r = 0.47). A higher BMI, the use of a walking aid, contralateral knee pain and advanced age were significantly associated with worse physical function (p < 0.05) and contributed to 17% of the variance of the SF-36 HRQoL physical functioning score (multiple r = 0.41).

Conclusion

Patients waiting for knee replacement have poor function and HRQoL. Characteristics that were found to be associated with these outcomes could help develop pre-surgery rehabilitation program and prioritize patients that may benefit the most from them. Such programs could include interventions to reduce psychological distress, therapeutic exercises targeting both knees and weight loss management.

Interaction between postural risk factors and job strain on self-reported musculoskeletal symptoms among users of video display units: a three-year prospective study

OBJECTIVE

This study investigated a possible interaction between postural risk factors and job strain on the incidence proportion of self-reported musculoskeletal symptoms in the shoulder-neck, lower back and upper limbs regions.

METHODS

A cohort of white-collar workers (N=2431) was assessed with a self-administered questionnaire regarding postural risk factors and job strain at work. After a three-year follow-up, the six-month incidence proportion of musculoskeletal symptoms in the three body regions was measured with a modified version of the Nordic questionnaire. The analyses were stratified for gender. Interaction was defined as a departure from the addition of effects of individual risk factors, and its importance was estimated from the attributable proportion due to interaction and its 95% confidence interval (95% CI).

RESULTS

A significant attributable proportion of 0.80 (95% CI 0.23-1.37) due to interaction between postural risk factors and job strain was observed for men in the lower back region. An indication of interaction was found for women with attributable proportions due to interaction of 0.44 (95% CI -0.06-0.94), 0.27 (95% CI -0.34-0.88) and 0.36 (95% CI -0.33-1.05) for the shoulder-neck, lower back, and upper limbs regions, respectively.

CONCLUSIONS

The simultaneous presence of postural risk factors and job strain seems to increase the pathogenic effect of each exposure on the incidence proportion of musculoskeletal symptoms. This interaction effect is important for work intervention practices as success in decreasing any of these two risk factors could have the additional benefit of reducing up to 80% of new cases of musculoskeletal symptoms among participants exposed to both risk factors.

Agreement between a self-administered questionnaire on musculoskeletal disorders of the neck-shoulder region and a physical examination

Background

In epidemiological studies on neck-shoulder disorders, physical examination by health professionals, although more expensive, is usually considered a better method of data collection than self-administered questionnaires on symptoms. However, little is known on the comparison of these two methods of data collection. The agreement between self-administered questionnaires and the physical examination on the presence of neck-shoulders disorders was assessed in the present study.

Methods

This study was conducted among clerical workers using video display units. Prevalent cases were workers for whom neck-shoulder symptoms were present for at least 3 days during the previous 7 days and for whom pain intensity was greater than 50 mm on a 100 mm visual analogue scale. All 85 workers meeting this definition and a random sample of 102 workers who did not meet this definition were selected. Physical examination included measures of active range of motion and musculoskeletal strength. Cohen's kappa and global percent agreement were calculated to compare the two methods of data collection. The effect on the agreement of different question and physical examination definitions and the importance of the time interval elapsed between the administrations of the tests were also evaluated.

Results

Kappa coefficients ranged from 0.19 to 0.54 depending on the definitions used to ascertain disorders. The agreement was highest when the two instruments were administered 21 days apart or less (Kappa = 0.54, global agreement = 77%). It was not substantially improved by the addition of criteria related to functional limitations or when comparisons were made with alternative physical examination definitions. Pain intensity recorded during physical examination maneuvers was an important element of the agreement between questionnaire and physical examination findings.

Conclusion

These results suggest a fair to good agreement between the presence of musculoskeletal disorders ascertained by self-administered questionnaire and physical examination that may reflect differences in the constructs measured. Shorter time lags result in better agreement. Investigators should consider these results before choosing a method to measure the presence of musculoskeletal disorders in the neck-shoulder region.

Risk factors and prevention for spinal cord injury from diving in swimming pools and natural sites in Quebec, Canada: a 44-year study

BACKGROUND

Diving is the most frequent cause of spinal cord injury (SCI) from recreation and sport in Canada. This study was done to identify risk factors for SCI from diving in the province of Quebec.

METHODS

An interview survey was done for a target population of 203 subjects with a SCI from diving treated in the two specialized rehabilitation centers in Quebec during 1961-2004. Telephone interviews of consenting individuals were used to collect pertinent personal, equipment, and environmental factors for each incident.

RESULTS

Response was 44% (89/203); 92% were male and 85% <35 years old. Only 37% were aware prior to injury of the risk of SCI from diving, and only 33% had received water safety training. Swimming pools were the site of 51% (n=45) and natural bodies of water for 49% (n=44). 87% (n=39) of pools were single-unit home pools and 57% (n=26) above-ground. Depth indicators were absent for 100% of above-ground and 74% of in-ground pools. For SCI in in-ground pools, 63% resulted from striking the up-slope between deep and shallow ends. For dives at natural sites, a dock or wharf was the most frequent location, 36% (n=16). In 52% of pools and 79% of natural sites, depth was <1.4m (4.6ft). Signs prohibiting diving were absent in 96% of above-ground and 89% of in-ground pools. Alcohol was reported in 47% of SCIs.

INTERPRETATION

The target for prevention of diving SCI is male youths and young adults. Above-ground pools are too shallow and small for diving. Deep ends of many in-ground pools are excessively shallow and short since many SCIs resulted from striking the up-slope. Prevention of SCI from diving needs to focus on education of potential victims, pool vendors and manufacturers, and regulations for safety norms in private pools. Water safety should highlight diving as a high-risk activity, and emphasize that most home pools and natural sites are unsafe. Safer evidence-based pool designs and more effective warnings need to be implemented.

A consensus approach toward the standardization of back pain definitions for use in prevalence studies

STUDY DESIGN

A modified Delphi study conducted with 28 experts in back pain research from 12 countries.

OBJECTIVE

To identify standardized definitions of low back pain that could be consistently used by investigators in prevalence studies to provide comparable data.

SUMMARY OF BACKGROUND DATA

Differences in the definition of back pain prevalence in population studies lead to heterogeneity in study findings, and limitations or impossibilities in comparing or summarizing prevalence figures from different studies.

METHODS

Back pain definitions were identified from 51 articles reporting population-based prevalence studies, and dissected into 77 items documenting 7 elements. These items were submitted to a panel of experts for rating and reduction, in 3 rounds (participation: 76%). Preliminary results were presented and discussed during the Amsterdam Forum VIII for Primary Care Research on Low Back Pain, compared with scientific evidence and confirmed and fine-tuned by the panel in a fourth round and the preparation of the current article.

RESULTS

Two definitions were agreed on a minimal definition (with 1 question covering site of low back pain, symptoms observed, and time frame of the measure, and a second question on severity of low back pain) and an optimal definition that is made from the minimal definition and add-ons (covering frequency and duration of symptoms, an additional measure of severity, sciatica, and exclusions) that can be adapted to different needs.

CONCLUSION

These definitions provide standards that may improve future comparisons of low back pain prevalence figures by person, place and time characteristics, and offer opportunities for statistical summaries.

Predicting Discharge of Trauma Survivors to Rehabilitation

OBJECTIVES

To conduct a population-based survey among trauma survivors on accessibility to rehabilitation services in metropolitan, urban, and rural areas in Quebec (Canada), we attempted to use trauma registries as a sampling frame of subjects discharged to rehabilitation. Discharge destinations were inaccurate in many registries, preventing straightforward identification of the survey subjects. Using the best registry data, we aimed to identify predictors of rehabilitation discharge and to use them to specify a reliable sampling frame for the survey.

DESIGN

A logistic predictive model of rehabilitation discharge was developed. This model was applied to data from metropolitan, urban, and rural trauma centers to identify all subjects predicted to be discharged to a rehabilitation facility.

RESULTS

Age, acute-care length of stay, injury-severity score, lower-limb injuries, and seven other predictors were included in the model that generated an area under the ROC curve (AUC) of 0.83 and a classification accuracy of 76.6%. The metropolitan, urban, and rural frames were slightly different. They included, respectively, 808, 798, and 929 subjects.

CONCLUSIONS

The procedure helped us bypass largely inaccurate data from trauma registries. The sampling frames reflected severely injured trauma survivors who were likely to have been referred to postacute rehabilitation.

Does patient-physiotherapist agreement influence the outcome of low back pain? A prospective cohort study

Background

Recent research suggests that agreement between patients' and health professionals' perceptions may influence the outcome of various painful conditions. This issue has received little attention in the context of low back pain and physiotherapy interventions. The current study aimed at exploring the relationship between patient-physiotherapist agreement on baseline low back pain intensity and related functional limitations, and changes in patient outcomes four weeks later.

Methods

Seventy-eight patient-physiotherapist dyads were included in the study. At baseline, patients and physiotherapists completed a Numerical Rating Scale and the Roland-Morris Disability Questionnaire. Patients' perceptions were reassessed over the phone at follow-up.

Results

Using multiple regression, baseline level of patient-physiotherapist agreement on pain intensity was associated with both outcome measures at follow-up. Agreement on functional limitations had no impact on outcomes.

Conclusion

The results of this study indicate that patient-physiotherapist agreement has some impacts on the short-term outcomes of low back pain. Further research is needed to confirm these findings.

Determinants of "return to work in good health" among workers with back pain who consult in primary care settings: a 2-year prospective study

Many factors have been linked to return to work after a back pain episode, but our understanding of this phenomenon is limited and cross-sectional dichotomous indices of return to work are not valid measures of this construct. To describe the course of "return to work in good health" (RWGH--a composite index of back pain outcome) among workers who consulted in primary care settings for back pain and identify its determinants, a 2-year prospective study was conducted. Subjects (n = 1,007, 68.4%) were workers who consulted in primary care settings of the Quebec City area for a nonspecific back pain. They completed five telephone interviews over 2 years (follow-up = 86%). Analyses linking baseline variables with 2-year outcome were conducted with polytomous logistic regression. The proportion of "success" in RWGH increased from 18% at 6 weeks to 57% at 2 years. In women, persistent pain, pain radiating to extremities, increasing job seniority, not having a unionized job, feeling that the physician did listen carefully and increasing fear-avoidance beliefs towards work and activity were determinants of "failure" in RWGH. In men, decreasing age, cigarette smoking, poor self-reported health status, pain in the thoracic area, previous back surgeries, a non-compensated injury, high pain levels, belief that job is below qualifications, likelihood of losing job, job status, satisfaction with health services and fear-avoidance beliefs towards work were all significant. RWGH among workers with back pain receives multiple influences, especially among men. In both genders, however, fear-avoidance beliefs about work are associated with failure and high self-efficacy is associated with success.

Does back pain prevalence really decrease with increasing age? A systematic review

BACKGROUND

It is believed that the prevalence of back pain decreases around the middle of the sixth decade. However, back pain is still among the most commonly reported symptoms in the elderly and osteoarthritis, disc degeneration, osteoporosis and spinal stenosis all increase with age. In light of this, it is difficult to understand why the prevalence of back pain would decrease with increasing age.

OBJECTIVE

This study aimed at summarising the scientific evidence on the trends of back pain prevalence with age.

METHODS

Population-based studies reporting the prevalence of back pain, including people aged 65 years and over, were systematically retrieved from several bibliographic databases. These were read and assessed by two reviewers, and papers retained ('good quality studies') were aggregated according to specific criteria.

RESULTS

Good quality studies showed a large heterogeneity as to their methods and prevalence figures. No specific patterns were detected by country nor outcome measure. However, most studies that considered severe forms of back pain found an increase of prevalence with increasing age. The curvilinear association between age and back pain prevalence that is widely mentioned in the literature was found only for benign and mixed problems.

CONCLUSIONS

The evidence concerning the association of back pain prevalence with age is more sparse than currently believed and this association seems to be modified by the severity of the problem. This knowledge could have important public health implications, as the proportion of older people will increase considerably in the coming years in most industrialised societies.

Patient-physiotherapist agreement in low back pain

Agreement between patients' and health professionals' perceptions has been shown to be low to moderate for different aspects of the patients' pain experience. Little is known, however, about patient-physiotherapist agreement in low back pain. The study objectives were to describe patient-physiotherapist agreement for low back pain intensity and functional limitations, and to identify correlates of agreement. A cross-sectional design was used. Seventy-eight patients with acute/subacute nonspecific low back pain and their respective physiotherapists were included in the study. After the initial physiotherapy consultation, patients and physiotherapists completed a Numerical Rating Scale and the Roland-Morris Disability Questionnaire. Intraclass correlation coefficients (ICC) were used to measure chance-corrected agreement. Patients' and physiotherapists' mean ratings were also compared using paired t tests. Multiple regression analyses were conducted to identify factors associated with agreement measures. The level of agreement was moderate for pain intensity (ICC = 0.55, 95% confidence interval [CI]: 0.38-0.69) and functional limitations (ICC = 0.56, 95% CI: 0.22-0.74). Both variables were rated significantly (P < .05) lower by the physiotherapists than by the patients. Higher ratings by the patients for pain and functional limitations were related to higher differences in perceptions between patients and physiotherapists. This report shows that physiotherapists' perceptions of their patients' pain intensity and functional limitations often differ from their patients'.

PERSPECTIVE

The findings of this study indicate that there are frequent discrepancies between patients' and physiotherapists' perceptions of the patients' low back pain experience. Gaining a better understanding of the level of patient-physiotherapist agreement and identifying the correlates of agreement may help improve physiotherapists' interventions with people with low back pain.

Prevalence of musculoskeletal activity limitation and associated factors among adults in the general population in the 1998 Quebec Health Survey

OBJECTIVE

To estimate the prevalence of short term and longterm musculoskeletal activity limitation among the general adult population of the province of Quebec, and to identify which factors are associated with these limitations.

METHODS

We analyzed cross-sectional data from the 1998 Quebec Health Survey. Logarithmic binomial regression models were used to estimate prevalence ratios of (1) short term activity limitation related to musculoskeletal disorders (MSD); and (2) longterm activity limitation related to MSD in relation to demographic and behavioral variables and comorbidity factors.

RESULTS

About one-fifth of participants reporting short term activity limitation and one-third of participants reporting longterm activity limitation mentioned MSD as a cause. Multivariate analyses showed that higher age, lower income, being overweight, ill defined nervousness, and the number of traumatic events that occurred before age 18 years were significantly associated with short term and longterm activity limitation related to MSD, whereas being in the minority ethnic group was protective for both outcomes. Female sex, physical inactivity, being a former alcohol drinker, and mental disorders were also associated with longterm activity limitation.

CONCLUSION

MSD are a major cause of activity limitation among adults from Quebec. With the aging population and the increasing prevalence of obesity, increasing prevalence of activity limitation related to MSD is to be expected.

Psychological distress confirmed as predictor of long-term back-related functional limitations in primary care settings

BACKGROUND AND OBJECTIVE

Among the possible predictors of back pain outcomes that have been studied, indices of psychological distress have been found to have a high prognostic value. This study aimed at assessing the validity of a predictive model of long-term back-related functional limitations that is based on psychological distress, in a new sample of subjects.

STUDY DESIGN AND SETTING

The study was conducted with 860 French-speaking workers who consulted for nonspecific back pain in primary care settings of the Quebec City area. They were interviewed at baseline and again 2 years later. Psychological distress and back-related functional limitations were measured respectively with items drawn from the Symptom Checklist 90 Revised and the Roland-Morris Disability Questionnaire. Analyses were conducted by forcing the model previously developed on a sample of English-speaking health maintenance organization (HMO) members of Washington state.

RESULTS

The model correctly classified 82% of subjects as to their functional limitation status at 2 years. The accuracy of the prediction was similar to that reported in the original study.

CONCLUSION

The fact that this predictive model of back-related functional limitations led to similar results in a different sample of subjects and in another language brings strong support to its validity.

A clinical return-to-work rule for patients with back pain

BACKGROUND

Tools for early identification of workers with back pain who are at high risk of adverse occupational outcome would help concentrate clinical attention on the patients who need it most, while helping reduce unnecessary interventions (and costs) among the others. This study was conducted to develop and validate clinical rules to predict the 2-year work disability status of people consulting for nonspecific back pain in primary care settings.

METHODS

This was a 2-year prospective cohort study conducted in 7 primary care settings in the Quebec City area. The study enrolled 1007 workers (participation, 68.4% of potential participants expected to be eligible) aged 18-64 years who consulted for nonspecific back pain associated with at least 1 day's absence from work. The majority (86%) completed 5 telephone interviews documenting a large array of variables. Clinical information was abstracted from the medical files. The outcome measure was "return to work in good health" at 2 years, a variable that combined patients' occupational status, functional limitations and recurrences of work absence. Predictive models of 2-year outcome were developed with a recursive partitioning approach on a 40% random sample of our study subjects, then validated on the rest.

RESULTS

The best predictive model included 7 baseline variables (patient's recovery expectations, radiating pain, previous back surgery, pain intensity, frequent change of position because of back pain, irritability and bad temper, and difficulty sleeping) and was particularly efficient at identifying patients with no adverse occupational outcome (negative predictive value 78%- 94%).

INTERPRETATION

A clinical prediction rule accurately identified a large proportion of workers with back pain consulting in a primary care setting who were at a low risk of an adverse occupational outcome.

Prevalence of musculoskeletal pain and associated factors in the Quebec working population

BACKGROUND

While the determinants of musculoskeletal pain are numerous, few studies conducted among workers have taken into account, altogether, physical factors, psychosocial factors (personal and work-related) and individual characteristics.

OBJECTIVES

To estimate the 1-year prevalence of musculoskeletal pain in the Quebec working population by gender and anatomical site, and to determine which factors are associated with these prevalence figures.

METHODS

Data came from the 1998 Quebec Health Survey and included 9,496 individuals. One-year period prevalences for neck pain, back pain and pain in the upper and lower extremities were calculated for men and women. Logistic regression analyses were conducted to estimate the associations between individual, physical and psychosocial work factors, on one hand, and musculoskeletal pain in the four body regions, on the other hand.

RESULTS

For both genders back pain was the most frequent musculoskeletal symptom that had disturbed their activities during the past year. The largest difference between genders was observed for neck pain (women: 18%; men: 11%). Multivariate analyses indicated that physical and psychosocial work factors, as well as psychological variables, were associated with musculoskeletal pain in different body regions. Body mass index was associated only with pain in lower extremities for both genders.

CONCLUSIONS

The results of this study suggest that interventions aimed at reducing musculoskeletal pain should take into account personal and work-related psychosocial variables, in addition to physical workload.

Back-related functional limitations among full-time homemakers: a comparison with women employed full-time outside the home

STUDY DESIGN

Two-year prospective study with repeated measurements.

OBJECTIVES

To describe back-related functional limitations and their evolution among full-time female homemakers and to compare them to that of women employed full-time outside the home.

SUMMARY OF BACKGROUND DATA

Back pain is not limited to the formal "working" population. However, there is little information on the consequences of back pain in "nonworking" individuals.

METHODS

Subjects were members of a large Health Maintenance Organization who consulted a physician for nonspecific back pain. Telephone interviews were conducted 4 to 6 weeks after the consultation and 1 and 2 years later. Back-related functional limitations were measured with a modified 16-item Roland-Morris scale. Analyses were conducted on 104 full-time homemakers and 288 women employed full-time outside the home.

RESULTS

The mean Roland-Morris score among homemakers was 34.4% at baseline and dropped to 22.8% at 2 years. In multiple regression analyses, 2-year back-related functional limitations were significantly associated with symptoms of depression, pain intensity, and the number of days with back pain in the past 6 months measured at baseline, but not with employment status. Functional limitations were not different between homemakers and women employed outside the home, even after adjustment for confounders.

CONCLUSIONS

In this study, the functional consequences of back pain had a similar nature and 2-year evolution among full-time homemakers and women employed full-time outside the home. These results did not demonstrate an effect of formal employment on the functional consequences of back pain among women.

Psychosocial job factors and the one-year evolution of back-related functional limitations

OBJECTIVES

This 1-year prospective study aimed at assessing the association between some psychosocial job characteristics and back-related functional limitations.

METHODS

The participants were 849 workers who sought medical consultation for nonspecific back pain in primary care settings of the Quebec City area. Information on job decision latitude, psychological demands, and social support at work was collected during a telephone interview conducted after the medical consultation. Back-related functional limitations were measured at baseline and 1 year later with the Roland-Morris Disability Questionnaire. The analyses were stratified by gender. Social support at work and the type of back pain were considered potential effect modifiers. Several potential confounders were also considered in the multiple regression analyses that were conducted to isolate the effect of the job psychological demands and decision latitude on the 1-year level of back-related functional limitations.

RESULTS

A modest difference in the 1-year Roland-Morris average scores was found only among the women and only for the association between job decision latitude with back-related functional limitations, according to the level of social support at work. This difference was of limited clinical significance. Analyses by type of back pain showed, however, a clinically significant association between the combination of high psychological demands and low decision latitude and back-related functional limitations only for subjects with persistent pain.

CONCLUSIONS

Job psychological demands and decision latitude have little influence on the 1-year evolution of back-related functional limitations for one-time and recurrent back-pain problems. However, our results suggest that this association could be important for workers with persistent pain.

Impact of transfer delays to rehabilitation in patients with severe trauma

OBJECTIVE

To measure the effect on rehabilitation outcomes of administrative delays in transferring patients from a level I trauma center to inpatient rehabilitation.

DESIGN

Retrospective cohort study.

SETTINGS

Level I trauma center and an inpatient rehabilitation center in Quebec, Canada.

PARTICIPANTS

A total of 289 patients with severe trauma admitted to inpatient rehabilitation from a level I trauma center between 1994 and 1999.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Length of stay (LOS) in rehabilitation, motor and cognitive function at discharge from rehabilitation, interruptions in rehabilitation, and disposition at discharge.

RESULTS

Shorter administrative delays were associated with shorter rehabilitation LOS (P<.01) improved cognitive function (P=.02) and had a negative but statistically nonsignificant association with motor function at discharge. No effect was observed for rehabilitation interruptions or dispositions at discharge.

CONCLUSIONS

Transferring trauma patients more quickly to inpatient rehabilitation can affect rehabilitation outcomes positively. It can also lead to an economy of resource use in both acute and rehabilitation settings.

Scapular behavior in shoulder impingement syndrome

OBJECTIVE

To quantify the contribution of each scapular rotation to the scapular total range of motion (ROM) in both shoulders of persons with a unilateral shoulder impingement syndrome (SIS), to compare 3-dimensional (3D) scapular attitudes of their symptomatic and asymptomatic shoulders in flexion and in abduction, and to characterize the scapular behavior of these subjects by classifying them into subgroups based on scapular tilting differences between their symptomatic and asymptomatic shoulders.

DESIGN

Comparisons of 3D scapular attitudes, scapular total ROM, and percentage of contributions of each scapular rotation to the scapular total ROM.

SETTING

A motricity laboratory.

PARTICIPANTS

Fifty-one subjects, including 41 with a SIS (29 had an asymptomatic contralateral shoulder) and 10 healthy subjects.

INTERVENTIONS

The 3D scapular attitudes were calculated with the subjects in a standardized seated position; with the arm at rest; or at 70 degrees, 90 degrees, and 110 degrees of shoulder flexion and abduction. Axial rotation angles were calculated using a fixed set of Cardanic angles.

MAIN OUTCOME MEASURES

At 90 degrees of arm elevation, data from 10 shoulders of healthy subjects were used to set up normative values (99% confidence interval of mean 3D scapular attitudes) to compare with 3D scapular attitudes of symptomatic and asymptomatic shoulders of SIS subjects. We analyzed the scapula behavior of subjects with SIS and classified them into subgroups based on scapular anterior tilting asymmetry.

RESULTS

In flexion, almost half of the scapular total ROM was provided by anterior tilting (48.2%-51.3%), whereas in abduction, external rotation (40.3%-42.4%) was the main contributor. Scapular total ROM was higher in abduction than in flexion in all arm positions for both shoulder groups (P <.01). Also, 3D scapular attitude patterns of both shoulders of SIS subjects were different from those of healthy subjects. At 90 degrees, scapular asymmetry in anterior tilting allowed us to classify SIS subjects with respect to more (lead) or less (lag) scapular tilting in the affected side (P <.0001) or no difference (P =.11) between the sides (symmetrical). No significant differences (P >.05), except for a small 2 degrees difference in transverse rotation during arm flexion at 110 degrees (P =.002), were observed in 3D scapular attitudes and scapular total ROM between both shoulders of SIS subjects. Patterns of 3D scapular attitudes and scapular total ROM were significantly different between flexion and abduction arm positions (P <.05).

CONCLUSIONS

The contribution of rotations and scapular total ROM differed according to the plane of arm elevation in SIS subjects. Group analyses revealed no differences in 3D scapular attitudes between symptomatic and asymptomatic shoulders of subjects with unilateral SIS. This could be caused by the use, in SIS subjects, of inappropriate neuromuscular strategies affecting both shoulders. However, individual analyses revealed scapular asymmetry in the sagittal plane, which suggests that SIS subjects with less anterior tilting in the symptomatic shoulder, as compared with the asymptomatic contralateral one, may be at high risk of developing chronic SIS. This last finding provides scientific evidence to focus rehabilitation protocols toward a restoration of anterior tilting.

Formal education and back pain: a review

OBJECTIVES

To summarise the scientific evidence on the relation between educational status and measures of the frequency and the consequences of back pain and of the outcomes of interventions among back pain patients, and to outline possible mechanisms that could explain such an association if found.

DESIGN

Sixty four articles published between 1966 and 2000 that documented the association of formal education with back pain were reviewed.

MAIN RESULTS

Overall, the current available evidence points indirectly to a stronger association of low education with longer duration and/or higher recurrence of back pain than to an association with onset. The many reports of an association of low education with adverse consequences of back pain also suggest that the course of a back pain episode is less favourable among persons with low educational attainment. Mechanisms that could explain these associations include variations in behavioural and environmental risk factors by educational status, differences in occupational factors, compromised "health stock" among people with low education, differences in access to and utilisation of health services, and adaptation to stress. Although lower education was not associated with the outcomes of interventions in major studies, it is difficult, in light of the current limited available evidence, to draw firm conclusions on this association.

CONCLUSION

Scientific evidence supports the hypothesis that less well educated people are more likely to be affected by disabling back pain. Further study of this association may help advance our understanding of back pain as well as understanding of the relation between socioeconomic status and disease as a general phenomenon.

A comparison of pain, functional limitations, and work status indices as outcome measures in back pain research

STUDY DESIGN

We conducted a prospective study with a 2-year follow-up.

OBJECTIVE

To compare pain, functional limitations, and work status indices as measures of outcome among back pain patients.

SUMMARY OF BACKGROUND DATA

Work status, pain, and functional limitations indices are often considered as interchangeable outcome measures in back pain research. This perspective has been criticized by several authors, who argue that each of these outcome measures reflects a different construct that may vary independently of the others.

METHODS

The study was conducted on 720 patients, who sought care for back pain in primary care settings of a large health maintenance organization in 1989-90, and were interviewed one month and two years later. X2 analyses and receiver operating characteristic curves were used to compare the accuracy of a pain rating and a modified 16-item Roland-Morris score in classifying patients on work status and on the change in work status over time.

RESULTS

Moderate agreement between the pain and functional limitations measures and work status was observed. Pain and functional limitations change scores agreed moderately with improvement in work status, but were poorly associated with decline in work status.

CONCLUSIONS

Although the pain, functional limitations, and work status indices examined in this study are related, they are not equivalent and should not be regarded as interchangeable. These results argue for a clearer distinction of outcome measures in back pain research.

Predicting long-term functional limitations among back pain patients in primary care settings

To identify predictors of back-related long-term functional limitations, 1213 adult enrollees of a Health Maintenance Organization (HMO) in Washington state were interviewed about a month after a consultation for back pain in a primary care setting in 1989-1990, and followed each year thereafter. Out of 100 factors documented at the one-month assessment, measures of somatization, depression, functional limitations, and pain were the strongest predictors of two-year modified Roland-Morris score among a random subsample of 569 subjects. A multiple regression model containing the Symptom Checklist Depression and Somatization scores, the one-month modified Roland-Morris score and the number of pain days in the past six months explained about 30% of the variance in the outcome. Using recursive partitioning, a very simple model was developed to identify patients at high risk of sustaining long-term significant functional limitations. The regression model and the recursive partitioning model were successfully tested in a fresh sample of patients (n = 644). Clinical application of the recursive partitioning model and methodological aspects of this study are discussed.

Seasonal variation of twin births in Washington State

Twin births are known to vary across seasons in several countries. It has been hypothesized that this variation may be due to seasonal changes in luminosity leading to pineal gland-mediated multiovulation among susceptible mothers. To describe seasonal variation of twin births in Washington State, all mothers residing in Washington State who gave birth to both a pair of twins and a singleton baby between 1984-1990 (n = 1168) were identified through linkage of computerized State birth certificates. Using a "matched-on-mother" case-control design, the estimated month of conception of twin gestations (the "case" events) were compared to that for their singleton siblings (the "control" events) to determine their relative occurrence during periods of high vs low sunlight in accordance with local climatological data. For the study population as a whole, there was only a slight tendency for twins to have been conceived during the period of high sunlight compared to their singleton siblings (OR = 1.3, 95% C.I. = 1.0-1.7). When stratified by concordant-sex vs discordant-sex, however, more discordant-sex twin pairs were conceived during the light period than corresponding singletons (OR = 1.7, 95% C.I. = 1.0-2.8), whereas no association was found for concordant-sex twins (OR = 1.1, 95% C.I. = 0.8-1.6). The presence of an association only among discordant-sex twins, all of whom are dizygotic, is consistent with the hypothesis that exposure to sunlight may stimulate multiple ovulation, and thus increase the incidence of twin gestations among twin-prone mothers.