Discussion
The proposed study will describe the current management of shoulder pain in primary care and will help to determine which factors can predict patient recovery in PT practice. This study is designed to include key methodological features in order to minimize bias. These features include sampling of a representative cohort from physiotherapy setting with a high rate of follow-up.
Based on the sample of patients that will be recruited from physiotherapy practices, we aim to produce a pragmatic prediction model for PTs in primary care.
Possible prognostic factors and confounders are selected based on previous research.[4] The selected population of PTs in primary care enables us to include possible additional predictors such as characteristics from the PT and ultrasonographer. All medical consumption besides physiotherapy will be registered during follow-up questionnaires. Completeness of data collection will be stimulated by means of email reminders.
Although we will select a heterogeneous group of patients with shoulder complaints, we stress two important exclusion criteria. The first is that patients who had surgery of the shoulder in the previous 12 months are excluded, since these patients seem to differ in pathology and prognosis. Excluding these patients will ensure a more valid prediction model. Secondly, we postulate that PTs base their diagnosis and interventions on imaging techniques that were performed in the past; moreover, in case of the inter-rater reliability study, this could threaten blinding because most patients know the results of diagnostic imaging. Therefore, this study also excludes patients who had imaging of the shoulder in the 3 months prior to the start of physiotherapy treatment. PTs will be instructed to act as usual and are not instructed to adhere to a specific intervention protocol. This study aims to report on usual care in physiotherapy practice and provide insight into the diagnostic and therapeutic management of patients. Because patients are selected in primary care physiotherapy, we assume that they will represent the usual population consulting the PT with shoulder pain.
Patients in the control group will be randomly matched (by age and sex) to patients that receive an MSU by their PT. To avoid disease progression bias, their second MSU will be performed within 1 week; we do not expect that partial or full-thickness ruptures or calcifications will heal within 1 week. However, we cannot be certain that patient recovery is related to changes in patho-anatomical findings on MSU. Furthermore, the literature describes a high prevalence of rotator cuff tears in asymptomatic populations.[33,34] Therefore, we cannot ensure that these pathologies found on MSU images cause symptoms or constraints in daily activities for patients.
Radiologists and PTs will be blinded to each other's findings. Moreover, they will be blinded to clinical information that was not intended to form part of the MSU assessment. Radiologists are instructed to keep the patient blinded from MSU outcome. Blinding will be evaluated in the follow-up questionnaire of the patient.
From previous research it is known that MSU is operator dependent.[35] PTs and radiologists are instructed to use a standardized scanning protocol,[20] to ensure comparability in MSU procedures. Current management with MSU does not standardize pathology criteria. To assess the effect of current management of MSU in primary care we chose not to define criteria for pathology in this study. Nevertheless, we standardized possible outcome definitions for both the radiologist and PT in order to be able to categorize data.
We assume that inter-rater reliability between PT and radiologist might be influenced by the quality of ultrasound equipment and experience. Therefore, only equipment with transducer frequencies of at least 7.5 MHz will be used in physiotherapy practice and PTs should have at least 1 year of experience with ≥ 100 examinations of the shoulder.
Until now, reliability studies generally evaluated the inter-rater reliability between radiologists. However, PTs increasingly use MSU in daily practice and the reliability between different professions has not yet been evaluated.
It is hoped that this prospective cohort study will help improve the current management and prognosis of patients with shoulder pain.
Abbreviations
ShoCoDiP: Shoulder Complaints and Diagnostic Ultrasound In Physiotherapy; GP: General practitioner; PT: Physiotherapist; MSU: Musculoskeletal ultrasound imaging; MHz: Mega hertz; WAV-12: Dutch working alliance inventory; GPE: Global Perceived Effect; SDQ-NL: Dutch Shoulder Disability Questionnaire; SPADI: Shoulder Pain And Disability Questionnaire; SPS: Shoulder Pain Score; EQ-5D: Euroqol five-item quality of life questionnaire.
Authors' contributions
YK will collect the data together with MT and ED. YK will perform the analyses and wrote the manuscript together with WS and AV. YK and MT have full access to all the study data. WS is the principal investigator of the study and contributed to the design and coordination of the study and will contribute to the interpretation of the study results. MT collected part of the data, will perform part of the analyses and interpretation of the results. ED collected part of the data, will perform part of the analyses and interpretation of the results. RO is an expert in the field of musculoskeletal complaints and MSU, contributed to writing the manuscript and will contribute to the interpretation of the results. BK is an expert in the field of epidemiology and contributed to the design and will contribute to the interpretation of the results. AV is principal investigator and an expert in the field of epidemiology and contributed to the design and coordination of the study and will contribute to the interpretation of results. All other members from the ShoCoDiP study group GD, AB, MB, ET, JB and MH reviewed the manuscript, but did not meet the criteria for authorship. All authors read and approved the final manuscript.
Acknowledgements
There is no conflict of interest in our study. This study is funded by SIA-RAAK.
We would like to thank all contributions from radiologists and physiotherapists in our study. Laraine Visser, language editor for revising the manuscript.
Funding
This study is funded by SIA-RAAK. The ministry of education has made this funding available for the innovation and promotion of research.
BMC Musculoskelet Disord. 2013;14(62) © 2013 BioMed Central, Ltd.
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