Descriptive analysis of the musculoskeletal case load referred for ultrasound imaging in an Auckland imaging practice : a case study

Abstract

BACKGROUND: Musculoskeletal ultrasound (MSK US) imaging provides visualisation of a large number of superficial anatomical structures including nerves, joints, ligaments, tendons and muscles. The utility of ultrasound has been compared to other common imaging techniques such as Magnetic Resonance Imaging (MRI,) and is proving to be of similar, or better accuracy, for some applications. In New Zealand, ultrasound is a secondary level service, requiring referral from a primary practitioner. Included in primary health services are musculoskeletal practitioners (physiotherapists, osteopaths, podiatrists and chiropractors). These professions often rely on palpation and physical examination to inform diagnostic reasoning. However, there are limitations related to accuracy of this approach. Diagnostic ultrasound is a tool that can be used to inform clinical practice by aiding diagnosis of musculoskeletal conditions. To date, there appears to be just one study investigating referral protocols for musculoskeletal ultrasound.

AIM: The aim was to identify the descriptive characteristics of cases referred to one sonographer, working within a private MSK US practice located within an osteopathy tertiary teaching clinic in Auckland, New Zealand. Methods: A retrospective stratified random sample of 1000 cases was sampled from the total number of available records from one practice between 1 January 2016 and 31 December 2016. Two sources of information were available for each case: a single referral request (paper-based referral request), and the associated sonography imaging report (radiologist endorsed sonography report letter). Information extracted from these sources included patient demographic characteristics, referrer characteristics, descriptive referral request, and imaging report information. Systematized Nomenclature of Medicine – Clinical Terms coding was used to code referrer queries and sonographer’s diagnostic opinions.

RESULTS: The most common body regions referred for scanning were shoulder (27%) followed by knee (16%) and ankle (15%). Clinical indications for sonography requests were investigated, referrers wrote a maximum of 5 clinical indications per referral. Clinical indications generally included ‘location of pain’, ‘mechanism of injury’, ‘positive orthopaedic tests’, and ‘history of injury’. Only 27% of referrals provided a time since injury while the majority included other specific information such as clinical signs (e.g. ‘positive orthopaedic tests’). Overall, 35% of referrals did not include a query (median number of queries per referral was 1 (IQR=2)). Excluding those who did not include a clinical query with their request (35%), those who gave a smaller number of queries generally had a higher level of agreement between their queries and the sonographer’s opinion.

CONCLUSION: This project explored the characteristics of referral requests and sonography report. Further research is needed to explore the utility of referral for diagnostic ultrasound by musculoskeletal practitioners, and to determine whether referral protocols should be developed to increase efficacy of the referral process.