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Diagnosing Occult Radiocarpal Fractures in Aotearoa: What is the Current Detection Rate, and Which Patients Are Accessing Early CBCT Imaging?

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Thesis(2.85 MB)

Date

2025

Authors

Supervisor

Hill, Julia
Saywell, Nicola

Item type

Thesis

Degree name

Master of Health Science

Journal Title

Journal ISSN

Volume Title

Publisher

Auckland University of Technology

Abstract

Introduction. Wrist injuries are common, and radiographic (X-ray) imaging remains the standard first-line diagnostic tool. However, its limited sensitivity for detecting carpal fractures can result in misdiagnosis, leading to delayed treatment, and prolonged recovery. Advancements in high-resolution imaging, including cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI), allow earlier and more accurate detection of occult fractures. In Aotearoa New Zealand, specialist referral is required for CBCT and MRI, often leading to long wait times and delays in diagnosis. On-site CBCT in acute care settings offers the potential to improve diagnostic speed and accuracy. Objective. Following the installation of an on-site CBCT scanner at a privately operated 24-hour clinic in a large urban area of New Zealand, a noticeable increase in radiocarpal fracture diagnoses was observed through the specialist fracture clinic service. This study evaluates radiocarpal fractures identified via CBCT in comparison with those detected through standard X-ray imaging, in patients presenting with acute wrist trauma. In addition, it explores patient demographics (including age, sex, ethnicity, and distance travelled to attend the clinic) and referral patterns for CBCT imaging. Methods. A retrospective observational review was conducted for patients with acute wrist trauma attending the specialist fracture clinic between 1 December 2023 and 30 May 2024, (n= 333). The clinic operates five days per fortnight and is staffed by a multidisciplinary team of emergency medicine specialists, radiographers, nurses and hand therapists. Ethical approval was granted by AUTEC (Ref 24/344). Data were extracted from patient electronic health and imaging records. Descriptive statistics and bivariate hypothesis testing were used to analyse imaging modality, fracture detection rates, and demographic characteristics. Results. A total of 325 wrist injuries were included in this study, with 186 fractures identified. Initial X-ray imaging detected approximately 75% of these fractures; however, one in four were occult. Cone beam computed tomography revealed a considerable number of fractures in patients whose wrist X-rays appeared normal, highlighting the limitations of traditional radiographic imaging in the assessment of radiocarpal fractures. X-ray imaging predominantly revealed fractures of the distal radius and scaphoid bones. Cone beam computed tomography however, detected a far broader spectrum of carpal injuries, particularly non-scaphoid fractures, with statistical analysis confirming significantly higher detection rates achieved with CBCT compared to X-ray. Paediatric fractures were predominantly diagnosed via X-ray, with 90% detected by this method, compared to 70% in adults. Despite similar overall fracture rates, adults were more frequently referred for CBCT (60% vs. 25%) and more likely to present with occult fractures. This disparity suggests potential underdiagnosis in paediatric cases and warrants caution when interpreting the true incidence of fractures in this population. No statistically significant differences in outcomes or imaging referral were observed by sex, ethnicity, or distance travelled to access the service. Due to small sample sizes, non-European ethnic groups were combined for analysis, though limited representation, particularly of Māori and Pasifika patients, reduced statistical power. No significant association was found between ethnicity and CBCT referral, but wide confidence intervals indicate uncertainty. Larger, more representative cohorts are needed to assess potential disparities. Conclusion. CBCT detects a wide range of carpal fractures, many of which are missed on standard X-ray imaging. Integrating CBCT into acute care settings enhances diagnostic accuracy, enabling more informed decisions about patient management.

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Keywords

wrist fracture, radiocarpal, distal radius, carpal, fracture, occult, adult, paediatric, cone beam computed tomography, CBCT, radiography, X-ray, Aotearoa, New Zealand

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Permanent link

http://hdl.handle.net/10292/20081

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Masters Theses