Diagnostic accuracy of the Ottawa ankle rule to exclude fractures in acute ankle injuries in adults: a systematic review and meta-analysis.

BACKGROUND: Ankle traumas are common presenting injuries to emergency departments in Australia and worldwide. The Ottawa Ankle Rules (OAR) are a clinical decision tool to exclude ankle fractures, thereby precluding the need for radiographic imaging in patients with acute ankle injury. Previous studies support the OAR as an accurate means of excluding ankle and midfoot fractures, but have included a paediatric population, report both the ankle and mid-foot, or are greater than 5 years old. This systematic review and meta-analysis aimed to update and assess the existing evidence of the diagnostic accuracy of the Ottawa Ankle Rule (OAR) acute ankle injuries in adults. METHODS: A systematic search and screen of was performed for relevant articles dated 1992 to 2020. Prospective and retrospective studies documenting OAR outcomes by physicians to assess ankle injuries were included. Critical appraisal of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Outcomes related to psychometric data were pooled using random effects or fixed effects modelling to calculate diagnostic performance of the OAR. Between-study heterogeneity was assessed using the Higgins I2 test, with Spearman's correlation test for threshold effect. RESULTS: From 254 unique studies identified in the screening process, 15 were included, involving 8560 patients from 13 countries. Sensitivity, specificity, negative likelihood ratio, positive likelihood ratio and diagnostic odds ratio were 0.91 (95% CI, 0.89 to 0.92), 0.25 (95% CI, 0.24 to 0.26), 1.47 (95% CI, 1.11 to 1.93), 0.15 (95% CI, 0.72 to 0.29) and 10.95 (95% CI, 5.14 to 23.35) respectively, with high between-study heterogeneity observed (sensitivity: I2 = 94.3%, p < 0.01; specificity: I2 = 99.2%, p < 0.01). Most studies presented with low risk of bias and concern regarding applicability following assessment against QUADAS-2 criteria. CONCLUSIONS: Application of the OAR is highly sensitive and can correctly predict the likelihood of ankle fractures when present, however, lower specificity rates increase the likelihood of false positives. Overall, the use of the OAR tool is supported as a cost-effective method of reducing unnecessary radiographic referral, that should improve efficiency, lower medical costs and reduce waiting times.

Establishing diagnostic reference levels for pediatric fluoroscopic examinations in a tertiary hospital.

BACKGROUND: Diagnostic reference levels (DRLs) identify unusually high patient radiation exposures and are required for dose optimisation. DRLs for pediatric fluoroscopic examinations are not widely determined in Australia. OBJECTIVE: Our objectives were to establish DRLs for pediatric fluoroscopic examinations in a South Australian tertiary hospital and compare these to previously published data and to explore relationships between patient dose area product (DAP), age and fluoroscopy times. MATERIALS AND METHODS: Dose data from 365 pediatric patients undergoing 5 fluoroscopic examinations were retrospectively collected for a 3-year period commencing January 2018 to develop local DRLs. Relationships between DAP, age and fluoroscopy time were explored using scatterplots, Spearman's correlation, and regression analyses. RESULTS: Local DRLs were significantly lower than data published previously, possibly reflecting technological and procedural advancements. Each 1-year increase in patient age was associated with a 0.77 µGy·m2 increase in DAP for barium meal and follow-through studies (95% confidence interval [CI]=0.055, 1.48) (P=0.04), and a 1.37 µGy·m2 increase in DAP for barium swallow studies (95% CI=0.61, 2.12) (P<0.001). A low correlation was demonstrated between DAP and fluoroscopy time for micturating cystourethrography studies (r=0.35, 95% CI=0.15, 0.51, P<0.001) and barium meal and follow-through studies (r=0.37, 95% CI= -0.011, 0.65, P=0.05). Age and fluoroscopy time were not significantly related. CONCLUSION: This study provides updated Australian pediatric fluoroscopic DRLs, with the intention of promoting a national database for benchmarking pediatric doses. The local DRLs can be used for dose comparisons and optimisation between facilities.

Adequacy of clinical information in X-ray referrals for traumatic ankle injury with reference to the Ottawa Ankle Rules-a retrospective clinical audit.

STUDY OBJECTIVE: To assess the adequacy of clinical information with reference to the Ottawa Ankle Rules (OAR) in X-ray referrals for adults with traumatic ankle injury in the ED of a South Australian tertiary hospital and report upon referring trends between emergency department clinicians. METHODS: A retrospective clinical audit of adult ankle X-ray referrals in the emergency department was conducted. Eligible referrals were screened for their adherence to the OAR, patient details, clinical history and referrer. A logistic regression was used to determine the influence of these factors on the likelihood of being referred for X-rays despite not meeting the OAR criteria. Sensitivity, specificity, positive and negative likelihood ratios and their associated confidence intervals were calculated to assess the diagnostic accuracy of the OAR for those referred. RESULTS: Out of the 262 eligible referrals, 163 were deemed to have met the criteria for the OAR. Physiotherapists showed the highest OAR compliance of 77.3% and were the most accurate in their use of the rules, with a sensitivity of 0.86. Medical officers, registrars and interns were 2.5 times more likely to still refer a patient for X-ray if they did not meet the OAR criteria, compared to physiotherapists as the baseline. Patient age, duration of injury etc. were not significantly associated with likelihood of referral (even when they did not meet OAR criteria). The overall sensitivity, specificity, positive and negative likelihood ratios of the OAR were 0.59 (95% CI [0.47-0.71]), 0.37 (95% CI [0.30-0.44]), 0.93 (95% CI [0.76-1.16]) and 1.10 (95% CI [0.82-1.48]) respectively. CONCLUSION: The results of this audit demonstrated poor sensitivity and moderate compliance by referrers with the rule. Reasonable evidence exists for the implementation of individual and/or institutional-based change strategies to improve clinician compliance and accuracy with use of the OAR.