Thoracic computerised tomography scans in one hundred eighteen orthopaedic patients during the COVID-19 pandemic: identification of chest lesions; added values; help in managing patients; burden on the computerised tomography scan department

Abstract

Purpose: Based on the recent literature, chest computed tomography (CT) examination could aid for management of patients during COVID-19 pandemic. However, the role of chest CT in management of COVID-19 patients is not exactly the same for medical or surgical specialties. In orthopaedic or trauma emergency, abdomen, pelvis, cervical, dorsal, and lumbar spine CT are performed to investigate patients; the result is a thoracic CT scan incorporating usually the thorax; however, information about lung parenchyma can be obtained on this thorax CT, and manifestations of COVID-19 can be diagnosed. The objective of our study was to evaluate this role in orthopedic patients to familiarize orthopaedists with the value and limits of thoracic CT in orthopaedic surgery.

Materials and methods: Among the 1397 chest CT scans performed during the pandemic period from 1 March 2020 to 10 May 2020, in two centres with orthopaedic surgery, we selected all the 118 thoracic or chest CT performed for patients who presented to the Emergency Department of the hospital with a diagnosis of trauma for orthopaedic surgical treatment. Thirty-nine of these 118 patients were tested with PCR for the diagnosis of COVID-19 infection. Depending on clinical status (symptomatic or non-symptomatic), the information useful for the orthopaedist surgeon and obtained from the Chest CT scan according to the result of the PCR (gold standard) was graded from 0 (no or low value) to 3 (high value). The potential risks of chest CT as exposure to radiation, and specific pathway were analyzed and discussed. A group of patients treated during a previous similar period (1 March 2018 to 15 April 2018) was used as control for evaluation of the increase of CT scanning during the COVID-19 pandemic.

Results: Among the 118 patients with chest CT, there were 16 patients with positive COVID-19 chest CT findings, and 102 patients with negative chest CT scan. With PCR results as reference, the sensitivity, specificity, positive predictive value of chest CT in indicating COVID-19 infection were 81%, 93%, and 86%, respectively (p = 0.001). A useful information for the orthopaedic surgeon (graded as 1 for 71 cases, as 2 for 5 cases, and as 3 for 11 cases) was obtained from 118 chest CT scans for 87 (74%) patients, while the CT was no value in 30 (25%) cases, and negative value in one (1%) case. Roughly 20% of the total number of CT scanner performed over the pandemic period was dedicated to COVID-19, but only 2% were for orthopaedic or trauma patients. However, this was ten times higher than during the previous control period of comparison.

Conclusion: Although extremely valuable for surgery management, these results should not be overstated. The CT findings studied are not specific for COVID-19, and the positive predictive value of CT will be low unless disease prevalence is high, which was the case during this period.

Keywords: COVID-19; Chest CT scan; Coronavirus; Orthopaedic patients and COVID-19; PCR test; Pandemic COVID-19; Thoracic CT scan; Trauma patients and COVID-19.

Fig. 1

Flowchart of this study

Fig. 2

Typical findings of COVID-19 pneumonia: bilateral, sub-pleural ground-glass opacity (GGO), ill-defined margins, basal consolidation, and a slight right lower lobe predilection

Fig. 3

The confirmed (by ministry of health) number of COVID-19 patients was 4500 per million (0.45%) habitants for a population of 11.5 million in Belgium on the 10 May 2020

Fig. 4

Diagnosis of abnormalities compatible with COVID-19 on chest CT scans in different populations

Fig. 5

Diagnosis of confirmed COVID-19 with PCR in different populations

Fig. 6

Value of information in grade obtained from CT scan for management of orthopedic patients