Usefulness of computed tomography based three-dimensional reconstructions to assess the critical shoulder angle.

BACKGROUND: The critical shoulder angle (CSA) is a radiographic measurement that provides an assessment of both glenoid inclination and acromial length. Higher values may correlate with the presence of rotator cuff tears. However, it is difficult to obtain a high-quality true anteroposterior (AP) radiograph of the shoulder, with any excess scapular version or flexion/extension resulting in deviation from the true CSA value. Three-dimensional (3D) bony reconstructions of computed tomography (CT) shoulder scans may be able to be rotated to obtain a similar view to that of true AP radiographs. AIM: To compare CSA measurements performed on 3D bony CT reconstructions, with those on corresponding true AP radiographs. METHODS: CT shoulder scans were matched with true AP radiographs that were classified as either Suter-Henninger type A or C quality. 3D bony reconstructions were segmented from the CT scans, and rotated to replicate an ideal true AP view. Two observers performed CSA measurements using both CT and radiographic images. Measurements were repeated after a one week interval. Reliability was assessed using intraclass correlation coefficients (ICCs) and Bland-Altman plots [bias, limits of agreement (LOA)]. RESULTS: Twenty CT shoulder scans were matched. The mean CSA values were 32.55° (± 4.26°) with radiographs and 29.82° (± 3.49°) with the CT-based method [mean difference 2.73° (± 2.86°); P < 0.001; bias +2.73°; LOA -2.17° to +7.63°]. There was a strong correlation between the two methods (r = 0.748; P < 0.001). Intra-observer reliability was similar, but the best intra-observer values were achieved by the most experienced observer using the CT-based method [ICC: 0.983 (0.958-0.993); bias +0.03°, LOA -1.28° to +1.34°]. Inter-observer reliability was better with the CT-based method [ICC: 0.897 (0.758-0.958), bias +0.24°, LOA -2.93° to +3.41°]. CONCLUSION: The described CT-based method may be a suitable alternative for critical shoulder angle measurement, as it overcomes the difficulty in obtaining a true AP radiographic view.

Increased orthopaedic presentations as a result of COVID-19-related social restrictions in a regional setting, despite local and global trends.

BACKGROUND: The coronavirus (COVID-19) pandemic has affected the utilisation of emergency department (ED) services worldwide. The aim of this study was to assess the impact of COVID-19-related public health measures on orthopaedic presentations to a regional Australian hospital. METHODS: A case-control study was performed at a regional trauma hospital in New South Wales (NSW), Australia. Data was collected prospectively from patients that required orthopaedic review in the period corresponding to a declaration of a global pandemic to the end of the NSW lockdown, and compared with retrospective data from the corresponding period in 2019. The five-year average of orthopaedic presentations to ED during the study period were obtained for comparison. The primary outcomes were overall number of presentations, mechanism and anatomical location of injuries, operative versus non-operative management and disposition. RESULTS: During the study period in 2020, presentations requiring orthopaedic review were significantly more frequent than 2019 (496 vs. 280, p < 0.0001), with more requiring admission in 2020 (p < 0.0001). The absolute number of patients managed operatively was higher (p = 0.0002) and significantly more patients were referred for community follow-up (p < 0.0001). There was a 20% increase of consults in 2020 compared to the average number of referrals during the same period in the previous five years. CONCLUSIONS: Contrary to other published literature, lockdown conditions imposed during the COVID-19 pandemic resulted in a surprising 77% increase in orthopaedic presentations to this regional Australian hospital. These findings can be used to better direct resources, preparation and staff education in the current and for future pandemics.

Corrosion of 3D-Printed Orthopaedic Implant Materials.

3D-printing technologies such as electron beam melting (EBM) have allowed for patient-specific orthopaedic implants, however differences generated from the fabrication process may alter the corrosion properties of Ti6Al4V implants. This study evaluated the corrosion characteristics of EBM-fabricated Ti6Al4V, alongside any linked microstructural and surface changes. EBM-fabricated Ti6Al4V and wrought Ti6Al4V specimens (n = 10 per group) underwent microstructural and surface characterisation before and after corrosion testing. Cyclic potentiodynamic polarisation of specimens was conducted in accordance with ASTM Standard F2129-17. The degree of corrosion damage was subsequently assessed via qualitative and quantitative measures. EBM-fabricated Ti6Al4V demonstrated a higher proportion of ß phases and greater surface roughness, compared to wrought Ti6Al4V. Significant differences were observed for all corrosion parameters between the two groups. The lower breakdown potentials (Eb) for EBM-fabricated Ti6Al4V (2.035 V), compared to wrought Ti6Al4V (3.667 V), indicate a lower resistance to pitting corrosion. A greater resultant spread, and severity of corrosion damage was noted on wrought Ti6Al4V. An inferior in vitro corrosion resistance was observed for EBM-fabricated Ti6Al4V. Without post-processing, the rougher surface and differences in microstructure are likely to contribute to this. This suggests potential clinical implications upon in vivo implantation, although corrosion measures remain above recommended minimums.