Reduced-dose computed tomography is the most accurate method to measure ceramic hip resurfacing cup version

Alvise Saracco, Alberto Grassi, Matteo Romagnoli, Lawrence Camarda, Kartik Logishetty, Stefano Zaffagnini, Justin Cobb

Research output: Contribution to journalArticlepeer-review


BACKGROUND: A precise assessment of cup version after hip resurfacing is generally requested, especially in clinical trials or in case of complications.

AIMS: To identify which diagnostic imaging modality, between AP pelvis X-rays, the AP Pelvis CT Scout image and reduced-dose axial CT scan, is the most precise to assess cup version of an all-ceramic hip resurfacing implant in a first-in-human clinical trial.

METHODS: We retrospectively assessed the cup version of the first 20 patients who underwent an experimental all-ceramic hip resurfacing on AP pelvis X-rays (0.8 mSv of radiation), AP pelvis CT scout images (0.016 mSv) and axial CT slices performed using a reduced dose protocol (0.3 mSv). The intra-observer and inter-observer reliabilities were calculated.

RESULTS: Reduced dose Pelvis CT scan was the most precise imaging modality to detect cup version (Pearson Correlation Coefficient, PCC = 0.98, p < 0.001). The AP Pelvis CT Scout image was found to be sufficient to measure cup version within an acceptable margin of tolerance (mean difference ± 4.7° from pelvis CT scan) and highly correlated to axial pelvis CT scan measurements (PCC 0.97, p < 0.001). Analysis of cup version from AP X-rays poorly correlated with measurements from Pelvis CT (PCC 0.59, p = 0.006).

CONCLUSIONS: Due to lower radiation exposure and highest accuracy, reduced dose CT is a valid modality to measure acetabular cup version after ceramic hip resurfacing. Plain X-rays are not accurate nor precise to measure version, whereas high agreement of measurements between AP Pelvis CT Scout and axial pelvis CT scan was found.

Original languageEnglish
Pages (from-to)1-7
Number of pages7
JournalEuropean Journal of Radiology
Early online dateMay 4 2020
Publication statusPublished - Jul 2020


  • CT scout view
  • CT/low dose
  • Hip joint/cup version
  • Hip joint/replacement
  • Hip joint/resurfacing
  • X-rays/radiographs


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