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. 2023 Dec;33(8):3703-3709.
doi: 10.1007/s00590-023-03616-9. Epub 2023 Jun 14.

Standard versus low-dose computed tomography for assessment of acetabular fracture reduction using novel step and gap measurement technique

Abrianna S Robles  1 , Amit S Piple  2 , Donald J DeSanto  3 , Ashley Lamb  2 , Stephen J Gibbs  4 , Nathanael D Heckmann  2 , Geoffrey S Marecek  3
Affiliations

Standard versus low-dose computed tomography for assessment of acetabular fracture reduction using novel step and gap measurement technique

Abrianna S Robles et al. Eur J Orthop Surg Traumatol. 2023 Dec.

Abstract

Purpose: Quality of reduction is of paramount importance after acetabular fracture and is best assessed on computed tomography (CT). A recently proposed measurement technique for assessment of step and gap displacement is reproducible but has not been validated. The purpose of this study is to validate a well-established measurement technique against known displacements and to determine if it can be used with low dose CT.

Methods: Posterior wall acetabular fractures were created in 8 cadaveric hips and fixed at known step and gap displacements. CT was performed at multiple radiation doses for each hip. Four surgeons measured step and gap displacement for each hip at all doses, and the measurements were compared to known values.

Results: There were no significant differences in measurements across surgeons, and all measurements were found to have positive agreement. Measurement error < 1.5 mm was present in 58% of gap measurements and 46% of step measurements. Only for step measurements at a dose of 120 kVp did we observe a statistically significant measurement error. There was a significant difference in step measurements made by those with greater and those with fewer years in practice.

Conclusion: Our study suggests this technique is valid and accurate across all doses. This is important as it may reduce the amount of radiation exposure for patients with acetabular fractures.

Keywords: Acetabular fractures; Computed tomography; Gap; Measurement technique; Posterior wall; Step.

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Conflict of interest statement

Heckmann Disclosures: AAOS committee member, AJRR committee member, American Association of Hip and Knee Surgeons committee member. Intellijoint Surgical: Paid consultant; Stock Options. MicroPort Orthopedics: Paid consultant. Marecek Disclosures: BoneSupport AB: Paid consultant, DePuy, A Johnson & Johnson Company: Paid consultant. Globus Medical: IP royalties; Paid consultant. Nuvasive: Paid consultant. Orhtofix, Inc: Paid consultant. Orthopaedic Trauma Association: Board/committee member. Restor3d: Paid consultant; stock or stock options. Western Orthopaedic Association: Board/committee member. Zimmer: Paid consultant.

Figures

Fig. 1
Fig. 1
Gap and Step Measurement Technique. a gap displacement measurement at 80 kVp, b gap displacement measurement at 120 kVp, c step displacement measurement at 80 kVp, d step displacement measurement at 120 kVp
See this image and copyright information in PMC

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