PLoS ONE (Jan 2023)

Validation of direct CT measurement of malrotation in femoral neck fractures: A bone model study.

  • Emmanouil Liodakis,
  • Gesa Helen Pöhler,
  • Lena Sonnow,
  • Philipp Mommsen,
  • Jan-Dierk Clausen,
  • Tilman Graulich,
  • Alexander Maslaris,
  • Mohamed Omar,
  • Timo Stübig,
  • Stephan Sehmisch,
  • Tarek Omar Pacha

DOI
https://doi.org/10.1371/journal.pone.0278850
Journal volume & issue
Vol. 18, no. 4
p. e0278850

Abstract

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BackgroundWhile postoperative malrotation in the subtrochanteric region is a well-known problem, malrotation after osteosynthesis in proximal femoral fractures has not been extensively studied. In this context, many methods for perioperatively assessment of femoral torsion have been described, but none of them is applicable in the basicervical region of the proximal femur. As an important difference in femoral neck fractures, the discontinuous neck fails to serve as a significant "pointer" for measurements and malfunctions to be placed in relation to the condylar plane. Considering postoperative maltorsion at any location as a substantial negative effect on patients' outcome and functional expectations, precise and patient-friendly rotation measurement standards in femoral neck fractures are desired in clinical practice. Recently, a novel computed tomography (CT) based geometric technique was described named "direct measurement" with promising results covering this diagnostic disparity, but still requires validation. Thus, we aimed to validate the previously described technique using a controlled range of displacement in a femoral neck fracture Sawbone® model.Methods and findingsA goniometer was designed to set retro- and anteversion of the proximal femur in a reproducible manner. Prospectively, all femurs underwent a CT scan and were measured 3D for displacement. The interclass correlation between the CT measurements and the goniometer measurements was calculated and was found to be very high (1.00, 95% confidence interval: 0.99-1.00; p ConclusionThis CT-based 3D measurement technique may allow for perioperative malrotation assessment in basicervical femoral neck fractures and appears to be feasible in femoral neck fractures when it comes to rare cases of osteosynthesis. Further investigations are still needed to define the thresholds of malrotation provoking functional impairment after osteosynthesis in basicervical femoral neck fractures.