Pre-contoured Plate Fit Assessment for Acetabular Fractures.

Purpose: Insufficient fitting of pre-contoured plates for acetabular fractures might lead to inadequate fracture reduction, but it is unclear in which patients pre-contoured plates fit adequately. The aims of this study were to assess plate fitting in sex- and height-specific anatomical variations of the hemipelvis, and categorizing the outcomes as moderate or good fit.

Methods: 3D models from computed tomography (CT) scans were obtained from a dataset of 200 patients with an intact left hemipelvis. This dataset was divided into eight subgroups, based on sex and body height, and the plate was virtually fitted on each shape. Plate fitting was assessed by computing the iliopectineal line, the quadrilateral slope, and the root mean square distance (RMSD) between each coordinate of the plate and its closest coordinate on the hemipelvis.

Results: The mean age was 56 ± 16 years, and the mean height was 173 ± 10 cm. All female pelves had a moderate fit, mainly because the plate length either exceeded the iliopectineal line length, or the plate's anterior aspect was directed too ventrally. Three out of four male pelves had a good fit. Only the small height subgroup (<175 cm) showed a moderate fit due to the plate length exceeding the iliopectineal line length and a relatively high median RMSD value (1.5 [0.8-2.0] mm) in mid-section of the plate.

Conclusions: In acetabular fracture surgery, both visual and quantitative evaluation of suprapectineal plate fitting in sex- and body height-specific subgroups showed moderate fitting in female pelvic shapes, indicating a need for substantial intraoperative bending. This suggests the need for different sizes and contours of future suprapectineal plates in acetabular fracture surgery.