Georg Osterhoff1,2, Andreas Petersik3, Kai Sprengel1, Hans-Christoph Pape1. 1. Department of Trauma, University Hospital Zurich, Zürich, Switzerland. 2. Department of Orthopedics, Trauma and Plastic Surgery, University Hospital Leipzig, Leipzig, Germany. 3. Research & Development, Trauma & Extremities division, Stryker Trauma GmbH, Schoenkirchen, Germany.
Abstract
OBJECTIVE: To quantify intrapelvic surface symmetry in reference to a preshaped suprapectineal acetabular implant. METHODS: In this cross-sectional study, an anatomically preshaped acetabular fracture implant was fitted on 3D surface models of 516 pelvises from a preexisting bone database using a software tool for automated implant fitting (SOMA, Stryker Orthopaedic Modeling and Analytics) of a CAD model of the implant. The distances between bone and the reference implant were measured at 2310 reference points for each hemipelvis. RESULTS: The average distance between the left hemipelvis and the plate was 1.98 mm (median, 10% percentile: 1.45, 90% percentile: 2.78) and 2.0 mm (median, 10% percentile: 1.45, 90% percentile: 2.92) between the right hemipelvis and the plate. There was no significant difference between the 2 hemipelvises (median absolute pairwise delta: 0.25 mm; 10% percentile: 0.04, 90% percentile: 0.82; Wilcoxon, P = 0.064). CONCLUSIONS: With regard to the periacetabular surface of the inner pelvis, the pelvis can be considered sufficiently symmetric for using the mirrored contralateral hemipelvis as a template for patient-specific implants in acetabular fracture fixation.
OBJECTIVE: To quantify intrapelvic surface symmetry in reference to a preshaped suprapectineal acetabular implant. METHODS: In this cross-sectional study, an anatomically preshaped acetabular fracture implant was fitted on 3D surface models of 516 pelvises from a preexisting bone database using a software tool for automated implant fitting (SOMA, Stryker Orthopaedic Modeling and Analytics) of a CAD model of the implant. The distances between bone and the reference implant were measured at 2310 reference points for each hemipelvis. RESULTS: The average distance between the left hemipelvis and the plate was 1.98 mm (median, 10% percentile: 1.45, 90% percentile: 2.78) and 2.0 mm (median, 10% percentile: 1.45, 90% percentile: 2.92) between the right hemipelvis and the plate. There was no significant difference between the 2 hemipelvises (median absolute pairwise delta: 0.25 mm; 10% percentile: 0.04, 90% percentile: 0.82; Wilcoxon, P = 0.064). CONCLUSIONS: With regard to the periacetabular surface of the inner pelvis, the pelvis can be considered sufficiently symmetric for using the mirrored contralateral hemipelvis as a template for patient-specific implants in acetabular fracture fixation.