Patellofemoral Contact Area Validation

Purpose: To develop and validate short axial and sagittal MRI scans (<1min) to assess in vivo patellofemoral contact areas in loaded knee flexion. Materials and Methods: Contact area was assessed in four cadaver knee specimens from axial and sagittal scans using two contact area extraction techniques (‘delineation’ and ‘intersection’) and three calculation techniques (slice thickness multiplication, linear interpolation and spline interpolation). Error was expressed as the mean absolute and percentage difference from a dye staining-based reference standard. Intra-reader and intra-subject repeatability, expressed as the mean standard deviation, was determined. Results: Contact area assessments from the sagittal MRI scans using the delineation and slice thickness multiplication technique had the smallest error (47.7±38.1mm2 or 10.7%). The intra-reader repeatability from assessments using the sagittal scans was smaller than those using the axial scans when the delineation method was used (<9.4±4.3mm2 and