Magnetic Resonance Imaging to Investigate the Clinical Applicability of the Medial Femoral Trochlea Osteochondral Flap Within the Wrist

Background: The medial femoral trochlea (MFT) osteochondral flap is employed for reconstruction of unsalvageable scaphoid proximal pole nonunions. The convex surface of the cartilage-bearing proximal trochlea is used to replace the similarly contoured proximal scaphoid and articulate with the concave scaphoid fossa of the radius. A magnetic resonance imaging (MRI) comparison of the shape of the MFT as it relates to the native proximal scaphoid has not been previously performed. Our study aimed to quantifiably compare the shape of the MFT, proximal scaphoid, and scaphoid fossa. Methods: Using imaging processing software, we measured radius of curvature of the articular segments in MRI scans of 10 healthy subjects’ wrists and knees. Results: Compared with the scaphoid fossa, average ratio of the radius of circumference of the proximal scaphoid was 0.79 and 0.78 in the coronal and sagittal planes, respectively. Compared with the scaphoid fossa, average ratio of the radius of circumference of the MFT was 0.98 and 1.31 in the coronal and sagittal planes, respectively. The radius of curvature of the MFT was larger than the proximal scaphoid, in the coronal and sagittal planes. In the coronal plane, the MFT radius of curvature is nearly identical to the scaphoid fossa, a closer match than the scaphoid itself. In the sagittal plane, the radius of curvature of the MFT was larger than the radius of curvature of the scaphoid fossa. Conclusions: Our data suggest that the radius of curvature, in the sagittal and coronal planes, of the MFT and proximal scaphoid is disparate.