Medial Femoral Trochlea Osteochondral Graft: A Quantitative Anatomic Comparison to the Proximal Pole of the Scaphoid.

Abstract

Background Treatment of scaphoid proximal pole (SPP) nonunion with a vascularized osteochondral graft from the medial femoral trochlea (MFT) has been described, with positive outcomes thus far. However, our understanding of the congruency between the articular surfaces of these structures is incomplete. Objective Our purpose was to evaluate the congruency of the MFT and SPP using a quantitative anatomical approach. Methods The distal femur and ipsilateral scaphoid were dissected from 12 cadavers and scanned with computerized tomography. Three-dimensional models were created and articular surfaces were digitally "dissected." The radius of curvature (RoC) of the radioulnar (RU) and proximodistal (PD) axes of the SPP and MFT, respectively, as well as the orthogonal axes (SPP, anteroposterior [AP]; MFT, mediolateral [ML]) were calculated. The RoC values were compared using the Wilcoxon signed-rank test. Results The RoC values for the SPP and MFT were not significantly different in the RU-PD plane ( p = 0.064). However, RoC values for the SPP and MFT were significantly different in the AP-ML plane ( p = 0.001). Conclusions For most individuals, the RU curvature of the SPP was similar to the PD curvature of the MFT. For nearly all individuals, the AP curvature of the SPP and the ML curvature of the MFT shared less congruence. Clinical Relevance Articular surface congruity may not be a critical factor associated with improvements in wrist function following this procedure.