The MFT osteochondral flap, provides a convex cartilaginous segment of bone with an arc of curvature very similar to that of the greater curvature of the proximal scaphoid. A segment of osteochondral bone is harvested in continuity with the transverse branch of the descending geniculate artery. The source vessel is the same as the conventional MFC corticoperiosteal flap (Fig. 20.3). However, the MFT’s terminal branch (transverse branch) is distinct from the longitudinal branch typically used for the MFC flap. The osteochondral segment is harvested to mimic the deficit created after resection of the proximal pole fragment and additional portions of the proximal scaphoid beyond the nonunion site (Fig. 20.4).

This resection of additional scaphoid distal to the nonunion site converts the proximal pole nonunion conceptually into a waist-level osteosynthesis site. During resection of the proximal scaphoid, cartilage on the lesser curvature that articulates with the midcarpal joint is preserved. Additionally, the distal-most segments of the dorsal and volar scapholunate interosseous ligament are likewise preserved if possible. Preservation of the thin cartilage layer and distal scapholunate ligament is facilitated by maintaining the capsular integrity of the midcarpal joint. The resection is completed with the goal of opening only the radicarpal joint. The only cartilage-bearing surface of the medial femoral trochlea flap is oriented to articulate solely with the scaphoid fossa of the radius (Fig. 20.5).