The Limits of Medial Femoral Condyle Corticoperiosteal Flaps

Abstract

The medial femoral condyle (MFC) vascularized corticoperiosteal flap has been well described for the treatment of nonunion with minimal bone loss. Recent applications of this donor site as a corticocancellous flap for large intercalary defects bring into question the vascular territory of bone supplied by the descending genicular artery (DGA). This study's purpose is to delineate the proximal extent of periosteal blood supply of the medial column of the femur provided by the DGA system. In 18 cadaveric specimens, the DGA was isolated, measured, and cannulated. Using subtraction techniques of fluoroscopic angiography, the vascular network and proximal-most extent of periosteal perfusion were recorded using radiopaque contrast dye. The DGA branched from the superficial femoral artery 14.2 ± 2.4 cm proximal to the joint line of the knee. The length of the vascular pedicle to its attachment onto the periosteum was 7.7 ± 2.2 cm. All specimens demonstrated a filigree of periosteal vessels dominated by a transverse and a longitudinal branch at the level of the condyle. Proximal perfusion was consistently noted by a large, longitudinal medial metaphyseal periosteal artery. The medial metaphyseal periosteal artery demonstrated that the proximal-most perfusion of the DGA was 13.7 ± 1.3 cm proximal to the joint line. Average femur length was 47.1 ± 3.1 cm. The DGA provided perfusion of 29% ± 2% of the total length of the medial femur. The DGA provides a large and reliable region of periosteal perfusion, suggesting that corticocancellous MFC harvest might provide the benefits of vascularized bone for large, intercalary nonunion defects conventionally treated with fibula flaps. Harvest of MFC osseous flaps extending up to 13.7 cm proximal to the joint line can be perfused from the DGA pedicle. The MFC donor site might, therefore, be a reliable option for vascularized reconstruction of larger bone defects.