Cutaneous Angiosome Territory of the Medial Femoral Condyle Osteocutaneous Flap

Abstract

The medial femoral condyle flap is used for treatment of nonunions with or without intercalary bone loss. Most reported uses have been without a skin segment, but this flap can provide a skin component supplied by the saphenous artery branch (SAB) of the descending genicular artery (DGA) pedicle. Experience with this flap suggests that an additional distinct, reliable, more-distal, DGA-cutaneous branch can be found at condyle level, capable of supporting skin without using the SAB. This cadaver study evaluated SAB and DGA-cutaneous branch angiosome territories. A clinical case series assesses the DGA-cutaneous branch's clinical utility. The DGA and SAB were isolated in 12 cadaveric legs, divided, and separately cannulated. Red dye and methylene blue were selectively injected into each vessel manually. Skin perfusion was measured and photographed. In all specimens, the DGA was present, originating 14.2 cm proximal to the joint line, and demonstrated a distinct cutaneous branch at condyle level. This vessel provided an average perfusion area of 70 cm(2), centered over the medial knee. The SAB was identified in 11 specimens (92%), with an average perfusion area of 361 cm(2) along the medial aspect of the distal thigh and proximal leg. The DGA communicating branch was present and used for perfusion of the skin paddle in 17 of 20 cases. The SAB was present in 18 of 20 cases, used with DGA-communicating branch in 4 cases, and the sole source of skin perfusion in 1 case. In 2 remaining cases, neither the SAB nor DGA communicating branch was adequate for perfusion of a skin segment. The medial femoral condyle flap can be harvested with a large skin paddle based on the SAB. A smaller skin segment can be harvested using the more distal DGA-communicating branch at condyle level. Improved understanding of the skin island associated with the DGA's saphenous and cutaneous branches can provide a rapid, reliable method of skin-segment harvest.