A detailed anatomical description of the subvastus region and its clinical relevance for the subvastus approach in total knee arthroplasty

The subvastus region and its anatomical contents are important when performing a total knee replacement via a subvastus approach. Thirty-two human cadaver thighs were studied to provide a detailed anatomical description of the subvastus region and its contents, namely the descending genicular artery and its branches, and the saphenous nerve proximally. In 24 specimens the descending genicular artery arose from the femoral artery and divided into osteoarticular and saphenous branches, while in eight specimens it was absent. The osteoarticular and saphenous branches arose independently from the femoral artery. On the basis of these distribution patterns nine variations with regard to the number and origin of the muscular, musculoarticular and saphenomusculoarticular branches arising from these vessels could be identified. The musculoarticular branch should be preserved wherever possible; however, if it must be sacrificed to improve exposure of the knee joint via a proximal extension of the incision, the passage of the saphenous nerve and the saphenous branch through the vastoadductor membrane are additional structures which must be considered. The proximal limitation for the mobilisation is the adductor hiatus, with further mobilisation increasing the risk of damaging the femoral artery and vein.