Arthroscopic lateral retinacular release can be complicated by hemarthrosis in 10 to 18% of cases. The vascular structures involved are the lateral vascular pedicles of the knee. This study examines the topography of these pedicles. Anatomic and radioanatomic studies carried out in 50 specimens defined the route of the vascular pedicles at the lateral aspect of the knee. From the measurements carried out, we noted the relative homogeneity of the routes taken by the different proximo-lateral vascular pedicles, which are highly vulnerable, and the variability of the disto-lateral arterial routes. A tracing-paper study identified two distinct routes for the disto-lateral vascular pedicle and evaluated the risk of injury to it in surgical approaches to the lateral aspect of the knee. Finally, the topographic data of the study suggest the possibility of preventive hemostasis of the proximo-lateral pedicle via a minimal approach close to the patella. Furthermore, it seems possible to avoid cutting the disto-lateral pedicle if it is localised by cutaneous trans-illumination at the beginning of the operation.