Figure 4. Determining femoral MPFL isometric point: Small circle represent point on vertical line from posterior femoral cortex, midway between horizontal line extending from cortex-metaphyseal flare junction and posterior-most aspect of Blumensaat line. Large circle represent femoral tunnel. Tunnel deemed accurately placed if within 9 mm of our isometric MPFL point. (Reproduced and modified with permission from Schottle PB, Schmeling A, Rosenstiel N, Weiler A. Radiographic landmarks for femoral tunnel placement in medial patellofemoral ligament reconstruction. Am J Sports Med. 2007;35(5):801-804.).