Where is Schöttle’s point, the radiographic landmark for locating the femoral attachment of the medial patellofemoral ligament during MPFL reconstruction?

Schöttle's Point Location

Schöttle's point is located approximately 1 mm anterior to the posterior cortex extension line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to the posterior point of Blumensaat's line on a true lateral radiograph of the knee. 1, 2

Radiographic Identification Method

The original Schöttle method identifies this femoral landmark on a true lateral knee radiograph using the following coordinates 2:

• 1 mm anterior to the line representing the extension of the posterior cortex of the femur
• 2.5 mm distal to the posterior origin of the medial femoral condyle
• Proximal to the posterior point of Blumensaat's line (the roof of the intercondylar notch)

Alternative Anatomic Landmark Method

A more recent anatomic approach uses palpable bony landmarks without fluoroscopy 1:

• 8 mm distal to the apex of the adductor tubercle (the most convex point)
• 8 mm anterior to the posterior edge (the posteromedial cortex edge in the transition area between medial condyle and femoral shaft)
• This method achieved 93.6% accuracy (44/47 tunnels) in proper zone placement 1

Critical Limitations and Pitfalls

The radiographic method is inherently imprecise and should not be used as the sole determinant of femoral tunnel placement. 3 Multiple studies demonstrate significant concerns:

• Only 38% of knees achieved >50% overlap between radiographic and anatomic tunnel positions 3
• The actual anatomic MPFL insertion averages 3.8 mm posterior and 4.4 mm distal to Schöttle's point in patients with recurrent patellar dislocation 4
• All three commonly cited radiographic reference points (Schöttle, Redfern, Fujino methods) averaged >5 mm distance from the true anatomic saddle sulcus where the MPFL attaches 5
• Female patients with severe trochlear dysplasia show even less accuracy with the radiographic method 3

Anatomic Reality: The Saddle Sulcus

The true anatomic MPFL attachment occurs at the saddle sulcus, which is located 5:

• 11.7 mm from the adductor tubercle apex toward the medial epicondyle (approximately 60-63% of the distance between these landmarks)
• 5.6 mm perpendicular-posterior to the border connecting the adductor tubercle and medial epicondyle apexes
• This represents the most isometric point with only 2.1 mm mean length change from 0° to 110° flexion 2

Clinical Recommendation

Direct palpation of the saddle sulcus using the adductor tubercle and medial epicondyle as landmarks is more accurate than relying solely on radiographic reference points. 5 Nonanatomic placement causes significant loss of isometry—proximal placement causes up to 6.4 mm lengthening and distal placement causes up to 9.1 mm shortening through flexion, both significantly compromising graft function. 2