Review Question - QID 212162

If a graft becomes tighter with knee flexion, the femoral attachment was placed too proximal as would be the case with position A.

The medial patellofemoral ligament inserts on to the femur between the medial epicondyle and the adductor tubercle. This position can be identified radiographically using Schottle’s point as depicted in Illustration A, and is paramount to the outcome of the procedure. If after reconstruction the graft becomes tighter with knee flexion the femoral attachment was placed too proximally. This error is referred to as “high and tight” and results in a loss of knee flexion or graft failure. Conversely, a femoral attachment site that is placed too distally will result in a graft that is too loose with knee flexion (“low and loose”).

Stephen et al review the position of the femoral attachment and its relationship to contact forces following MPFL reconstruction. They report graft over tensioning or femoral tunnels positioned too proximal or distal caused significantly elevated medial joint contact pressures and increased medial patellar tilting. They conclude that these errors will result in early degenerative changes and/or pain.

Burrus et al review the position of correct graft placement during MPFL reconstruction, and how to properly identify this position in the operating room. They report that if the graft is found to be too tight with flexion, the surgeon has positioned the graft too proximally on the femur. Furthermore, if the graft loosens with knee flexion, it has been placed to distally. They conclude that these simple rules should be followed for troubleshooting graft position intraoperatively.

Figure A is the lateral radiograph of the knee. Illustration A demonstrates the correct location for Schottle’s point, which also corresponds with position B in Figure A.

Incorrect Answers:
Answer 2: Position B represents Schottle’s point and is the correct position for the femoral attachment.
Answer 3 & 4: Position C and D are too distal and would result in a graft that was too loose.
Answer 5: While this position is too posterior, it would not produce a graft that is tighter in flexion than one in position A.