Abstract
Background:
During the past two decades the medial Patellofemoral ligament has come to the fore as the essential lesion of acute patella dislocation and its reconstruction in cases of chronic instability seems logical. The femoral insertion of the medial Patellofemoral ligament (MPFL) is key to the isometry or desired anisometry of the reconstruction. Radiographic landmarks for the femoral insertion has been described in literature most notably by Schottle et al. AJSM 2007. We examined the consistency of these landmarks of the femoral insertion of the MPFL.
Methods:
24 unpaired knees of cadavaric specimen were dissected for the origin of the MPFL.
A radiographic marker was then placed in the centre of the femoral attachment of the MPFL and a direct lateral X-ray obtained of the distal femur. The sweet spot was defined according to the landmarks described by Schottle et al and deviation from the sweet spot was measured.
Results:
The average distance from the centre of the described radiological centre of the MPFL was 5.4 mm. In six cases the ligament insertion was 5.6 mm distal to the ideal radiological centre. We did not find the origin of the MPFL to be a consistent radiological landmark due to a wide insertion of the ligament on the femur with a variable anisometric centre.
We recommend dynamically testing the insertion site of the MPFL around a guide wire inserted into the femur instead of relying solely on the radiological position.
