|Beitragstitel||Does the Schoettle point in MPFL reconstruction clinically matter? A clinical and radiographic study|
The reconstruction of the medial patellofemoral ligament (MPFL) has become an important treatment option for recurrent patellar instability. Positioning of the femoral tunnel is a crucial step for restoring patellofemoral joint kinematics. The main objective of the current study was to correlate the femoral tunnel positioning with clinical outcome.
63 patients (23 +/- 7.7 years at the time of surgery, 79.4% female), who underwent MPFL-reconstruction for recurrent patellar instability, were included in this retrospective study. Mean follow-up was 5.6 +/- 3.2 years. The distance between the centre of the drill hole and the radiographic landmark for anatomic MPFL reconstruction (“Schoettle point”) was measured on true lateral conventional radiographs only and regarded as mal-positioned with a greater distance as 10mm. The distance was then correlated to subjective outcome measurements (Kujala score, relative knee score) and postoperative complications such as loss of range of motion, revision surgery, and recurrent instability. Furthermore, patellar height (Caton-Deschamps-Index), trochlear dysplasia, congruence angle and patellar dysplasia according to Wiberg were recorded.
The centre of the drill holes had an average distance of 13.3mm to the Schoettle point, and 32 out of 63 knees were found to be malpositioned. There was no correlation to be found with Kujala score, patients’ satisfaction or any patellofemoral measurement. However, four out of the five knees requiring mobilisation under femoral nerve catheter due to loss of range of motion showed a malpositioned femoral tunnel.
A malpositioned femoral tunnel in MPFL reconstruction will not necessarily lead to an adverse postoperative outcome however is associated with postoperative complications such as loss of range of motion. It seems warranted to analyse the influence on subjective outcome in function of other factors such surgical indication, graft tensioning, and patellar height.