Anatomical femoral tunnel positioning in the medial patellofemoral ligament reconstruction: is the free-hand technique accurate?

BACKGROUND: During medial patellofemoral ligament (MPFL) reconstruction, achieving anatomical positioning of the femoral and patellar origins is important for restoration of patellofemoral biomechanics. Although visual and manual detection can also be used to determine the femoral point of the MPFL, minimal research exists regarding accuracy of this method. Our aim was to evaluate the accuracy of free-hand method in determining the femoral point of the MPFL during surgery. METHODS: A prospective analysis was completed with 19 patients (20 knees), age ranging 15 to 39 years, in whom, three orthopedic surgeons with experience in knee procedures performed surgical reconstruction of the MPFL. MPFL femoral origin was accessed in a free-hand technique and a strict lateral view of the knee was then obtained. If the selected point was not considered appropriate, a better position was identified following the criteria set forth by Schottle. RESULTS: In a mean clinical follow-up of 2.3±1.3 years, anatomical point was achieved using the free-hand palpation method in seven knees (28.5%). Among the thirteen knees for whom the anatomical point was not attained without fluoroscopy, the mean error pattern found was 27.5%±8.6% for proximal (P-D axis) and 24%±6.3% for anterior in the posterior-anterior axis. The average error (difference between the marked point and the anatomical point) was 20.6%±5.9% (P=0.98) for the distal-proximal axis and 15.9%±6.1% (P=0.77) for the posterior-anterior axis. CONCLUSIONS: The anatomical palpation technique showed low accuracy, even when performed by experienced surgeons. The most common error pattern observed was proximal and anterior.