Member of the study group, Joan C. Monllau, MD, analyzed a series of 36 MPFL reconstructions (mean follow up 37.6 months, range 27 months to 74.5 months) with gracilis tendon autograft using the adductor magnus tendon as a pulley for femoral fixation and found good clinical results and without signs of patellofemoral osteoarthritis.
Here are five takeaways:
1. The study found the mechanical behavior of the graft determines success or failure of non-anatomic MPFL reconstructions. The graft is isometric between 0 degrees and 30 degrees (less than 5 mm of length difference between both knee flexion angles). Beyond 60 degrees of knee flexion, the graft became progressively lax and isometry is lost.
2. MPFLs must function as a tether in early flexion without being tight at any point if the patella is centered in the groove, and this can be achieved through non-anatomic attachments. However, to achieve this aim, researchers must do several proofs intraoperatively to evaluate the mechanical behavior of the graft, which increases surgical time.
3. Make a large enough incision to unequivocally identify the most important anatomic landmark, the adductor tubercle, for accurate anatomic femoral graft placement during MPLF reconstruction.
4. Results show that the femoral attachment of the MPFL is distal to the apex of the adductor tubercle and parallel with the long axis of the femur, the mean linear distance between the two points being 10.6 mm and the position of the insertion site is consistent in all knees.
5. In conclusion, the studies of normal cadavers cannot be assumed to reflect anatomy in recurrent dislocators, and radiographic landmarks are not accurate enough.
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