Medial Patellofemoral Ligament Reconstruction Using Adductor-Transfer and Adductor-Sling at Nonanatomic Femoral Attachment Sites Leads to Unfavorable Graft-Length Change Patterns: A Descriptive Biomechanical Study

Editorial Commentary: The Medial Patellofemoral Ligament Is Not Isometric and Anatomic Reconstruction Is Important, But Just a Small Piece of the Patellar Instability Puzzle

“…The resulting anisometry of the adductor sling and transfer techniques creates continued tensioning of the graft as knee flexion increases, which may put the graft at risk for failure or limit knee flexion motion. The findings reported by Xu et al 12 are consistent with prior studies that noted graft anisometry using more proximal femoral attachments in biomechanical models. 13,14 However, these findings must be considered in the setting of an evolving understanding of the native MPFL anatomy, as well as the effects of frequent concomitant pathology occurring in patients with recurrent patellar instability, such as patella alta, genu valgum, and axial malalignment, including tibial tubercle-trochlear groove (TT-TG) distances and excessive femoral anteversion.…”

The adductor magnus tendon is a viable option for medial patellofemoral ligament reconstruction, but with a busy surrounding neurovascular topography

“…Several previous studies have mentioned the presence of neurovascular structures around the harvesting area of the ADM tendon, though very few have described their topographical relationship with the tendon in detail. The usage and minimally invasive harvesting of the ADM tendon for the reconstruction of a ruptured MPFL has gained increasing attention in the last decade [8, 14, 16]. Independent of which harvesting technique is used, partial harvesting will eventually be enough for a stable and isometric patellar fixation [9, 16].…”

“…All specimens were measured and dissected with local law approval. Previous similar research [6, 16] has established a sample size of 8–12 specimens to be adequate for statistically significant measurements and outcomes. This study used a total of eight pairs (16 knees) of formalin‐fixed cadaver lower extremities.…”

“…Numerous techniques have been described in the literature for the reconstruction of the MPFL, mostly using an autograft. The most commonly preferred graft is one of the two hamstring tendons (the gracilis or the semitendinosus), but studies have also shown good results with the partial quadriceps tendon, the patellar tendon, and the adductor magnus tendon [10, 16, 17]. Considering that the majority of patients are young and most of them still have active growth plates, "dynamic" MPFL reconstructions have been suggested as a more suitable option for this age group.…”

“…In a dynamic reconstruction, the native proximal end of a given autograft (hamstring, quadriceps, or adductor magnus) is preserved, while the distal end is harvested and used for the surgical procedure. Given the proximity of the attachment of the adductor magnus (ADM) tendon to the native femoral footprint of the MPFL, there has recently been increasing interest in its use as an autograft [6, 16].…”