Regarding “Patellar Tendon Reconstruction for Chronic Patellar Tendon Rupture Using Hamstring Tendons: The Reverse Double Figure‐of‐Eight Technique”

We read with interest the publication by Mouarbes et al.1 describing “The Reverse Double Figure-of-Eight Technique” for patellar tendon reconstruction surgery for chronic patellar tendon ruptures. In their technique, the semitendinosus and gracilis grafts are harvested in the standard manner while keeping them attached to their tibial insertion. Then, transverse patellar and tibial tunnels are prepared, followed by passing the semitendinosus and gracilis grafts through these tunnels forming a reverse figure-of-eight configuration. The authors indicated that this configuration provides a robust and anatomically accurate reconstruction, keeping hamstring tendons attached to their tibial insertions, preserving the bone stock without the need for screw fixation. In addition, the authors acknowledged the importance of minimizing patellar fracture risk by recommending tunnel placement through the middle portion of the patella and by emphasizing preservation of patellar bone stock. We commend the authors for their efforts in introducing a new technique to the surgical literature. However, we would like to raise technical concerns regarding the described patellar tunnels and their association with patellar fractures. Studies about patellar tunnels have focused on medial patellofemoral ligament reconstruction. In their cadaveric study, Bonazza et al.2 identified that transosseous patellar tunnels that “breach the anterior cortex” (as in full transverse tunnels) are more likely to result in fractures through the tunnel under load. Deasey et al.3 found that small, oblique, and short tunnels were associated with a very low incidence of patellar fracture. These studies support that transverse bone tunnels through the patella significantly increase fracture risk. In the technical note by Raoulis et al.,4 complete transverse tunnels act as stress risers, and they concluded that vertically oriented tunnels preserve more bone stock in the anterior cortex of the patella and minimize stress compared with full transverse tunnels. In their study using 36 sawbones models, Hapa et al.5 highlighted that patellar fixation using transverse tunnels carries the risk of patellar fracture. Based on these findings, we suggest that a single complete transverse tunnel sacrifices more bone stock compared with 2 push-lock holes. We believe the primary concern may not only be tunnel diameter or bone loss itself but also the orientation of the tunnel relative to the physiological force vectors acting on the patella. Vectors of the forces generated by the patellar tendon and quadriceps tendon on the patella are vertical. Therefore, longitudinal distractive forces acting across a transverse tunnel configuration may increase biomechanical stress within the patella and predispose to transverse fracture patterns. We prefer complete vertical tunnels for graft passage or partial vertical tunnels which have enough length for push-lock anchor placement. The graft is either passed through the complete vertical tunnels and then tied superiorly above the patella or attached to the inferior pole of the patella using 2 push-lock anchors. This technique provides transmission of forces through tunnels which are parallel to the vectors of forces created by patellar and quadriceps tendons, thus providing a more biomechanically stable reconstruction without the potential of creating a patellar fracture. The authors (T.K.Ü., O.Ç., B.K.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.