Biomechanical evaluation of an anatomic double-bundle posterior cruciate ligament reconstruction.
OBJECTIVE
The purpose of this study was to evaluate the effect of the anatomic double-bundle reconstruction (ADBR) of the posterior cruciate ligament (PCL) with 2 femoral tunnels and 2 tibial tunnels.


METHODS
Eight fresh-frozen human knees were used. Bone tunnels were created based on the PCL anatomic footprints. A 9-mm looped semitendinosus and gracilis tendon for anterolateral bundle reconstruction (ALR), a 7-mm looped semitendinosus tendon for posteromedial bundle reconstruction (PMR), and the same grafts for the ADBR were used. Under a 100-N posterior tibial load and under a 100-N posterior tibial load and 5 Nm of external tibial torque, the posterior tibial translation (PTT) was measured.


RESULTS
Under posterior tibial load, at 0°, the PTT of the ALR was larger than that of the intact knee (P = .04) and the ADBR (P = .03); however, there were no significant differences between the PTT of the PMR and that of the ADBR (P = .28) and intact knee (P = .99). At 30°, the PTT of the ADBR was smaller than that of the ALR (P = .02) and PMR (P = .02). At 60°, the PTT of the PMR was larger than that of the ADBR (P = .02). At 90°, the PTT of the PMR was larger than that of the ADBR (P = .02). Under posterior tibial load and external tibial torque, at 0°, the PTT of the ALR was larger than that of the ADBR (P = .04).


CONCLUSIONS
Although the graft size of the ADBR was larger than other reconstructions, the ADBR was better than the ALR at 0° and 30° of knee flexion under the posterior tibial load and at 0° under the combination of posterior tibial load and external tibial torque, as well as better than the PMR at 30°, 60°, and 90° of knee flexion under the posterior tibial load.


CONCLUSIONS
The clinical outcome of PCL reconstruction might improve by reducing posterior knee laxity in knee extension with the ADBR.
Department of Orthopaedic Surgery, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. hare1018@cc.hirosaki-u.ac.jp
Harehiko
H
Tsukada
Yasuyuki
Y
Ishibashi
Eiichi
E
Tsuda
Akira
A
Fukuda
Yuji
Y
Yamamoto
Satoshi
S
Toh
D000368:Aged; D001696:Biomechanical Phenomena; D006801:Humans; D066298:In Vitro Techniques; D007719:Knee Joint / Q000503:physiopathology; D008875:Middle Aged; D016119:Posterior Cruciate Ligament / Q000503:physiopathology* / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods; D013977:Tibia / Q000503:physiopathology; D019415:Torque