Posterolateral corner reconstruction using hamstrings grafts—A comparative biomechanical study of three techniques
Marcos Barbieri Mestriner, Shuntaro Nejima, Petra Bonacic Bartolin, Ricardo de Paula Leite Cury, Nilson Roberto Severino, Andrew A. AmisAbstract
Purpose
To compare three posterolateral corner (PLC) reconstruction techniques—the popliteofibular loop (PFLoop), the modified LaPrade (LP) and modified Arciero (AR) techniques—in restoring knee laxity in varus (VR), external tibial rotation (ER) and posterior tibial translation (PTT).
Methods
Nine cadaveric knees were subjected to 8Nm VR, 5Nm ER, 88N PTT and ER + PTT loads, imposed by weighted cables from 0° to 100° flexion, in three conditions: intact, PLC injured, and with PLC reconstructed. All specimens were submitted to the three PLC reconstruction techniques, in varying order. Hamstrings tendon autografts (gracilis and semitendinosus) were used in all reconstructions, from each specimen.
Results
Transection of the PLC structures, when compared to the intact state, resulted in statistically significant increases of VR and ER from 0° to 100° flexion ( p < 0.05), but not with isolated PTT loading. The LP technique failed to restore intact VR laxity across 0°−20° flexion ( p < 0.05). When comparing the three techniques, PFLoop and AR were more effective than LP across 50°−100° ( p < 0.05). With ER loading, the three techniques restored intact knee laxity; the PFLoop technique allowed significantly less ER than the native knee from 30° to 100° ( p < 0.05). No difference of PTT was observed between techniques. With combined ER + PTT load, no difference was observed among the three techniques regarding PTT, but LP failed to restore ER at 0° ( p = 0.0471), while PFLoop overconstrained ER across 60°–100° ( p < 0.05).
Conclusion
In this biomechanical study using hamstrings tendons for reconstruction of an isolated PLC injury, the LP technique did not fully restore native knee laxity in extension and initial degrees of knee flexion when VR and ER + PTT loads were applied. The AR and PFLoop techniques caused overconstraint of ER in greater degrees of knee flexion and no significant differences were observed between them.
Level of Evidence
Controlled laboratory study.