Background

Several operative techniques are used by knee surgeons to treat instability of the posterolateral corner of the knee (PLC). The purpose of the present study was to examine the length change pattern of current reconstruction techniques of the PLC and compare them to length change pattern of the corresponding anatomic structures. It was hypothesized, that anatomic reconstructions (according to LaPrade or Frosch) would better mimic length change pattern of the native PLC than isometric reconstructions (according to Arciero, Larson or modified Larson).

Study Design: Controlled laboratory study

Methods

In 8 fresh frozen human cadaveric knees dissection of the lateral collateral ligament (LCL), popliteus tendon (PT) and the popliteofibular ligament (PFL) was performed. Quadriceps muscle was loaded physiologically using cables and hanging weights, according to the muscle fiber orientations and cross-sections, with the knee mounted in a custom-made open chain flexion-extension rig. Pins were inserted at the anatomic insertions of the LCL, PT and PFL and at the insertion of reconstructions techniques according to Larson, Arciero, LaPrade, Bousquet and Frosch. Threads were mounted between these pins. Length change pattern was measured using a rotary encoder across the range of motion from 0 – 120°. Statistical analysis was performed using a 2-way repeated measurements ANOVA with Bonferroni correction.

Results

Length change pattern of the native LCL was mimicked best by the reconstruction of the PLC according to LaPrade (p = n.s. between 0-120° of flexion). Reconstruction of the PLC according to Arciero and Larson led to significantly less lengthening between 40 and 120° of flexion (p < 0.05 each). Modified Larson reconstruction led to less lengthening between 50 and 120° of flexion (p < 0.05). Length change pattern of LCL reconstruction according to Bousquet differed significantly to the native LCL between 10-120° of flexion (p < 0.05). Reconstructions according to Arciero, Larson, modified Larson, LaPrade and Frosch were all able to restore length change pattern of the native PT (p = n.s. between 0-120° of flexion each).

Conclusion

Reconstruction of the PLC according to LaPrade best mimicked length change pattern of the native LCL, whereas reconstruction according to Arciero, Larson, modified Larson and Bousquet only partially mimicked length change pattern of the native LCL. Length change pattern of the native PT was restored by all tested reconstruction techniques.