Can Anatomic Posterolateral Corner Reconstruction Using a Fibular Tunnel Restore Fibular Footprints of the Posterolateral Complex? A Cadaveric Study.

PURPOSE

This study aimed to (1) quantitatively analyze the fibular footprints of the lateral collateral ligament (LCL) and popliteofibular ligament (PFL) and (2) evaluate whether a fibular tunnel can restore the LCL and PFL fibular footprints simultaneously without modification in anatomic posterolateral corner reconstruction of the knee.

METHODS

In 20 cadaveric knees, anatomic characteristics, such as diameter, location and relationship with anatomic landmarks, of the LCL and PFL footprints were analyzed. Subsequently, a fibular tunnel that connected the LCL and PFL footprint centers was created with 1.5 mm drill bit, and tunnel depth, which is defined as the distance between the tunnel and the nearest cortex, was evaluated. An additional tunnel from the anteroinferior border of the LCL footprint to the posteroinferior border of the PFL footprint was created, and its tunnel depth was evaluated as well and compared with that of the original tunnel.

RESULTS

The LCL footprint was longitudinally ovoid (8.4 ± 1.0 × 13 ± 1.0 mm), and its inferior margin corresponded well with the lateral apex of the fibula (distance, 1.0 ± 0.7 mm). The PFL footprint was round (9.7 ± 1.3 × 9.0 ± 1.1 mm), and its center was very close to the tip of the fibular styloid process (1.2 ± 0.8 mm). The tunnel depth of the original fibular tunnel was 1.8 ± 0.7 mm, and it was very shallow for tunnel reaming. On the contrary, the tunnel depth of the modified fibular tunnel (6.4 ± 1.1 mm) was significantly higher than that of the original tunnel (P < 0.05), and it was relatively safe for tunnel reaming.

CONCLUSIONS

A single fibular tunnel cannot reproduce the LCL and PFL footprint centers simultaneously because the trajectory is too close to the cortex. A modified fibular tunnel, using the margins of the footprints, is recommended to avoid cortical blowout.

CLINICAL RELEVANCE

A modified fibular tunnel that covers only portions of the LCL and PFL footprints, from the anteroinferior LCL footprint to the posteroinferior PFL footprint, is less likely to blow out the lateral fibula than is a similar tunnel using the anatomic footprint centers.