2015 ISAKOS Biennial Congress Paper #52

Femoral Tunnel Drilling Angles for Posteromedial Corner Reconstructions of the Knee. Computed Tomography Evaluation in a Cadaveric Model

Pablo E. Gelber, MD, PhD, Barcelona SPAIN
Àngel Masferrer-Pino, MD, Barcelona SPAIN
Ferran Abat, MD, PhD, Barcelona, BARCELONA SPAIN
Juan I. Erquicia, MD, Barcelona SPAIN
Xavier Pelfort, PhD, Igualada SPAIN
Joan C. Monllau, MD, PhD, Prof., Barcelona SPAIN

Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Barcelona, SPAIN

FDA Status Not Applicable

Summary: When performing posteromedial reconstructions in combination with PCL, medial collateral and posterior oblique ligaments femoral tunnels should be drilled at 30º axial and coronal angulations. The POL femoral tunnel may also be angled 0º on the coronal plane. Tunnels at 0º axial angulations showed a shorter distance to the intercondylar notch and a higher risk of collision with PCL tunnels.

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Abstract:

Purpose

To determine the best angle to drill the femoral tunnels of the superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL) in concomitant posterior cruciate ligament (PCL) reconstructions to avoid either short tunnels or tunnel collisions

Methods

Eight cadaveric knees were studied. Double bundle PCL femoral tunnels were arthroscopically drilled. sMCL and POL tunnels were performed at 0º and 30º axial and coronal angulations. Specimens were scanned with computed tomography to document the relationships of the sMCL and POL tunnels to the intercondylar notch and PCL tunnels. A minimum tunnel length of 25mm was required.

Results

When an sMCL femoral tunnel was drilled at 0º axial and 30º coronal angulation or 30º axial and 0º coronal angulation, the risk of tunnel collision with the anterolateral bundle tunnel of the PCL increased (p<.001). None POL tunnels collided with either PCL tunnel bundle with the exception of tunnels drilled at 0º axial and 30º coronal angulations, which did so with the AL bundle tunnel of the PCL in 3 out of eight cases (p<.001). The minimum required tunnel length (p<.001 and 0.02 respectively) was obtained in all the sMCL and POL tunnels. However, some of those angled at 0º on the axial plane violated the intercondylar notch.

Conclusions

When performing posteromedial reconstructions in combination with concomitant PCL procedures, sMCL and POL femoral tunnels should be drilled at both 30º axial and coronal angulations. The POL femoral tunnel may also be angled 0º on the coronal plane. Tunnels at 0º axial angulations showed a shorter distance to the intercondylar notch and a higher risk of a collision with PCL tunnels.

CLINICAL RELEVANCE
Specific drilling angles are necessary to avoid short tunnels or collisions between the drilled tunnels when sMCL and POL femoral tunnels are performed with concomitant PCL reconstructions.