The "N + 7 rule" for tibial tunnel placement in endoscopic anterior cruciate ligament reconstruction.

Miller, M D; Hinkin, D T · Arthroscopy · 1996

expert_opinion · Level V

Where this comes from

Abstract

Tibial tunnel placement during endoscopic anterior cruciate ligament (ACL) reconstruction has received increased emphasis in the recent literature. Appropriate tunnel length is a critical technical consideration. A tunnel that is too short results in graft extrusion, necessitating supplemental fixation techniques. A tunnel that is too long may make distal fixation and femoral tunnel placement difficult. A simple rule is proposed that allows for correct tunnel length and allows placement of the bone plug consistently within the tibial tunnel, allowing interference screw fixation.

Medical subject headings

Anatomy