Abstract
The purpose of this study is to describe a novel radiographic sign indicative of vertical
tunnel placement following anterior cruciate ligament (ACL) reconstruction. We reviewed
190 consecutive ACL reconstructions. Operative records, patient charts, arthroscopic
images, and preoperative and postoperative orthogonal plain radiographic images were
reviewed. We made special note of the operative technique. Note was made of tunnel
position and whether the posterior (proximal) aspect of Blumensaat line was violated
on standard lateral knee radiographic images. Of 190 patients, 17 patients did not
have postoperative imaging and were excluded. Of the 173 remaining knees, 163 were
primary ACL reconstructions and 10 were revision ACL reconstructions. We found that
no anatomically placed ACL femoral tunnel violated Blumensaat line. In all revision
cases exhibiting violation of Blumensaat line, a new femoral tunnel was able to be
drilled while completely avoiding the previously placed, nonanatomic ACL femoral tunnel.
The principal findings of our study demonstrate that violation of Blumensaat line
following ACL reconstruction is an indicator of vertical, nonanatomic femoral tunnel
placement. Furthermore, presence of this radiographic sign indicates that an anatomically
placed femoral tunnel may be drilled while completely avoiding the existing femoral
tunnel during cases of revision ACL reconstruction.
Keywords
anterior cruciate ligament - femoral tunnel - radiographs - vertical - knee - anatomic
- Blumensaat line
