Transverse femoral fixation in anterior cruciate ligament (ACL) reconstruction with hamstrings grafts: an anatomic study about the relationships between the transcondylar device and the posterolateral structures of the knee.

Iatrogenic risks concerning femoral cross pin devices for anterior criciate ligament (ACL) reconstruction using hamstrings grafts have not been evaluated. The aim of the study was to state anatomic relationships between the epicondylar cross pin hole and the posterolateral attachments of the knee, and to settle safe zones and technical improvements for its use. It is a descriptive anatomical study. Dissections were performed and measurements taken on 20 (2x10) fresh frozen cadaveric knees after standard arthroscopic and femoral ACL reconstruction procedure using the Transfix cross pin femoral device (Arthrex, Naples, FL, USA). In group I, femoral tunnel was performed through the tibial tunnel. In group II, an anteromedial portal technique was used. Group I: no iatrogenic injury. The cross pin was at 36.5+/-2.8 mm (33-41) from the femoral inferior articular area, and at 12.3+/-3.2 mm (7-17) from the lateral collateral ligament (LCL) insertion. Group II: in a half cases, there was an injury of the LCL, close to its insertion. The cross pin was at an average of 5.6+/-5.4 mm (0-15) from the LCL, and significantly closer in group II than in group I (P<0.01). In group I, there is a high correlation between cross pin to LCL distance and knee flexion obtained to drill the femoral tunnel (r (2)=0.75, P<0.01). In conclusion, there is a specific iatrogenic risk of transverse femoral fixation using the anteromedial portal approach, whereas the transtibial approach seems to be safe. Nevertheless, it can decrease with a correct femoral tunnel depth and an operative knee flexion over 130 degrees , in order to move LCL insertion and posterior cortical wall away.