TUNNEL POSITION IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

Abstract

Tunnel placement in Anterior Cruciate Ligament (ACL) reconstruction is the single most important variable that a surgeon can control in order to achieve a successful outcome. The femoral tunnel is more critical than the tibial.

Audit tunnel positions after ACL reconstruction in a regional centre.We studied 114 patients undergoing primary isolated ACL reconstruction within a 12-month period. Case notes and radiographs were reviewed retrospectively. Tunnel position was assessed on lateral and AP radiographs of the knee. A review of literature established optimal tunnel position. Measurements of tunnel position were made according to the methods described by Jonsson.

16 surgeons (8 consultants and 8 registrars) performed 57 arthroscopic and 57 open reconstructions, using 24 hamstring and 90 bone-tendon-bone autografts. Femoral tunnel drilling was through the medial arthroscopic portal (24) or the tibial tunnel (90). 85 sets of radiographs were available for review (21 not performed post-operatively, 8 not found)

In the sagittal plane, the femoral tunnel insertion should be within the posterior third along an extended Blumensaat’s line and the tibial tunnel between 41 and 49% along the tibial joint line from anterior to posterior. In the coronal plane, the tibial tunnel should exit between 41% and 49% along the tibial joint line, from medially. Our results showed that 65% of femoral tunnels were outside this position, 23% of the tibial tunnels out in the sagittal plane and 55% out coronally. Of those drilled through the medial portal, only 5% of the femoral tunnels were outside our recommended position.

Clinical Governance demands that guidelines for best practice are established and that audit ensures these standards are met. Anatomical studies give useful data in determining acceptable standards, as demonstrated in our audit. To enable this it is imperative that post-operative radiographic assessment is performed routinely.