Abstract
Background: Posterior laxity occurring after posterior cruciate ligament reconstruction with a tibial tunnel could be related to thinning and permanent elongation of the graft as it is cyclically loaded in vivo.
Hypothesis: The orientation and position of the bone block within the tibial tunnel will have a significant effect on thinning and elongation of the graft after cyclic loading.
Study Design: Controlled laboratory study.
Methods: In test series 1 (27 fresh-frozen graft pairs), all bone blocks were positioned flush with the posterior opening of the tibial tunnel; 1 graft was oriented with the bone block facing posteriorly, whereas its pair was tested with the bone block facing anteriorly. In test series 2 (20 graft pairs), all grafts were oriented with the bone block facing posteriorly; 1 graft had the bone block positioned flush with the posterior tunnel opening, whereas its pair was tested with the bone block recessed 1 cm from the posterior opening.
Results: In series 1, 3 of 27 grafts with posterior bone block orientations failed at the tunnel edge before 2000 cycles of testing could be completed; all specimens with anterior bone block placements survived the testing intact. In series 2, 3 of 20 grafts with recessed bone blocks failed at the tunnel edge, whereas all those with flush bone blocks survived.
Conclusions: The best position for the bone block of a bone-patellar tendon-bone graft was flush with the posterior tunnel opening with the bone block facing anteriorly in the tibial tunnel.
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