Characterizing the Influence of Preconditioning on Initial Tension for Hamstring Tendon and Patella Tendon Grafts

The primary goal of ACL reconstruction is to limit post-operative anterior knee laxity without over-constraining the knee. For both hamstring tendon and patella tendon grafts used for ACL reconstruction, initial graft tension is applied to limit post-operative knee laxity. Both types of graft stress relax following implantation, decreasing the graft tension. Previous studies have shown that preconditioning reduces the tension decrease due to stress relaxation for both hamstring tendons [1] and patella tendons [2]. While hamstring tendon grafts are typically preconditioned in tension on a graft board prior to implantation to limit stress relaxation, patella tendon grafts are typically implanted without preconditioning. The current study focused on characterizing the influence of preconditioning on stress relaxation for both types of graft. The authors hypothesized that the tension loss due to stress relaxation would be larger for preconditioned hamstring tendon grafts than for preconditioned patella tendon grafts.