Anterior tibial translation during eccentric, isokinetic quadriceps work in healthy subjects

The effect of increasing isokinetic, eccentric quadriceps torques on sagitt al translation of the tibia was examined in six healthy volunteers and comp ared to the translation at 20 degrees of knee flexion during a drawer test with 90 N force. The tibial translation increased in a linear fashion with a mean of 0.5 mm per 20% torque increase. In 20 degrees of knee flexion, 10 % of eccentric quadriceps peak torque consumed 80% of the anterior tibial t ranslation induced by the 90 N Lachman test while eccentric quadriceps peak torque utilized 100% of the translation at the same test. The in vivo rela tion between muscle force and tibial translation is of importance in the tr eatment of patients with injury to the cruciate ligaments. The results indi cate that an already low eccentric quadriceps torque causes a tibial transl ation that reaches the limit of the passive knee joint displacement where s train is assumed to develop in the anterior cruciate ligament. Already low eccentric quadriceps torque levels may therefore be harmful during rehabili tation after anterior cruciate ligament surgery.