Scarring of the anterior cruciate ligament to the posterior cruciate ligament does not decrease anterior translation

Frequently, a patient undergoing anterior cruciate ligament (ACL) reconstruction 4 to 6 weeks following the acute injury will be noted to have decreased anterior translation during a Lachman and anterior drawer testing at the time of surgery compared with their examination at the time of their acute injury. Orthopedic surgeons frequently attribute this decreased anterior translation to scarring of the ACL to the posterior cruciate ligament (PCL). We undertook a cadaver study to evaluate this. Four cadaveric lower extremity specimens underwent a midline posterior approach to the knee followed by arthrotomy. The ACL then was cut from its origin on the lateral femoral condyle. Following its release, the ACL was sutured tightly to the PCL. Prior to dissection, the specimens underwent baseline KT-1000 knee arthrometer testing. Following the arthrotomy but prior to ACL release, the KT-1000 test was repeated. KT-1000 testing then was performed after ACL release and repeated after suturing the ACL to the PCL. The results revealed no change in KT-1000 testing following arthrotomy. Anterior translation increased an average of 5 mm following release of the ACL and after suturing to the PCL. No specimen showed a significant decrease in anterior translation following suturing of the ACL to the PCL. These results indicate that while decreased anterior translation from the time of injury to the time of reconstruction may occur, this cannot be explained based on scarring of the ACL stump to the PCL.