Summary

Posterior-drawer external-rotation maneuver during ACL reconstruction surgery can improve final results by reducing tibia to its anatomic location.

Abstract

Objectives: In an ACL deficient knee the tibia is internally rotated and anteriorly displaced. This abnormal anterior location of tibia relative to the femur, approximates PCL origin and insertion and causes PCL kinking and laxation. In case of ACL graft fixation in an anteriorly displaced tibia, the desired tibiofemoral stability will not be achieved and a persistent anterior translation and internal location of tibia will ensue. The presence of PCL buckling in the post-surgery MRI is the result of the failed tibiofemoral reduction in ACL surgery.
ACL reconstruction should end up with relocation of anteriorly displaced and internally rotated tibia relative to the femur. The common practice is the tensioning of the graft by forcibly pulling during the final tibial fixation. Pulling and tensioning the graft will bring the posteriorly placed femur anteriorly but at the same time the tibia may move anteriorly, preventing the relocation of the joint. This technique may not correct the internal rotation of the tibia.
We hypothesized that for obtaining optimal results in ACL surgery, tibia should be reduced before final graft fixation. Our proposed maneuver reduces tibia to its anatomic location by exerting posterior and external rotational force. The purpose of this study is to assess the efficacy of this maneuver.

Methods

In a prospective cohort study from Nov 2011 to Sep 2014, 669 patients with isolated ACL reconstruction were enrolled. In the first 224 cases, the ACL grafts were fixed in a standard fashion with traction applied on the graft. In the remaining 445 cases, we used a posterior drawer external force maneuver to reduce the joint prior to final graft fixation. Quadruple hamstring graft were used in all cases. Meniscal repair was performed in 127 cases (18%) and partial meniscectomy 143 cases (21%). Multi-ligament injuries were not enrolled in this study. The mean follow up was 33 months (24 to 46 months). Lysholm, subjective IKDC, Cincinnati, Tegner-Lysholm activity scores and pivot shift test were recorded prior to surgery and at the final follow up. The anterior translation of tibia was measured using KT 1000 and a motorize arthrometer. The level of significance was set at P < .05.

Results

Despite a slightly better results in the final Lysholm, IKDC, Cincinnati and Tegner-Lysholm activity scores there were no significant differences between two groups, but the anterior translation of tibia measured by KT 1000 and a motorized arthrometer was significantly lower in the maneuver-exerted group. The mean KT-1000 arthrometer side-to-side difference was 3.6 mm for the standard group and 1.9 mm for the maneuver group. The mean arthrometer side-to-side difference in 134 N posteroanterior force was 4.1 mm for the standard group and 2.2 mm for the maneuver group. The clinical pivot shift test (0-3) showed significant better results in the maneuver group. There was no significant difference in re-operation rate between two groups.

Conclusion

We concluded that the use of posterior drawer external rotation maneuver during ACL reconstruction surgery can improve final results by reducing tibia to its anatomic location.