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This Article Full Text Full Text (PDF) All Versions of this Article: 35/12/2083    most recent 0363546507308548v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Request Reprints Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Cuomo, P. Articles by Amis, A. A. Search for Related Content PubMed PubMed Citation Articles by Cuomo, P. Articles by Amis, A. A. Related Collections Reconstruction Knee Graft fixation

The Effects of Different Tensioning Strategies on Knee Laxity and Graft Tension After Double-Bundle Anterior Cruciate Ligament Reconstruction

Pierluigi Cuomo, MD^*,,, Krishna Reddi Boddu Siva Rama, MD, Anthony M. J. Bull, PhD and Andrew A. Amis, DSc(Eng)^,||,

From the ^* First Orthopaedic Clinic, University of Florence, Florence, Italy, Department of Mechanical Engineering, Imperial College London, London, United Kingdom, Department of Bioengineering, Imperial College London, London, United Kingdom, and ^|| Department of Musculoskeletal Surgery, Imperial College London, London, United Kingdom

Address correspondence to Andrew A. Amis, Biomechanics Section, Mechanical Engineering Building, Imperial College, London, London SW7 2AZ, UK (e-mail: a.amis{at}imperial.ac.uk).

Background: Double-bundle anterior cruciate ligament reconstruction replicates the 2 functional bundles of the native ligament, the posterolateral and the anteromedial, to control anteroposterior and rotational laxity.

Hypothesis: Double-bundle anterior cruciate ligament reconstruction laxity should be affected by the way grafts are tensioned.

Study Design: Controlled laboratory study.

Methods: Fourteen intact cadaveric knees were instrumented in a 6 degree of freedom rig, and kinematics throughout flexion-extension were recorded with an electromagnetic system under a 90-N anterior force or a 5-N·m internal rotation torque. Anteromedial and posterolateral bundle bovine extensor tendon grafts were fixed to load cells on the tibia, and tension was adjusted to match the intact knee anteroposterior laxity with 3 different protocols: (1) anteromedial bundle first and then posterolateral bundle at 90° and 20° of flexion, respectively; (2) posterolateral bundle first and then anteromedial bundle at 20° and 90° of flexion, respectively; and (3) both bundles together at 20° of flexion. Finally, a single-bundle graft positioned at 10 o’clock was tensioned at 20° of flexion.

Results: Lower graft tensions were required to match intact knee laxity in double-bundle anterior cruciate ligament reconstruction. Tension patterns with knee flexion were independent from the tensioning protocol. Protocols 1 and 2 overconstrained anteroposterior laxity, whereas protocol 3 matched intact knee anteroposterior laxity throughout the range of motion. The single-bundle reconstructions had excess anteroposterior laxity in flexion. Rotations were better restored with double-bundle protocols 2 and 3.

Conclusion: Knee laxity after double-bundle anterior cruciate ligament reconstruction is affected by the sequence in which the grafts are tensioned.

Clinical Relevance: Double-bundle anterior cruciate ligament reconstruction ensures better laxity restoration than does single bundle when both bundles are fixed together.

Key Words: anterior cruciate ligament • anatomic reconstruction • double bundle • graft tensioning