Immediate Postoperative Anterior Knee Stability: Double- Versus Triple-Bundle Anterior Cruciate Ligament Reconstructions

PurposeThe purpose of this study was to compare the triple-bundle (TB) anterior cruciate ligament (ACL) reconstruction with the double-bundle (DB) ACL reconstruction in immediate postoperative anterior knee stability.MethodsThis study involved 133 patients who had undergone the anatomic ACL reconstruction with autogenous hamstring tendon unilaterally. Then 83 patients (mean age, 28.8 years) underwent the DB between November 2004 and December 2005, and 50 patients (mean age, 29.6 years) underwent the TB ACL reconstruction between January and December 2006. The 2 femoral tunnels were created in the ideal ACL attachment area, whereas 2 tibial tunnels for the DB and 3 tunnels for the TB were created in the ACL footprint. The 2 doubled tendon grafts were fixed with EndoButton-CL (Smith & Nephew Endoscopy, Andover, MA) on the femur. The grafts were fixed to the tibia using a Double Spike Plate and a screw under the total initial tension of 20 N at 20° of flexion, after meticulous in situ pretensioning using a tensioning boot. Then immediate postoperative anterior knee laxity in response to 89 N of anterior load was measured by one experienced examiner (T.M.) with the KT-2000 Knee Arthrometer (MEDmedtric, San Diego, CA) under general anesthesia at 30° of knee flexion with muscle relaxants.ResultsThe measured anterior laxity was 3.4 ± 1.2 mm in the DB and 2.5 ± 0.7 mm in the TB ACL reconstruction, a statistically significant difference. The side-to-side difference of the laxity was –3.2 ± 1.6 mm in the DB and –4.2 ± 2.0 mm in the TB, again a significant difference.ConclusionsTB ACL reconstruction resulted in better immediate postoperative anterior knee stability than DB ACL reconstruction under 89 N of anterior tibial load (P = .031).Level of EvidenceLevel III, therapeutic retrospective comparative study.