title: Extra-articular ACL Reconstruction and Pivot Shift: In Vivo Dynamic Evaluation With Navigation.
abstract: BACKGROUND
  The pivot-shift test is considered a reliable examination to evaluate the results of anterior cruciate ligament (ACL) reconstruction, as it strongly correlates with patient satisfaction, giving-way episodes, and activity level. The addition of lateral tenodesis (LT) to current techniques of intra-articular reconstruction with a hamstring graft could potentially improve knee laxity in cases of severe rotational instability.
  
  
  OBJECTIVE
  To biomechanically investigate the effect of intra- and extra-articular ACL reconstructions on knee laxity and the pivot-shift phenomenon.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Twenty patients underwent anatomic single-bundle ACL reconstruction with doubled semitendinosus and gracilis tendons with the addition of extra-articular reconstruction. In patients in group A, intra-articular reconstruction was performed first and LT thereafter; in patients in group B, LT was performed first and intra-articular reconstruction thereafter. A navigator equipped with software designed for both static and dynamic evaluations was used to measure maximum anterior tibial translation (ATT) and axial tibial rotation (ATR) at 30° of flexion (static evaluation) and during the pivot-shift test (dynamic evaluation). Measurements were performed before reconstruction, after the first procedure, and after the second procedure.
  
  
  RESULTS
  For the static evaluation, in group A, the mean ATT significantly decreased from 14.1 ± 3.7 mm in the preoperative (ACL-deficient) condition to 6.0 ± 1.9 mm after ACL reconstruction and to 5.3 ± 1.6 mm after LT. The mean ATR at 30° of knee flexion significantly decreased from 35.7° ± 4.8° to 28.9° ± 4.1° and to 20.9° ± 4.8°, respectively. In group B, the mean ATT significantly decreased from 13.5 ± 6.5 mm in the preoperative (ACL-deficient) condition to 10.2 ± 3.2 mm after LT and to 4.0 ± 1.6 mm after ACL reconstruction. The mean ATR at 30° of knee flexion significantly decreased from 36.7° ± 4.8° to 26.2° ± 6.2° and to 23.5° ± 4.9°, respectively. For the dynamic evaluation (pivot-shift test), in group A, the mean ATT significantly decreased from 15.0 ± 6.8 mm in the preoperative (ACL-deficient) condition to 9.4 ± 6.4 mm after ACL reconstruction and to 8.5 ± 5.4 mm after LT. The mean ATR significantly decreased from 16.9° ± 4.7° to 11.6° ± 4.1° and to 6.1° ± 2.2°, respectively. In group B, the mean ATT significantly decreased from 12.5 ± 3.3 mm in the preoperative (ACL-deficient) condition to 9.1 ± 5.9 mm after LT and to 8.1 ± 5.4 mm after ACL reconstruction. The mean ATR significantly decreased from 16.0° ± 4.5° to 9.2° ± 4.3° and to 7.5° ± 4.0°, respectively.
  
  
  CONCLUSIONS
  Extra-articular reconstruction had little effect in reducing the anterior displacement of the tibia at 30° of flexion, but it was more effective than intra-articular reconstruction in reducing ATR. Anatomic ACL reconstruction and LT were synergic in controlling the pivot-shift phenomenon.
authors.affiliation: Kirk Kilgour Sports Injury Center, Sant'Andrea Hospital, University of Rome La Sapienza-II School of Medicine, Rome, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Monaco
authors.affiliation: Kirk Kilgour Sports Injury Center, Sant'Andrea Hospital, University of Rome La Sapienza-II School of Medicine, Rome, Italy b.maestri@hotmail.it.
authors.forename: Barbara
authors.initials: B
authors.lastname: Maestri
authors.affiliation: Kirk Kilgour Sports Injury Center, Sant'Andrea Hospital, University of Rome La Sapienza-II School of Medicine, Rome, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Conteduca
authors.affiliation: Kirk Kilgour Sports Injury Center, Sant'Andrea Hospital, University of Rome La Sapienza-II School of Medicine, Rome, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Mazza
authors.affiliation: Kirk Kilgour Sports Injury Center, Sant'Andrea Hospital, University of Rome La Sapienza-II School of Medicine, Rome, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Iorio
authors.affiliation: Kirk Kilgour Sports Injury Center, Sant'Andrea Hospital, University of Rome La Sapienza-II School of Medicine, Rome, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ferretti
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000601:surgery; D007719:Knee Joint / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D053656:Tenodesis / Q000379:methods*; D013977:Tibia / Q000601:surgery
keywords: ACL reconstruction; computer navigation; lateral tenodesis; pivot shift