title: Comparison of Knee Kinematics After Single-Bundle Anterior Cruciate Ligament Reconstruction via the Medial Portal Technique With a Central Femoral Tunnel and an Eccentric Femoral Tunnel and After Anatomic Double-Bundle Reconstruction: A Human Cadaveric Study.
abstract: BACKGROUND
  Anatomic femoral tunnel placement in anterior cruciate ligament (ACL) reconstruction is considered to be a key to good primary stability of the knee. There is still no consensus on whether a centrally placed single bundle in the anatomical femoral footprint can compare with anatomic double-bundle (DB) reconstruction.
  
  
  OBJECTIVE
  The purpose of this study was to determine knee kinematics after single-bundle ACL reconstruction via the medial portal technique using 2 different femoral tunnel positions and to compare results with those of the anatomic DB technique. The hypotheses were that (1) single-bundle reconstruction using the medial portal technique with a centrally placed femoral tunnel relative to the native footprint (SB-central technique) would more closely restore intact knee kinematics compared with the same reconstruction technique with an eccentric femoral tunnel drilled in the anteromedial bundle footprint (SB-AM technique) and (2) DB reconstruction would result in superior kinematics compared with the SB-central technique.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Knee kinematics was examined in 10 fresh-frozen human cadaveric knees using a robotic/universal force-moment sensor system. Kinematics in simulated pivot-shift and 134-N anterior tibial loading tests were determined in different conditions within the same specimen: (1) intact ACL, (2) deficient ACL, (3) SB-AM, (4) SB-central, and (5) DB.
  
  
  RESULTS
  All reconstruction techniques significantly reduced anterior tibial translation (ATT) compared with a deficient ACL at 0°, 15°, 30°, 60°, and 90° in the anterior tibial loading test (P < .01, repeated-measures analysis of variance) and at 0°, 15°, and 30° in the simulated pivot-shift test (P < .001). There were no significant differences in the SB-central group and the DB group compared with the intact ACL. Reconstruction in the SB-AM group resulted in significantly increased ATT compared with the intact ACL in near-to-extension angles in both tests (0°, 15°, and 30°; P < .01). SB-central and DB reconstructions both resulted in significantly reduced ATT, in some tests at ≤30°, compared with SB-AM reconstruction (P < .05). No significant differences between the SB-central and DB groups were found (P > .05).
  
  
  CONCLUSIONS
  The SB-central technique restored intact knee kinematics more closely than did SB-AM reconstruction at time zero. There were no differences in knee kinematics between the DB and SB-central techniques.
  
  
  CONCLUSIONS
  Anatomic single-bundle ACL reconstruction provides similar knee kinematics as anatomic double-bundle reconstruction.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Muenster, Germany mirco.herbort@uni-muenster.de.
authors.forename: Mirco
authors.initials: M
authors.lastname: Herbort
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Muenster, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Domnick
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Muenster, Germany.
authors.forename: Michael Johannes
authors.initials: MJ
authors.lastname: Raschke
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Muenster, Germany.
authors.forename: Simon
authors.initials: S
authors.lastname: Lenschow
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Westphalian Wilhelms University Muenster, Muenster, Germany.
authors.forename: Tim
authors.initials: T
authors.lastname: Förster
authors.affiliation: Sporthopaedicum Straubing, Straubing, Germany.
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
authors.affiliation: Department of Orthopedic and Trauma Surgery, Martin Luther Hospital, Berlin, Germany.
authors.forename: Thore
authors.initials: T
authors.lastname: Zantop
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D005269:Femur / Q000502:physiology / Q000601:surgery*; D006801:Humans; D007719:Knee Joint / Q000502:physiology* / Q000601:surgery*; D008875:Middle Aged; D013977:Tibia / Q000502:physiology / Q000601:surgery
keywords: ACL reconstruction; anatomic double-bundle reconstruction; anatomic single-bundle reconstruction; femoral aimer; medial portal technique; robotics