Kinematics of Double-bundle and Single-Bundle ACL reconstruction in the MCL-deficient knee
1
Hwang, SC, 1Asai, S, 1 Chen Lianxu, 2 Kramer, S, 1Linde-Rosen, M, 1,2 Smolinski, P, 1,2 Fu, FH
1
Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, USA
2
Department of Mechanical Engineering and Material Science, University of Pittsburgh, Pittsburgh, USA
[email protected]
INTRODUCTION:
The purpose of this study was to evaluate the effect of single-bundle
(SB) and anatomic double-bundle (DB) ACL reconstruction on the
resulting knee kinematics in a simulated clinical setting with ACL
rupture and associated extra-articular damage to the medial structures1,2.
It was hypothesized that anatomic DB ACL reconstruction will better
restore the intact knee kinematics in the MCL-deficient knees than SB
ACL reconstruction.
RESULTS:
Under a simulated KT 1000 test, anterior tibial translation (ATT)
following SB ACL reconstruction was statistically significant at 00, 300,
and 600 of knee flexion when compared to the intact knee. ATT after DB
ACL reconstruction showed no statistically significant difference from
the intact knee; however, there was a significant difference in SB
METHODS:
Ten fresh-frozen porcine cadaver knees were subjected to an anterior
tibial load of 89 N (simulated KT 1000) and a combined rotary load of 7
N-m valgus and 4 N-m internal tibial torque (simulated pivot shift) using
reconstruction at 00 and 300 of knee flexion(Fig 4). Under a simulated
pivot shift test, both SB and DB ACL reconstruction failed to restore the
intact knee kinematics(Fig 5).
a robotic/UFS testing system3,4(Fig 1). Prior to the test, muscle at the
medial knee were divided to exposure the medial capsule and medial
collateral ligament(Fig 2). The resulting knee kinematics was
determined for intact, MCL-deficient, ACL/MCL-deficient, SB ACLreconstructed/MCL-deficient(N=5), and DB ACL-reconstructed/MCLdeficient knee(N=5). The resulting knee kinematics during the external
loads were measured. The testing protocol is given in Fig 3. Statistical
Fig 4 Anterior translation under simulated KT-1000 test. Asterisk
analysis was performed using a two-way ANOVA test with the level of
statistical significance.(P<0.05)
significance set at P<0.05.
Fig 1 Medial collateral ligament of the knee
Fig 2 Porcine knee on the robotic/ UFS testing system
Fig 5 Anterior translation under simulated pivot shift test. Asterisk
statistical significance.(P<0.05)
DISCUSSION:
The result of this study did not support the initial hypothesis. Though
DB reconstruction were superior to SB reconstruction under simulated
KT 1000 test, SB as well as DB reconstruction failed to restore the intact
kinematics under simulated pivot shift loads2,3,4. The clinical relevance
of this study is that caution and precise preoperative diagnosis are
needed to avoid failure of intra-articular ACL reconstruction if the extraarticular stabilizer is torn. A limitation of this study is the number of
specimens tested.
Knee conditions
Kinematics
I.Intact knee
Intact knee kinematics
II.Transection the MCL
III.Transection of the ACL
ACKNOWLEDGEMENT:
MCL–deficient knee kinematics
MCL/ACL-deficient knee
kinematics
IV.SB ACL reconstruction
SB ACL-reconstructed /MCLdeficient knee kinematics in the
SB reconstructed knee
V.DB ACL reconstruction
DB ACL-reconstructed /MCLdeficient knee kinematics in the
DB reconstructed knee
Fig 3 Testing protocol and data obtained
No potential conflict of interesting declared .
REFERENCE:
1. Zantop T, et al. Arch Orthop Trauma Surg. 2010.
2. Amis A, Bull AMJ, Lie DT. Oper Tech Orthop. 2005.
3. Cha PS, Brucker PU, West RV, Fu FH. Arthroscopy. 2005.
4. Gabriel MT, Wong EK, Woo SL et al. J Orthop Res. 2004.
Poster No. 895 • ORS 2011 Annual Meeting