In Vivo Anterolateral Ligament Length Change in the Healthy Knee During Functional Activities-A Combined Magnetic Resonance and Dual Fluoroscopic Imaging Analysis.
OBJECTIVE
To measure the in vivo anterolateral ligament (ALL) length change in healthy knees during step-up and sit-to-stand motions.


METHODS
Eighteen healthy knees were imaged using magnetic resonance and dual fluoroscopic imaging techniques during a step-up and sit-to-stand motion. The ALL length change was measured using the shortest three-dimensional wrapping path, with its femoral attachment located slightly anterior-distal (ALL-Claes) or posterior-proximal (ALL-Kennedy) to the fibular collateral ligament attachment. The ALL length measured from the extended knee position of the non-weight-bearing magnetic resonance scan was used as a reference to normalize the length change.


RESULTS
During the step-up motion (approximately 55° flexion to full extension), both the ALL-Claes and ALL-Kennedy showed a significant decrease in length of 21.2% (95% confidence interval 18.0-24.4, P < .001) and 24.3% (20.6-28.1, P < .001), respectively. During the sit-to-stand motion (approximately 90° flexion to full extension), both the ALL-Claes and ALL-Kennedy showed a consistent, significant decrease in length of 35.2% (28.8-42.2, P < .001) and 39.2% (32.4-46.0, P < .001), respectively. From approximately 90° to 70° of flexion, a decrease in length of approximately 6% was seen; 70° of flexion to full extension resulted in an approximately 30% decrease in length.


CONCLUSIONS
The ALL was found to be a nonisometric structure during the step-up and sit-to-stand motion. The length of the ALL was approximately 35% longer at approximately 90° of knee flexion when compared with full extension and showed decreasing length at lower flexion angles. Similar ALL length change patterns were found with its femoral attachment located slightly anterior-distal or posterior-proximal to the fibular collateral ligament attachment.


CONCLUSIONS
These data suggest that, if performing anatomic ALL reconstruction, graft fixation may be performed beyond 70° flexion to reduce the chance of lateral compartment overconstraint. Anatomic ALL reconstruction may affect the knee kinematics more in high flexion than at low flexion angles.
Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.
Willem A
WA
Kernkamp
Focus Clinic Orthopedic Surgery, Medical Center Haaglanden and Bronovo-Nebo, The Hague, The Netherlands.
Samuel K
SK
Van de Velde
Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.
Ali
A
Hosseini
Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.
Tsung-Yuan
TY
Tsai
Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.
Jing-Sheng
JS
Li
Focus Clinic Orthopedic Surgery, Medical Center Haaglanden and Bronovo-Nebo, The Hague, The Netherlands.
Ewoud R A
ERA
van Arkel
Bioengineering Laboratory, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, U.S.A.. Electronic address: Gli1@mgh.harvard.edu.
Guoan
G
Li
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D016059:Range of Motion, Articular; D012016:Reference Values
Knee. 2006 Jan;13(1):77-82
16463439
Am J Sports Med. 2009 Mar;37(3):534-41
19088056
Am J Sports Med. 2011 Jan;39(1):199-217
20709943
Am J Sports Med. 2016 Oct;44(10 ):2557-2562
27338618
Orthop Traumatol Surg Res. 2015 Sep;101(5):523-8
26183087
Am J Sports Med. 2006 Aug;34(8):1240-6
16636348
Arthroscopy. 2007 Mar;23(3):269-74
17349469
Bone Joint J. 2014 Mar;96-B(3):325-31
24589786
Orthop J Sports Med. 2015 Dec 16;3(12):2325967115621024
26779553
Am J Sports Med. 2015 Jul;43(7):1606-15
25888590
J Bone Joint Surg Am. 1976 Mar;58(2):173-9
1254620
Am J Sports Med. 2015 Jul;43(7):1598-605
25740835
Am J Sports Med. 2016 Mar;44(3):593-601
26831632
Am J Sports Med. 2015 Oct;43(10 ):2545-52
26264771
J Biomech Eng. 2004 Apr;126(2):314-8
15179865
Am J Sports Med. 2015 Feb;43(2):354-62
25540293
Am J Sports Med. 2007 Feb;35(2):294-300
17092925
Orthop J Sports Med. 2014 Dec 17;2(12):2325967114562205
26535292
Acta Orthop Scand. 2004 Oct;75(5):594-9
15513493
Am J Sports Med. 2006 Dec;34(12 ):2026-37
17092921
Am J Sports Med. 2014 Jul;42(7):1669-74
24799424
Knee. 2016 Jan;23 (1):8-12
26749203
Am J Sports Med. 1988 May-Jun;16(3):238-43
3381980
J Anat. 2013 Oct;223(4):321-8
23906341
Am J Sports Med. 2004 Sep;32(6):1415-20
15310565
Am J Sports Med. 2004 Jun;32(4):975-83
15150046
Arthroscopy. 2016 Oct;32(10 ):2017-2024
27157662
Am J Sports Med. 1993 Jan-Feb;21(1):55-60
8427369
Arthroscopy. 2016 May;32(5):835-41
26725451
Arthroscopy. 2016 May;32(5):844-8
26868424
J Bone Joint Surg Am. 2009 Feb;91 Suppl 1:108-14
19182035
J Biomech. 2008;41(7):1616-22
18394629