title: Differences in kinematics of single leg squatting between anterior cruciate ligament-injured patients and healthy controls.
abstract: Seventy to eighty percent of all anterior cruciate ligament (ACL) injuries are due to non-contact injury mechanisms. It has been reported that the majority of injuries due to single leg landing come from valgus positioning of the lower leg. Preventing valgus positioning during single leg landing is expected to help reduce the number of ACL injuries. We found that many ACL-deficient patients cannot perform stable single leg squatting. Therefore, we performed 3D motion analysis of the single-legged half squat for ACL-injured patients to evaluate its significance as a risk factor for ACL injuries. We evaluated the relative angles between the body, thigh, and lower leg using an electromagnetic device during single leg half squatting performed by 63 ACL-injured patients (32 males, 31 females) the day before ACL reconstruction and by 26 healthy control subjects with no knee problems. The uninjured leg of ACL-injured male subjects demonstrated significantly less external knee rotation than that of the dominant leg of the male control. The uninjured leg of ACL-injured female subjects demonstrated significantly more external hip rotation and knee flexion and less hip flexion than that of the dominant leg of the female control. Comparing injured and uninjured legs, the injured leg of male subjects demonstrated significantly less external knee and hip rotation, less knee flexion, and more knee varus than that of the uninjured leg of male subjects. The injured leg of female subjects demonstrated more knee varus than that of the uninjured leg of female subjects. Regarding gender differences, female subjects demonstrated significantly more external hip rotation and knee valgus than male subjects did in both the injured and uninjured legs (P < 0.05). The current kinematic study exhibited biomechanical characteristics of female ACL-injured subjects compared with that of control groups. Kinematic correction during single leg half squat would reduce ACL reinjury in female ACL-injured subjects.
authors.affiliation: Section of Orthopedic Surgery, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo 113-8519, Japan. yamazaki.orj@tmd.ac.jp
authors.forename: J
authors.initials: J
authors.lastname: Yamazaki
authors.forename: T
authors.initials: T
authors.lastname: Muneta
authors.forename: Y J
authors.initials: YJ
authors.lastname: Ju
authors.forename: I
authors.initials: I
authors.lastname: Sekiya
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries; D001696:Biomechanical Phenomena; D016022:Case-Control Studies; D005080:Exercise Test; D005260:Female; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D012737:Sex Factors; D013647:Task Performance and Analysis; D055815:Young Adult
references.citation: Am J Sports Med. 1993 Mar-Apr;21(2):231-7
references.pmid: 8465918
references.citation: Am J Sports Med. 2008 Apr;36(4):733-40
references.pmid: 18212346
references.citation: J Biomech. 2001 Oct;34(10):1257-67
references.pmid: 11522305
references.citation: J Strength Cond Res. 2007 Feb;21(1):105-11
references.pmid: 17313276
references.citation: Am J Sports Med. 2008 Jun;36(6):1081-6
references.pmid: 18359820
references.citation: Am J Sports Med. 2003 May-Jun;31(3):449-56
references.pmid: 12750142
references.citation: Am J Sports Med. 2006 Feb;34(2):299-311
references.pmid: 16423913
references.citation: J Orthop Sports Phys Ther. 2005 May;35(5):292-9
references.pmid: 15966540
references.citation: J Athl Train. 2005 Mar;40(1):9-14
references.pmid: 15902318
references.citation: Med Sci Sports Exerc. 2005 Jun;37(6):1003-12; discussion 1013
references.pmid: 15947726
references.citation: J Am Acad Orthop Surg. 2000 May-Jun;8(3):141-50
references.pmid: 10874221
references.citation: J Athl Train. 1999 Apr;34(2):150-4
references.pmid: 16558558
references.citation: N Z Med J. 1990 Nov 14;103(901):537-9
references.pmid: 2243642
references.citation: J Bone Joint Surg Am. 1983 Feb;65(2):154-62
references.pmid: 6687391
references.citation: Am J Sports Med. 2007 Mar;35(3):359-67
references.pmid: 17092928
references.citation: Clin Biomech (Bristol, Avon). 2007 Jul;22(6):681-8
references.pmid: 17499896
references.citation: Am J Sports Med. 2008 May;36(5):971-7
references.pmid: 18272792
references.citation: Orthopedics. 2000 Jun;23(6):573-8
references.pmid: 10875418
references.citation: Am J Sports Med. 2008 Jan;36(1):149-57
references.pmid: 17940142
references.citation: Am J Sports Med. 2005 Apr;33(4):492-501
references.pmid: 15722287
references.citation: J Orthop Res. 1999 Nov;17(6):817-22
references.pmid: 10632447
references.citation: Scand J Med Sci Sports. 2003 Oct;13(5):299-304
references.pmid: 14507295
references.citation: Clin Orthop Relat Res. 2002 Aug;(401):162-9
references.pmid: 12151893
references.citation: J Orthop Res. 1995 Nov;13(6):930-5
references.pmid: 8544031
references.citation: Clin Biomech (Bristol, Avon). 2008 Jul;23(6):806-13
references.pmid: 18395310
references.citation: J Athl Train. 2004 Mar;39(1):17-23
references.pmid: 15085207
references.citation: Clin J Sport Med. 2007 Jul;17(4):263-8
references.pmid: 17620779
references.citation: Am J Sports Med. 1999 Nov-Dec;27(6):699-706
references.pmid: 10569353
references.citation: Am J Sports Med. 1995 Nov-Dec;23(6):694-701
references.pmid: 8600737
references.citation: Am J Sports Med. 2006 Mar;34(3):490-8
references.pmid: 16382007