Document Title: VanLunen-JAT-Oct03
Article Title: Association of Menstrual-Cycle Hormone Changes with Anterior Cruciate Ligament Laxity Measurements
Authors: Bonnie L Van Lunen, John Roberts, J David Branch, Elizabeth A Dowling.
Publication: Journal of Athletic Training, Dallas, Texas
Date: Oct-Dec 2003.
Volume 38, Issue 4, pages 298-304
Keywords: Female athlete, menstrual cycle, ACL, laxity, arthrometer, radioimmunoassay, estrogen, progesterone

(Figures included. Reference-denoting numbers appear in the same point size as the document text.)

This study examines laxity measured at the female knee (with a MedMetric KT-series arthrometer, which duplicates the manual Lachmann Drawer test) throughout the menstrual cycle, and it provides an excellent overview of previous research. It also gives good insight into the structure of the ACL, and the different types of collagen and their role. (The authors note that because the knee ligaments are alive, their structure is a consequence of the continual remodelling of the tissue in response to conditions. New collagen molecules are continually being synthesized, as old ones are dismantled. Type I collagen imparts greater mechanical strength to connective tissue, whereas type 3 collagen is responsible for tissue elasticity. The authors note that the relative decrease in type I procollagen synthesis with increasing estradiol concentrations may translate into ligament weakening, but as progesterone increases and estrogen is held constant, fibroblast proliferation and type I procollagen synthesis are increased significantly.) Note that this study does not investigate actual ACL-injury rates. The drawback with this type of study is that the amount of force exerted by the KT-series measuring device is unlikely to be enough to distinguish the ACL-weakening effect of the reproductive hormone estrogen. Furthermore, note that simply because estrogen tends to decrease the rupture strength of connective tissues (including knee ligaments such as the ACL) does not automatically guarantee that measurable laxity will be observable at the rather low stressing levels typical of manual Lachmann/anterior-drawer testing. This article should be read in conjunction with the studies by Wojtys (Sep/Oct 1998 and Mar/Apr 2002 issues of the American Journal of Sports Medicine; both articles are here in the Knee Library), given that Wojtys delves penetratingly into the connection between the female menstrual cycle and actual ACL-injury occurrence. Van Lunen et al. also note the ACL-injury incidence in female athletes is influenced by neuromuscular, structural, and biomechanical factors, in addition to the hormonal ones studied. (And, there are other hormones circulating in the body besides the reproductive ones.) They also point out that with regards to testing for knee laxity with the KT-series devices, the examiner (due to right-handedness or left-handedness) is often more comfortable with testing either the right or left limb; this, in turn, can significantly affect the readings. (Also, it is difficult to ensure that a given knee is at exactly the same flexion angle in each text, because the likelihood that a given person will always be lying with exactly the same positioning on the examination table [at examinations that are several weeks apart] is rather low. The tension in the ACL changes throughout the range of motion, and so the laxity measurements will be affected by knee flexion angle.)

Abstract: Van Lunen et al seek to determine whether anterior cruciate ligament (ACL) laxity (as evaluated with the KT-2000 and radiographic measures) is associated with concentrations of reproductive hormones during the menstrual cycle and whether the KT-2000 knee arthrometer is a valid measurement technique, compared with radiographic techniques. After discussing the results, they conclude that there is no association between follicular-, ovulatory-, and luteal-phase hormonal concentrations and ACL laxity as measured on the KT-2000 and radiographs; no effects of menstrual-cycle phase on ACL laxity as measured by the KT-2000 and radiographs; and significant differences between KT-2000 and radiographic measures of ACL laxity.

Objective: To determine whether anterior cruciate ligament (ACL) laxity (as evaluated with the KT-2000 and radiographic measures) is associated with concentrations of reproductive hormones during the menstrual cycle and whether the KT-2000 knee arthrometer is a valid measurement technique, compared with radiographie techniques.

Design and Setting: A within-subjects linear model was used. Venipuncture was conducted in an exercise science laboratory. The KT-2000 and radiographie measurements were performed in a hospital radiology laboratory.

Subjects: Twelve females presented with a dominant right leg free of injury. They were mild to moderately active and had a 12-month history of normal menstrual cycles (28-35 days). Subjects had not used hormonal therapy for the previous 3 months.

Measurements: Subjects were tested at the onset of menses, near ovulation, and on day 23 of the midluteal phase of the menstrual cycle. At each session, 14 ml of blood was obtained by venipuncture. Blood samples were analyzed via radioimmunoassay to determine the relative levels of each hormone. Anterior cruciate ligament laxity was simultaneously measured by KT-2000 and radiographic techniques.

Results: Anterior cruciate ligament laxity measurements were significantly greater with the KT-2000 than with radiographic measurement. No significant differences were noted between menstrual-cycle phase and ACL laxity for either method. The concentration of luteinizing hormone was negatively correlated with laxity at the onset of menses using the radiographic technique.

Conclusions: We found no associations between follicular-, ovulatory-, and luteal-phase hormonal concentrations and ACL laxity as measured on the KT-2000 and radiographs; no effects of menstrual-cycle phase on ACL laxity as measured by the KT-2000 and radiographs; and significant differences between KT-2000 and radiographic measures of ACL laxity.

To access the full text of this article, please click here.
There is no charge for viewing articles. However, a password is required.
If you do not already have a password, please e-mail Michael Frind at frind@execulink.com for one.
Prior to requesting a password, please make certain you have read the Site Terms of Use pertaining to this site.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Copyright National Athletic Trainers Association Oct-Dec 2003. For details regarding copyright as it applies to this page, please visit the page entitled "Site Terms of Use and Aspects of Copyright" on this site.

This website was created for the benefit of the world's largest knee-injury community, Bob's ACL WWWBoard (also known as the Kneeboard), accessible to everyone at http://factotem.org.

Documents posted on this site serve merely as a virtual library, and are intended solely for purposes of making access to high-quality peer-reviewed medical-journal articles convenient for all users of the Kneeboard. Knee-injury patients are hereby encouraged to discuss this material with their respective medical teams.

Site Terms of Use and Aspects of Copyright

Printing Hints and Tips