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Pregnancy Results in Lasting Changes in Knee Joint Laxity
Author(s) -
Chu Stacey R.,
Boyer Elizabeth H.,
Beyn Bruce,
Segal Neil A.
Publication year - 2019
Publication title -
pmandr
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.617
H-Index - 66
eISSN - 1934-1563
pISSN - 1934-1482
DOI - 10.1016/j.pmrj.2018.06.012
Subject(s) - medicine , valgus , pregnancy , coronal plane , ligamentous laxity , knee joint , body mass index , range of motion , orthodontics , physical therapy , surgery , anatomy , genetics , biology
Background Altered joint laxity can contribute to joint dysfunction. Knee joint laxity has been shown to increase during pregnancy, but its long‐term persistence is unknown. Objective To determine whether pregnancy leads to lasting increases in knee joint compliance and laxity that persist longer than 4 months postpartum. Design Prospective cohort study. Setting A motion analysis laboratory at an academic medical center. Participants Fifty healthy women in their first trimester of pregnancy (mean ± SD 29.2 ± 4.3 years old and baseline body mass index 26.0 ± 5.4 kg/m 2 ) were recruited. Intervention End‐range knee laxity and midrange joint compliance were measured during the first trimester and 19 ± 4 weeks postpartum. Anterior‐posterior and varus‐valgus laxity were measured using 3‐dimensional motion tracking while applying forces and moments in each respective plane using the Vermont Knee Laxity Device. Nonlinear models were constructed to assess relations between applied forces and joint translation, comparing early pregnancy with postpartum. Outcomes Multiplanar knee laxity and compliance. Results Peak varus‐valgus (20‐22%; P = .001) and posterior translation (51%; P < .001) of the tibia relative to the femur decreased from baseline, with a concomitant decrease in laxity ( P < .001) and compliance ( P = .039) in the coronal plane and in the posterior direction in primiparous ( P = .009) and multiparous ( P = .014) women. For primiparous women, laxity ( P < .001) and compliance ( P = .009) increased in the anterior direction. Conclusions Pregnancy resulted in a lasting decrease in multiplanar knee laxity and compliance in the varus and posterior directions with an increase in anterior compliance. The effects of these changes in laxity and compliance of the passive stabilizers on knee loading patterns, articular contact stresses, and risk for osteoarthritis and other musculoskeletal disorders will require additional research. Level of Evidence II