Diagnostic Value of Knee Arthrometry in the Prediction of Anterior Cruciate Ligament Strain During Landing

Abstract

Background Previous studies have indicated that higher knee joint laxity may be indicative of an increased risk of anterior cruciate ligament (ACL) injuries. Despite the frequent clinical use of knee arthrometry in the evaluation of knee laxity, little data exist to correlate instrumented laxity measures and ACL strain during dynamic high-risk activities. Purpose/Hypotheses The purpose of this study was to evaluate the relationships between ACL strain and anterior knee laxity measurements using arthrometry during both a drawer test and simulated bipedal landing (as an identified high-risk injurious task). We hypothesized that a high correlation exists between dynamic ACL strain and passive arthrometry displacement. The secondary hypothesis was that anterior knee laxity quantified by knee arthrometry is a valid predictor of injury risk such that specimens with greater anterior knee laxity would demonstrate increased levels of peak ACL strain during landing. Study Design Controlled laboratory study. Methods Twenty cadaveric lower limbs (mean age, 46 ± 6 years; 10 female and 10 male) were tested using a CompuKT knee arthrometer to measure knee joint laxity. Each specimen was tested under 4 continuous cycles of anterior-posterior shear force (±134 N) applied to the tibial tubercle. To quantify ACL strain, a differential variable reluctance transducer (DVRT) was arthroscopically placed on the ACL (anteromedial bundle), and specimens were retested. Subsequently, bipedal landing from 30 cm was simulated in a subset of 14 specimens (mean age, 45 ± 6 years; 6 female and 8 male) using a novel custom-designed drop stand. Changes in joint laxity and ACL strain under applied anterior shear force were statistically analyzed using paired sample t tests and analysis of variance. Multiple linear regression analyses were conducted to determine the relationship between anterior shear force, anterior tibial translation, and ACL strain. Results During simulated drawer tests, 134 N of applied anterior shear load produced a mean peak anterior tibial translation of 3.1 ± 1.1 mm and a mean peak ACL strain of 4.9% ± 4.3%. Anterior shear load was a significant determinant of anterior tibial translation (P <.0005) and peak ACL strain (P = .04). A significant correlation (r = 0.52, P <.0005) was observed between anterior tibial translation and ACL strain. Cadaveric simulations of landing produced a mean axial impact load of 4070 ± 732 N. Simulated landing significantly increased the mean peak anterior tibial translation to 10.4 ± 3.5 mm and the mean peak ACL strain to 6.8% ± 2.8% (P <.0005) compared with the prelanding condition. Significant correlations were observed between peak ACL strain during simulated landing and anterior tibial translation quantified by knee arthrometry. Conclusion Our first hypothesis is supported by a significant correlation between arthrometry displacement collected during laxity tests and concurrent ACL strain calculated from DVRT measurements. Experimental findings also support our second hypothesis ...

Anatomy and Physiology of Knee Stability

“…As a result, it is the most frequently injured and has been the major focus of studies in recent decades, and its importance and fundamental role in knee stability has led to a substantial body of work investigating its anatomy [16,17], physiology [18,19], biomechanics [20][21][22], assessment [23][24][25][26][27], risks [28,29], and rehabilitation [30][31][32][33][34]. The ACL is supplied by branches of the genicular artery, which consists of two bundles, the anteromedial and posterolateral.…”

The influence of muscle-tendon forces on ACL loading during jump landing: a systematic review

“…Another in vitro cadaveric testing apparatus to simulate jump landing was introduced by Levine et al 27 and used in the same or a subset of eight male and eight female cadaveric specimens to analyse the relationship between AM-ACL strain and multi-planar knee kinematics 28,29 as well as loading conditions and injury patterns at point of ligament failure 27,29 . It should be noted that the exact number of specimens is difficult to extract from the literature because subject-specific characteristics are not always fully detailed, and thus, several studies may have used the same specimens.…”

“…The anatomically-based FE model accurately captured the 3D spatial orientation of the fibres inside the ligaments to analyse the strain in the different bundles. The model was then later validated against in vitro results by the same Authors 29 , and subsequently adopted to better interpret experimental findings on the relationship between multi-planar knee kinematics and ACL loading from cadaveric testing 30 . While the model accurately captured the 3D fibre orientation of the ligaments, the muscle-tendon structures were represented by straight-line segments with their line-of-action taken from the literature.…”

Strain distribution in the anterior cruciate ligament in response to anterior drawer force to the knee

“…The strain in the mid-substance of the human ACL was previously quantified in vivo using a differential variable reactance transducer (DVRT) and found to be 2.00±0.17% during the Lachman test at 140 N of anterior tibial drawer force (Cerulli et al, 2003). A DVRT was also used to measure the strain in the mid-substance of the ACL in vitro and found to be 4.8% when the knee was subjected to a simulated bipedal landing (Kiapour et al, 2014). Thus, the strain in the mid-substance of the ACL has been quantified, but the strain distribution throughout the ACL could not be obtained using a DVRT.…”