Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: An in vitro simulation

doi:10.1016/j.knee.2009.09.010

The Knee

Volume 17, Issue 3, June 2010, Pages 235-241

https://doi.org/10.1016/j.knee.2009.09.010 Get rights and content

Abstract

We hypothesize that application of an unopposed quadriceps force coupled with an impulsive ground reaction force may induce anterior cruciate ligament (ACL) injury. This situation is similar to landing from a jump if only the quadriceps muscle is active; an unlikely but presumably dangerous circumstance. The purpose of this study was to test our hypothesis using in vitro simulation of jump landing. A jump-landing simulator was utilized. Nine cadaveric knees were tested at an initial flexion angle of 20°. Each ACL was instrumented with a differential variable reluctance transducer (DVRT). Quadriceps pre-activation forces (QPFs) ranging from 25 N to 700 N were applied to each knee, followed by an impulsive ground reaction force produced by a carriage-mounted drop weight (7 kg) that impulsively drove the ankle upward. ACL strain was monitored before landing due to application of QPF (pre-activation strain) and at landing due to application of the ground reaction force (landing strain). No ACLs were injured. Pre-activation strains exhibited a positive correlation with QPF (r = 0.674, p < 0.001) while landing strains showed a negative correlation (r = − 0.235, p = 0.032). Total ACL strain (pre-activation + landing strain) showed no correlation with QPF (r = 0.023, p = 0.428). Our findings indicate that elevated QPF increases pre-activation strain but reduces the landing strain and is therefore protective post-landing. Overall, there is a complete lack of correlation between “total” ACL strain and QPF suggesting that the total strain in the ACL is independent of the QPF under the simulated conditions.

Introduction

The human anterior cruciate ligament (ACL) primarily serves as a restraint against anterior tibial translation at low flexion angles. There are an estimated 80,000 to 250,000 cases annually where the stability of the knee is compromised and the ACL fails [1], [2]. Additionally, about 70% of these failures are classified as non-contact [3]. Activities in which non-contact ACL injuries occur include pivoting or side step cutting, decelerating while the knee is in an extended position, or landing from a jump with the latter being the most often cited [4]. No consensus as to the root cause of these injuries exists among researchers in the field [2].

Despite a lack of agreement as to the cause, many risk factors for non-contact ACL injury have been proposed. Among these, sex is the most widely cited with females exhibiting a 4–6 fold greater incidence of ACL injury [1]. In addition to sex, environmental, anatomical, hormonal, and neuromuscular risk factors have also been identified [2].

A frequently cited mechanism of ACL injury is a process in which the quadriceps muscle force is applied at an exceptionally aggressive level to cause severe anterior tibial translation and subsequent ACL injury. An abundance of evidence in the literature supports this plausible theory [5], [6], [7], [8], [9], [10], [11], [12], [13]. The proponents of the theory suggest that a combination of low knee flexion, strong quadriceps muscle contraction, and a posteriorly directed ground reaction force can increase ACL loading and cause injury [6], [8], [10], [12]. A posteriorly directed GRF tends to increase the flexion of the knee post-landing and, for the body to resist excessive flexion of the knee, the quadriceps load has to increase; this additional increase in the quadriceps force is believed to increase the ACL strain and potentially cause injury [12], [24].

Some argue that hamstring co-contraction will resist anterior tibial translation induced by the aggressive quadriceps pull. However, proponents of the quadriceps pull mechanism contend that at low flexion angles (less than 15°), hamstring co-contraction does not significantly reduce anterior tibial translation and is therefore not protective of the ACL [9], [14].

To address this controversy, we posed the question, “Can an unopposed quadriceps force (without the aid of the hamstring muscle), at a knee flexion angle of 20^o, increase ACL strain to injurious levels when assisted by an impulsive GRF (encountered at landing) during a simulated jump-landing task?” In vivo study of the strain in the ACL during non-impulsive activities has been reported in the literature [9]. However, such measurements during more aggressive and dynamic activities are very rare and controversial. The only other feasible approach to understand ACL loading would be through descriptive laboratory studies by performing simulations of highly dynamic/impulsive activities, invitro. Thus, we tested our hypotheses through in vitro simulation of the vertical jump-landing process in a dynamic loading simulator. We postulate that as the unopposed quadriceps pre-activation force is increased during simulated jump landing (when an impulsive ground reaction force is superimposed), 1) the strain in the ACL would also increase (both prior to and during the landing phase of a jump) and 2) this would lead to ACL injury.

Section snippets

Methods

This was a descriptive laboratory study design intended to assess the effect of quadriceps pre-activation force (QPF) on ACL strain both prior to landing (under the anticipatory application of muscle forces), and during landing (during the application of impulsive forces). We also aimed to assess the overall effect of QPF throughout the landing process in vitro. To this end, cadaveric knees were installed in a dynamic loading simulator and muscle forces were applied, followed by an impulsive

Analysis

Correlation analyses were performed to test the extent of a linear relationship between QPF and ACL strain in each knee. These tests were conducted for ACL strain before simulated landing (pre-activation strain) and ACL strain during the application of the impulsive force (landing strain). In each knee, the pre-activation and landing strains corresponding to each QPF were added to find the total strain in the ACL under the given QPF. A correlation analysis was also performed to assess the

Results

None of the ACLs were injured after simulated jump landing with an unopposed quadriceps force at any tested QPF level. In all nine knees, there was a positive correlation between QPF and ACL pre-activation strain as presented in Table 1. Seven knees showed statistically significant correlations. The correlation for the pooled results of all knees was also found to be significant and positive (Fig. 2).

A negative correlation between QPF and ACL landing strain was found in seven out of nine knees

Discussion

The strain in the ACL during the quadriceps pre-activation stage, presumably occurring in anticipation of landing, produces what we call the pre-activation strain. There are no reports of the level of QPF during landing from a jump. As a result, we used a maximum quadriceps pre-activation of 700 N, approximately the weight of a 70 kg subject. Our results show that unopposed pre-activation of the quadriceps prior to landing will increase pre-activation strain in the ACL. This is supported by an in

Conclusion

Our in vitro simulation results show that even an unopposed quadriceps force aided by an impulsive ground reaction force cannot cause ACL injury during the landing phase of the jump-landing activity when the initial flexion angle is around 20°. There are various means of protection against such a mechanism of injury including pressure-induced joint conformity, hamstring co-contraction, and an anteriorly tilted tibial plateau, all of which will reduce relative movement between the femur and the

Conflicts of Interest

None of the authors report any conflict of interest.

References (25)

B.C. Fleming et al.
The effect of weightbearing and external loading on anterior cruciate ligament strain
J Biomech
(2001)
G. Li et al.
The importance of quadriceps and hamstring muscle loading on knee kinematics and in-situ forces in the ACL
J Biomech
(1999)
T.J. Withrow et al.
The effect of an impulsive knee valgus moment on in vitro relative ACL strain during a simulated jump landing
Clin Biomech
(2006)
B.C. Fleming et al.
The gastrocnemius muscle is an antagonist of the anterior cruciate ligament
J Orthop Res
(Nov 2001)
E. Arendt et al.
Knee injury patterns among men and women in collegiate basketball and soccer: NCAA data and review of literature
Am J Sports Med
(1995)
L.Y. Griffin et al.
Understanding and preventing noncontact anterior cruciate ligament injuries: a review of the hunt valley II meeting, January 2005
Am J Sports Med
(2006)
P.J. McNair et al.
Important features associated with acute anterior cruciate ligament injury
NZ Med J
(1990)
Y. Shimokochi et al.
Mechanisms of non-contact anterior cruciate ligament injury
J Athl Train
(2008)
S.W. Arms et al.
The biomechanics of anterior cruciate ligament rehabilitation and reconstruction
Am J Sports Med
(1984)
L.F. Draganich et al.
An in vitro study of anterior cruciate ligament strain induced by quadriceps and hamstring forces
J Orthop Res
(1990)

G.S. Berns et al.

Strain in the anteromedial bundle of the anterior cruciate ligament under combination loading

J Orthop Res

(1992)

L. Durselen et al.

The influence of muscle forces and external loads on cruciate ligament strain

Am J Sports Med

(1995)

Cited by (48)

Dynamic knee joint stiffness during bilateral lower extremity landing 6 months after ACL reconstruction
2023, Knee
Anterior cruciate ligament (ACL) reconstructions are associated with long-term functional impairments. Improved understanding of dynamic knee joint stiffness and work may provide insights to help address these poor outcomes. Defining the relationship between knee stiffness, work and quadriceps muscle symmetry may reveal therapeutic targets. The purposes of this study were to investigate between-limb differences in knee stiffness and work during early phase landing 6-months after an ACL reconstruction. Additionally, we investigated relationships among symmetry of knee joint stiffness and work during early-phase landing and quadriceps muscle performance symmetry.
Twenty-nine participants (17 M, 20.0 $\pm$ 5.3 years) were tested 6-months after ACL reconstruction. Motion capture analysis was used to assess between-limb differences in knee stiffness and work during the first 60 ms of a double-limb landing. Quadriceps peak strength and rate of torque development (RTD) were assessed with isometric dynamometry. Paired t-tests and Pearson’s product moment correlations were used to determine between-limb differences of knee mechanics and correlations of symmetry respectively.
Knee joint stiffness and work were significantly reduced (p < 0.01, p < 0.01) in the surgical limb (0.021 ± 0.01 Nm*(deg*kg*m)⁻¹, −0.085 ± 0.06 J*(kg*m) ⁻¹) compared to the uninvolved limb (0.045 ± 0.01 Nm*(deg*kg*m)⁻¹, −0.256 ± 0.10 J*(kg*m) ⁻¹). Greater knee stiffness (51 ± 22%) and work (35 ± 21%) symmetry were significantly associated with greater RTD symmetry (44.5 ± 19.4%) (r = 0.43, p = 0.02; r = 0.45, p = 0.01) but not peak torque symmetry (62.9 ± 16.1%) (r = 0.32, p = 0.10; r = 0.34, p = 0.10).
Dynamic stiffness and energy absorption are lower in the surgical knee during landing from a jump. Therapeutic interventions that target increasing quadriceps RTD may help optimize dynamic stability and energy absorption during landing.
Avulsion Fracture of Bicruciate Ligament and Patellar Tendon in Bicruciate-Retaining Total Knee Arthroplasty
2022, Arthroplasty Today
Citation Excerpt :
Measures to alleviate sarcopenia and quadricep muscle strengthening may potentially lessen the risks of similar fracture and enhance the recovery of BCR-TKA patients. Conceptually, this is not unlike a post-ACL reconstruction (ACLR) knee where, although the knee joint has been stabilized and protected by passive restraints (ligaments), active training of dynamic restraints (quadriceps and hamstring muscles) is necessary to minimize the likelihood of a subsequent ACL graft injury [8–13]. In the post-BCR-TKA knee, although both the ACL and PCL (passive restraints) are stable, additional quadriceps and hamstring muscles (active restraint) should be strengthened to protect the ACL, PCL, and their bony attachments [8,10–13].
Tibial intercondylar fracture with anterior cruciate ligament avulsion is a unique but rare complication of bicruciate-retaining total knee arthroplasty. Here, we describe an even rarer condition that the tibial intercondylar fracture involved bicruciate ligament and partial patellar tendon avulsion fracture resulting in significant clinical instability in a 70-year-old woman, a combination not yet reported in the literature. Dual-energy computed tomography helped characterize the fracture. During revision surgery, the bicruciate retaining total knee arthroplasty was revised to posterior-stabilized total knee arthroplasty and the patellar tendon was repaired with a suture anchor. She recovered well progressively, and at 6 months, she could walk with the use of an assisted walking device.
Altered mechanics and increased loading on intact limbs of individuals with a unilateral transtibial amputation in comparison with non-amputees during a start-stop task
2022, Journal of Biomechanics
Individuals with a unilateral transtibial amputation (ITTA) often experience greater loading on the intact limb during running and stepping tasks compared to individuals without amputation. This study aimed to investigate the mechanics of load absorption in the intact limb of ITTA and determine if increased ground reaction forces (GRF) persist during a start-stop task which (i) controlled touch-down velocity and (ii) removed the requirement for on-going locomotion. Data were collected using a twelve-camera motion capture system with two Kistler force platforms. Variables were extracted during the final loading phase of a 2-step start-stop task. The intact limb of ITTA and the dominant limb of able-bodied controls were compared using independent t-tests and effect size analysis. ITTA showed lower knee flexion angles at touchdown (p = 0.007, g = −1.43), and peak vertical GRF (p = 0.01, g = −1.33) compared to control subjects. ITTA also exhibited less hip (p = 0.14, g = 0.76) and ankle (p = 0.002, g = 1.82) absorptive power at touchdown and at peak vertical GRF (hip: p = 0.01, g = 1.23; ankle: p = 0.05, g = 0.97). ITTA exhibited greater peak vertical GRF (p = 0.01, g = 1.30) and braking GRF (p = 0.05, g = −0.96) on the intact limb compared to the controls. Our results indicate altered joint mechanics through the intact limb of ITTA are independent of the touchdown conditions or the need for ongoing locomotion. These altered joint mechanics increased loading experienced by the intact limb. Further work should be conducted examining a variety of other dynamic movements to fully understand the involved mechanics, so that intervention studies can be developed to reduce the load experienced by ITTA.
Mechanics of cadaveric anterior cruciate ligament reconstructions during simulated jump landing tasks: Lessons learned from a pilot investigation
2021, Clinical Biomechanics
Around half of anterior cruciate ligament (ACL) injuries are treated through reconstruction, but the literature lacks mechanical investigation of reconstructions in a dynamic athletic task and rupture environment. The current objective was to ascertain the feasibility of investigating ACL reconstructions in a rupture environment during simulated landing tasks in a validated mechanical impact simulator.
Four cadaveric lower extremities were subjected to simulated landing in a mechanical impact simulator. External joint loads that mimicked magnitudes recorded from an in vivo population were applied to each joint in a stepwise manner. Simulations were repeated until ACL failure was achieved. Repeated measures design was used to test each specimen in the native ACL and hamstrings, quadriceps, and patellar tendon reconstructed states.
ACL injuries were generated in 100% of specimens. Graft substance damage occurred in 58% of ACLRs, and in 75% of bone tendon bone grafts. Bone tendon bone and quadriceps grafts survived greater simulated loading than hamstrings grafts, but smaller simulated loading than the native ACL. Median peak strain prior to failure was 20.3% (11.6, 24.5) for the native ACL and 17.4% (9.5, 23.3) across all graft types.
The simulator was a viable construct for mechanical examination of ACLR grafts in rupture environments. Post-surgery, ACL reconstruction complexes are weaker than the native ACL when subjected to equivalent loading. Bone tendon bone grafts most closely resembled the native ligament and provided the most consistently relevant rupture results. This model advocated reconstruction graft capacity to sustain forces generated from immediate gait and weightbearing during rehabilitation from an ACL injury.
Simulated hip abductor strengthening reduces peak joint contact forces in patients with total hip arthroplasty
2019, Journal of Biomechanics
Citation Excerpt :
While this work simulated the effects of muscle strengthening on joint loading, similar observations have been reported in in-vitro studies. Using servo-hydraulic dynamic testing simulators, in-vitro studies have recreated the reaction forces and muscle loads experienced at the knee during high-demand tasks, such as kneeling and landing (Abo-Alhol et al., 2014; Hashemi et al., 2010; Shalhoub and Maletsky, 2014). By simulating kinematics and applied loads during landing with cadaveric knees, while increasing quadriceps force over a physiological possible range, Hashemi et al. (2010) demonstrated a redirection of ground reaction forces and reductions in ACL strain.
Lower extremity muscle strength training is a focus of rehabilitation following total hip arthroplasty (THA). Strength of the hip abductor muscle group is a predictor of overall function following THA. The purpose of this study was to investigate the effects of hip abductor strengthening following rehabilitation on joint contact forces (JCFs) in the lower extremity and low back during a high demand step down task. Five THA patients performed lower extremity maximum isometric strength tests and a stair descent task. Patient-specific musculoskeletal models were created in OpenSim and maximum isometric strength parameters were scaled to reproduce measured pre-operative joint torques. A pre-operative forward dynamic simulation of each patient performing the stair descent was constructed using their corresponding patient-specific model to predict JCFs at the ankle, knee, hip, and low back. The hip abductor muscles were strengthened with clinically supported increases (0–30%) above pre-operative values in a probabilistic framework to predict the effects on peak JCFs (99% confidence bounds). Simulated hip abductor strengthening resulted in lower peak JCFs relative to pre-operative for all five patients at the hip (18.9–23.8 ± 16.5%) and knee (20.5–23.8 ± 11.2%). Four of the five patients had reductions at the ankle (7.1–8.5 ± 11.3%) and low back (3.5–7.0 ± 5.3%) with one patient demonstrating no change. The reduction in JCF at the hip joint and at joints other than the hip with hip abductor strengthening demonstrates the dynamic and mechanical interdependencies of the knee, hip and spine that can be targeted in early THA rehabilitation to improve overall patient function.
Novel mechanical impact simulator designed to generate clinically relevant anterior cruciate ligament ruptures
2017, Clinical Biomechanics
Citation Excerpt :
Bates et al., 2015a) However, these particular simulators failed to consistently reproduce ACL tears within their cadaveric specimens.( Hashemi et al., 2010; Oh et al., 2011; Oh et al., 2012a; Oh et al., 2012b; Withrow et al., 2006a, 2006b) A drop-stand mechanical impactor developed by our group was the first impulse simulator to successfully and reliably induce ACL failure on cadaveric specimens (Kiapour et al., 2012; Levine et al., 2013; Quatman et al., 2014).
Over 250,000 anterior cruciate ligament ruptures occur each year; therefore, it is important to understand the underlying mechanisms of these injuries. The objective of the current investigation was to develop and analyze an impact test device that consistently produces anterior cruciate ligament failure in a clinically relevant manner.
A mechanical impact simulator was developed to simulate the ground reaction force impulse generated from landing in a physiologic and clinically relevant manner. External knee abduction moment, anterior shear, and internal tibial rotation loads were applied to the specimen via pneumatic actuators. The magnitudes of applied loads were determined in vivo from a cohort of healthy athletes. Loads were systematically increased until specimen failure was induced. Three cadaveric lower extremity specimens were tested and clinically assessed for failure. Knee specimens were physically and arthroscopically examined at baseline and at post-injury by a board certified orthopedic surgeon.
All three specimens experienced failure at either the midsubstance or the femoral insertion site. The mean peak strain prior to failure was 18.8 (6.2)%, while the mean peak medial collateral ligament strain was 7.9 (5.9)%.
A board certified orthopedic surgeon confirmed observed rupture patterns were representative of clinical cases. Peak strains were consistent with literature. The novel mechanical impact simulator will allow researchers to assess clinically relevant patterns of rupture and the data generated will inform clinician decisions. This novel machine presents the ability to assess healthy specimens as well as differences in the function of deficient and reconstructed knees.

View all citing articles on Scopus

View full text

Increasing pre-activation of the quadriceps muscle protects the anterior cruciate ligament during the landing phase of a jump: An in vitro simulation

Abstract

Introduction

Section snippets

Methods

Analysis

Results

Discussion

Conclusion

Conflicts of Interest

J Biomech

J Biomech

Clin Biomech

J Orthop Res

Knee injury patterns among men and women in collegiate basketball and soccer: NCAA data and review of literature

Am J Sports Med

Understanding and preventing noncontact anterior cruciate ligament injuries: a review of the hunt valley II meeting, January 2005

Am J Sports Med

Important features associated with acute anterior cruciate ligament injury

NZ Med J

Mechanisms of non-contact anterior cruciate ligament injury

J Athl Train

The biomechanics of anterior cruciate ligament rehabilitation and reconstruction

Am J Sports Med

An in vitro study of anterior cruciate ligament strain induced by quadriceps and hamstring forces

J Orthop Res

Strain in the anteromedial bundle of the anterior cruciate ligament under combination loading

J Orthop Res

The influence of muscle forces and external loads on cruciate ligament strain

Am J Sports Med