Biomechanical measures during landing and postural stability predict second anterior cruciate ligament injury after anterior cruciate ligament reconstruction and return to sport

Abstract

Background: Athletes who return to sport participation after anterior cruciate ligament reconstruction (ACLR) have a higher risk of a second anterior cruciate ligament injury (either reinjury or contralateral injury) compared with non-anterior cruciate ligament-injured athletes.

Hypotheses: Prospective measures of neuromuscular control and postural stability after ACLR will predict relative increased risk for a second anterior cruciate ligament injury.

Study design: Cohort study (prognosis); Level of evidence, 2.

Methods: Fifty-six athletes underwent a prospective biomechanical screening after ACLR using 3-dimensional motion analysis during a drop vertical jump maneuver and postural stability assessment before return to pivoting and cutting sports. After the initial test session, each subject was followed for 12 months for occurrence of a second anterior cruciate ligament injury. Lower extremity joint kinematics, kinetics, and postural stability were assessed and analyzed. Analysis of variance and logistic regression were used to identify predictors of a second anterior cruciate ligament injury.

Results: Thirteen athletes suffered a subsequent second anterior cruciate ligament injury. Transverse plane hip kinetics and frontal plane knee kinematics during landing, sagittal plane knee moments at landing, and deficits in postural stability predicted a second injury in this population (C statistic = 0.94) with excellent sensitivity (0.92) and specificity (0.88). Specific predictive parameters included an increase in total frontal plane (valgus) movement, greater asymmetry in internal knee extensor moment at initial contact, and a deficit in single-leg postural stability of the involved limb, as measured by the Biodex stability system. Hip rotation moment independently predicted second anterior cruciate ligament injury (C = 0.81) with high sensitivity (0.77) and specificity (0.81).

Conclusion: Altered neuromuscular control of the hip and knee during a dynamic landing task and postural stability deficits after ACLR are predictors of a second anterior cruciate ligament injury after an athlete is released to return to sport.

Conflict of interest statement

One or more authors has declared a potential conflict of interest:

Figures

Figure 1

Picture of participant with the identification of the 37 retroreflective marker locations used for 3-dimensional motion analysis.

Figure 2

Diagrammatic skeletal representation of drop vertical jump maneuver used in this study.

Figure 3

Participant during the assessment of postural stability using the Biodex SD Stability System. The individual is in a unilateral stance position with the contralateral limb flexed and both arms crossed at the chest. The participant is tested with eyes open, but receives no visual feedback on performance during the testing session.

Figure 4

The corresponding receiver operating curve (ROC) plotted for the overall model. Multivariable logistic regression identified 4 variables that predicted a second anterior cruciate ligament injury after anterior cruciate ligament reconstruction and return to sports. The area under the ROC statistic is shown with an area under the ROC of 0.94.

Figure 5

Example of second anterior cruciate ligament (ACL) injury predictors in a patient with history of a right ACL injury and reconstruction. A, participants who sustained a second ACL injury had a contralateral hip internal rotation moment during the first 10% of the landing cycle compared with an external rotation moment in the group of patients who did not suffer a second injury. B, participants who sustained a second ACL injury had a side-to-side difference in sagittal plane knee moment at initial contact with a knee extensor moment on the contralateral limb and a knee flexor moment in the involved limb. All moments are described as internal moments.

Figure 6

A, internal hip rotation moment averaged over stance phase for the anterior cruciate ligament (ACL) and second ACL injured groups. B, scatter plot of internal hip rotation moment impulse for ACL (dots) and second ACL (squares) injured groups. Impulse was calculated during the initial 10% of stance.

Figure 7

Example of second anterior cruciate ligament (ACL) injury predictors in a patient with history of a right ACL injury and reconstruction. Participants who sustained a second ACL injury had increased 2-dimensional peak frontal plane knee motion during the landing phase of the drop vertical jump.

Figure 8

Sagittal plane knee moments at initial contact for the involved and uninvolved limb of the initial anterior cruciate ligament (ACL) injury group and the second ACL injury group.