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Screening for ACL Injuries

Karl Gilligan
www.kg-elite-performance.ie

Introduction
Injury to the anterior cruciate ligament (ACL) is a common and devastating injury for any player, but particularly for the younger player who is still trying to establish himself within the team. Typical rehabilitation time can be between 6-8 months which has major consequences on both physical and technical development. Conor Murray can count himself lucky that he did not suffer any ACL related injury when landing on a single leg after catching the ball. This may have been due to his strength and conditioning training he has been doing to date, whereby, high risk movement patterns associated with ACL injuries seen when landing from a jump were not as pronounced. Others unfortunately are not so lucky. So what can we do to potentially reduce the incidence rate of such a devastating injury? Short answer, screen for potential risk factors.

Functional Movement Screen (FMS)
A pre-participation examination is often performed annually by physiotherapists working with rugby teams to anticipate and preclude physiological and biomechanical problems for players prior to the commencement of a rugby season. As such, the ultimate goal of such a pre-participation examination is injury prevention. In the traditional sports medicine model, pre-participation examinations are followed by performance fitness assessments. This systematic process doesn’t seem to provide enough baseline information when assessing an individual’s preparedness for activity. Commonly, the medical pre-participation examination includes only information that will exclude an individual from participating in certain activities. More recently, strength and conditioning coaches/physiotherapists have been utilising movement tests as part of the pre-participation exam. An example of these movement tests would be the Functional Movement Screen (FMS) by Gray Cook. The Functional Movement Screen (FMS) is one evaluation tool that attempts to assess the fundamental movement patterns of an individual (Cook, 2001). This assessment tool fills the void between the pre-participation screenings and performance fitness tests by evaluating individuals in a dynamic and functional capacity. It has recently been shown that low scores on the FMS correlate with injury in professional football players, firefighters, and military recruits (Kiesel et al., 2007; Kiesel, Butler, and Plisky, 2009; Raleigh et al., 2010), however, the study was not sensitive to predicting any particular injury. It has also been shown that FMS scores improve and the number of asymmetries decreases following an intervention programme (Kiesel et al., in press). However, no studies to date using the FMS have been able to predict non-contact ACL injuries. It is also questionable whether the tests used and the layout of the FMS scoring system will be able to reliably predict non-contact ACL injuries.

Landing Error Scoring System (LESS)
So if the FMS is unproven in detecting ACL injuries, what can we do? Well there are other screens which are ACL sensitive for injury prediction. The Landing Error Scoring System (LESS) as outlined by Padua et al., (2009), is an inexpensive easy to use screen which identifies potentially high risk movement patterns a player may make when performing a jump manoeuvre.

Players perform 4 trials of a standardized jump-landing task. The task required players to jump forward from a 30-cm-high box, which was set at a distance of 50% of their height away from the target landing area; land in the target landing area; and immediately rebound by jumping to maximal vertical height on landing (Figure 1). During task instruction, emphasis is placed on players starting the jump in a neutral position (ie, feet shoulder width apart and toes pointing forward) and jumping as high as they could after their initial landing from the box. Players are not provided any feedback or coaching on their landing technique.
See below for jump landing test layout.

Date:

Name:

Score:
0 – 1 – Excellent
2 – 3 – Average
4 – 7 – Poor

Front View:

Test No Joint/Variable Compensation Yes/No Left/Right Score
1 Feet Feet turned out / in
2 Feet Asymmetrical foot contact
3 Knee Knee valgus
(knees buckle in)
4 Trunk ↑ Trunk side flexion
Score    /4

Side View:

Test No Joint/Variable Compensation Yes/No Left/Right Score
1 Landing Lands on heels
2 Knee Flexion < 20⁰
3 Trunk Flexion < 20⁰
Score    /3

Should a player score “poor” on this test or score “3” with feet turned out, asymmetrical foot contact and knee valgus, they should be placed on a corrective exercise programme to reduce these movement errors as these three compensations are particularly causative factors for ACL related injuries.

Conclusion
Pre-participation examinations are often performed based on the assumption that they contribute to the identification of risk factors for injury, and therefore, lead to the implementation of appropriate injury prevention strategies for athletes. However, despite evidence identifying some specific risk factors for injury that may be identified in a pre-participation examination, little evidence exists supporting the use of pre-participation examinations to reduce injury rates among rugby players. Identification of previous injury (such as ankle sprains) and providing appropriate prevention strategies (such as balance training) has been shown to reduce the risk of recurrent injury. There is also evidence that some specific pre-participation examination components will identify known risk factors (i.e. specific strength, flexibility, balance tests) which may be addressed in the context of injury prevention strategies for that player. However, much needed research to further validate specific components of the pre-participation exam and provide further evidence for identification of rugby-specific risk factors is needed. The movement compensation screen (MCS) as outlined in this article can help the strength and conditioning coach/physiotherapist in assessing players who may be at risk of ACL related injuries and in doing so reduce long term injury rates amongst their players.