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ANTERIOR CRUCIATE LIGAMENT: A RESEARCH UPDATE ON THE CANCER OF THE KNEE Luke Bahnmaier MS, ATC/L, OTC Idaho Athletic Trainer’s Association Summer Symposium.

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Presentation on theme: "ANTERIOR CRUCIATE LIGAMENT: A RESEARCH UPDATE ON THE CANCER OF THE KNEE Luke Bahnmaier MS, ATC/L, OTC Idaho Athletic Trainer’s Association Summer Symposium."— Presentation transcript:

1 ANTERIOR CRUCIATE LIGAMENT: A RESEARCH UPDATE ON THE CANCER OF THE KNEE Luke Bahnmaier MS, ATC/L, OTC Idaho Athletic Trainer’s Association Summer Symposium July 26, 2014

2 Cancer of the Knee? “This is the cancer of the knee!!!”

3 What this IS about….

4 Objectives Epidemiology/Prevalence Factors influencing ACL injury Screening programs Injury prevention programs Return to play Things to consider….

5 First…..

6 Yikes….

7 Epidemiology WE ALREADY KNOW THIS >

8 Factors Influencing ACL Injury Anatomic Hormonal Neuromuscular Modifiable Non-modifiable Quasi- modifiable

9 Anatomic/Developmental Factors Q-Angle Static pelvis and hip alignment Body Mass Index Knee Joint Laxity Femoral Notch Width/Height ACL cross-sectional area/volume/length/ultrastructure Tibiofemoral Joint Geometry/Morphology  Medial and Lateral Posterior Tibial Slope (MTS and PTS)  MTS:PTS ratio  Tibial Plateau Width (TPW), and Depth

10 Anatomic/Developmental Factors Geometric Profile  More important than we thought?

11 Anatomic/Developmental Factors Geometric Profile  More important than we thought? Tibial geometry influences hip and knee joint biomechanics and forces during drop-jump and SL land-and-cut tasks (Schultz and Schmitz, 2010, McLean et al., 2010) Retrospective review of ACL injured patients shows increased posterior tibial slopes, and increased MTS: LTS ratio and shapes (Brandon et al., 2006, Todd et al., 2010) Tibial sub-chondral bone geometry retrospectively predicted ACL injury (Hashemi et al., 2010) Similar findings when tibial articular cartilage is mapped (Beynnon et al., 2014)

12 Anatomic Factors

13 What We Still Don’t Know…. Large-scale, prospective studies to incorporate all LE alignment and geometric measures to determine most susceptible profiles Interaction of joint laxity, tibial geometry, and ACL size on knee joint biomechanics and ACL load Is there a practical tool that can be used to elucidate these measures on the field or in the training room?

14 HORMONES Research suggests females suffer most ACL injuries during the pre- ovulatory (follicular) phase, compared to post-ovulatory (luteal) phase

15 HORMONES Risk of ACL may be higher in female athletes with elevated serum relaxin concentration Sex hormone receptors present on the human ACL  potential direct influence on structure Cyclic variations in knee laxity may result in altered knee biomechanics throughout the menstrual cycle

16 HORMONES What we still don’t know…… Question is….what DO we know?!?!?!

17 Neuromuscular/Biomechanical Extensively researched Neuromuscular measures + Biomechanical measures = Neuromechanics

18 Neuromuscular/Biomechanical What we THINK we know… Move differently than….

19 Neuromuscular/Biomechanical

20 ACL is loaded by combined sagittal and non-sagittal plane loads, compressive and shear forces Knee valgus, internal rotation, and anterior shear forces “Dynamic Valgus” phenomenon… Females vs. Males Females land “stiff”, with less knee and hip flexion Increased VGR forces…rely on passive restraints to absorb energy More “quad dominant” landing patterns Thought to increase anterior shear forces during “stiff” landing Land with increased knee valgus angles

21 Neuromuscular/Biomechanical

22 Practicality….

23 Screening Programs What’s out there? Laboratory 3D Motion Capture Programs Expensive laboratory equipment Very accurate….Very expensive Not practical for on-field utility 2D Video Analysis Less expensive…. Still time intensive Still not very practical (You already have ImPACT baselines…now you’re telling me we need to do a 2D video jumping analysis?!?!?!) Landing Error Scoring System (LESS) Recently developed, easy to implement, based off the BESS test Still requires video analysis, however

24 Screening Programs 3D Motion Capture Systems DARI System, University of Missouri Brett Hayes “It allows us to see the small changes in joint angles, joint torques and even muscular instabilities that are difficult — if not impossible — to measure with the naked eye,” said Brett Hayes, a physical therapist and physical rehabilitation manager for the Missouri Orthopaedic Institute. “We’re able to determine where that specific athlete may have a muscular imbalance, a joint imbalance or basically just a weakness that we can see is a detriment to performance or, in worst cases, we can see as potentially leading to injury if we don’t address it.”

25 Screening Programs Landing Error Scoring System (LESS) Valid and reliable (Padua et al., 2009) Intra- and inter-rater reliability good to excellent (Padua et al., 2009, Onate et al., 2010) LESS scores higher in subjects s/p ACL-R (Bell et al., 2014)

26 Screening Programs Landing Error Scoring System (LESS)…BUT… Smith et al., 2012

27 Injury Prevention Programs

28 Multiple studies have shown training programs correlate with changes in biomechanical profiles thought to be “high- risk” ….So why wouldn’t these programs work to prevent, or reduce, ACL injury? Short answer:…some have shown promising results, though study design has been questionable Long answer:…Talk to Dr. Shea and get his opinion

29 Injury Prevention Programs Hewett and colleagues, AJSM, 1999 Sportsmetrics program 6 week pre-season program 1,263 basketball, soccer, and volleyball athletes for 1 season

30 Injury Prevention Programs Mandelbaum and colleagues, AJSM, 2005 Prevent injury, Enhance Performance (PEP) Program

31 Injury Prevention Programs Gilchrist et al., AJSM 2008 Prevent injury, Enhance Performance (PEP) Program Prospective, RCT of D-1 collegiate female soccer athletes Intervention athletes 3.3 times less likely to suffer NC-ACL Only statistical significance was ACL injuries in practice… Promising trend in a Level I study…how do we interpret?

32 Injury Prevention Programs Pfeiffer and colleagues, JBJS 2006 Boise, Idaho Special! Prospective, non-randomized, two year study Program similar to Sportsmetrics, but less time-intensive

33 Injury Prevention Programs

34 Things to Consider… Retention of movement patterns affected by program duration (Padua et al., AJSM 2012) Current, commercially available training programs may not affect LE biomechanics for youth athletes under the age of 12 (DiStefano et al., AJSM 2011) Numbers needed to treat to prevent 1 non-contact ACL injury over one season is estimated at 108 individuals (Sugimoto et al., Br J Sports Med. 2012) Peripheral and central fatigue, with unanticipated landings, are shown to significantly affect LE biomechanics during landing and cutting….so WHY aren’t we incorporating these into our programs? (McLean and Samorezov 2009, Borotikar 2007, McLean 2007)

35 Return to Sport Ryan Mizner PT, PhD University of Montana Growing body of evidence showing significant asymmetries in landing biomechanics at time of RTS following ACL-R (Paterno et al., 2011, Di Stasi et al., 2013, Delahunt et al., 2012, Webster et al., 2014) Asymmetries retrospectively predicted re-rupture or contra- lateral ACL tear upon RTS (Paterno et al., 2010) Asymmetries present even in those who have passed RTS testing (Di Stasi et al., 2013) Do we need to include 3-D motion analysis in our RTS criteria?

36 Return to Sport: Re-injury Incidence rate of ACL injury following ACL-R 15 times greater than that of controls (Paterno et al., 2012) Females 4X more likely to suffer ACL graft rupture, 6X more likely to suffer contralateral ACL injury 29.5% of 78 patients who underwent ACL-R (Paterno et al., 2014) Risk of second ACL injury 6 times greater in ACL-R group Twice as likely to suffer contralateral ACL injury For patients under 20 s/p ACL-R, odds of suffering ipsilateral and contralateral ACL injury increased 6-, and 3-fold, respectively (Webster et al., 2014)

37 Clinical Take Home Points Critically evaluate research, don’t swallow the “Blue Kool-Aid” Consider modifying current prevention programs to include fatigue, with unanticipated movements Consider assessing jump-landing movement patterns with return to play, access to 3-D motion analysis? Understand that geometric profiles of the tibia may be more important in ACL injury risk than we have historically thought


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