Are Preventable Injuries Putting Military At Risk?

Anterior Cruciate Ligament (ACL) injuries are some of the most common and costly injuries in sports.  In sports, we know the mechanics associated with these injuries also place athletes at risk for other non-contact injuries of the lower extremity.  But are these same movement patterns also related to increase risk in other physical occupations?  Are the movement patterns that common in the military?  Are military personnel, like athletes, at risk for ACL injuries and are they preventable?  If they were prevented, what would be the impact on all other injuries?  

Throughout history, US military personnel have had a hard time correlating the mechanics seen in sports to the military personnel.  But is that the case in all countries.  Not necessarily.  For example, in Brazil the military does screen their military for the mechanics associated with non-contact lower extremity injuries. Doing so, they have had a huge impact on non-contact lower extremity injuries.  Considering that this accounts for over 70% of their injuries, the financial impact is profound.  Are they more progressive or know something that no one else does?  Yes and no. Since Brazilian athletes are intimately integrated with the military bases, it gives the health care providers a very unique perspective in comparison of the athlete to the solider.  In essence, they are one in the same. But what do the studies tell us?

According to Uhorchak et al in a study published in the American Journal of Sports Medicine in 2003, the same movement patterns that are associated with ACL injuries in athletics also predispose US military cadets for ACL injuries.   Boling et al demonstrated in 2009 that these same movement patterns also lead to patellofemoral (PF) pain syndrome in military recruits and if identified can reduce risk for ACL injuries as well as PF pain.  We know in high school athletics that ACL injuries results in an annual cost of ~$1.3B to $2.7B in health care costs but is there a similar cost associated with preventable injuries in the military?

Looking at data published from the Department of Defense from 2005/2009, the numbers of preventable musculoskeletal injuries are staggering.  When you look at the ones that are associated with the same biomechanics associated with ACL injuries, you see the following: 

Top 10 Department of Defense Injuries and DLD (days limited duty):

·        #1 LE overuse injuries – 3.8M days

·        #5 LE sprains/strains – 1.8 M days

·        #6 LE dislocations (ACL/cartilage) – 1.5M days

·        #8 Spine – 1.2 M days

·        Total – 8.3 M days of missed duty – days that must be replaced

The cost associated with replacement of those who are out due to injury is $689/injury $350,000,000 in extra labor cost for the military on an annual basis.  When you add in the medical cost to this, it is truly unbelievable. 

·        Medical costs for musculoskeletal injuries (non-traumatic) account for $343,000,000/year (not including PT follow-ups)

·        Total cost (medical, DLD and long term disability) is $3021/musculoskeletal injury or $1,500,000,000 of the $1T dollar annual health care cost.

 Despite the cost in both the civilian world and the military, few have figured out how to significantly impact these results in a positive way.  

According to the Defense Medical Surveillance System, 2010, musculoskeletal injuries account for the largest percentage of the 1.2M medical encounters in the US Army in 2010.  33.9% of these were the result of non-battle injuries and over 60% of those were preventable non-contact musculoskeletal injuries.  In 2009, of the >1100 serious injuries that occurred at Ft. Jackson, over 85% were the result of overtraining and are therefore preventable.  Sports studies show that improvement of mechanics associated with non-contact ACL injuries results in >60% reduction in all these non-contact lower limb injuries.  


For example, lets look at a study by Waterman et al, published in the American Journal of Sports Medicine 2013, the authors looked at anterior compartment syndrome and what are the risk factors that predispose service members for.  The intent is to identify risk factors so that prevention techniques can be employed. 

Methods:  This was a retrospective analysis of US active duty military personnel with diagnosed nontraumatic exertional anterior compartment syndrome between 2006 and 2011.  Demographic and occupational risk factors such as sex, age, race, branch of the military and rank were analyzed.

Results:  A total of 4100 cases were identified within the at risk population.  Overall incidence rate for the duration of the study was .49 cases per 1000 person years.  There was also an annual increase over the 5 year span of the study with .06 cases per 1000 person years in 2006 to .33 cases per 1000 person years in 2010.  Risk factors included:

·        Sex - females (.52 cases per 1000 person years) were at greater risk than males (.49 cases per 1000 person years)

·        Military rank – Junior/senior enlisted (.53 cases per 1000 person years) were at much higher risk than junior/senior officers (.33/.25 cases per 1000 person years)

·        Branch of the military – risk by branch is listed in descending order by risk:

o   Army - .65 cases per 1000 person years

o   Air Force - .59 cases per 1000 person years

o   Marine Corps - .37 cases per 1000 person years

o   Navy - .23 cases per 1000 years. 

Discussion:  Based on the data presented, injury rates are on the rise.  Many feel this may be result of a less physically fit recruit today than 10 years ago.  Whatever the case may be, the net result is increased injury rates, increased short and long term cost and decreased re-enlistment rates.  Although the data above makes a lot of sense, what does it tell us about “root  cause”?  Is this information that we can use to prevent these types of injuries in the military.  Can we change one’s gender or their rank in the military?  No.  But it can guide us if we can correlate this data with existing research.  For example, we know from Weist et al, research in 2004 that prolonged running results in fatigue in the lower kinetic chain.  This adds to:

·        Increase metatarsal pressures – pressures on the bones of the forefoot

·        Increased rear foot pronation

·        Decreased maximal volitional contraction of the gluteus medius and maximus – resulting in increased valgus loading of the lower limb

Collectively, these add to decreased force attenuation along the kinetic chain and can result in shin splints which can lead to anterior compartment syndrome.  We also know from Chappell et al in 2005 that this fatigue that leads to the poor biomechanics at the knee leads to increased shear stress on the ACL, meniscus and patellofemoral joint.  So considering the above results, it makes sense why the results are what they are.  All the previous studies show that these movement patterns are more prevalent in females and with fatigue.  Since junior and senior enlisted will be running more as a part of their requirements than officers will, then makes sense why they have more anterior compartment syndrome.

All this said, it goes down to what do we do about it and how can we positively influence to reduce injury rates in the military?

1.      Identify the movements that put service members at risk.  We have done that and there are over 15 years of research in this area.  We know when someone lands in a position like this that there is decreased force attenuation along the entire kinetic chain and increase stress to the tissues.

2.      Identify what the root causes are for the movement patterns.  Zeller et al as well as many others have identified what the root causes for these movement patterns are.

3.      Develop a way to assess these with movement so that it leads to the root cause and corrective techniques to improve.  

How does Brazil do it? The Dynamic Movement Assessment™. The DMA™ is a movement assessment that uses the movements that highlight these abnormal movements and methodically guides to the root cause and intervention. With the release of the new Microsoft #Kinectv2 and integration with this movement assessment, the 3D-DMA™ provides a fully automated, reliable and sensitive measure of movements known to directly put athletes and military personnel at risk for injury.

Unless we look at the movement associated with non-contact movement related injuries, we will never truly identify the “root cause”.  Until we identify the root cause, we will continue to be only marginally effective at reducing injury rates.