Women’s Health Month: Why Female Athletes are More Prone to ACL Injury

Thanksgiving is coming a little later this year, and so are my blogs on the promised topic of Women’s Health Month. As the weather gets colder and most high schools are starting their basketball seasons around this time of year, I thought a great blog topic would be ACL injury with particular attention to why this injury has a female-athlete predominance.

In 1972, 1 in 27 Varsity sport athletes were female. In 1997, this number drastically increased to about 45%: 55% female: male participation, thanks to Title IX. With this increase, the number of ACL injuries also increased with a notable female predominance to ACL injury. This sex discrepancy in ACL injury begins at puberty and continues into adulthood. Even more so, the number of non-contact ACL injuries is higher in girls than boys, and this is a notable increase in incidence that is also seen from the onset of puberty, age 12 to 14 years in girls. The peak incidence for ACL tear is in the group of 16 to 18 year-old girls, and the highest numbers of ACL injury have shown to be in girls’ soccer: 14 per 100,000 female soccer players vs. 4 per 100,000 male soccer players at the high school level. The second highest incidence is in basketball with the ratio of female: male ACL injuries in this group of high school athletes being 2:1.

So what’s the deal? Why are ACL injuries more common in female athletes? To begin to answer this question, we first have to discuss the biomechanics involved and this boils down to what is an ACL and what does it do…

What is the ACL and what does it do?

The ACL is the anterior cruciate ligament of the knee joint, and it runs from deep within the distal femur (the long bone of the thigh that is above the knee) to the front of the tibia (the bigger bone that makes up the shin). The origin or beginning of the ACL is within the notch of the distal femur and the proximal (beginning) fibers of the ACL fan out along the medial wall of the lateral femoral condyle. The ACL attaches to the tibia on the intercondyloid eminence that is adjacent to the medial meniscus. All of these interactions allow the ACL, along with the PCL (the posterior cruciate ligament) to stabilize the knee joint.

The ACL resists anterior (forward) and medial (sideways toward the middle of the body) movement of the tibia across the femur. In short, it keeps your lower leg from moving forward and rotating inward toward your other leg.

Terrible Triad

Because of the interaction of the surrounding stabilizing structures of the knee joint, a common injury that can occur is called the “Terrible Triad.” You might hear someone say with reference to this injury that they “blew out” their knee. This occurs when there is a tear of the ACL, the MCL (medial cruciate ligament), and the medial meniscus.

So what’s with the ladies?

There are many theories about why ACL injuries are more common in the female athlete. The answers have ranged from differences in female vs. male training, issues with flexibility and ligament laxity, hamstring/quad strength discrepancy, bone structure, and even female hormones. So let’s analyze the data and separate fact from fiction, folks.

Hormones

Like everything that affects women, they’ve tried to blame the female athlete ACL injury predominance on our hormones, ladies, and guess what? The studies are still inconclusive. The most convincing theory is that estrogen receptors on ligaments cause increase ligament laxity in female athletes causing increased risk of ACL tear as opposed to male athletes.

                What supports this theory:

Some studies have found that there are an increased number of ACL tears around the time of ovulation (in the pre-ovulatory and ovulatory phase where estrogen levels peak). Moreover, some studies have shown that oral contraceptive pills have decreased the risk of ACL tear in female athletes. The theory behind this would be that OCPs prevent ovulation, maintain steadier hormone levels, and prevent the changes that make women more susceptible to ACL tear around the time of ovulation. This theory has been supported by evidence showing that early on in puberty there is not as much of a female predominance to ACL tear. Folks have postulated that this is because estrogen does not vary much at this time, i.e. estrogen is not exerting its effects on the neuromuscular system.

                What goes against this theory:

Men have estrogen too. What? Well, they do. But they don’t get the increased joint laxity that is often seen in female athletes. It may be that their receptors respond differently, but the fact is that in both boys and girls after puberty, peripheral testosterone is converted to estrogen, so both sexes have this hormone, which could exert effects on the neuromuscular system. Other studies have also come about to debunk the idea of an ovulatory association with ACL tear. They have found a greater number of ACL tears on cycle days 1 and 2 of the menstrual cycle. These days are during the first part of menstruation or during the early follicular phase of the cycle when levels of estrogen and progesterone are low. So what gives? Maybe this one isn’t actually something we can blame on our hormones, ladies.

Athletic Training and Conditioning

This argument really used to be something to think about back in the day when women were just getting into competitive sports, but now look at us! Go ladies! So proud of where we have taken female sport!!! :) With female athletics taking off and with Title IX giving women the same resources to trainers, physical therapists, strength and conditioning coaches, etc. that male athletes have, we really can’t prove with evidence-based studies that there are specific differences in the type of training that male and female athletes are doing which predisposes women to ACL tears. However, it may be more about what we are NOT doing in our training of female athletes to compensate for the differences in male and female musculoskeletal structure and biomechanics. This idea has been linked to hormones in one study showing that changes in knee joint laxity during the menstrual cycle does affect knee joint loading during movements, which could be important in ACL injury prevention programs and how we are training our athletes. This is just one study done in 2009. So, we need more evidence to come up with better training programs. But up next, what it is about the female musculoskeletal  system that predisposes to ACL injury?

Musculoskeletal Biomechanics

Female athletes are more quad and leg dominant; they rely more on ligaments for stability, and they have increased ligament laxity, especially after puberty. The intercondylar notch of the femur is more A-shaped in the female femur vs. the male femur. Women also have a wider pelvis, which increases knee valgus and causes a greater Q angle.

Bone structure

So what the heck is knee valgus and Q angle? Knee valgus is when the knee deviates inward (knock-knees). In many female athletes, when they jump and land, when they do a deep squat, or when they make a cut to change direction, their feet are externally rotated, and the hip and knee are not very flexed. This posturing causes an increase in Q angle, the angle between the pelvis and the knee. The male Q angle is typically about 14 degrees. The normal female Q angle is about 17 degrees. In persons with patellofemoral pain syndrome (something we can talk about another time), that angle is increased to greater than 22 degrees.

As puberty increases, the female pelvis is becoming and wider and flatter, causing the change in Q angle that we see between male and female athletes. Knee valgus and increased Q angle place increased strain on the ACL because the ACL has to work harder to pull the knee back into normal position and stabilize the knee joint. Taking all of this into consideration, it really does make sense to teach our athletes proper squatting and jumping/landing techniques.

Ligaments

The female ACL may also have a lower percent surface area of collagen.

Muscles

Another consideration is the difference in strength between genders. By age 15-16 years, girls have 75% of the strength that boys have, secondary to increase in lean body mass that is much greater in boys. During puberty, boys increase their hamstring strength by 179% and their quad strength by 148%. On the other hand, girls become more quad dominant than boys do with these changes in strength during puberty.

Moreover, when women experience stress on their ACL, they naturally compensate by activating their quads and lateral hamstrings, which causes increased Q angle. Yikes!

Boys/men seem to fire their semimembranosus (the medial hamstring) later than girls/women do, and this action is thought to be more beneficial in protecting the ACL from injury. It seems that because of these differences, pubescent girls are at greater risk for non-contact ACL injury compared to boys.

Immediate Assessment: Does my child need an MRI?

So we all know that this is my favorite question for athletes and for all pediatric issues. Parents always want to know if their children need cat scans, x-rays, and MRIs. With any injury, it is important to get an assessment from a doctor as close to the injury as possible. Often this does mean going to an Urgent Care Center or Emergency Room as most sporting events take place after regular pediatric or orthopedic office hours. The opportune time for assessment of ACL tear is actually immediately after the injury occurs, so if your team has a Sports Medicine doctor available at the game, this is your best bet. Even waiting until you get to the ER after the game can sometimes make assessing an ACL tear more difficult because the more swelling that occurs, the more difficult it is on physical exam to evaluate the ACL.

Anterior Drawer Test - one of the physical exam tests
to evaluate for ACL tear.

The most important thing is to be evaluated shortly after the injury has occurred. You will not be able to get an emergent MRI, and an MRI is not always necessary in the case of knee injury. Depending on the mechanism of injury and the physical exam, your doctor may think an x-ray is necessary to rule-out fracture. The next step may be an MRI to evaluate ligaments and other soft-tissue damage, depending on the physical exam. Your child does not need a CT or cat-scan. This test is emergently available, but it is not as definitive as MRI and has, as we have previously discussed, a large amount of radiation, and should not be done unless absolutely necessary. Listen to your doctor and ask questions if you do not understand the tests ordered or the plan for the care of your child.

Treatment

Interestingly enough, these days, for an ACL tear, depending on the severity, and depending on the future goals of the athlete, you do not always need surgery! Isn’t that great news? It depends on how severe the tear is and how competitive and lengthy the athlete’s future career will be. It is often helpful to get the opinion of two different orthopedic surgeons before making your decision on surgery. This injury used to be a career-ending injury for many athletes, and now recovery times and strong commitments to rehab have athletes back to jogging in 6 weeks and back to their sport within the same season, depending on when the injury occurs.

Prevention

I hope that what this short article has shown you is that we actually need more studies to show what we should be doing to protect our athletes, what strength and conditioning programs would best help prevent ACL tear. Studies have shown that the types of prevention programs that are in the mix currently have made no difference for kids age 9-12 years in preventing ACL tear; however, they have noted improved technique and better prevention with programs in the age range of 14- to 17-year-olds. These kids may be more susceptible to feedback and coaching at this age, but 9- to 12-year-olds are kids already learning sport-specific skills, and we need to find a program that can work for improving their techniques in order to prevent ACL tear and other injuries. One thing is for sure, our treatments and our rehab have come a long way in helping athletes recover from these injuries, but prevention is definitely the future for our athletes.

References:

Bell DR, et al. The effect of menstrual-cycle phase on hamstring extensibility and muscle stiffness. J Sport Rehabil. 2009 Nov;18(4):553-63.

Bell DR, et al. The effects of oral contraceptive use on muscle stiffness across the menstrual cycle. Clin J Sport Med. 2011 Nov;21(6):467-73.

Dragoo JL, Castillo TN, et al. Serum Relaxin Concentrations and ACL Tears. Journal of Sports Medicine. 2011. 39:2175-2180.

Lefevre N, et al. Anterior cruciate ligament tear during the menstrual cycle in female recreational skiers. Orthop Traumatol Surg Res. 2013 Sep;99(5):571-5.

Park SK, et al. Alterations in knee joint laxity during the menstrual cycle in healthy women leads to increases in joint loads during selected athletic movements. Am J Sports Med. Jun;37(6):1169-77.

Slauterbeck, et al. The Menstrual Cycle, Sex Hormones, and Anterior Cruciate Ligament Injury. Journal of Athletic Training 2002;37(3):275–280.

Wild CY, Steele JR, Munro BJ. Why do girls sustain more anterior cruciate ligament injuries than boys?: a review of the changes in estrogen and musculoskeletal structure and function in puberty. Sports Med. 2012 Sep 1;42(9):733-49.

26.2 miles and 1611 patients

"There's a place deep within yourself you must go to finish a marathon. I run because I can't get enough of that amazing place."

-Running Thoughts (twitter.com/RunningTH)

So this past Sunday was not only the first day with an earlier sunrise and sunset, but also it was the 43rd Annual New York Marathon. I have never run this marathon myself, since after 3 times attempting to get in via the lottery, I got addicted to Ironman instead, but this year, I wanted to try my hand at being a medical volunteer for endurance racing. I have been on the sidelines cheering for friends the last 8 years, and I have to say that there is nothing like the magic of this race and how all of New York comes together to welcome elite and amateur runners from across the globe. 

Last year, many runners were devastated that all of their training seemed like a waste as the race was cancelled due to resources needed to help our tri-state area recover from Hurricane Sandy. I know what it's like to train for 15 months, travel half-way across the world, and then have your race cancelled because I was in New Zealand for the Ironman in 2012. But, as much sympathy as I had for last year's runners, I have to say that the city made the right decision in cancelling the race. Since then, our endurance community has had to recover from even more tragedy, after the bombing at the Boston Marathon last April. 

I think that's why this year's New York Marathon seemed even more triumphant. I didn't cheer on the sidelines this year, but I was working in the P5 medical tent, the most acute tent that sees the most runners each year and handles the race's ambulance transports. We saw 1611 patients on Sunday in P5, including 6 runners who were very ill requiring ambulance transport and acute medical care in our tent. We are so proud of you runners and what you have accomplished and were happy to help make the hobbling home through NYC streets a bit easier...be it with crutches, with warm chicken broth, salt packets, bandages, Zofran, fluids, or other medical care. Thanks to all the volunteers and their support of this great event. 

There are so many great marathon stories each year, but I wanted to share a brief bit from a runner's story included in this week's JackRabbit Newsletter.

"This Sunday, I became a marathoner. Alongside tens of thousands of runners, I traveled 26.2 miles through the streets of New York from the Verrazano Bridge, through Brooklyn, Queens, the Bronx and Manhattan, to the storied New York City Marathon finish line in Central Park. After crossing the finish line, a runner next to me started sobbing and, not knowing what else to do, I hugged him. We didn’t speak to each other, I don’t know his name and odds are we will never see each other again but in that moment I knew we were both feeling the same rush of emotions: shock, disbelief, gratitude and finally a deep sense of calm: it was over, we’d done it, we were marathoners.

I don’t know what brought that runner to the starting line Sunday morning. Maybe he was raising money to cure a disease that had struck a family member, maybe he was a survivor of the Boston bombings, maybe his journey to the marathon was cut short last year by Hurricane Sandy, or maybe he was just in it, like myself, to prove that he could do it. While we all have our own reasons to toe the starting line—or to buy our first pair of running shoes or sign up for our first training program—we can only get to the finish through a combination of dedication, faith in ourselves, and a supportive community."

~Karen's marathon story, from JackRabbit Newsletter, 11/5/13

[As an aside, if you're in the NYC area and are not a JackRabbit member, this might be something to consider, especially to get going this winter. They send out email newsletters with upcoming local races, group workout events, options for training schedules, and so on. It could be a great way to stay motivated this winter! Also check out their stores for triathlon, running, and yoga apparel. Check them out: http://jackrabbitsports.com/]

I completed my first marathon 3 ½ years ago in San Diego, and I can't quite remember what my thoughts were crossing that finish line. All races blend together after a while, but I remember that I had a sense that I had gone to battle and that I had survived and done something that I never thought I could do before that moment of accomplishment. I think I likened it to graduating from medical school, although at that point I had not yet graduated, and medical school felt like the longest endurance race of my life. It seems to me that every time you take your training to the next level, you experience that kind of sentiment and philosophy where you feel you have gone to battle, survived, and come out stronger than you thought you were when you started.

I have to say that in the P5 medical tent on Sunday, with stretchers lined up everywhere, volunteers wheeling and transporting patients on wheelchairs and stretchers, and runners coming in sometimes too weak to stand, teeth chattering, pale or blue, screaming in cramp agony or looking pre-syncopal and woozy, it looked like an endurance battle field to me. 

This was during set-up. Things got too busy for pictures as the day worn on.

It was like the New York Marathon version of MASH. Our soldiers didn't have open bullet wounds or amputated appendages, but they were bleeding from gutsy abrasions won from falling and getting up to complete their 26.2-mile journey; some had broken bones in the form of stress fractures; and others had hobbled along on injuries earned during months of training. These were our soldiers who had come to race for their respective countries, and we were proud to care for them and get them safely home.

What a great day! If that doesn't make you want to do an endurance race, folks, I don’t know what will ;) Set a goal for yourself that is reachable but requires work this winter, and see how far your journey can take you, what character you build, and how many wonderful people you have in your life who will support and encourage you along the way and be so very proud of your accomplishment at the finish.

Winter Fitness, Part 1: Feeling SAD? exercise away winter blues!

It's becoming that time of year folks. We wonder if we are really working that much longer, or is it just that the days are getting that much shorter and we are leaving and returning home in darkness? The leaves are still beautiful, but as the ghouls and goblins come out for the tricks and treats, you can't help but notice that the time change is upon us, the end of daylight savings time has arrived, and so has the beginning of winter. :(

For the record, that used to not give me a frowny face. But the more time you spend in colder climates with longer nights and less daylight, the more your childish whimsical love of snowflakes and snow angels just turns into-- "Oh, great, another Nor'easter, time to shovel and see if I can get to work in this mess." This is so unfortunate because winter can be a fun time—hot cocoa, snuggling, fire places, caroling, holiday celebrations, baked goods… The problem is that some of us gain ten pounds just reading that list and the rest of us just think about how cold we are going to be and that going for a run is going to be the LAST thing on our to-do list this holiday season.

So while last week was particularly gray on most days, and I was very thankful for how bright and colorful our autumn leaves were since they felt like the only sunshine my serotonin-deprived brain was getting, it occurred to me that a very nice topic for this week’s blog would be seasonal affective disorder and how great a treatment exercise is!

But first a bit about SAD.

Is it real?

As a dear friend would say, “YOU BETCHA!” This is a real thing. SAD is a type of depression that occurs seasonally. Usually people with SAD get depressive symptoms that begin each year around fall and continue through the winter months. You may feel tired, moody, or have difficulty getting out of bed or getting going in the morning. My resident friends are reading this and thinking, “Wait, isn’t that just residency?” It may be partly SAD!

People who do shift work, night shifts, or are used to brighter and warmer climates may have more depressive symptoms in the winter time and have more difficulty coping with these issues. People who live in areas with long winter nights are also at greater risk of SAD.

Symptoms:

Hopelessness

Increased appetite or weight gain

Increased sleep

Less energy

Inability to concentrate

Loss of interest in work or other activities

Sluggishness

Social withdrawal

Unhappiness and irritability

SAD can also become long-term depression or even develop into bipolar disorder. If severe, people can experience suicidal thoughts.

What’s going on in the brain?

The pathophysiology of seasonal affective disorder is still somewhat unclear and may be a biologically heterogeneous entity that results from a combination of factors including difference in genetics, altered neurotransmitters (serotonin, norepinephrine, and dopamine), and changes in circadian rhythm.

Several studies have linked SAD to changes in serotonin and even genes that influence levels of serotonin in the brain. One study of female participants even linked these changes to a possible hypothesis of why some people with SAD have increased eating behavior. Many studies have shown that natural light is a helpful treatment for SAD, and so it has been hypothesized that SAD results from circadian rhythm changes that occur when the brain is not stimulated as much by natural light during the winter months, making people sleepier and more sluggish.

There is also an association between SAD and adults who have residual ADHD symptoms. Dopamine and low central arousal in both ADHD and SAD are the linking factors to establish a connection between the association found in these patients. Neuroimaging studies have even shown a decrease in global cerebral metabolism of dopamine in both persons with ADHD and with SAD.

So, you betcha, folks, no matter what factors are leading to this disease, it is a real issue and something that many of us have to somehow cope with. I never knew how important sunshine was to me until I moved to New York, and after 11 New York winters, I can tell you one thing—I’m ready to move! ...and I love New York! But, apparently, my brain loves serotonin more. So, since most of us New Yorkers are stubborn and don’t want to leave, and since there are folks living in climates way colder and with way less daylight, I thought maybe we could go over some ways to deal with this thing called SAD.

What's the cure?

EXERCISE!

Obviously I'm very happy to say that getting 30 minutes of fresh-air exercise or just getting 30 minutes of exercise if you can't do the fresh air is what helps treat SAD because I think exercise pretty much cures everything...but you guys, it's true! Get some fresh air, get your body moving, get some adrenaline going, and watch that frown turn upside down :) It's hard to be sad and feel sorry for yourself when you're trying to run a certain speed or when you're listening to great music on the elliptical machine or feeling the relaxing buoyancy of an indoor pool. Find what works for you and go for it!

Buy an SAD light

I mentioned before the studies supporting this as a treatment for SAD. There are lots of options out there. I kind of refused to spend the money on this for a long time, and my wonderful friend who also struggles with SAD bought me one as a present last year. That SAD light during my weeks of night shifts and during the winter of intern year was my salvation. It may be partially placebo, but it really makes me feel more awake than regular indoor lighting fixtures do. Try what I found helpful and couple turning on your SAD light with the indoor workout of your choice. I always turn on my SAD light on rainy/snowy days when I am doing an indoor biking workout on the trainer. :)

Be a the-glass-is-half-full kind of person

At least you’re not living in one of these 25 coldest cities: http://www.thedailybeast.com/galleries/2010/12/10/america-s-25-coldest-cities.html#slide25

That doesn’t always work, since sometimes cold pictures make you more depressed. 

Subliminal advertising

Bora Bora, French Polynesia

Plan a warm vacation. Evidence shows that just planning a trip makes you happy.

No time? Pull out pics from your last beach trip and think about how nice that sunshine was—take 5-10 minutes and do a little Zen time where you imagine yourself back there each day or whenever you need it. Make a slideshow for your computer, set yourself up with a beach desktop background--it's the little things that count.

Not working? Better yet, try TAKING a warm vacation! :-P

Throw a party!

Planning a mid-winter party is the best way to catch up with friends and have a good time without even having to venture out into the cold yourself. Make a theme, do a potluck, eat wine and cheese, play board games together. One of my co-residents had a great idea to crank up the heat in his apartment and have a beach-themed party with frozen umbrella drinks. It's five o'clock somewhere, and maybe it can even be Margaritaville in your apartment. So what if you don’t have the money or the time for that Bahamas vacation—you have one weekend, and that’s all you need!

winter running can be fun! especially
when your running buddy thinks you're nuts!

Start a winter workout club!

Grab a group of friends and instead of getting hammered after work (we all know that is sometimes helpful, but it can get old and can add to your winter wobbliness), meet up for boxing class (Shout out to Leah Nelson for doing this!!!!) or spinning class or group polar-bear runs (Snow runs can be fun! Especially since they give you an excuse for hot chocolate afterward--the perfect winter recovery drink!) instead.

Set your sights on a spring or early summer race!

My SAD was never better than when I was Ironman training. Snowing outside? No problem. 5 hours on the bike trainer and a Rocky movie marathon it is! It doesn't have to be an Ironman; it can be a 5k, a 10k, a half-marathon, a tough mudder, a zombie race—anything that’s going to make you go get on the treadmill when it’s cold and you would rather stay under those covers.

What to do when your comforter says: “I’m warm and comfy too, baby.”

http://www.youtube.com/watch?v=qTvJ8clMWX0

Just do exactly what this girl does and get out and run! Or go flip on your SAD light, eat some breakfast, and then go run, but the sooner you are in fresh air, the more awake and ready for the day you will feel. Make gym dates with friends to make sure you don't ignore your alarm and succumb to the warm comforter trap.

You knew I was going to give you like 3 tips that didn’t involve exercise and then a slew of tips that do because this is a Sports Medicine blog, but if you are feeling a little gray as the days get shorter, just try a workout program and bring along a friend if you want, and you will be surprised how much it helps, trust me.

TAKE ADVANTAGE!

Now is the perfect time to make this positive change in your life because we just had the time change and our bodies haven’t caught up yet! You are primed to go to bed early and to wake up early because you have already been doing it for the last several months! Stay on the same schedule, trick your brain, and get up early before work and start your day right—with exercise J You will thank yourself for the rest of the day with more energy, more smiles, and more excitement about having your evening free from the dread of needing to go to the gym. Just remember to hydrate :-P

A few more tips on ways to add happiness to your life:

http://www.themindunleashed.org/2013/10/10-easy-things-that-will-make-you.html

(exercise is of course the first one!)

Remember to be thankful for sunshine in all its forms and to keep those exercise-endorphins pumping to fight SAD this winter.

Talk to your doctor.

So, I pretty much recommend exercise for every ailment, but I also recommend talking with your doctor. Obviously, this blog has a lot of tips that can help most people with depressive symptoms, but for some folks, daily exercise, planning trips, and SAD lights are not enough. Sometimes you need a little help to get going and get started with some of these fixes, and it can really help to see your primary care provider and ask about other treatments. Anti-depressive medications and psychotherapy are used together to treat SAD and other forms of depression. Especially if you have had trouble with depression in the past or are thinking about harming yourself, please tell your doctor. If you are having thoughts of suicide, call one of the following helplines or go to your nearest emergency room.

References/More Info:

National Hopeline Network: 1-800-SUICIDE

National Suicide Hotlines and Info: http://suicidehotlines.com/national.html

Suicide Hotlines for NY: http://suicidehotlines.net/newyork.html

RW Lam and RD Levitan. Pathophysiology of seasonal affective disorder: a review. J Psychiatry Neurosci v.25(5); Nov 2000.

http://www.mayoclinic.com/health/seasonal-affective-disorder/DS00195