Tag Archives: joints

Arthritis is NOT Just For The Elderly: Early Signs Of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that, according to the Arthritis Foundation, affects 1.5 million people in the US. Women are 3 times more likely to develop RA and are usually diagnosed between ages 30 and 60, while men are rarely diagnosed before the age of 45 . Unlike osteoarthritis which is caused by wear and tear on joint cartilage over time, RA is caused by an overactive immune system that triggers unnecessary inflammation responses. One effect of this is that the body attacks its own joints causing swelling, stiffness, and chronic joint pain as well as irreversible damage. This limits joint mobility and decreases the quality of life for those impacted by it, especially those diagnosed as children or young adults.

This disease cannot be cured but treatments like medicine or dietary/ lifestyle changes are most effective when diagnosis happens early. When joint damage occurs it is irreversible, meaning the only treatment option is surgery. The joints most commonly affected in the early stages of this disease are finger joints which are usually the first sign of inflammation and will be the focus of this article. The image below shows the progression of finger joint damage in a patient with RA starting with no damage (a) to severe damage (c).

As an RA patient, a typical visit to your doctor would always include a pain/inflammation assessment. With a focus is on early stages of RA, fingers and hands would be the most important areas to look at. Each joint of focus would be felt by your doctor to check for swelling and tenderness, but the most important aspect is the patient’s self-assessment of inflammation and pain. It is important for patients to accurately assess their pain and mobility in order to find a medicine or treatment that works effectively. This was the focus of a study that was conducted on 52 RA patients (33 women and 19 men) which used a variety of tests in an attempt to quantify arthritis damage and compare it to the predictions made my patients.


The first test looked at range of motion for fingers flexed (in a fist) and extended (straightened). The next test measured grip strength in different positions like using a pencil, opening a jar or turning a key by using a device that measured the force produced by the hand in each position. Stiffness was measured visually, and pain levels were also recorded, but it should be noted that pain cannot accurately be quantified because pain tolerances vary among patients. The result of this study was that the patients predictions on grip strength and stiffness best correlated to the real results and were therefore the best predictors of hand function. This means that patient reports of strength and stiffness are the most accurate and helpful to be used by doctors when choosing medications or treatment plans.


Because joint damage from RA cannot be reversed, surgery is usually the only option to repair damaged joints, and even surgery will not bring back full mobility. Because RA treatments (both medicines and surgery options) are still very new there isn’t widely available or reliable data on the impact of hand surgery. Additionally, with the increasing use of the newer class of biologic drugs there has been a noticeable decrease in damage to the synovial tissue (the specialized tissue between the bones in any given joint) and the need for hand surgery has significantly decreased because of this. Overall, a variety of surgeries are available and there is almost always a tradeoff between mobility, vanity and elimination of pain. It is up to the patient, doctor, and surgeon to decide the best treatment option.

Overall, it is important to listen to your body and look out for early signs of RA to avoid lasting joint damage. This is especially important if you have a family history of RA. Early symptoms include, redness, pain, stiffness and swelling at joints, a lack of muscle strength, decreased range of motion/mobility, and even unexplained fatigue or fever.


References and Further Reading

Ankle Sprains: An Epidemic in the World of Athletics

Have you ever been out running on a gorgeous fall day, only to have the run cut short by a painful misstep on a tree root covered by leaves? I have, and let me tell you – it’s awful! And even if you aren’t a runner, according to the Sports Medicine Research Manual, ankle sprains are a common, if not the most common, injury for sports involving lower body movements. Now, the solution to preventing this painful and annoying injury could be as simple as avoiding tree roots and uneven ground, but the real problem behind ankle sprains deals with the anatomy of the ankle.

The ankle is made up of many ligaments, bones, and muscles. However, when sprained, it is the ligaments that are mainly affected. Connecting bone to bone, ligaments are used to support and stabilize joints to prevent overextensions and other injuries. The weaker a ligament is, the easier it is to injure. There are three main lateral (outer) ligaments supporting the ankle joint that can become problematic: the anterior talofibular ligament, the calcaneofibular ligament and the posterior talofibular ligament. According to a study from Physiopedia, these lateral ligaments are weaker than those on the interior (medial) of the ankle, with the anterior talofibular ligament being the weakest.

An image depicting the various ligaments of the ankle, both lateral and medial.
Anatomy of the ankle, highlighting the lateral and medial ligaments

The next question that has to be asked is why are these ligaments so much weaker than other ones? The answer to this question is based on their physical make up. Ligaments are made of soft tissue that has various collagen fibers running parallel to each other throughout it. The more fibers there are, the more structure and rigidity there is. Think of the fibers as a rope: The rope can stretch to a certain point, but once it hits that point it will snap and break. But if you have a thicker rope (such as the medial ligaments), it becomes much harder to break.

The ligaments on the outer part of the ankle have fewer collagen fibers than those on the inside of the ankle. Thus, when the ankle is moved in an awkward position, it is more likely that the lateral ligaments will break.

Once you sprain your ankle, the focus turns to treatment. Treatment will differ slightly for every individual depending on the severity of the ankle sprain. The simplest way to treat a sprained ankle is to follow the RICE (Rest, Ice, Compression, Elevation) method. Other forms of treatment include taping the ankle or using a brace to restrict movement and to add support and extra stability. Wearing proper footwear is another way that one can prevent and help treat a sprained ankle, as certain shoes are specifically designed to help avoid such injuries. To prevent future ankle sprains, exercises are recommended to help strengthen and stabilize the joint and surrounding ligaments and muscles.

For more information on ankle anatomy and sprains, check out these articles on BOFAS and SPORTS-Health.

In the Womb: Alive and Kicking

For a pregnant woman, it can be a thrilling moment when her baby kicks for the first time. Women have described the feeling as a flutter, a tumble, or a gentle thud. However, these movements are not only exciting because they are unpredictable but because they indicate healthy fetal development. 

Although a pregnant woman may not feel her baby’s kicks and punches until 18 to 25 weeks of pregnancy, fetal movement may begin as early as seven weeks and science shows that it is crucial in the development of joints and bones. In fact, a lack of fetal movement can be a sign of abnormal musculoskeletal development and other poor birth outcomes. In the last decade, scientists have begun to wonder how mechanical factors have positive or negative effects on a baby in utero. 

MRI scan animation of developing fetuses
An animation composes of MRI scans of fetal movement during various stages of development. (Image: © Stefaan W. Verbruggen, et al./Journal of the Royal Society)

In particular, researchers Stefaan Verbruggen and Niamh Nowlan at Imperial College in London decided to take a deeper look at the mechanics of these fetal movements through several different studies. As it turns out, neonates can throw a pretty strong punch. In one experiment, researchers saw that fetal kicks can incur an impact of 6 lbs at 20 weeks, 10 lbs at 30 weeks, and less than 4 lbs beyond 30 weeks of pregnancy. The force of fetal kicks decrease after 30 weeks due to the limited amount of space for the baby to move. 

In addition, the force of fetal kicking was also observed in three different neonatal positions: typical (head-first), breech (feet first), and twin fetuses. These studies revealed that twin fetuses can exert the same amount of kick force and motion as a healthy singleton fetus in the typical head-first position. However, fetuses in the breech position showed significantly lower kick forces and lower stress and strain in their hip and knee joints. This discovery might explain why babies in the breech position have the highest probability of being born with hip problems.

simulated strain concentrations in a fetal leg
Simulation of principal strain which indicates that strain increases with gestational age for fetuses in the head first position.  Modified from Verbruggen et al., 2018.

 In another study, three mothers volunteered to have their wombs monitored via MRI so that the researchers could observe the geometry, force, and frequency of fetal motion. It was found that fetal muscles are able to produce nearly 40 times more force than the kick itself. The magnitude of force exerted by these muscles confirms the importance of fetal kicks for proper growth of the hip and knee joints. This information is helping scientists and doctors connect the dots between neonatal environment and newborn joint abnormalities.

Interested in learning more? Check out some of the new technology being developed to further this study!

The Weight of Combat: Are powered exoskeletons the solution to heavy combat loads?

Have you ever wondered how much weight a soldier carries in a combat zone?

Military servicemembers, particularly those in physically demanding roles such as infantry, are routinely required to carry heavy combat loads ranging from 25- to over 100-lbs. This load potentially includes weapons, ammunition, body armor, food, sleeping equipment, and other necessities for the mission. Consider that these loads are often carried for hours or even days at a time in both deployed and non-deployed environments and it becomes clear that these loads take a physical toll on those who bear them.

The physiological demands of these loads often lead to servicemember injury or discomfort both during and after their time in service. The most common musculoskeletal injuries resulting from carrying heavy combat loads include increased lower back pain and injuries to the knee, ankle, and spinal cord. Such injuries lead to acute and chronic effects over the servicemembers’ lifetimes, increased military healthcare costs, and decreased military readiness.

While it would be advantageous to decrease both the weight of the combat load as well as the frequency of weight-bearing events, the reality of modern warfare gives little hope to these suggestions. However, there is another solution: external, electrically powered exoskeletons to aid with carrying combat loads.

American defense and technology company Lockheed Martin is currently developing a prototype exoskeleton for military use – the ONYX exoskeleton. Two prior-service soldiers are shown performing common physical tasks under load – walking up a steep incline and walking up flights of stairs – while aided by the exoskeleton. Both soldiers involved in the test indicated a high level of comfort with the exoskeleton as well as improved weight-bearing ability using the ONYX exoskeleton. Check out the video to learn more:

Powered exoskeletons come with drawbacks, namely mobility/comfort issues and the need for a mobile, long-lasting power source. While the devices may perform well in a laboratory or controlled setting, reliability in the field will require durable materials and electronics. Additionally, while Lockheed-Martin’s ONYX exoskeleton is designed to reduce load on the wearer’s knees and quadriceps muscles, it gives no such support to the lower back or other parts of the body. This shift in load distribution throughout the body may have unintended consequences and potentially lead to further injury. A 2006 study by researchers at Loughborough University in the UK found that existing military load carriage systems result in gait and posture changes (head on neck angle, trunk angle, etc.) which lead to muscle tensions that increase one’s risk for injury.

A figure visualizing the angles made by the head, torso, and legs when walking
Image taken from Attwells et al., Ergonomics, 2006.

Thus, while there have been many improvements in robotic and soft electronics technology in recent years, powered exoskeletons have much to prove before they see time in service.

What do you think – are powered exoskeletons going to be commonplace on the battlefields of tomorrow, or are they a passing fad?

For more information, check out the following articles from the Army Times and Breaking Defense on the ONYX exoskeleton.

What Makes Someone More Likely to Tear Their UCL?

It takes a lot to make a professional athlete collapse to the ground during a game. After throwing a pitch on September 14, 2019, Toronto Blue Jays pitcher Tim Mayza knelt on the side of the mound while clutching his arm, expecting the worst. The next day, MRI revealed that what he had feared: Mayza had torn his Ulnar Collateral Ligament (UCL).

player following through after throwing baseball
Photo by Keith Johnston on Unsplash

Because of UCL reconstruction, or Tommy John, surgery, this injury is no longer the career death-sentence that it once was, but there is still a long road ahead for Mayza. He probably will not pitch in a game again until 2021. Sadly, this injury is only becoming more and more common among MLB pitchers. In the 1990s, there were 33 reported cases of UCL tears by MLB pitchers. In the 2000s, this number more than tripled to 101. From 2010 to the beginning of the 2015 MLB season, 113 UCL reconstruction surgeries had already been conducted. It has become so common that surgeons have called it an epidemic, and researchers in the US and abroad are attempting to find a way to combat this increase.

Digital image of elbow joint, with a small, red tear in the UCL
Orthopaedic and Neurosurgery Specialists, 2019

The UCL connects the ulna and humerus at the elbow joint, and its purpose is to stabilize the arm. During the overhead pitching motion, the body rotates in order to accelerate the arm and ball quickly, putting a large amount of stress on the UCL. In fact, according to a study by the American Sports Medicine Institute, the torque, or twisting force, experienced by the UCL during pitching is very close to the maximum load that the UCL can sustain.

Recently, many studies have investigated factors that could make pitchers more susceptible to UCL injuries, with a hope of identifying ways to prevent them. One of the biggest findings has been the correlation between UCL tears and pitch velocity. According to a study from the Rush University Medical Center, there is a steady increase in the frequency of UCL tears as max velocity increases. This makes intuitive sense, as more torque would be required to accelerate a baseball to the higher velocities. While this finding does have a very strong correlation, it does not help the players avoid injuries. Pitchers are unlikely reduce their velocity because it would also decrease their effectiveness, so another answer must be found.

The University of Michigan conducted another study, and found that, in addition to velocity, the number of rest days between appearances decreased by just under a full day for pitchers who later needed Tommy John surgery. While this does not seem like a large number, starting pitchers typically only receive 4 days of rest between starts, so the extra .8 days is equivalent to a 20% increase in rest time.

Because of these findings, the MLB has increased the max roster size from 25 to 26 for the 2020 season, with the hope that teams will use the extra player to reduce the frequency that each pitcher is used. In addition, pitch counts in Little League Baseball have had a positive effect on youth injuries. This can be explored further here. This discovery has already made a tangible impact on Major League Baseball, and hopefully more findings will reduce the rate of UCL tears in the future.

Canine Hip Dysplasia: What You Should Know

Canine hip dysplasia (CHD) is a degenerative hip disease that tends to develop in large breed dogs, such as the Bernese Mountain Dog, affectionately referred to as Berners. CHD significantly decreases the quality of life of a dog and often leads to complete immobility if left untreated. Experts estimate that about 28% of Berners are affected by dysplastic hips, making them the 8th most susceptible dog breed.

Bernese mountain dog with superimposed image of hip ball and socket joint.
Image from Packerland Veterinary Clinic.

At birth, puppy skeletal structures are largely composed of cartilage that is much softer than bone. This softer cartilage is able to adapt much more easily to the rapid growth that occurs during the early months of a dog’s life. In their first few months, Berners will typically gain 2-4 pounds per week, which adds increasingly large stresses to their developing bones and joints. While genetics play a large role in the susceptibility of a dog to develop CHD, the loading cycles and forces on the cartilage greatly shape the development of the dog’s hip.

Correctly formed hip versus a deformed femur head and shallow hip socket.
Image from Dog Breed Health.

The hip is a ball and socket joint, where the head of the femur, the very top of the dog’s leg, should fit perfectly into a socket in the pelvis. If the ligaments that hold the femur in the hip socket are too weak or damaged at all, the positioning of the

Evenly distributed forces on a correctly developed hip joint versus force concentration acting on a dysplastic hip joint.
Modified from The Institute of Canine Biology.

hip joint will be off and the hip will be subjected to unbalanced forces and stresses over the course of the dog’s life. The distribution of forces experienced by the hip joint in normal hips is evenly spread, while dysplastic hips are subjected to a stress concentration on the tip of the femur. These unnatural forces will cause laxity in the hip joint, leading to instability, pain, and often times the development of osteoarthritis.

 

There are also a number of environmental factors, many of which are inherent to large dog breeds, that dramatically increase a dog’s susceptibility to CHD. A study by Dr. Wayne Riser concluded that factors such as oversized head and feet, stocky body type with thick, loose skin, early rapid growth, poor gait coordination, and tendency of indulgent appetite all contributed to the development of CHD. All of these features are generally inherent to large breed dogs, such as Berners, so great care must be taken in order to mitigate their effects on the quality of life for these dogs.

Multiple studies have shown that treatment that is implemented early in the dog’s life is much more effective than late-in-life treatments. CHD warning signs can be seen in puppies as young as 4 months old, and most veterinary professionals agree that if scans occur at 2 years of age, the most optimal time for treatment has passed. Since larger stresses will be put on the hip joint as the dog grows, surgical repairs, or changes in diet and exercise, are most effective if implemented before the dog’s skeletal frame is completely developed.

 

timeline of canine hip dysplasia development
Modified from The Institute of Canine Biology

Additional information regarding this topic can be found at The US National Library of Medicine or The Journal of Veterinary Pathology.

The Shoulder: Super Joint or Super Hazard?

The shoulder joint is one of the most incredible joints in the human body.  Humans have been recorded throwing 100+ mph fastballs, pressing nearly 600lbs overhead, and performing incredible gymnastics moves. The shoulder is a ball-and-socket joint, and it is by far the most mobile joint in the human body.  But this great range of motion comes at the price of being the most unstable joint in the body.

The contact between the shoulder blade and the humerus (upper arm) is analogous to the contact between a golf ball and golf tee.  A golf ball is perched precariously on top of a tee, and can be removed from its resting place with very little force.  Thankfully, the shoulder joint is a bit more complex than a golf tee, giving it more stability.  However, it is still very weak in relation to the rest of the human body, as it is only held together by the four, small rotator cuff muscles, the glenoid labrum, the biceps tendon, and several ligaments.

graphic of a shoulder joint with muscles, tendons, and bones labelled
Image from Wikipedia

One of the most common shoulder injuries is a shoulder dislocation.   This injury occurs about 200,000 times per year.  This injury occurs most often in men in their 20s and in men and women above age 60.  The younger group sustains this injury most often from a violent incident, either from a sports injury or a motor vehicle accident.  The older age group sustains this injury mostly from non-violent injuries, such as falling.  This causes a tear in the labrum, resulting in future instability.

image showing the difference between a healthy labrum and a torn labrum
Image from Huang Orthopaedics

The labrum is a cartilaginous ridge around the joint that adds stability by creating a seal between the humerus and shoulder blade.  Returning to the golf ball analogy, the labrum is like a rubber ring around the top of the golf tee that helps keep the ball from falling off.  When this is torn, it does not often heal, as there is very little blood flow in the shoulder joint.  This tear remains and makes it more likely for future dislocations to occur.

This lack of stability can be addressed both surgically and non-surgically.  Non-surgically is generally the preferred, but less successful option.  It involves strengthening the shoulder muscles to make up for the lost stability of the labrum.  The rotator cuff muscles as well as other larger muscles are strengthened to compensate for the torn labrum.  While the muscles can help immensely with reducing instability, they cannot always entirely replace the labrum.  If this is the case, surgery can be done to re-attach the labrum and give the shoulder nearly all the stability that it had prior to the tear.

One example of someone who had this surgery and then returned to a near pre-injury level of function is Saints’ quarterback, Drew Brees. Brees suffered a torn labrum and had it repaired with twelve anchors. He then would return to the NFL and become one of the greatest quarterbacks of all time.  He was the MVP of Super Bowl XLIV and is a twelve-time Pro-Bowler.  A labral tear can be devastating, but as can be seen by Brees’ story, it can be overcome. So while the shoulder comes with its fair share of liabilities, it is still one of the most impressive joints in the body.

 

Sources and Further Reading:

The Story of Drew Brees and the ‘1 in 500 Injury’ That Couldn’t Stop His Historic Career

Mayo Clinic – Dislocated Shoulder

Huang Orthopaedics – Shoulder Dislocation and Instability

Teach Me Anatomy – The Shoulder Joint

PMC – Anterior Shoulder Dislocation

Exciting Advance in ACL Repair

Anterior Cruciate Ligament (ACL) injuries are among the most common in sports, with nearly 100,000 tears annually. Additionally, the rate of pediatric tears has been increasing at a rate of 2.3% each year for the past 20 years. The high incidence of this injury is in part due to the structure of the knee complex, where the ACL is located. The ACL helps connect the two longest bones in the body and is responsible for rotation and transferring body weight to the ankle. Specifically, the primary functions of the ACL are to prevent the tibia from sliding too far in front of the femur and to provide rotational stability to the joint. This rotational motion, combined with a lack of muscle support at the knee, is why so many athletes tear their ACL. A recent paper looked into how a team of doctors led by Dr. Martha Murray at Boston Children’s Hospital have come up with a promising new approach to repairing the injured ligament.

Two side views of the knee joint, one showing a healthy knee and one showing a complete ACL tear.
Photo by BruceBlaus on wikimedia.org

Due to its environment, ACLs do not repair on their own like other ligaments do. The synovial fluid, which resides in the knee complex to reduce friction in the joint, limits blood flow to the ACL and PCL (posterior cruciate ligament). When injuries occur to these ligaments, the lack of blood flow prevents clotting. In most other ligaments, clotting would occur and would function as a “bridge” for the two ends of the torn ligament to grow and heal across. Due to ACLs not being able to undergo this process, the current method for repair is to take a graft from the patient’s hamstring or patella and replace the torn ACL with the new graft. While this method is typically successful, Dr. Murray’s team estimates that the re-tear rate is about 20% and up to 80% of patients develop arthritis in their knee 15-20 years after the surgery. To combat this, Dr. Murray drew inspiration from how other ligaments heal and developed Bridge Enhanced ACL Repair (BEAR). The premise of this technology is to take a “sponge” that is composed of proteins that are naturally found in the ACL, and insert it between the torn ends of the ACL.  Using sutures, the sponge is moved into position and the two ends of the ACL are pulled into the sponge. Blood is then drawn from the patient and inserted into the sponge. This environment acts as a blood clot and stimulates the ACL to repair itself. Clinical trials have shown that the sponge resorbs completely after 8 weeks, at which point the two ends of the torn ACL have begun to join back together. While the BEAR treatment is still relatively new, early results are encouraging with patients seeing similar results to patients that undergo traditional ACL reconstruction. Though it is difficult to predict the rate at which patients who receive BEAR treatment will develop arthritis, animal testing has shown lower instances of osteoarthritis development, which is promising news for those who suffer from this common injury.

For more information about the BEAR technology check out Boston Children’s Hospital website or this recent article. A short video detailing the technology can also be seen below.

Female Athletes Compete Against Higher Risk of ACL Injuries Than Males

Female athletes face a greater rate of anterior cruciate ligament (ACL) rupture than males. According to Dr. Karen Sutton and Dr. James Bullock from the Department of Orthopaedics and Rehabilitation at Yale University, female athletes are 2 to 8 times more likely to tear their ACL than male athletes. The majority of these injuries (more than two-thirds) are from non-contact situations. A variety of anatomical, biomechanical, and hormonal factors attempt to explain this difference.

Female soccer player stretching her leg
Photo by rawpixel on Unsplash

Differences between female and male lower-body anatomy show the disparity in Q-Angle that results
Taken from Desrosiers, Soccer Nation 2018

Some anatomical factors that help stabilize the knee joint and may be linked to ACL injuries include: the quadriceps angle (Q angle), tibial slope, and intercondylar notch. The Q angle is the angle formed between the upper leg at the hip joint and the lower leg at the knee joint. This angle tends to be 3.4-4.9 degrees greater in females than males when measured in a standing position. The figure at right shows the Q angle difference between men and women that is caused by anatomical differences including a wider pelvis in females. A greater Q angle causes more strain on the quadriceps muscle away from the centerline of the body, which can affect the position of the ACL to be more prone to rupture.

Tibial slope is a quantity used to describe the position of the tibia relative to the femur. When the tibia is positioned more forward than the femur there is a greater posterior tibial slope and therefore increased ACL strain. On average, females have shown to have a greater tibial slope, which may contribute to the higher incidence of ACL injuries. The figure below illustrates the biomechanics of posterior tibial slope: the effect of the knee joint compressive load (down arrow) and the force of the quadriceps (up arrow) result in an anterior shear force, causing anterior translation of the tibia relative to the femur (right-directional arrow) .

Biomechanical force diagram describing posterior tibial slope
Modified from Sutton and Bullock, JAAOS 2013

In terms of biomechanical differences between men and women, women have greater natural muscle contractions for movement away from the centerline of the body. This translates to a difference in landing positions for women compared to men – females tend to land more straight, creating more force on the knee joint, while males absorb the impact better by naturally flexing their knees upon landing. The hamstring to quadriceps ratio (H:Q ratio) is the functional strength of the hamstring muscles (peak torque) relative to the strength of the quadriceps in motion. Poor muscle strength has been linked to higher risk of lower extremity injury. Males have the ability to increase their H:Q ratio during sport motion, but females fail to do so. Women have also shown greater internal rotation laxity – slackness or lack of tension in a ligament – than men. Generalized laxity was also significantly greater among individuals who suffered a noncontact ACL injury compared to an uninjured control group.

Hormonal factors are an additional consideration that researchers have explored, but the results have been inconclusive in making a direct link between hormone levels and the rate of ACL injury.

Additional reading on this topic can be found at VeryWellHealth and SoccerNation. The following video shows some advice for female ACL injury prevention.

 

Striking Out the Myths behind the Curveball

Anybody who has played baseball growing up was probably told “Don’t start throwing a curveball until you are ‘X’ years old.” That “X” in there for the age was normally around fifteen or sixteen years old depending on who you asked. When an eager, young ball player responded with “Why,” it was normally answered by “Because you will hurt your elbow and shoulder.” No sixth or seventh grade kid is really going to question that statement beyond asking another adult, and subsequently getting the same answer. Likewise, no youth baseball coach has really put in the effort to research whether or not learning to throw a curveball is detrimental health of young athletes.

A study was recently conducted by professionals at Elite Sports Medicine at Connecticut Children’s Medical Center to find out the answer. The study was aimed to analyze the shoulder and elbow joints of several teenage pitchers as they threw multiple fastballs and curveballs. They were specifically looking at the moments put on the elbow and shoulder and comparing those between pitches. A moment is a measure of a force on an object and the distance away from the object the force is being applied, mostly resulting in rotation. A moment can also be thought of as torque.

This image shows the grip and wrist position for a curveball
From McGraw, How to Play Baseball, a Manual for Boys

After warming up, the athletes selected for the study had reflective markers placed on their body. These markers assisted in gathering information for “3-Dimensional motion analysis”. This analysis allows the researchers to record “kinematic and kinetic data for the upper extremities, lower extremities, thorax, and pelvis” for both the fastball and the curveball. The researchers found that the moments in the shoulder and in the elbow are lower when throwing a curveball compared to a fastball. This means that the rotational force put on the joints is actually less severe in a curveball than a fastball. The only thing found that is more intense in a curveball than a fastball is the force on the wrist ulnar, which is used when making the motion trying to touch the wrist to the pinky finger. The wrist and forearm motion and forces were the only significant differences between the two pitches.

From this data it is easy to see that the reason for not learning curveballs at a young age has nothing to do with shoulder and elbow injury. There may be a reason related to wrist injury, but that is yet to be explored. A fastball is actually harder on the joints than a curveball. For whatever reason, youth coaches have always preached not to throw curveballs until you absolutely need to. They may have their reasons, but science has shown that it is not realistic to blame injuries.

For further reading on this topic, please see these articles from Driveline Baseball, The New York Times, and Sports Illustrated.