ACL Tear Or Not (Differential Diagnosis)

ACL tears can sometimes be confused with other injuries, especailly when it happens to a younger athletes. Even though increased number of ACL injuries in younger athletes are seen, it is still rare compared to older population. Since, in those younger athletes, the weak link is their growth plate instead of the ligament itself, an injury to open growth plate (physis) becomes more common. The ligament can pull a piece of bone off of tibial plateau, which can happen by the same mechanisms of injury as an ACL tear. This can be detected by plain films. This injury is also different from ACL tears in that this can be repaired surgicaly not having to have it reconstructed.

Another injury that can be confused with ACL tears is petalla subluxation. This is due to similarities of both injuries. They both happen from similiar mechanisms of injury. Clinical presentations are similiar, such as immediate swelling, loss of motion, etc. Another reason for this is that medical professionals have to a tendency to think "knee injury = ligament injury?!" Those medical professionals need to do a thourough evaluation of the injury to avoid misdiagnosis.

A key to a quick recovery from an injury that has happended is to find out what the injury is and have it taken care of early and appropriately.

With patellar subluxation, the patella (knee cap) dislocates and it goes back in place by itself. So, there is no need for reduction. It may need to be immobilized, however. Most of the times, the patella dislocates/subluxes lateraly.

When To Wait, When Not To.

Sometimes, unfortunately, injuries do happen. Injuries like ACL tears usually require surgery. However, it is not easy to make a decision and have a surgical procedure done, psychologically and timing-wise. Sometimes, it is wise to have it done right away. Sometimes, the athlete can wait. This decision making should be done considering the severity of the injury, recovery time, etc.

Rehab after ACL reconstruction takes about 5-6 months. This means, for some sports, the end of a season. Let's say the injured athlete is a professional baseball player and gets injured during spring training. This means that he will be more than likey miss the entire season. And his goal will become returning to the field the next season. If he gets surgery done by June, he will have enough time to get ready for the following season. However, he has about 3 months to make his mind up. In his case, he has an option to try to rehab his knee until then. If it works, he may be able to play. If not, he can go ahead and get a procedure done.

On the other hand, let's say the injured athlete is a 16 year-old soccer player who plays for a club team and for high school. In this case, her soccer season is pretty much all year around. It will probably better for her to have surgery done sooner because the longer she waits the longer her return to play will be.

Some cases are more complicated than these cases. But final decision should be made by the injured athlete (and parents if the athlete is a minor), not the surgeon or coach.

How To Prevent ACL Injury

Even though ACL injuries can be devastating, a risk of injury can be reduced. There are several strategies that can be used. Since mechanisms of an ACL injury are multi-factorial, the several factors should be considered when implementing a prevention program. Especially those at a higher risk of ACL injury can benefit from the program.

Here are some of the risk factors that can be eliminated or controlled.





Muscle Imbalance

There are two big muscle groups in the thigh, the quads and hamstrings. The quads are usually stronger than the hamstrings. However, if the hamstring strength drops below a certain % of the quad strength, the athlete may be at risk. An intact ACL prevents tibia (shin bone) from shifting forward on femur (thigh bone). When the quads and hamstrings co-contract with the knee straight or slightly bent, the quads pull tibia forward, which also puts stress on ACL, on the other hand, the hamstrings pull it back helping ACL keep tibia from shifting forward. If the hamstring are not strong enough to pull against the quads' counter force, it may put more stress on ACL than the balanced knee. By eliminating the hamstring strength deficit and having balanced muscle groups, a risk of ACL injury can be decreased.





Side-To-Side Difference

Muscle imbalance can also happen between the limbs. This happens when one leg is significantly stronger than the other. When the difference is more than 15%, it is considered significant. This does not necessarily mean that the athlete will get hurt but it means that he/she may be more at risk of injury. This is another risk factor that can eliminated doing some simple strengthening exercises.




Core Stability


Decreased core stability has been linked to lower leg injuries. Core training may not be as simple as strengthening leg muscles. However, it can be easily done without using much equipment and can be implemented as a part of regular training session (as warm-up or cool-down). An athlete may have strong arm and leg muscles, but if he/she does not have stable core, those muscle strength will go wasted. Even an athlete who can move and change directions quickly on the field will not be able to use his/her agility effectively and efficiently without stable core musculature. It will make it a lot harder for those who do not have core stability to defend themselves from an injury when they are off-balance and when they lose a control of their body. The athlete with good core stability will be able to regain their postural control even when it is lost.

Here are some examples of core exercises.








Proprioception


Proprioception is a position sensor located around the joints. If you raise your arm with your eyes closed, you can tell approximately where your arm is. This is because you have proprioceptors giving you information on where your arm is even without any visual feedback. This is the reason why you do not have to be looking at your feet all the time when you play soccer. Good proprioception not only helps athletes' performance but also keeps them from injuries.



Neuromuscular Training


This targets on teaching athletes how to do things the right way in neuromuscular level. Muscles only work when they get a signal from the nervous system. And they respond to it in the way that they are told to. If athletes are introduced to a new skill, the nervous system will send a signal telling the muscles to do what they are supposed to do. It may take some time and practice until they learn to perform the new skill. In the same way, this training focuses on how to use the muscles correctly to do athletic movement patterns the right way so that the athletes will have less risk of injury.

This video shows one exercise that can be used to teach athletes how their legs should be used on landing.

ACL Injury: Who's At More Risk?

There are athletes that are more subject to an ACL injury than the others. Gender, sports they participate in, muscle balance/strength, biomechanics, etc. Some risk factors can be fixed/eliminated, but some may not. Injuries cannot always be avoided, however, it is a lot easier to prevent it than to rehabilitate after surgery.

Female

Female athletes are shown to be 4-6 time more at risk of ACL injuries than male counterparts. This may not sound fair but it is the fact that just being female increases the risk.

Sports

Certain sports have a higher injury rate than others. Those high risk sports include soccer, gymnastics, basketball, football, skiing, etc. ACL injuries can also happen in other sports such as tennis, baseball, and softball, but not as common as in sports listed above.

Previous Injury

Athletes who have had an ACL injury previously may be prone to re-injuring the same or the opposite knee. Some research articles deny it, on the other hand, there are research articles that have proven this is the fact.

Muscle Imbalance

Athletes who have side-to-side muscle imbalance may be more at risk. These athletes have one leg that is stronger than the other. Also, muscle imbalance can occur between two muscle groups (quadriceps and hamstrings). Usually, the quads are stronger than the hamstrings. But if hamstring strength drops below a certain percentage of quad strength, the athlete may be at a higher risk of injury.

Core Strength/Proprioception

Decreased core strength and proprioception have been linked to lower leg injuries. Core strength and proprioception play an important role in postural control and inability to control posture during athletic activities well will put the athletes at risk of injuries.

Biomechanics

There have been numerous research articles that studied biomechanical differences during landing and athletic activities. Athletes with biomechanical deficit are the ones whose knees bend inwardly during landing. This tends to happen more in female athletes. Female athletes also tend to keep their knees straighter compared to male athletes, which is also considered to be a risk factor. As a result, these athletes may not be able to absorb a GRF (ground reaction force) and their knee may be sustaining higher GRF.

Maturation

After growth spur, body weight and height increase drastically. As peak growth occurs, their muscle strength needs to increase in order to support increased body weight. Male athletes seem to successfully be able to get stronger as they grow, however, this adjustment does not seem to happen to females, leading to a gender difference in muscle strength after growth spur. This may be linked to a higher injury rate in female athletes after puberty.


There may be other risk factors. Athletes who participate in high risk sports should be participating in a prevention program as well as those who are considered to be at a higher risk of injury.

ACL Injury: Contact vs. Non-Contact

An ACL injury happens frequently in sports such as soccer, gymnastics, skiing, football, etc. And female athletes may be 4-6 times more prone to an injury than male counterparts. Even though it happens more often in contact sports, about 75% 0f the injury happens without involving a contact with another player. It has gotten more attention because of the seriousness of the injury and many research articles regarding the issue have been published. As a result, we know more about how the injury happens, what factors are involved, who may be more prone, how to prevent it, etc.

Contact ACL Injury

A common mechanism of contact ACL injury involves falling down while being tackled in the knee or lower leg, which forces the knee into valgus motion (knee bending in). The foot usually is planted on the ground by a tackling athlete and it becomes difficult to control his lower legs and the body. It can also happen when an athlete is tackled in the front of the leg causing the knee to hyperextend.



Non-Contact ACL Injury

A non-contact ACL injury occurs more frequently than contact ACL injury. It is common in soccer, basketball, gymnastics, skiing, etc. Athletes may sustain this injury when they are try to stop and make a quick change in direction leaving the foot planted on the ground while the body is being twisted. Another mechanism of injury is landing and hyperextending the knee. It also happens when the knee collapses into valgus on landing. The athlete usually does not have a good control of the body when he/she gets hurt.



A contact ACL injury is harder to predict, however, a non-contact ACL injury can be prevented by implementing balance training, proprioception training, strengthening exercises, neuromuscular program, etc.

Sports Medicine Myth: No Pain No Gain?!

There are many people (parents, coaches, etc) say that no pain no gain. But is it true? No so much when you are injured. Pain usually is a signal that there is something not right. You have pain when you twist your ankle because you just damaged (injured) a ligament in the ankle. When doing rehab and trying to come back from an injury, it is not a good idea to keep doing what causes pain.

Soreness is difference from pain. You get sore after lifting weights and doing training that you are not used to, etc. And it goes away in a day or two. It is ok to be sore as long as it goes away. It is a natural response of your body.

But sometimes, you may have to deal with some pain during physical therapy. Let's say you had an ACL reconstructed. The first thing you do is to reduce inflammation. Then, you try to regain lost range of motions. In this phase of rehab, you will be pushed and have some (a lot of) pain to get the range of motion back quickly. Rehabilitation is not pain-free. It sometimes is painful. It can be challenging what pain is ok and what pain is not ok.

So, is it ok to play through pain when you get hurt during practice? The best thing to do is to stop doing what you are doing and take a break. In youth sports, often times there is no health care professional on site to take a look at an injured athlete right away. So, when you are in doubt, the best thing is to not do what causes pain. You do not want to keep playing when injured not knowing what is wrong and make things worse.

High Ankle Sprain: Why Is It More Difficult To Treat?

High ankle sprains are different from (lateral) ankle sprains. They happen to a different part of the ankle. Instead of happening to the outside of the ankle, this involves ligaments located right above the ankle joint that connect two bones of the lower leg (tibia and fibula). The way it happens is also different. Instead of twisting the ankle, an athlete usually lands awkwardly forcing the ankle to dorsiflex. He/she may land on someone's foot or an object. In young athletes, (growth plate) fractures or avulsion fractures may also happen, especially the mechanism of injury involves twisting motion.

But why is it more difficult to treat? The reason is that it puts stress on the ligament every time the injured ankle bears body weight. When you take a step, a ground reaction force (GRF) from the ground is transmitted through the ankle forcing tibia and fibula to separate from each other. Anterior tibiofubular ligament (the most commonly injured ligament in high ankle sprains) holds the bones together. However, in an injured ankle, this puts stress on the ligament causing the pain. Depending of the severity of the injury, the athlete may be on crutches until pain resolves, or partial weight-bearing. Also, most ankle braces are designed to prevent lateral ankle sprains and do not prevent high ankle sprains.

Especially, in sports that involve lots of jumping such as basketball, volleyball, gymnastics, etc., it may be more difficult injury than lateral ankle sprains.