Tag Archives: knee

Tearing and repairing the meniscus

How does someone go from being the youngest NBA MVP one year to barely making headlines the next? Ask Derrick Rose. After being named the youngest MVP in the NBA, Derrick Rose tears his ACL the next year and then tears his right meniscus twice in the span of three years. Knee injuries have not been kind to Derick Rose, but how does one tear their meniscus and how does it get repaired?

The meniscus is shown in Figure 1.

Showcases the location of the meniscus in the knee. Gives the user an image of how the meniscus works, and where it is located.
Figure 1

According to Sports Health, the meniscus is a type of cartilage that provides cushioning between the bones in the knee. The meniscus main role is to absorb shock and the impact on the leg and knee when it is in motion. It allows for stability and smooth motion between the joints.

In a game of basketball, one of the biggest sports in the United States, there is plenty of running, jumping to shoot the ball into the basket, jumping up to catch a rebound, and doing sharp cuts during the game to shake off a defender. All these movements cause high loading on the knee, and if there is an over-rotation on the knee during these movements, then it can cause a tear in the meniscus. The video below shows when Derrick Rose tore his meniscus.

In the video, it shows Derrick Rose doing a relatively easy movement, he plants his foot in order to change direction to chase after the ball. It is a non-contact movement, but due to an awkward landing on his foot, he gets injured and misses games for the rest of the season.

When the meniscus is torn, there are two options in terms of healing the tear. The options are getting the meniscus removed or getting it repaired. Both options have their own recovery time. If you get the meniscus removed, then the recovery time would be from four to six weeks. However, there are setbacks to getting the meniscus removed such as leading to early arthritis. If the meniscus is repaired, then the timetable to return to play is around six months. According to USA Today , he chose to get the meniscus repaired in order to not have future complications around his knee, which is why he had to sit out for the rest of the season. Going this route also gave Derrick Rose the chance to return to his playing form before injury. According to Stein, 96.2% of athletes that undergo meniscal repair go to pre-injury level of activity after the repair, which is good news for Derick Rose.

However, Derrick Rose tore his meniscus again the following season in 2015. He would then have surgery to remove the damaged part of the meniscus and would return in a couple of weeks. This would then be his third surgery to repair his knee, and his surgeries must have an effect on his playing performance. After these surgeries, the world waits to see if Derrick Rose can reach MVP status again during his career. It would be tragic to see that these knee injuries would ruin someone’s career.

Sources and Additional readings:

General information about the meniscus

Meniscal Injuries in the NBA

Injuries in the WNBA

Brace yourself… You might need surgery

A surgery? For my PCL? Could be more likely than you think.

Usually hiding behind it’s annoying and commonly ruptured brother the ACL, the PCL (posterior cruciate ligament) is a durable ligament that usually doesn’t cause problems for athletes… until it does.

Because of the strong nature of the ligament, injuries that tear the PCL are usually sudden and traumatic. Think car accidents, falling hard on a bent knee… you get the picture. When enough force is applied to the top of the tibia, the tibia can be pushed backwards, past the threshold of the PCL. Even though the PCL does its best to hold your femur and tibia together in the right spot, it just doesn’t hold up to the brute force of a dashboard. These injuries can usually be diagnosed by the presence of a “sag.” When your doctor holds your bent knee up, it looks like your shin bone is sagging underneath your knee. This is your torn PCL crying for aid.

A photo showing the location of the PCL and ACL inside of the right knee. The ACL crosses from left to right over the PCL. Both are attached at the top to the femur and at the bottom to the tibia.

When it comes to fixing these injuries, the nonsurgical approach has typically been recommended for low-grade tears that don’t totally rip the PCL apart. These braces are attached to the leg right above the knee, and are supposed to hold the bottom part of your leg under the knee in place. This prevents from your knee from going too far forwards and backwards, and allows scar tissue to build up over your PCL. While your body tries to heal itself with scar tissue, you will work with a physical therapist to build up your quad strength and restore your range of motion. Over 80% of athletes are able to return to play after bracing their knees.

A PCL brace is shown in place on a knee. There are two stabilizing straps above the knee, and two below the knee. They are connected by a metal frame that meets at a hinge joint over the side of the knee.

However, surgery, which was once only reserved for extreme PCL tears, is now seen as a viable, cost-efficient option for even low-grade tears. PCL surgery is intended to restore normal knee biomechanics and stability to about 90% of their post-injury strength. Sometimes, a part of the Achilles tendon is used to create a graft, or a “new” PCL. This is called an allograft, and results in safer and shorter surgeries (8). Within a month, the athlete can walk and bear their own weight. After six months, athletes are able to return to sports.

In theory, surgery sounds like the most “permanently good” option there is for fixing your PCL. However, no scientific studies have yet been done that can accurately compare the return-to-play rates, or even the relative healing of people in braces versus people who immediately got surgery. When people don’t comply with their treatment plans (aka, take off their braces early, skip physical therapy after surgery, etc.) the data for comparisons between bracing and getting surgery aren’t clear. While your PCL may be out of commission, so is the jury on this one. At the end of the day, the best treatment method for you is dependent on the mechanism of injury, severity of your injury, and whether you plan on listening to your doctor or not!

For more info on PCLs:

Posterior Cruciate Ligament Injury

Management of PCL tears

ACL Reconstruction: Which Option Is Best For You?

200,000 ACL injuries occur each year, and ACL reconstruction is the 6th most performed surgery in the United States, so to come back bigger, faster, and stronger, the right recovery path is critical.

The anterior cruciate ligament (ACL) is a critical part of the knee joint that connects the femur (‘thighbone’) to the tibia (‘shinbone’). Its main functions are to support the knee joint during side-to-side motion, such as cutting, shuffling, or pivoting, and to prevent the tibia from moving too far forward relative to the femur. When an ACL ruptures, it is very common to reconstruct it to bring someone back to performance level.

Location of the ACL inside the knee joint with other labeled bones and ligaments with another diagram showing a ruptured ACL.
Image from Wikimedia Commons “Anterior Cruciate Ligament”

The basis of ACL reconstruction is using living tissue, also known as grafts, to replace, and function as a substitute, for the torn ACL. There are four types of ACL reconstruction surgeries that use different types of grafts. Those four types of surgeries are classified as autograft reconstruction, allograft reconstruction, xenograft reconstruction, and synthetic reconstruction. Autograft surgeries require one’s own grafts to repair the ACL, allografts require a cadaver’s grafts to repair the ACL, xenografts require an animal’s grafts, and synthetics require manufactured materials. Additional articles on xenograft reconstruction and synthetic reconstruction can be accessed here and here.

Each surgery requires the removal of the damaged ACL, and then the incorporation of a new substitute by tunneling the newly selected graft through the femur and tibia. Within the autograft group, the two popular grafts for reconstruction are patellar tendon and hamstring tendon, with quadricep tendon being another, less popular, choice. The patellar tendon surgery takes the middle third of the patellar tendon, a tendon that connects the kneecap to the tibia, and makes sure to include the bony ends.

The hamstring tendon surgery takes two small slivers of each of the two hamstring tendons, connecting the hamstring muscle to the tibia, coils them up, and then finally bundling them to increase strength.

A knee joint with bones, ligaments, and tendons labeled.
Image from Wikipedia “Knee Joint”

For the allograft surgeries, a surgeon may select an Achilles, patellar, hamstring, or quadricep tendon from the donor.

It is very important to choose the right surgery. While the determination of which surgery and technique to perform falls heavily on the surgeon’s and patient’s preference, there are advantages and disadvantages of each technique which tend to persuade the choice of surgery. The main concepts surrounding the decision of which surgery to perform are the activeness of the patient, muscle strength, and previous knee injuries. Depending on the job, sport, or activity of the patient and the desired return time, one technique may be a better fit.

For a patient participating in low demand activities, allograft surgery may be the best fit due to less post-surgery pain and quicker surgery time, however it is very expensive and offers less tensile strength compared to autografts. As for autograft surgeries, patellar tendon reconstruction allows faster recovery time due to the bone-to-bone bonding and offers a strong substitute for a torn ACL, however future knee pain is very common. Hamstring tendon reconstruction requires more recovery time; however, the post-surgery pain is significantly less than the patellar tendon reconstruction and the tensile strength of the hamstring tendon is the strongest possible substitute.

Additional reading and comparisons between the popular autografts and allograft techniques can be accessed here and here.

Patellar Tendinitis: The Kryptonite of Jumping Athletes

Volleyball is a sport of quick movements. For hitters, one of the most common movements in the game is the jump, whether that be to block or to hit. Although a higher vertical leads to improvement in game performance, it can increase the risk of developing a serious injury that affects many volleyball players: patellar tendinitis. This condition is associated with pain and tenderness directly below the knee cap that is especially apparent during explosive, jumping movements. But what exactly causes this condition? And what can be done to remedy it?

A schematic of the knee and patellar tendon.
Image from Wikipedia “Patellar Tendinitis”

Since volleyball is such a quick game, muscle memory is required to react to different situations that can occur. The main way to build muscle memory is repetition. Therefore, young volleyball players are encouraged to play the sport as much as possible. For many athletes, this means playing for their school during that season and then playing for an independent club for the rest of the year. Although this increases the athlete’s skill level, it also increases the chance of patellar tendinitis, according to a study.

Besides overuse, lack of ankle mobility can also lead to a higher risk of the condition. A study found that players that couldn’t flex their ankle upward past 45 degrees could have 2 times the risk of patellar tendinitis as players with a higher ankle mobility. This is most likely due to the ankle and calf’s role in absorbing impact upon landing. Less absorption by the ankle causes more force to be put on the patellar tendon. This is bad news for volleyball players who often have poor ankle mobility due to a past injury.

There are a few ways to treat patellar tendinitis. For an orthotic approach, players use straps or tape around their patellar tendon. Some think this is simply due to the fact that the strap or tape makes the athlete feel more stable, which allows them to load the tendon more properly. However, a study done in 2011 analyzed the strain in the patellar tendon using a computational model. The researchers found that the patellar tendon strap increased the angle between the tendon and the kneecap, which caused the strain to decrease. Decreased strain means that the tendon stretches less, which would decrease the incidence of patellar tendinitis. Another way to treat the condition is surgically. One of the more simple surgeries is a removal of the dead or torn tissue of the patellar tendon. This allows new, healthy tissue to form.

A strap being put around the patellar tendon that can ease pain.
Image from Sports Injury Clinic “Patella Tendon Taping”

Patellar tendinitis is a serious condition affecting many high-level athletes. Although there isn’t a simple cure, researchers have brought to light different causes and treatments of the condition. These can be used to help athletes remedy the pain they are experiencing and perform at their best.

Sources:

Study on How Vertical Affects Patellar Tendinitis

Study on How Training Volume Affects Patellar Tendinitis

Ankle Flexion Study

Patellar Tendon Strap Proprioception Study

Patellar Tendon Strain After Applying a Strap

Additional Reading:

Clinical Trial on Patellar Tendon Strap

Runner’s Knee: Knee Pain Isn’t Just for Old People

Don’t knee problems only plague old people or people who have run for a lifetime? I questioned this when, for the seventh time in a row, my knee was hurting only a mile and a half into my run. I’m too young for this! However, a plethora of information suggests that knee pain is perhaps not so uncommon in younger runners and athletes as I thought.

The American Family Physican published an article detailing one form of knee injury informally called “Runner’s Knee”. A shockingly high number, between 16 and 25 percent, of running related injuries fall into this categorization. Medically termed patellofemoral pain syndrome (PFPS), the ailment manifests in pain or stiffness in the knee, particularly when bent in load-bearing scenarios such as walking, running, jumping, or squatting. The patellar region experiences shocking loads even in the day to day: in walking alone the region experiences up to a half the person’s body weight while in an activity like squatting it can experience up to seven times one’s body weight. Often the pain is hard to pinpoint but occurs in or around the front of the knee within a circular range. It can inhibit or put a stop to training, however, if addressed early on, can often be healed or corrected much more quickly.

an animated image of a runner mid-stride with the pain region for patellofemoral pain syndrome highlighted
Photo by www.scientificanimations.com from Wikimedia Commons

In PFPS, the patella (the kneecap) moves abnormally within the groove on the end of the femur (called the femoral trochlear groove) due to imbalanced or unusual loads on the joint. This results in over-stressing the joint and causing pain. Several possible causes exist for PFPS; here, I will focus on three of most commonly cited: increased intensity of activity, weak hip muscles, and overpronation.

an image of the muscular and skeletal structure of the knee, including the patella
Photo by BruceBlaus on Wikimedia Commons

Increased Activity

One review explored that women are more likely to suffer from PFPS. In this study they saw that women of higher activity levels were not necessarily more likely to experience pain due to PFPS than women who had a lower activity level. Rather, a substantial increase in activity level seemed to be the cause of pain. Therefore, more than overuse of muscles or joints, PFPS often develops with increased amounts of activity, or temporary overuse, such that the body is not prepared to handle the increased and repetitive forces on the knee.

Weakness in Hip Muscle Strength 

This study shows that lower extremity mechanics and motion can be affected by hip strength. For example, inward rotation of the hip can be lessened through strengthening of hip muscles that counteract that rotation. With less internal hip rotation, the knee abduction moment (the tendency of the knee, due to reaction forces from the ground, to rotate  inward and away from the balanced midline of the knee joint) decreased which often resulted in less stress in the knee. Therefore, the review suggests that strengthening hip muscles can lower the patellofemoral joint stress and help treat PFPS. 

Overpronation

Pronation refers to the natural movement of one’s foot and ankle slightly inward while stepping. When the ankle rotates too far inwards, it is called overpronation. Overpronation can lead to further improper structural alignment in the lower body as the tibia rotates improperly in response to the ankle rotation. The tibia’s rotation then disrupts the natural movement of the patellar joint and can contribute to PFPS. In many cases, overpronation can be corrected through use of orthotic shoe inserts that prevent the over-rotation of the foot and ankle.

In conclusion, while we may often associate knee problems with older people or arthritis, PFPS affects many athletes, particularly runners, at any age. Often, proper training programs that do not accelerate activity too quickly, strengthening exercises that focus on the hip muscles, and proper, overpronation-correcting footwear can treat or prevent an individual from being affected by PFPS. Check out some strengthening exercises here.

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.