Tag: cartilage

Hip Hip Hooray: Joint Functionality Can Be Restored After Hip Labral Tear

Do you experience deep, sharp pain in your groin? Or a feeling of “catching” or “popping” in your hip joint as you go about your daily activities? Is your range of motion you once had now severely limited? If so, you could be experiencing symptoms of a hip acetabular labrum tear, an ever-increasing problem in society that fortunately, has effective treatments.

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Pressurized Vessels Supporting the Spine: Structure and Function of Intervertebral Discs

Back in 1989, it was estimated that about 2.5 million U.S. workers suffered from low back pain, and low back pain has even been talked about as one of the largest causes of disability in the world. Intervertebral disc degeneration is one of the most common reasons for low back pain in adults. In order to understand how disc degeneration occurs and causes pain, it is important to examine the structure and function of discs in the back.

Computer generated image of a healthy lumbar spine
Vertebral Column: Obtained from Smart Servier Medical Art

Discs are structures that sit in between vertebrae in the spine (blue in the image). Their consistency has been compared to Jell-O and the seemingly mythical product called the waterbed. This consistency comes about because of the microstructure of the discs. The main structural component is collagen which not only surrounds the discs but also traverses across the fluid-filled center to give support. Collagen is found all over the body in places ranging from bones to eyes. There are many different types of collagen that are able to account for the softness of the cornea and the strength and stiffness of bones. In discs in the back, the collagen that traverses the middle is the same as that found in cartilage, while the collagen that makes up the outer layer is the same collagen found in skin and bones. This gives the discs a strong, thin outer layer surrounding the gel-like center, warranting the comparison to the waterbed.

Because of this structure, intervertebral discs provide support for the spine in compression. The spine can be compressed by activities as simple as carrying a backpack, sitting, or bending over. When these and other activities occur, the vertebrae press in on the discs, causing pressures from about 15 to 300 psi, or pounds per square inch, depending on the activity. For reference, the recommended tire pressure for a car is 30-35 psi and the pressure inside a champagne bottle is 60-90 psi.

As discs degenerate, either with age or trauma, they respond differently to the large compressive stress applied from the spine. With age, this change in response is most commonly attributed to the inside portion of the disc drying up and changing from a gel to a solid. Discs rely heavily on fluid flowing through their pores, and once they dry up, this no longer occurs. As loads are applied, instead of increasing pressure, degenerate discs can expand outward creating a phenomenon known as a bulging disc. While this is just one of the many medical problems a degenerate disc can cause, it is

Computer generated image of a lumbar spine with disc herniation.
Disc Herniation: Obtained from Smart Servier Medical Art

common and typically leads to an increase in pain. When the discs expand outwards, it reduces the space between the vertebrae causing irritation. If the discs expand far enough outward, they can leave the space between the vertebrae, entering the region where many nerves lie, potentially causing pain throughout the body.

Despite their odd consistency, intervertebral discs play an important role in the spine, sometimes pressurizing to more than 3 times that of a champagne bottle. Both injuries and natural degeneration leads to negative changes in the biomechanical properties of discs, causing an increase in back pain. If you are interested in learning how to take care of your discs, worried you have an injured disc, or simply want to learn more, I recommend going here.

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

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