CBD - What Does The Science Say?

I've been getting a lot of questions about CBD products.  CBD or Cannabidiol, is a chemical that is derived from plants in the Cannabaceae family.  This includes hemp as well as it's more mind-altering cousin, marijuana.

The FDA is actively updating its policy on the sale and regulation of CBD containing products.  CBD was actively investigated first as a drug, so the FDA did a lot of work studying it's safety and uses.  See this article released by the FDA on January 15, 2019. During their investigation, they found that CBD is generally safe.  However, they issue several warnings about possible drug interactions CBD can have. The FDA issued this warning to consumers regarding the potential harms or misleading claims of CBD companies. They note that CBD can cause liver damage as well as male reproductive toxicity.  Currently, CBD has only been cleared by the FDA as a medicine for use in Epilepsy (Epidiolex).  It is restricted from sale as a dietary supplement or food additive.

Image from FDA website

But hang on.  CBD is sold nearly everywhere these days.  In California, where I live, I can find CBD products sold at grocery stores and fitness gyms.  How is it legal to sell these??

Most of the products that are currently sold are derived from the hemp plant and do not contain THC, the active ingredient in marijuana.  With the pending regulation changes in many states, many companies have focused solely on hemp derived CBD, since this exempts them from some federal regulation. There certainly is still confusion about how exactly CBD is to be regulated.  The FDA is clear that CBD is excluded from the list of dietary supplements.  However, they say that CBD can be sold legally in some cases.  Specifically, companies can not make any medical claims about the product. California is one of several states where CBD can be bought and sold, but it depends on each city.  For example, in Rancho Santa Margarita, CBD is considered marijuana and is restricted.

While the jury is still out about the potential benefits or harms of CBD, there has been a surge in public interest.  Here's a scientific article that shows potential anti-rejection benefits in heart transplants (in rats).  Another peer reviewed article shows that CBD may have some benefits in Parkinson's Disease.  Some of the data they pooled showed no benefit, but it was generally found to be safe.  CBD has been studied in articles ranging from fear reduction (in animals), to fertility (in sea urchins), as well as sleep effects.  Interestingly, this sleep study showed that young healthy volunteers had no sleep disturbance with THC.  But, when THC was combined with CBD, at lower doses, the subjects had less stage 3 sleep.  Despite this, they did better on mental tasks the next day.  It must have been fun to be part of that study!

CBD has been shown to reduce airway inflammation (in rats), involuntary facial dyskinesia (rats again), and inflammation in wounds (rats).  It has been shown to be anti-inflammatory in skin cell cell models for dermatitis (petri dish).  Several other studies linked here and here show potential anti-inflammatory effects on the gut (investigation performed on human cell cultures and surgically removed pathology specimens).

There are too many studies to really comment on here, but the list includes the following:
Oral wound healing
Lung effects in rats
Schizophrenia
Alzheimer's Dementia
Post Ebola Syndrome
Jaw Bone Resorption

Conclusion:
CBD is a very interesting chemical derived from the Cannabis family.  It has many promising potential uses but most of its effects are unknown.  It is currently only approved by the FDA for clinical use in epilepsy.  However, the FDA warns against false and unproven claims for selling it.   It definitely has a lot of scientific evidence of having an anti-inflammatory reaction, at least in the gut.  I didn't find much support for its use in musculoskeletal problems, but many of my patients use and endorse it.

Please share your experiences with CBD.  Has it helped you?  Have you had side effects?  Are there other interesting studies you know of?

PRP, Stem Cells, Etc.

The New York Times, May 13, 2019: “Stem Cell Treatments Flourish With Little Evidence That They Work”

What is the role of biologic treatments in shoulders and elbows?  Doctors and patients alike are interested to know if platelet rich plasma (PRP), bone marrow aspirate stem cells, or adipose derived stem cells can stimulate healing of damaged tissue.  In fact, there is a lot of conflicting data, making it hard to reach a conclusion.  This excellent review article by Dr. Jason Dragoo does a great job analyzing the studies we have to date on the use of biologics in the elbow.  One of the article's conclusions is that PRP is superior to corticosteroid injections for lateral epicondylitis (tennis elbow).  This is not too surprising given that we know tennis elbow is a lack of inflammation and healing.  Previous authors have discouraged the use of steroid injections for tennis elbow.  However, Dragoo goes further and states that PRP can be recommended as a first line treatment given the current literature.  He goes on to say that stem cell treatment can't be definitely recommended due to the lack of data on it.


Comment:  I think it's reasonable to offer PRP to patients with lateral epicondylitis as a primary treatment. It can take months or years to recover from tennis elbow.  Those who are impatient for results may consider PRP as a shortcut to recovery.  However, patients should be aware of the 73% success rate at 1 year.  Furthermore, the treatment is not covered by insurance and the cost can be around $600 per treatment.

GPS Guidance for Shoulder Replacement

The most challenging step of shoulder replacement for surgeons is the preparation of the glenoid.  The Glenoid is the "socket" of the shoulder.  Due to years of degeneration and bone wear, the glenoid can become deformed.  This presents a challenge when trying to implant a new socket for a traditional shoulder replacement or a baseplate for a reverse shoulder replacement. 

Various companies have come up with ways of planning the surgery on a "virtual" computer program.  This is helpful for surgeons, who traditionally rely on visual landmarks at the time of surgery.  Because of soft tissues, bleeding, or tight musculature, it can be hard to be certain that the surgery is following the plan.  Studies have shown improved accuracy when surgeons use custom made guides for this step.  

Here's a recent case I performed.  The patient had significant bone loss to the socket.  Prior to surgery, we obtain a CT scan of the shoulder.  Using this scan, we are able to place the implants in a "virtual" environment.  Using this technology, I am able to determine the proper depth, version, and inclination of the reaming and implant placement. 

An example of the preop planning software appearance.

On the day of surgery, we are able to recreate the plan more accurately since the GPS guides the orientation of our instruments.  There is an array of cameras that receive signals from "trackers" we place on the patient and on our instruments.  Surgeons can use this real-time data to make adjustments to optimize the position of the glenoid component.

The GPS can see the "trackers" (red circles) and give real-time feedback about orientation.

My opinion of this technology is that it is not always necessary, but it can be helpful in challenging cases.  The biggest difference it makes for me is the ability to place longer screws when implanting a reverse total shoulder replacement since the computer shows me the screw trajectory in the bone.  Such long screws may help with getting more solid fixation compared to a shorter screw.  

Here is the postoperative X-ray, showing the placement of the implant.  Note the long screw (arrow).