I’m Sandeep Mannava, an orthopaedic sports medicine surgeon and a volunteer physician for the U.S. Skiing and Snowboarding Assoc. My research focuses on the biology of aging, role of stem cells and other biologic therapies to help recovery from injury and to enhance performance. AMA!


Hi Reddit!

I’m Sandeep Mannava, M.D., Ph.D., an orthopaedic sports medicine surgeon at the University of Rochester Medical Center in Rochester, New York and a volunteer physician for the U.S. Skiing and Snowboarding Association. As an avid skier myself, I enjoy working with some of the world’s best winter athletes. I have traveled to Russia, the Czech Republic, and throughout the United States with U.S. Olympians in the Skiing and Snowboarding disciplines. I provide orthopedic sports medicine event and training medical care for U.S. ski and snowboarding stars – many of whom we are seeing compete at the Olympic Games in South Korea this month.

I’m a fellowship-trained orthopedic surgeon who specializes in sports medicine; arthroscopic surgery of the knee and shoulder; as well as shoulder reconstruction and replacement.

I completed my arthroscopy and sports medicine fellowship training at the prestigious Steadman Clinic and Steadman Philippon Research Institute in Vail, Colorado. While in Vail, I assisted in the treatment of professional and elite athletes from the NFL, NHL, NBA, MLB, and numerous Olympians. I enjoy caring for athletes (and non-athletes) of all ages in my practice in Rochester.

My other passion is medical research – I’m interested in the biology of aging, and additionally how stem cells and other biologic therapies can be used to help people recover from injury and improve the body’s performance. In addition to being a practicing orthopaedic surgeon, I am a clinician scientist who has presented my research findings nationally and internationally.

I’m happy to talk to Reddit followers about snow sports, injury prevention and performance enhancement for athletes, as well as how biologic therapies may soon bring new options for care.

I’ll start answer questions at 12pm ET. AMA!

Thanks for the AMA.

What are the latest evidence based treatments for knee osteoarthritis? Is the evidence for stem-cell treatment robust enough for me to dive in yet?


Currently for knee osteoarthritis, the American Academy of Orthopaedics clinical guidelines have strong evidence for rehabilitation, education, non-steroidal anti-inflammatories (like Motrin, Aleve, etc.) and wellness activities. Non-steroidal anti-inflammatories (NSAIDs) should only be taken if one does not have a contraindication to this medication, such as GI issues such as ulcers; kidney disease, etc. Weight loss has moderate evidence for improving this condition. Oftentimes we also manage knee osteoarthritis with injections such as cortisone (which helps reduce acute inflammation) or viscosupplementation (including hyaluronic acid injections - some of these products include SynviscONE, GelONE, Monovisc, Orthovisc). In terms of stem cell therapy, there is not enough evidence to recommend or not recommend stem cell therapy which in our country is either bone mineral aspirate concentrate or adipose (fat) derived stem cells for the treatment of knee osteoarthritis. There are certain providers who feel that these technologies do improve symptoms of knee osteoarthritis but we are waiting on a more robust publication track record for these types of stem cell therapies. There is some very promising evidence supporting the use of platelet-rich plasma therapy for knee osteoarthritis that is not too advanced. This American Academy of Orthopedic Surgeons (AAOS) symposium earlier this month, "Optimizing Clinical Use of Biologics in Orthopedic Surgery", was intended to bring together basic scientists, clinicians, and government agencies such as the Food and Drug Administration and National Institutes of Health, to assess the current state of the literature and identify areas for translational, collaborative research, basic science research, and clinical research, which includes multi-center, prospective, controlled trials for these regenerative medicine therapies.

Thank you for taking the time to answer questions!

Like a bunch of physically active 30-something's, I've got my share of injuries piling up - small labrum tear, etc etc. I'm not a professional athlete, and these things aren't debilitating injuries, but they take their toll. I think a lot of people live with minor problems like this.

Right now, it seems like the best options for this kind of situation are: a) get injected to reduce inflammation (for me, this provided very temporary relief) and/or b) try your luck with physical therapists, who can range from great to completely unhelpful. Surgery seems like it's suitable only for major problems.

So, my questions are:

1) what do you see as the future course of treatment for smaller injuries in non-athletes?

2) is there something on the horizon that will effectively and broadly reduce scar tissue (by encouraging the body to break it down/replace it with orderly tissue)


this is a question we hear from a lot of our active patients. In sports medicine we hope to keep you active, healthy and enjoying sports through either non-operative or operative treatments. In my experience, smaller injuries can often be managed well with taking adequate rest and recovery days, knowing your limit on a workout day, and focusing on injury prevention/technique. Adjuvants like cortisone are helpful for acute flares. (Adjuvants are supplements or more invasive approaches to managing sports injuries.) A good physical therapy or maintenance plan is often key to staying active longer. I agree that physical therapy can be variable and in order to find a physical therapist that matches your needs, we recommend asking friends and colleagues for recommendations as well as physicians. Oftentimes it's the fit of personality between the patient and the therapist that's most important. Surgical intervention is typically reserved for instances in which the pain or dysfunction is so great it affects your daily living or your ability to do the things you love. For your second question, on the horizon we are hopeful that biological therapies like platelet-rich plasma or stem cell therapies could potentially help treat minor injuries. Right now there is. limited but encouraging data for the use of these emerging therapies for the treatment of orthopedic sports injuries.

Hi I am curious about cellular senescence and senolytics such as dasatinib, quercetin and AP20187 which have been proven to extend the life of mice by up to 35% by clearing out damaged cells and senescent cells that are biological dead weight and not serving a purpose. This also lowers the incidence of cancer in old rats as an additional benefit.


Also interested in the elimination of free radicals and fixing / preventing oxidative damage with superoxide dimutase and catalase. This has also been proven to extend the life of rats by almost 30% and also decreases lifetime cancer risk by a lot.


I am also interested in blood products (plasma) from chronologically young donors as its been proven to repair age related damage and restore neurological function in extremely old rats to the point where they are indistinguishable from young rats in bone density, muscular fitness, cardiovascular fitness, joint health, memory and problem solving.

As a optional question, whats the established minimum age that is ethical to collect blood products from a donor either by free donation or for purchase?


Lastly I am interested in neuroregeneration using anti inflammatory medications such as monteleukast which has been proven to stimulate neuron growth and rejeuvinate old rat brains and restore the ability to form memories and solve problems in very old decrepit rats.


What effect in your professional opinion these have on aging, is there any overlap in biological processes and also as a followup which of the these do you think has the most potential for lifespan/healthspan extension? A ranking would be super and if it turns out wrong 20 years from now I wont hold it against you :)

Another bonus question is do you think that using multiple therapies would have a synergistic effect and be more helpful than the sum of each part? Sort of like aging being a process with multiple parts like a lock and by unlocking and repairing multiple biological processes like tumblers in a padlock may completely reverse the process?

Also thank you for doing this AMA and if you have any secrets up your sleeve I havent already mentioned I would love to hear about any novel research!

I am a computer guy by trade but this is a hobby of mine and I would love your feedback. I've been in two high speed rollovers, two bad motorcycle wrecks, served four years in the army, destroyed my knees and back, broke my neck on a bad skydive jump, and also suffer from brain damage so its an issue close to my heart.



Thank you for your questions! It's clear you've done a lot of research on potential, emerging pre-clinical treatments. Right now in orthopedic sports medicine and regenerative medicine in the United States, we are most focused on platelet-rich plasma therapy and bone mineral aspirate concentrate therapy (stem cell). Currently, the Federal Drug Administration (FDA) only allows for the clinical use of minimally manipulated autologous (your own) tissue for orthopedic regenerative medicine uses. We feel that the clinical application of these two therapies have somewhat outpaced our basic science understanding of how they work. Clinically, platelet-rich plasma has been used effectively to treat knee osteoarthritis, tennis elbow and patellar tendonitis. We have some explanations for why this may be beneficial for these conditions but are not absolutely certain the mechanism by which this therapy improves these conditions. Unfortunately, I am unable to comment on the specific aging studies you have cited but I can tell you that platelet-rich plasma and bone mineral aspirate concentrate are on the forefront of the American Academy of Orthopedic Surgery's agenda for emerging biological therapies. A group of orthopedic physicians just convened for the AAOS "Optimizing Clinical Use of Biologics in Orthopedic Surgery" conference at Stanford University led by program chair Constance Chu, MD. I was one of the presenters. This is literally on the minds of all US orthopaedists as the next frontier of promising treatments. We are working to study these therapies with a well thought out, scientific rationale that remains ethical while continuing to benefit our patients. These procedures, because they use your own tissue and involve minimal manipulation to administer, they have an excellent safety profile. As you have mentioned, aging, body mass index and other medical co-morbidities can influence the quality of the growth factors in stem cells that one's body is able to produce. These are some of the hurdles we are trying to overcome.

Which is more commonly injured, tendons or muscles? Is stretching a part of proper warm up or is it not necessary?

Ligaments seem to take forever to heal. Why do these take longer to heal than muscle or tendons? If this is true..

Is the maximum potential of a muscle forever reduced if it has been torn? Would these new therapies prevent this, possibly by preventing scar tissue build up?

Can scar tissue ever be reverted into healthy tissue?


Muscle strains are very common. These typically refer to actual tearing of the muscle. Depending on the extent of the strain -- minor vs. severe -- it can take varying lengths of time for the muscle to heal and for one to return to full function. Muscles have an excellent blood supply and for this reason they tend to heal without surgical intervention. The vascularity of muscle allows nutrients to be brought via the blood vessels to the injured muscle. The muscle does have some inherent stem cells which can potentially regenerate injured muscle, provided the extent of the muscle damage is not too severe. Tendons and ligaments do not have as good of a blood supply. For this reason, they tend to take longer to heal because it takes longer for nutrients to reattach the structures, or they require surgical intervention to reattach or reconstruct the structures. In particular, stretching is somewhat of a controversial topic scientifically. We recommend that people stay active and healthy and as part of that they should work on cardiovascular fitness, strengthening, as well as flexibility and agility. There are dynamic ways to stretch after an appropriate warm-up, which is thought to potentially prevent injury. The timing and usefulness of stretching has been debated for a long time. As for scar tissue, it can remodel into tissue that very closely mimics native, uninjured tissue. At the most basic science level, we don't necessarily think that scar tissue every fully becomes the same as uninjured tissue. Functionally, this difference is often not noticeable by the individual. I typically recommend a formal physical therapy program with associated home exercise program and a gradual return-to-play protocol for the treatment of muscle strains and sprains that do not warrant surgical intervention. Thanks for your question!

ACL tears used to be career enders for athletes but medical advancements have made the recovery period shorter than a year in some cases.

What are some injuries that are currently considered career enders, but will be relatively easy recoveries in the coming years?


This is a great question - I repair ACLs surgically, oftentimes in athletes and other active individuals. The state of the science for ACL reconstruction has come a long way in both surgical technique as well as post-operative physical therapy and return-to-play protocol (the timing at which one can safely return to sport and perform that activity without putting the previously injured knee that has been reconstructed at risk). At this point the next frontier are multi ligamentous (when you blow out a knee and injure more than one of the knee ligaments in one event -- these would be the ACL, the medial collateral ligament or MCL, the lateral collateral ligament or LCL, the posterior collateral ligament or PCL, and/or the posterior lateral corner or PLC). We're working on improving the surgical approaches to these injuries. There has been some great work in our surgical understanding of anatomy and biomechanics from Dr. Robert LaPrade of the Steadman Clinic in Vail, Colorado and Dr. Lars Engebretsen of University of Oslo Medical School in Norway. These surgeons have innovated in the field to make these once career-ending injuries for which athletes are getting back onto the field of play and performing at an elite level.
More work and innovation in surgical technique, as well as regenerative medicine therapies will continue to improve the outcomes of patients who suffer from these severe knee injuries. We're better at diagnosing injuries and have better surgical techniques now to reconstruct them. One unmet need in this patient population is cartilage damage in the young, active patient population. I'm hopeful that with continued research we will also be able to address cartilage injuries in the young active patient population. That was a cool question, thank you for asking!

I've done a lot of personal research on bone marrow stem cells and PRP injection for improving chondromalacia patellae and osteoarthritis. It seems to me that a major problem is the scaffold--that is, injection is not sufficient for the growth factors and cells to remain in one place to differentiate or to exert a positive paracrine influence. Thus, the best results seem to be in combining PRP or stem cells with surgery. Does this seem to be the case in your own research?

Furthermore, might something like activated PRP or a hydrogel in combination with stem cells be a better non-surgical and non-invasive possibility for providing a scaffold and coaxing these biologics into helping tissues regrow when they are injected into a joint?



Thank you for your interest in PRP and bone marrow stem cells for the treatment of chondromalacia (or cartilage softening) and mild osteoarthritis. Most of us clinicians view osteoarthritis on a spectrum of disease and chondromalacia is an early form of osteoarthritis. You are correct that getting the growth factors or stem cells to hone in on the cartilage is challenging. I can tell you that there is clinical literature to support the use of leukocyte-poor platelet rich plasma (LP-PRP) in the treatment of mild knee osteoarthritis. We know this therapy works clinically. The challenge is figuring out scientifically why this biological therapy works. We have theories that the autologous (or your own growth factors) work on some of the inflamed tissue of the joint lining, like the synovium, to decrease inflammation and thereby decrease pain. There could be anabolic affects that also result in less inflammation and pain in the knee. One of the next frontiers in regenerative medicine will be developing the type of treatment and therapy you have mentioned, an injection that can ‘heal’ cartilage softening or cartilage loss. I am hopeful this type of technology will be possible in the coming years, but currently there is not a product that I know of that is able to regrow cartilage that is commercially available. There are labs that are working toward developing a hydrogel or scaffold technology to address cartilage injury, but these are not commercially available or readily available.

What is the future of herniated lumbar discs? What treatments other than the current surgery are coming? What about ozone?


Hello; I'm sorry, but this is outside of my specialty and expertise. I know that lumbar disc herniation are a very common cause of musculoskeletal pain but I unfortunately cannot give you any insight on emerging treatments for it.

What causes bone in the sinuses and ear canals to grow after repeated exposure to cold water? I’ve suffered from Surfer’s Ear for which I’ve had surgery recently and I’d be interested to learn whether the scientific/medical community has developed any working hypotheses on this matter.


As an orthopedic sports medicine surgeon, I specialize in bone and joint injuries in the extremities, especially shoulder and knee. I would have to refer you to an ear, nose and throat (ENT) head and neck surgeon for help with your issue.

Cell apoptosis causes most of the rapid decline of aging, and it is almost impossible for the body to experience apoptosis when is in an anabolic state. Early studies tried to use steroids to halt the decline of age, but why don’t we just use resistance training?

We know we can make even grandparents anabolic through strength training, so why turn to drugs?


Apotosis is programmed cell death that occurs with aging or remodeling in the developing body. From a clinical perspective, one of the lessons I learned from Dr. J. Richard Steadman of the world-renowned Steadman Clinic in Vail is that keeping patients active, healthy and engaged in sports is the ultimate treatment for aging. Dr. Steadman was ahead of his time when he introduced many principles of early physical therapy and weight training as opposed to immobilization and strict bed rest for the treatment of sports injuries. We are just starting to understand the many benefits of exercise, and weight training, regardless of age and ability level. Exercise, for example, affects the dopamine pain pathway, so we know that people who exercise have a natural euphoria and typically have a better ability to handle pain from a neurological perspective.

Do you administer pregnenolone and/or DHEA to any of your patients/athletes? If so, what are the short term/long term effects you have witnessed using these drugs?


Sorry, I have not used either of those. In general, a well balanced diet coupled with exercise is our recommendation for staying active and healthy. Supplements can be beneficial; however, they are not as tightly regulated by the FDA for content, quality, potency or clinical benefit -- meaning they are not required to have the same level of preclinical and clinical evidence for their use as approved FDA medications.

As I have gotten older I note that I can still run as fast as I did 15-20 years ago and do other athletic activities at a similar level for short periods, but I cannot sustain the necessary training to get back to the same level of, say, a full 5K race time.

The big difference I see in aging isn't, strictly speaking, physical capacity, but it is the ability to recover quickly enough between intense workouts to sustain the necessary training to reach those prior race times, etc.

What do you recommend for improving recovery time between intense workouts for an older athlete? What other advice do you have for an older athlete to get the most out of available effort?


That's a great question! First, I want to give you kudos for staying active. This is a common issue that many of my athletes face as they grow older. Varying a workout routine and cross-training in other complementary activities could potentially improve your ability to run on race days and improve your ability to bounce back after intense running competition. Varying the workout strengthens your entire body, not just the muscles you predominantly use when you run, and will hopefully lead to less running fatigue. Overworking your body will result in you having difficulty bouncing back as quickly as you used to when you were younger. Overtraining is another potential pitfall during athletic participation. Athletes of any age need to be careful that they do not overtrain. By varying the workouts with running, biking, yoga, hiking and other activities are a way of staying active and gaining the benefits of exercise, while hopefully also preventing injury. Make sure you have a well balanced diet and you are adequately fueling the workouts with a balance of protein, carbohydrates and healthy fats as well as staying hydrated.

Hello! I've just got a quick question. So basically I don't usually do sports but decided to go for a 10Km run and since then my right knee has not stopped making cracking sounds. No pain, just slight discomfort until I "pop" it. Do you know what's going on? I'm 17 if that helps.


In young patients, the feeling of cracking and popping in the knee that is not accompanied by pain is often due to something called chondromalacia -- basically, slight softening of the cartilage which is common and normal in most active knees. Or it could be small plicas that can form in the knees -- these are normal synovial or joint-lining folds within the knee. Knees are filled with synovial fluid, so it's not unusual to hear sounds as the knee joint glides. Provided that you have full range of motion and no pain, we recommend continuing being active and healthy.

What are your thoughts about the impact of food allergies in regards to how the impact the body as it ages. I know when I eat foods that I am allergic to I get a delayed immune reaction, usually a couple of days after eating the foods, that affects my elbows and other joints. I wonder what the long term impact is because lately I have fallen off the food allergy cart and have been consuming known allergens on a regular basis.


That's an interesting question - I don't have any direct experience with this, but an allergist/immunologist or rheumatologist would be able to give you advice on the interaction between the body's immune system and joint pain. I have a sense they are related but in Orthopaedics we deal with more structural trauma to the bones, muscles, tendons, ligaments and joints. It's a good question, and if you are having difficulty these would be the people to consult with.

I am over 65 with a broken metatarsal for 90 days that has been lined up and stable but not growing much bone to re-connect the break. Is there anything that I can add to my diet that would likely help it along?


I am sorry to hear about your fracture that is taking some time to heal. I would recommend working with your primary care physician or a metabolic bone specialist to figure out if your vitamin D and calcium levels are low. Further, it may be wise to check for osteoporosis or osteopenia. A primary care physician or a metabolic bone specialist can also test for other abnormalities that could potentially explain why the bone is not healing. Depending on the location of the fracture, sometimes the bone does not have a good blood supply and for that reason it cannot get the nutrients it needs to heal the fracture quickly. Other times, fractures may not heal because of underlying metabolic or hormonal issues that are resulting in a healing response that is not as robust. These are all conditions that can be assessed by a qualified medical professional.

In terms of the best diet for helping a bone heal, we recommend a well-balanced diet. We recommend a diet rich in vitamin D and calcium. Further, since you need your body to produce or make new bone, having enough protein is also helpful.

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