BACKGROUND: Pain in the heel and Achilles tendon is a common complaint among children between the age of 7 and 12. The condition was first described by Dr. Sever in Boston in 1912 and has been attributed to apophysitis or inflammation of the bone. The treatment has consisted of relative and absolute immobilization using orthotics, cast-boots or casts. Despite treatment, over 50% of children have ongoing or recurrent problems.

HYPOTHESIS: With careful reconsideration of the pathophysiology of the disease, we believe it is caused by a problem in the tendon and a failure of adaptation to increasing loads imposed by rapid growth. Specifically, we have found there is an exponential increase in load on muscles and tendons as children grow. This relationship was the basis of a new theory on the pathophysiology of Duchenne Muscular Dystrophy, published in the journal Muscle & Nerve in September 2013.

CURRENT RESEARCH FINDINGS: We have found that implementation of a very specific 12-week exercise program can result in total resolution of symptoms in as quickly as 2 weeks. By eliminating the use of ineffective orthotics and cast-boots, children are allowed greater mobility during treatment and enjoy a rapid return to sports and physical activities.

54 children have completed the 12-week program. – almost all are experiencing marked resolution or marked improvement in their symptoms, most in the first 2 weeks of treatment. 3 additional participants are currently enrolled; once the study is complete, we will further analyze our data and submit a paper with our findings.

GOAL: The NMRF Research Team is preparing a manuscript for submission to The American Journal of Sports Medicine.

Read the Sept 2019 update, Sever’s Disease Study – Let’s Keep Kids Moving!



BACKGROUND: Under the auspices of Napa Medical Research Foundation, Dr. John Diana, Napa orthopedic surgeon and avid ultra-marathon runner, and Dr. Bodor have been appointed by the organizers of the Western States 100 Mile Race to do research and help further our understanding of orthopedic problems and the effects of running and exercise on the human body.

HYPOTHESIS: During the course of a 100 mile run, the amount of load on the hips and knees are equivalent to what a casual athlete or sedentary person might exert during the course of a year, so this gives us an opportunity to look at changes before and after the race and gain insights into what structural variations might lead to symptoms or a good performance.

Hip Labrum tears are thought to be a risk factor for the development of osteoarthritis. By studying hip labral tears in ultra-marathon runners, we can get more rapid feedback as to what might cause pain and dysfunction in the casual athlete or more sedentary person.

IRB approval for this project has been obtained thanks to Adventist Health/St. Helena Hospital.

Read the March 2018 article, Ultra-Marathoners and The Hip: A Study

Related Studies

Part 1: Bone health in ultramarathon runners (IRB approved)

Completed by Drs. Hoeg, Diana, Bodor and Drs. Emily Kraus and Michael Fredericson at Stanford. This study looked at the prevalence of risk factors for decreased bone mineral density and stress fractures in ultramarathon runners.

61 runners competing in the 2018 Western States 100 Mile Race (20 females, 41 males) were enrolled in the study. Each runner completed an online questionnaire looking at dietary habits, bone stress injury (BSI), and menstrual dysfunction. DXA scans were used to measure the results of each runner’s bone mineral density.

Together, the survey and scans provided key information to researchers about risk factors for decreased bone mineral density based on its prevalence at different body sites. Preliminary results from this study were presented at the American Medical Society for Sports Medicine and the Western States Endurance Run conferences.

GOAL: Final results will be published in a peer-reviewed medical journal.

Part 2: Genetics of bone health in ultramarathon runners

The NMRF team including Dr. Hoeg will continue the study of genetic risk factors for low bone mineral density and stress injuries in ultramarathon runners with the Stanford departments of Orthopedics and Genetics, InsideTracker and AxGen.

This study investigates the relationship between bone health and known genetic risk factors.  51 runners met the enrollment criteria and their data is undergoing statistical analysis at Stanford.

Read the August 2019 article, “Sport & Science Align Among Colleagues”


BACKGROUND: The anterior cruciate ligament (ACL) technique validation study objective is to confirm that using ultrasound as a guide, a needle can accurately inject cells into the ACL. The ACL has been historically very difficult to see using ultrasound and thus very challenging to treat without surgery.  

OVERVIEW: This study was designed with the help of Jay Smith, MD of Mayo Clinic’s Physical Medicine & Rehabilitation/Sports Medicine Department. Cadavers were obtained from UC Davis and delivered to the Napa Medical Research Lab for injection by Dr. Bodor, followed by subsequent section with Dr. Hoeg.

CURRENT RESEARCH FINDINGS: This cadaveric study validated that the ultrasound-guided injection technique used at the Bodor Clinic for delivery of injectate into specific areas of the anterior cruciate ligament (ACL) in the knee is highly accurate. 

GOAL:  We are currently planning a 10-year clinical trial with the UC Davis PM&R and Orthopedics Departments.  In this study, the objective is to heal ruptured ACLs in children and young adults, with our bone marrow aspirate concentrate (BMAC) procedure, to assess long-term outcomes, and to compare them against a controlled group treated with surgical reconstruction.

Read the August 2019 updates, “Improving ACL Treatment”

 Reduce Pain. Increase Mobility & Function. Improve Quality of Life.

All the research conducted through the Napa Medical Research Foundation, a 501(c)(3) nonprofit organization, is fully funded through generous donations received from individuals and family foundations.