Our Providers

John W. Adkison, MD

John W. Adkison, MD

Dr. Adkison received his undergraduate degree from Whitman College in Walla Walla, WA, and his medical degree from the University of Washington in Seattle. He completed two internships, one in medicine at Harvard University and one in surgery at the University of California in San Diego. He also completed the Orthopaedic Residency Program at the University of California in San Francisco.

Dr. Adkison then completed a Fellowship in Hand Surgery at the University of Edinburgh in Edinburgh, Scotland. He is Board Certified in Orthopaedic Surgery and is a Fellow of the American Academy of Orthopaedic Surgeons.

Dr. Adkison has a Certificate of Added Qualification for Surgery of the Hand. He limits his orthopedic practice to specialty work in the upper extremity.

Michael A. Chang, MD, PhD

Michael A. Chang, MD, PhD

Dr. Chang received his undergraduate degree from New College of Florida and his medical degree at Mayo Medical School at the Mayo Clinic in Rochester, MN, where he also completed the Residency program in Orthopedic Surgery.

Dr. Chang then completed a Spine Surgery Fellowship at the University of California in San Diego. He is Board Certified in Orthopaedic Surgery and is a Fellow of the American Academy of Orthopaedic Surgeons.

Dr. Chang has an orthopedic practice with emphasis on surgeries of the spine, including the neck and lower back. He has a special interest in degenerative conditions of the spine, computer-assisted spine surgery, and minimally invasive spine surgery.

Shyler L. DeMill, DO »

Shyler L. DeMill, DO

Dr. DeMill received his undergraduate degree from Brigham Young University and his medical degree at the Arizona College of Osteopathic Medicine in Glendale, AZ. He completed a five-year residency program in Orthopedic Surgery at Doctor's Hospital and Grant Medical Center in Columbus, OH, through the Ohio University College of Osteopathic Medicine.

Dr. DeMill then completed a Fellowship in Foot and Ankle Surgery at the Orthopedic Foot & Ankle Center in Westerville, OH.

Dr. DeMill treats a wide array of orthopedic problems, but he has special interest in the lower extremity. His practice focuses on foot and ankle sports medicine, reconstruction, arthroplasty, and trauma.

Robert N. Greene, MD »

Robert N. Greene, MD

Dr. Greene received his undergraduate and medical degrees from McGill University in Montreal, Quebec, Canada. His comprehensive surgical internship was completed at Mt. Sinai Hospital in Toronto, Canada.

Dr. Greene then completed his four-year orthopedic residency at the University of Ottawa in Ottawa, Ontario, followed by two years of fellowship subspecialty training for sports medicine and hip and knee replacement surgery. He is Canadian and American Board Certified and a Fellow of the Royal College of Surgeons of Canada and the American Academy of Orthopedic Surgeons.

Dr. Greene has a general orthopedic practice with an emphasis on hip and knee replacement.

Gene L. Griffiths, MD

Gene L. Griffiths, MD

Dr. Griffiths received his undergraduate degree from Brigham Young University and his medical degree from St. Louis University School of Medicine. He completed an internship and residency in Orthopedic Surgery at Tripler Army Medical Center in Honolulu, HI. He also served as a General Medical Officer at Camp Zama, Japan for the U.S. Army.

Dr. Griffiths was employed as an Orthopedic Surgeon at Martin Army Community Hospital, Fort Benning, GA, and at Summit Orthopaedics, Idaho Falls, ID. In addition, he was employed as a General Orthopedist at Central Washington Orthopaedics, Yakima, WA.

Dr. Griffiths is a Diplomate of the American Board of Orthopaedic Surgery. His practice is in general orthopedics, with an emphasis on trauma, sports medicine, and adult reconstructive surgery.

John J. Hwang, MD »

John J. Hwang, MD

Dr. Hwang received his undergraduate degree in Biochemistry from Rutgers University in New Brunswick, NJ, and his medical degree from the Johns Hopkins University School of Medicine in Baltimore, MD. He completed his General Surgery internship and Orthopaedic Surgery residency at the Johns Hopkins Hospital.

Dr. Hwang then completed a Hand Surgery Fellowship program at Barnes-Jewish Hospital in St. Louis.

Dr. Hwang is Board Certified in Orthopaedic Surgery and has a Certificate of Added Qualification in Hand Surgery. He is a Fellow of the American Academy of Orthopaedic Surgeons and of the American Society for Surgery of the Hand. He has an orthopedic practice with an emphasis on hand, wrist, elbow, shoulder problems, arthroscopic surgical treatment for upper extremity problems, and shoulder replacement.

Thomas C. Kennedy, MD

Thomas C. Kennedy, MD

Dr. Kennedy was born and raised in Yakima. He received his undergraduate degree from Stanford University and his medical degree from Washington University. He completed a two-year General Surgery internship followed by four years of Orthopaedic Residency at the University of Minnesota where he also held the position of Assistant Professor in the Sports Medicine section of the Department of Orthopaedic Surgery before deciding to return to Yakima.

He is Board Certified in Orthopaedic Surgery and has a Subspecialty Certificate in Sports Medicine. He is a Fellow of the American Academy of Orthopaedic Surgeons.

Dr. Kennedy specializes in Orthopaedic Sports Medicine, the evaluation and treatment of athletic injuries and conditions of the knee and shoulder including arthroscopic surgery. He also treats arthritic conditions of the knee including performing partial and total knee replacement surgeries.

George S. Liu, MD

George S. Liu, MD

Dr. Liu received his undergraduate degree from Tulane University School of Engineering in New Orleans and his medical degree from Harvard School of Medicine in Boston. He worked as a Postdoctoral Research Fellow at the Harvard Orthopedic Biomechanics Laboratory and then completed the Combined Orthopedic Residency Program at Harvard University. He also served as Chief Resident at The Children's Hospital in Boston.

Dr. Liu is American and Canadian Board Certified and holds active fellowship in the American College of Surgeons, the Royal College of Physicians and Surgeons of Canada, and the American Academy of Orthopedic Surgeons. He served as the Chairman of the Department of Orthopedic Surgery at Yakima Valley Memorial Hospital for 4 consecutive terms and as Chief of Staff at Virginia Mason Memorial Hospital for 2 consecutive terms. He is the current Vice Chair of the Department of Orthopedic Surgery and Medical Staff Officer/Past President at Virginia Mason Memorial Hospital.

Dr. Liu is a general orthopedic surgeon with special interest in shoulder and knee arthroscopic surgery, hip and knee replacement surgery, fracture and trauma surgery, and hand surgery. Dr. Liu emphasizes comprehensive musculoskeletal care for his patients and their families, and also treats various pediatric orthopedic conditions.

Anthony J. Longo, MD

Anthony J. Longo, MD

Dr. Longo received his undergraduate degree in Molecular Biology from the University of Texas at Austin, and his medical degree from the University of Texas Medical Branch at Galveston. He completed his Orthopaedic Residency at the University of Texas Medical Branch in Galveston, Texas.

Dr. Longo has been in practice as an Orthopedic Surgeon in central Washington since 2007.

Dr. Longo is Board Certified by the American Board of Orthopaedic Surgeons. He is a member of the American Academy of Orthopaedic Surgeons and the American Medical Association. He is in practice as a general orthopedic surgeon with an emphasis on sports and total joint replacement of the knee and hip.

Todd B. Orvald, MD

Todd B. Orvald, MD

Dr. Orvald received his undergraduate degree from Duke University in Durham, NC, and his medical degree from Jefferson Medical College in Philadelphia, PA. He completed a surgical internship as well as residencies in General Surgery and Orthopaedic Surgery at Duke University Medical Center. He also completed Pediatric Orthopaedic and Orthopaedic Pathology Fellowships at Duke University Medical Center. He has also served in the United States Army Medical Corps.

Dr. Orvald is Board Certified in Orthopaedic Surgery and is a Fellow of the American Academy of Orthopaedic Surgeons.

Dr. Orvald has a general orthopedic practice with an emphasis on joint replacement surgery.

Richard D. Roux, MD »

Richard D. Roux, MD

Dr. Roux received his undergraduate and Master's degrees from Stanford University in Palo Alto and his medical degree from the University of California at San Diego. He completed the Orthopaedic Residency Program at Harvard University and a Fellowship in Sports Medicine and Arthroscopy at Massachusetts General Hospital/Harvard University. He also completed orthopedic biomechanics research fellowships at UCSD and Beth Israel Hospital/Harvard University.

Dr. Roux is Board Certified in Orthopedic Surgery and holds a Certificate of Added Qualification in Sports Medicine. He is a Fellow of the American Academy of Orthopedic Surgeons and the American College of Sports Medicine. He is the Chief Orthopedic Team Physician for the Central Washington University athletic teams.

Dr. Roux is an orthopedic surgeon who specializes in Sports Medicine, arthroscopic surgery, and treatment of disorders of the knee and shoulder. His treatment goal is to restore maximum function through comprehensive treatment utilizing minimally invasive surgical techniques.

Raymond P. Snyder, MD

Raymond P. Snyder, MD

Dr. Snyder received his undergraduate degree from Washington State University in Pullman and his medical degree from Baylor College of Medicine in Houston. He completed the St. Peter Family Practice Residency Program in Olympia followed by a Fellowship in Sports Medicine at Pacific Sports Medicine in Tacoma.

Dr. Snyder is Board Certified in Family Practice and Sports Medicine. He is a member of the American College of Sports Medicine.

Dr. Snyder's practice involves Sports and Musculoskeletal Medicine including Team Physician functions for local area professional, college and high school teams.

Mark Trump, MD

Mark trump, MD

Medical school: University of British Columbia, Vancouver, B.C.

Residency: Orthopedics, University of Alberta, Edmonton, Alberta, Canada, 2004-2008; orthopedic surgery/emergency medicine, University of Western Ontario, London, Ontario, Canada, 2001-2004.

Fellowship: Orthopedic trauma, Keck School of Medicine of USC, Los Angeles, 2013-2014; sports and arthroplasty, Perth Orthopedic & Sports Medicine Centre, Perth Australia, 2009; upper extremity, Melbourne Orthopedic Group, Melbourne, Australia, 2008.

What inspired you to choose medicine?  I left a career to make a difference to society and my local community. I had a good career working on expedition cruise ships.

Why did you choose your specialty? I enjoy procedural medicine and I enjoy the gratification of surgery. And I particularly enjoy trauma. My entire has been geared toward trauma and sports medicine, since my undergrad days.

What is your philosophy of care? Why I go to work every day is to relieve pain and improve function. That is the motivating force for me, and that’s a fact.

What do you like about Yakima? I’ve been a Pacific Northwesterner since 1992. About Yakima in particular, I like the outdoor environment, the proximity to the mountains.

What do you like to do outside of work? Mountaineering (Swiss Alps, Andes, Canadian and American Rockies, Mount Rainier, Denali and various volcanoes in Indonesia), mountain biking, triathlons, marathons, skiing, sailing and diving.

What do you like about Orthopedics Northwest? The group, the community. The collegiality among the group is what attracted me.

Elizabeth Tikriti, PA-C

Elizabeth Tikriti, PA-C

Education: Master’s degree in Physician Assistant Studies, Western University of Health Sciences, Pomona, Calif.

 

What inspired you to choose medicine?  My patient experiences here in the valley, back when I was a patient growing up.

 

Why did you choose your specialty? I like the flexibility of the profession, and a physician assistant is an integral part of the whole medical picture. It was a good fit for me.

What is your philosophy of care? The patient always comes first, and everything I do should be in their best interest.

 

What do you like about Yakima? I was born and raised here. I like the fact that it’s not a tiny town, but there is a pretty good sense of community.

What do you like to do outside of work? I like to ski, golf and bike. And I also enjoy the local wine and beer scene.

Physician Assistants

Todd Curtis, PA-C

Todd Curtis, PA-C

Todd Curtis received a Bachelor of Science degree in Microbiology from the University of Montana, and a Bachelor of Science degree in Medicine from Western Michigan University.

Todd Curtis is Board Certified by the National Committee for Certification of Physician Assistants, and also holds National Certification in Clinical and Public Health Microbiology. He was a Clinical Microbiologist at Swedish Hospital and Yakima Valley Memorial Hospital, and also worked as a Lab Technician before joining ONW. He primarily assists Dr. Richard Roux in his practice.

Betsy Kean, PA-C

Betsy Kean, PA-C

Betsy Kean received her Bachelor of Arts degree from Central Washington University. She received her Master of Physician Assistant Studies degree and Physician Assistant certificate from Idaho State University in Pocatello, ID.

Betsy Kean is Board Certified by the National Commission on Certification of Physician Assistants, and is a Fellow of the American Academy of Physician Assistants. She also currently holds a Certificate of Added Qualification in Psychiatry through the NCCPA, and has worked with the under served mental health population before joining ONW. She primarily assists Dr. John Adkison in his practice.

Mary Murphy, PA-C

Mary Murphy, PA-C

Awaiting biography.

Tracy Keniston, PA-C

Tracy Keniston, PA-C

Tracy Keniston received her Bachelor of Science degree from Gonzaga University and her Master of Medical Science degree from Midwestern University in Glendale, AZ.

Tracy Keniston is Board Certified by the National Commission on Certification of Physician Assistants, and is a Fellow of the American Academy of Physician Assistants. She primarily assists Dr. Robert Greene with his orthopedic practice, which includes general orthopedics with an emphasis on hip and knee replacement.

Luis Ortega, PA-C, RT(R)

Luis Ortega, PA-C, RT(R)

Luis Ortega received his radiology technologist degree from Yakima Valley Community College and his physician assistant training at the University of Washington. He also has work experience as an X-ray and CT technologist, during which time he was exposed to numerous orthopedic conditions.

Luis Ortega is Board Certified by the National Commission on Certification of Physician Assistants, and is a Registered Radiologic Technologist. He primarily assists Dr. John Hwang with his orthopedic practice. His goal is to provide Yakima Valley residents with appropriate, compassionate care.

Amy Pollock, PA-C, RT(R)

Amy Pollock, PA-C, RT(R)

Amy Pollock received her radiology technologist (RT) degree from Yakima Valley Community College. After 12 years of working as an RT she pursued her dream of becoming a PA-C. She attended the University of Washington Medex Physician Assistant Program and obtained her Bachelor of Clinical Health Sciences degree.

Amy Pollock is Board Certified by the National Commission on Certification of Physician Assistants, and is a Fellow of the American Academy of Physician Assistants. She also is a member of the Washington Academy of Physician Assistants. Amy primarily assists Dr. Gene Griffiths with his orthopedic practice.

Shane Sigler, PA-C

Shane Sigler, PA-C

Shane Sigler attended Whittier College in southern California and received his Bachelor of Arts degree from the University of Puget Sound. He worked as a Certified Athletic Trainer at the high school, college, and professional sports levels. He then received his Bachelor of Clinical Health Sciences degree from the University of Washington Medex Physician Assistant program.

Shane Sigler is a Board-Certified Physician Assistant who works primarily with Dr. Thomas Kennedy in his orthopedic practice, treating conditions of both the knee and shoulder as well as general orthopedic conditions. He also is an active member of the White Pass Volunteer Ski Patrol.

Kevin Walkenhauer, PA-C

Kevin Walkenhauer, PA-C

Kevin Walkenhauer received his Bachelor of Arts degree in Biology from Central Washington University. He earned a Master's degree in Physician Assistant Studies from A.T. Still University in Mesa, AZ. He worked in physical therapy before doing his PA training.

Kevin Walkenhauer is Board Certified by the National Commission on Certification of Physician Assistants, and is a Fellow of the American Academy of Physician Assistants. He primarily assists Dr. DeMill with his orthopedic practice.

Back To Top