Ivy League educated and trained, Dr. Diana is proficient in minimally invasive anterior hip replacement, quadriceps sparing computer total knee arthroplastry, computer-navigated knee replacement, and MAKOplasty(R) minimally invasive partial knee resurfacing. Dr. Diana’s expertise in adult reconstructive medicine enables him to customize each patient’s treatment plan to ensure optimum outcomes.

Dr. Diana has performed over 1500 hip replacement surgeries using the anterior hip replacement approach and more than 3500 total knee joint replacement surgeries.

Dr. John DianaPresident of Napa Valley Orthopaedics, Dr. Diana has served as Chairman of Surgery at Queen of the Valley Hospital. He is actively involved in the community through Napa Valley Orthopaedics’ outreach efforts with area athletes, and is a 2x finisher of the Western States Endurance Run.


John N. Diana, M.D. Credentials

Dr. Diana knee treatmentDr. Diana knee x-ray



I was already dealing with severe back and neck pain when my first knee began giving me trouble.It got to the point where it was painful to stand, let alone walk. Dr. Shifflett first used non-operative care which helped greatly with the pain but in time I needed knee replacement. Dr. Shifflett and the staff at the Queen were amazing – walked me through every step of the joint replacement process, and really prepared me for what to expect.

Following surgery, the Queen physical therapy staff had me walking almost immediately, and eventually doing my physical therapy in the pool which I prefer – it’s more fun and you’re weightless! It all went so well, and I recovered so quickly, that when my other knee needed to be done a year later, I had no fears and Dr. Shifflett was right there with me. The same was true the year after that when one of my hips needed to be replaced, again Dr. Shifflett and the Queen guided me through it. And the same will be true when my other hip goes…. And I feel fully prepared!”

Diane Sarant, Napa
Total Knee & Hip Replacement

My right knee had grown worse over the years to the point where I couldn’t kneel down or get up easily. When I first started seeing Dr. Diana, he gave me injections that lessened the pain. After a while the injections stopped working and I knew it was time. Dr. Diana explained how using computer navigation helps him make the most accurate measurements, resulting in successful knee replacement.
I believe Dr. Diana’s surgical skills and then my commitment to post-surgery rehab quickened my recovery. Dr. Diana had me using the CPM machine immediately after surgery and I stuck with it – and am now back to doing all the things that I want to do.”

Angela Pieper, Napa
Computer Navigated Knee Replacement