Dr. John Diana, M.D.
Contact & Location
707-254-7117
Napa, CA 94558
Dr. Diana performs more knee replacement procedures than 98% of orthopedic surgeons in California, based on 2024 Medicare claims volume.Derived from the state ranking shown on this page: #6 of 491 ranked knee surgeons in California.
About Dr. Diana
Practice. Dr. John Diana is a board-certified orthopedic surgeon practicing in Napa, California. The latest annual CMS data records 207 knee replacements and 122 hip replacements, 329 procedures in all. That is #6 in California for knee replacement. A Medicare provider since 2006.
Trend. Medicare records run from 2013 to 2024, 12 years. Volume rose from 246 procedures a year to 329, up 34%.
National context. Among 6,612 knee replacement surgeons tracked nationally, 207 procedures is more than 4x the national average of 45. That is #54 nationally.
Local context. Napa has 2 orthopedic surgeons in the current Medicare data. Comparing volume and procedure mix across them is one way to narrow a shortlist.
Verified Case Volume Trends (2013-Current)
| Year | Hip Replacement | Knee Replacement |
|---|---|---|
| 2013 | 91 | 155 |
| 2014 | 103 | 187 |
| 2015 | 110 | 216 |
| 2016 | 132 | 206 |
| 2017 | 125 | 204 |
| 2018 | 116 | 254 |
| 2019 | 135 | 254 |
| 2020 | 99 | 199 |
| 2021 | 125 | 220 |
| 2022 | 119 | 199 |
| 2023 | 118 | 208 |
| 2024 | 122 | 207 |
Verified Medicare Cases
How is this estimated?
Medicare Part B fee-for-service claims are one payer stream among several, and the share they represent differs by procedure. In 2024 it was 23% to 28% for knee replacement, 25% to 33% for hip replacement. Each verified count above is divided by its own procedure's range, and the results are added, to estimate total practice volume across all payers. The verified Medicare count is the definitive, audited figure; this is a range derived from published national volume projections, not a measurement, and an individual practice can sit well outside it: how these ranges are derived, and their sources.
How Dr. Diana Compares
Procedure volume compared to the California state average.
Volume Trend Analysis
Dr. Diana's Medicare-recorded procedure volume has trended upward over 12 years, increasing 34% from 246 procedures in 2013 to 329 in the most recent data.
Hospital Affiliations & Quality
Quality ratings and complication rates are hospital-level metrics from CMS Hospital Compare and do not reflect individual surgeon performance. Star ratings updated quarterly. Complication data covers a rolling 3-year period.
Patient Resources: Preparing for Knee Replacement
If you are considering knee replacement surgery, these evidence-based guides can help you prepare and recover:
An overview of current surgical approaches including robotic-assisted and minimally invasive techniques, implant options, and expected outcomes.
What to Expect on the Day of SurgeryA step-by-step walkthrough of your surgical day, from pre-op preparation through anesthesia, the procedure itself, and the first hours of recovery.
Nutrition and Recovery After Joint ReplacementHow protein intake, anti-inflammatory foods, hydration, and targeted supplements support bone healing and tissue repair after surgery.
Medicare Coverage for Joint ReplacementWhat Medicare Part A and Part B cover for joint replacement surgery, including hospital stays, surgeon fees, anesthesia, and physical therapy.
Knee Replacement Recovery Overview
Recovery timelines vary by patient, but here is a general overview of what to expect after knee replacement surgery:
Individual recovery varies based on overall health, age, and adherence to physical therapy. View full knee replacement recovery guide and product recommendations
Frequently Asked Questions About Dr. Diana
How does Dr. Diana's procedure volume compare to other California surgeons?
Dr. Diana has performed 329 Medicare-verified joint replacement procedures. This is more than 4x the California average of 68 procedures per surgeon. Dr. Diana ranks #8 out of 613 orthopedic surgeons in California.
What types of joint replacement does Dr. Diana perform?
Dr. Diana's Medicare data shows procedures in knee replacement (207 cases) and hip replacement (122 cases).
How experienced is Dr. Diana with knee replacement surgery?
Dr. Diana ranks #6 in California for knee replacement with 207 Medicare-verified procedures. This high ranking among 613 state surgeons indicates significant experience with this specific procedure.
Are there other orthopedic surgeons near Dr. Diana in Napa?
Yes. There are 2 orthopedic surgeons in Napa in the current Medicare dataset. Patients can compare procedure volumes and specializations to choose the surgeon who best fits their needs. Use the state page to view all California surgeons.
What does the Medicare data for Dr. Diana represent?
The procedure counts shown are based on 2024 Medicare Part B fee-for-service claims data, published by the Centers for Medicare and Medicaid Services (CMS). Medicare fee-for-service is only one payer stream, and the share of national volume it represents differs by procedure. In 2024 the share was 23% to 28% for knee replacement, 25% to 33% for hip replacement, which puts Dr. Diana's total volume across all insurers at roughly 1,110 to 1,390 procedures against the 329 verified here. Those shares are derived from published national volume projections rather than quoted from a single publication, and they are estimates with real uncertainty. The OrthoProcedures methodology page shows the full derivation, the sources, and the limits at orthoprocedures.com/data-methodology.html.
Has Dr. Diana's procedure volume changed over time?
Yes. Dr. Diana's Medicare-recorded volume has increased from 246 procedures in 2013 to 329 in the most recent data, a 34% increase over 12 years. This upward trend suggests an expanding joint replacement practice. Peak volume was 389 procedures in 2019.
Does Dr. Diana perform more than one type of joint replacement?
Yes. Dr. Diana's Medicare data shows procedures in knee replacement (207 cases), hip replacement (122 cases). Surgeons who perform multiple joint replacement types maintain broad technical skills across different anatomical joints.
Which hospitals is Dr. Diana affiliated with?
According to CMS facility affiliation data, Dr. Diana is affiliated with Adventist Health St Helena, Providence Queen Of The Valley Medical Center, Sonoma Valley Hospital, Adventist Health Clearlake, Adventist Health Ukiah Valley.
What are the quality ratings for hospitals where Dr. Diana practices?
Adventist Health St Helena (4 out of 5 CMS stars, hip/knee complication rate similar to national average); Providence Queen Of The Valley Medical Center (4 out of 5 CMS stars, insufficient case volume for complication rate comparison); Sonoma Valley Hospital (1 out of 5 CMS stars, insufficient case volume for complication rate comparison). These are hospital-level quality metrics from CMS Hospital Compare and do not reflect individual surgeon outcomes.
Other Orthopedic Surgeons in Napa, California
Dr. Diana's 329 Medicare procedures are above the Napa average of 224. The table below compares verified procedure volumes for orthopedic surgeons practicing in Napa.
| Surgeon | Procedures | Specialties |
|---|---|---|
| Dr. Michael Caravelli | 118 | Hip, Knee |
Patient Resources & Verification
Research reviews, verify credentials, and check official quality data through these trusted sources:
Medicare Care Compare and NPI Registry are official U.S. government sources. Google reviews reflect user-submitted feedback. OrthoProcedures.com does not verify the accuracy of third-party review content.