Dr. Gregory Northrop, M.D.
Contact & Location
626-797-2002
Pasadena, CA 91107
Dr. Northrop performs more knee replacement procedures than 2% of orthopedic surgeons in California, based on 2024 Medicare claims volume.Derived from the state ranking shown on this page: #479 of 491 ranked knee surgeons in California.
About Dr. Northrop
Practice. Dr. Gregory Northrop is an orthopedic surgeon practicing in Pasadena, California. The latest annual CMS data records 12 knee replacements. That is #479 in California for knee replacement. A Medicare provider since 2005.
Trend. Medicare records run from 2013 to 2024, 8 years. Volume has held between 11 and 16 procedures a year.
National context. Among 6,612 knee replacement surgeons tracked nationally, 12 procedures is below the national average of 45. Medicare covers part of all joint replacements, so true volume is likely higher.
Local context. Pasadena has 10 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 | Knee Replacement |
|---|---|
| 2013 | 13 |
| 2014 | 0 |
| 2015 | 12 |
| 2016 | 0 |
| 2017 | 11 |
| 2018 | 16 |
| 2019 | 12 |
| 2020 | 0 |
| 2021 | 15 |
| 2022 | 0 |
| 2023 | 14 |
| 2024 | 12 |
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. 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. Northrop Compares
Procedure volume compared to the California state average.
Volume Trend Analysis
Dr. Northrop's procedure volume has been consistent across 8 years of Medicare data, ranging from 11 to 16 procedures per year. This stability suggests a well-established joint replacement practice.
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.
Home Safety: Creating Your Recovery SanctuaryRoom-by-room modifications, equipment recommendations, and fall-prevention strategies to prepare your home for a safe post-surgical recovery.
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. Northrop
How does Dr. Northrop's procedure volume compare to other California surgeons?
Dr. Northrop has performed 12 Medicare-verified joint replacement procedures. The California average is 68 procedures per surgeon. Medicare data captures roughly one-third of all joint replacements, so total volume may be higher. Dr. Northrop ranks #592 out of 613 orthopedic surgeons in California.
What types of joint replacement does Dr. Northrop perform?
Dr. Northrop's reported Medicare volume is focused on knee replacement, with 12 verified procedures. Some surgeons choose to concentrate on a single joint type to build deep procedural expertise.
Are there other orthopedic surgeons near Dr. Northrop in Pasadena?
Yes. There are 10 orthopedic surgeons in Pasadena 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. Northrop 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, which puts Dr. Northrop's total volume across all insurers at roughly 40 to 50 procedures against the 12 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. Northrop's procedure volume changed over time?
Dr. Northrop's procedure volume has been relatively stable over 8 years of Medicare data, ranging from 11 to 16 procedures per year between 2013 and 2024. Consistent volume over multiple years reflects a steady joint replacement practice.
Which hospitals is Dr. Northrop affiliated with?
According to CMS facility affiliation data, Dr. Northrop is affiliated with Huntington Hospital.
How does Dr. Northrop compare to other orthopedic surgeons in Pasadena?
Among the 10 orthopedic surgeons in Pasadena, Dr. Northrop ranks #10 by total Medicare procedure volume. The highest-volume surgeon in Pasadena has 253 verified Medicare procedures.
What are the quality ratings for hospitals where Dr. Northrop practices?
Huntington Hospital (2 out of 5 CMS stars, hip/knee complication rate similar to national average). These are hospital-level quality metrics from CMS Hospital Compare and do not reflect individual surgeon outcomes.
Other Orthopedic Surgeons in Pasadena, California
Dr. Northrop's 12 Medicare procedures are below the Pasadena average of 94. The table below compares verified procedure volumes for orthopedic surgeons practicing in Pasadena.
| Surgeon | Procedures | Specialties |
|---|---|---|
| Dr. Todd Dietrick | 253 | Hip, Knee |
| Dr. James O'dowd | 108 | Hip, Knee |
| Dr. Micah Berry | 104 | Hip, Knee, Shoulder |
| Dr. John Itamura | 74 | Shoulder |
| Dr. Timothy Jackson | 64 | Hip |
| Dr. Daniel Laster | 46 | 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.