Dr. John Brennan, MD

Orthopedic Surgery
38 procedures 2 hospitals East Setauket, NY
Latest available Medicare data — updated April 2026
Growing Volume

Contact & Location

Phone: 631-689-6698
Practice phone listed in the NPI registry
6 Technology Dr Ste 100
East Setauket, NY 11733
NPI: 1154353977
Credentials: MD
Active Medicare provider (NPI verified)
20 years of practice experience
Licensed MD
Licensed surgical specialist
Board-certified orthopedic surgeon
Contact information available
Find Practice on Google Maps
Knee replacement recovery kit Ice machines, mobility aids, bathroom safety, all under $50
National Comparison by Procedure
Hip 11 vs 36 avg (4,532 surgeons)
Knee 27 vs 45 avg (6,599 surgeons)

Dr. John Brennan is a board-certified orthopedic surgeon practicing in East Setauket, New York. A Medicare provider since 2006, Dr. Brennan has performed 27 Medicare-verified knee replacements (#147 in New York) and 11 hip replacements, for a combined total of 38 procedures.

In New York, Dr. Brennan performs below average in knee (27 vs 47 avg), below average in hip (11 vs 42 avg).

Dr. Brennan's reported Medicare volume is split between knee replacements (27 cases) and hip replacements (11 cases).

Beyond general orthopedic surgery, Dr. Brennan holds additional credentials in Sports Medicine, reflecting subspecialty training that may benefit patients with complex joint conditions.

East Setauket is home to 7 orthopedic surgeons in the current Medicare dataset. Patients in the East Setauket area can compare surgeon volume and procedure specialization to find the right fit for their joint replacement needs.

Medicare records for Dr. Brennan extend back to 2015, covering 10 years of data. Over that period, recorded procedure volume increased from 12 to 38 in the most recent data, a 217% increase. This sustained growth reflects an expanding joint replacement practice.

Dr. Brennan's 27 knee replacement procedures is below the national average of 45 among 6,599 surgeons. Medicare data captures roughly a third of all joint replacements, so actual volume is likely higher.

Verified Medicare Cases

Knee Replacement
27 verified cases
#147 in New York
Hip Replacement
11 verified cases
#195 in New York
Estimated total: 100 – 120 procedures (all insurers)
Based on Medicare FFS representing 33–37% of national joint replacement volume
How is this estimated?

Medicare Part B fee-for-service claims represent approximately 33–37% of all joint replacements performed nationally (source: CMS data, AJRR). This range estimates the surgeon's total practice volume across all payers. The verified Medicare count above is the definitive, audited figure.

How Dr. Brennan Compares

Procedure volume compared to the New York state average.

Hip Below Avg
11 Avg: 42
Knee Below Avg
27 Avg: 47
Dr. Brennan New York Average

Volume Trend Analysis

Dr. Brennan's Medicare-recorded procedure volume has trended upward over 10 years, increasing 217% from 12 procedures in 2015 to 38 in the most recent data.

Years of Data 10
2024 Volume 38
Peak Volume 38 (2024)
Trend Growing

Hospital Affiliations & Quality

H
St Charles Hospital
4/5
Port Jefferson, NY
Similar to national avg
H
Stony Brook University Hospital
4/5
Stony Brook, NY
Better than national avg

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:

Knee Replacement Recovery Overview

Recovery timelines vary by patient, but here is a general overview of what to expect after knee replacement surgery:

Week 1-2 Walking with assistive device. Knee bending exercises begin immediately. Ice therapy and elevation for swelling control.
Week 3-6 Increased range of motion (target 90 degrees). Walking longer distances. Physical therapy intensifies with strengthening exercises.
Week 7-12 Most patients walk without assistive devices. Resume driving and desk work. Continue PT for strength and flexibility.
Month 4-6 Near-full recovery. Resume most recreational activities. Some swelling and stiffness may persist but continues improving.

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. Brennan

How does Dr. Brennan's procedure volume compare to other New York surgeons?

Dr. Brennan has performed 38 Medicare-verified joint replacement procedures. The New York average is 69 procedures per surgeon. Medicare data captures roughly one-third of all joint replacements, so total volume may be higher. Dr. Brennan ranks #202 out of 334 orthopedic surgeons in New York.

What types of joint replacement does Dr. Brennan perform?

Dr. Brennan's Medicare data shows procedures in knee replacement (27 cases) and hip replacement (11 cases).

Are there other orthopedic surgeons near Dr. Brennan in East Setauket?

Yes. There are 7 orthopedic surgeons in East Setauket 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 New York surgeons.

What does the Medicare data for Dr. Brennan represent?

The procedure counts shown are based on the most recent Medicare Part B fee-for-service claims data, published by the Centers for Medicare and Medicaid Services (CMS). This captures approximately 33–37% of all joint replacements performed nationally. Dr. Brennan's total practice volume — including private insurance and Medicare Advantage patients — is likely higher than the 38 procedures shown here.

Has Dr. Brennan's procedure volume changed over time?

Yes. Dr. Brennan's Medicare-recorded volume has increased from 12 procedures in 2015 to 38 in the most recent data, a 217% increase over 10 years. This upward trend suggests an expanding joint replacement practice. Peak volume was 38 procedures in 2024.

Does Dr. Brennan perform more than one type of joint replacement?

Yes. Dr. Brennan's Medicare data shows procedures in knee replacement (27 cases), hip replacement (11 cases). Surgeons who perform multiple joint replacement types maintain broad technical skills across different anatomical joints.

Which hospitals is Dr. Brennan affiliated with?

According to CMS facility affiliation data, Dr. Brennan is affiliated with St Charles Hospital, Stony Brook University Hospital.

How does Dr. Brennan compare to other orthopedic surgeons in East Setauket?

Among the 7 orthopedic surgeons in East Setauket, Dr. Brennan ranks #6 by total Medicare procedure volume. The highest-volume surgeon in East Setauket has 308 verified Medicare procedures.

What are the quality ratings for hospitals where Dr. Brennan practices?

St Charles Hospital (4 out of 5 CMS stars, hip/knee complication rate similar to national average); Stony Brook University Hospital (4 out of 5 CMS stars, hip/knee complication rate better than national average). These are hospital-level quality metrics from CMS Hospital Compare and do not reflect individual surgeon outcomes.

Other Orthopedic Surgeons in East Setauket, New York

Dr. Brennan's 38 Medicare procedures are below the East Setauket average of 121. The table below compares verified procedure volumes for orthopedic surgeons practicing in East Setauket.

SurgeonProceduresSpecialties
Dr. James Nicholson 308 Hip, Knee
Dr. Douglas Petraco 205 Hip, Knee
Dr. Fazel Khan 98 Hip, Knee
Dr. Christopher Mileto 91 Hip, Knee, Shoulder
Dr. Gregory Mallo 80 Shoulder
Dr. Gregory Minutillo 28 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.

Cite This Data

APA: OrthoProcedures. (2026). Dr. John Brennan, MD -- Orthopedic Surgeon Profile. Retrieved from https://orthoprocedures.com/surgeons/ny/dr-john-brennan-east-setauket.html

Link: https://orthoprocedures.com/surgeons/ny/dr-john-brennan-east-setauket.html

Data source: CMS Medicare Part B Provider Utilization & Payment Data. Full methodology | Open Data API

Important: Rankings are based solely on Medicare procedure volume and do not reflect quality of care, patient outcomes, or procedures covered by private insurance. This data represents approximately one-third to 40% of all joint replacement procedures nationwide. Always consult with healthcare providers to make informed decisions about your care.