#123 in New York
Knee

Dr. John Brennan, MD

Orthopedic Surgery
32 procedures 2 hospitals East Setauket, NY
Latest available Medicare data — updated April 2026
Rising Star
Knee replacement recovery kit Ice machines, mobility aids, bathroom safety — under $50 essentials
National Comparison by Procedure
Knee 32 vs 45 avg (6,720 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 32 Medicare-verified knee replacements, ranking #123 in New York.

In New York, Dr. Brennan performs below average in knee (32 vs 45 avg).

Dr. Brennan's Medicare data shows a focused knee replacement practice with 32 verified procedures. Surgeons who concentrate on a single procedure type often develop deep procedural expertise, though total practice volume may include additional procedures not captured in Medicare fee-for-service data.

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 6 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 9 years of data. Over that period, recorded procedure volume increased from 12 to 32 in the most recent data, a 167% increase. This sustained growth reflects an expanding joint replacement practice.

Dr. Brennan's 32 knee replacement procedures is below the national average of 45 among 6,720 surgeons. Medicare data captures roughly a third of all joint replacements, so actual volume is likely higher.

Verified Medicare Cases

Knee Replacement
32 verified cases
#123 in New York
Estimated total: 90 – 100 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.

Knee Below Avg
32 Avg: 45
Dr. Brennan New York Average

Contact & Location

Phone: 631-689-6698
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

Volume Trend Analysis

Dr. Brennan's Medicare-recorded procedure volume has trended upward over 9 years, increasing 167% from 12 procedures in 2015 to 32 in the most recent data.

Years of Data 9
2023 Volume 32
Peak Volume 37 (2019)
Trend Growing

Hospital Affiliations & Quality

H
St Charles Hospital
★★★★☆
Port Jefferson, NY
Similar to national avg
H
Stony Brook University Hospital
★★★★☆
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.

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 32 Medicare-verified joint replacement procedures. The New York average is 67 procedures per surgeon. Medicare data captures roughly one-third of all joint replacements, so total volume may be higher. Dr. Brennan ranks #210 out of 338 orthopedic surgeons in New York.

What types of joint replacement does Dr. Brennan perform?

Dr. Brennan's reported Medicare volume is focused on knee replacement, with 32 verified procedures. Some surgeons choose to concentrate on a single joint type to build deep procedural expertise.

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

Yes. There are 6 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 32 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 32 in the most recent data, a 167% increase over 9 years. This upward trend suggests an expanding joint replacement practice. Peak volume was 37 procedures in 2019.

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 6 orthopedic surgeons in East Setauket, Dr. Brennan ranks #6 by total Medicare procedure volume. The highest-volume surgeon in East Setauket has 292 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 32 Medicare procedures are below the East Setauket average of 126. The table below compares verified procedure volumes for orthopedic surgeons practicing in East Setauket.

SurgeonProceduresSpecialties
Dr. James Nicholson 292 Hip, Knee
Dr. Douglas Petraco 182 Hip, Knee
Dr. Fazel Khan 95 Hip, Knee
Dr. Christopher Mileto 93 Hip, Knee, Shoulder
Dr. Gregory Mallo 61 Shoulder

Patient Reviews & Ratings

OrthoProcedures.com focuses on verified Medicare procedure data. For patient reviews, ratings, and appointment scheduling, visit these trusted platforms:

These links lead to third-party websites. OrthoProcedures.com is not affiliated with these platforms and cannot verify the accuracy of reviews.

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.