John J. Brennan, MD

Sports Medicine, Joint Replacement


  • Bio & Education

  • Specialties

  • Team

  • Locations

John Brennan, MD, received his medical degree from SUNY Health Science Center at Brooklyn after attending college at St. Louis University. He then performed a surgical internship at St. Luke’s-Roosevelt Hospital Center in Manhattan and followed with his orthopedic residency also at St. Luke’s-Roosevelt Hospital Center. During training, he completed rotations at Alfred I. DuPont Children’s Hospital in Delaware, Memorial Sloan-Kettering Cancer Center as well as The Blackrock Clinic in Dublin, Ireland.

Dr. Brennan is board certified in orthopedic surgery and is a member of the American Association of Hip and Knee Surgeons, Medical Society of the State of New York, Suffolk County Medical Society and the Irish-American Orthopedic Society. He also has an extra board certification in sports medicine from the American Board of Orthopedic Surgery. Dr. Brennan merged his practice with St. Charles Orthopedics after being in practice in Southampton since 1999.

Dr. Brennan’s practice focuses on complete care of the shoulder, hip and knee with a particular emphasis on minimally invasive techniques. His philosophy is to avoid surgery if at all possible but when it is necessary, utilize the fastest, easiest recovery possibly. These techniques include arthroscopic shoulder and knee repairs including rotator cuff and labral tears in the shoulder and meniscus and ACL tears in the knee. When hip and knee replacements are needed, he uses the latest cutting edge technology with small incision techniques.

Rotator Cuff Repair
Labrum Repair
Bone Spurs

Meniscus Tears
Cartilage Tears
Knee Replacement
Partial Knee Replacement
ACL Tears

Hip Replacement


Linda Costello, Key Assistant: This email address is being protected from spambots. You need JavaScript enabled to view it.

Sean O'Came, Physician Assistant: (631) 689-4188


325 Meeting House Lane
Building One
Southampton, NY 11968


74 Commerce Drive
Suite 4
Riverhead, NY 11901

East Setauket

6 Technology Drive
East Setauket, New York 11733

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Office Locations - Blue Surgery Locations: Green Outpatient Rehabilitation Locations: Red