Hand & Wrist
A Bergen County native, Dr. Diamond studied Health and Exercise Sciences through the Honors Program at The College of New Jersey before earning his medical degree from Rutgers Robert Wood Johnson Medical School. He completed his Orthopaedic Surgery residency at Maimonides Medical Center in Brooklyn, where he was actively involved in clinical research and authored numerous peer-reviewed research articles. His work earned him the Adrian Flatt Residents and Fellows Scholarship from the American Society for Surgery of the Hand, and he was invited to discuss his research on SiriusXM’s Doctor Radio.
Dr. Diamond completed advanced fellowship training in Hand and Upper Extremity Surgery at the University of Chicago, where he trained under some of the world’s leading hand and upper extremity surgeons. There, he gained extensive experience treating complex trauma, sports injuries, and chronic conditions affecting the upper extremity, caring for patients ranging from young and older adults to amateur and professional athletes.
In addition to hand and upper extremity care, Dr. Diamond treats fractures and a variety of hip, knee, and ankle conditions. He is committed to providing thoughtful, individualized care and is known for his warm manner and dedication to helping patients achieve the best possible outcome.
Dr. Jeffrey Van Gelderen is a Board-Certified Orthopaedic Surgeon at Orthocenter, specializing in sports injuries and minimally invasive arthroscopic surgery of the shoulder, hip, and knee. His expertise is in joint preservation—helping patients stay active, preserve mobility, and postpone joint replacement through advanced, motion-preserving techniques.
A Monmouth County native and graduate of Holmdel High School, Dr. Van Gelderen earned his undergraduate degree magna cum laude from Georgetown University. He received his medical degree from the University of Medicine and Dentistry of New Jersey, completed his orthopaedic residency at NYU’s Hospital for Joint Diseases, and completed a Sports Medicine Fellowship at UCLA, where he served as assistant team physician for NCAA Division I athletes.
For more than a decade, Dr. Van Gelderen has delivered expert orthopaedic care in the community he proudly calls home. He has consistently been named one of New Jersey’s Top Doctors, maintains a 4.9 star rating from over 400 Google reviews, and sponsors an annual health sciences scholarship to support the next generation of medical professionals.
Dr. Tennen received his undergraduate degree in Biology with minors in Mathematics and Chemistry from Ramapo College of New Jersey, graduating with Honors. Following graduation, Dr. Tennen went on to Ross University School of Medicine for his Medical Degree. After receiving his Medical Degree Dr. Tennen completed an Internal Medicine Internship at Elmhurst Hospital in affiliation with Mount Sinai Hospital.
After his Internship, Dr. Tennen completed his Residency in Family Medicine from the Robert Wood Johnson University Hospital in Somerset NJ. After Residency, Dr. Tennen completed an ACGME Accredited Fellowship at Atlantic Sports Health in Morristown NJ. While in Fellowship, Dr. Tennen’s training involved providing sideline medical coverage for the New York Jets, Division I athletes from Seton Hall University and a private hockey league.
Dr. Tennen practices non-surgical techniques, using conservative measures to allow patients to rehabilitate from their injuries. His Primary Care background allows for treatment of Non-Orthopaedic / medical injuries in athletes ranging from concussion management/return to play, athletic fatigue, overtraining, exercised induced asthma, as well as management of athletes with other chronic medical conditions. Dr. Tennen believes in using the patient-centered approach in providing care and building a strong rapport with his patients.
Dr. Tennen is a New Jersey native who was raised nearby in Marlboro NJ. He enjoys spending time with his family, watching football and following the fitness industry. Dr. Tennen plays an active role in his community serving as the District Physician for several local school districts in Monmouth County NJ.
Dr. Tennen was voted one of “America’s Top Doctors”
Dr. Lisser earned his Medical Degree and completed his Orthopaedic Surgery Residency at the Mount Sinai School of Medicine in New York City. He then completed a Hand, Elbow and Microsurgery Fellowship at Thomas Jefferson University in Philadelphia. After that, Dr. Lisser completed a Shoulder Surgery Fellowship at the University of Pennsylvania.
Dr. Lisser is Board Certified in Orthopaedic Surgery by the American Board of Orthopaedic Surgery. He holds additional certifications in Hand Surgery and Sports Medicine. Dr. Lisser is a Member of the American Academy of Orthopaedic Surgery and American Society for Surgery of the Hand.
Dr. Lisser serves as the Chairman of the Department of Orthopaedic Surgery at Hackensack Meridian Riverview Medical Center in Red Bank, NJ and is a past President of the Medical Staff and past member of the Riverview Medical Center Foundation Board.
Dr. Lisser serves on the Board of the Hackensack Meridian Health Hospital Corporation and Chairs the Board’s Medical Council. He also serves on the Board of Directors of the Shrewsbury Surgical Center and is a consultant for medical device companies.
Prior to joining Orthocenter Dr. Friedel boasted an impressive 19-year career as an Orthopaedic Surgeon in the United States Army.
Dr. Friedel completed his undergraduate degree at the United States Military Academy at West Point. Following graduation, he then studied at Uniformed Services University School of Medicine in Bethesda, MD where he earned his Medical Degree.
After receiving his Medical Degree, Dr. Friedel completed his Orthopaedic Surgery Residency at Fitzsimons Army Medical Center in Aurora, Colorado.
Dr. Friedel’s work as an Army Surgeon has been well decorated. During his military career, Dr. Friedel received an array of awards, including the Bronze Star, the National Defense Medal, the Kuwait Liberation Medal, the Army Achievement Medal with Oak Leaf Cluster, the Asian Campaign Ribbon with two Oak Leaf Clusters, and the Combat Medic Badge.