The team at California Orthopaedic Specilist

David S. Gazzaniga, M.D.

Board Certified Orthopaedic Surgeon – Shoulder, Hip & Knee

Dr. Gazzaniga trained at Dartmouth and completed his residency at Harvard Combined Orthopaedic Residency. He served as Head Team Physician for the LA Chargers (7 years) and the NY Islanders, and is recognized as one of Orange County's leading surgeons in cartilage restoration and joint preservation.

Dr. Ralph J. Venuto

Medical Director

Michael Walker, P.A.

Physician Assistant (Dr. Mikulak & Dr. Rose's PA)

Michael Walker is a Physician Assistant who assists in surgery and sees patients in the office. He holds an M.S. from Western University and began his medical career as an EMT. He is a published ethnobotanist and recipient of the Rachel Carson Scholarship for Conservation Biology.

Michael Weinstein, M.D.

Board Certified Orthopaedic Surgeon – Spine & Sports Medicine

Dr. Weinstein is a nationally recognized specialist in spinal disorders and sports medicine. He completed a fellowship in orthopaedic spine surgery at the Wiltse Spine Institute and has been in private practice since 1987, with a focus on neck, back, shoulder, and knee conditions.

Nicholas Rose, M.D.

Board Certified Orthopaedic Surgeon – Hand, Wrist, Elbow & Shoulder

Dr. Rose specializes in hand, wrist, elbow, and shoulder surgery. He completed a fellowship in Hand, Upper Extremity & Microvascular Surgery at the University of Texas Health Science Center and is known for his superior diagnostic, surgical, and rehabilitative skills.

ralph-j-venuto (Medical Director)

Ralph Venuto, M.D.

Board Certified Orthopaedic Surgeon – Knee & Shoulder

Dr. Venuto has practiced orthopedics for over 45 years, specializing in knee and shoulder disorders including arthroscopy and ligament reconstruction. He served as Chief Medical Officer for wrestling at the 1984 Olympic Games in Los Angeles and has treated top professional, Olympic, and college-level athletes.

Scott Forman, M.D.

Board Certified Orthopaedic Surgeon – Foot, Ankle, Knee & Shoulder

Dr. Forman is a board-certified orthopaedic surgeon with particular expertise in foot, ankle, knee, and shoulder conditions. He trained at UCLA and is well regarded by patients for his surgical skills and well-managed practice.

Stephen Mikulak, M.D.

Board Certified Orthopaedic Surgeon – Hip & Knee

Dr. Mikulak specializes in hip and knee reconstruction and replacement. He is known for his close relationship with Hoag Hospital, making surgery coordination seamless, and for his strong patient-centered communication approach.

Theodore Gregorius, M.D.

Board Certified Orthopaedic Surgeon – Shoulder, Hip & Knee

Dr. Gregorius specializes in arthroscopic surgery of the shoulder, elbow, hip, and knee. He has provided team coverage to the UC Riverside Athletic Department, the Dodgers single-A affiliate, the San Francisco 49ers, and Stanford Football. He completed his fellowship at Stanford University/SOAR.