YOUR Orthopedic Surgeon in Naples, FL

Mark A. Klaassen, M.D., F.A.C.S.

Orthopedic Surgeon Mark Klaassen learned early on what caring for others is all about. The son of missionaries, he grew up in Colombia where the positive impact of helping others was tightly woven into his character. This childhood experience made him fluent in Spanish. He returned home to the U.S. as a 15-year-old to continue his education, culminating in the MD degree he earned from the Indiana University School of Medicine at Notre Dame and the I.U. Medical Center. He completed his orthopedic surgery residency at Lutheran Hospital of Indiana and is a Fellow of the American College of Surgeons and the American Academy of Orthopaedic Surgeons. Dr. Klaassen is an active member of the American Association of Hip and Knee Surgeons.

My Mission

“I Want To Score An A+ With All Of My Patients”

Meet Dr. Klaassen

Dr. Klaassen’s areas of specialized expertise include knee, hip and shoulder total joint replacement, and arthroscopic surgery. He currently serves as Professor of Practice in the College of Sciences at the University of Notre Dame. Dr. Klaassen is a consultant and Developer for Biomet, OrthoSensor and Iconacy.

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Mark A. Klaassen, M.D.


I just wanted to take an opportunity to thank you greatly for the service you provided for me. It has been amazing the improvement I am experiencing. A while back before I knew it was a hip problem I guess I felt it was all the aging process and I was wondering with the deterioration in my abilities etc how I would be in another 5 years.

- Total Knee Patient

I have been very active my entire life. A couple of years ago I started having problems with my knee. I live about an hours away from Dr. Klaassen’s office and did not know much about him. When I started to ask around who I should see, I was surprised to hear the recommendation for Dr. Klaassen. Everyone was right.

- Total Hip Patient

The surgeon, Dr. Mark Klaassen, did a marvelous job on my partial knee (right). After 6 weeks what a positive difference in pain. Much less pain. The staff were terrific and very helpful as well as knowledgeable. OSMC is a fabulous place to have your knee surgery done. “All these medical people care about patients here”and all of them have PATIENCE with us ornery PATIENTS. Thank you Dr. Klaassen and thank you team!


I know I can trust Dr. Klaassen and his team to make the best decisions for my health needs. This is the fourth replacement he has done for me and I am pleased with them all.


I felt very comfortable asking the doctor anything especially of expectations afterwards.


The further I went through recovery, the more I cane to appreciate the caring of the surgical staff





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