Summary

Dr. Leonard “Tiger” Onsen, MD is a dedicated orthopedic surgeon at OrthoIllinois, providing comprehensive care to patients through OSF HealthCare. His journey into orthopedic medicine was inspired by personal experiences with sports-related injuries during his high school years. These encounters with lengthy treatments and surgical recovery gave him firsthand appreciation for the profound impact physicians can have on restoring a patient’s quality of life and enabling them to return to the activities they love.

Dr. Onsen graduated Cum Laude from Illinois Wesleyan University in Bloomington. He earned his medical degree from The University of Illinois College of Medicine at Chicago, where he also completed his residency training in orthopedic surgery. During his residency, Dr. Onsen developed a passion for sports medicine—a specialty that not only allowed him to address a wide range of musculoskeletal conditions but also resonated with his lifelong love of sports and his desire to work with athletes. To further his expertise, he pursued advanced fellowship training in Sports Medicine at Cedars Sinai Kerlan Jose Institute.

In his OrthoIllinois practice through OSF Medical Group, Dr. Onsen specializes in surgery of the knee, shoulder, and elbow. His clinical focus includes ligament reconstructions, tendon repairs, and cartilage procedures. He is committed to helping athletes return to their sport and all patients regain functional and active lifestyles.

Dr. Onsen believes in fostering a comfortable and collaborative environment where patients can make informed decisions about their care. He emphasizes education, advocacy, and mutual respect, ensuring that each patient leaves his office with a clear understanding of their condition, available treatment options, and a strong sense of partnership in their treatment and recovery journey.

Outside of his medical practice, Dr. Onsen enjoys spending time with his wife and young son, exploring new restaurants, and attending movies. He is an enthusiastic supporter of the Chicago Bears, Cubs, Bulls, and Blackhawks, and makes it a point to follow their games and highlights whenever possible.

Read More Read less

Office Locations

Dr. Leonard T Onsen has 4 locations

OSF Medical Group

1050 E Norris Dr Ste 3AOttawa, IL 61350

OSF Medical Group - Mendota

1405 E 12th St Ste 700Mendota, IL 61342

OSF Medical Group

920 West St Ste 221Peru, IL 61354

Quick Facts

  • accepting new patients
  • 8 years of experience
  • 1 insurance plan accepted
  • speaks English
  • University of Illinois College of Medicine at Rockford
  • 2 specialties
  • 2 areas of expertise
  • 3 hospital affiliations
  • 4 office locations
  • Male

Insurance Plans Accepted by Dr. Leonard T Onsen

  • Accepts Medicare
  • Accepts Medicaid
  • Most insurance plans accepted. We highly encourage you to contact your insurance provider at the phone number on the back of your card to verify OrthoIllinois is in-network for your plan.

Medical Specialties

Dr. Leonard T Onsen has the following 2 specialties

Specialty Expertise

Dr. Leonard T Onsen has the following 2 areas of expertise

  • Orthopedic Sports Medicine
  • Sports Medicine (orthopedic Surgery)

Certifications, License, & Education

8 Years Experience

MEDICAL LICENSE

Medical Doctor, Illinois, 2026, Active
Medical Doctor, California, 2025, Inactive

EDUCATION & TRAINING

Medical School

University of Illinois College of Medicine at RockfordGraduated in 2018

Frequently Asked Questions

What languages does Dr. Leonard Onsen speak?
Dr. Leonard Onsen speaks English.
How can I make an appointment with Dr. Leonard Onsen?
You can find contact information for Dr. Leonard Onsen here on Vitals.
Does Dr. Leonard Onsen accept virtual/telehealth appointments?
Dr. Leonard Onsen has not indicated that they accept virtual/teleheatlh appointments. Contact their office through their Vitals profile to check for availability.
Where is Dr. Leonard Onsen's office located?
Dr. Leonard Onsen's office is located at 1050 E Norris Dr Ste 3A, Ottawa, IL, 61350.
Does Dr. Leonard Onsen accept my insurance?
You can see the insurance plans that Dr. Leonard Onsen accepts on their Vitals profile.

Ensuring Data Transparency and Trust: A Guide to Vitals Doctor Listings and Reviews

Our provider data is gathered directly from physicians and publicly available databases. Providers who verify their profiles gain the ability to update information, offering additional details about their specialties,education, treated conditions, performed procedures, and accepted insurances.

Reviews on Vitals are submitted by users only. Recognizing the valuable insights these reviews offer into a doctor's reputation, we maintain internal policies and protocols to ensure the quality and accuracy of all reviews. Importantly, providers cannot delete or alter reviews independently. Reviews can only be deleted or changed following an internal assessment by our customer service team.

Your feedback is highly valued and we encourage you to contact our support team should you encounter any issues.