Bike Modifications for the Patient with Arthritic Knee Stiffness


Steve Mora MD
Orange County Knee Specialist 

Patients with a stiff knee have a difficult time cycling because they cannot get their knee to bend enough to properly pedal. In most cases a stiff knee is due to arthritis. These patients have to exercise to help them with their arthritis. However the arthritic knee pain makes it very hard to consistently and effectively exercise without making the pain worse. Running is usually out of the question. Patients with knee arthritis sometimes have to think out of the box to help them stay physically fit. Alternative ways to exercise need to be considered.

I personally suffer from advanced knee pain. I cannot run due to pain which will occur after a couple of miles. My arthritis stems from a childhood car accident. One of my knees was crushed. It has since developed arthritis which makes it very stiff. I cannot bend my knee beyond 80 degrees. I have bone on bone arthritis.

In order to maintain my knee function I have to stay at an optimal weight and condition. In the future I’ll share other highly effective treatments for arthritic knee pain. For this post I will focus on cycling.

I have found that mountain biking  helps me achieve my goals of staying fit, healthy, and at an ideal body weight. By making a few modifications on my bike, I’m able to successfully ride and get a great work out.

First I have a seat post that can be easily raised or lowered by simply pressing a button on my handlebars. This item is called a dropper post. This allows my seat to be instantaneously raised when I have to pedal hard such as going up a hill. When my seat is high my knee is able to get the pedal to make a full revolution without having to bend very much. If I’m going downhill and need to lower my center of gravity, by quickly lowering seat post without having to get off my bike. If I didn’t have the dropper post it would not only inconvenient but also a little unsafe. Going downhill with your seat at a high position can lead to falls. Having to manually raise and drop the post is inconvenient and wastes time. The dropper post helps.

The most impactful modification I’ve made on my bike is a pedal modification. I moved my pedal a bit closer to the center of rotation thereby allowing me to make a full pedal revolution without having to bend my knee like other people. This was done by having a machinist drill and tap a new hole on the crank stem. Please see the attached pic showing the normal and the modified pedal. The side with the pedal modification allows my knee to make a full revolution without bending more than 80 degrees. You’ll have to find a local machinist to make this modification. The best news is that you do not need to buy an expensive custom crank to achieve the same result.

Without an elevated seat post and modified pedal I would not be able to effectively ride. I’m not the most elegant rider but I can get the job done. Its also a lot of fun. I am happy to have an exercise that burns calories, maintains strength, and keeps me fit. All this is good for my knees. Riding can be good for anyone with arthritis.

The reason I’m writing about this is because I feel that these tips are worth sharing for patients who also suffer from arthritic knee stiffness and who’ve been told they have to exercise. Staying at an ideal body weight is very important for these patients. In addition to minimizing undue force on the degenerative joint, it’s also important to keep the muscles around the knee and gluteus area strong.  Whether you prefer cycling, yoga or swimming it is important to have an exercise that can achieve multiple goals.

Exercising with arthritic knee pain is not easy. It’s challenging. You have to think outside the box. The benefits are not only gratifying but also necessary. Just because it is hard it doesn’t mean it cannot be achieved. Do whatever it takes to keep what you have.

I hope the above tips help. If you need help please let me know. I know a lot about arthritic knee pain. I live with it every day. I know what helps and what doesn’t. I know what my patients are experiencing. I’ve also had most procedures done on me which I perform on my own patients. My goal is to keep the function I have and not have a knee replacement. Most of my patients want the same.

Current bike with pedal modification and dropper post.
Local ride in Orange Santiago Oaks
Dr. Mora in Mammoth

About Steve A. Mora MD:

Dr. Mora is a native of Orange County. He graduated from Anaheim High School in Orange County CA. He received his medical education at UC Irvine College of Medicine where he finished at the top of his class earning the coveted AOA Medical Society honors. He completed his Orthopedic Surgery training LAC+USC Medical Center and then conpleted a Sports Medicine Fellowship where he focused on sports medicine, shoulder, knee, hip arthroscopy. He has published numerous book chapters on the topics of ACL injuries in soccer players, cartilage restoration, and athletic hip injuries. He is currently practicing Orthopedic Surgery in the City of Orange Orange County. He is a founding partner at Restore Orthopedics and Spine Center ( Dr. Mora’s practice focus is on sports related trauma, MMA injury treatment, arthroscopy of the shoulder, hip, knee and elbow, and partial and total knee replacement. He sees athletes of all levels including professional soccer and UFC/MMA patients. Dr. Mora’s family heritage is Peruvian. He speaks fluent Spanish.

For a consult, please call 714-332-5498

For more info become a Fan at Dr Mora’s Facebook page

Dr. Mora’s Twitter Link: 4000+ Followers

Restore Orthopedics and Spine Center

112o W. La Veta Ave, Third Floor

Orange, CA 92868

Office: (714) 332-5498