# Knee-Replacement Bicycle? **URL:** \ **Category:** Factual Questions\ **Created:** [June 6, 2013, 12:12am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252 "2013-06-06T00:12:02Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![bookaholic](https://avatars.discourse-cdn.com/v4/letter/b/dec6dc/32.png) [@bookaholic](https://boards.straightdope.com/u/bookaholic)\ **Post date:** [June 6, 2013, 12:12am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/1 "2013-06-06T00:12:02Z")
I had a total knee replacement done a few years ago. During my recovery I had a problem with the blood thinner I was prescribed and landed in the ICU for so long that my physical therapy was set back and I now can’t bend my leg more than about 90 degrees. Does anyone know if there is a, preferably stationary, bike that has a specially designed set of pedals that allows the circumference necessary to pedal it to be lowered in some way? I really miss my ‘Life Cycle’. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [June 6, 2013, 12:42am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/2 "2013-06-06T00:42:19Z")
You can get shorter cranks for a standard bike. I don’t know if it would make enough of a difference for you though. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [June 6, 2013, 12:44am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/3 "2013-06-06T00:44:39Z")
Just found this on YouTube. [![](https://img.youtube.com/vi/K5Q5ijmuoU4/hqdefault.jpg "Unicam Retroflex Cycle little or no knee bend. Daytona Beach Disabled Cycling") ](https://www.youtube.com/watch?v=K5Q5ijmuoU4) ---
**Author:** ![bookaholic](https://avatars.discourse-cdn.com/v4/letter/b/dec6dc/32.png) [@bookaholic](https://boards.straightdope.com/u/bookaholic)\ **Post date:** [June 6, 2013, 2:55am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/4 "2013-06-06T02:55:07Z")
Richard, that is exactly what I am looking for. I went to the site, and they DO have a stationary model. I just emailed them. Thanx ---
**Author:** ![Saintly\_Loser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saintly_loser/32/4045_2.png) [@Saintly\_Loser](https://boards.straightdope.com/u/Saintly_Loser)\ **Post date:** [June 6, 2013, 3:01am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/5 "2013-06-06T03:01:16Z")
I had a knee replacement too, quite a few years ago. I don’t have much more than 90 degrees of mobility in my knee. I’ve had good luck, though – riding a bike hasn’t been much of a problem for me. I was able to set up a bike so that I could pedal just fine. I suppose it makes a difference how tall (actually, how long of leg) you are in relation to crank length. I’m pretty tall, and I think that helps. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [June 6, 2013, 4:21am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/6 "2013-06-06T04:21:02Z")
I had a total knee13 months ago. Because I have a problem with pain meds I got off my therapy. My knee is still stiff. Anyone that has a total knee should get an exersize bike first. I am not understanding you would need a short crank. adjust the seat up away from the pedals then the knee does not have to bend as much. I used adjusting the seat down to increase the bending on my knee. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [June 6, 2013, 5:57am UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/7 "2013-06-06T05:57:19Z")
> [@Snnipe\_70E](#): > > I am not understanding you would need a short crank. adjust the seat up away from the pedals then the knee does not have to bend as much. I used adjusting the seat down to increase the bending on my knee. 90° is not enough knee bend for an average person on a properly set up bike, you need closer to 110°. Raising the seat is not a good option as a properly set up bike already has the set as high as it can go without causing problems. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [June 6, 2013, 2:38pm UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/8 "2013-06-06T14:38:28Z")
With the seat set where my leg is fully extended on the down stroke my knee bends close to 90 on the up stroke. My exersize bike is one of the recline styles. The style with the seat over the pedals the knee has to bend more. If I am riddding for my whole body health seat goes back and I use more resistance. When I am ridding for my knee seat comes forward and almost no resistance. In therapy they always started us on the bikes. At first it was just rocking the pedals back and forth as far as we could. Then turning the crank backwards. The first time anyone made it over the top it hurt. Then when I could pedal backwards without problems they had me go forwards. ---
**Author:** ![HotDogWater](https://avatars.discourse-cdn.com/v4/letter/h/35a633/32.png) [@HotDogWater](https://boards.straightdope.com/u/HotDogWater)\ **Post date:** [June 6, 2013, 2:53pm UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/9 "2013-06-06T14:53:25Z")
When I had my knee replaced I could not get past 90 during PT. So they brought me back in, knocked me out for 15seconds and touched my ankle to my ass. Twice. When I woke up I was past 90 for good! ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [June 6, 2013, 7:02pm UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/10 "2013-06-06T19:02:30Z")
> [@Snnipe\_70E](#): > > With the seat set where my leg is fully extended on the down stroke my knee bends close to 90 on the up stroke. My exersize bike is one of the recline styles. The style with the seat over the pedals the knee has to bend more. If I am riddding for my whole body health seat goes back and I use more resistance. When I am ridding for my knee seat comes forward and almost no resistance.. You shouldn’t have your leg fully extended, it should have about a 25° bend with the pedal fully down. This is both to maximize power output and reduce risk of knee injury from over extension. ---
**Author:** ![bookaholic](https://avatars.discourse-cdn.com/v4/letter/b/dec6dc/32.png) [@bookaholic](https://boards.straightdope.com/u/bookaholic)\ **Post date:** [June 8, 2013, 4:49pm UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/11 "2013-06-08T16:49:01Z")
I emailed back and forth with this guy who designs and manufactures a pedal adaptor. It looks like a good product, but it isn’t cheap. So I should be able to get it at some point. All I need now is a bike to go with it. I can pick one up at a yard sale somewhere. Raising the seat does not work. I am short and if I raise the seat, it is way uncomfy to pedal in that posture. Much better for the back as well to save up for this item. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 8, 2013, 10:18pm UTC](https://boards.straightdope.com/t/knee-replacement-bicycle/660252/12 "2013-06-08T22:18:35Z")
> [@Snnipe\_70E](#): > > I am not understanding you would need a short crank. adjust the seat up away from the pedals then the knee does not have to bend as much. I used adjusting the seat down to increase the bending on my knee. Shortening the crank would _further_ reduce the range of motion of your knee. I think a lot of people use cranks that are too long, or longer than necessary. I’m 5’9" with a 32" inseam and I find I’m most comfortable with 165mm cranks or even shorter, while most bikes sold in stores come with 170mm.