Restricted Knee degree

[DEFENDER01]

I had a left knee replacement just over a year ago and got an infection.
They tried many ways of trying to get over the infection problem.
I ended up with having to have the knee replacement removed and a temporary spacer fitted so had no knee at all for 20 weeks

I have now had my knee replaced but the surgeon said I wouldn't get more than 90 degree bend at best I only have 70 degrees at the moment and am having physio.

As I like to go on a nice cycle ride and have 3 cycles one being a folding cycle to take on holidays.

My question is what modifications can be done to continue cycling.
Thanks in advance.

 

[byegad]

Shorter Cranks are possible. Remember that will effect saddle height, and gives a change in gearing, making climbing more difficult due to lack of leverage when you can no longer spin. All of that is possible to negate with lower gearing.

 

[Milkfloat]

I don't see why you would need any modification. If your saddle is correctly set then you won't need anywhere near 99 degrees.

 

[fossyant]

Give it a try, but you may have difficulty at the top of the stroke. That said, physio should help. Make sure your saddle isn't too low though.

 

[bobzmyunkle]

Someone I occasionally ride with uses something like this
https://www.sjscycles.co.uk/chainsets/left-fietsen-op-maat-rompedal-eccentric-pedal-device/

 

[mickle]

Different length cranks are for people with different length legs, what you need is one of the handful of 'swing' cranks or 'pendulum' cranks like the one posted by @bobzmyunkle

Pendulum cranks keep the pedal at the same distance from your saddle at the bottom of the stroke - but reduces the diameter of the circle that the rotation of the pedal describes, and so reduces the height of the pedal at the top of the arc.

They all have a range of adjustment so that you can slowly tweak it as your range of knee articulation improves.

There are some limitations regarding what cranks these will fit on. They must be straight, flat at the clamping area, not too tapered etc. Check with your supplier before splashing out.

Do not pay VAT on these. They qualify for zero rating as 'a product designed for the exclusive use of someone with a disability'.

 

[vickster]

I dealt with reduction in left knee flexion (mine ranges from about 95-110 Max but gets very painful at its limit with the physio pushing it) . My solution has been to ditch clipless and cycle on flat pedals on the arch.

Putting the saddle up isn’t an option as I need to be able to get my left foot down (knee won’t allow me to comfortably slide off saddle quickly) and I don’t don’t have full extension either (and an ankle injury on same side which has recently had surgery ).
Not ideal (not least I’ve needed to buy loads of new pedals) but it’s the only way I’ve been able to cycle for the last year or two. Upcoming surgery may help ROM but no guarantees.
My physio tells me 110 is needed for cycling (at least on ball of foot)

 

[Cycleops]

Electric bike or bolting a conversion on an existing one? The folder should be possible too.

 

[Sharky]

If you are going to try shorter cranks, explore Sinz Expert cranks. They are square taper/110 bcd and can be found for about £55 a pair.

I've been riding with 145 and 150mm cranks for a few years now. Did it to increase the hip angle as my stomach "muscles" were hitting my thighs. The shorter cranks and higher cadence with a lower gear leads to a much livelier riding style and deters you from grinding large gears.

Good luck

 

[Ming the Merciless]

When recovering from mountaineering accident I wasn’t allow to cycle till I could bend my knee to at least 95 degrees. I had a knee brace with a protractor thing for controlling maximum bend. I had to put saddle right at limit of extension and it was extremely hard pedalling. Fortunately my knee flexion returned to a full range of motion.

I think the pendulum thing sounds like what you’ll need.

 

[DEFENDER01]

Someone I occasionally ride with uses something like this
https://www.sjscycles.co.uk/chainsets/left-fietsen-op-maat-rompedal-eccentric-pedal-device/

Does this device mean you don't push down on the pedal at all.

 

[mickle]

Does this device mean you don't push down on the pedal at all.

Nope. It reduces the diameter of the circular path described by the pedal. The lowest point of the pedal remains the same height from the ground, so doesn't impact saddle height.

 

[mickle]

View: https://youtu.be/boS69sFvc3E

 

[Sharky]

See also
https://highpath.co.uk/

 

[DEFENDER01]

Nope. It reduces the diameter of the circular path described by the pedal. The lowest point of the pedal remains the same height from the ground, so doesn't impact saddle height.

Ohh ok I looked at the video and it looks like the device was just freewheeling which made it look like all the work was done with the other leg.
As all my cycles have different tappers would this fit all of them.