Hitting Zero vs Holding Zero: What Changes Your WalkTwo topics everyone talks about after knee replacement are extension and range of motion. Y'all often hear these questions:
“Did you get to 120 yet?”
“What’s your flexion?”
I do believe that they are both equally important. I don't think one overwrites the other. This blog is gonna focus on only extension.
Getting your leg completely straight. That's the goal.
With my first knee replacement, extension came back quickly. About three weeks in, I had it. By six weeks my range of motion was sitting at 120 and things felt balanced.
My second knee? That had a totally different personality.
I could hit zero occasionally at six weeks. But I was far from holding it. And that small gap, just a couple of degrees, started affecting everything.
My calf tightened.
My ankle felt off.
My hip, which had already been replaced, started grumbling.
I did have to change physical therapists around this time and when I went to the new physical therapist, that’s when it clicked.
When the knee isn’t fully straight during walking, our body compensates. It has to. Even missing two or three degrees shifts how your weight transfers through the leg. That changes mechanics up and down the chain.
This isn’t just about lying on a table and pushing your knee down. It’s about heel strike. It’s about quad activation. It’s about whether your brain trusts the joint yet.
Here’s something most people don’t realize (I know this because I was one of them).
Swelling can temporarily shut down our quad. Not because we’re not trying hard enough. But because our nervous system is protective. The joint is irritated, receptors send signals, and your brain says, “Let’s guard this.”
So, if extension feels heavy or stuck, it’s often not effort. It’s neurology and inflammation working together.
I also learned something the hard way.
I slept with my leg propped on a pillow most nights because I wanted comfort. Looking back, I really believe I reinforced a slight bend while I was trying to rest. Small habits matter.
And here’s the piece I think matters most, but you won’t see anyone talking about it….I never once doubted my extension would come back.
Not once.
We spiral when we think something is wrong. But extension can lag and still return beautifully. The body is recalibrating after trauma. It needs repetition, swelling control and a steady mindset.
If you’re sitting at 5 to 7 degrees right now, you’re not broken. You’re in process.
Inside the Knee Replacement Hub, I break down how I approached retraining extension functionally, what shifted things when I plateaued and how to know the difference between “hitting zero” and actually using it in real life.
Because straight on a table is one thing.
Straight under body weight is another.
And that’s where your walk truly changes.
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