Written by Zita Sham, Fairuuz Saleh and Shiv Mohan Banka, Principal Physiotherapists at Phoenix Rehab.Clinically reviewed by Louise Yow, Principal Physiotherapist and Director, AHPC A1300363H.Last reviewed 28 September 2026.
A kneecap fracture is an extensor mechanism injury. That is the phrase worth knowing, because it explains why the rehabilitation is about getting the quadriceps to straighten the knee again rather than about the bone.
The bone heals. The quadriceps, which stopped being used the moment the knee was immobilized, is the part that has to be rebuilt, and it is the reason people are still limping and still avoiding stairs months later.
What the injury actually is
The kneecap sits inside the tendon that runs from your thigh muscle to your shin. When it breaks, the chain that straightens your knee is broken. If the pieces are still together and the chain still works, it is usually treated without surgery in a brace. If the pieces have separated, or you cannot straighten the knee against gravity, it is usually fixed with wires, screws or a plate.
The test that decides a lot of this is whether you can lift a straight leg off the bed. Your surgeon will have done it. It is worth knowing what the answer was.
Why the quadriceps is the whole story
Quadriceps strength falls fast when a knee stops extending under load, and the muscle that loses the most is the one that does the last few degrees of straightening. That is the part of the range that matters for walking normally and for controlling a step down, which is why going down stairs stays difficult long after going up has become easy.
A knee that cannot fully straighten under its own power also walks with a bent knee, which loads the front of the knee more, which hurts, which makes you use it less. The loop is the same one that shows up after every knee operation and the exit is always strength rather than rest.
Is this normal?
Expected in the first weeks and months: a knee that is swollen and warm, a thigh that is visibly thinner than the other one, stiffness that is worst first thing, aching after activity that settles by the next day, and being able to feel the metalwork under the skin. Kneecap hardware is close to the surface and often palpable, sometimes permanently.
Not expected: wound discharge, spreading redness or fever. Calf pain, swelling or tenderness, or breathlessness, which is a clot question needing same day medical review. A sudden inability to straighten the knee when you had been managing. And pain that is escalating rather than settling.
The four stages
- Stage 1, Calm and Protect. Brace and weight bearing exactly as your surgeon set them, swelling down, and quadriceps activation started immediately even without movement, because the muscle switches off within days.
- Stage 2, Move and Mobilize. Knee flexion recovered to the limits allowed, full passive extension achieved, and normal walking without aids. Criteria to move up are degrees of range and a symmetrical step, recorded.
- Stage 3, Rebuild and Strengthen. Quadriceps loaded properly and measured side to side. This is the long stage and the one that gets cut short.
- Stage 4, Return and Perform. Stairs down, squatting, kneeling if your surgeon permits it, and running or sport where that applies. Tested against the other leg.
Six months on and stairs are still the problem
Going down a step is a single leg eccentric quadriceps task, and it exposes a strength deficit that flat walking hides entirely. That is why people are discharged walking well and then discover what is missing at an MRT station.
Side to side quadriceps strength is a number. So is how far you can bend the knee and whether it fully straightens. If nobody has taken them, there is no basis for calling this a plateau. The Stalled Recovery Review is three appointments over three weeks with the same physiotherapist, $690 nett, no GST, and the first one is where those numbers get taken.
Every appointment is one to one with your physiotherapist for the full 45 minutes at $230 nett, no GST. See physiotherapy after surgery for the rest of the programs, and the Phoenix Recovery Protocol for how the stages work. Where your surgeon has given you a protocol, it takes precedence over anything here.
Logistics
When can I…
Your surgeon decides, based on healing and what your job demands. These are typical points, not permissions.
| Activity | Typical point | What has to be true first |
|---|---|---|
| Desk work | 1 to 2 weeks | You can get there safely on crutches and keep the leg up when it swells. |
| Driving | 6 to 9 weeks for the right knee, often earlier for the left in an automatic | Out of the brace, full control of the pedals and an emergency stop. Your surgeon agrees, and check your insurer. |
| Stairs, step over step | 8 to 12 weeks | Enough bend and enough quadriceps control to lower yourself slowly. |
| Standing work, lifting | 10 to 12 weeks or longer | Strength tested against the other leg. We can write to your employer about modified duties. |
| Running and sport | 4 to 6 months | Stage 4 criteria met and your surgeon’s clearance. |
| Kneeling | Varies | Often the last thing to become comfortable, particularly with wires in place. |
| Medical certificate | Your doctor issues it | Physiotherapists do not issue MCs. We can write a report on your functional limits for your doctor or employer. |
The program
What it costs and what is in it
Patella Fracture Recovery Program, Stages 1 to 4
Per 45-minute appointment, nett, no GST. The Patella Fracture Recovery Program is 12 appointments, $2,760 in all. You pay for each appointment as you attend it. If you need more, your physiotherapist shows you which stage criteria are still open, and each extra appointment is $230.
- An Assessment & Treatment first, at $230: which stage you are in, what is limiting you, and a written plan you walk out holding
- Swelling and scar management
- Bending progressed inside your surgeon’s limits, measured in degrees every visit
- Quadriceps strength measured against the other leg
- A home program, written down
- A one-page report to your surgeon at weeks 2, 6 and 12 if you were referred
- Your next stage review dated into the diary, with the same physiotherapist
Graduation, Not Discharge. The program ends when you meet the Stage 4 criteria for what you need to get back to.
Where are you with this right now?
1. It is settling on its own
Most knee pain that started with a specific moment settles over six to twelve weeks. Swelling that comes and goes with activity, and an ache after a long day, are usual in that window. If it is improving month on month and you can walk, take stairs and sleep, it is behaving normally. You do not need us for this, and we would rather say so.
2. It has stopped improving
You go down stairs one leg at a time. You have stopped squatting to pick things up. You test it before you trust it.
Pain settling is the first thing that happens, not the last. Quadriceps strength is the last thing to come back, and it does not come back on its own. That is the gap worth measuring, and it is not measured by how you feel on the day.
The Stalled Recovery Review is three appointments over three weeks with the same therapist, because what a joint does under load cannot be read in one visit. The first finds what is limiting it. The next two measure how it responds. $690, nett, no GST, which is three appointments at $230.
3. You have had surgery, or you have a date
Recovery after an operation has a shape, and knowing which stage you are in tells you whether you are on it. See the ACL Reconstruction Recovery Program, or knee physiotherapy if you are not sure which applies to you.
All of it runs on the same four stages. The Phoenix Recovery Protocol explains what each stage works on and what you have to meet to move up. No referral needed to start.
Next step
Find out which stage you are in
Pain is the first thing to leave. Movement and strength are the last things trained back, and most people stop before that part is done. One Assessment and Treatment is a single 45-minute appointment at $230, nett, no GST. Your therapist finds what is actually limiting you, treats it in the same appointment, and you leave with your current stage and a written plan.
Prefer to phone? Each of our five clinics has its own number on the clinics page. No referral needed to book.
Related reading
- physiotherapy after surgery
- knee physiotherapy
- Conquering the Climb: Understanding Knee Pain on Stairs
- Knee Pain Location Chart: Understanding Discomfort Sources
- Dealing with Knee Pain When Bending: A Comprehensive Guide
- The Phoenix Recovery Protocol, and the four stages
- All recovery programs, hand and physio
- Pelvic Fracture Physiotherapy
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