Total knee replacement is one of the most successful surgeries in modern medicine. The catch is that the result depends almost entirely on what happens in the three months after, not on the surgery itself. If you do the work, you walk pain-free for the next twenty years. If you don't, you live with a stiff knee that never quite worked.
What the surgery actually involves
The worn cartilage and bone at the end of your femur and the top of your tibia get cut away and replaced with a metal cap on each side. A plastic spacer sits between them. The kneecap is often resurfaced too. The result is a brand new joint surface where bone used to grind on bone.
Most patients are 60 or older. Most have been living with osteoarthritis for years before deciding to do it. The surgery hurts. The first two weeks are the worst pain most patients have ever experienced. By week six it's tolerable. By month three most people are back to walking the dog and doing the shopping.
The single most important number: range of motion
By six weeks after surgery your knee needs to bend to at least 90 degrees and straighten fully. If it doesn't, the scar tissue starts to set and getting that range back becomes much harder. We've seen patients lose 30 degrees of knee bend because they were too sore in week three to do the boring range of motion work.
The goal at twelve weeks is 120 degrees of flexion. That's the angle you need to get out of a low chair, get in and out of a car comfortably, and walk up stairs without compensating.
What the timeline looks like
- Day 0 to 7: In hospital. Standing, walking with a frame, ankle pumps, quad sets, knee bend exercises. Pain is high. Take the medication.
- Week 1 to 3: Home with a frame or crutches. Daily range of motion. Walking little and often. Ice and elevation after every session.
- Week 3 to 6: Transitioning off the frame to a single crutch or stick. Stationary bike if the knee bend allows it. Walking distance increasing. Target 90 degrees by week six.
- Week 6 to 12: Walking without aids. Light strengthening. Step-ups, sit-to-stands, leg press. Target 120 degrees by week twelve.
- Month 3 to 6: Strength is the focus. Quads, glutes, calves. The knee feels good but the muscles around it have atrophied. Rebuild them or live with the limp.
- Month 6 to 12: Return to recreation. Bushwalking, golf, swimming, doubles tennis. Heavy impact and contact sport are not recommended, the implant won't last as long.
The pain is real, and it's normal
Patients are often shocked by how painful weeks one to three are. This is the most common reason people fall behind in their rehab. The pain is normal. It comes from the bone surfaces healing, the swelling stretching the soft tissues, and the joint capsule being cut and stitched.
Take the pain medication as prescribed. Do the exercises within the pain you can tolerate. Ice for 15 minutes after every session. The pain follows a predictable curve, by week four it drops noticeably, by week eight most patients are off all pain medication.
The first six weeks decide your range of motion. The next three months decide your strength. Most patients focus on the first six weeks and forget about months three to six, which is exactly when the gains compound.
Common mistakes
Three patterns we see at the Liverpool clinic. First, stopping too early. The knee feels okay at week ten so people stop coming. That's the moment to push strength training, not back off. Second, walking heel-strike-only out of fear. The knee needs to bend through gait. Walking like a robot creates compensations elsewhere. Third, comparing yourself to other people's recovery. Genetics, age, body weight, pre-surgery strength all matter. Your timeline is your timeline.
How we structure TKR rehab
We typically see total knee replacement patients twice a week for the first six weeks, then weekly through month three, then every two to three weeks through month six. HICAPS for private health, Medicare EPC available if you have a GP care plan. Book a 60-minute initial within the first two weeks of surgery if you can. The earlier the rehab structure is in place, the better the long-term outcome.