Sex After Hip and Knee Replacement

The short answer

Wait six weeks after a hip or knee replacement. After that, I place no restrictions on position.

That is the whole guidance, and it is the same for both joints. Most of what you will find searching this question is a diagram of forbidden positions that leaves people more anxious than when they started. The rest of this page explains why my answer is simpler than that.

Why six weeks

The reason is not that particular positions are dangerous. It is something more practical.

In the weeks after surgery the joint and the soft tissues around it are still healing, and they can be traumatized by an awkward movement or a sudden load. Sex is one of the few activities where you are genuinely not thinking about your body mechanics. You are focused on other things. You are not monitoring how far the hip is rotating or how much load is going through the knee — which is exactly the situation the early healing period does not tolerate well.

Six weeks puts you comfortably past that window. It is not a limitation based on positions; it is a limitation based on time.

About those position charts

You have probably seen them — illustrated guides showing which positions are considered safe after a hip replacement, usually broken down by whether the hip was done through an anterior or a posterior approach.

They exist for a real reason. They were built around dislocation risk, and dislocation risk is tightly linked to how the hip was approached during surgery. In a posterior approach, stabilizing tissue at the back of the hip is released to reach the joint, and until that heals the hip is more prone to dislocating in certain positions. Hence the diagrams, and hence the precaution lists those patients are sent home with.

Why my patients get fewer rules

This connects to something covered in more depth in what the 90-degree rule actually is.

The 90-degree rule — don't bend past 90 degrees, don't cross your legs, don't twist the leg inward — was developed for posterior hip replacement, for exactly the reason above. After a muscle-sparing direct anterior hip replacement, those stabilizing structures at the back of the hip stay intact. They are never released, so they never have to heal.

That is why I don't place routine hip precautions at all — and it is why the answer to this particular question is a date rather than a list.

Knees

The timeline is the same: six weeks, then no restrictions.

The reasoning differs slightly. A knee replacement doesn't carry the dislocation concern that drives the hip diagrams — the issue is simply that the joint, the incision and the surrounding soft tissue are still healing, and this is not an activity anyone is going to perform cautiously. The same principle applies: give it six weeks, then stop thinking about it.

Comfort tends to sort itself out over the same period. Knee replacements are often stiff and tender early on, and both improve considerably by the six-week mark — see the knee replacement recovery timeline for what else is happening around then.

Being honest about the number

I want to be straight about where six weeks comes from, because I would rather you understand the reasoning than treat it as a rule handed down from somewhere.

It is deliberately conservative. For most patients it is probably fine at four weeks, and I may well move the guidance there at some point. I use six because it is a safe cutoff from a clinical standpoint, and because the cost of waiting an extra couple of weeks is very low compared with the cost of injuring a joint that is still settling in.

If you are at five weeks and wondering whether the world ends at day 42 — no. It is a line drawn with a margin in it, not a cliff edge.

Just ask

This is one of the most common questions people have after a joint replacement, and one of the least often asked out loud. Patients go home and search for it instead, which is how they end up looking at a diagram of forbidden positions built for an operation they did not have.

It is a normal part of life and a normal part of recovery. Ask it at the end of a visit, or send it through the office if that is easier — but ask, rather than guessing.