What you can expect from knee and hip surgery (Harvard Healthbeat)

Your knees and hips are your largest joints. They support your body weight and work in close coordination so that you can run, squat to lift a child, or play hoops.

Over time, many of us experience knee or hip pain. Physical therapy, pain-relief medication, minor surgery, or some combination of these provides relief. But for some, knee and hip problems become so intractable that a knee or hip replacement becomes necessary.

Which is easier to perform, a hip or knee replacement?

An experienced surgeon could probably do a hip replacement blindfolded because you can feel everything. Components of the replacement are put right into the bones. But a knee replacement involves releasing ligaments, putting the components onto bone — and then getting things to balance out just right. Ligaments can be damaged or shortened by arthritis, so you really have to make sure the knee is stable. The joint must flex and rotate.

A hip replacement is a much less painful operation. People are on crutches for a while. Their hips feel normal. But it takes 6 to 12 months to recover from total knee surgery, and even then, the knee just doesn’t feel normal.

Why the difference?

The hip is really a much simpler joint. The knee has to balance off-center loads and move side to side. With a total knee replacement, you are removing a lot of tissue and bone. Post-operative pain is higher with knees because soft tissue affected by the surgery must stretch more than soft tissue around the hip.

So knee patients have to accept some limitations?

Running and jumping are out. The only time you might want to run is if a bus is going to hit you.

How about less drastic fixes for knees?

Not all doctors have much experience with Synvisc and the other viscosupplementation injections into the knee. They work reasonably well for some people, but you can’t expect good results if you have severe arthritis, with bone rubbing on bone.

Hip and knee replacement involve a lot of sawing and drilling.

They are real insults to the human body. You are working in a window where you don’t want to do too much, but you don’t want to do too little, either.

Does experience working with tools help doctors going into orthopedic surgery?

Maybe it does. In fact, men used to have a real advantage because they grew up using tools. But that’s not so true anymore. Women have started using tools more, and men are using them less, so it’s now pretty even.

What can people do to avoid knee or hip replacement? Stay active, keep your muscles strong, don’t get obese, have good genes.