Exercise before a joint replacement helps a little, early, and mostly in getting moving again.

What the trials found

A 2017 systematic review and meta-analysis pooled 35 randomized trials with 2,956 patients having a hip or knee replacement ¹. After a pre-operative program, hip replacement patients had significantly less post-operative pain than controls, and both hip and knee patients had better post-operative function, with effect sizes the authors describe as small to moderate ¹. Knee replacement patients had significantly greater quadriceps strength; hamstring strength did not differ ¹. Hospital stays were shorter after both operations ¹.

A 2016 review took 22 trials with 1,492 patients and converted every pain and function result to a common 0-to-100 scale ². Prehabilitation reduced pain in the first four weeks after surgery by about 6 points on that scale, and the difference did not persist beyond four weeks ². Function at six to eight and twelve weeks improved by about 4 points ². The clearest gains were in the first days: patients climbed stairs about 1.4 days sooner, used the toilet unaided about 0.9 days sooner, and used a chair about 1.2 days sooner ². There was no difference in length of stay, quality of life or cost, and 18 of the 22 trials were at high risk of bias ².

How to read two reviews that disagree a little

Both reviews found the same direction: a small, early advantage. The 2017 review calls the improvements in function, strength and length of stay significant ¹. The 2016 review calls the same kind of gains too small and too short-lived to be clinically important, and points out that they did not touch the outcomes that matter most to health systems, such as length of stay, quality of life and cost ².

The difference is one of interpretation, and both are defensible. For a patient, the practical reading is this: a few weeks of exercise before surgery will not change what the joint is like a year later, but it may make the first week after surgery a little easier and get you up the stairs a day sooner. Both reviews note that the trials tested very different programs, so no one regimen has been shown to be the right one ¹².

What the patient guidance recommends doing anyway

The American Academy of Orthopaedic Surgeons advises asking your doctor about exercises you can do before surgery, for three reasons that do not depend on the trials: strengthening the upper body makes crutches or a walker easier to use afterward, isometric exercises help maintain the strength of the leg muscles, and learning the exercises that will be prescribed after surgery means being ready to do them when it counts ³. Its knee exercise guide describes those early post-operative exercises, quadriceps sets, straight-leg raises, ankle pumps and knee bends, and says they can begin in the recovery room ⁴.

The same guidance places exercise inside a broader list of ways to be in the best shape possible for surgery: cutting down or stopping smoking, eating well and addressing excess weight where the doctor recommends it, no alcohol for at least 48 hours before surgery, and telling the doctor about any other substances ³.

• Expect: a little less pain and better function in the first weeks, and stairs, chair and toilet a day or so sooner ¹².
• Do not expect: a different result at one year, a shorter stay in every study, or a change in cost or quality of life ².
• Do regardless: learn the post-operative exercises now, and build the upper-body strength the walker will ask for ³⁴.

Where it fits in preparation

Preparing for a joint replacement is more than exercise, and the parts that most often delay a surgery day are clearances, medication changes and testing rather than fitness. The TJV Readiness Score, described on our page about preparing for surgery, counts mobility and recovery support as one of eight equal parts, beside medical optimization, clearances, medications, testing, home support, expectations and education. Prehabilitation belongs in that one part; the other seven are what the surgical team will ask about first.

• Which exercises would you like me to do before surgery, and how often?
• Is there anything about my joint that makes a particular exercise unwise?
• Should I see a physical therapist before surgery, or is a home program enough?
• Which exercises will I be asked to do in the first days after surgery, so I can learn them now?

The trials here describe groups of patients on many different programs. Your surgeon and therapist decide what is safe and useful for your joint.