Preparing for hip or knee replacement

If you are preparing for a hip or knee replacement, I want protein intake to be part of the plan. What you eat deserves attention alongside the exercises you do.

Start with the difficulties you have today and the time available before surgery. A useful plan should help you work on those difficulties while addressing any health issues that could affect the operation.

Start with what is difficult today

Tell your surgeon or physical therapist what has become difficult. Getting out of a low chair and walking through a grocery store place different demands on you. Those details help the team choose exercises with a purpose.

Ask what strength work, movement practice, and aerobic activity fit your current abilities. Resistance training means asking a muscle to work against a load, which could be your body weight, a band, or a weight. The appropriate starting point will differ for someone who already trains and someone who struggles to stand up.

Include joint mobility: how comfortably you can move, and where stiffness gets in the way. Ask your therapist how to adjust an exercise when it aggravates your symptoms, rather than guessing how much pain to push through. AAOS preparation guidance recommends discussing exercises with your doctor before surgery.

What can exercise before surgery actually do?

A structured program before an operation is often called prehabilitation, or prehab.

A 2023 systematic review of randomized trials found moderate-certainty evidence that prehab improved strength and function before knee replacement. For hip replacement, it supported improvements in strength and health-related quality of life before surgery. The review also found better function six weeks after knee replacement. That is a useful reason to work on strength while you wait.

The longer-term picture is less settled. A 2025 overview of reviews found benefits after hip and knee replacement, including strength and function, but the effects generally diminished over time and were concentrated in the first six months. The quality of the included evidence ranged from critically low to moderate.

Hip-specific research is growing. A 2026 review of 21 randomized trials found benefits from some exercise approaches while people waited for hip replacement. Confidence in most comparisons was low or very low. That review evaluated the period before surgery; it cannot tell us that those improvements will produce a faster recovery afterward.

Choose a program with a goal you can work toward now, such as improving strength or making daily activities easier. The research cannot promise the week you will be walking unaided after surgery.

Make a protein plan before surgery

Protein supplies amino acids your body uses to repair tissue and maintain muscle. Surgery increases the demand for protein for wound healing and immune function. That is why eating less simply because you are moving less can miss what your body needs during recovery. Perioperative nutrition guidance makes meeting protein needs a specific part of preparation and recovery.

About 1.6 grams of protein per kilogram of body weight per day is a practical target to discuss with your care team. The same guidance discusses a broader range of 1.2–2.0 g/kg/day for people under physiological stress, while acknowledging that the ideal surgical intake is not firmly established. Your target should account for your health, usual intake, and nutritional needs.

For an 80 kg person, about 176 pounds, 1.6 g/kg works out to 128 grams of protein over the whole day. That is the total from food and any supplements combined. It does not mean adding 128 grams of protein powder to your usual meals. A dietitian can help decide which body weight to use in the calculation and turn the target into portions you can manage.

Look at breakfast as well as dinner. Eggs, Greek yogurt, fish, poultry, tofu, beans, and lentils can all contribute. Plan protein-containing meals and snacks that you will be able to prepare or have help with after surgery. If poor appetite makes the target difficult, ask whether an oral nutrition drink would help. Enough food overall matters too.

What does the joint-replacement research show? A 2025 systematic review and meta-analysis found that protein or amino acid supplementation could reduce postoperative muscle loss, particularly in studies of essential amino acids. Effects on strength and function were mixed. The studies used different supplements and regimens; they do not establish that eating exactly 1.6 g/kg prevents infection or guarantees a faster recovery.

If you have kidney disease or have been prescribed a protein restriction, your target needs individual review. Bring that up before increasing your intake.

Address medical issues early

For people with diabetes, ask who will review blood sugar control and set an individual target before surgery. For people who smoke or use nicotine, ask for help reducing or stopping, including which cessation treatments fit the surgical team’s plan.

The 2023 ACR/AAHKS timing guideline conditionally recommends allowing time for improved blood sugar control in patients with diabetes and for nicotine reduction or cessation in patients with nicotine dependence. It does not identify one blood sugar target that fits everyone. These are conditional recommendations, so the decision needs to account for the person and the consequences of waiting.

Include GLP-1 medicines in the conversation

If you take a GLP-1 medicine, tell both your surgical team and the clinician who prescribes it. Include the dose, recent dose changes, and any nausea, vomiting, constipation, or trouble eating. If you are struggling to eat enough, ask for help with the nutrition plan too.

These medicines can slow stomach emptying, which matters for anesthesia planning. Multisociety guidance calls for an individualized decision involving the patient, procedural team, anesthesia team, and prescriber.

Ask for clear instructions about your medication and eating and drinking before surgery. Do not choose a stop date from a social media post or change the dose on your own.

Does getting stronger mean you should delay surgery?

The ACR/AAHKS guideline applies to people with moderate-to-severe symptomatic arthritis or advanced osteonecrosis who have tried nonsurgical treatment without enough benefit and have chosen joint replacement. For that group, it conditionally recommends proceeding without a delay solely to try more physical therapy or other joint treatments.

Using the time already available to prepare is different from requiring an extra course of exercise before someone can have an otherwise appropriate operation. Your surgeon can help decide whether a specific health issue justifies waiting.

Make the first days at home easier to manage

Arrange transport, help with meals and prescriptions, and a clear path through your home for the walking aid your team recommends. If reliable help is difficult to arrange, raise that before the surgery date. The home preparation guide walks through the practical details.

Bring an up-to-date medication and supplement list to your preoperative visit. Report a new illness or a skin problem near the planned operation, and follow your team’s preparation instructions.

A useful question to finish that visit is: “Given my health and how I move today, what are the two or three things you most want me to work on before surgery?”

Include your protein target in that discussion, so you leave with a plan you can use at home.