Patient Factors in Outcomes

Why Body Weight Matters

Your weight affects the amount of force going through your hip and knee with every step. Extra weight can increase the load on a joint replacement and raise the risk of certain complications around the time of surgery — including wound healing problems, infection, and a more difficult early recovery.

This does not mean that every patient needs to reach an ideal BMI before surgery. In many cases that is neither realistic nor necessary. However, even a modest amount of weight loss before surgery can be helpful. Losing a few kilograms may reduce stress on your joints, improve your mobility, and make it easier to get moving in the early days after the operation.

If weight is a factor, the best approach is usually a realistic and steady one. This may include improving food choices, reducing processed snacks and sugary drinks, increasing protein intake, and adding low-impact exercise such as walking, cycling, or hydrotherapy where possible. The aim is not perfection — the aim is progress.

What You Eat Before and After Surgery

Nutrition is one of the most important and most overlooked parts of preparing for joint replacement surgery. Your body needs adequate protein, vitamins, minerals, and hydration to heal your wound, recover from the stress of surgery, and rebuild strength. If your nutrition is poor going in, recovery can be slower — wounds may take longer to heal, fatigue may be more pronounced, and muscle rebuilding harder.

Before surgery, focus on eating regular meals with good sources of protein — eggs, fish, chicken, yoghurt, legumes, or lean meat. A general target is 1.2–1.5 grams of protein per kilogram of body weight per day. Include vegetables and fruit each day, drink enough water, and limit excess alcohol. If you have known issues such as anaemia, low vitamin D, or difficulty eating well, address these early with your GP or a dietitian.

After surgery, nutritional demands are higher than normal. Your body requires additional protein and calories to repair tissue, regrow muscle, and support the immune response. Appetite may be reduced in the first days, but maintaining adequate nutrition — particularly protein — from the time you begin eating again is important. Staying well-hydrated also reduces the risk of blood clots and supports kidney function.

Building Fitness Before Surgery

The muscles around your hip and knee are critical to your recovery. They support your new joint, help you stand and walk, improve balance, and reduce the risk of falls. Patients who go into surgery stronger often find the first days and weeks of recovery easier than those who are very deconditioned.

Prehabilitation — a period of structured strengthening and conditioning before surgery — does not need to be extreme. Even a few weeks of focused work can improve your confidence and function. A programme may include strengthening the quadriceps, gluteal muscles, and core, as well as gentle stretching and balance work. If you use a walking stick or frame, practising with your aids before surgery can help them feel familiar afterwards.

Many patients worry that they cannot exercise because the joint is already painful. The goal is not to push through severe pain — it is to improve what you can safely improve. Even small gains in strength and conditioning before surgery can make a noticeable difference to your early recovery. A physiotherapist can guide you through a programme appropriate for your level of pain, stiffness, and fitness.

General Health and Mindset

When planning a hip or knee replacement, it is important to consider your general health as a whole. Age on its own is often less important than how well your medical conditions are controlled. Conditions such as diabetes, high blood pressure, heart disease, lung disease, and sleep apnoea can all affect surgical risk and recovery. The better these are managed before surgery, the safer the overall journey is likely to be.

Smoking is another important factor. It affects blood flow, wound healing, and lung function, and increases the risk of infection and other complications. If you smoke, reducing or stopping before surgery can make a real difference — ideally at least six weeks before the planned procedure. Support from your GP is very valuable here.

Your mental state can also shape the way you experience surgery and recovery. Patients who feel informed, prepared, and supported often cope better with the early discomfort and uncertainty that can come after a joint replacement. Anxiety often improves when patients understand what to expect. Reading the information provided, watching preoperative videos, asking questions in clinic, and discussing concerns openly can all help reduce fear of the unknown.

Expectations matter too. Joint replacement can be life-changing, but recovery takes time. The new joint needs to settle, the muscles need to strengthen, and confidence needs to build. Patients who understand that recovery is a process — not an overnight fix — often feel less frustrated and more in control. If you live with anxiety, depression, or other mental health challenges, it is helpful to discuss this before surgery so that extra support can be arranged where needed.

Getting Ready at Home

Practical preparation can make the whole experience much smoother. Before surgery, it is worth thinking ahead about what you will need in the first days and weeks after the operation. This may include clearing walkways at home, removing trip hazards such as loose rugs, setting up a comfortable chair with a sensible seat height, and organising support from family or friends for meals, shopping, transport, and general care.

It is also very helpful to understand what happens on the day of surgery and during your hospital stay. Knowing when to arrive, what to bring, what medications to stop beforehand, and what to expect after the operation can help you feel calmer and more prepared. Patients often say that once they know the plan, the whole process feels much less daunting.

In the early phase after surgery, the focus is on simple goals — getting in and out of bed safely, walking short distances, managing stairs if needed, and building confidence gradually. Pain relief and movement work together: the goal is to make you comfortable enough to mobilise, because early movement reduces complications and begins the process of recovery. Once home, recovery is not a race. Some days feel better than others. Steady overall progress is what matters most.

Common Patient Questions