Why do people gain weight after hip replacement? (+3 facts)

In this article, we will discuss possible reasons for gaining weight after hip replacement surgery. We will also possible strategies to reduce weight after surgery.

Why do people gain weight after hip replacement?

Weight gain immediately after hip replacement surgery is mainly due to fluid accumulation in the body. Fluid accumulation can occur due to a medicine, swelling or an infection. During the recovery phase, the weight gain is temporary and will go away after the healing process.

During the hip replacement surgery, you will be given a lot of IV fluids, like normal saline, to maintain your blood pressure. You might get as much as three litres (around 10 pounds) of IV fluids. This causes fluid retention, oedema and weight gain.

However, prolonged healing time, stress eating, and physical inactivity might lead to a weight increase that would be difficult to shed off. That is why you should try to resume your normal healthy activities at the earliest to control your weight.

On the flip side, many researchers have reported weight loss in patients after hip replacement, especially in obese patients. Weight loss after hip replacement is also common in females. In most cases, no short-term weight change occurs (1).

How does weight increase after hip replacement?

After surgery, the patient may experience significant swelling, which is caused by both oedema and effusion. This is usually known as post-operative oedema and can occur locally or throughout the body. This can cause a slight increase in weight immediately after surgery but wears off after some time.

In some cases, the patient shows concern that the implant can cause weight gain after total hip replacement. To address such concerns, the weight of the implant was compared to the mass of bone and tissue removed post-surgery.

Based on the calculations, a surgeon who performed total hip replacement surgery on 339 patients, reported that the implant caused a net weight gain of 124.84 grams. This is equivalent to 0.275 pounds.

The authors concluded that such weight gain is negligible and other factors are more likely to cause weight gain as compared to the weight of an implant (2). 

What does research suggest?

In a cohort study, every patient (n=550) who underwent total hip arthroplasty reported weight gain after surgery. The patients had a 12% higher chance of significant post-surgical weight gain for every kilogram of pre-operative weight loss (3).

In another study, clinicians examined 3893 patients who underwent hip replacement surgery. After 2 years, 73% of the patients showed no changes in their body mass index (BMI). However, these inferences were made 2 years post-surgery and not immediately.

Irrespective of pre-surgical BMI or body weight, around 9-16% of the patients gained after following the hip replacement surgery. Also, elderly patients and females had less likelihood of gaining weight after the surgery (4).

In another postoperative clinical study, 50 patients (54% of the sample population) experienced weight gain after hip replacement surgery. Similarly, 41 patients (46% of the sample population) showed weight loss (5). 

In a comparative analysis, an average weight increase of 6.77 kilograms was noted in 75% of obese patients. On the other hand, 60% of patients in the non-obese group gained an average weight of 4.2 kilograms. However, 19% and 31% of the patients lost weight in the obese and non-obese groups, respectively (6).

Do physiological factors cause weight gain after hip replacement?

Physiological factors, age, physical activity, and obesity can have an impact on weight after hip replacement surgery. The factors include (7):

• Physical limitations: Immobility due to surgery, pain, and post-operative precaution limits the physical activity of the patient, leading to weight gain.
• Lack of exercise: Inadequate exercise and lack of physical activity may cause weight gain in patients with hip replacement.
• Age: In elderly patients, low-grade synthesis of adipokines, and inflammatory cytokines can lead to muscle atrophy.

These substances cause a gradual loss of muscle mass, which negatively affects the proportion of muscle mass to fat mass. Furthermore, fat penetrates already existing muscles and reduces the functional capacity of the muscular tissue. 

• Skeletal muscle quality: Due to bone loss and other physiological stress, the quality of the skeletal muscles decreases, which may cause weight gain.
• Perceived effort: Patients often feel they have to put extra effort into moving around or doing physical activities. 
• Walking aids: Patients on walking aids after hip replacement have 2-5-fold chances of gaining weight.
• Obesity: Even after receiving quality treatment and pain relief, obese patients may not enhance their involvement in physical activity.
• Underlying disease: Sometimes obese patients may have other disease conditions like diabetes, high blood pressure, and high cholesterol.

These factors can reduce the functional improvements as compared to non-obese patients.

Do psychological factors cause weight gain after hip replacement?

Psychological factors and overthinking can reduce the quality of life. Some of the psychological factors that can lead to weight gain post-surgery include:

• Pain: Instead of actual muscle pain, musculoskeletal pain may be the limiting factor for most patients. The pain limits their will to exercise to lose weight.
• Fear: Patients with hip replacement often fear tripping, falling, and exerting weight while walking. This reduces their mobility and will to exercise.
• Stress: Anxiety and stress can trigger hormonal imbalance, such as increasing the anti-duretic hormone (ADH). This can cause fluid retention and oedema.
• Stress eating: Patients tend to eat more due to stress. This can lead to weight gain.
• Steroids: Steroids are often given after surgery to reduce pain and oedema. These steroids can cause acid reflux and increased appetite.

How to reduce weight after hip replacement?

These tips can help reduce weight post-surgery:

• Daily Schedule: Making a schedule of eating and exercising can help in weight loss.
• Plan the meal: Planning and preparing a meal on time can reduce the chances of delay or eating from a restaurant.
• Avoid fast food: Avoid consuming fast food, fries and other oily stuff.
• Exercise: Doing exercise is the best method of shedding extra weight. Start with light exercise and then increase the intensity as needed.
• Add protein to diet: A high protein diet, such as chicken, or grilled meat, is essential for tissue repair and growth.
• Water: Drinking ample water speeds up the healing process. This will reduce carb hunger pangs.
• Avoid refined carbohydrates: Bread, pasta, and confectionary items contain refined carbohydrates that cause weight gain.

Post-surgery I felt quite bloated, constipated and thirsty for few days. This caused stress and I began to eat more than usual. I gained around 3 pounds in one month. However, I shedded these extra pounds by appointing a personal trainer and tried to control my diet by eating in portions.

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