If someone needs total knee or total hip replacement surgery and their weight is significantly higher than it should be, a doctor may advise them to lose weight before undergoing the procedure. It is important to be in the best health possible before your surgery. Even though you may feel fit and healthy at your current weight, studies show that a patient with a BMI greater than 40 is more likely to experience serious complications both during and after surgery than a patient of normal weight. Losing weight helps to ensure the post-surgical recovery process goes smoothly.
A study published in the Journal of Bone and Joint Surgery looked at 203 people undergoing knee replacement who had a BMI of 40 or more. Within the study group, 29 people (14%) lost 20 pounds or more before surgery. Researchers compared these people to people who lost 5 to 10 pounds or did not lose weight at all. What is notable about this study is that the patients who lost weight were still considered morbidly obese. People did not have to reach what might be considered a “healthy” weight to reap benefits.
The researchers found that people who were morbidly obese and lost at least 20 pounds were more likely to have shorter hospital stays and be discharged to their homes, rather than to rehabilitation facilities. These patients also experienced fewer complications. When it comes to losing weight prior to knee replacement surgery, people don’t have to strive for perfection. Smaller goals may be less intimidating, more achievable, and still have benefits.
Patients with obesity are more likely to have certain diseases and health conditions that increase the risks of surgery. These include cardiovascular disease, high blood pressure, type 2 diabetes, obstructive sleep apnea, and metabolic syndrome, a group of health conditions that increase your risk for developing cardiovascular disease. If a patient has one of these conditions, their doctor will work with them to ensure that it is managed and under control before undergoing a joint replacement procedure.
Patients with diabetes need to ensure strict glucose control in the weeks leading up to and immediately after surgery. Numerous studies show a significant correlation with wound healing and infection following joint replacement surgery in patients with poorly controlled blood glucose. Most providers will not perform joint replacement in a patient with a hemoglobin A1c of greater than 7%. Poor glucose control is typically resolved with dietary changes as well as careful monitoring but may require some medication changes.
Furthermore, obesity can lead to complications post surgery. It is more difficult to administer anesthesia to a patient with obesity. Complications may be due to the patient’s body shape and anatomy or to health conditions that can affect breathing. Challenges for the anesthesiologist include locating veins to administer general anesthesia and necessary medications and ensuring that oxygen and airflow are sufficient. It is also more difficult to properly position the needle when delivering spinal and epidural nerve blocks and other types of regional anesthesia. Obesity can also result in longer operative times. Compared with a patient of normal weight, a patient with obesity is more likely to experience more complications after surgery such as infection, poor wound healing, difficulty breathing, blood clots, and pulmonary embolism (a blood clot in the lungs).
A patient may also experience more implant and prosthesis complications after surgery including component loosening and failure as well as dislocation. In some cases, a second “revision” surgery may be necessary to remove failed implants and replace them with new ones.
The key to losing weight is a decision to perform a lifestyle change, encouraging daily physical activity and limiting poor diet and health choices. In general, a person should try to make lifestyle changes such as reduction of fat and calorie intake by making healthy food choices and trying to eat meals that are full of fruits, vegetables, whole grains, lean meats, and low-fat dairy. Drink plenty of water and avoid sugary drinks that are high in calories.The other crucial factor is to get as much physical activity and exercise as possible. Having constant hip or knee pain may result in a person not being as active as they were before. Low-impact activities such as swimming, biking, or using an elliptical machine will put less strain on the joints than strenuous exercise and will still be effective in helping with weight loss.
It is recommended to rather choose to adopt a healthier lifestyle before surgery as research has shown that most patients maintain their BMI post surgery rather than adopting radical lifestyle changes at that junction. A patient can work in conjunction with their doctor to find healthy lifestyle changes that fit their habits and lifestyle.
- Weight Loss and Joint Replacement Surgery
- Keeney BJ, Austin DC, Jevsevar DS. Preoperative Weight Loss for Morbidly Obese Patients Undergoing Total Knee Arthroplasty. The Journal of Bone and Joint Surgery. 2019 Aug 21; 101 (16): 1440. DOI 10.2106/JBJS.18.01136
Dr. Matthew Russo
Dr. Russo is a third-generation orthopedic surgeon in Scottsdale, AZ specializing in total hip and knee replacement surgery. He feels very grateful to have the opportunity to serve the Phoenix community as an orthopedic surgeon, just as his father and grandfather have done, for over 30 years.