Obesity and Knee Replacement: How it can Impact?

Please return when you have lost 20 Kg. This is a common recommendation made to obese patients when they are evaluated for a hip or knee replacement due to severe arthritis. In some cases, the recommendation is to lose even more weight – 30, 40 or even 50 kgs. This is often seen as an unattainable goal.

As anticipated, patients often express disappointment and discouragement in response to this information. It is understandable that many have already invested significant effort into weight loss with limited success. The pain associated with arthritis restricts their ability to exercise, which has contributed to their weight gain. Therefore, being advised to lose a substantial amount of weight before being eligible for joint surgery is perceived as an unreasonably challenging target.

What is knee replacement surgery?

Knee replacement surgery involves removing parts of the bones that make up the knee joint and replacing them with artificial implants. The main reason it is done is to relieve pain and stiffness in the knee caused by osteoarthritis. 

Most people who undergo this surgery have advanced knee arthritis, in which the knee cartilage is worn away and the surface of the knee becomes hollowed, eroded, and uneven. This is sometimes called "bone-on-bone" arthritis. The result is pain, stiffness, instability, and a change in body alignment.

The Connection Between Obesity and Knee Problems

The knees bear the brunt of body weight, absorbing pressure with every step. For individuals with obesity, a BMI of 40 or greater, the excessive weight increases the load on the knees, leading to faster wear and tear of the cartilage. This often results in conditions like osteoarthritis, a leading cause of knee replacement surgeries. Studies suggest that every additional pound of body weight adds about four pounds of pressure on the knee joints, exacerbating the damage over time.

Conversely, for every kilogram of weight lost, 3-4 kilograms of force is lifted from the knees. For instance, a 10-kilogram weight reduction can result in 30–40 kilograms of force being taken off the knee joints during walking. This reduction in force through the knee joints can lead to a reduction in pain and inflammation, allowing them to function more efficiently.

Why does obesity Rule Out Knee Replacement Surgery?

Although such recommendation by your doctor may come disappointing, the logical basis behind it is solid. It has long been recognized that individuals with a lot of excess weight are at an elevated risk of complications following this procedure and are less likely to experience the anticipated pain relief.



It is evident from several studies in the medical literature that there are higher rates of complications following hip or knee replacement surgery in patients with a high body mass index (BMI), with particularly elevated risks for those with a severe degree of obesity.

However, it is important to note that a significant number of these studies were conducted over a decade ago, and more recent studies are beginning to present a different picture. According to PubMed, a recent study presents a new perspective on the risks and benefits of joint replacement surgery for obese individuals, offering a positive outlook on an issue affecting a significant number of people.

How Obesity Affects Knee Replacement Surgery

Increased Surgical Risks

Obesity is associated with heightened risks during knee replacement surgery. These include:

• Anesthetic Complications: Obese patients may face difficulties with anesthesia administration due to altered airway anatomy and reduced respiratory reserve.
• Surgical Challenges: Excess soft tissue can make the surgical field less accessible, increasing the complexity and duration of the procedure.
• Infection Risk: Obesity is linked to a higher incidence of post-surgical infections, which can complicate recovery and, in severe cases, require revision surgery.

Impaired Recovery and Outcomes

Post-surgery recovery can also be more challenging for obese patients due to:

• Slower Rehabilitation: Excess weight may hinder physical therapy efforts, delaying recovery.
• Implant Longevity: Studies indicate that knee implants may wear out faster in obese patients due to the increased mechanical load.
• Reduced Mobility Gains: While many patients experience significant pain relief after surgery, mobility improvements may be less pronounced in individuals with obesity.

Obesity Should Not Contraindicate Knee Replacement

Although weight and high BMI have a negative impact on the longevity of primary total knee replacement surgery, a new study suggests that obese patients should not be excluded from the benefits of surgery. In fact, obese patients had an overall improvement equivalent to that of patients with a lower BMI.

According to PMC, obese patients undertaking total knee replacement are recommended to receive minimally invasive surgery (MIS) regardless of their BMI level. 

In general, patients are advised to lose as much weight as possible before surgery to reduce complications. However, some cases are referred for bariatric surgery if possible. 

Managing Obesity Before and After Knee Replacement

To optimize surgical outcomes and long-term joint health, managing obesity is crucial. Here are some steps patients can take:

Pre-Surgical Preparation

• Weight Loss Programs: Losing even a modest amount of weight before surgery can reduce surgical risks and improve recovery outcomes.
• Exercise and Physical Therapy: Strengthening the muscles around the knee can enhance stability and support during and after surgery.
• Nutritional Guidance: A diet rich in nutrients and low in processed foods can support weight loss and overall health.

Post-Surgical Strategies

• Commitment to Physical Therapy: A structured rehabilitation program is essential to regain strength and mobility.
• Lifestyle Changes: Maintaining a healthy weight through balanced nutrition and regular exercise can protect the new knee joint and prevent complications.
• Regular Follow-Ups: Monitoring progress with a healthcare provider ensures any issues are addressed promptly.

Conclusion 

Obesity has become a global health concern, with its prevalence steadily increasing over the years. Among its many adverse effects on health, obesity can significantly impact the joints, particularly the knees. 

Many patients with advanced, painful knee osteoarthritis are considered poor candidates for total knee replacement (TKR) surgery. At Turkey Luxury Clinics, we are proud to provide you with a multidisciplinary team of surgeons, physical therapists, and dieticians in order to achieve the best possible outcomes. Contact us now and our medical consultants will be ready to assist you with all your questions and concerns.