Obesity, medically referred to as adiposity (overweight), is on the rise worldwide. In Germany, according to current studies, more than 25% of the population is obese. At the same time, the demand for endoprosthetics in hip and knee joints is increasing due to the aging society. However, joint replacement poses a particular challenge, especially in obese patients. The combination of adiposity and endoprosthetics is complex, as it affects both the risk of perioperative complications and long-term results.

This article highlights the risks, the optimal preparation of obese patients for joint replacement, and the importance of a healthy metabolism for the success of the operation.

Epidemiology: Obesity and joint replacement in numbers

• Increasing numbers: With the rising prevalence of obesity, the number of patients requiring joint replacement also increases. About 50% of arthroplasty patients have an elevated Body Mass Index (BMI) over 30 and are therefore overweight.
• Higher risk for osteoarthritis: Obesity (overweight, excessive weight) greatly increases the risk of osteoarthritis, especially in load‑bearing joints such as the hip and knee.

Why obese patients carry a higher risk in endoprosthetics

Increased risk of infection

Patients with obesity (adiposity, overweight) have a significantly higher risk for post-operative infections. Reasons for this include:

• Impaired wound healing: The reduced blood flow in fatty tissue delays healing.
• Higher skin surface load: The risk of skin lesions and infections in the surgical area increases.
• Elevated blood sugar level: Many obese patients suffer from diabetes or insulin-resistant metabolic condition, which further increases susceptibility to infection.

Technical challenges during surgery

• Reduced visibility: The thick soft-tissue layers make operative access and optimal placement of the endoprosthesis more difficult.
• Longer operation times: Studies show that surgeries in obese patients often take more time, which increases the risk for peri-operative complications.

Mechanical stress on the prosthesis

Obesity leads to excessive mechanical stress on the prosthesis, which:

• Loosening
• Early implant wear
• and an increased revision rate may result.

Preparing obese patients for joint replacement

Optimal preparation is crucial to minimize risks and maximize the chances of success of the operation.

1. Weight reduction before surgery

A significant weight loss before surgery can:

• Reducing the mechanical stress on the prosthesis,
• Reduce the risk of infection,
• Improve overall fitness and enable faster rehabilitation.

2. Benefits of weight loss

• Mechanical advantages: Reduced pressure on the joints also relieves the prosthesis.
• Improved wound healing: A lower BMI leads to better blood circulation and optimizes the body's healing capacity.
• Reduction of systemic inflammation: Weight loss can reduce inflammatory processes in the body, which could negatively affect the surgical outcome.

3. Preparation through physiotherapy

• Strengthening of the surrounding musculature
• Optimizing mobility before surgery

4. Metabolic Management

A recently published study shows that in obese patients in a catabolic metabolic state during surgery, the risk of complications also increases. This highlights the importance of a stable nutritional and metabolic status before the intervention. Consequently, it could also be disadvantageous to reduce weight too intensively before an endoprosthetic intervention.

Surgical peculiarities in obese patients

The implantation of a joint replacement in obesity (obesity, overweight) requires specialized surgical techniques to avoid complications.

Minimally invasive techniques

These can be beneficial in obese patients, as they facilitate a gentle approach and minimize the risk of wound infections.

Special implants

In overweight patients, particularly robust implants must be used, as well as ideal bearing pairs that withstand increased mechanical stress.

Aftercare and Rehabilitation

Individual rehabilitation plans

Obese patients require adapted plans that:

• Promoting gentle mobility,
• Address the stress on the new prosthesis,
• Support the gradual build-up of muscle structure.

Nutrition and Lifestyle

Sustainable weight reduction remains crucial even after surgery.

Future prospects in endoprosthetics for obesity (adiposity, overweight)

New technologies

• Robotics and navigation systems: Open up more precise implantation possibilities.

Conclusion

Joint replacement in obese patients undoubtedly carries specific risks, but can be successfully managed through comprehensive preparation, specialized surgical techniques, and sustainable aftercare. The benefits of weight loss before and after surgery are undeniable. However, a catabolic metabolic state around the time of surgery should be avoided. The combination of modern medicine and patient-centered care offers obese patients the opportunity to sustainably improve their quality of life.