In research it has been determined that the size of the thigh in obese individuals is a major cause of their hip prosthesis is more prone to failure.
The study authors, from the University of Iowa in the United States, hip dislocations simulated as occurring in people and determined that greater thigh circumference creates instability in the hip in patients with morbid obesity (those with a BMI greater than 40).
The researchers propose that surgeons modify surgical procedures to minimize the chances of dislocation in obese patients and other designs to consider when selecting the hip prosthesis to be implanted in the patient.
Team of Jacob Elkins, of the University of Iowa in the United States, found that the thighs of patients with morbid obesity are so large that they are actually pushing each other out, and as a result end up forcing the prosthesis to step outside of his assemblage point.
It is known that there is a risk to 6.9 times greater dislocation in patients with morbid obesity compared to normal weight patients. But until now, the exact reasons for this were unclear.
Using a computer model created to better understand the forces at work on a hip prosthesis depending on the patient’s body, Elkins and colleagues analyzed the pelvis of six corpses and 146 healthy adults. They examined the effect of the pressure generated by the thrust of one thigh to the other about the hip prosthesis, thereby allowing for a wide range of movements ranging from sitting position to standing.
With the ability to simulate movements in human bodies of different sizes, the team was able to test different implants, reaching the above conclusion.