61 percent of U.S. adults are overweight or obese—and they present a growing problem in emergency departments across the country

Obesity—defined as a body mass index (BMI) greater than 30—is presenting problems for orthopaedic trauma surgeons across the country. Based on their size alone, obese patients require different treatment, whether in imaging the injury or positioning the patient on an operating room table, according to a series of papers presented during the Orthopaedic Trauma Association Specialty Day.

Stephen H. Sims, MD, moderator of the session, noted that obesity now rivals tobacco in terms of deaths, disability, and direct medical costs. More than 5 percent of total U.S. annual medical expenses are attributable to obesity; in 2003, the direct health costs of obesity were more than $75 billion.

According to a study presented earlier during the AAOS Annual Meeting, a 44-year-old woman with a BMI of 34 would have $11,000 more in hospital costs than if she had a BMI of 24. Among patients admitted for treatment following a frontal impact automobile crash, those with a BMI greater than 30 had a 39 percent re-admission rate.

Treating obese patients requires an unusual amount of effort, so much so that Dr. Sims urged the audience to submit claims for these patients with a modifier -22 and to document the difficulties in the operative note.

“I don’t get additional compensation 95 percent of the time,” he admitted, “but the increased work and risk certainly deserve documentation.”

Risks and complications
According to Madhav A. Karunaker, MD, one in five Americans is currently obese, and that figure is predicted to double by 2025. Obese patients have significantly greater mortality and longer average stays in hospital intensive care units. In addition, obesity has been linked to diabetes, hypertension, and coronary artery disease.

The short, thick necks and heavy chest walls of obese patients pose problems for airway control, making intubation and ventilation more difficult. The amount of fatty tissue makes it harder to identify normal landmarks, and the lower lung capacity of these patients affects considerations for anesthesia and increases the risk of pulmonary aspiration.

The patient’s weight can also cause pressure-related complications such as alopecia, compartment syndrome, nerve palsy, and permanent thoracic-level paraplegia unless special care is taken in positioning the patient on the operating table(s). Such patients also have generally higher surgical mortality and complications such as thromboembolic disease, infections, and increased blood loss. These difficulties are not limited to the obese adult; obese children have similar rates of failure, particularly for surgical treatment of fractures.

Radiology issues

“The basic problem in imaging is poor visualization due to the size of the patient,” noted Gerald J. Lang, MD. “The thick layer of adipose tissue blocks and scatters X-ray beams, resulting in a loss of crispness. Not only is the preoperative assessment more difficult, but the amount of tissue limits intraoperative visualization, making it more difficult to identify fracture lines, place implants, or assess fracture reduction.”

Although radiographs of joints distal to the elbow and knee are generally not problematic, Dr. Lang pointed out the difficulties in obtaining images of proximal portions of the extremities and the trunk. “Fine bony detail is often lost,” he said.

He suggested that preoperative radiographs of the trunk are best done with fixed (rather than portable) units and that the physician use grids placed over the film to increase contrast and filters to remove low-energy beams.

The patient’s size may also limit the effectiveness and use of computed tomography scans. Older machines have a gantry of 65 mm to 70 mm in diameter and table limits of less than 450 lb. A patient who exceeds these limits could damage the machine, making it unusable for all patients until it is repaired. Although manufacturers are now producing larger machines and stronger tables, not all hospitals may be able to afford the upgrades.

“The use of intraoperative fluoroscopy remains a great challenge,” said Dr. Lang. “In this situation, positioning is critical. The more you can compress the tissue, the better your image will be. You may need a team of people to move the tissue, and you may need to switch your fluoroscopy unit to a manual override to adjust the settings and obtain the best images.”

Femur fractures
In reviewing the options available to treat femur fractures in the obese patient, Clifford B. Jones, MD, focused on both retrograde and antegrade intramedullary nailing as well as external fixation. Although external fixation offers several advantages (percutaneous, no start site problems, easy insertion), the disadvantages (poor stability and high rates of pin tract infection, nonunion and malunion) do not make it a good choice for this patient population.

Rehabilitation is often difficult for obese patients, who frequently have a mismatch between their upper body strength and the total body weight. Usually, an “all or nothing” approach to weightbearing must be used; in the “nothing” approach, the patient is confined to a wheelchair. However, Dr. Jones noted that aquatic therapy is very helpful.

Soft-tissue techniques
The final presentation, by Michael D. Stover, MD, focused on soft-tissue techniques that can be used to address the increased risk of perioperative complications in obese patients. Careful preoperative planning, as well as careful tissue handling and draping, is required. The surgeon must be careful to remove all the dead tissue and to irrigate the wound thoroughly. Increasing oxygen and the dose and frequency of antibiotics may also be helpful in decreasing the risk of surgical site infection.

For more information on the challenges of treating obese patients, refer to Guss D, Bhattacharyya T: Perioperative Management of the Obese Orthopaedic Patient. J Am Acad Orthop Surg, 2007;14:425-432. Available at www.jaaos.org