Healthy living enhances joint replacement outcomes

Patients who improve their lifestyle and maintain a positive mindset before undergoing total joint replacement (TJR) surgery are more likely to have better functional outcomes than those who do not, according to several studies presented at the recent American Academy of Orthopaedic Surgeons (AAOS) annual meeting held in San Diego. Researchers found that patients who smoke cigarettes, misuse alcohol, do not control their blood sugar levels, or have a poor attitude before undergoing total hip replacement (THR) or total knee replacement (TKR) surgery may double their chances of having postoperative complications. However, they noted that all of these risk factors are manageable by patients, making them excellent targets for prevention and intervention programs.

In a study of cigarette smoking, researchers examined whether current or previous tobacco use has an effect on postoperative recovery in veterans undergoing elective THR or TKR surgery. The odds of having site infections were 41% higher for current smokers than for those who had never smoked before, with significantly higher odds of pneumonia (53%), stroke (161%), and 1-year mortality (63%). For previous smokers, the odds were higher for stroke (114%), pneumonia (34%), urinary tract infection (26%), and pulmonary complications (30%). The researchers concluded that because the risk of complications is significant with smoking and even short-term cessation may provide protection, approaching surgical candidates for a preoperative smoking cessation program would be reasonable.

Researchers evaluated postsurgical complication rates among veterans who had undergone TJR surgery and had admitted consuming alcohol in the previous year in responses to the Alcohol Use Disorders Identification Test. Patients who reported the highest amount of alcohol consumption (at the level considered “alcohol misuse”) were most likely to experience complications-each additional point in the 12-point scale corresponded with a 29% increase in the expected number of complications-indicating the need for preoperative screenings and, possibly, interventions for alcohol misuse among joint replacement candidates.

In another study, researchers reported that patients with type 2 diabetes mellitus (DM) who had preoperative hypoglycemia and hyperglycemia fared worse after TJR surgery than those who were able to keep their blood sugar (HbA_1c) at normal levels. Surgeons conducted 121 consecutive primary TJRs on patients with type 2 DM and evaluated hypoglycemic, normal range, and hyperglycemic patient groups on the basis of their preoperative HbA_1c levels. The researchers found a significant trend toward worse scores on outcomes, complications, length of stay, and hospital costs in all categories among patients in the lowest and highest ranges and concluded that patients with DM who control their blood sugar before surgery inevitably will have better outcomes.

Patients’ mental approach before, during, and after surgery can help determine how well they tolerate the recovery process and their degree of functional improvement after surgery, according to a symposium presentation. Persons who recognize within themselves the ability to ensure that things will be all right consistently report less pain and disability for a given disease or impairment, it was noted. A team of researchers are studying the emotional aspects of musculoskeletal health in patients undergoing total knee arthroplasty through an NIH grant.

In one of several hip care studies reported at the meeting, researchers evaluated Medicare beneficiaries who had elective primary THR surgery for osteoarthritis (OA). The risk of needing revision was about 2% per year for the first 18 months postsurgery and then about 1% per year for the remainder of the 12-year follow-up. The risk was higher in men than in women and in patients aged 65 to 75 years than in patients older than 75 years. Patients operated on by surgeons who performed fewer than 6 THRs in the Medicare population each year were at higher risk for needing revision than those whose surgeons performed more than 12 hip replacements a year. These first national, population-based estimates of the rate of revision after THR surgery over 12 years confirm the risk associated with younger age, male sex, and low surgeon volume and underscore the need to choose an experienced surgeon who frequently performs THR surgery.

Because orthopedic surgeons often face the decision of whether to replace a THR in patients older than 80 years, another study compared patients older than 80 years with those younger than 80 years who had undergone revision surgery. Both age-groups indicated general improvements after surgery. Patients older than 80 years reported substantial clinical improvement and satisfaction; 84.2% in the older group reported no or only mild pain, compared with 79.8% in the younger group. However, more medical complications, dislocations, and postoperative fractures were seen in patients older than 80 years and mortality rates were higher. The researchers suggested that patients older than 80 years have revision surgery for pain relief and improved function, but with very good medical preparation before the procedure, and work with their primary care physician to obtain a comprehensive checkup.

The current generation of high-performance THRs offer improved functional capacity to active patients of all ages, according to a teaching seminar leader who presented at the meeting. The advantages-including durable implant fixation, improved biomechanics, larger-diameter bearings that provide greater stability, and lower wear–bearing surfaces for increased longevity-allow for earlier intervention in patients with hip arthritis.

Much of the research reported at the meeting focused on the knees. One study addressed questions about the decline in physical function over the long term in older patients who had undergone TKR surgery despite the absence of implant-related problems. Researchers examined 128 older patients who were living at the 20-year follow-up (average age, 82.3 years). Findings included the following: 95 patients could walk at least 5 blocks, nearly half of the patients reported unlimited walking, and only 3 patients were considered housebound. The investigators concluded that a remarkable functional capacity and activity level continues 20 years or more after TKR surgery and that their research refutes any perception that the importance of a well-functioning TKR diminishes over time because of an overall declining functional status.

In another study, replacing both knees in 1 surgery, or simultaneous TKR, was associated with significantly fewer prosthetic joint infections as well as other revision knee operations within 1 year after surgery, compared with TKRs performed in 2 separate procedures. However, simultaneous replacement was associated with a moderately higher risk of adverse cardiovascular outcomes within 30 days.

Several studies addressed the role that obesity plays in knee arthritis and a patient’s ability to recover from knee surgery. One study found that although weight loss via bariatric surgery may improve knee pain in obese patients who have knee OA, permanent damage to the knee resulting from being morbidly obese may occur.

Two other studies examined whether obesity contributes to greater complications after THR and TKR surgeries. In one, researchers found that the number of overall complications is significantly higher for “super-obese” patients than for those who are not obese. In the other, morbid obesity was found to contribute to a significantly higher incidence of complications, such as leg swelling, bacterial infections, and respiratory disorders. Another study found that isolated weight loss after bariatric surgery results in significant improvements in knee pain, stiffness, and function.

A research team found that TKR use doubled from 1997 to 2007, the proportion of procedures performed in younger age-groups tripled, and the proportion of obese persons undergoing TKR surgery increased by about 15%. Data suggested that expanded indications for TKR in younger patients (including sports-related injuries, obesity and, as a consequence of obesity, early onset of OA) may explain the dramatic increase in TKR rates in the United States.

For more information on these and other topics discussed at the AAOS annual meeting, visit the AAOS Web site at http://www.aaos.org. Or, contact the organization at AAOS Headquarters, 6300 North River Road, Rosemont, IL 60018-4262; telephone: (847) 823-7186; fax: (847) 823-8125.