Keeping you up to date on recent developments in orthopedics

Obesity a significant risk factor in complication rates following THA . . . Researchers from the Netherlands have found that obesity has a definite and significant impact upon the short- and long-term results of total hip arthroplasty. “The incidence of obesity is increasing, not only in the United States but also in Europe,“ Daniel Haverkamp, MD, PhD, said at the 12th EFORT Congress 2011. “Obesity is said to be a major risk factor for developing osteoarthritis, and if that is true we will see more obese in need of total hip arthroplasty (THA) in the coming years,“ So I think it is important to know whether there is a higher complication rate in the obese, and if the long-term outcome is worse.“ Haverkamp and his team performed an analysis of studies that compared hip arthroplasty results across different weight groups, with methodology being scored according to the Cochrane guidelines. The researchers extracted and pooled the data, using a weighted mean difference for continuous data analysis and a weighted odds ratio for analysis of dichotomous variables. “The results are really surprising,“ Haverkamp said. “Three times higher infection rate. Two times higher dislocation rate. Aseptic loosening — 1.8 times higher in the long-term.“ The team identified 15 studies from which they could extract data. In 10 studies covering 8,634 patients they found that obese patients experienced dislocation more frequently. In 6 studies covering 5,137 patients, aseptic loosening was more common in obese patients. Infection and venous thromboembolism were also more common in obese patients across 10 studies with 7,500 patients and 7 studies with 3,716 patients, respectively. Septic loosening and intraoperative fractures were found to be no different among obese patients, but Haverkamp noted this could possibly be attributed to low power.

Leg length may be affected by use of spinal anesthesia during THR . . . Use of spinal anesthesia during total hip replacement may impact leg length, according to researchers from Norway. Knut E.P. Hansen presented his team's study at the 12th EFORT Congress 2011 in Copenhagen. “We wanted to see if there was any correlation between type of anesthesia, leg length, total time spent in theater/recovery room, postoperative hospital stay, blood loss and operating time,“ he said. Hansen and colleagues performed a retrospective study of 170 patients who underwent primary total hip replacement (THR). The investigators excluded patients from the study who displayed abnormal anatomy or a had a body mass index of more than 46, as well as those who underwent simultaneous removal of internal fixation and those who had incomplete data. Leg length was measured by assessing the inter teardrop line and lesser trochanter on radiographs. Spinal anesthesia was used on 99 patients, Hansen reported, with 71 receiving total intravenous anesthesia (TIVA). The researchers did not notice any significant differences in average operating time, drop in hemoglobin to the first postoperative day, postoperative hospital stay or transfusion rate. However, they found a significant difference in the proportion of patients who displayed a leg length difference of more than 7 mm — 22% in the spinal anesthesia group and 6% in the TIVA group. They also noted average total time spent in the theater and recovery room was significantly higher in the spinal group than in the TIVA group. “Our studies seem to confirm earlier findings that the type of anesthesia can affect leg length in primary total hip replacement,“ Hansen concluded. “We speculate the spinal anesthesia has a more unpredictable effect on muscular tension, which could explain the leg length differences in the two groups.“

Minimally invasive surgery to treat scoliosis in teens now a 'feasible option' . . . A minimally invasive surgery to treat scoliosis in teenagers is now a “feasible option,“ says Vishal Sarwahi, MD, director of Spine Deformity Surgery at Montefiore Medical Center (Bronx, New York). “This new procedure to correct curvature of the spine involves three small incisions in the back, as opposed to standard open surgery, which requires a two-foot incision in the back,“ Sarwahi said. “While there are significant technical challenges in the new procedure, it has proved as effective as open surgery and involves less blood loss during surgery, shorter hospital stays, relatively less pain and pain medication and helps patients become mobile sooner.“ Sarwahi has performed seven of the procedures, and published the first professional journal article in the world on the topic in the August issue of Scoliosis. Until now, children with scoliosis, who are mostly girls, have been treated with traditional open surgery, in which a surgeon opens up a large section of the back, separates many back muscles and then places rods, screws and bone grafts along the spine to straighten the curvature. Sarwahi accomplishes all of this through three tiny incisions in the back. When curvature of the spine is severe, patients with scoliosis experience back pain and problems with heart and lung function. The best candidates for the new procedure are adolescents with a routine spinal curvature of 40-70 degrees, said Sarwahi, who followed the seven patients over two years. Minimally invasive surgery has been performed on adults with lumbar scoliosis in recent years, and the “next logical step is to apply minimally invasive surgical techniques to the treatment of adolescent scoliosis,“ Sarwahi said. The technical challenges Sarwahi and his team were able to overcome in the new procedure for children are significant. The spinal curvature in adolescent patients is more severe (50% to 100% greater than in adults; the number of vertebra requiring fusion is generally higher (from 7 to 13 vertebra); radiation exposure is greater due to multiple X-rays required to help place screws in each of the vertebrae; and the spine is twisted into three planes, which makes surgery more complex. The new technique takes longer than open surgery, Sarwahi noted, but he believes the time in the operating room will be reduced as the procedure is performed in greater numbers. In the study of seven patients, the surgeons limited the technique to curvature of the spine that was less than 70%. The technique provided “similar deformity correction as a standard open posterior spinal fusion,“ Sarwahi said.

Desert Regional unveils new joint and spine pavilion . . . The 18 private rooms at Desert Regional Medical Center's (Palm Springs, California) new Joint and Spine Pavilion are all equipped with Tempurpedic memory foam mattresses, the center notes. But the patients who come to the $7 million orthopedic facility aren't likely to spend too much time lolling around on them. The new unit, which will start accepting patients Sept. 7, is all about providing comprehensive care for patients who have had joint or spine surgery and getting them back on their feet as quickly as possible. In addition to the specially designed rooms, the facility also has a centrally located physical therapy room. “We get them up and around earlier, two to three hours“ after surgery, said Louis Stabile, MD, one of the hospital's orthopedic surgeons who will send patients to the pavilion. “I have patients who go home the next day. Most stay two days,“ Stabile said. The 9,448-square-foot facility is aimed squarely at aging baby boomers who have fueled a nationwide increase in joint replacements, said Douglas Roger, medical director of Desert Regional's joint program. The hospital already does about 2,000 joint and spine surgeries per year, about 1,200 requiring hospital stays, said Richard Ramhoff, director of marketing, but patients have been spread over different surgical wards, some of which were not close to the hospital's physical therapy room.

– Compiled by Holland Johnson, MDD