Keeping you up to date on recent headlines in orthopedic healthcare:
New advances in replacing worn-out wrists .... Hip and knee replacements have changed the way many spend their golden years. New wrists may do the same. Now surgeons are successfully replacing joints that were at one time too complicated to remove. Some baby boomers are benefitting from a surgery that replaces the entire wrist. In the past, the best way to relieve pain was to fuse bones together – limiting mobility. Now orthopedic specialists replace the entire wrist – much more complicated than a hip or knee replacement. "There are eight bones in the wrist," said Randall Culp, MD, a hand and wrist specialist at the Philadelphia Hand Center at Methodist Hospital (Philadelphia). "If you add that to the two forearm bones, you're talking about 10 bones that need replacement." Surgeons make an incision in the back of the wrist. They implant metal parts to support the forearm and fingers, and a plastic spacer holds the joint together and allows movement. "We're also using what we call porous in-growth," Culp said. "We don't use bone cement anymore. This is all done through your own bone growing into the prosthesis." Doctors say the wrist prosthesis is a newer one so they are still studying how long it will last. They say most patients will do well for at least 10 years.
Lumbar matrix scan may revolutionize diagnosis and treatment of low back pain .... A new technology that may revolutionize the way low back pain is diagnosed and treated, while also significantly reducing healthcare costs, has been introduced by SpineMatrix (Akron, Ohio), a company that specializes in advanced spinal diagnostics. SpineMatrix's new, non-invasive Lumbar Matrix Scan uses high-speed computer processing of thousands of bioelectric signals to observe neuromuscular activity of the low back. The advanced diagnostic technology is designed to allow physicians to accurately identify the source of low back pain, which helps determine proper treatment and can result in significant savings for patients and the healthcare industry. Low back pain is the most common and costly disabling condition in the U.S., affecting nearly 31 million Americans. Current diagnostic methods used most frequently to detect lower back pain - such as X-rays, MRI and CT scans – take into account the anatomy of the back but not the physiology. These methods often fail to pinpoint the precise cause of pain for this reason. More than 85% of patients with low back pain are never given a specific diagnosis, leading to ineffective treatment and billions of dollars spent in unnecessary healthcare costs. The Lumbar Matrix Scan collects thousands of bioelectrical signals from the back and reconstructs them into easily interpreted images, which helps physicians to differentially diagnose lower back pain by identifying disc, facet and muscle pathology. The FDA-approved procedure monitors and displays the bioelectric signals produced by the paraspinal neuromuscular system using an array of 63 sensors that are placed on the back. The sensors are connected to a computer, which is calibrated to read the neuromuscular activity covered by the electrode grid. The image of the bioelectric signals produced by the low back muscles indicates the precise origin of low back pain. The procedure is fast, taking less than 15 minutes, and costs much less than an MRI, CT scan or invasive procedures. Factor in the savings on unnecessary treatments to relieve the pain, and the positive impact on healthcare costs significantly increases. In blinded clinical studies at the Cleveland Clinic, Texas Back Institute (Dallas) and Ohio State University College of Medicine (Columbus), the Lumbar Matrix Scan was shown to be a safe, non-invasive and effective diagnostic procedure.
Wear debris shown to be an effect, not cause of failure in ceramic-on-ceramic hips .... Wear debris and periprosthetic bone resorption appear to be effects rather than causes of failure in most ceramic-on-ceramic hip bearings, according to a research team from Italy. These results differ from those typically seen in revised metal-on-polyethylene bearings, in which foreign body cell reaction is the primary pathogenetic mechanism of failure, Nicola Baldini, MD, said in his presentation at the 10th EFORT Congress held in Vienna. The team from the Rizzoli Orthopaedic Institute (Bologna, Italy), analyzed clinical, radiographic, microbiological and laboratory data on 30 consecutive patients with failed alumina-on-alumina total hip arthroplasties (THAs) to see if foreign body reaction to wear debris played a role in periprosthetic bone resorption. As part of the examination, the researchers studied the retrieved implants and analyzed the histology of the periprosthetic tissues. Aside from 5 patients who required revision surgery due to late infection, all alumina-on-alumina cases failed due to secondary implant instability – including 19 cases involving screwed sockets – or to implant malpositioning (5 cases). One patient had a chronic dislocation. "In most cases, ceramic wear debris was absent or minimal, and it did not cause a tissue reaction," Baldini said. Although Baldini and his colleagues at Rizzoli have used ceramic-on-ceramic hips since the 1970s, "I think that the reliability of this solution is further supported by this study," he added. Baldini also said the failure rates between metal-on-polyethylene and ceramic-on-ceramic hips are comparable. Data collected in a prospective analysis from the regional registry at Rizzoli showed that the failure rate for ceramic-on-ceramic hip implants at 8 years is 1.9%, compared to 2.3% for metal-on-metal implants and 2.4% for metal-on-polyethylene.
Study finds fixed bearings showed slightly better ROM and Knee Society scores than mobile bearings.... Austrian investigators have found that a knee system which gives surgeons the option of a fixed- or mobile-bearing construct has good results at 8 years follow-up, with the knees with replaced patellas having better results than those without patellar replacement. For the assessment, Rainer Hochgatterer, MD, and Nikolaus Böhler, MD, prospectively studied 246 patients who received primary total knee replacement with the Innex Total Knee System made by Zimmer (Warsaw, Indiana) using either fixed- or mobile-bearing components. At a minimum eight-year follow-up, they found that the patients' mean range of motion (ROM) had improved from 105.54 to 110.05 and that the mean Knee Society Scores (KSS) had improved from 112.04 to 179.49. "In our implant and with our indications, the fixed bearings had a slightly better outcome regarding ROM and the KSS," Hochgatterer said. "There were no differences in the radiographic findings." Postoperative results in the total knee arthroplasty (TKA) with fixed or mobile bearings and patella replacement were superior compared to fixed or mobile bearings without patella replacement. Also, Hochgatterer said that the investigators were not expecting that finding. "The slightly better performance of fixed bearings in regards to the KSS really surprised us," he said. "We estimated both systems to perform equal in terms of general outcomes. The better performance of the fixed group regarding the ROM was also a surprise." The study results were presented at the 10th Congress of the European Federation of Associations of Orthopaedics and Trauma in Vienna.
— Compiled by Holland Johnson, MDD