52 Musculoskeletal Disorders FAMILY P RACTICE N EWS • July 1, 2005 Medicare Vertebroplasty Coverage: No Time Soon

An advisory panel listened to a day of mostly ally bed rest—is not without its risks. sign a 20% vertebral height restoration.” “During bed rest, virtually every organ Journal editors should require disclosure favorable testimony on vertebral augmentation. system is adversely affected,” said Dr. Mc- of anterior, middle, and posterior heights, Graw, who testified on behalf of the Soci- “as the vertebrae may fail in the middle BY JOYCE FRIEDEN augmentation patients showed a “statisti- ety of Interventional Radiology. “Bone den- portion, and yet there may be no change Associate Editor, Practice Trends cally significant improvement in bodily sity declines about 2% per week, and in anterior height,” said Dr. McKiernan. pain, mental health, physical function, so- muscle strength declines about 10%-15% “Without knowledge of all vertebral B ALTIMORE — Although some local cial function, and vitality,” compared with per week. Nearly half of normal strength heights, claims of vertebral height restora- carriers already cover vertebral augmen- the controls, said Dr. Lieberman, who is lost during the first 3-4 weeks of bed rest.” tion based [solely] on middle height may tation through vertebroplasty or kypho- serves as a consultant to several companies Other serious consequences of bed rest not be clinically relevant.” plasty, the Centers for Medicare and Med- that make surgical equipment for vertebral include pressure sores, deep vein throm- He also said that one recent article tout- icaid Services does not intend to consider augmentation. “Overall, these patients do bosis, and pulmonary emboli, he contin- ing the benefits of kyphoplasty cited two a national coverage policy for the proce- well with this intervention.” ued. “If we subject patients to 6 weeks of papers from his own research group. This dures, especially given the lack of solid Dr. Lieberman gave several reasons why bed rest, they’ve lost 12% of bone density citation was problematic because his data available, Stephen Phurrough, M.D., no randomized con- and half of their muscle group does not perform kyphoplasties, said at a meeting of the Medicare Cover- trolled trials had been The patients showed a strength, they have de- only vertebroplasties. In addition, the au- age Advisory Committee. done on the benefits of veloped a decubitus ul- thors used his group’s papers to make a “We have no open national coverage de- one procedure vs. the ‘statistically significant cer, and they have a point about vertebral compression frac- termination, and we have no plans to other. “I’ve been in- improvement in bodily 10% chance of a pul- tures less than 4 weeks old, “and our av- open a national coverage determination,” volved in five attempts. monary embolism. The erage fracture age is 4 months,” Dr. said Dr. Phurrough, who is head of To sum it up, it’s lack of pain, mental health, Society of Interven- McKiernan said. “The notion of less-than- Medicare’s coverage and analysis group. collaboration—we physical function, social tional Radiology be- 4-week-old fractures appears nowhere in The group does plan to “produce some have not been able to lieves that since verte- the text of either article.” type of guidance document that may dis- get various factions to function, and vitality.’ broplasty results in Panel members appeared to agree with till what we think about this particular field decide on how to do early mobilization, it is some of Dr. McKiernan’s points when it of spinal disease,” he said. That document the study or whether to participate,” he superior to conservative treatment.” came to voting on the questions put before will then be made available for comment. said. Fergus McKiernan, M.D., of the Center them. When asked to rate how well the Dr. Phurrough’s remarks came after a There are also study design and institu- for Bone Diseases at the Marshfield (Wisc.) evidence addresses vertebroplasty’s effec- day of mostly favorable testimony on ver- tional review board (IRB) issues. “One study Clinic, sounded a note of caution about the tiveness on a scale of 1-5—with 1 being tebral augmentation. “We are showing I was potentially involved in demanded a available data on vertebral augmentation. “poor” and 5 being “very well”—the pan- that these patients are better, and we’re sham procedure; my IRB would not let me First, he noted that one common el’s average vote was 2.0. When asked making a difference in their pain,” said do a sham procedure,” he said. Getting method of reporting vertebral height about mortality data, the panel was par- Isador H. Lieberman, M.D., a surgeon at funding for the study also is a problem. restoration following vertebral augmen- ticularly skeptical, giving it an average the Cleveland Clinic Foundation. But probably the most important prob- tation invariably favored smaller restora- score of 1.5. Results of a vote on the evi- Dr. Lieberman and colleagues performed lem is recruitment. “We’re dealing with an tions. For example, “if a 4-mm regression dence for kyphoplasty were similar. a prospective controlled trial on 329 verte- elderly population who don’t have time or of the superior endplate is followed by a “As patients expect this, a whole group bral augmentation patients, 70% of whom patience to come back for all these follow- 3-mm restoration, one could say this 3 of patients you wouldn’t think of doing had osteoporosis. Duration of symptoms ups or fill out all this paperwork,” Dr. mm constituted a 75% vertebral height this on will receive it,” said panel member prior to the procedure was 1 week to 5 Lieberman said. restoration,” he said. “Using this same Alexander Krist, M.D., a family physician years, mean follow-up was 55 weeks, and Kevin McGraw, M.D., a Columbus, method, if a 25-mm regression of the su- in Fairfax, Va. “There is [an unsystematic] the average hospital stay was 1.1 days. Ohio radiologist, testified that conserva- perior endplate is followed by a 5-mm el- process for figuring out who gets it and The researchers found that the vertebral tive treatment of vertebral factures—usu- evation, this reporting method would as- who doesn’t. That would be my fear.” ■ Surgeons Wax Skeptical on Mobile-Bearing Knee Implants

BY CHRISTINE KILGORE suring congruent contact between the femoral and tib- “Late dislocation occurs in this knee because of ad- Contributing Writer ial components. vanced wear,” said Dr. Hanssen, of the Mayo Clinic in These implants, said panelist Douglas A. Dennis, M.D., Rochester, Minn. WASHINGTON — Mobile-bearing knee implants are “allow increased conformity in both planes without dra- “One of the reasons to use the rotating-platform knee hyped in advertisements and demanded by patients, but matically increasing fixation stresses and the risk of com- has been to avoid osteolysis wear ...but osteolysis seems the jury is still out on whether the devices deliver what’s ponent loosening.” to be significantly higher [in patients with the mobile- promised. This, he said, reduces polyethylene wear—which bearing knee],” he said. During a panel discussion on “controversial issues and should be the focus of “any total knee design.” Polyeth- The rigid tibial trays that are required in the rotating hot topics” in primary total knee replacement at the an- ylene wear has been the major mode of total knee re- platform design also contribute to stress shielding of the nual meeting of the American Academy of Orthopaedic placement failure, said Dr. Dennis, of the Rocky Moun- proximal tibia, he said. Surgeons, several panelists objected to the idea that ro- tain Musculoskeletal Research Laboratory in Denver. “Why would you take a knee that [has only been stud- tating platform knee implants are superior in many ways “We have seen in our laboratory better kinematics in ied] in the elderly, has no better motion, no better patel- to fixed-bearing designs. gait with mobile bearings. They’re more tolerant of lo-femoral mechanics, has the unique complication of dis- “There’s certainly some skepticism here about whether condylar lift-off, which should reduce the potential for location and instability, and now appears to have some mobile-bearing designs are really more forgiving [of ro- polyethylene wear, and I think they’re more forgiving of wear and osteolysis problems and stress shielding prob- tational misalignment of the femoral and tibial compo- component rotational mal-alignment—the bearing has lems?” Dr. Hanssen asked. “My answer is no thanks.” nents] and whether there truly is less wear,” said William the potential to self-correct,” he said. Other panelists agreed. “The advertisements say [the J. Maloney, M.D., professor of orthopedic surgery at Stan- In a 10-year study of total knee replacements, Dr. Den- mobile-bearing knee] is the best thing, that it’s going to ford (Calif.) University, who moderated the discussion. nis and his colleagues found that mobile-bearing knees al- give us 20 years,” said Merrill A. Ritter, M.D., of the Cen- Rotating platform, or mobile-bearing, knee replace- low for a wider range of axial rotation without creating ter for Hip and Knee Surgery in Mooresville, Ind. “There ments are designed for potentially longer performance excessive polyethylene stresses. “A fairly large number [of [are] no data to support this, and there are too many with less wear to parts of the prosthesis. The devices have mobile-bearing knees] rotated greater than 20 degrees, things that do work.” been marketed and are recommended by some physicians, which is beyond the rotational boundaries of most fixed- Leo A. Whiteside, M.D., of the Missouri Bone and Joint particularly for younger, active, or overweight patients. bearing designs,” he said. Center in St. Louis, said that theoretically, the mobile- The mobile-bearing knees use three components—just Arlen D. Hanssen, M.D., argued that several studies bearing design should perform better. “What worries me like fixed-bearing replacements—but have a different have shown no difference in motion and no difference [are] the multiple reports of higher wear,” he said. bearing surface. The metallic femoral component and the in patello-femoral mechanics between fixed and mobile- Bearing surface is just one of several choices surgeons metallic tibial tray both move across a mobile polyethyl- bearing knees. Early dislocation and instability contin- make when performing total knee arthroplasty. The type ene insert. The insert creates a dual-surface articulation, ue to be a problem with the rotating-platform knee, and of fixation, the modularity of implants, and surgical tech- absorbing force across a greater contact surface and en- recently there have been reports of late dislocation. nique are also controversial, Dr. Maloney added. ■