Cement-Free Hip Replacement Has Good Long-Term Results

Twenty-year follow-up shows 96 percent of metal shells still going strong

18 may 2009-- Porous-coated acetabular metal shells inserted without the use of cement during total hip arthroplasty produce good long-term results, according to a study published in the May issue of the Journal of Bone & Joint Surgery.

Craig J. Della Valle, M.D., and colleagues at Rush University Medical Center in Chicago, conducted a follow-up of 114 (92 percent) out of 124 hips which had retained their original acetabular metal shell.

In all, there were five acetabular components which underwent revision for aseptic loosening or had radiographic evidence of loosening, and the modular acetabular liner on 14 hips with well-fixed acetabular shells had been changed due to excessive wear or as a function of treatment for osteolysis, the investigators found. A further eight hips had been recommended for liner changes, the researchers note.

"This cementless acetabular component provides durable fixation of the shell in primary total hip arthroplasty with survivorship of 99 percent at 10 years, 99 percent at 15 years, and 96 percent at 20 years postoperatively," the authors write. "No patient in this series who was older than 60 years at the time of the index arthroplasty has required a liner change (or had one recommended), and osteolysis as seen on plain radiographs has not been identified in any patient who was older than 65 years of age at the time of the index arthroplasty."

Financial disclosures were made in affiliation with Zimmer.

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Hip Replacement Leads to Improved Physical Functioning in Older Patients

By Todd Neale

DURHAM, N.C., 20 june 2008-- Osteoarthritic hips even in older Medicare patients are likely to respond to arthroplasty with invigorated physical functioning, researchers here found.
Medicare beneficiaries who underwent total-hip arthroplasty were about twice as likely to report improvement in mobility and in the ability to perform the activities of daily living (P<0.01 )
as those who didn't, Linda George, Ph.D., of Duke, and colleagues reported in the June issue of the Journal of the American Geriatrics Society.
Age did not have a significant effect on either of those measures, and in general, participants who did not receive a hip replacement worsened.
"We found that total-hip arthroplasty improves everyday life for patients and is as beneficial to people in their 80s or 90s as it is for someone in their 60s," Dr. George said.
"Physicians are less likely to present this option to the very old," Dr. George said, citing the long rehabilitation time, "but they should feel confident in recommending this procedure to those who are eligible for it."
In general, they said, those who did not receive a hip replacement worsened. Beneficiaries ages 85 and older (P<0.05) and Medicaid recipients (P=0.01) were significantly less likely to receive total hip arthroplasty.
Although the joint-specific benefits and safety of total-hip arthroplasty are well known, its effects on overall physical functioning have been less clear, the researchers said.
So they evaluated data from the Medicare Current Beneficiary Survey from 1992 through 2003 on patients who were diagnosed with osteoarthritis of the hip and who had received total hip arthroplasty (131) or no treatment (257).
All participants were interviewed at baseline and at least six months later. The average interval between interviews was about 13 months in the treatment group and about 15 months for the no-treatment group.
The researchers asked the participants to assess the level of difficulty in performing three items from the Nagi Disability Scale -- stooping or crouching, walking two to three blocks, and lifting objects weighing up to 10 pounds.
They also evaluated the level of difficulty the participants had in performing various instrumental activities of daily living -- light and heavy housework, meal preparation, and shopping -- and activities of daily living -- bathing, getting dressed, sitting, walking, and using the toilet.
Those who had no difficulty walking (P=0.01) or stooping (P=0.001) at baseline were more likely to be in the no-treatment group.
Those who had difficulty lifting, walking, dressing, or using the toilet at baseline were significantly more likely to receive a hip replacement (P<0.05 for all).
Compared with participants who did not receive treatment, those who did had significantly improved physical functioning according scores on the disability assessment and the activities of daily living evaluation.
Those who did not receive a hip replacement had worse physical functioning on follow-up compared with those who underwent the procedure, including statistically significant worsening in the ability to stoop, walk, or shop (P<0.05 for all).
In a logistic regression analysis, having a total hip replacement significantly predicted improvements on the Nagi measures of disability (OR 2.07, 95% CI 1.19 to 3.58) and in the ability to perform the activities of daily living (OR 1.90, 95% CI 1.11 to 3.24) (P<0.01 for both).
Participants who were diagnosed with osteoporosis were significantly less likely to show improvement in disability (OR 0.41, 95% CI 0.21 to 0.79) or instrumental activities of daily living (OR 0.55, 95% CI 0.35 to 0.84) (P<0.01).
Obese participants were less likely to have improved performance in activities of daily living (OR 0.42, 95% CI 0.22 to 0.82, P<0.01).
"These results suggest that effective treatment for osteoporosis and successful strategies for weight control can have positive effects for joint replacement as well as overall health," the researchers said.
The authors acknowledged that the study was limited by the self-reported data and small sample size. With a larger sample, they said, more of the coefficients may have reached statistical significance.
Also, they said, a longer interval between baseline and follow-up would allow for an assessment of the long-term effects of total hip arthroplasty.
The study was supported by a grant from the Institute for Health Technology Studies. The authors reported no conflicts of interest.
Primary source: Journal of the American Geriatrics SocietySource reference:George L, et al "The effects of total hip arthroplasty on physical functioning in the older population" J Am Geriar Soc 2008; 56: 1057-1062.

Gender Gap for Obesity and Osteoarthritis-Caused Hip Replacement

By Judith Groch
LUND, Sweden, 30 may 2008-- A high body mass index increases the risk of osteoarthritis-caused hip arthroplasty for men but not for women, according to a case-control study here.
However, both men and women who were overweight were likelier to need knee-replacement surgery, and the heavier they were, the greater the risk, Jonas Franklin, M.D., of Lund University and colleagues reported on line in the Annals of Rheumatic Diseases.
Studies have shown that a high BMI precedes knee osteoarthritis, but the relationship between high BMI and hip osteoarthritis has been less well defined, the researchers said.
The investigators compared 1,473 Icelandic men and women who'd had hip or knee replacement before the end of 2002 with 1,103 individuals who did not have joint replacement.
First-degree relatives of participating patients served as controls, while a randomly selected sample, representative of the Icelandic population, was used as a secondary control group.
Among the 1,473 patients, 872 were women, while among 1,103 controls, 599 were women, all born from 1910 through 1939. Participants had answered a questionnaire that included height and weight.
Adjusted for age, occupation, and presence of hand osteoarthritis, the odds ratio (OR) for having a total hip replacement was 1.1 (95% CI 0.9 to 1.5) for overweight men (BMI 25-30) and 70% greater for obese men (BMI>30), (OR 1.7 CI 1.0 to 2.9).
However, women who were overweight (BMI 25-30) or obese (BMI>30) were no more likely to need a new hip than normal-weight women. The OR for having a total hip was 1.0 (CI 0.8 to 1.3) for overweight women and 1.0 (CI 0.6 to 1.5) for obese women.
Being overweight or obese were factors in requiring knee arthroplasty for both men and women, the researchers reported.
Overweight men were 70% more likely to need total knee replacement (OR 1.7, CI 1.1 to 2.6), while the risk for obese men was more than five times higher (OR 5.3, CI 2.8 to 10.1).
Overweight women were 60% more likely to need knee replacement (OR 1.6, 95% CI 1.1 to 2.2), while obese women were four times more likely to need a new knee joint (OR 4.0, 95% CI 2.6 to 6.1).
For the knee, this study corroborates conclusions from earlier studies, the investigators said. For the hip, they added, some studies have claimed a positive relationship; others say not so. This study suggests that both may be right with a risk for men but not for women.
There may be anatomical, mechanical, and biochemical reasons for the different effects of high BMI on hip and knee osteoarthritis, the investigators said.
For example, it has been proposed that the gender differences for the effect of weight on the knee are caused by a difference in anatomical structure. Joint alignment and BMI may interact as risk factors for the knee, whereas such interactions may not be present for the hip joint.
Study limitations included voluntary participation so that non-participants may have differed from the study group. Because high BMI correlates with higher mortality, the results may have been influenced toward the null. However, this was not so in women's hip osteoarthritis where BMI was similar to that of the controls.
In addition, height and weight were self-estimated and many high-risk obese patients may never have been offered joint replacement.
Although the BMI of the controls was more like that of the cases than would be expected, such a bias would have a similar effect on men and women, which does not explain the weaker association for women and hip replacement, the researchers said. The fact that primary controls were relatives of the patients and secondary controls were from the general population probably contributed to the correlation of BMI among patients and controls.
This study supports a positive association between high BMI and total knee replacement in both sexes, but the association for hip replacement and BMI seems to be weaker, and possibly negligible for women, the investigators concluded.
No competing interests were reported. This study was supported by the Scientific Foundation of Akureyri Central Hospital, The Swedish Research Council (medicine), Lund Medical Faculty and University Hospital, the King Gustaf V 80-year Fund, The Swedish Rheumatism Association, and the Kock Foundations.
Primary source: Annals of Rheumatic DiseasesSource reference:Franklin J, et al "Sex differences in the association between body mass index and total hip or knee joint replacement resulting from osteoarthritis" Ann Rheum Dis 2008; DOI: 10.1136/ard.2007.086868.

Obese Patients at Greater Infection Risk After Hip Replacement


FRIDAY, 24 may 2008 -- Obese patients are at increased risk for infection and dislocation following revision (second) hip replacement surgery, according to a study by researchers at Geneva University Hospitals in Switzerland.
They evaluated the impact of obesity on the incidence of serious complications after revision total hip arthroplasty (THA) in 114 women and 90 men, mean age 71.6, over a period of up to five years. The researchers also evaluated whether functional improvement, pain and satisfaction differed between obese patients and healthy-weight patients.
The findings revealed a strong correlation between obesity and high rates of adverse events, as well as lower functional gains and more persistent pain, following revision THA.
Overall, 20 complications occurred in 17 (33 percent) of the 52 obese patients, compared with 18 complications in 13 (9 percent) of the 152 non-obese patients. Obese patients (body-mass index of 30 or more) had four times more surgical site infections and 3.5 times more dislocations than non-obese patients.
The risk of one or more adverse events increased with rising BMI. Patients with a BMI of between 30 and 34.9 were 4.5 times more likely than normal weight patients to suffer problems, while those with a BMI of 35 or more were 10.5 times more likely to experience complications.
After five years, obese patients had moderately lower functional improvements and higher levels of routine hip pain.
The study was published in the May issue of Arthritis Care & Research.
"Surgeons, patients and referring physicians should be aware of an increased risk in this [obese] patient group," lead author Dr. Anne Lubbeke said in a prepared statement. "Further studies are necessary to evaluate whether changes in medical preparation, surgical technique, and implant choice can help reduce the adverse event rate in obese patients undergoing revision THA."

Long-term improvement seen with hip replacement

Total hip arthroplasty (THA), or hip replacement, is an effective treatment for osteoarthritis (OA), but most studies have only followed patients for up to one year. A new study published in the December issue of Arthritis Care & Research (http://www.interscience.wiley.com/journal/arthritiscare) examined patients after an average of eight years following hip replacement and found a long-term positive impact on their physical functioning.
Led by Professor Cyrus Cooper and Ms. Janet Cushnaghan of the University of Southampton in Southampton, UK, the study included 282 patients from two English health districts who had OA and were placed on the waiting list for a hip replacement between 1993 and 1995. It also included 295 matched controls from the general population. At the start of the study patients were interviewed about hip injury, pain, physical function, vitality and mental health. In addition, their BMI was calculated, their hands were examined for Heberden’s nodes, an indication of OA, and their hip X-rays were evaluated for severity of OA. Between 2001 and 2004, they completed a self-administered questionnaire asking if and when they had undergone hip replacement, as well as questions about their physical function, vitality and mental health. Follow-up of the patients took place an average of eight years following hip replacement.
The results showed that patients who were waiting for a hip replacement had markedly worse physical functioning than the controls but only small differences in vitality and mental health at the start of the study. By the time of the follow-up, the physical functioning of the OA patients had improved (while that of the controls had deteriorated) but their vitality had deteriorated. In addition, better physical functioning at the start of the study was associated with a greater decline at follow-up, but higher BMI seemed to have no impact. Those with more severe OA according to their X-rays showed the most improvement in physical functioning.
“Our findings are consistent with a sustained beneficial impact on physical functioning following THA for OA, but we found no evidence for parallel improvement in vitality or mental health,” Professor Cooper stated. The researchers noted that the study is limited because it was an observational investigation as opposed to a randomized controlled trial and information about the patients’ disease and surgical procedures was limited. But this weakness was offset by the fact that the study had a long follow-up interval and a relatively large number of patients and controls. “Even when allowance is made for possible confounding effects, the long-term improvement in the physical functioning of the cases is striking when set against the decline that occurred in controls,” the authors note, suggesting that the benefits of hip replacement are substantial and long-lasting.
Although some previous studies have suggested that hip replacement benefits mental health as well, the current study did not find this to be the case, possibly because the mental health status of the patients at the beginning of the study was no different from the control group, even though they had greater physical limitations. Regarding the finding that BMI did not affect long-term physical functioning, the authors suggest that surgeons are perhaps careful in selecting obese patients for this procedure, but in any case a BMI in the range of up to 30 should not be a deterrent to hip replacement as long as the patient is healthy enough to undergo surgery.
The authors conclude that the study adds to the accumulating evidence of the long-term benefits of hip replacement, especially in patients with more severe changes seen on X-rays, and that perhaps these patients should be given higher priority for the procedure.