Medical Studies

Pseudotumours Risk For Hip Resurfacing Highlights Need For Regular Clinical Follow-up For New Devices

Link  http://www.medicalnewstoday.com/articles/114601.php

July 11, 2008

As the incidence of metal-on-metal hip resurfacing has increased in recent years, especially in younger patients, research published in the Journal of Bone and Joint Surgery - British Volume (JBJS-Br) discusses occurrences of "pseudotumours" as a result.

The researchers estimate that approximately 1% of patients who have metal-on-metal hip resurfacings develop pseudotumours within five years of treatment. A pseudotumour is 'a soft-tissue mass associated with the implant…neither malignant nor infective in nature', but that causes pain and discomfort to the patient.

Most worryingly for patients and doctors is that the causes of the tumours are unknown. The research discusses possible causes including 'toxic reaction to an excess of particulate metal wear debris.' The article stresses the need for further research to be done into the incidence of pseudotumours in patients who have had this treatment.

The paper concludes that the incidence of pseudotumours must be related to metal-on-metal hip resurfacing highlighting 'the need for regular clinical follow-up for new devices'. Such follow-up would follow NICE recommendations, but the current NHS climate makes this difficult, if not impossible, to achieve.

Read the research abstract

Notes

- The Journal of Bone and Joint Surgery - British Volume is a world leading orthopaedics journal with an Impact Factor of 1.868

- JBJS-Br publishes twelve issues a year of high-quality, peer-reviewed research, overseen by an international editorial board led by Editor James Scott

- The Journal was first published in 1948 by The British Editorial Society of Bone and Joint Surgery, a registered charity (No. 209299), with the object of the advancement and improvement of education in orthopaedic surgery and allied branches of surgery and the diffusion of knowledge of new and improved methods of teaching and practicing orthopaedic surgery in all its branches

- You can find out more about the Journal at http://www.jbjs.org.uk

Journal of Bone and Joint Surgery, British Volume

Link  http://www.medicalnewstoday.com/articles/114601.php

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11, 2008

As the incidence of metal-on-metal hip resurfacing has increased in recent years, especially in younger patients, research published in the Journal of Bone and Joint Surgery - British Volume (JBJS-Br) discusses occurrences of "pseudotumours" as a result.

The researchers estimate that approximately 1% of patients who have metal-on-metal hip resurfacings develop pseudotumours within five years of treatment. A pseudotumour is 'a soft-tissue mass associated with the implant…neither malignant nor infective in nature', but that causes pain and discomfort to the patient.

Most worryingly for patients and doctors is that the causes of the tumours are unknown. The research discusses possible causes including 'toxic reaction to an excess of particulate metal wear debris.' The article stresses the need for further research to be done into the incidence of pseudotumours in patients who have had this treatment.

The paper concludes that the incidence of pseudotumours must be related to metal-on-metal hip resurfacing highlighting 'the need for regular clinical follow-up for new devices'. Such follow-up would follow NICE recommendations, but the current NHS climate makes this difficult, if not impossible, to achieve.

Read the research abstract

Notes

- The Journal of Bone and Joint Surgery - British Volume is a world leading orthopaedics journal with an Impact Factor of 1.868

- JBJS-Br publishes twelve issues a year of high-quality, peer-reviewed research, overseen by an international editorial board led by Editor James Scott

- The Journal was first published in 1948 by The British Editorial Society of Bone and Joint Surgery, a registered charity (No. 209299), with the object of the advancement and improvement of education in orthopaedic surgery and allied branches of surgery and the diffusion of knowledge of new and improved methods of teaching and practicing orthopaedic surgery in all its branches

- You can find out more about the Journal at http://www.jbjs.org.uk

Journal of Bone and Joint Surgery, British Volume

Link  http://www.orthosupersite.com/view.asp?rid=29416

By Gina Brockenbrough
July 2008

DENVER — Patients with foot and/or ankle surgical wounds who are taking COX-2 inhibitors may have a significantly higher incidence of delayed wound healing than those not taking the medication, according to new research presented here.

To evaluate the potential impact of COX-2 inhibitors on surgical wound healing, Chad Lamoreaux, MD, and colleagues performed a retrospective study of all foot and ankle patients operated on by a single surgeon using the same wound care plan during a 3-year period. The investigators excluded patients with pre-existing foot and ankle wounds and those with a history of chronic ulcers.

The results were presented at the American Orthopaedic Foot and Ankle Society 24th Annual Summer Meeting.

Of the 175 patients included in the study, 12.6% had delayed wound healing, which the investigators defined as a postoperative delay, infection, wound sloth or lesion that was followed for a period in the wound care clinic. Of the total study group, 18 patients were on preoperative standing doses of COX-2 medications, which included either celecoxib or rofecoxib.

The investigators discovered that nine of the 18 patients taking a COX-2 inhibitor had delayed wound complications compared to only 13 of the 157 non-COX-2 patients. While the groups were similar regarding demographics such as age and gender, a closer examination revealed a non-equal distribution of patients with diabetes and tobacco use.

After excluding patients with these risk factors, the investigators found that only six of the remaining 150 non-COX-2 patients had wound-healing complications (4%) compared to four out of the 13 remaining COX-2 patients (31%).

"[We] did make several assumptions to do this paper," Lamoreaux said during his presentation. "The distribution of Celebrex (celecoxib, Pfizer) vs. Bextra (valdecoxib, Pfizer) was not looked at. Also, the usage of the nonspecific anti-inflammatories was not looked at. But with the normal patients, our findings still showed a very significant impact of COX-2s on their ability to heal their surgical wounds."

For more information:

Lamoreaux C, Santrock RD and Deemer J. COX-2 inhibitors and wound healing complications. Presented at the American Orthopaedic Foot and Ankle Society 24th Annual Summer Meeting. June 26-28, 2008. Denver.
 

AAOS SAN FRANCISCO, March 7, 2008 - Some of the purported advantages of hip resurfacing over standard arthroplasty, though not all, seem to be real, researchers found in a randomized trial.

But other pluses in activity and function can probably be chalked up to patient selection bias and expectations, reported Martin Lavigne, M.D., of the University of Montreal, and colleagues, at the American Academy of Orthopaedic Surgeons meeting here.

In the randomized trial, patients who had hip resurfacing were significantly more likely to return to work and sports and had better step and hop test scores than standard arthroplasty patients did.

But functional scores and range of motion were no better than with hip replacement, the investigators found.

Hip resurfacing gained popularity with patients and some orthopedic surgeons on the basis of assumptions about better clinical function and ability to return to a high level of activity.

While retrospective cohort studies reinforced this perceived benefit, Dr. Lavigne said, "obviously there was a bias in the patient selection for hip resurfacing." Patients who sought hip resurfacing tended to be younger, more active, healthier, and expected a more active life after surgery, he said.

The newer procedure is still controversial among orthopedic surgeons despite rapid increases, commented Tom Schmalzried, M.D., of the Orthopaedic Hospital in Los Angeles, in a press conference where there was debate over the two approaches.

"The results of good, modern total hip replacement are really, really good," he said. "So for resurfacing to have a favorable risk-to-benefit ratio, you have to show you are getting something you don't get with total hip replacement."

For a more objective answer to this issue, Dr. Lavigne's group randomized 210 patients who were candidates for either procedure to undergo either uncemented 28-mm metal-on-metal total hip arthroplasty or hybrid metal-on-metal hip resurfacing.

All procedures were done by the same three surgeons with a posterior approach. Patients were informed which surgery they underwent only afterward.

Patients had a mean age around 50. Body mass index was higher in the total hip arthroplasty group.

Functional scores were slightly worse in the hip replacement group at six months (17 versus 11 on the WOMAC scale) but identical by two years (5 for both).

At six months after surgery, hopping on the affected leg was significantly easier for resurfacing group patients ("easy" or "very easy" 91.7% versus 78.9% and "difficult" or "impossible" 8.3% versus 21.1%, P=0.023).

Likewise, climbing stairs in a step test was easier at six months in the resurfacing group compared with the replacement group ("easy" or "very easy" 94.4% versus 76.3% and "difficult" or "impossible" 5.6% versus 23.7%, P=0.015).

Hip resurfacing group patients were also more likely to return to their prior work (96% versus 83%, P=0.02).

The young age of the patients made this an important outcome, Dr. Lavigne said.

Among the patients, 152 had data on activity level pre- and post-procedure.

Despite similar activity levels before surgery (P=0.22), more hip resurfacing than hip replacement patients returned to sports activities by one year after surgery (15% versus 7% high impact and 38% versus 28% moderate impact activity, P=0.022).

On a scale that included activities of daily living as well as sports, the difference tended to favor hip resurfacing but was not significant at one year (P=0.074).

"Both groups returned to a high level of activity," Dr. Lavigne said. "Hip resurfacing patients seem to be more active, but not as much as expected."

Type of surgery had no significant impact on what factors patients reported as limiting their return to sports activities, including implant protection, discomfort, fear of instability, and thigh pain.

Hip range of motion -- including total arc, arc of rotation, flexion-extension arc, and abduction-adduction arc -- was also similar for both groups among the 122 patients with data on this outcome (P>0.05).

Satisfaction with the procedure was uniformly high over time and across treatments.

While resurfacing is a more aggressive technique, Dr. Lavigne said, the rate of complications was similar between groups.

Long-term follow-up will be important to determine whether there are differences in need for revision between the procedures, he concluded.

Dr. Lavigne reported receiving research or institutional support from Zimmer, Stryker Howmedica, Biomet, DePuy, and Smith & Nephew and consulting for Zimmer.

Dr. Schmalzried reported receiving research or institutional support from Stryker, DePuy, Johnson & Johnson, Corin, and Wright Medical Technology; receiving miscellaneous funding from Stryker, DePuy, Johnson & Johnson, Corin, Wright Medical Technology, Zimmer, and Smith & Nephew; receiving royalties from Stryker, DePuy, Johnson & Johnson, Corin, and Wright Medical Technology; holding stock options in Stryker, DePuy, Johnson & Johnson, Corin, Wright Medical Technology, Zimmer, Biomet, Bristol-Myers Squib, and Pfizer; and being a consultant for Stryker.

Primary source: American Academy of Orthopaedic Surgeons meeting
Source reference:
Lavigne M, et al "Range of motion after hip resurfacing and THA: A single-blind randomized clinical study" AAOS meeting 2008; Abstract 058.

Additional source: American Academy of Orthopaedic Surgeons meeting
Source reference:
Lavigne M, et al "A randomized study comparing surface replacement arthroplasty to total hip arthroplasty" AAOS meeting 2008; Abstract 056.

Additional source: American Academy of Orthopaedic Surgeons meeting
Source reference:
Lavigne M, et al "Return to sports after hip resurfacing and total hip arthroplasty: A randomized clinical trial" AAOS meeting 2008; Abstract 053.

March 2008

SAN FRANCISCO -  A study indicates that having a metal-on-metal bearing surface and performing high-impact activities preoperatively may be positive predictors for participating in high-impact sports after total hip arthroplasty.

To determine which patients would participate in high-impact sports activity following total hip arthroplasty (THA) and to examine the factors linked to participation in these sports, David R. Marker, BS, and colleagues submitted pre- and postoperative questionnaires to 303 THA patients who had a mean follow-up of 3 years.

The investigators found that 30% of patients participated in at least one or more high-impact sport postoperatively for an average of 4.3 hours per week.

A regression analysis revealed that a preoperative high activity level and metal-on-metal bearing surface were the only statistically significant factors to predict participation in high-impact sports postoperatively. Moreover, while a comparison of patients participating in high- and low-impact sports revealed similar preoperative Harris Hip Scores, the investigators discovered that the high-impact sport participating patients had higher postop Harris Hip Scores.

"There are many patients participating in these high-impact sports, up to 30% in our cohort," Marker said during his presentation at the American Academy of Orthopaedic Surgeons 75th Annual Meeting, held here. "The preoperative participation, as well as the metal bearing surface, were found to be predictive of postoperative participation. We found [in] the short-term follow-up that the high-impact sports patients had similar and better outcomes."

For more information:

Marker DR, Seyler TM, Ulrich SD, et al. High-impact sports after THA: Is the bearing type and independent predictor of activity level? Paper #16. Presented at the American Academy of Orthopaedic Surgeons 75th Annual Meeting. March 5-9, 2008. San Francisco.

April 2008

Using potent anticoagulants such as low-molecular-weight heparin to prevent pulmonary embolism in total hip or knee arthroplasty patients, as recommended by the Chest Physicians Consensus Statement, may actually increase the risk of all-cause mortality compared to multimodal prophylaxis measures, according to a systematic literature review published in Clinical Orthopaedics and Related Research.

"We believe the American College of Chest Physicians should reconsider their guidelines to reflect the fact that PE (pulmonary embolism) occurs despite the use of potent anticoagulants and may, in fact, expose patients to increased mortality after surgery," the authors said in the study.

Nigel E. Sharrock, BMedSci, MB, ChB, and colleagues at the Hospital for Special Surgery, New York, conducted the systematic review, which included 20 English language studies published during the last 9 years. The researchers focused on studies that involved patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) and divided publications into three categories based on the venous thromboembolism prophylaxis regimen.

Specifically, Group A included the use of low-molecular-weight heparin, ximelagatran, fondaparinux or rivaroxaban, Group B included the use of a multimodal prophylaxis, and Group C included the use of warfarin.

"Multimodal prophylaxis (Group B) was defined as a protocol consisting of intention to use regional anesthesia (epidural or spinal) with or without intraoperative heparin during surgery or pneumatic compression and aspirin after surgery," the study authors noted.

The researchers found that the lowest number of deaths occurred among patients in Group B. Patients in Groups A and C were more than two times as likely to die compared to those in Group B, with no significant difference between Group A and Group C.

Patients in Group A also had a 60% to 70% higher risk of nonfatal PE compared to patients in Group B.

Nonfatal PE occurred in 94 of 15,839 patients in Group A (0.6%) vs. 25 of 7,193 patients in Group B (0.35%), according to the study.

"We show clinical PE occurs despite the use of powerful anticoagulants. The rate of 0.6% is comparable to the rate of 1% previously described with warfarin and low-molecular-weight heparin in cohort studies.

"This literature cannot support the use of powerful anticoagulants to prevent PE, although they clearly reduce the risk of venographically evident deep vein thrombosis," the study authors wrote.

For more information:

Sharrock NE, Gonzalez Della Valle A, Go G, et al. Potent anticoagulants are associated with a higher all-cause mortality rate after hip and knee arthroplasty. Clin Orthop Relat Res. 2008;466:714-721.

Glucosamine fails to ease hip arthritis Two-year study shows no improvement in pain or joint movement

February 19, 2008

Link MSNBC NEWS

Many people take glucosamine for arthritis-like symptoms but results of a new study suggest that glucosamine has no clinically meaningful effect on pain, function, or disease progression in patients with arthritis of the hip.

In a study lasting 2 years, Dr. Rianne M. Rozendaal and colleagues at the Erasmus Medical Center in Rotterdam, the Netherlands randomly assigned 222 patients to glucosamine (1500 milligrams daily) or to placebo. The patients had relatively early stages of the hip arthritis; about half of them had mild arthritis for a period of 3 years or less.

The research team took care to ensure the integrity of their results. The supplier of the glucosamine was required to double-check that the tablets were the correct dose, and all physicians, patients, and researchers were blinded to group assignment. The rate of completion was high (93 percent), and the study was conducted without drug company funding.

In spite of the carefully controlled trial conditions, treatment allocation (glucosamine or placebo) had no significant effect on pain scores, physical function, stiffness, use of pain medication, or progression of hip arthritis, Rozendaal's team reports in the Annals of Internal Medicine.

The writers of a commentary published with the study, note that despite numerous studies, definitive evidence of glucosamine's efficacy is lacking. They attribute much of the uncertainty to non-standardized glucosamine preparations, inadequate "blinding" in studies, and differences in outcome measures. MSNBC NEWS

A new surgical robot is making medical undergraduates three times more accurate during practice hip operations, according to pilot study to be discussed at a conference this week (8 February 2008).

Link News Website

 

Delegates at the British Society for Computer Aided Orthopaedic Surgery Conference will hear that results from a pilot study saw graduates 95 per cent more confident using this robotic technique than when using conventional surgical methods in training.

 

Professor Justin Cobb, Head of the Biosurgery and Surgical Technology Group at Imperial College London, conducted the trial on 32 undergraduate medical students at Imperial College London from December 2006 to December 2007. The pilot study tested whether planning before an operation, combined with the latest robotic navigation equipment could increase the success rates of students practising hip resurfacing arthroplasty procedures – a method for correcting painful hip bone deformities by coating the femoral head with a cast of chrome alloy.

Link http://www.medcompare.com/litupdate.asp?ArticleID=14960&typeid=24

1/1/2008

Journal: Clinical Orthopaedics and Related Research

Citation: 465:71-79, December 2007.

Authors: Carolyn Anglin, PhD, PEng; Bassam A Masri, MD, FRCSC; Jérôme Tonetti, MD; Antony J Hodgson, PhD, PEng; Nelson V Greidanus, MD, FRCSC

Femoral neck fracture is the most common short-term concern after hip resurfacing arthroplasty. Currently, there is little basis to decide between neutral and valgus placement. We loaded 10 notched cadaveric femur pairs to failure; one side was implanted at 0[degrees] relative to the femoral neck and the other at 10[degrees] valgus. All 20 were dual-energy xray absorptiometry-scanned. Failure load correlated with bone mineral density. Valgus placement increased the fracture load by an average of 28% over neutral for specimens with normal bone mineral density but had no effect on fracture load in specimens with low bone mineral density. For specimens with normal bone mineral density (typical of patients undergoing resurfacing arthroplasty), neutral-valgus placement had a greater effect than bone mineral density, explaining 54% of the fracture load variance. Component placement greater than 10[degrees] valgus is likely undesirable because this can lead to an increase in component size and a greater likelihood of notching. To reduce fracture risk, we recommend placing the femoral component in valgus and selecting patients with higher bone mineral density.

New Promising Data on S&N’s BIRMINGHAM HIP™ System

Link   http://www.ryortho.com/NEWSSHORTS/volume3/issue39/12-10-07-NS-New.htm

By Elizabeth Hofheinz, MEd, MPH December 10, 2007

No more wondering Down Under. The data is in. Smith & Nephew, Inc.’s Orthopaedic Reconstruction business is announcing the release of positive six-year clinical data by the Australian Orthopaedic Association National Joint Replacement Registry on the company’s BIRMINGHAM HIP Resurfacing System (BHR™). According to the company, the BHR, which has now been implanted in nearly 80,000 patients in 26 countries, conserves more of a patient’s bone than a traditional hip replacement, enabling younger, more active patients to undergo hip replacement surgery while preserving all future surgery options, including a primary hip replacement. The design of the BIRMINGHAM HIP Resurfacing System also offers patients a reduced risk of dislocation. The report revealed that the BHR device has the highest hip resurfacing system survivability rate among all of its established competitors for which data had been collected.

Included in the Australian report was the following information:

Since the inception of the registry, the BIRMINGHAM HIP Resurfacing System has been the overwhelming choice of patients—over 75% of resurfacing procedures have used the BHR device.

The BHR System has a revision rate of 0.8 per 100 component years or 2.5%.

The BHR System’s rate is derived from 19,585 component years, 19 times that of any other resurfacing competitor.

Three alternative hip resurfacing systems were cited for their high revision rates.

According to the registry, hip resurfacing accounts for 7.9% of all primary hip replacements.
Commenting in the news release was Joseph DeVivo, President of Smith & Nephew Orthopaedic Reconstruction: “We are extremely pleased with the Registry’s results. The report once again highlights the ability of the BIRMINGHAM HIP Resurfacing System to help people maintain the most active and healthy lifestyle possible. The BIRMINGHAM HIP Resurfacing System lets active people live the life they love and continue to pursue their passions. The long-term clinical data available clearly demonstrates the benefits of the BIRMINGHAM HIP Resurfacing System, which is the gold standard for resurfacing technology in the world and a significant addition to our reconstructive product portfolio in the United States.”

The Registry evaluates the timing and reasons for revision surgery as well as mortality rates, and it measures the success rates of products and procedures across Australia. This year’s report is based on the analysis of 332,700 hip and knee procedures undertaken in 271,188 patients from September 1999 through December 31, 2006.

According to the company, the study is highly regarded for its comprehensiveness and accuracy because the Registry is able to obtain a near-complete set of data relating to hip and knee joint replacement for an entire country. The Registry receives information from all public and private hospitals undertaking joint replacement. Using a strict validation process and following retrieval of unreported records and checking of unmatched data, the initial validation for the 2005/6 Registry data resulted in over 96% of Registry records verified against health department data.