HR Issues

Study: Surface replacement arthroplasty may offer advantages over THA

Canadian investigators said hip resurfacing resulted in greater patient activity after 2 years.

By Robert Trace
1st on the web (September 19, 2007)
September 2007

SEOUL — Total hip arthroplasty is an established procedure with well-documented complication rates and clinical results, but surface replacement arthroplasty may offer additional clinical benefits to many patients, according to a group of Canadian researchers.

"We decided in 2003 to do a comparative study of hip resurfacing, or surface replacement arthroplasty (SRA), to the gold standard of total hip arthroplasty (THA), since we were not aware of any direct prospective studies out there comparing the two procedures," said Pascal-André Venditolli, MD, of the Maisonneuve-Rosemont Hospital in Quebec.

He and his colleagues randomly assigned 210 hips to receive uncemented metal-on-metal THA (103 hips) or a hybrid metal-on-metal SRA (107 hips). All surgeries were performed by three orthopedic surgeons, who used a posterior approach.

The researchers prospectively collected perioperative and postoperative data, and analyzed the clinical data for a minimum of 2 years.

Postop complications included three isolated traumatic dislocations and one recurrent dislocation in the THA group, which required acetabular cup revision. Two SRAs required revision for late head collapse. No postop femoral neck fractures occurred in the SRA group, he said.

There was one case of loosening at 6 months postop in the resurfacing group, which had shifted varus. There were also two cases of deep venous thrombosis in both patient groups, he said.

Although the investigators did not report a significant difference in surgical time between the two procedures, patients' length of stay in the hospital was significantly shorter for the SRA group compared to the THA patients — 5 days vs. 6.1 days for the THA group (P=.001).

"There was also a significant difference in return to work: 96% of the SRA patients returned to their previous work within 1 year vs. 83% in the THA group," Venditolli said.

Although patients in both groups demonstrated a high satisfaction rate and achieved similar WOMAC and Merle d'Aubigné functional scores, "SRA patients had better UCLA activity scores (7.1 vs. 6.3; P=.037) and returned to heavier activities (P=.035)" after 2 years, he said.

"This randomized study shows that SRA and THA present a similar complication rate, but distinctive complications," Venditolli said. "It also suggests that SRA results in better function and improved patient activity in comparison to THA.

"However, the effect of long-term fixation related to increased activity levels is unknown. Long-term follow-up is necessary to determine the survivorship of SRA over THA," he said.

For more information:

Vendittoli P-A, Lavigne M, Lusignan D, Roy A-G. A randomized study comparing surface replacement arthroplasty to total hip arthroplasty: 2-4 years follow-up. F028-2. Presented at the 15th Triennial Congress of the Asia Pacific Orthopaedic Association. Sept. 9-13, 2007. Seoul.

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Comparative Arthroplasty Alternatives for the Young Arthritic
By Thomas P. Schmalzried, MD
ORTHOPEDICS 2007; 30:756
September 2007

Thomas P. Schmalzried

Hip resurfacing is embraced by patients. In principle, the attraction is similar to smaller incisions: patient satisfaction is related to the degree of invasion of their body.

Hip resurfacing is driven by the Internet, with an Internet pro-resurfacing culture perceiving total hip replacement (THR) as an older technology and an older person’s operation. This perspective is fueled by the historical risk of dislocation, traditional activity restrictions, and concerns of component loosening with bone loss leading to morbid revision THR. There is a paucity of patient awareness regarding the outcomes of current-generation THR. In fact, there is a paucity of studies comparing current-generation THR and total resurfacing.

Indications for Total Hip Resurfacing
Total resurfacing and THR are not directly competing technologies. The indications for hip resurfacing are more limited. Not all patients who are candidates for THR are good candidates for resurfacing .

Categorically, total hip resurfacing should be considered for those patients at increased risk for failure of THR. Historically, such patients are young and healthy, with men being at greater risk than women. Patients who have been told they are too young for THR have embraced resurfacing. The operative parameters for conversion of a failed resurfacing to THR are similar to those for a primary THR.(1)

With current technology, the acetabular component size and position are essentially the same for total resurfacing and THR.2 The issues are on the femoral side and include:

Bone Density. The risk of femoral neck fracture following resurfacing is related to bone density, with an increased risk in women and men >65 years.3,4
Head-to-Neck Ratio. Because resurfacing occurs around the femoral neck, it is technically helpful to have a head-to-neck ratio >1.2.
Femoral Offset and Limb Length. With resurfacing, femoral offset and limb length cannot be changed to a practically significant degree; therefore, these parameters should be close to normal (>120° neck-shaft angle and limb-length difference within 1 cm).2
Focal Defects. Because focal defects undermine support for the component, large necrotic segments or cystic defects are undesirable.5
Hips that have all 4 of these criteria are arthritic hip grade (AHG) A, which is basically a normal hip with no cartilage. Grade B hips lack 1 factor, grade C hips lack 2 factors, and grade D hips lack 3 factors.6

Clinical Results

In our series of more than 350 consecutive total hip resurfacings(7),  there have been no femoral neck fractures. After a 2-year minimum follow-up, AHG was significantly associated with preoperative Harris Hip score (A>B>C), occurrence of mild to moderate postoperative pain (A<B & C), and hip range of motion. In other words, hips with a lesser degree of secondary arthritic changes had a higher AHG and a better outcome. The mean UCLA activity score was 8.2, but activity scores were higher for higher hip grades. These data support the selection criteria and also support relatively early intervention.

During the same period, we compared our first 50 consecutive hip resurfacings in 50 patients to 44 THRs performed in 35 patients.7 Surgeries were performed by the same surgeon using a posterior approach. The same postoperative protocol was followed in both groups with no activity restrictions; minimum follow-up was 2 years.

As one might expect, there were differences between the two groups. Average age was 46 years for resurfacing patients versus 55 years for THR patients. Resurfacing patients were predominantly men and taller, and had a lower body mass index.

Resurfacing patients had a lower preoperative Harris Hip score (ie, reported more pain), but they had a higher preoperative UCLA activity score and greater preoperative range of motion. The resurfacing patients had a lower mean ASA score (ie, better general health).

On average, it took 18% longer to perform the surface replacements than the THRs. However, total blood loss was 250 cc lower with the resurfacings (despite a larger exposure), probably because there was no femoral canal violation or bleeding. Less transfusions were given in the resurfacing group because of the lower blood loss and the better general health status of the patients. There was no significant difference in the length of hospital stay between the two groups.(7)

With regard to outcomes, hip resurfacing patients had the same 2-year Harris Hip score (97 versus 96). Hip resurfacing patients had greater functional improvement, resulting in a greater increase in the Harris Hip score. The resurfacing patients also had a greater increase in UCLA activity score and a higher postoperative SF-12 physical score. There was no difference between the groups in postoperative range of motion. In fact, the THR group had greater improvement. There was one dislocation in each group.

The bottom line is both technologies performed very well in our series. Because patient characteristics are the main determinant of outcome, we must be careful with simple technology-based comparisons.(7)

References 1. Ball ST, Le Duff MJ, Amstutz HC. Early results of conversion of a failed femoral component in hip resurfacing arthroplasty. J Bone Joint Surg Am. 2007; 89:735-741.
2. Silva M, Lee KH, Heisel C, Dela Rosa MA, Schmalzried TP. The biomechanical results of total hip resurfacing arthroplasty. J Bone Joint Surg Am. 2004; 86:40-46.
3. Shimmin AJ, Back D. Femoral neck fractures following Birmingham hip resurfacing: a national review of 50 cases. J Bone Joint Surg Br. 2005; 87:463-464.
4. Australian Orthopaedic Association National Joint Replacement Registry 2006. Available at: www.dmac.adelaide.edu.au/aoanjrr/ .
5. Amstutz HC, Beaule PE, Dorey FJ, Le Duff MJ, Campbell PA, Gruen TA. Metal-on-metal hybrid surface arthroplasty: two to six-year follow-up study. J Bone Joint Surg Am. 2004; 86:28-39. 7. Fowble VA, dela Rosa MA, Schmalzried TP. A comparison of total hip resurfacing and total hip replacement patients and outcomes. Clin Orthop Relat Res. In press.

Correspondence should be addressed to: Thomas P. Schmalzried, MD, Joint Replacement Institute at St Vincent Medical Center, S. Mark Taper Bldg, 2200 W Third St, Ste 120, Los Angeles, CA 90057.

Comparative Arthroplasty Alternatives for the Young Arthritic READ COMPLETE ARTICLE

 

Estimates of Healthcare-Associated Infections

CDC strives to understand how healthcare-associated infections happen and to develop appropriate interventions. A new report from CDC updates previous estimates of healthcare-associated infections. In American hospitals alone, healthcare-associated infections account for an estimated 1.7 million infections and 99,000 associated deaths each year. Of these infections:

• 32 percent of all healthcare-associated infection are urinary tract infections
• 22 percent are surgical site infections
• 15 percent are pneumonia (lung infections)
• 14 percent are bloodstream infections

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Osteonecrosis Of The Femur - Hip Resurfacing Surgery, Alternatives to Hip Replacement
By Alampallam Venkatachalam

 

Osteonecrosis is a condition due arising from a diminution of blood supply to bone. It affects most importantly the upper end of the femur. If left untreated it progresses to bony collapse and arthritis. The causes are many like alcohol abuse, steroid intake, Caisson's disease, Gaucher's disease.

 

The patient can experience sudden pain in the hips which radiates to the knee and can be confused for knee pain. Gait is painful. In early cases, x- rays are negative and MR scans are diagnostic. Treatment in the early stages is controversial and there are no clear guidelines.

 

Prolonged bed rest and crutch walking have not been shown to relieve pain or halt progression of the disease.

 

Treatment in late cases

 

Core decompression does ameliorate symptoms. It is minimally invasive and does not involve a replacement. If it fails then a replacement is possible at a later date.

 

Treatment in late cases with advanced destruction

 

Treatment is by a total hip replacement if bony destruction is extensive. A partial or total surface hip replacement is done if destruction is confined to the surface cartilage alone. Since it occurs in young individuals, a Surface Hip replacement is a better option as it conserves bony stock and a total hip replacement can still be done at a later date. Resurfacing of the hip is restricted to those cases of osteo necrosis where the amount of destruction is less than 30 percent of the head. Where it exceeds thirty percent, a new type of hip prosthesis called the Proxima hip is available in Chennai. This Proxima hip is an uncemented metal on metal large diameter bearing. It has been performed for avascular necrosis and other conditions like ankylosing spondylitis, post traumatic arthritis following acetabular fracture. Vascularised fiblar graft is done with the help of a microvascular surgeon.

 

The author trained with eminent Hip experts in Cambridge, Manchester and Livepool. He performs Hip replacements, Hip resurfacing, Proxima hip replacements, Osteotomies, Fracture fixation, Core decompression, Birmingham replacements at Bharathiraja hospital. Visit http://www.hipsurgery.in and http://www.kneeindia.com Contact him at 00 91 9282165002

 

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2007-09-19 22:47:00

Nanotechnology diamond ice coatings could improve knee prostheses and solar cells

There is a huge demand for medical implants for almost every body part you can think of. As we have reported here before, the market for medical implant devices in the U.S. alone is estimated to be $23 billion per year and it is expected to grow by about 10% annually for the next few years. Implantable cardioverter defibrillators, cardiac resynchronization therapy devices, pacemakers, tissue and spinal orthopedic implants, hip replacements, phakic intraocular lenses and cosmetic implants will be among the top sellers. Current medical implants, such as orthopedic implants and heart valves, are made of titanium and stainless steel alloys, primarily because they are biocompatible. Unfortunately, in many cases these metal alloys with a life span of 10-15 years may wear out within the lifetime of the patient. With recent advances in industrial synthesis of diamond and diamond-like carbon film bringing prices down significantly, researchers are increasingly experimenting with diamond coatings for medical implants. On the upside, the wear resistance of diamond is dramatically superior to titanium and stainless steel. On the downside, because it attracts coagulating proteins, its blood clotting response is slightly worse than these materials and the possibility has been raised that nanostructured surface features of diamond might abrade tissue. That's not something you necessarily want to have in your artificial knee or hip joints (although some of the currently used implant materials cause problems as well). Researchers have now run simulations that show that thin layers of ice could persist on specially treated diamond coatings at temperatures well above body temperature. The soft and hydrophilic ice multilayers might enable diamond-coated medical devices that reduce abrasion and are highly resistant to protein absorption.

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Study: Surface replacement arthroplasty may offer advantages over THA

Canadian investigators said hip resurfacing resulted in greater patient activity after 2 years.

By Robert Trace
1st on the web (September 19, 2007)
September 2007

SEOUL — Total hip arthroplasty is an established procedure with well-documented complication rates and clinical results, but surface replacement arthroplasty may offer additional clinical benefits to many patients, according to a group of Canadian researchers.

"We decided in 2003 to do a comparative study of hip resurfacing, or surface replacement arthroplasty (SRA), to the gold standard of total hip arthroplasty (THA), since we were not aware of any direct prospective studies out there comparing the two procedures," said Pascal-André Venditolli, MD, of the Maisonneuve-Rosemont Hospital in Quebec.

He and his colleagues randomly assigned 210 hips to receive uncemented metal-on-metal THA (103 hips) or a hybrid metal-on-metal SRA (107 hips). All surgeries were performed by three orthopedic surgeons, who used a posterior approach.

The researchers prospectively collected perioperative and postoperative data, and analyzed the clinical data for a minimum of 2 years.

Postop complications included three isolated traumatic dislocations and one recurrent dislocation in the THA group, which required acetabular cup revision. Two SRAs required revision for late head collapse. No postop femoral neck fractures occurred in the SRA group, he said.

There was one case of loosening at 6 months postop in the resurfacing group, which had shifted varus. There were also two cases of deep venous thrombosis in both patient groups, he said.

Although the investigators did not report a significant difference in surgical time between the two procedures, patients' length of stay in the hospital was significantly shorter for the SRA group compared to the THA patients — 5 days vs. 6.1 days for the THA group (P=.001).

"There was also a significant difference in return to work: 96% of the SRA patients returned to their previous work within 1 year vs. 83% in the THA group," Venditolli said.

Although patients in both groups demonstrated a high satisfaction rate and achieved similar WOMAC and Merle d'Aubigné functional scores, "SRA patients had better UCLA activity scores (7.1 vs. 6.3; P=.037) and returned to heavier activities (P=.035)" after 2 years, he said.

"This randomized study shows that SRA and THA present a similar complication rate, but distinctive complications," Venditolli said. "It also suggests that SRA results in better function and improved patient activity in comparison to THA.

"However, the effect of long-term fixation related to increased activity levels is unknown. Long-term follow-up is necessary to determine the survivorship of SRA over THA," he said.

For more information:

Vendittoli P-A, Lavigne M, Lusignan D, Roy A-G. A randomized study comparing surface replacement arthroplasty to total hip arthroplasty: 2-4 years follow-up. F028-2. Presented at the 15th Triennial Congress of the Asia Pacific Orthopaedic Association. Sept. 9-13, 2007. Seoul.

READ COMPLETE ARTICLE