Total hip resurfacing, using an FDA approved system being used for its approved labeled indications, meets primary coverage criteria for effectiveness and is covered as an alternative to total hip replacement in patients who are candidates for total hip replacement and who are likely to outlive a traditional prosthesis.  

 

The use of a hip resurfacing system that does not have PMA or 510(k) FDA approval is not covered based on benefit certificate primary coverage criteria that there be scientific evidence of effectiveness.

 

For contracts without primary coverage criteria, total hip resurfacing, using an FDA approved resurfacing system being used for its approved labeled indications, is covered as an alternative to total hip replacement in patients who are candidates for total hip replacement and who are likely to outlive a traditional prosthesis.  Any use of a resurfacing system without a FDA PMA or 510(k) approval is considered investigational and is not covered.  Investigational services are  exclusions in the member benefit contract.

 

 

In 1996, Schmalzried and colleagues reported on the initial experience of metal-on-metal total hip resurfacing in 21 hips and 19 patients. Two different types of prostheses (4 Wagner and 17 McKinn) were used. The acetabular components of the McKinn prosthesis showed progressive loosening. Based on these results, the investigators developed new design and implantation techniques leading to the Conserve®Plus device. This same group of investigators is now involved in the clinical trial of the Conserve®Plus device.

 

Review of the peer-reviewed literature identified additional articles. Amstutz and colleagues reported on 355 patients who received 400 metal-on-metal surface arthroplasties using the Conserve Plus device with a follow-up of 2–6 years.  Of the 355 patients, 54% had University of California Los Angeles activity scores greater than 7; and at 4 years, 94.4% of components survived per Kaplan-Meier survivorship curves. Revision of the surface arthroplasty to total hip replacement occurred in only 12 (3%) hips. Beaule and colleagues reported on metal-on-metal surface arthroplasty in 56 patients with Ficat stage III and IV osteonecrosis.  Only 2 hips required total hip replacement during follow-up of an average of 4.9 years. While these study results are promising, the authors noted need for further evaluation to determine appropriate patient selection criteria and the most beneficial techniques for femoral bone preparation and fixation.

 

Some outcomes have been reported with the Birmingham hip resurfacing device suggesting medium to long-term durability. Treacy and colleagues reported the 5-year survival of Birmingham hip resurfacing arthroplasty in 144 patients was 98% overall.  Failure of the femoral component occurred in 3 cases within the first 2 years of the study (2 infections and 1 fracture) in the Treacy study. Shimmin and Back reviewed 3,497 Birmingham hip resurfacings performed by 89 surgeons between April 1999 and April 2004.  The authors reported the incidence of femoral neck fracture was 1.46% (50 of 3,497) and the mean time to fracture was 15.4 weeks. Glyn-Jones and colleagues evaluated the stability of Birmingham hip resurfacing arthroplasties by radiographic analysis in 22 hips in 20 patients.  At 24 months, migration of the head of the femoral component was not statistically significant (0.2 mm total three-dimensional).

 

In support of the application for FDA premarket approval, clinical data on 2,385 Birmingham Hip resurfacings performed by a single surgeon in the United Kingdom was presented to the FDA Orthopaedic and Rehabilitation Devices Panel (Panel) in September 2005. Of the 2,385 cases, 27 revisions were required including 10 revisions due to femoral neck fracture, 6 for femoral head collapse, 1 for dislocation, 2 for avascular necrosis, and 8 for infections.

 

Though the Birmingham hip resurfacing device has been granted a PMA by the FDA, there still are ongoing questions about the intermediate and long-term durability of this device compared with standard hip arthroplasty. There also are continued questions about short-term revisions (due to femoral neck fracture) and also potential concerns about shedding of metal particles.

 

In February 2007, a Blue Cross Blue Shield Association Technology Evaluation Center (TEC) Assessment reviewed evidence published through January 2007 on metal-on-metal total hip resurfacing.  The Assessment evaluated studies of individuals with advanced degenerative joint disease of the hip who received a hip resurfacing (HR) device and that reported data on short- and long-term clinical outcomes, including benefits and harms, as an alternative to total hip replacement (THA). The TEC identified one randomized controlled trial,  and 12 uncontrolled series.  For the Assessment, these published trials, the FDA PMA submission data, and information from the Australian Orthopedic Association (AOA) National Joint Replacement Registry  were evaluated.

 

In the randomized controlled trial (100 patients in each group), the HR device was implanted in patients who were younger (49 to 51 years old) and had a smaller body mass index (17 to 49 kg/m2) than those who usually undergo THA (>=65 years old), and the majority comprised male patients (63% to 68%) who were being treated for advanced osteoarthritis (75%).  In comparison to THA, the perioperative differences demonstrate that HR reduced the surgical time (p<0.001), decreased the hospital stay (5 vs. 6.1 days), and used a longer incision (p<0.001). Both groups had a similar incidence of complications; with 2 deep vein thromboses per group, and 2 THA patients had deep infections without recurrence. At 12 months’ follow-up, 2 patients in the THA group required revision for femoral head aseptic loosening at 6 and 9 months, respectively, and none experienced femoral head fracture. Both groups showed substantial improvement over preoperative status on functional outcomes measures and reported satisfaction or very high satisfaction scores (98%).

 

The 12 published series reporting clinical outcomes after HR included a total of 2,076 patients (71% male) who ranged in mean age from 34 to 57 years. Although most patients had advanced osteoarthritis (80%), some studies enrolled patients with femoral head osteonecrosis  and/or developmental hip dysplasia, and only 3 used the FDA-approved Birmingham device. Mean follow-up was approximately 3 years, but ranged from less than 1 year  to 12 years,  and the proportion of enrolled patients available at follow-up was generally 90% to 100%, but as low as 22%.  Of the 2,076 patients treated with HR, 57 (2.7%) required revision to THA, most for femoral neck fracture or component loosening; the proportion of cases that required revision ranged from 0.3% to 22%.

 

Although the 12 published series exhibit little consistency in outcomes measures used, the aggregate data suggest that HR-treated patients who do not require a revision have substantial symptomatic improvement of pain and hip function over presurgical status. Moreover, HR patients report substantial activity levels and returning to playing sports after treatment.

 

The TEC also evaluated the patient safety and effectiveness data considered for the FDA submission of the Birmingham device from the McMinn Cohort, which are supported by unpublished data on 3,374 hips implanted by 140 surgeons and published reports on more than 3,800 hips treated by multiple surgeons (Worldwide Cohort).

 

The McMinn Cohort included 71% men and 29% women, ranging in age from 13 to 86 years (average, 53 years). The predominant diagnoses for treatment were advanced osteoarthritis (75%), dysplasia (16%), avascular necrosis (4%), inflammatory arthritis (2%), and “other” (3%). The Worldwide Cohort was reportably comparable. At the 5-year follow-up, a total of 76 revisions to THA were reported (2.26%), resulting from events similar to those reported for the McMinn Cohort.  In addition, results of the Oswestry-Modified Hip Scores for both cohorts showed improvement at 5 years from a baseline mean of 60.1 to 94.8 (58%). With regard to long-term safety, literature summaries provided to the FDA demonstrated increased serum and urinary concentrations of metal ions postoperatively in patients with THA, particularly after metal-on-metal procedures, but data show no conclusive evidence of significant detrimental effects.

 

The AOA registry’s annual report for 2006 is based on 92,210 primary THAs, including 84,872 primary THAs, 7,205 metal-on-metal HRs, and 133 thrust-plate procedures.  Some of these data may include patients reported in the Worldwide Cohort. In general, resurfacing procedures were used more often in men than women (73% vs. 56%) and in younger patients (90% <65 years) than primary THA. At 5 years’ follow-up, conventional THAs showed fewer revisions (1.7%) than HRs (2.2%), but THA prostheses may not be reflected, and no patient demographic characteristics were available for comparison.

 

The TEC concluded that use of the FDA-approved metal-on-metal HR devices meets the Blue Cross Blue Shield Association Technology Evaluation Center criteria as an alternative to THA in patients who are candidates for THA and who are likely to outlive a traditional prosthesis. The available evidence shows that HR short-term symptomatic and functional health benefits are at least as good as those of THA over midterm follow-up, with no substantial differences in revision rates, among patients younger than 65 years who are likely to outlive a traditional prosthesis. Also, inference from the available long-term evidence suggests that HR will be at least as beneficial as THA in patients who are likely to outlive a traditional prosthesis, based on 1) appropriate patient selection, 2) the fact that HR is a bone-conserving procedure that preserves the femoral head and stock largely intact, and 3) substantial 5-year follow-up of device survival.

 

There is minimal published medical literature regarding total hip resurfacing using polyethylene components.

 

2008 Update

Mont et al (2006) described the results of the FDA-approved Investigational Device Exemption (IDE) prospective, multicenter trial of the Conserve Plus hip resurfacing system. The investigators identified a number of risk factors for complications after the first 292 procedures; these included the presence of cysts, poor bone quality, leaving reamed bone uncovered, minimizing the size of the femoral component to conserve acetabular bone, and malpositioning of the acetabular shell. Modification of inclusion criteria and surgical technique in the next 906 patients (1,016 hips) resulted in a decreased rate of femoral neck fracture (from 7% to <1%). There was also a trend toward reduction in other types of complications (e.g., nerve palsy was reduced from 4.1% to 2.2% and loosening of the acetabular cup from 3.4% to 1.9%). No differences between the two cohorts were observed in the Harris hip score (93 vs. 93) or the SF-12

 

An updated search of the MEDLINE database for the period of May 2008 through October 2009 identified 2 qualitative systematic reviews, 2 randomized controlled trials comparing THR with large-diameter head THA and other publications concerning factors in survival such as patient selection criteria and the surgeon’s learning curve.

 

One of the systematic reviews compared outcomes from THR and THA in studies with short- to mid-term follow-up (Marker, 2009). The 7 comparative studies that assessed return to sports and activity showed either similar outcomes for the two procedures or advantages for the THR group. Three additional studies assessed gait, and 1 study was identified that assessed postural balance; all 4 showed similar or better outcomes for THR than THA. Two studies were discussed that compared the outcomes of conversion of failed THR to THA with primary THA. One of the 2 studies was reviewed above (Ball, 2007). The second was a 2009 report that compared outcomes of 39 patients whose resurfacing was converted to THA with a group of primary THA patients that had been matched by gender, age, body mass index (BMI), and preoperative Harris hip score; all procedures had been performed by the same surgeon (McGrath, 2009) Perioperative measures were similar except for the mean operating time, which was 19 minutes longer for the revision group. At an average 45 months follow-up, the mean Harris hip scores were similar for the 2 groups (score of 92 for conversion to THA and 94 for primary THA).

 

In 2008, Queseda, Marker and Mont published a qualitative systematic review that focused on advantages and disadvantages of THR in comparison with THA (Quesada, 2008).  Advantages were reported to include possible bone conservation on the femoral side, lower dislocation rates, more range-of-motion, more normal gait pattern, increased activity levels, increased ease of insertion with proximal femoral deformities or retained hardware, and straightforward revision. Possible disadvantages of resurfacing were reported to be increased difficulty to perform the procedure, increased acetabular bone stock loss, femoral neck fractures, and the effects of metal ions. Although prospective controlled studies with long-term follow-up are needed for conclusive evaluation of these issues, the literature reviewed by these investigators suggests an increased risk of femoral neck fractures in post-menopausal women and smallboned men. Queseda et al. conclude that THR is most appropriate in young (less than 60 years) active men.

 

For a 2009 report on patient selection criteria for THR, Nunley and colleagues reviewed 207 publications, the majority of which they found to have little or no description of the patient population, small sample sizes, poor study design, limited control of bias, and inadequate statistical analysis (Nunley, 2009). The literature showed no clear consensus on the upper age limit for male patients, but the most commonly used criteria was age younger than 65 years. Nine articles suggested that female patients should be cautiously evaluated before performing hip resurfacing, especially if they are postmenopausal or have decreased bone mineral density. Some of the data reviewed was from the Australian joint replacement registry, where women 65 or older were observed to have a revision rate of 11% at 4 years. This was compared with men younger than 55 years of age who had a revision rate of less than 2%. Both of these cohorts (older women and younger men) have revision rates of 2% after THA. The evidence reviewed by Nunley et al. also indicates that obesity, defined as BMI > 35 kg/m2 can be viewed as a relative contraindication to THR, but not THA. Femoral head cysts, head-neck junction abnormalities, and poor bone density may also be considered risk factors for implant failure. The literature on metal sensitivity and the presence of aseptic lymphocytic vasculitis-associated lesions (ALVAL) is evolving, and the potential for transplacental transfer of metal ions is a concern for young female patients who have the potential to become pregnant in the future. The authors concluded that the best candidates for hip resurfacing are men under age 65 with osteoarthritis and relatively normal bony morphology.

 

Two randomized controlled trials were published in 2009 that randomized patients to THR or THA with a large diameter metal-on-metal implant (Lavigne, 2009) (Garbuz, 2009). The study by Lavigne et al. tested the hypothesis that the observed improvement in activity with THR is due either to patient selection bias or to the larger femoral head with THR.  In order to test this hypothesis, 48 patients were randomized to either THR or largehead THA. The patients and the evaluators at the gait laboratory were kept blinded to the type of arthroplasty until 1 year after surgery. There were no differences between the two groups for the majority of measures at 3, 6, and 12 months after surgery. Specifically, similar results were observed for normal and fast walking, postural evaluations, timed up and go test, hop test, hip flexor and abductor strength ratio. The THR group performed better during the functional reach test, and the THA group completed the step test 3 seconds faster than the THR group. The WOMAC, SF-36, Merle d’Aubigne, and UCLA activity scores were similar in the 2 groups. Garbuz and colleagues randomized 107 patients to THR or large-head metal-on-metal THA.  There was no difference in WOMAC or SF-36 scores for the 73 patients who had been followed for at least 1 year. However, for the subset of patients who had been tested for serum levels of cobalt and chromium, cobalt was 10-fold higher and chromium was 2.6 fold higher in the large head metal-on-metal THA group than the THR group. This was a 46-fold increase from baseline in serum cobalt and a 10-fold increase from baseline in serum chromium for the largediameter head THA group, possibly related to particulate wear at the head-neck junction. Both of these studies support the hypothesis that the improved activity observed in THR patients is due to the larger diameter components used in resurfacing.

 

The increase in serum cobalt and chromium ions with metal-on-metal THR remains a concern. One retrospective study of 610 consecutive hip resurfacings (120 with more than 5-year follow-up) reported that failure was possibly related to metal debris on 0.5% of THRs (Steffen, 2008).  However, after examining histological samples taken at the time of revision, Olivere and colleagues concluded that the rate of metallosis-related revision in their series of 463 consecutive patients was 3% at 5 years(Ollivere, 2009).  All of the patients in this series had been recruited into the local arthroplasty follow-up program at the time of the primary surgery; 437 (94%) returned for clinical and radiological follow-up with a mean follow-up of 43 months (range, 6-90 months). Case notes, radiographs, and magnetic resonance scans were available for the 13 revisions (2.8%, 12 patients). Histological findings were available for 12 cases, and were rereviewed by a histopathologist with experience in metal wear and debris. In 7 cases, the histological findings were consistent with a response to metal wear debris. Survivorship analysis gave an overall survival rate of 95.8% at 5 years, with an end-point survival of 96.9% at 5 years for metallosis requiring revision. The relative risk for female gender in the metallosis group was 4.94. Also associated with metallosis were a smaller femoral component, greater abduction angle, and a higher BMI.

 

Other studies suggest a high learning curve for THR related to the increased difficulty in accessing the acetabular compartment. For example, in one study most of the failures were related to early acetabular loosening (Kim, 2008).  A report by Nunley et al. suggests that for experienced hip surgeons the learning curve for avoiding early complications (e.g., early femoral fracture) is 25 cases or less, but the learning curve for achieving the desired component positioning is 75-100 cases or more (Nunley, 2009).  Steeply inclined component positioning along with a small size of component have been shown to be associated with metal ion levels, possibly due to an increase in edge loading (De Haan, 2008).

 

A search of the literature on resurfacing for osteonecrosis identified a number of articles, including a 2005 review and a 2009 study on the topic (Grecula, 2005) (Stulber, 2009).   Both articles discussed comparisons of hemi-resurfacing to THR, referencing a single comparative study by Beaule from 2004; thus, it is unlikely that additional comparative resurfacing studies have been published since 2004 (Beaulé). This literature shows total resurfacing/replacement to provide more consistent and better initial pain relief than partial resurfacing. The increase in poor outcomes with resurfacing is believed to be related to continued abrasion and possible misfit of the femoral component against the native acetabular cartilage. Therefore, for osteonecrosis in younger patients who do not have contraindications for the metal-on-metal prosthesis, total hip resurfacing (femoral and acetabular implant) would be preferred over a femoral component alone.

 

The evidence available at this time supports the conclusions reached above that hip resurfacing (partial or total) presents an effective alternative for active patients who are considered too young for THA, when performed by surgeons experienced in the technique. The literature on risk factors for metallosis and implant failure is evolving as longer follow-up becomes available. Emerging evidence indicates an increased risk of failure in women due to decreased bone strength and increased risk of metal sensitivity.

 

Therefore, these risk factors should be considered in the overall patient evaluation for total hip replacement.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In a series of 447 patients younger than 50 years of age, implant survival in women was 96.1% at 10 years and 91.2% at 14 years, compared with 100% for men at both 10 and 14 years (Matharu, 2013).  Female gender (p=0.047) and decreasing femoral head size (p=0.044) were significantly associated with an increased risk of revision. Analysis of 162 patients 65 years of age or older found 10-year survival of 98.9% in men and 91.9% in women (Pailhe, 2014). Implant survival was negatively associated with increasing age (p=0.014) and decreasing femoral head size (p=0.024), with a nonsignificant trend for a negative association with female gender (p=0.079).

 

In 2014 the United Kingdom’s National Institute for Health and Care Excellence (NICE) issued an updated technology guidance on THA and THR for end-stage arthritis of the hip (NICE, 2014). NICE concluded that both THA and THR are options for treating end-stage arthritis of the hip, although clinicians may be more likely to offer resurfacing arthroplasty to men than to women because higher revision rates have been observed in women. The appraisal committee concluded that THA was more effective and less costly than THR in all analyses, that revision rate was the most important key driver of costs and quality-adjusted life years, and that because the predicted revision rate of THA was less than 5% at 10 years in the population for whom both THA and THR were suitable, the revision rate standard for THR should be the same as that for THAs. NICE recommends specific prostheses for THA and THR only if the prostheses have revision rates of 5% or less at 10 years.

 

 

 

 

 

 

 

A literature search conducted through August 2017 did not reveal any new information that would prompt a change in the coverage statement.  

 

A literature search was conducted through August 2018.  There was no new information identified that would prompt a change in the coverage statement.