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Biomet
 
 

Dear Surgeon:

Biomet is committed to ongoing post-market surveillance of its products, including its metal-on-metal (MoM) hip devices. Consistent with this commitment and to act appropriately and responsibly in the interest of patient welfare, Biomet has been closely monitoring the available data regarding its MoM hip devices. This letter is to provide you with an overview of Biomet’s current evaluation of the Kaplan-Meier survivorship and revision data of these devices.

Biomet's M2a™ MoM total hip arthroplasty (THA) system was introduced in 2000. Biomet initially obtained clearance to market its M2a-Taper™ system in the United States based on clinical study data from a prospective, randomized controlled investigational clinical study and pre-clinical data which met the requirements of the United States Food and Drug Administration (FDA). Biomet later received additional FDA clearances, as well as EC design examination certificates for various MoM systems from the British Standards Institute. To obtain these design examination certificates, Biomet submitted clinical evaluation reports describing the clinical data pertinent to these devices. In sum, Biomet has marketed the following MoM THA systems:

  • Biomet M2a–Magnum™;
  • Biomet M2a-38™;
  • Biomet M2a–Taper™;
  • Biomet M2a–Ringloc™;
  • Biomet M2a-28mm™;
  • Biomet Stanmore™; and
  • Biomet Exceed ABT™.

As part of its post-market surveillance, Biomet has collected data on approximately 24,000 hips treated with Biomet MoM THA systems, including data from the Australian, England and Wales, Swedish, Finnish and New Zealand National Joint Registries (NJR); pre- and post-market clinical studies; licensed clinical databases and published clinical results. Table 1 reflects the subset of data that Biomet was able to analyze for either Kaplan-Meier survivorship or revision rate per 100 observed component years (OCY) for each of the above-identified Biomet MoM THA systems. Where sufficient information is available after the data is pooled for meta-analysis, Biomet is providing the following results: Kaplan-Meier survivorship and revision rate per 100 OCY; a benchmark comparison to overall MoM and overall THA Kaplan-Meier survivorship reported by the Australian NJR1; a benchmark comparison to overall MoM Kaplan-Meier survivorship reported by the England and Wales NJR; a benchmark comparison to revision rate per 100 OCY reported by the Australian1 and England and Wales NJRs; and an analysis of gender impact on risk of revision. Data regarding clinical experiences with Biomet MoM THA systems, other than Kaplan-Meier survivorship and revision rate, are not described in this letter.


Table 1

Type of Data Source

M2a–Magnum

M2a-38

M2a–Taper

M2a–Ringloc

M2a-28mm

Stanmore

Exceed ABT

National Joint Registries

3680

2272

0

0

195

0

17**

Clinical Studies

830

527

307

0

0

102*

0

Databases

2249

1514

558

0

 

 

 

Publications

0

0

0

0

0

102*

0

Total

6759

4313

865

0

195

102

17

*Based on the same data source
**insufficient data for analysis

M2a-Magnum:

Biomet has evaluated clinical data on 6759 M2a-Magnum cases contributing to survival analysis. Based on this data, the Kaplan-Meier survivorship is 95.07% at 5 years; and the revision rate per 100 OCY is 0.72.

The Kaplan-Meier survivorship in the Australian NJR for all MoM hips is 94.0% at 5 years, and for all THA is 96.6% at 5 years.  There is not a statistically significant difference between the Kaplan-Meier survivorship for M2a-Magnum and all MoM or all THA in the Australian NJR.

The Kaplan-Meier survivorship in the England and Wales NJR for all MoM hips is 92.7% at 5 years.  There is not a statistically significant difference between the Kaplan-Meier survivorship for M2a-Magnum and all MoM in the England and Wales NJR.

The revision rate per 100 OCY in the Australian NJR for all MoM hips is 1.23, and for all THA is 0.74. There is not a statistically significant difference between the revision rates per 100 OCY for M2a-Magnum and all THA in the Australian NJR. The revision rate per 100 OCY for M2a-Magnum is statistically significantly lower than that for all MoM in the Australian NJR.

The revision rate per 100 OCY in the England and Wales NJR for all MoM hips is 1.73, and for all THA is 0.74. There is not a statistically significant difference between the revision rates per 100 OCY for M2a-Magnum and all THA in the England and Wales NJR. The revision rate per 100 OCY for M2a-Magnum is statistically significantly lower than that for all MoM in the England and Wales NJR.

The impact of gender on risk of revision is not statistically significant.

 

M2a-Magnum

Australian NJR – All MoM

Australian NJR – All THA

England and Wales NJR – all MoM

England and Wales NJR – all THA

Kaplan-Meier survivorship – 5yr

95.1 (89.0, 100)

94.0 (93.5,94.4)

96.6 (96.5,96.7)

92.7 (92.1,93.4)

-

Revision rate per 100 OCY

0.72(0.60,0.85)

1.23 (1.15,1.31)*

0.74 (0.72,0.76)

1.73 (1.64,1.83)*

0.74 (0.72,0.76)

* Biomet results are statistically significantly lower than benchmarks per confidence intervals.

M2a-38:
Biomet has evaluated clinical data on 4313 M2a-38 cases contributing to survival analysis. Based on this data, the Kaplan-Meier survivorship is 90.93% at 7 years; and the revision rate per 100 OCY is 0.96

The Kaplan-Meier survivorship in the Australian NJR for all MoM hips is 92.7% at 7 years, and for all THA is 95.6% at 7 years.  There is not a statistically significant difference between the Kaplan-Meier survivorship for M2a-38 and all MoM or all THA in Australian NJR. 

The Kaplan-Meier survivorship in the England and Wales NJR for all MoM hips is 86.4% at 7 years.  There is not a statistically significant difference between the Kaplan-Meier survivorship for M2a-38 and all MoM in the England and Wales NJR. 

The revision rate per 100 OCY in the Australian NJR for all MoM hips is 1.23, and for all THA is 0.74. The revision rate per 100 OCY for M2a-38 is statistically significantly lower than that for all MoM in the Australian NJR. The revision rate per 100 OCY for M2a-38 is statistically significantly higher than that for all THA in the Australian NJR.

The revision rate per 100 OCY in the England and Wales NJR for all MoM hips is 1.73, and for all THA is 0.74. The revision rate per 100 OCY for M2a-38 is statistically significantly lower than that for all MoM in the England and Wales NJR. The revision rate per 100 OCY for M2a-38 is statistically significantly higher than that for all THA in the England and Wales NJR.

 

M2a-38

Australian NJR – All MoM

Australian NJR – All THA

England and Wales NJR – all MoM

England and Wales NJR – all THA

Kaplan-Meier survivorship – 7 yr

90.9 (84.9,96.9)

92.7 (92.1,93.2)

95.6 (95.5,95.8)

86.4 (83.0,89.1)

-

Revision rate per 100 OCY

0.96 (0.82,1.11)

1.23 (1.15,1.31)*

0.74 (0.72,0.76)**

1.73 (1.64,1.83)*

0.74 (0.72,0.76)**

* Biomet results are statistically significantly lower than benchmarks per confidence intervals.
** Biomet results are statistically significantly higher than benchmarks per confidence intervals.

Biomet learned of a report from a single center in the United States of a statistically significantly higher risk of revision in female patients treated with M2a-38 than male patients. When data from that center is pooled with all data available to Biomet for analysis, there is a statistically significantly higher risk of revision in female patients treated with M2a-38 than male patients (female vs. male hazard ratio =1.58 (p<0.05). A statistically significantly higher risk of revision in female patients is not observed, however, when the data from the single U.S. center is excluded from the analysis (hazard ratio = 1.26 p>0.05).

Gender Impact on Risk of Revision (Female vs. Male)

Hazard Ratio

p-value

All Data Sources

1.58

0.03*

All Other Data Sources excluding the single center in US

1.26

0.33

Single center in US only

3.20

0.008*

*The gender impact is statistically significant.

The following table shows a gender analysis of Biomet results. The Kaplan-Meier survivorship for M2a-38 all female cases is statistically/marginally statistically significantly lower than all THA and all MoM in the Australian NJR.  The revision rate per 100 OCY for M2a-38 all female cases is statistically significantly higher than that for all THA in both the Australian NJR and the England and Wales NJR. When the data from the single U.S. center is excluded, there is not a statistically significant difference in Kaplan-Meier survivorship between M2a-38 female cases and any benchmarks, except all THA in the Australian NJR. The Kaplan-Meier survivorship for M2a-38 all male cases is statistically/marginally statistically significantly higher than all MoM in both the Australian NJR and the England and Wales NJR.  The revision rate per 100 OCY for M2a-38 all male cases is statistically significantly lower than all MoM in both the Australian NJR and the England and Wales NJR. 

 

M2a-38
All Male

M2a-38
All Female
Including the single US center

M2a-38
Female Excluding the single US center

Australian NJR – All MoM

Australian NJR – All THA

England and Wales NJR – all MoM

England and Wales NJR – all THA

Kaplan-Meier survivorship – 7 yr

95.1
(93.2, 96.5)

89.5
(86.1, 92.1)

92.2 
(89.0, 94.6)

92.7 (92.1,93.2)*

95.6 (95.5,95.8)*

86.4 (83.0,89.1)

-

Revision rate per 100 OCY

0.67
(0.49,0.89)

1.15 (0.91,1.42)

0.91
(0.68,1.18)

1.23 (1.15,1.31)

0.74 (0.72,0.76)**

1.73 (1.64,1.83)

0.74 (0.72,0.76)**

*Biomet results in females including the single US center is statistically/marginally statistically significantly lower than benchmarks per confidence intervals.
**Biomet results in females including the single US center is statistically significantly higher than benchmarks per confidence intervals.

M2a-Taper:
Biomet has evaluated clinical data on 865 M2a-Taper cases contributing to survival analysis. Based on this data, the Kaplan-Meier survivorship is 97.5% at 7 years; and the revision rate per 100 OCY is 0.39.

The Kaplan-Meier survivorship in the Australian NJR for all MoM hips is 92.7% at 7 years, and for all THA is 95.6% at 7 years.  The Kaplan-Meier survivorship for M2a-Taper is statistically significantly higher than that for all MoM and all THA in the Australian NJR. 

The Kaplan-Meier survivorship in the England and Wales NJR for all MoM hips is 86.4% at 7 years.  The Kaplan-Meier survivorship for M2a-Taper is statistically significantly higher than that for all MoM in the England and Wales NJR.

The revision rate per 100 OCY in the Australian NJR for all MoM hips is 1.23, and for all THA is 0.74. The revision rate per 100 OCY for M2a-Taper is statistically significantly lower than that for all MoM and all THA in Australian NJR.

The revision rate per 100 OCY in the England and Wales NJR for all MoM hips is 1.73, and for all THA is 0.74. The revision rate per 100 OCY for M2a-Taper is statistically significantly lower than that for all MoM and all THA in the England and Wales NJR.

The impact of gender on risk of revision is not statistically significant.


 

M2a-Taper

Australian NJR – All MoM

Australian NJR – All THA

England and Wales NJR – all MoM

England and Wales NJR – all THA

Kaplan-Meier survivorship – 7 yr

97.5 (96.8,98.2)

92.7 (92.1,93.2)**

95.6 (95.5,95.8)**

86.4 (83.0,89.1)**

-

Revision rate per 100 OCY

0.39 (0.23,0.60)

1.23 (1.15,1.31)*

0.74 (0.72,0.76)*

1.73 (1.64,1.83)*

0.74 (0.72,0.76)*

* Biomet results are statistically significantly lower than benchmarks per confidence intervals.
** Biomet results are statistically significantly higher than benchmarks per confidence intervals.

M2a-Ringloc:

Biomet has collected clinical data on 62 hips that received M2a-Ringloc. There is no survival time information to determine Kaplan-Meier survivorship or revision rate per 100 OCY or perform statistical analysis of gender impact on risk of revision.

M2a-28mm:
Biomet has evaluated clinical data on 195 M2a-28mm cases. There are a limited number of cases available for analysis. Nevertheless, based on this data, the Kaplan-Meier survivorship is 95.6% at 7 years; and the revision rate per 100 OCY is 0.56

The Kaplan-Meier survivorship in the Australian NJR for all MoM hips is 92.7% at 7 years, and for all THA is 95.6% at 7 years.  There is not a statistically significant difference between the Kaplan-Meier survivorship for M2a-28mm and all MoM or all THA in the Australian NJR. 

The Kaplan-Meier survivorship in the England and Wales NJR for all MoM hips is 86.4% at 7 years. There is not a statistically significant difference between the Kaplan-Meier survivorship for M2a-28mm and all MoM in the England and Wales NJR. 

The revision rate per 100 OCY in the Australian NJR for all MoM hips is 1.23, and for all THA is 0.74. There is not a statistically significant difference between the revision rates per 100 OCY for M2a-28mm and all MoM or all THA in Australian NJR.

The revision rate per 100 OCY in the England and Wales NJR for all MoM hips is 1.73, and for all THA is 0.74. There is not a statistically significant difference between the revision rates per 100 OCY for M2a-28mm and all THA in the England and Wales NJR. The revision rate per 100 OCY for M2a-28mm is statistically significantly lower than that for all MoM in the England and Wales NJR.

There is insufficient data to perform the analysis of gender impact on risk of revision.


 

M2a-28mm

Australian NJR – All MoM

Australian NJR – All THA

England and Wales NJR – all MoM

England and Wales NJR – all THA

Kaplan-Meier survivorship – 7 yr

95.6 (86.6, 98.6)*

92.7 (92.1,93.2)

95.6 (95.5,95.8)

86.4 (83.0,89.1)

-

Revision rate per 100 OCY

0.56 (0.18,1.30)

1.23 (1.15,1.31)

0.74 (0.72,0.76)

1.73 (1.64,1.83)

0.74 (0.72,0.76)

*Based on 88 cases from Australian NJR.

Stanmore MoM:

Biomet has evaluated clinical data on 102 Stanmore cases. Based on this data, the Kaplan-Meier survivorship is 95.5% at 10 years. There is insufficient data to calculate revisions per 100 OCY and gender impact on risk of revision. Due to lack of 10 year Kaplan-Meier survivorship information from NJRs, Kaplan-Meier survivorship at 10 years of Stanmore is compared to that at 7 years of NJRs.

The Kaplan-Meier survivorship in the Australian NJR for all MoM hips is 92.7% at 7 years, and for all THA is 95.6% at 7 years.  There is not a statistically significant difference between the Kaplan-Meier survivorship for Stanmore and all MoM or all THA in the Australian NJR. 

The Kaplan-Meier survivorship in the England and Wales NJR for all MoM hips is 86.4% at 7 years. The Kaplan-Meier survivorship for Stanmore at 10 years is statistically significantly higher than that for all MoM at 7 years in the England and Wales NJR.

 

Stanmore

Australian NJR – All MoM

Australian NJR – All THA

England and Wales NJR – all MoM

England and Wales NJR – all THA

Kaplan-Meier survivorship – 7 yr

95.5 (91.2, 99.8)*

92.7 (92.1,93.2)

95.6 (95.5,95.8)

86.4 (83.0,89.1)

-

*10 year Kaplan-Meier survivorship

Exceed ABT MoM:

Biomet has evaluated clinical data on 17 Exceed ABT cases. There is insufficient data to perform statistical analysis of gender impact on risk of revision or comparison to registry data.

Regulatory agencies have issued recommendations to surgeons for follow-up of patients with MoM hip implants. In April 2010 and February 2012, the Medicines and Healthcare Products Regulatory Agency (MHRA) of the United Kingdom issued medical device alerts regarding MoM hip implants, which were posted at: http://www.mhra.gov.uk/Publications/Safetywarnings/MedicalDeviceAlerts/CON079157 and http://www.mhra.gov.uk/home/groups/dts-bs/documents/medicaldevicealert/con143787.pdf.
In February 2011, the U.S. Food and Drug Administration (FDA) Center for Devices and Radiological Health posted an informational website for patients and orthopaedic surgeons on MoM hip implants, which is available at: http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/ImplantsandProsthetics/
MetalonMetalHipImplants/ucm241771.htm
.

In its April 2010 alert, the MHRA advised that surgeons should consider specific monitoring for certain patient groups, including cohorts of patients where there is a concern about higher than expected failure rates. In its February 2012 alert, the MHRA updated its advice with specific recommendations for patients treated with MoM total hip replacements with a femoral head diameter equal to or greater than 36mm. The FDA on its informational website recommends that follow-up should occur periodically for asymptomatic patients and provides more detailed guidance on follow-up and evaluation for patients with the presence of local symptoms such as pain or decrease in joint function that appear more than three months after MoM hip implant surgery. The FDA further advises that certain patients, including female patients, are at risk for increased device wear and/or adverse reactions to metal debris and should be monitored closely. Biomet encourages careful follow-up for all MoM patients, including close monitoring for women, particularly those women with a Biomet M2a-38 Metal-on-Metal Total Hip System.

Please consult the local Regulatory agency in your country of residence, such as the FDA, MHRA, Agence Française de Sécurité Sanitaire des Produits de Santé (French Agency for the Safety of Health Products) or Health Canada, for any additional information or recommendations on MoM hip implants. Biomet will continue to monitor the data regarding its MoM hip implants and take reasonable, evidence-based actions warranted by the data.

Robert E. Durgin
Senior Vice President, Quality/Regulatory/Clinical Affairs
Biomet, Inc.

 

1 Based on Primary Diagnosis of OA.


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