Ninety eight percent of the time a hip or knee is implanted in the UK, Wales or Australia, a public record is generated—of the implant, the cement, the failures, the types of patients, the hospitals and the surgeons.
The United States is not so far behind with a similar system of public disclosures otherwise known as a “registry.”
So, ready or not, here’s a new level of data transparency.
A couple weeks ago, the UK’s 7th Annual National Joint Registry landed like a brick on my desk and was quickly followed the next week by Australia’s registry. Actually, flipping through the data tables revealed some very interesting market share and outcome data. Even beyond that, each registry tackled major clinical issues using their own data to provide clinicians with guidance.
For those OTW readers who don’t have a copy of the registries, here is a sampling of the data they offer.
In the following table we provide some basic data about each registry (this is not meant to be a comprehensive list):
| Registry Name | Year Data Initially Collected | Number of Procedures | Types of Procedures | Number of Participating Hospitals |
| UK/Wales NJR | 2002 | 736, 632 (approx: 163, 940 in 2009/2010) | Hip and Knee procedures | 393 |
| Since 2005, the number of primary hip replacements have risen 16%, knees by 23% | ||||
| Australian Hip and Knee Arthroplasty Registry | 1999 | 547, 607 (approx: 74, 000 in 2009) | Hip, Knee, Shoulder, Wrist, Elbow and Spine procedures | 299 |
| Since the registry started, the number of hip replacements have risen 26.3%. Knees are up 42.6%. | ||||
For those among our readers who are not familiar with registries, we refer you to one of the oldest and most reliable ones in the United States—Dr. Donald Shelbourne’s home grown knee registry—which we profiled in Elizabeth Hofheinz’s December 14, 2010, OTW article “Just the Facts, Doc.” In Dr. Shelbourne’s case, using registry data has profoundly changed and improved his practice.
On the horizon is American Academy of Orthopaedic Surgeon’s (AAOS) registry which was incorporated as the American Joint Replacement Registry (AJRR) in 2009. AAOS’s goal is to set up a comprehensive, national, independent and not-for-profit large joint registry.
Here are the highlights from the two national large joint registries that issued reports this year.
The UK/Wales National Joint Registry—Selected Tables
Condylar Knees
The top selling brand of total condylar knee implant is DePuy’s PFC Sigma knee which holds a dominating and steady share of the UK market. The one total condylar knee implant that seems to be consistently gaining market share is Smith & Nephew’s Genesis 2.
Unicondylar Knees
The top selling brand of unicondylar knee implant is Biomet’s Oxford partial knee. It absolutely dominates the market with between a 75% and 80% market share.
Patello-Femoral Knees
The top selling patello-femoral knee brand is still, but perhaps not for long, Stryker’s Avon system. Three other brands are rapidly gaining share specifically Wright Medical’s FPV knee system, Smith & Nephew’s Journey and, interestingly, Zimmer’s Gender PF.
Fixed Hinge Knees
Finally, in the fixed hinge knee category, Waldemar Link’s Endo rotating hinge knee has captured the top spot from Stryker’s MRH knee system. Indeed in the fixed hinge knee category, there appears to be Waldemar and then everyone else.
Hips
Among cemented stem brands, Stryker’s Exeter V40 has come to dominate the market, which is very impressive considering that the original Exeter design was brought to market nearly 40 years ago.
Naturally enough, Stryker’s contemporary hip cup brand, like the Exeter V40 stem, has come to dominate all hip replacement brands in the UK and actually gained more share in 2009.
DePuy’s Corail cementless hip stem has also come to dominate its market and JRI Orthopedics Furlong HAC system appears to have been the primary market share loser in this battle.
Two cementless hip cup brands have been consistently gaining market share; DePuy’s Pinnacle system and Stryker’s Trident system. Zimmer’s Trilogy hip has lost the most share, having dropped from market leadership in 2003 with a 25% to #3 in this segment with about a 10% share.
Source: ©National Joint Registry 2010
Revision Rates
In terms of revision rates, the cemented stems performed better than cementless stem. The best performing hip stem implant overall (whether cemented or cementless) was Zimmer’s MS-30 brand which had only a 0.9% rate of revision at three years and a 1.3% rate of revision at five years. Interestingly enough, in terms of market share; the MS-30 did not crack the top five implants. Overall, the rate of cemented hip stem implant revisions was 1.3% at three years and 2.0% at five years.
The worst rate of revisions was recorded for DePuy’s S-Rom at three years and for Zimmer’s CLS stem at five years.
Table 3.3 – Revision rates according to stem brands for primary hip replacement procedures, undertaken between April 1, 2003 and December 31, 2009, which were linked to a HES/PEDW episode.
In terms of knee implants, total knee revisions averaged only 2.0% at three years and 2.8% at five years. The implant with the lowest rate of revision was Stryker’s Triathlon knee at three years and Finsbury’s MRK knee at five years. The worst rate of revisions was recorded for Stryker’s Avon knee which had a 10.2% rate of revision.
Table 3.11 – Revision rates at three and five years according to the most frequently used brands for knee replacement procedures, undertaken between April 1, 2003 and December 31, 2009, which were linked to a HES/PEDW episode.
The Australian Registry—Selected Tables
The top selling brand in Australia was also the bestselling brand in the UK. For total knee replacements, Stryker’s Triathlon is #1 in both Australia and the UK. Biomet’s Oxford knee is the largest selling unicompartmental implant in the Australia as it also was in the UK. For total hip replacement, the Exeter V40 is, as it is in the UK, the leading market share brand. And finally the top selling acetabular component in Australia is Stryker’s Trident.
|
KNEES |
HIPS |
||||
| Rank | Implant Type | Unit Volumes | Rank | Implant Type | Unit Volumes |
| Femoral Prostheses for Total Knee Replacements | 33, 884 (231, 409 since registry inception) | Prostheses in Total Hip Replacements | 23, 465 (171, 104 since registry inception) | ||
| #1 | Triathlon | 4, 670 | #1 | Exeter V40 | 5, 236 |
| #2 | PFC Sigma | 3, 853 | #2 | Corail | 3, 584 |
| #3 | LCS | 3, 737 | #3 | Secur-Fit | 1, 273 |
| #4 | Nexgen CR Flex | 3, 370 | #4 | Accolade | 1, 108 |
| #5 | Genesis II | 3, 157 | #5 | CPT | 1, 023 |
| #6 | Nexgen LPS Flex | 2, 453 | #6 | Synergy | 1, 021 |
| #7 | Genesis II Oxinium | 1, 957 | #7 | Alloclassic | 914 |
| #8 | Vanguard | 1, 772 | #8 | Spectron EF | 721 |
| #9 | Scorpio NRG | 1, 267 | #9 | SL-Plus | 698 |
| #10 | Scorpio | 1, 172
|
#10 | CPCS | 689 |
| Tibial Protheses for UniCompartmental Cases | 3, 062 (31, 884 since registry inception) |
|
Acetabular Components in Total Hip Replacements | 23, 465 (171, 104 since registry inception) | |
| #1 | Oxford 3 | 788 | #1 | Trident | 6, 452 |
| #2 | ZUK | 465 | #2 | Pinnacle | 4, 000 |
| #3 | Unix | 349 | #3 | R3 | 2, 242 |
| #4 | Oxford | 224 | #4 | Trilogy | 1, 378 |
| #5 | Journey Deuce | 174 | #5 | Reflection | 1, 108 |
| #6 | Pres-Fixed | 168 | #6 | Allofit | 906 |
| #7 | Freedom/Active | 148 | #7 | Trab Metal Shell | 803 |
| #8 | Repicci | 132 | #8 | Delta Motion | 510 |
| #9 | GRU | 126 | #9 | Versafit | 441 |
| #10 | Allegretto Uni | 78 | #10 | ASR | 425 |
Implant Performance Data From Australia
Since Australia’s registry is older than that of the UK/Wales, performance data is available for up to nine years post implant. At nine years, hybrid fixation has the lowest cumulative percent revision at 4.5 %. By way of comparison, cemented and cementless implants had revision rates of 5.4%.
Cementless fixation had a higher risk of revision in the first month compared to cemented, however after three years the risk of revision for cementless fell below cemented.
The Australian data showed that there was an age-related difference in the risk of revision for cemented and cementless fixation. The risk of revision for cemented fixation decreased with age. Conversely, the risk of revision for cementless fixation increased with age. The risk for hybrid fixation did not vary with age. Cementless fixation had the highest risk of revision in the older age group (≥75 years) and this difference was most evident in the first two years (Figure HT15).
Hybrid fixation had a lower risk of revision compared to cemented fixation in the 55‐64 and 65‐74 year age groups. It is the same in the <55 and ≥75 year age groups. Compared to cementless fixation hybrid was the same in the <55 year age group but had a lower risk of revision in all other age groups, although in the 65‐74 year age group this is only in the first three months.
Next week, see how both Australia and the UK use registry data to find answers to difficult clinical questions and debatable topics.
