Sunday, August 7, 2011

Reviewing the market penetration of the hips over 5 years from the 2009 report of the National Joint of Registry of England and Wales (part 2 of x)

Today, I will review interesting information collected from the joint registry based on what appears to be  157,232 primary hip replacements and 2462  hip revisions.

1.  68% of the patients had mild disease prior to the implant but were not incapacitated.

2.  38%  were cemented hips and 33% were not.  there appears to be a decline in cemented hips.  Only a small portion 8% were resurfacing  vs total hip procedures.

3.  60% were female with 93% having osteoarthritis as the primary .indication for surgery.

4.  The average female was 68 years old and 65 years for a male.

5.  Surgical techniques:
  • large reduction in the use of cemented hips
  • ONLY 5% HAD MINIMALLY INVASIVE SURGERY!!! (Surprising to me that patients are still going through complex, long recovery surgery  vs using minimally invasive techniques.)
6.  The Stryker V40 cementless hip stem  had 60% of the market and was growing in this report.

7.  The Stryker Contemporary cemented cup was the market leader with 30% of the market and growing.

8.  The Depuy Corail had 45% of the market for cementless hip stems and was growing.

9.  The Pinnacle was the top selling cementless hip cups with 30% of the market and growing.

10.  There was a gradual increase in the femoral head size to reduce the incidence of revisions caused by recurrent dislocation.  36 inch and diameter and above were increasing.

11. Out of the 6000 patients that had specific data reported  on revisions in 2008, 54% were dues to aseptic loosening of the joint.

12.  Components removed during the revision surgery in 2008:
  • BOTH the femoral component and the cup were removed in 50% of the revision surgeries!!!
      • I found this surprising as well!
  • 25% of the time, the cup only was removed
  • 20% of the time the femoral stem only was removed.  (much more complicated operation to remove this stem.)
13.  Revision rates according to the type of material used over 5 years:

Type of material
Number of patients
Revision rate
Metal on poly
Ceramic on poly
Ceramic  on ceramic
Metal on metal (MoM)

I find this table really quite interesting.  First, what struck me  was the LOW  absolute number of patients with metal on metal implants to begin with. There doesn't appear to be a very
high rate of consumption of metal on metal in these two countries over a 5 year period. 

Second,  the highest rate of revision was with the ceramic on ceramic.  Kind of surprising.

Third, it struck me if the depuy hips were used , why were the revision rates so low?  Will be interesting to see the rates in 2010 and 2011.

I recall that most of my consults were not big users of MoM and also recall in the American Orthopedic Association's continuing Education Panel which Josh Jacobs MD  moderated he took a poll of the physicians who were using MoM in thier practice.  60% of the responding  physicians had under 20% of their patients implanted with MoM hip.  There is a post on that panel from late last year:

What percent of hip replacements are MOM bearings in your practice?

a. 60% said under 20%

b. 13% said 21-40%

c. 7% said 41-60%

d. 7% said 61-80%

e. 6% said over 80%

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