1. The Role of Hip Resurfacing
John R. Moreland, M.D.
Transforming Orthopaedics: Advanced Outcomes and Techniques
January 30-February 2,2008
Vail, Colorado

2. Déjà Vu
Residency and fellowship at UCLA with Dr. Harlan Amstutz 1973 to 1978
Fellowship with Mr. Michael Freeman in London
Revised many of my own and other surgeons’ surface failures
Revised only one MOM surface

3. Is There a Role for Surfaces?
When a stem can not be placed.
How large a role otherwise?
Probably surface replacement should currently have a small roll since for most patients the apparent disadvantages outweigh the advantages.
Time will define the proper role for surface replacement since the experiment to determine its place has already begun.

4. Difficulty of Surgery
There is general agreement that surface replacement is harder than using stems since the acetabular preparation must be done with the femoral head in place.

5. Minimally Invasive Issues
Stem placement
Involves less soft tissue damage
Surface placement
Femoral head is in the way and young male patients with big muscles often request surface
Bone conserving
Femoral side: more bone conserving than cemented stems, less so for cementless
Acetabular side: not more bone conserving
Easier to remove for infection or malposition compared to an osseointegrated stem.

6. Revision for Acetabular Fixation
Stems
Very low, multiple designs
Surface
Low in early reports
Less exposure available to place acetabular component
No adjuvant fixation
Must use cobalt-chrome components
No apical hole
Increased frictional torque

7. Revision for Femoral Fixation
Stems
Very low, multiple designs
Cementless designs easy to revise if loose.
Surface
Higher rate than stems in early reports
? Osteonecrosis of femoral head
Small surface area for fixation
Technical insertion issues

8. Femoral Issues Stems Surfaces Fractures Thigh pain Stress shielding
Operative
Late fractures
Thigh pain
Stress shielding
Surfaces
Neck fractures
Neck narrowing
Stress shielding/osteolysis
? late neck fractures

9. Dislocation Stems Surfaces Rates vary MOM with big heads can be used
Promise of lower rates not realized
Increased soft tissue damage necessary to get exposure is the probable reason

10. Range of Motion Stems Surfaces
Big head diameters relative to neck size give greater ROM before neck impingement
Postoperative ROM actually more dependent on other factors
Surfaces
Poor head to neck diameter ratio
More susceptible to getting heterotopic bone formation and being impaired by it

11. Nerve Damage
Will probably be higher with surfaces because of the extra retraction necessary to obtain exposure
Some reports have already documented this

12. Metal on Metal Problems
Metal ion issues
Cancer
Metabolic changes
Fetus exposure
Renal failure
Metal hypersensitivity
Clicking and squeaking

13. Other Surface Disadvantages
The learning curve for the surgeon, the operating room personnel and the patients
Requires instrument purchases and storage
Requires familiarity with two ways of doing THR
Requires a more expensive prosthesis with insurance coverage issues and possible medical liability issues for a new operation without established indications.

14. Surface Replacement Advantages
For patients with deformed proximal femurs
Easier to remove than osseointegrated stems for infection or malposition
Easy to market and build your practice
Intuitively attractive
Often confused with MIS and big heads
Do surfaces allow better function?
Might be true for high level activities
Few of my stem patients ever return to distance running
? Stress fractures of femoral neck

15. Is There a Role for Surfaces?
Yes: when a stem can not be placed
How large a role otherwise?
Probably a small role since for most patients the disadvantages outweigh the advantages
Long term follow-up will tell us
Need matched series since the differences are apparently not large
Is the function with surfaces better than stems for high level activities?

16. Thank You