Table of Contents
Why Minimally Invasive Surgery?
With a minimally invasive 4-5 inch posterior approach, minimal blood loss, and multimodal pain management, outpatient surgery is possible. This is more convenient, pleasant, and less costly. Since 2012, we have perfected this outpatient approach for all joint replacement procedures, and over 80% of my operations are done this way. Local patients return directly home on the day of surgery, and out-of-state patients stay in a hotel for 1-2 nights before traveling home. Patients with certain major medical comorbidities, uncooperative insurance plans, or those without capable caregivers are still done at the hospital with a one-night overnight stay. I strongly recommend against staying at rehab facilities unless a patient cannot arrange any support at home.
Accurate X-ray Based Component Positioning
The most critical factor in consistently achieving excellent outcomes in resurfacing is accurate acetabular component positioning. Adverse (Metal) Wear Related Failures (AWRF) can now be completely avoided, even in higher-risk patients requiring smaller implant sizes, by proper acetabular component positioning. We published the world’s first component positioning guideline that is supported by data. We named it RAIL – Relative Acetabular Inclination Limit. We then developed intraoperative X-ray techniques that allow us to achieve RAIL in every case. We monitor all patients for excessive wear using blood ion levels. As a result, we have not created a single AWRF since 2009 (10 years, >4000 cases). Prior to 2007, the rate was 1% at 10 years.
Why Uncemented Implants?
All HRA use uncemented bone-in growth fixation on the socket side. Most brands including the BHR are cemented on the femoral side. We have demonstrated that uncemented fixation on the femoral side gives superior results to cement. Cement is a brittle acrylic material that heats up during implantation (polymerization reaction) burning the femoral head and increasing the chance of early femoral failure. It also is subject to fatigue failure over time resulting in implant loosening type failure.
With uncemented femoral components, we have had a 100% bone ingrowth rate. 0.4% fail due to neck fracture or head collapse, only 1/5000 has come loose since 2007. My femoral loosening rate with cement was 1% by 10 years when I used cement before 2007. We can demonstrate no difference in the early femoral failure rate between cemented and uncemented femoral implants. The difference in late loosening between cemented and uncemented femoral is 1% vs 0.05% at 10 years, this is statistically significant.
Is Resurfacing Safe in Women?
Yes. Durability is equal to men in the last 10 years. Early data from many centers indicated that women had a higher risk of failure due to femoral neck fracture, failure of acetabular ingrowth, and adverse metal wear-related failure (AWRF) than men did. I have data to show that I solved all of these problems at least 10 years ago. Ten-year implant survivorship in women is now 99%; it is now equal to that in men. Femoral neck fractures are rare (0.2%). A trispike acetabular component introduced in 2007 has eliminated the acetabular component failures in deformed dysplasia sockets (90% of dysplasia occurs in women). Understanding proper acetabular component positioning has allowed us to implant acetabular components to avoid AWRF (no new cases since 2009).
Solving the Problems of Revision Failed Resurfacings
Our published results are nearly as good as for primary surgery. Others have also published excellent results for revision hip resurfacing. Most reports on revision for the problem of adverse wear-related failure (AWRF), however, are poor. The worst report is from Oxford, with a 50% short-term failure rate. We have experienced a 100% success rate for AWRF by revising these failures with new large metal bearings placed correctly according to new implant positioning guidelines that we have developed.