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Consider femoral morphology, bone quality in selecting patients for hip resurfacing
Patients who seek hip resurfacing want to lead an active lifestyle without limitations, surgeon says.
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The indications for total hip resurfacing are narrow, and careful patient selection and surgical technique are crucial to obtaining good outcomes.
At Orthopedics Today Hawaii 2009, Section Chair Thomas P. Schmalzried, MD, discussed the indications for hip resurfacing and presented tips on performing the procedure.
“The indications have been refined,” Schmalzried said. “There is no need for any new comer to repeat the learning curve. The patients have higher activity and break the no-restriction policy, and are at actually higher survivorship than total hip in the at-risk patient.”
Indications
The results of the procedure are due to the quality of the starting material, he said. If the walls of the acetabular component are less than 4 mm thick, the amount of acetabular reaming is similar to that for a conventional total hip component, and the operation is conservative on the acetabular and femoral side.
“There are differences on the femoral side,” Schmalzried said. “The offset of the femur after resurfacing surgery is just like it was before. You cannot change the offset. You cannot improve the offset.”
He also noted that the procedure can lengthen limbs up to 1 cm.
He has narrower indications for resurfacing than total hip replacement (THR). “My indications are those patients who are at an increased risk for failure with a total hip, [have a] good proximal femur or a femoral deformity or device that would complicate or difficult putting a total hip in,” Schmalzried said.
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Image: Beadling L, Orthopedics Today |
Patient selection
He cited research by Harlan C. Amstutz, MD, which reported a higher risk of femoral-side failure after metal-on-metal surface replacement in women, patients with smaller component sizes, large femoral defects, relative varus positioning and older patients. Large men with osteoarthritis had the highest survivorship rates, because they had denser bone and larger areas of fixation, Schmalzried said.
He said surgeons should consider resurfacing because patients are living longer and harder.
“In the eyes of many of our patients, it is not longevity,” Schmalzried said. “It is lifestyle. They are unaccepting of disability. They seek early intervention and they do not want any restrictions. They are actually more concerned about having the big spike put in their femur than the resection of the head.”
THR limits
Some surgeons emphasize the limitations of THR, making resurfacing an even more attractive option for patients.
“To some degree, the medical community has created a poor image for total hips,” Schmalzried said.
Recent studies have also indicated that resurfacing maintains bone, and that patients have better outcomes with earlier intervention. Schmalzried attributed the good outcomes of resurfacing to the patients.
“The resurfacing patients are, on average, more active than total hip replacement patients,” he said. “There are at least three studies that have seen that.” He also highlighted differences between the attitudes of patients undergoing resurfacing and THR. “The patients seek resurfacing because they intend to have a vigorous lifestyle and not accept any limitations,” Schmalzried said.
Tips
Schmalzried obtains AP, frog lateral and Johnston lateral views to perform the procedure.
“You are really resurfacing around the neck,” Schmalzried said. “You are not really resurfacing the head, so you want to make sure that you understand what is going on at the head-neck junction and translate those landmarks on the radiograph into your operation. Do not get this confused with small incision surgery. When you are first starting to do this, make a reasonable skin incision.” In addition, surgeons should avoid high lateral open angles and increased anteversion.
He uses femoral suction to get a dry interface for the cement. “Retrieval studies have indicated that aberrations in cementing are a consistent finding in short-term failures,” Schmalzried said.
Surgeons can also convert the procedure to a total hip if there is a femoral-side failure.
“In terms of operative time and blood loss, it is very similar to the primary total hip,” he said.
For more information:
- Thomas P. Schmalzried, MD, medical director, Joint Replacement Institute, can be reached at 2200 W. Third St., Los Angeles, CA 90057, 213-484-7600; e-mail: schmalzried@earthlink.net He has a consulting and research relationship with DePuy, a Johnson & Johnson company, and Stryker Corp.
Reference:
- Schmalzried TP. Update on total hip resurfacing. Presented at Orthopedics Today Hawaii 2009. Jan. 11-14, 2009. Kohala Coast, Hawaii.