Issue: August 2007
August 01, 2007
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Low morbidity, few dislocations make hip resurfacing an option for young patients

Careful selection can help patients regain function and have a satisfactory quality of life.

Issue: August 2007
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AOA

Better surgical techniques and patient selection will enable total joint surgeons to achieve more reproducible results in the young arthritic patient with hip resurfacing implants, according to Paul E. Beaulé, MD, FRCSC.

By mastering the technique and selecting the right patients for this procedure, they can mitigate the 15% to 30% failure rates seen with some earlier designs of hip resurfacing prostheses, he said.

But, Beaulé, a proponent of resurfacing arthroplasty to treat hip arthritis in appropriate patients, also expects the type and design of fixation to be critical to long-term success with today’s resurfacing components. Deep cement penetration may have contributed to past failures, he said.

“How all these factors interact will affect the clinical outcomes we see,” Beaulé said in a presentation at the 120th Annual Meeting of the American Orthopaedic Association.

Conserve the joint

Modern hip resurfacing dovetails nicely with such clinical goals as joint preservation and keeping open future surgical options. An additional benefit is fewer dislocations. The downside of hip resurfacing is known or suspected problems, like femoral neck fracture and metal ion release, which will require further study, according to Beaulé.

“I think these are exciting times in hip arthroplasty. We are minimizing the time to recovery with improved surgical techniques, better pain management, lower risk of dislocation, and an earlier return to work so patients can have a greater capacity to live their lives to the fullest. Joint preservation should be the first step, more durable implants the second step,” he said.

Beaulé also urged surgeons to keep abreast of the procedure’s latest clinical results since hip resurfacing is lacking long-term follow-up.

Resurfacing arthroplasty is mainly indicated for young patients with hip arthritis. “It is limited to a select few from the patient’s and surgeon’s perspective,” Beaulé said.

“The current limitations of hips resurfacing are aseptic loosening of the femoral component… Metal ion release remains high. And …although uncommon, it is still uncertain if we can fully eliminate neck fractures.”

Compared to total hip arthroplasty (THA), resurfacing arthroplasty is less than optimal for correcting significant leg length discrepancies, but may be superior for more precisely restoring overall hip biomechanics.

Hip resurfacing failures
Femoral neck fractures and head devascularization remain chief causes of hip resurfacing failures.

Image: Campbell PC

Selection factors

According to Beaulé, the following patient selection factors can favorably impact modern resurfacing outcomes:

  • no large femoral head cyst;
  • no osteopenia;
  • younger than 65 years old; and
  • no prior hip surgery.

“My current ideal indications for hip resurfacing are patients age less than 60 years, risk index less than or equal to 3,” he said.

The risk index — surface arthroplasty risk index (SARI) — is a tool for determining how various factors may interact for a reproducible outcome.

SARI gives two points each for a femoral head cyst >1 cm3 and patient weight <82 kg, and one point each for previous hip surgery and UCLA activity score >6, for a total possible score of 6. The higher the patient’s SARI, the greater his or her risk of implant failure.

Beaulé applied the index in a study he did of 400 patients following resurfacing arthroplasty. The overall series showed a survivorship of 94% at 4 years, which most would consider suboptimal compared to THA.

After grouping patients by SARI, survivorship increased to 97% in those with SARI equal to or less than 3. But it decreased to 89% when the index was equal to or greater than 3.

Surgical technique

However, the role that proper surgical technique plays in resurfacing outcomes cannot be over emphasized. “Performing hip resurfacing is different than performing a total hip,” Beaulé said. And there is no getting around the learning curve.

Femoral neck fractures — a dramatic failure for patient and surgeon — is a technique-related complication that must be surmounted.

“Neck fracture remains one of the greatest limitations of resurfacing because it is unique to hip resurfacing,” Beaulé said. He cited varying fracture rates from the Journal of Bone and Joint Surgery ranging from 0.8% (Amstutz, 600-patient series) to 1.5% (Shimmin, 3,497 hips; Australian hip arthroplasty register).

On the plus side, patients with successful procedures stand to truly benefit from the procedure through activity restoration and thus maintaining better health and mental status.

Some even return to a very high level of function. However, Beaulé noted, “we need to look at the long term effects of such a high activity level in these patients.”

Patient considered for hip resurfacing surgery
The surface arthroplasty risk index was 4 for this 37-year old woman, who was being considered for hip resurfacing surgery.

Ceramic-on-ceramic total hip replacement
She ultimately underwent successful ceramic-on-ceramic total hip replacement, because her large femoral cyst and small frame could put her at risk for early failure with resurfacing arthroplasty.

Image: Beaulé PE

For more information:
  • Paul E. Beaulé, MD, FRCSC, can be reached at Ottawa Hospital, 501 Smyth Road, Ottawa, Ont., Canada; 613-737-8899; E-mail: pbeaule@ottawahospital.on.ca. He received miscellaneous support from Getinge USA and is a consultant/employee of Wright Medical Technology, Brain Labs, and FDA.
References:
  • Amstutz HC, Campbell PA, Le Duff NJ. Fracture of the neck of the femur after surface arthroplasty of the hip. J Bone Joint Surg Am. 2004;86:1874-1877.
  • Beaulé PE. Hip resurfacing: Role in treatment of hip arthritis. Symposium 6: The young adult with hip arthrosis: There are finally options. Presented at the 120th Annual Meeting of the American Orthopaedic Association. June 13-16, 2007. Asheville, N.C.
  • Girard J. Lavigne M, Vendittoli PA, Roy AG. Biomechanical reconstruction of the hip: A randomised study comparing total hip resurfacing and total hip arthroplasty. J Bone Joint Surg Br. 2006;88:721-726.
  • Shimmin A, Back D. Femoral neck fracture following Birmingham hip resurfacing. J Bone Joint Surg Br. 2005;87B:463-464.