Healio
Healio
July 22, 2009
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Better function seen in total ankle replacement vs. ankle fusion at 2 years

Prospective study of a TAR device also finds more complications following the procedure.

VANCOUVER, British Columbia — In an investigation called "revolutionary" by American Orthopaedic Foot and Ankle Society (AOFAS) Immediate Past President Robert B. Anderson, MD, researchers found better function with total ankle replacement compared to ankle fusion in a 2-year prospective controlled trial using an uncemented, mobile-bearing total ankle device.

The society’s incoming president Charles L. Saltzman, MD, presented the study, which earned the Roger A. Mann Award for best clinical research.

“By 24 months in this trial, the Scandinavian Total Ankle Replacement (STAR, Small Bones Innovations Inc.) had better function and equivalent pain relief to fusion,” Saltzman said at the 25th Annual Summer Meeting of the AOFAS, here.

“The study criteria for overall success were achieved more frequently after STAR ankle replacement,” he said, noting that the STAR was also associated with a higher rate of complications and secondary procedures. “Secondary procedures decreased by 50% during the study period.”

IDE study

The multicenter research was part of an FDA investigational device exemption (IDE) study to determine the safety and efficacy of the STAR prosthesis for patients with end-stage ankle arthritis. The pivotal study had a non-inferiority design and used fusion as a comparative procedure.

Overall success was determined by the FDA as meeting all of the following criteria:

  • no major complications;
  • no device failures, revisions or removals;
  • radiographic success; and
  • a 40-point improvement in the Buechel-Pappas ankle score.

The pivotal arm of the study included 158 total ankle replacement (TAR) patients and 66 fusion patients. In addition, a continued-access arm of the study included 448 TAR patients.

The investigators collected 2-year results on 95% of TAR patients in the pivotal study arm, 78.5% of fusion patients and 66% of continued-access TAR patients.

Success rate

The investigators found a 58.5% overall efficacy success rate for the pivotal TAR group, compared to 14.9% for the fusion group. In addition, they discovered a 76.1% success rate for the continued-access TAR patients.

Charles Saltzman
Charles L. Saltzman

Patients in the pivotal TAR group had a higher rate of major complications requiring surgery (8.9% vs. 1.5%) and secondary surgical interventions (16.5% vs. 10.6%) compared to the fusion group. However, the investigators found that the rate for surgical intervention in the continuous access group was 8.5%.

A further analysis examining the surgical intervention rates for revision or removal revealed a 7.6% rate for the pivotal TAR group and a 3.7% rate for the continued-access group.

In addition, the investigators discovered that the total ankle replacement met the criteria for non-inferiority. They found that 45% of patients in the pivotal TAR group reached all of the criteria for overall success compared to 13.7% of patients in the fusion group. They also noted that 62.1% of patients in the continued-access group met the criteria.

For more information:

  • Charles L. Saltzman, MD, can be reached at the Department of Orthopedics, University of Utah, 590 Wakara Way, Salt Lake City. UT 84108; 801-587-5404. He was a paid consultant for Link Orthopaedics in 2007.

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