• Orthopaedics Clinical Trials
• Orthopaedic Procedures
• Foot & Ankle Conditions

• Orthopaedics Clinical Trials
• Orthopaedic Procedures
• Foot & Ankle Conditions
• Orthopaedics

A study of 4 implants used for total ankle arthroscopy (TAA) found that the Agility and Mobility implants required higher rates of metal component revisions when compared with the Hintegra and STAR implants. In addition, the Mobility implant demonstrated less improvement in the total Ankle Osteoarthritis Scale (AOS) score and the mean AOS pain difference. Tina Lefrancois, MD, Dalhousie University, Nova Scotia, Canada, presented the study results.

End-stage ankle arthritis is frequently treated by TAA; with modern prostheses, clinical outcomes and patient-reported satisfaction are good. The purpose of this study was to determine any differences in clinical outcomes based on the 4 TAA implants (STAR, Hintegra, Agility, and Mobility).

In this multicenter study, prospectively collected data from the Canadian Orthopaedic Foot and Ankle Society ankle reconstruction database were analyzed to identify patients who underwent TAA from November 2001 to August 2010. Patients were excluded if they were < 40 years old or had nerve or muscle disease, severe osteoporosis, severe mental illness, a severe deformity, or an active infection within the previous 12 months. The baseline characteristics were similar among all 4 groups. Patients had a mean age of 63 and a mean body mass index of 28. About 10% of patients had diabetes, and about 10% were smokers, although only 5% in the Mobility arm were smokers. Approximately 22% of patients had inflammatory arthritis (28% in the Agility arm), and nearly half of the patients were men.

The primary end point of the study was SF-36 scores and the AOS scores. The secondary end point was the need for reoperation. The mean follow-up time varied according to the implant used: 6.3 years for STAR, 3.5 for Hintegra, 6.1 for Agility, and 4.2 for Mobility.

Among patients who received the STAR, Hintegra, or Agility implant, the mean difference in total AOS score from baseline was similar; patients who received the Mobility implant demonstrated a lower mean difference in AOS score. In addition, the difference in AOS pain scores from baseline was smaller in the Mobility group (21.2) when compared with the STAR, Hintegra, and Agility groups (29.1, 29, and 29.8, respectively).

About 25% of patients who received the Hintegra, Agility, or Mobility implant and 36% of patients who received the STAR implant required reoperation. Reoperation in the STAR group was a result of isolated polyethylene exchange due to polyethylene failure, which was not observed in any other implant group. Revision of metal components due to aseptic failure was 15% and 20% in the Mobility and Agility implant groups, compared with 7% and 8% in the Hintegra and STAR implant groups, respectively. The amputation rate after TAA was 0% for the Hintegra group, 1% for the STAR and Mobility groups, and 3% for the Agility group. After adjusting for the requirement of metal component revision and polyethylene exchange, use of the Mobility implant resulted in poorer outcomes as compared with the STAR, Hintegra, and Agility implants (P = .01 for all).

According to Prof Lefrancois, the study results indicate that there are subtle differences among the TAA implants, and knowledge of these differences is important when determining which implant is the best option for a given patient.

• © 2014 MD Conference Express®