Total ankle replacement shows improvements on validated measures

DENVER — The first U.S. study reporting clinical and radiographic outcomes in patients with an uncemented, mobile-bearing total ankle replacement indicate good results with validated outcome measures.

Matthew DeOrio, MD, and colleagues prospectively studied 88 patients (91 ankles) implanted with the Scandinavian Total Ankle Replacement (STAR) Ankle Joint prosthesis (Link Orthopaedics) prosthesis by a single surgeon. The investigators evaluated the patients using pre- and 1-year-postoperative clinical outcome measures and assessed their radiographs at preop, 1-year-postop and most recent follow-up. The patients were an average age of 62 years and had a mean follow-up of 4.6 years.

DeOrio presented the results of the investigation at the American Orthopaedic Foot and Ankle Society (AOFAS) 24th Annual Summer Meeting, here.

The investigators found that the AOFAS ankle-hindfoot scores increased from 32.4 to 87.3 and the Visual Analog Scale (VAS) pain score improved from 74.5 to 10.96. They also discovered statistically significant improvements in both the physical and mental health components of the SF-36.

Thirteen patients (14%) underwent subsequent major surgical interventions. Two patients had malalignment and one had a talus fracture. Seven patients had interventions involving the bearing which included bearing component revision for impingement (three), bearing fracture (three) and an infection that required a component exchange.

Two ankle prostheses were removed. One was removed for a pseudomonas infection and was successfully converted to an ankle arthrodesis. The other was revised to an alternate ankle arthroplasty, subsided and was converted to a tibiotalocalcaneal fusion. One patient underwent reoperation for a fracture located though a pin hole of the distal tibia.

"[This] is the first study to demonstrate improvement in quality of life secondary to total ankle replacement using validated outcome scores including the VAS pain scale and the SF-36," DeOrio said. "We showed that there is a functional improvement by the AOFAS score which has been shown in previous studies. Patients will continue to improve after the first year. Adjacent joint arthritis may still progress and if you have to do a revision, there is a good probability of success overall having good to excellent results."

For more information:
DeOrio M, Nunley JA, Caputo A. Midterm clinical and radiographic follow-up of STAR prostheses implanted by a single surgeon. Presented at the American Orthopaedic Foot and Ankle Society 24th Annual Summer Meeting. June 26-28, 2008. Denver.