287. LONG-TERM RESULTS WITH THE SALTO™ TOTAL ANKLE PROSTHESIS

Abstract

Purpose of the study: The results of the first total ankle arthroplasties (TAA) using the Salto™ prosthesis were published in 2004 with mean 35 months follow-up. The purpose of this work was to update the results of the initial multicentric series.

Material and methods: From 1997 to 2000, 98 TAA were performed with a Salto™ prosthesis in three centres: 62 women, 36 men, mean age 56 years, age range 26–81 years, mean BMI 24.3 kg/m². The patients had osteoarthritis (n=65; posttraumatic 43, post-instability 8, primary 14), rheumatoid arthritis (n=29), and sequel of septic arthritis (n=4). At last follow-up, nine patients had died (none had had revision surgery of the ankle) and one patient had been amputated for an unrelated reason. The remaining patients (88 TAA) were reviewed in an outpatient clinic with a mean 102 months follow-up (range 65–134). None of the patients were lost to follow-up.

Results: Seven prostheses were replaced by an arthrodesis (six osteoarthritis and one rheumatoid arthritis): three for defects at 44, 72 and 101 months after implantation, two for unexplained pain after 32 and 57 months, one for tibial loosening after 62 months and one for infection after six months. One tibial piece was changed for loosening and fracture of the polyethylene insert after 100 months (revision with a longer anchor piece). Two 3 mm polyethylene inserts were changed alone for fracture after 72 and 122 months. Five TAA were reoperated for stiffness: removal of bone fragments±synovectomy. Four TAA were grafted for secondary defects (two tibia and two talus). One lateral maleolar piece was removed for loosening after 88 months. There were two infections treated by synovectomy, wash-out and antibiotic therapy. The survival rates were 92% for failure=removal of the prosthesis; 91% for removal or replacement of one component; 89% for removal or replacement of one piece, including the polyethylene insert. The survival rate (prosthesis removal) was better for rheumatoid disease (97%). The AOFAS score at last follow-up was 81.5±12 (80.5±10.3 for osteoarthritis and 76.4±14.8 for rheumatoid disease).

Conclusion: These results underscore: the importance of rigorous technique and careful patient selection (five revisions for defective technique); the higher risk of infection (three cases); the importance of the thickness of the poly-ethylene insert (three fractures on 3mm inserts). Seven patients underwent revision to graft defects, four successfully and three failures (secondary arthrodesis).