Total Ankle Replacement for Degenerative Ankle Disease
November 6, 2009 | Emerging Technology Reports
Proprietary Names: AGILITY LP Total Ankle Replacement System; Albatros; Alphanorm; Alpha OSG; Ankle Evolutive System (AES); Buechel-Pappas Total Ankle Replacement System; Bologna Oxford (BOX) Total Ankle Replacement; Ceramic Coated Implant (CCI) Evolution Ankle Prosthesis; Eclipse Total Ankle Implant; ESKA Ankle Endoprosthesis; German Ankle System; HINTEGRA Total Ankle Prosthesis; INBONE Total Ankle System; LCS; MOBILITY Total Ankle System; RAMSES Ankle Replacement; Salto Talaris Anatomic Ankle; Scandinavian Total Ankle Replacement System (STAR Ankle); Taric Ankle System; TNK Ankle; Topez Total Ankle; Zenith Total Ankle Replacement System; Thompson Parkridge Richards (TPR)
Total ankle replacement (TAR) involves the replacement of an injured or diseased ankle joint with an artificial joint. TAR (also known as ankle arthroplasty) is intended as an alternative to ankle fusion (also known as arthrodesis) in patients with debilitating end-stage arthritis, loss of ankle function, and pain that is refractory to conservative treatment. Ankle fusion is considered the standard of care for this patient population. However, a fused ankle joint may prevent flexion and extension of the foot and limit side-to-side motion. The purported benefit of TAR over ankle fusion is preserved range of motion (ROM).
Over the past three decades, TAR has been performed more frequently in Europe than the United States due to limits in distribution of the technology to skilled surgeons in orthopedic specialty centers. In the late 1970s and early 1980s, early failure rates within 5 to 10 years of implantation led to abandonment of the procedure for several years. In the 1990s, a better understanding of ankle motion led to modifications of first-generation fixed-bearing TAR implants, which consisted of two metal components that were usually cemented into the tibia (lower leg) and the talus (ankle bone) to restrict ankle motion. Developers aimed to prolong the TAR implant's useful lifespan and improve patient outcomes.
Currently marketed TAR implants differ from earlier generation implants in several ways. These differences include the required amount of bone resection and ankle joint resurfacing, the implant shape, anatomic fit, axes of rotation, and the type of ingrowth surface. Mobile-bearing implants have a third component (a polyethylene bearing) that glides between the two metal components. These mobile-bearing ankle implants do not require cement to implant, as they are porous-coated and more closely mimic the function of the natural ankle. Detailed descriptions of individual products and unique implantation...