The History of the STAR Ankle in the United States
The history of total ankle arthroplasty dates back to the 1970s with a rise in popularity of total hip and total knee replacement. Several different designs were released. These were generally cemented two-part prostheses that were non-anatomic. At intermediate follow-up of four or five years the ankles began to fail. By the mid 1980s total ankle replacement in the United States was abandoned. Many of these early ankle replacements were later removed and the ankle was fused. Thus, over a fifteen to twenty year period ankle replacement did not exist in the US and ankle fusion was really the only choice for patients with severe ankle arthritis.
The history of the Scandinavian Total Ankle Replacement (S.T.A.R.) in the United States dates back to 1998. Dr. Roger Mann of Oakland, California went to a conference in Denmark to give a lecture on ankle fusion where he heard lectures from Dr. Hocum Kofoed, the designer of the STAR. When Dr. Mann returned home, he called the first foot & ankle fellow he had trained, Dr. Michael Coughlin of Boise, Idaho. He convinced Dr. Coughlin that the STAR was probably the best ankle replacement he had seen, and together they should attempt to introduce the STAR in the United States.
Dr. Mann and Dr. Coughlin contacted LINK Inc., the company who manufactured the ankle and marketed it in Europe. This began the experience with the STAR that culminated in an FDA Pre-Market Approval (PMA) Study. Drs. Mann and Coughlin were the medical directors of the study and in 1999, they went before the FDA and presented the proposal. Given the uncertain history of total ankle replacement in the United States, it was felt that careful patient selection and accurate reporting was vitally important to protect patients. The pilot study was a comparative trial designed for 158 ankle replacement patients and 69 ankle fusion patients. After the initial eighteen month pilot study, the FDA granted permission for three series of 150 patients each to be implanted during the years 2002 to 2008.
In 2007, some seven years after the study was initiated, Dr. Coughlin, Dr. Mann, Dr. Saltzman (University of Utah), and Dr. Clanton (Vail, CO) addressed the FDA panel to review the data. It took another two years to complete the FDA approval process and in June 2009 the STAR ankle was released in the United States with the proviso of specific teaching courses for physicians who would implant the ankle. The lengthy period of the STAR approval study, and the estimated $25 million dollar cost to the LINK Company make it unlikely that any other three-part non-cemented total ankle will be authorized in the USA in the near future.
The FDA and Ankle Replacements in the United States
After the mid 1980s, when almost all total ankle arthroplasty implants were removed from the market, Dr. Frank Alvine of South Dakota, continued to work with an ankle model. This was a two-part model with a noncemented porous coat on the back of the prosthesis. Alvine's model was marketed as the 'Agility Ankle', and was the only option in the US for over a decade. It was approved by the FDA under a program called 510K, which allows an implant that is similar to another already authorized implant, to be authorized for use based on the notion that a similar implant is already approved. The 510K pathway has allowed for the introduction of other two-part ankle replacements during the last decade. The Salto Talaris Ankle (Tournier, Inc.) was a three-part design in Europe. It was altered to a two-part design for a US model and thus was authorized by the FDA. There are other three-part ankles in Europe that are being considered for a change to a two-part ankle so they may be authorized in the United States. At this time, the STAR is the only three-part uncemented ankle authorized by the FDA.