Essential Insights On Treating End-Stage Ankle Arthritis

Author(s): 
John F. Grady, DPM, FASPS, Sarah Mahowald, DPM, and Donald Graves, DPM

A Retrospective Review Of 100 Procedures With The Agility LP Total Ankle System

In his own study, the lead author first began doing FDA-approved ankle arthroplasty with the Agility LP Total Ankle System (DePuy). This system had complications that are not as common in more recently developed ankle replacement systems. For example, failure of a syndesmotic fusion was a common complication with the Agility system whereas more recently developed ankle replacement systems do not have the requirement for a tibial/tibular syndesmotic fusion concurrent with their implantation.

   Other complications with the Agility system include both medial and lateral malleolar fractures as one would have to perform an ostectomy to incorporate an Agility ankle replacement device. This led to stress risers that would often cause fractures. Additionally, other system failures included subsidence, which was caused by a number of flaws in this initial system such as a smaller talar component that would have extra pressure exerted on it due to surgeons having to implant the device with a distraction technique. Additionally, complications occurred because of maneuvering with the distraction technique, which could lead to everything from wound healing problems to release.

   Given these issues, the lead author suggests taking a harder look at the data as well as the results of ankle replacement surgery, and consider that more recently developed models have far lower complication rates and far greater success rates than previous models.

   In addition, we must continue to keep in mind that surgeons who are excellent at ankle arthrodesis and are currently evaluating arthroplasty in comparison to arthrodesis may not be excellent ankle joint replacement surgeons. In addition, we can’t emphasize enough the learning curve that exists with ankle replacement. Those who are good at hip and knee replacement may not necessarily excel at ankle arthroplasty and a surgeon who is good at ankle arthrodesis may not necessarily be good at ankle arthroplasty.

   In the lead author’s own retrospective review of results in the first 100 Agility total ankle replacements that occurred between 1998 and 2005, the patient’s age ranged from 29 to 76. The average patient age was 54 years. The average follow-up time was 73.5 months. The minimum follow-up time was five years. There were 83 cases of post-traumatic osteoarthritis, 11 cases of rheumatoid arthritis and six cases involving other types of arthritis. Failed conservative care therapy included ankle bracing, cortical steroid injections, ankle-foot orthoses, physical therapy modalities and ankle arthroscopy.

   The average pre-op pain was 8.4/10. The average pre-op range of motion with dorsiflexion was -1.3 degrees and plantarflexion was 5.67 degrees. The average post-op pain was 1.4/10 or an 85 percent reduction. The average post-op range of motion with dorsiflexion was 9.29 degrees and plantarflexion was 24.28 degrees. The total range of motion was 33.57 degrees or a 400 percent increase.

   Complications included malleolar fractures (10), talar component rotation (2), tibiofibular diastasis (4), bone growth around implant (4), wound dehiscence (2), lateral malleolar fracture (6), lack of dorsiflexion (2), DVT (1), arterial thrombus (1), varus deformity (3) and infection (3). In most of these cases, we were able to address these complications (such as a fractured malleolar) either intra-operatively or postoperatively (such as fractured malleoli that were repaired postoperatively or immobilized until they healed). In addition, some of these cases involved more than one complication in a single patient.

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