Results of MOBILITY Ankle Replacement

Total ankle surgery is becoming a valid alternative to an ankle fusion for people with severe ankle arthritis. Changes have been made in the implant designs in the past several years, which are showing encouraging results. The benefit for replacement over fusion is preservation of some ankle mobility and thus improved ankle function for all kinds of life activities. This study looks at clinical outcomes as well as patient reported outcomes following ankle replacement with the MOBILITY Total Ankle System. These outcomes were measured with several questionnaires pre and post operatively. There was a clinical outcome measure called the American Orthopaedic Foot and Ankle Society score (AOFAS) and a patient reported, quality of life survey called the 36-item Short-Form Health Survey. They also collected overall patient satisfaction, height, weight, age and details of other medical conditions.

There were 106 participants in this study with a mean age of 61.9 ranging from thirty-three to eighty-nine years. In this group there were fifty-six with a preoperative diagnosis of osteoarthritis, twenty-eight with posttraumatic arthritis, and twenty-two with rheumatoid arthritis. The group of patients with posttraumatic arthritis was significantly younger at 54.8 compared to the other two groups.

The results indicate that there was not much difference between the groups for most of scores at both the one and two year follow-ups, and that all groups showed improvement in the outcome scores. The AOFAS score increased by an average of fifty-three points, which is comparable to some other similar studies, indicating consistency in this score improvement. The Short-Form Health Survey was used to get a feel for the patients’ perception of their general health and improvement related to their ankle replacement surgery. The results here also showed improvement from pre to post surgery. The rheumatoid arthritis group did have slightly lower scores in this questionnaire, indicating possibly the impact of this disease process on overall quality of life.

There were a few complications as a result of the MOBILITY ankle replacement surgery in this study. The most common was a medial malleolar fracture at six patients. Other less common complications included persistent medial ankle pain, infection and distal tibial fracture. There was one revision, however this was following a trauma. In all groups only one patient had a fusion following the total ankle procedure. Two patients had unresolved medial ankle pain and were later diagnosed with medial impingement, and following surgery this pain was resolved.