Abstract
Background
Total ankle arthrpoplasty (TAA) was performed frequently for ankle deformity caused by rheumatoid arthritis (RA) and osteoarthritis (OA). TAA has some advantages over ankle arthrodesis in range of motion (ROM). However, loosening and sinking of implant have been reported with several prostheses, especially constrained designs. Recently, we have performed mobile bearing TAA and report short term results of this prosthesis followed average 3 years.
Method
20 total ankle prostheses were implanted in patients with RA (n=14) or OA (n=6) in 19 patients (5 male and 14 female, one bilateral), between 2005 and 2009. We used FINE total ankle arthroplasty that is mobile bearing system (Nakashima Medical Co., Ltd, Okayama, Japan). All patients were assessed for American Orthopaedic Foot and Ankle Society (AOFAS) score, ROM in plantar flexion and dorsiflexion at the point of pre-operation and final follow-up. We evaluated radiolucent line, sinking, and alignment of prostheses at final follow-up.
Results
At the operation, patients were, on average, 64.1 years old. The mean follow-up period was 34.0 (6∼55) months. We found excellent satisfaction and a significant improvement of AOFAS score. Plantar flexion and dorsiflexion also improved compared with the preoperative state, but not significantly (table 1). At final follow-up, five ankles (25%) showed radiolucent line around the components or sinking of prostheses. Three ankles (15%) was performed reoperation, due to early infection, progressive medial OA change by sinking, and loosening of the talus component.
Discussion
Radiolucent line around the components or sinking of prostheses occurred at high frequency (25%). But, only two ankles (10%) were had to reoperation, cause by pain. We take account of the fact that the symptom was lack in spite of radiological changes. Good clinical results can be achieved with FINE total ankle arthroplasty system. However, this series was short term of follow-up. We need to evaluate mid- and long- clinical results. Mobile bearing total ankle arthroplasty is a treatment option for RA and OA.
