The purpose of this study was to assess the biomechanical stability of the a total ankle arthroplasty system using longitudinal migration (LM) and inducible displacement (ID) measures. This study is the first study of its kind to assess total ankle arthroplasty (TAA) implant micromotion using model-based radiostereometric analysis (MBRSA). Twenty patients underwent TAA that implanted the Mobility(TM) (DePuy, Warsaw IN). The mean (SD) age was 60.4 (12.5) and BMI was 29.1 (2.8) kg/m2. One surgeon performed all surgeries. All patients included in this study had given informed consent. Capital Health Research Ethics Board had approved this study. Uniplanar medial-lateral RSA X-ray exams were taken postop (double exam), at six wk, three mth, six mth, one yr and two yr followup times using a supine, unloaded position. Standing medial-lateral exams were taken at three mth, six mth, one yr and two yr followup intervals. LM and ID micromotions were assessed using Model-based RSA 3.2 software (Medis specials, Leiden, The Netherlands). Implant micromotions (x, y, z, Rx, Ry, Rz, MTPM) were determined and assessed for each subject using model-based pose estimation, and the implant-based coordinate system. The Elementary Geometric Shapes module from the Model-based RSA 3.2 software was used to assess the micromotion of the tibial component spherical tip due to implant symmetry.Purpose
Method
The purpose of this study was to assess the clinical outcomes over two years for total ankle arthroplasty (TAA) using Short Form-36, Foot Function Index and Ankle Osteoarthritis Scores, and to compare these with radiostereometric analysis longitudinal migration and inducible displacement results. Twenty patients undergoing TAA implanting the Mobility Total Ankle System (DePuy, Warsaw IN) were assessed at 3mth, 6mth, 1yr and 2yr followup periods by model-based radiostereometric analysis, MBRSA 3.2 (Medis specials, Leiden, The Netherlands), for longitudinal migration (LM) and inducible displacement (ID). The same subjects completed clinical outcome questionnaires at these followup periods for Short Form-36 (SF-36; Physical Component Scores (PCS) and Mental Component Scores (MCS)), Foot Function Index (FFI) and Ankle Osteoarthritis Scores (AOS). Descriptive statistics and Pearson correlations (alpha = 0.05) were calculated using Minitab 15 (Minitab Inc., State College PA).Purpose
Method
To compare Radiostereometric Analysis (RSA) and subjective outcomes of Total Knee Arthroplasty (TKA) and Total Ankle Arthroplasty (TAA). Twenty-five patients were recruited to receive TKA (Zimmer, NexGen LPS Trabecular Metal Monoblock) and 20 patients were recruited to receive TAA (DePuy, Mobility). The tibial component of the TKA and the tibial component of the TAA were followed for two years with RSA with exams postoperatively at six, 12 and 24 months. At two years, inducible displacement RSA at the knee and ankle was also performed. RSA outcomes measured were translations in the anterior-posterior, medial-lateral and distal-proximal directions of both implants. SF-36 outcome questionnaires were completed preoperatively and at each RSA follow-up with the outcome being the mental component score (MCS) and physical component score (PCS). Analysis of variance statistical testing was used to compare RSA outcomes and subjective outcomes.Purpose
Method
