title: Evaluating component migration after modular stem fixed-bearing total ankle replacement.
abstract: To date, no studies have evaluated implant migration after implantation of a modular stem fixed-bearing total ankle replacement. The purpose of the present report was to determine the inter-rater and intrarater reliability of our proposed measurement technique and to assess implant migration over time. Twenty consecutive patients (aged 59.3 ± 12.2 years) who had undergone implantation with this modern, third-generation prosthetic were included. To assess implant migration, measurements were made from non-weightbearing, postoperative radiographs immediately after surgery and again at 1 year and 2 years. Implant migration was defined as a change in implant location from the immediate postoperative radiograph. The proposed measurement technique appears to be a reliable method of assessing implant migration, evidenced by the high inter-rater reliability and intrarater reliability (intraclass correlation [2,1] 0.993 and intraclass correlation [1,1] 0.997, respectively). The mean implant migration was 0.7 mm at 1 year and 1.0 mm at 2 years. Time (r = 0.42) and gender (r = 0.31) were significant predictors of implant migration (R(2) = 0.27, p = .008). Therefore, we confirmed our hypothesis that implant migration would significantly increase over time and discovered that implant migration was greater in males (1.2 ± 1.1 mm) than females (0.1 ± 0.8 mm). Given the gross stability of the implant and lack of revision within the follow-up period, the measurements obtained could serve as clinical guidelines for acceptable implant migration in the short term. To determine the thresholds correlated with implant failure, future studies with long-term follow-up are warranted.
authors.affiliation: Fellowship Director, Foot and Ankle Reconstruction, Foot and Ankle Department, Coordinated Health, Bethlehem, PA. Electronic address: drsbrigido@mac.com.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Brigido
authors.affiliation: Fellow, Foot and Ankle Reconstruction, Coordinated Health, Bethlehem, PA.
authors.forename: Garrett M
authors.initials: GM
authors.lastname: Wobst
authors.affiliation: Fellow, Foot and Ankle Reconstruction, Coordinated Health, Bethlehem, PA.
authors.forename: Melissa M
authors.initials: MM
authors.lastname: Galli
authors.affiliation: Fellow, Foot and Ankle Reconstruction, Coordinated Health, Bethlehem, PA.
authors.forename: Scott T
authors.initials: ST
authors.lastname: Bleazey
authors.affiliation: Research Associate, Clinical Education and Research Department, Coordinated Health, Bethlehem, PA.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Protzman
mesh_terms: D000843:Ankle Joint / Q000000981:diagnostic imaging; D058737:Arthroplasty, Replacement, Ankle / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis; D010146:Pain / Q000503:physiopathology; D011475:Prosthesis Failure; D011859:Radiography; D013997:Time Factors
keywords: ankle joint surgery; joint prosthesis; osteoarthritis; subsidence; total ankle replacement (TAR)