Insert Position in Three-Component Total Ankle Replacement

Background: Total ankle replacement has become a valuable treatment option for end-stage osteoarthritis. The most recent generation of implants comprises a second interface between the polyethylene insert and the tibial prosthetic component. This may permit a better adaptation of position between the implant components and thereby prevent unphysiological loading of ankle ligaments and reduce polyethylene wear. To date, no available data have evaluated whether the relative position of talar and tibial implant components change over time. Materials and Methods: We assessed the radiographs of 368 ankles that underwent primary arthroplasty with a HINTEGRA (R) (Newdeal SA, Lyon, France / Integra, Plainsboro, NJ) ankle to determine the spatial relationship between talar and tibial components at the time of surgery and during followup. The mean time to final followup was 51.2 months (range 11 to 98). We analyzed the anteroposterior offset as the distance between the center of the tibiotalar joint and the longitudinal axis of the tibia. Results: The mean anteroposterior offset ratio was 0.0 +/- 0.06 (range -0.21 to 0.16), and it remained constant over time. Conclusion: Our data suggest that the latest three-component prosthesis functions similar to the two-component prosthesis, but we believe with an added advantage of allowing an individualized position of the polyethylene insert in response to the individual soft tissue load due to different ankle joint configurations.