Analysis of the Effect of Tibial Stem Length on Coronal Plane Deformity of the Tibial Component in Total Ankle Arthroplasty

Abstract

Background:Coronal plane deformity is common in patients who undergo total ankle arthroplasty. The correction of this deformity is paramount to the long-term survival of the implant. Coronal plane correction is achieved with soft tissue balancing and, in some part, is maintained through articular geometry constraint. The purpose of this study was to assess the influence of tibial component stem length on the coronal plane stability.Methods:A consecutive case series of stemmed implants that met inclusion criteria were reviewed to determine the correction and maintenance of the correction of coronal plane deformity with special emphasis on the effect of modular tibial stem lengths of 2 and >2 segments. Twenty patients received a tibial component with 2 stem segments, and 23 patients received a tibial component with >2 stem segments. At an average patient age of 62.1 years at implantation, there was no significant difference between the 2 cohorts with respect to preoperative deformity or demographics.Results:Our case series had a mean coronal deformity of 5.7 degrees, with valgus being more common than varus. At a mean final radiographic follow-up of 266.3 days after the first postoperative weightbearing radiography, coronal deformity increased by 0.4 degrees ( P = .031). From the first postoperative measurement to the last postoperative measurement, there was no difference in mean coronal plane ankle deformity change between patients who received 2 stem segments and patients who received >2 stem segments ( t = −1.14, df = 41, P = .259).Conclusion:Coronal plane deformity had a tendency to recur, albeit at a much smaller angle than preoperatively. This recurrence of deformity did not occur because of tibial component movement. Tibial stem lengths of >2 segments did not influence the maintenance of correction of coronal plane deformity or the stability of the tibial component in the coronal plane.Level of Evidence:Level III, retrospective comparative series.

Long-Term Follow up of Correction of Moderate to Severe Coronal Plane Deformity With the Star Ankle Prosthesis

“…The use of a mobile versus fixed-bearing prosthesis in this setting remains a subject of debate. While this investigation exclusively employed a mobile bearing ankle, similar outcomes can be expected when a fixed implant is used provided that a well aligned ankle can be achieved [15,17] . Berlet et al determined that the length of the tibial stem did not influence the ability to maintain coronal deformity correction when using the INBONE II (Wright Medical, Arlington, TN) prosthesis [17] .…”

“…While this investigation exclusively employed a mobile bearing ankle, similar outcomes can be expected when a fixed implant is used provided that a well aligned ankle can be achieved [15,17] . Berlet et al determined that the length of the tibial stem did not influence the ability to maintain coronal deformity correction when using the INBONE II (Wright Medical, Arlington, TN) prosthesis [17] . This indicates that it is imperative to obtain congruency of the tibiotalar articulation at the time of implantation using soft-tissue and osseous procedures as necessary without relying on the implant itself to maintain correction.…”

“…Management of these deformities has varied with respect to the surgical algorithm utilized depending upon the degree of initial deformity and ability to achieve intraoperative correction [10,11,15,26] . Both intra-articular and extra-articular methods have been employed as well as fixed and mobile-bearing prostheses [15,[17][18][19] . However, data is sparse regarding the ability to maintain long-term correction and prosthesis viability.…”

Intermediate-term Patient-Reported Outcomes and Radiographic Evaluation Following Intramedullary- vs Extramedullary-Referenced Total Ankle Replacement

“…Improvements in the INBONE II design included a longer tibial tray option, additional 2 anterior 4-mm talar pegs, and a talar sulcus to improve the stability of the polyethylene articulation. 47 Although there are several studies that have shown favorable results with IM TAR, 1,4,24,29 there are no studies directly comparing IMr and EMr TAR. Thus, the purpose of this study was to report on the radiographic outcomes, clinical outcomes, and implant survivorship following extramedullary-referenced (EMr) vs intramedullary-referenced (IMr) total ankle replacement (TAR).…”