Influence of extension stem length and diameter on clinical and radiographic outcomes of revision total knee arthroplasty
Journal
BMC Musculoskeletal Disorders
Journal Volume
21
Journal Issue
1
Date Issued
2020
Author(s)
Abstract
Background: Extension stems provide stability to revision total knee arthroplasty (RTKA). Little is known regarding the relationship between stem characteristics and RTKA stability. We aimed to identify the relationship between canal filling ratio (CFR) and aseptic loosening following RTKA. Methods: We retrospectively reviewed demographics, radiographic parameters, and outcomes associated with RTKA performed between 2008 and 2013 in a tertiary hospital. The inclusion criteria were: revision for aseptic loosening, hybrid fixation, minor bone defect, Zimmer? LCCK prosthesis, and follow-up > 24 months. Using the modified Knee Society radiographic scoring system, radiographic prosthesis loosening was defined as a radiolucent line (RLL) score ? 9 on the femoral side or ? 10 on the tibial side. We utilized receiver operating characteristic (ROC) curve analysis to evaluate the cutoff value for stem length and diameter in terms of prosthesis loosening or not. Furthermore, CFR-related parameters were analyzed with logistic regression to clarify their relationships with prosthesis loosening. Results: Prosthesis loosening was detected in 17 of 65 patients included. On logistic regression analysis, male sex and severity of the tibial bone defect were associated with loosening. On multivariate analysis, male sex and bone defect severity were associated with loosening on the femoral side, while malalignment was associated with loosening on the tibial side. Protective factors included femoral CFR > 0.85, CFR > 0.7 for > 2 cm, and CFR > 0.7 for > 4 cm, as well as tibial CFR > 0.85. Conclusions: To minimize loosening post-RTKA, femoral CFR > 0.7 for > 2 cm and tibial CFR > 0.85 are recommended. Risk factors may include male sex, bone defect severity, and malalignment. ? 2020 The Author(s).
Subjects
Aseptic loosening; Canal filling ratio; Extension stem; Revision total knee arthroplasty
SDGs
Other Subjects
adult; aged; Article; bone defect; bone malformation; canal filling ratio; clinical effectiveness; controlled study; disease severity; extension stem diameter; extension stem length; female; follow up; human; knee radiography; major clinical study; male; medical parameters; musculoskeletal system parameters; outcome assessment; prosthesis loosening; retrospective study; risk factor; scoring system; sex difference; total knee arthroplasty; adverse event; biomechanics; convalescence; devices; diagnostic imaging; knee; knee prosthesis; knee replacement; middle aged; pathophysiology; prosthesis complication; prosthesis design; register; surgery; treatment outcome; very elderly; Aged; Aged, 80 and over; Arthroplasty, Replacement, Knee; Biomechanical Phenomena; Female; Humans; Knee Joint; Knee Prosthesis; Male; Middle Aged; Prosthesis Design; Prosthesis Failure; Recovery of Function; Registries; Retrospective Studies; Risk Factors; Treatment Outcome
Type
journal article