Comparison of Anterior-Stabilized and Posterior-Stabilized Total Knee Arthroplasty in the Same Patients: A Prospective Randomized Study

• Published in: The Journal of arthroplasty Vol. 34; no. 8; pp. 1682 - 1689
• Main Authors: Jang, Sung W., Kim, Man S., Koh, In J., Sohn, Sueen, Kim, Chulkyu, In, Yong
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.2019
• Subjects: anterior stabilized; outcomes; posterior stabilized; stability; Total knee arthroplasty; posterior stabilized; Total knee arthroplasty; anterior stabilized; outcomes; stability
• ISSN: 0883-5403; 1532-8406
• DOI: 10.1016/j.arth.2019.03.062

A highly conforming, anterior-stabilized (AS) insert is designed to provide anteroposterior (AP) stability of the posterior-stabilized (PS) insert without a post. The purpose of this study was to compare the static and dynamic stability and function of AS and PS total knee arthroplasty (TKA) in the same patients. A prospective, randomized controlled trial was performed in 45 patients scheduled to undergo same-day bilateral TKA. One knee was randomly assigned to receive an AS TKA, and the other knee was scheduled for a PS TKA from the same knee system. At 2 years postoperatively, the static AP stability was compared using anterior and posterior drawer stress radiographs at 90° knee flexion. Dynamic AP stability was evaluated using one-leg standing lateral fluoroscopic images throughout the range of motion. Knee function was compared using the Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index score. At 2 years postoperatively, there was a significant difference in knee AP laxity at 90° of flexion between the two groups (7.6 ± 3.9 mm in the AS group vs 2.2 ± 2.3 in the PS group, P < .001). However, there were no differences in dynamic AP stability under one-leg standing fluoroscopic lateral images at 30°, 60°, and 90° knee flexion (P = .732, P = .764, and P = .679, respectively). The Knee Society Score and Western Ontario and McMaster Universities Osteoarthritis Index scores were not significantly different between the two groups (P = .641 and P = .582, respectively). Despite the fact that the AS TKA group showed significantly more static posterior displacement than the PS TKA group at 90° of knee flexion, both the AS and PS TKA groups showed similar dynamic stability under weight-bearing conditions and knee function at 2 years postoperatively.