Revision total knee arthroplasty for flexion instability

Abstract

Aims We have previously reported the mid-term outcomes of revision total knee arthroplasty (TKA) for flexion instability. At a mean of four years, there were no re-revisions for instability. The aim of this study was to report the implant survivorship and clinical and radiological outcomes of the same cohort of of patients at a mean follow-up of ten years. Methods The original publication included 60 revision TKAs in 60 patients which were undertaken between 2000 and 2010. The mean age of the patients at the time of revision TKA was 65 years, and 33 (55%) were female. Since that time, 21 patients died, leaving 39 patients (65%) available for analysis. The cumulative incidence of any re-revision with death as a competing risk was calculated. Knee Society Scores (KSSs) were also recorded, and updated radiographs were reviewed. Results The cumulative incidence of any re-revision was 13% at a mean of ten years. At the most recent-follow-up, eight TKAs had been re-revised: three for recurrent flexion instability (two fully revised to varus-valgus constrained implants (VVCs), and one posterior-stabilized (PS) implant converted to VVC, one for global instability (PS to VVC), two for aseptic loosening of the femoral component, and two for periprosthetic joint infection). The ten-year cumulative incidence of any re-revision for instability was 7%. The median KSS improved significantly from 45 (interquartile range (IQR) 40 to 50) preoperatively to 70 (IQR 45 to 80) at a mean follow-up of ten years (p = 0.031). Radiologically, two patients, who had not undergone revision, had evidence of loosening (one tibial and one patellar). The remaining components were well fixed. Conclusion We found fair functional outcomes and implant survivorship at a mean of ten years after revision TKA for flexion instability with a PS implant. Recurrent instability and aseptic loosening were the most common indications for re-revision. Components with increased constraint, such as a VVC or hinged, should be used in these patients in order to reduce the risk of recurrent instability. Cite this article: Bone Joint J 2022;104-B(10):1126–1131.

Effect of Posterior Cruciate Ligament Resection on Gap Balancing in Robot‐assisted Total Knee Arthroplasty

“…In the knee joint, four major ligaments, the anterior cruciate ligament (ACL), the posterior cruciate ligament (PCL), the lateral collateral ligament (LCL), and the medial collateral ligament (MCL), altogether play very important roles in knee stability and kinematics. Inadequate correction of soft tissue imbalances, unbalanced flexion–extension gaps, and knee instability after primary TKA are major contributing factors to early TKA failures 7,8 . While the LCL and MCL are kept intact to maintain joint stability in knee arthroplasty, the ACL is usually removed regardless of whether it is a posterior‐stabilized (PS) or cruciate‐retaining (CR) knee prosthesis.…”

“…Inadequate correction of soft tissue imbalances, unbalanced flexion–extension gaps, and knee instability after primary TKA are major contributing factors to early TKA failures. 7 , 8 While the LCL and MCL are kept intact to maintain joint stability in knee arthroplasty, the ACL is usually removed regardless of whether it is a posterior‐stabilized (PS) or cruciate‐retaining (CR) knee prosthesis. The PCL, as the strongest ligament in the knee joint, plays a critical role in restricting posterior tibial displacement and stabilizing the knee.…”