Long-term outcomes of one single-design varus valgus constrained versus one single-design rotating hinge in revision knee arthroplasty after over 10-year follow-up

Abstract

Background The appropriate degree of constraint in knee prosthetic revision is unknown, necessitating the use of the lowest possible constraint. This study aimed to compare the long-term clinical and survival results of revision with rotation hinge knee (RHK) VS constrained condylar constrained knee (CCK) implants. Methods Overall, 117 revision case were prospectively reviewed and dividing into two groups based on the degree of constraint used, using only one prosthetic model in each group (61 CCK vs 56 RHK). All implants were evaluated for a minimum of 10 years. Survival of both implants at the end of follow-up, free from revision for any cause, aseptic loosening, and septic cause was compared. Results Better results were seen with use of the RHK in joint ranges of (p = 0.023), KSCS (p = 0.015), KSFS (p = 0.043), and KOOS (p = 0.031). About 22.2% of the cases required repeat surgery (11.7% RHK vs 29.6% CCK, p = 0.023). Constrained condylar implants had a significantly lower survival rates than rotating hinge implants (p = 0.005), due to a higher aseptic loosening rate (p = 0.031). Conclusion Using a specific RHK design with less rotational constraint has better clinical and survival outcomes than implants with greater rotational constraint, such as one specific CCK.

Condylar constrained and rotating hinged implants in revision knee arthroplasty show similar survivorship and clinical outcome: a systematic review and meta‐analysis

“…These differences can be attributed to the selection criteria imposed in our analysis. The reported differences in failure mechanisms between both groups in this meta‐analysis are not clinically relevant, thereby minimising potential biases [2].…”

“…6 Bar diagraphs showing the difference between CCK and RHK for preoperative, postoperative and difference between both for KSCS (A) and KSFS (B), reported according to Insall [14]. *p < 0.05; **p < 0.001 more constrained in the coronal plane compared to a CCK, as the CCK design offers less rigidity during varus-valgus movements [2]. This constraint in the coronal plane could lead to aseptic loosening in the long term in the RHK group due to repeated cycles of stress at the bone-implant interface.…”

“…Commonly used implants in revision surgery, ranked in order of increasing constraint, include the posterior stabilised (PS) design, condylar constrained knee (CCK) and rotating hinged knee (RHK). Generally, it is recommended to select the least constrained implant to maintain the intended soft tissue influence on the kinematics and minimise excessive stress at the bone–implant interface [2]. In case of severe bone defects and/or the absence of any ligaments, an RHK becomes necessary to restore stability.…”

“…In case of severe bone defects and/or the absence of any ligaments, an RHK becomes necessary to restore stability. For moderate to severe bone loss and ligament insufficiency, a constrained prosthesis such as a CCK or RHK has been advocated [2]. Whether a CCK or an RHK should be used to achieve a well‐balanced and stable knee is still a subject of debate [3].…”

Clinical Outcomes and Complications of 2-Stage Septic Versus Aseptic Revision Total Knee Arthroplasty

“…Fourth, the prosthesis designs and surgical protocols used in the septic and aseptic revision TKAs differed among the studies. The prosthesis design (degree of constraint) affects range of motion and stability after revision TKA 39,40 . Moreover, the time interval between the first and second stages of septic revision TKAs may affect outcomes such as the reinfection rate or range of motion 41,42 .…”