Bicruciate-stabilised total knee replacements produce more normal sagittal plane kinematics than posterior-stabilised designs

Abstract

Bicruciate-stabilised total knee replacement (TKR) aims to restore normal kinematics by replicating the function of both cruciate ligaments. We performed a prospective, randomised controlled trial in which bicruciate- and posterior-stabilised TKRs were implanted in 13 and 15 osteo-arthritic knees, respectively. The mean age of the bicruciate-stabilised group was 63.9 years (SD 10.00) and that of the posterior-stabilised group 63.2 years (SD 6.7). A control group comprised 14 normal subjects with a mean age of 67.9 years (SD 7.9). The patellar tendon angle (PTA) was measured one week pre-operatively and at seven weeks post-operatively during knee extension, flexion and step-up exercises. At near full extension during step-up, the bicruciate-stabilised TKR produced a higher mean PTA than the posterior-stabilised TKR, indicating that the bicruciate design at least partially restored the kinematic role of the anterior cruciate ligament. The bicruciate-stabilised TKR largely restored the pre-operative kinematics, whereas the posterior-stabilised TKR resulted in a consistently lower PTA at all activities. The PTA in the pre-operative knees was higher than in the control group during the step-up and at near full knee extension. Overall, both groups generated a more normal PTA than that seen in previous studies in high knee flexion. This suggested that both designs of TKR were more effective at replicating the kinematic role of the posterior cruciate ligament than those used in previous studies.

Bicruciate Substituting Design Does Not Improve Maximal Flexion in Total Knee Arthroplasty

“…Ward et al 4 investigated the same systems as those in the present study and found no clinical differences between the groups. A fluoroscopic evaluation of the bicruciate substituting system showed KSS values similar to those in the present study 2 .…”

“…It is hypothesized that the added mechanical constraints should guide the motion of the knee during flexion and extension. The in vivo kinematics and kinetics of the guided-motion design were close to normal [1][2][3][4] and fluoroscopy studies have shown that the anterior and posterior cam-post mechanisms were effective in restoring normal knee kinematic patterns 3,4 . Furthermore, the patella-tendon angle approximated normal values at full knee extension, in comparison with that in the conventional posterior stabilized design 4 .…”

“…Second, there were some indications that the design of the prosthesis negatively influences its kinematics 3,4 . Several serious adverse device effects were related to instability and excessive lateral patellar tilt (>10°) in the bicruciate substituting group, perhaps related to the design of the prosthesis.…”

In vivo kinematics of knee replacement during daily living activities: Condylar and post-cam contact assessment by three-dimensional fluoroscopy and finite element analyses

“…Fifteen patients (Table ) affected by primary knee osteoarthritis were implanted with a post‐cam fixed‐bearing prosthesis (Journey® Bi‐Cruciate Stabilized Knee System; Smith & Nephew, Inc, Memphis, TN). This design claims a better restoration of natural knee kinematics by means of a larger constraining effect, implied by the new post‐cam mechanism and by the original shapes of the medial and lateral condyles . At 6 months after surgery, all patients were evaluated clinically and by 3D video‐fluoroscopy in order to derive joint motion at the replaced knee.…”

Bicruciate-retaining total knee arthroplasty compared to cruciate-sacrificing TKA: what are the advantages and disadvantages?

“…Sacrifice of the ACL can result in abnormal kinematics. BCR implants have shown a more physiologic anterior femorotibial contact point and a greater posterior translation in motion compared to ACL-sacrificing implants [7][8][9][10][11]. Recently, Peersman et al [8] showed that changes by removal of the conforming meniscus and cartilage have more impact on tibiofemoral kinematics than different inlay sizes of a BCR TKA.…”