Cruciate substituting (CS) implants have seen increasing popularity for total knee arthroplasty (TKA). They aim to combine the bone preservation of cruciate retaining (CR) designs with the balancing ease of posterior stabilized (PS) implants. Improved polyethylene and congruent articular geometry also address prior concerns about wear and instability.

CS implants lack an intercondylar box cut, reducing bone resection versus PS designs. The tibial insert has a central post and dished articulation to provide anteroposterior stability akin to the posterior cruciate ligament (PCL). Ultracongruent polyethylene theoretically improves contact stresses.

CS TKA can utilize measured resection or gap balancing techniques. PCL release is recommended to independently balance flexion and extension gaps. More neutral tibial slope facilitates balancing without the PCL. Transitioning from PS designs, surgeons should note decreased posterior offset of some CS femoral components during balancing.

CS implants show less anterior translation versus PS designs in midflexion, but more anteroposterior laxity in deep flexion. They provide stability comparable to CR designs. Kinematics still differ from the native knee.

Multiple studies demonstrate no significant clinical differences between CS, PS and CR TKAs in terms of range of motion, clinical scores, and proprioception. Some show slightly better outcomes with CS implants.

Modern CS implants combine the strengths of CR and PS designs without clear disadvantages. Further study on kinematics, wear characteristics, and long-term outcomes is warranted. CS TKA is an excellent option for primary knee arthroplasty.