Discussion
anterior knee pain, valgus deformities, pain, varus deformities, TKA, MP
The most important finding in this study was that there was no difference in ROM or functional or radiographic outcomes between the 2 treatment groups at the short-term follow-up visit. Both options are safe and give satisfactory results. This is the first study to compare PCL retention and PCL resection in simultaneous bilateral TKA with MP implants. Therefore, we eliminated confounders such as differences in pain and subjective perceptions between individuals.There is ongoing debate on whether to retain or excise the PCL. Excision of the PCL leads to unpredictable laxity in flexion, resulting in less internal rotation of the tibia during flexion after TKA. However, PCL retention will maintain more of the tibia's internal rotation with the knee in flexion, optimizing patellofemoral tracking, but with a tighter flexion gap as a trade-off. Restoring native internal rotation of the tibia could minimize the risks of patellar tilt, lateral displacement, and anterior knee pain, which is needed to achieve high satisfaction after TKA. However, maintaining adequate flexion space could prevent loss of passive internal rotation of the tibia relative to the femur and anterior lift-off of the insert [The anteroposterior translation of the femur might influence range of motion. PCL preservation will result in better femoral rollback, which will increase the range of motion of CR implants [Good patient-reported outcome measures (PROMs) were reported with medial pivot prostheses [The FJS was considered the best measurement to evaluate high-end functionality post arthroplasty, and “forgetting the joint” may be the ultimate goal of arthroplasty [Based on this study’s results, retaining PCL in medial pivot TKA is safe and comparable with sacrificing the PCL. Nevertheless, this study has several limitations. First, the patient sample size was small and the follow-up period was short. However, this study was a double-blind study of bilateral simultaneous TKA. Comparing clinical outcomes to the contralateral knees in the same individual in simultaneous bilateral TKA could eliminate confounders such as differences in pain and subjective perceptions between individuals. Secondly, our study did not undergo age and gender matching, while in the previous studies, gender is associated with residual pain, which is still controversial, and age at surgery is also associated with residual pain. Thirdly, the same prosthetic implant was used in all patients. Different MP designs from other manufacturers might give different results. Finally, this study only included knees with varus deformities and excluded those with valgus deformities. Valgus deformity might have different effects due to different kinematics.