No difference in patient-reported outcomes or range of motion between ultracongruent and posterior stabilized total knee arthroplasty: A randomized controlled trial

Purpose

Ultracongruent (UC) inserts were designed to overcome potential issues with posterior stabilized (PS) inserts, including bone resection, post-breakage, and patellar clunk syndrome. However, there remains a shortage of high-quality studies directly comparing this insert design to the established PS Total Knee Arthroplasty (TKA). This prospective randomized controlled trial (RCT) aimed to compare clinical outcomes, range of motion, and complications of UC and PS TKA.

Methods

Ninety six patients with primary knee osteoarthritis were randomly assigned to either the PS or the UC group. There were no significant differences between the groups regarding age, body mass index, sex, or Osteoarthritis grade. The measured outcomes were Knee Injury and Osteoarthritis Outcome Score (KOOS) and Range of Motion (ROM), recorded preoperatively and at 3 and 6 months postoperative. Both the patient and interviewer were blinded to the allocation group.

Results

Eighty one patients were included in the analysis, with a mean follow-up of 1.3 years. Both groups exhibited a gradual improvement in KOOS. Still, no statistically significant differences were observed between the groups during the follow-up examinations at 3 or 6 months in KOOS or range of motion. No complication occurred in either group during the follow-up period.

Conclusion

Both designs demonstrated comparable positive outcomes, reinforcing the viability of UC designs as an alternative to the well-established PS TKA.

Levels of Evidence

Level l, randomized controlled trial.