2017 ISAKOS Biennial Congress ePoster #1218


Comparison of Stability and Clinical Outcomes Between Using Gradius and Multi-Radius Designs in Total Knee Arthroplasty

Jong-Keun Seon, MD, PhD, Prof, Gwangju, Jeonnam KOREA, REPUBLIC OF
Eun-Kyoo Song, MD, PhD, Prof., Gwangju KOREA, REPUBLIC OF
Je-Hyoung Yeo, MD, Gwangju KOREA, REPUBLIC OF
Dong-Hyun Lee, MD, Gwang-Ju KOREA, REPUBLIC OF
Cheng Jin, Fellow, Gwangju KOREA, REPUBLIC OF

Center for Joint Disease, Chonnam National University Hwasun Hospital, Hwasun, Chonnam, KOREA, REPUBLIC OF

FDA Status Cleared


In total knee arthroplasty, recently introduced GRADIUS design did not provide better mid-flexion stability compared with conventional multi-radius design.



Although a single-radius TKA is designed to have the theoretical advantages of mid-flexion stability, actual clinical outcomes and their meanings are controversial. Recently new design (so-called “GRDIUS design”) was introduced to address the unmet need of mid-flexion stability in TKA. We compared the intra-operative stability of knee during TKA using a navigation system between the GRADIUS femoral design and the multi-radius femoral design. We also compared clinical outcomes between two designs in TKA. The hypothesis of this study was that the GRADIUS design can provide a better intra-operative stability of knee arthroplasty and the better clinical outcome compared with those of multi-radius design in TKA.

Materials And Methods

One hundred patients included for this prospective study who had TKA with Attune PS (50 patients, DePuy Synthes) or Vega designs (50 patients, Aesculap) for primary degenerative osteoarthritis. The two groups did not statistically differ with respect to age, gender, range of motion before the operation, severity of the deformity, BMI and the follow-up period. The same surgical technique and rehabilitation protocols were used in both groups. After implantation of the final component with bone cement, the varus-valgus stability at 0°, 30°, 60° and 90° was measured using the navigation system in both groups. The Clinical outcome measures included the range of motion (ROM) of the knee, Knee Society (KS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and VAS score during stair climbing after minimum of 1 year follow-up from surgery.


The average varus-valgus laxity at 30° of knee flexion was 6.0° in the GRADIUS group, and was 5.5° in the multi-radius (MR) group without statistical intergroup difference (p=0.20). At 60° of knee flexion was also similar in both groups (6.8° vs 6.4°). There was no significant difference of the ROM in the 2 groups (p=0.07). The average KS scores were increased in both groups, from 50.9 to 91.3 in the Gradius group and 55.1 to 90.4 in the MR group, and there were no significant differences between 2 groups (p=0.21 and 0.51). The average WOMAC score in both groups significantly improved compared to the preoperative value (P < 0.05), but there was no significant difference between the two groups (p=0.24). At the last follow-up, the VAS score while going up and down the stairs was also showed no difference between two groups (p=0.72)


In total knee arthroplasty, recently introduced GRADIUS design did not provide better mid-flexion stability compared with conventional multi-radius design. Moreover, there were no significant differences in all clinical outcome parameters.