Summary

Comparative study on Single-radius and multi-radius knee prosthesis designs in patients with bilateral total knee arthroplasty.

Abstract

Introduction

Single-radius (SR) and multi-radius (MR) knee prosthesis designs each have theoretical advantages. The theory behind the multi-radius design is that it better replicates the normal knee anatomy, leading to improved functionality and, among other benefits, better patellofemoral joint mechanics. Comparative studies on populations with these two types of prostheses exist; however, we have not found reports of patients with bilateral total knee arthroplasty, with one knee using each of these systems.

Materials and Methods:: A retrospective evaluation of 22 total knee replacements in 11 patients, using SR (Triathlon® Total Knee, Stryker) and MR (Attune™ Primary Knee System, DePuy Synthes) prostheses.

Results

Both designs led to satisfactory outcomes. The MR design resulted in 3 cases of anterior knee pain, while none of the SR prostheses exhibited this issue. Despite this, patient-reported pain reduction improved significantly with no significant differences (SR: 8.45 to 1.18 vs MR: 8.64 to 1, p < 0.2745). Regarding functional outcomes, the improvement in both components of the Knee Society Score (KSS) was similar in both groups (SR: KSS1 from 43.54 to 81, KSS2 from 50.9 to 83 vs MR: KSS1 from 49.9 to 84.36, KSS2 from 57.4 to 89.27, p < 0.6517). Only 1 patient in the MR group required manipulation under anesthesia due to postoperative stiffness, while the remaining patients did not require additional surgeries.

Conclusion

Both prosthesis designs led to satisfactory outcomes in knee replacement surgery. The only difference reported was in anterior knee pain, which occurred in 3 knees with the MR design and none with the SR design, consistent with existing literature.