Clinical results of Hi-tech Knee II total knee arthroplasty in patients with rheumatoid athritis: 5- to 12-year follow-up

Abstract

Background: Total knee arthroplasty (TKA) is a common form of treatment to relieve pain and improve function in cases of rheumatoid arthritis (RA). Good clinical outcomes have been reported with a variety of TKA prostheses. The cementless Hi-Tech Knee II cruciate-retaining (CR)-type prosthesis, which has 6 fins at the anterior of the femoral component, posterior cruciate ligament (PCL) retention, flat-on-flat surface component geometry, all-polyethylene patella, strong initial fixation by the center screw of the tibial base plate, 10 layers of titanium alloy fiber mesh, and direct compression molded ultra high molecular weight polyethylene (UHMWPE), is appropriate for TKA in the Japanese knee.The present study was performed to evaluate the clinical results of primary TKA in RA using the cementless Hi-Tech Knee II CR-type prosthesis.

Materials and methods: We performed 32 consecutive primary TKAs using cementless Hi-Tech Knee II CR-type prosthesis in 31 RA patients. The average follow-up period was 8 years 3 months. Clinical evaluations were performed according to the American Knee Society (KS) system, knee score, function score, radiographic evaluation, and complications.

Results: The mean postoperative maximum flexion angle was 115.6°, and the KS knee score and function score improved to 88 and 70 after surgery, respectively. Complications, such as infection, occurred in 1 patient and revision surgery was performed. There were no cases of loosening in this cohort, and prosthesis survival rate was 96.9% at 12 years postoperatively.

Conclusion: These results suggest that TKA using the cementless Hi-Tech Knee II CR-type prosthesis is a very effective form of treatment in RA patients at 5 to 12 years postoperatively. Further long-term follow-up studies are required to determine the ultimate utility of this type of prosthesis.

Figure 1

A: Anterior view of the Hi-tech knee II prosthesis CR type component. Note the polyethylene geometry with flat surface. B: Posterior view of the Hi-tech knee II prosthesis CR type component. Femoral component demonstrating the porous titanium coating and have 6 fins at anterior portion. C: Anteroposterior radiograph of Hi-tech knee II prosthesis CR type. D: Lateral radiograph of Hi-tech knee II prosthesis CR type.

Figure 2

The Knee Society Roentgenographjc Evaluation System. A: Anteroposterior view of representative tibial component. B: Lateral view of representative tibial component. C: Lateral view of representative femoral component.