OUTCOME OF REVISION TOTAL KNEE ARTHROPLASTY USING CONSTRAINED CONDYLAR KNEE PROSTHESIS: MINIMUM 2-YEAR FOLLOW UP

Abstract

Constrained condylar knee (CCK) prosthesis offers an implant option for complex revision total knee arthroplasties in which stable varus-valgus constraint as well as rotational control is needed for severe bone defect and ligament insufficiency. The aim of this study was to evaluate the clinical and radiological outcome of CCK prosthesis in revision TKA.

Fify-one revision TKAs performed using CCK prosthesis between Jan. 1998 and Feb. 2006 were performed. The mean follow-up period was 5 years and 3 months (2 to 9 years) and the interval between initial and revision TKA was 8 years (4 months to 21 years). The mean age was 67 years. Range of motion (ROM), knee society (KS) score, hospital for special surgery (HSS) score, complication rate and failure rate was evaluated. The tibiofemoral angle and radiolucent line was also evaluated on plain radiograph.

The mean ROM improved from 81.9° to 102°. The mean KS score improved from 49.3° to 79.7°, and KS function score from 50.3 to 71.0 (P< .001). The mean HSS score improved from 50.7 to 78.7 (P< .001). Tibiofemoral angle improved from valgus 3.1° to valgus 5.6° (P< .001). Radiolucent line more than 2mm was observed around 4 femoral and 4 tibial components. Complications including 1 skin necrosis, 1 tibial tubercle nonunion, 2 infections, 3 periprosthetic fractures and 5 arthrofibrosis were observed. Overall rating was excellent or good in 88% at the last follow up.

Revision TKA using CCK prosthesis showed comparable results with other reports in average 5 years follow-up.