Background: Mobile-bearing knee designs represent an alternative to conventional fixed-bearing TKA designs. We present the results of a prospective, long-term clinical follow-up study of the Rotaglide (Corin UK) rotating – translating platform total knee design.

Methods: Between October 1990 and December 1998, 326 primary consecutive knee replacements were performed in 260 patients (223 women and 37 men). The average age of the patients at the time of the index procedure was 66.84 years (range 20–82 years). Osteoarthritis was the etiologic factor in 297 knees (91.10%) and rheumatoid arthritis in 25 knees (7.66%). Twenty knees (6.13%) had previous operations (including 16 osteotomies). Both femoral and tibial components were cemented in all knees and the patellae were resurfaced in 199 knees (61.04%). The polyethylene (GUR 1050) mobile inlay was at that time sterilized by Gamma irradiation (2.5 Mrad), packed and stored in air permeable ‘paper bag’. Patients were evaluated at three and six months post operatively and yearly thereafter with use of the KSS. In addition, a radiographic analysis of the tibial, femoral, and patellar components was carried out at each interval and at the last assessment. Twenty four knees (7.36%) were excluded from the study out of which ten knees (3.07%) of eight patients who had died and fourteen knees (4.29%) of ten patients who were lost to follow up. Thus 302 knees (92.64%) were assessed clinically and radiologically in 242 patients. Average follow-up 12.13 years (range 9 to 17).

Results: Pre-operative KSS Knee score 30 (range, 22 to 56) and KSS function score 39 (range, 32 to 58) improved to 88 (range, 62 to 96) and 85 (range, 56–95) respectively. Knee alignment was achieved in 279 out of 302 knees (92.38%). Knee stability was achieved in 292 knees (96.68%). Knee flexion was improved from an average of 92 degrees pre-op to an average of 113 degrees post-operatively. Zonal radiographic analysis revealed fourteen (4.63%) instances of radiolucent lines, ten of which measured < 1 mm in width. None of these lines were deemed to be progressive. Four of the remaining knees with a radiolucent line > 2 mm followed-up carefully and three of them eventually were revised. There were twenty four (7.36%) failures that resulted in revision surgery. In seventeen (5.21%) of them the findings were those of worn out or broken polyethylene with no sings of metal wear or component loosening and therefore only polyethylene exchange was carried out. The other seven knees (2.15%) were totally revised. Kaplan-Meier survivorship using revision of polyethylene mechanical failure as the end point was 94.76%. Overall survivorship of the implant at seventeen years was 92.64%.

Conclusions: This mobile-bearing, total knee prosthesis was associated with a good survival rate and demonstrated clinical efficacy during the 9 to 17 years follow-up interval.