[Matched pair analysis: Innex FIXUC vs. NexGen LPS]

Abstract

Aim: The aim of the present retrospective matched pair study was to compare the clinical results of patients undergoing total knee arthroplasty (TKA) with 2 different operation strategies: tibia first vs. femur first for ligament balancing and rotational alignment of the femoral component.

Methods: In this study 30 patients underwent TKA with the fixed bearing prosthesis Innex FIXUC between 2003 and 2005. In the same period of time the posterior stabilised prosthesis NexGen LPS was implanted in 123 patients. Out of these, 30 patients were matched to the 30 patients of the Innex group based on the parameters age, gender, height, weight and BMI. All implants were cemented. Clinical examination was rated using UCLA score, Knee Society score, Lequesne score for knees, a visual analogue scale (VAS) for pain and the Feller patellar score. Three patients in the Innex group were lost to follow-up, and 27 matched pairs could finally be analysed.

Results: At a mean follow-up of 25 months (Innex) and 3 years (NexGen) statistically significant differences (p < 0.05) with advantages for the NexGen were found in the UCLA activity score (4.9 vs. 5.9, p = 0.013), in part A (knee score) of the Knee Society score (78.9 vs. 91.0, p = 0.002) as well as the total score (153.9 vs. 173.2, p = 0.012), VAS (2.1 vs. 0.6, p = 0.003) and in the Lequesne knee score (5.7 vs. 3.6, p = 0.024). No statistically significant differences (p < 0.05) were found in the function score of the Knee Society score and the patellar score (Feller).

Conclusion: In the described setting there were functional advantages for the NexGen prosthesis (femur first) at a comparable revision rate. However, satisfactory results with the Innex FIXUC are possible, too.