The radiological accuracy after primary total knee arthroplasty - a single surgeon's serie

Abstract

INTRODUCTION: It is uncertain whether similar radiological outcomes can be achieved with different instrumentation systems after total knee arthroplasty (TKA). We compared the accuracies of limb alignment and components position between different TKA instruments, with special interest in the anterior versus medial tibial cutting guides. MATERIALS AND METHODS: A single surgeon series of primary TKA performed between 2011 and 2015 was reviewed. A total of 126 knees in 109 patients (90 female, 19 male) were included in the analysis. Pre- and post-operative lower limb mechanical axis, femoral and tibial components position in the coronal and sagittal planes were measured on the radiographs. Total knee arthroplasty instrumentations were classified into 2 groups based on the orientation of the tibial cutting guide: anterior (n=72) and medial (n=54). Scale data were analysed using independent-samples t test and nominal data were analysed using Chi-squared test. RESULTS: The mean (± standard deviation) age of patients was 69.3 ± 8.8 years. The mean operating time was 65 ± 14 minutes. Medial tibial cutting guides resulted in more valgus postoperative lower limb alignment and tibial component position compared with anterior guides (p=0.032 and 0.024, respectively). However, there was no difference in terms of the incidence of radiological outliers (>±3° of the desirable alignment) in all measurements between the 2 groups. DISCUSSION AND CONCLUSION: Total knee arthroplasty with medial tibial cutting guides resulted in more valgus postoperative alignment and tibial component position, although the difference was small and may not translate into clinical significance.