Is the lateral tibial spine a reliable landmark for planning tibial or femoral valgus osteotomies?

Abstract

IntroductionA valgus osteotomy around the knee is a conservative procedure performed to unload the medial tibiofemoral compartment. However, the optimal postoperative alignment target remains controversial. Many studies have applied a “Fujisawa point” at 62.5%. The results of recent studies suggest decreasing the range of the mechanical axis target correction to 50–55%. The primary purpose of this study was to define the mean position of the lateral tibial spine in healthy patients from a reproducible 3-dimensional (3D) analysis. The study hypothesis was that the apex of the lateral tibial spine was a reliable and reproducible landmark for planning valgus osteotomies and preventing overcorrections. Materials and methodsThe study included 1140 patients: 560 women and 580 men, with a mean age of 61.7±16.5 years (18–98) and a mean body mass index (BMI) of 24.9±4.9kg/m2 (13.3–54.6). This analysis was done with the Stryker Orthopaedics Modeling and Analytics (SOMA) system which uses a database of computed tomography (CT) scans and 3D bone models. A statistical assessment was performed to determine the mean position of the lateral tibial spine. These measurements were then compared according to ethnicity, sex, age, BMI, knee side (right and left) and the overall mechanical axis of the leg. ResultsThe mean tibial plateau width was 72.9±5.7mm (59.1–91.1). The mean position of the lateral tibial spine was 53.6±1.1% (48.9–57.2). The mean position of the medial tibial spine was 48.4±2.5% (43.6–56.1) while the center of the tibial spines was 51.0±1.5% (46.4–56.1). Africans had a significantly more lateral mean tibial spine position than Asians (54.7% vs. 53.3%, p=0.001), Caucasians (54.7% vs. 53.7%, p=0.002) and Middle Easterners (54.7% vs. 53.6%, p=0.034). ConclusionThe lateral tibial spine is a simple and reproducible bony landmark. This landmark can be used when planning valgus osteotomies aiming for a “Fujisawa point” at 54%. Level of evidenceIV.