Skip to main content

Table 3 Intraoperative steps for proper vertical gap opening at the osteotomy site

From: The 3-triangle method preserves the posterior tibial slope during high tibial valgus osteotomy: first preliminary data using a mathematical model

Steps for determining the gap width at the osteotomy site based on the algebraic model of Noyes

1. The desired angular valgus correction was determined based on preoperative weightbearing long leg radiographs.

2. Intraoperatively a controlled opening of the osteotomy was performed by measuring the gap width at two predefined points along the medial osteotomy site.

3. The first vertical gap width measurement was performed at the most medial point of the tibia, i.e. the most posteromedial point of the osteotomy. The vertical gap width at this point was assigned by the letter Y1.

4. To determine the vertical gap width Y1, the coronal tibial width was measured at the most posteromedial site of the osteotomy. The tibial width at this point is assigned by the letter X1. Based on the tibial width X1 and the preoperatively determined coronal valgus correction angle the vertical gap width at Y1 is calculated and the osteotomy was gradually opened until the calculated vertical gap width at Y1 was reached.

5. Another vertical gap measurement was performed at a more anteriorly located point along the medial osteotomy site, assigned by the letter Y2. The distance of the two gap measurement points Y2 and Y1 along the medial osteotomy site was measured, assigned L. Furthermore, the coronal tibial width at Y2 was measured, assigned X2. From the tibial width X2, the vertical gap width Y1 and the distance L the vertical gap width Y2 was calculated and the osteotomy is gradually opened at Y2 until the calculated vertical gap width was reached.

  1. Performed intraoperative steps for obtaining proper vertical gap opening at the osteotomy site according to the algebraic method proposed by Noyes.