Summary

The distance from the joint line where the osteotomy will begin must be considered, because a lower medial cut starting point could increases the posterior slope in opening-wedge high tibial osteotomy

Abstract

Purpose

Open-wedge high tibial osteotomy is not without complications. Among others, the potential modification of the posterior tibial slope after this procedure is relevant.
The objective of this study was to evaluate the effects on the posterior tibial slope using different distances from the joint line to start the osteotomy and by varying the placement of the opening wedge.
We hypothesize that distalizing the starting point of the osteotomy in the medial tibial cortex and an incorrect location of the tibial opening wedge may increase the resulting posterior tibial slope.

Methods

A cadaveric study was conducted using 12 knees divided into two groups: 3 and 4 centimeters. The preintervention posterior tibial slope was measured radiologically. Depending on the group, the osteotomy began 3 or 4 centimeters from the joint line. The rest of the procedure did not differ between the groups. Once the osteotomy was performed, the medial cortex of the tibia was divided into thirds, namely, anteromedial, medial, and posteromedial. A 10° opening wedge was sequentially placed in each third, and the effect on the posterior tibial slope was evaluated radiographically.

Significance

was established with values of p < 0.05. Chi-square tests and Student’s t tests were used for analyses according to the study variables. The degree of correlation was evaluated by calculating Pearson’s correlation coefficient.

Results

When performing the posterior tibial slope analysis stratified by groups, significant changes were observed only in the 3 centimeters group (p = 0.02) when the wedge was placed in the anteromedial zone. In contrast, in the 4 centimeters group, differences were significant when the opening wedge was placed at both the medial (p = 0.04) and anteromedial (p = 0.012) zones. The inter and intra-rater reliability were excellent (Intra-class correlation coefficient = 0.82 and = 0.91, respectively).

Conclusion

Avoiding a low point when beginning the osteotomy and placing the opening wedge in the posteromedial third of the tibia allows correct control of the posterior tibial slope when performing an opening-wedge high tibial osteotomy.