2017 ISAKOS Biennial Congress ePoster #1518

 

Evaluation of a New Preoperative Planning Technique for Medial Opening Wedge High Tibial Osteotomy

Elad Spitzer, MD, Shoresh, Israel ISRAEL
Joseph J. Ruzbarsky, MD, Aspen, CO UNITED STATES
John B. Doyle, BA, New York, NY UNITED STATES
Kaitlyn L. Yin, BA, New York UNITED STATES
Robert G. Marx, MD, New York, NY UNITED STATES

Hospital for Special Surgery, New York, NY, UNITED STATES

FDA Status Not Applicable

Summary

This study proposes a new digital pre-operative planning technique that achieves similar accuracy of the lateral bone hinge when compared to current methods, but exposes the patient, surgeon, and staff to significantly less intraoperative radiation.

Abstract

Background

The lateral bone hinge for medial opening wedge high tibial osteotomy is crucial. If the hinge is too small, the tibia can fracture and become unstable, requiring further fixation. If the hinge is too large, the osteotomy can propagate into the joint as an intra-articular fracture when opening the osteotomy. We propose a new technique that utilizes digital pre-operative templating to improve the accuracy of the cut for high tibial osteotomy to obtain a lateral cortex hinge of 10 mm.

Methods

10 cadaver extremities from 5 cadavers were matched into pairs and randomized into two groups: those with and without preoperative templating. The templating protocol uses an AP knee radiograph and measures from 5 cm below the medial joint line on the medial cortex to a point 1.5 cm below the lateral articular surface on the lateral cortex. The distance between these points on the medial and lateral cortices is measured and 20 mm is subtracted to determine the depth of the saw cut (10 mm for the hinge and another 10 mm because the proximal tibia is oval in shape). The control method was done by making the cut using fluoroscopy with tactile feedback. Post-operative CT scans were obtained of all legs to measure the width of the lateral bone hinge and compare it to the ideal of 10 mm. Intraoperative fluoroscopy used during both techniques and the numbers of fluoroscopy shots were recorded.

Results

We found neither the treatment group with pre-operative planning (P = .313) nor the control group using the conventional technique (P = .125) had bone hinge widths that were significantly different from the ideal 10 mm. The average hinge widths for the treatment and control groups were 11.2 and 11.5 mm, respectively. However, the treatment group with pre-operative planning was exposed to significantly less intraoperative fluoroscopy during the osteotomy cut. The average total number of fluoroscopy shots was 2.2 in the treatment group versus 6.3 for the control group (P = .03).

Conclusions

This new pre-operative planning technique achieves similar accuracy of the lateral bone hinge when compared to current methods but exposes the patient, surgeon, and staff to significantly less intraoperative radiation.