7/29/2019 Tibial Osteotomys

1/1

Abstract

Introduction

Results:

Methods

Discussion:

Upon arrival at EUREKA!, our project had already been begunby a former graduate student of Clemson University. Each

bone model had been created, cut, and potted, and the

surgical wedges had been cut to the specified sizes of 10,

12.5, 15, and 17.5 mm for each of the three bone sizes. Wewere challenged to complete the dataset and analyze the

results.

Correction of Varus and Valgus Knee Misalignments via Tibial Osteotomies

Acknowledgement: Clemson University and the Calhoun Honors College are gratefully acknowledged for support of the EUREKA! Program.

Presented at 2011 EUREKA! Poster Forum, Clemson, SC. August 26, 2011.

Victoria Baker1, Winston Reece1, Juan J. Rodrigo2, John D. DesJardins11Department of Bioengineering, Clemson University, Clemson, SC

2Steadman Hawkins Clinic of the Carolinas, Greenville, SC

Tibial osteotomies are procedures used mainly to correct

misalignments of the knee in the varus (bowlegged) or valgus

(knock-kneed) directions. Surgeons insert a wedge of varying

size on the medial side of the knee in varying angles in orderto raise one side of the knee and, therefore, correct the joints

alignment. Classically, surgeons chose wedge angle based

rough X-ray calculations and size based on available bone

donor stock. This project seeks to develop a comprehensiverubric for osteotomy size and angle selection based on

experimental measurement.

1. Construct a metal stand for stabilization of the bone models

and camera.2. Gather small, medium, and large size bones along with

corresponding wedges in sizes 10mm, 12.5mm, 15mm, and

17.5mm as specified by surgical guidelines.

3. Place the small bone in the stabilizing stand and begin withthe 10mm wedge fitting in normal anatomical position.

4. Using a digital camera, snap a photograph from the

superior, anterior, and lateral views of the bone.

5. Continue by rotating the wedge 8 times in the medial andlateral directions taking the three photographs at each

rotation.6. Repeat Steps 3-5 for medium and large bone models.

7. Conduct image analysis to determine the angle made bythe wedge at each rotation.

8. Create graphs for the data.

The project was originally begun after a surgeon requested research in

order to create a rubric for more exact measurements of wedge size and

angle for use in patients of various sizes. Prior to this project, the surgeonused only approximations and guesses as to what size and angle would be

most beneficial to aiding the patients misalignment. After completion of this

project, surgeons will have access to a more exact rubric for selection of

surgical wedges which will provide a more accurate surgical procedure andlonger lasting results.

As a result of our project, several charts and graphs were created as areference point for surgeons to choose the most beneficial wedge size and

angle for each patient. With these results, surgeries can be much moreprecise than previous procedures and hopefully, results will be much more

satisfactory and longer lasting.

During EUREKA!, our project has continued to progress towards its goal.

Over the past five weeks, we have collected an entirely new data set in

order to try to create more exact results for the surgical wedge rubric. With

the new data, the rubric will be more precise for future surgical procedures

and therefore, create better results for the patients.

Conclusion:

Pictures were taken in order to measure the angles formed by the

insertion of each wedge.

The following are the various wedges used for each bone. For each

the small, medium and large bones, there are four wedges in sizes10mm, 12.5mm, 15mm, and 17.5mm

Methods

0

5

10

15

20

25

30

-100 -80 -60 -40 -20 0 20 40 60 80 100

ValgusCorrection(Degrees)

-Anterior/+Posterior Wedge Rotation (Degrees)

Effect of Wedge Rotation and Height on Valgus Correction SMALL

Small 10 mm

Small 12.5 mm

Small 15 mm

Small 17.5 mm

-30

-25

-20

-15

-10

-5

0

5

10

15

20

25

30

-100 -80 -60 -40 -20 0 20 40 60 80 100

PosteriorTilt(Degrees)

-Anterior/+Posterior Wedge Rotation (Degrees)

Effect of Wedge Rotation and Height on Posterior Correction SMALL

Small 10 mm

Small 12.5 mm

Small 15 mm

Small 17.5 mm