2015 ISAKOS Biennial Congress ePoster #1135

The Effect of Tibial Rotation on Knee Medial and Lateral Compartment Contact Pressure

Hamidreza Yazdi, MD, Tehran IRAN, ISLAMIC REPUBLIC OF
Hannes Behensky, MD, Salzburg AUSTRIA
Mohhamadreza Mallakzadeh, PhD, Tehran IRAN, ISLAMIC REPUBLIC OF
Behrooz Givehchian, MD, Tehran IRAN, ISLAMIC REPUBLIC OF
Hamidreza Daneshparvar, MD, Tehran IRAN, ISLAMIC REPUBLIC OF
Sara Farshidfar, MSc, Tehran IRAN, ISLAMIC REPUBLIC OF

Iran University of Medical science, Tehran, Tehran, IRAN

FDA Status Not Applicable

Summary: We demonstrated that 15° IR of the tibial shaft increased contact pressure and 15° ER decreased contact pressure over the knee medial compartment

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Abstract:

Purpose

The progression of knee osteoarthritis (OA) is determined in part by mechanical effects on local structures. The mechanical influences of limb malalignment on cartilage loss is well known, however the effect of rotational deformities on knee OA is not yet known. The aim of the current study was to evaluate the effect of tibial rotation on knee medial and lateral compartment contact pressure.

Methods

The left knees of six fresh whole body cadavers were used in this study. Fuji Film Prescale Super Low type film was used for contact pressure measurement. The films were inserted into the joint after arthrotomy. The cadavers were stabilized with a custom-made device and axial force of half body weight specific to each cadaver was applied to the plantar surface of the feet. The examination was repeated after osteotomy of the fibula and tibia, the tibia was then rotated 15° or 30° internally (IR) or externally (ER) and securely fixed. The resulting films were scanned and CP determined using appropriate software.

Results

The p-values for increased medial compartment contact pressure at 15° and 30° IR and 30° ER were 0.016, 0.025, and 0.025, respectively. For decreased medial compartment contact pressure at 15° ER, the p-value was 0.020. P-values for increased lateral compartment contact pressure at 15° and 30° ER were 0.010 and 0.030, respectively. In this compartment, contact pressure changes at 15° and 30° IR were not significant.

Conclusion

This experimental study demonstrated that 15° IR of the tibial shaft increased contact pressure and 15° ER decreased contact pressure over the knee medial compartment. In cases of valgus upper tibial osteotomy for knee medial compartment osteoarthritis, the pressure can be reduced more by some external rotation of tibia, but it should be evaluated by further studies.

Keywords: Knee; Contact pressure; Tibial rotation; Osteoarthritis