THE RELATIONSHIP BETWEEN TOURNIQUET TIME AND VALGUS DEFORMITY IN NAVIGATED TKA

Abstract

Valgus knees present a surgically demanding challenge. Dissimilar bone and soft-tissue deformities compared to varus knees complicate restoration of proper alignment, positioning of components, and attainment of joint stability. Our study examined the relationship between tourniquet time and valgus deformity.

A prospective study of all valgus knees were implanted over a 30 month period with Emotion Ortho-pilot version 4.2 Navigation system (BBraun Aesculap, Tutlingen). They were done by a single knee surgeon. Tourniquet times (TT) were recorded digitally with fixed timing criteria. The software recorded all pre- and post-operative deformities. We performed the lateral parapatella approach for all valgus knees. No patella resurfacing was done but all tibiae were cemented.

There were a total of 56 valgus knees (1° to 22°, Mean 5.9°, SD 4.9). The TT varied from 42 min to 121 min (mean 72 min, SD 17.4). There was a statistically significant relationship between TT and Valgus deformity. Tourniquet Time = 59.6 + 2.1 * Pre-operative Valgus (p= < 0.0001, R² = 36.4%)

Thirty six percent of the observations were explained by this analysis. Other factors will need to be considered in future studies. This equation can be used as a guide in the allocation of theatre time. It applies to a specific surgical team and we would expect different teams to have different coefficients. This may be useful in comparisons of different teams.