EFFECT OF DECREASING TIBIAL SLOPE ON THE EXTENTION GAP DURING POSTERIOR STABILIZED TOTAL KNEE ARTHROPLASTY

Abstract

The purpose of this study was to evaluate the effect of decreasing tibial slope on extention gap during posterior stabilized total knee arthroplasty. 110 posterior stabilized total knee arthroplasties were studied for 2 groups;

1. having flexion contractures(n=35),

2. having no flexion contracture(n=75).

In each group, we measured the decrease of tibial slope and frequency of additional distal femoral resecions that were done due to insufficient extension gap in comparison with flexion gap during posterior stabilized total knee arthroplasty. We also compared frequencies of additional distal femoral resections between 2 parts having more and less slope decrease in each groups.

In each group, tibial slope decrease were 8.7 degrees, 7.4 degrees(p=0.145) and frequencies of additional resection were 51.4%, 24%(p=0.005) in average. In 2 parts having more and less slope decrease in each group, frequencies of additional resection were 44.4% vs 58.8%(p=0.505), 13.2% vs 35.1%(p=0.032). Results suggested that more decrease of tibial slope reduced frequency of additional distal femoral resection during posterior stabilized total knee arthroplasty in group having no flexion contracture.

Decreasing tibial slope can be considered as a factor influencing on extension gap during posterior stabilized total knee arthroplasty. The estimation of predictable tibia slope decrease through preoperative radiologic findings can be beneficial in performing succeful posterior stabilized total knee arthroplasty.