Locking Plate in Proximal Tibial Fracture: A Correlation between the Coronal Alignment of Tibia and Joint Screw Angle

PURPOSE: The purpose of this study is to evaluate the relationship between the angle formed between the proximal most screw through the locking compression plate-proximal lateral tibia (LCP PLT) and the joint line, and to evaluate if this angle can be used intraoperatively as an assessment tool to determine normal alignment of the tibia in the coronal plane. MATERIALS AND METHODS: There are two parts to this study: in the first part, LCP PLT was applied to 30 cadaveric adult tibia. The angle between the joint line and the proximal most screw was measured and termed as the 'joint screw angle' (JSA). In the second part, 56 proximal tibial fractures treated with LCP PLT were retrospectively studied. Two angles were measured on the radiographs, the medial proximal tibial angle (MPTA) and the JSA. Their relationship was analyzed statistically. RESULTS: The average JSA was 1.16 degrees in the anatomical study. Statistical analysis of the clinical study showed that the normal MPTA had a direct correlation with an acceptable JSA. CONCLUSION: We therefore conclude that the JSA can be used intraoperatively to assess the achievement of a normal coronal axis.