diff --git a/ProcessLib/LIE/HydroMechanics/HydroMechanicsProcess.cpp b/ProcessLib/LIE/HydroMechanics/HydroMechanicsProcess.cpp
index 74e54b29a9ebd12dccbf9cdc49e771e884245b8b..ec4e7134414e4c68c6f05831730a07d147ce8ac9 100644
--- a/ProcessLib/LIE/HydroMechanics/HydroMechanicsProcess.cpp
+++ b/ProcessLib/LIE/HydroMechanics/HydroMechanicsProcess.cpp
@@ -484,7 +484,7 @@ void HydroMechanicsProcess<GlobalDim>::computeSecondaryVariableConcrete(
 
         ProcessLib::SpatialPosition x;
         x.setNodeID(node_id);
-        vec_b[node_id] = w[GlobalDim == 2 ? 1 : 2] +
+        vec_b[node_id] = w[GlobalDim - 1] +
                          (*_process_data.fracture_property->aperture0)(0, x)[0];
     }
 }