Discuss the tension band principles. Describe its clinical use in fracture management.

1. Definition and biomechanical basis

A tension band is an internal fixation construct that converts tensile forces acting across the convex surface of a fracture into compression at the fracture site. It is particularly useful when muscle contraction or joint loading tends to distract a fracture, while the opposite cortex or articular surface can act as a hinge. The classic construct is a figure-of-eight stainless-steel wire placed on the tension side of a fracture and anchored on either side of it.

The principle is based on the mechanics of an eccentric load. When a bone is loaded in bending, one cortex is subjected to tension and the opposite cortex to compression. If the tensile cortex is disrupted by a fracture, muscle pull may cause gapping and displacement. A properly positioned tension band resists opening of the tensile surface. During functional loading, the wire becomes tensioned and redirects the tensile force into compression across the fracture line. Thus, the fixation is not merely a method of holding fragments together; it is intended to make controlled loading beneficial to fracture compression.