The tension band technique converts a tensile force into a compressive force. This enables improved fracture healing, as stability is improved when tensile forces are reduced at the fracture site. Tension banding is particularly useful in the setting of fractures where a muscle pull produces distraction of the fracture fragments, such as fractures of the patella, olecrenon, greater tuberosity of the humerus, or greater trochanter of the femur. Tension bands can enable immediate motion at the involved joint, which allows for an improved functional outcome.
Tension banding is a principle and not a particular implant. To apply an implant with a tension band technique, a device is fixed eccentrically to the convex side of the fractured bone. Since a curved structure has a compression side and a tension side when an axial load is applied, the device on tension side neutralizes the forces under an axial load. The essential prerequisite is there must be cortical contact on the compressive side, which is the side opposite to the implant. If there is a cortical defect or comminution on the compressive side, the implant will undergo bending stress and be subjected to early fatigue failure.
A tension band can produce compression statically or dynamically. If a tension band produces fairly constant force at the fracture site during motion, such as at the medial malleolus, it is called a static tension band. Conversely, if the compression increases with motion, such as in the patella with knee flexion, the tension band is called dynamic.
The following prerequisites are essential:
1. There must be intact cortical contact on the side opposite the tension band.
2. The fixation must be able to withstand tensile force.
3. The bone or fracture pattern must be able to withstand compressive force.