Bone Plates in Orthopedics: Indications & Tension Band Principle

Bone plates are orthopedic implants that used in internal fixation of fractures. The plate is fixed to the bone by application of bone screws on both side of fracture. The hole medical equipment’s are provided by orthopedic equipment manufacturers in India.

Plating is widely used for fixation of diaphyseal fractures of upper extremity and articular and metaphyseal fractures.

Plates are now widely accepted with different standard techniques of osteosynthesis, throughout the skeleton. Different anatomical locations demand different sizes and shapes of plates.

For a plate to be effective means of fixation it should meet following requirements

  • It should be of appropriate thickness and width for the given bone
  • The plate must have symmetric and adequate hold on either side of the fracture
  • The plate must be closely opposed to the contour of bone. An overcontoured or prebent plate is an exception
  • The plate must neutralize all forces acting on the fracture i.e. bending, shear, compression and torque

Indications for use of Bone Plates

The use of plate is indicated:

  • When anatomical alignment must be restored correctly
  • Where the use of bone screws alone is inadequate
  • When load sharing may be achieved with confidence. If this can’t be guaranteed, then a bone graft may be added at the site of any deficit

The body areas where the conditions described above arise commonly rare:

  • Around joints- failure to restore a joint surface to its normal shape may lead to osteoarthritis because of uneven wear of joint surfaces.
  • In the bone of the forearm, which rotate about each other.
  • On the pelvis especially around the acetabulum
  • On the jaw and face

Other areas where plates are occasionally used include the femur and the tibia. However, these long bones are subject to large forces, so alternative techniques using intramedullary nails have been developed. Non-weight bearing long bones such as the humerus may be plated although nails are occasionally used in this site also.

Tension Band Principle of Plating

Bones are always loaded evenly along their axes – if they are not this is known as eccentric loading. This also can occur in a fracture if the soft tissues are stripped off one side while left one intact on the other. These factors produce a tendency for a loaded bone to distort more or one side than the other.

If a plate is fixed on the side tending to open- the tension side- then this will counteract the eccentric load, compressing the fragments together at the side under the bone plate. The eccentric load will continue to compress the fragments of bone together on the side of the bone opposite to the plate. In this condition the fracture is compressed throughout the bone cross-section and the plate suffers an equal and opposite force- tension.

The following criteria must be satisfied for a plate to act as a tension band:

  • The fractured bone must be eccentrically loaded
  • The plate must be placed on the tension side.
  • The plate must be able to resist the tensile forces.
  • The bone must be able to withstand the compressive force which results from the conversion distraction forces by the bone plate.
  • There must be a bony buttress opposite to the plate to avoid cyclic bending

The plate is acting as a tension band or device. Band compression may be achieved using wires and this technique is commonly used across the patella at the knee and around the olecranon of the elbow. In this case the wires are acting as a tension device.

The plate is placed opposite the tension side of the bone and will easily be deformed by fracture opening when eccentric loading is applied.

Wherever possible bone plates should be put on the tension side of a fracture. This is not always possible for anatomical reasons, such as the risk of tethering mobile structures such as tendons or the need to respect the blood supply of the bony fragments.

Siora Surgicals is one of the top trauma implants manufacturers in India. The website offer different rage of surgicalimplants products including asLarge Fragment Locking Compression Plate, Mini Fragment Implants, Multifix Tibia Nails, Small Fragment Locking Implants, Bone Screws, Locking Plates, Trauma Bone Plates, AFN Nailing System, Cannulated Screws, Hip Prosthesis, Dynamic Hip Screw, Dynamic Condylar Screw, Interlocking Nails, Intramedullary Interlocking Nails, Proximal Femoral Nailing Antirotation, Angled blade plates etc.

Leave a Reply

Your email address will not be published. Required fields are marked *