Review Question - QID 8168

Locking plate technology allows for the creation of a fixed-angle construct, which can result in less angulation in comminuted metaphyseal fractures. While a variety of indications for the use of locking plates exist, given the above scenarios, this fixation strategy would be most strongly indicated for the treatment of a metaphyseal proximal tibia/distal femur fracture in osteoporotic bone (Answer 2). The other scenarios listed represent weaker indications for the utilization of a locking plate.

A variety of plates are available for the treatment of fractures. Compression plates utilize cortical screws placed eccentrically in a plate to achieve compression across simple fractures in order to promote primary healing. Locking plates, in which the screw head threads and locks into the plate, create a stiff, fixed-angle construct which is advantageous in certain fracture patterns. Specifically, metaphyseal fractures in osteoporotic bone represent a strong indication for the use of locking plates and screws. Other indications include fractures that require indirect reduction, bridging severely comminuted fractures in osteoporotic bone, and plating fractures where anatomical constraints prevent plating on the tension side of bone (e.g. short segment fixation). Many locking plates also have aiming arms, which allow for the percutaneous placement of proximal/distal screws. It is important to note that both locking and non-locking plates can be used in a bridging construct.

Bicortical locking screws are noted for the high resistance to applied forces, which is most pronounced in torsion. If interfragmentary motion is desired, a far cortical locking screw can be placed, although these and unicortical locking screws exhibit lower resistance to torsion than bicortical locking screws. Locking plates can also be placed and fixed percutaneously, although this technique does increase the chance of malunion, albeit at the benefit of less soft-tissue stripping. Recently, hybrid plates have been developed and brought to market, allowing for surgeons to leverage the benefits of both locking and non-locking screw fixation techniques.

Anglen et al. provide a review on the use of locking plates for extremity fractures. Their study pooled the results from 33 peer-reviewed studies. Overall, the authors found a paucity of strict indications for the utilization of locking plates, and note that patient- and fracture-specific factors play the most important role in deciding whether or not to use this strategy during fracture fixation.

Cantu et al. provide an overview on the use of locking plates in fracture care. The authors state that, in their opinion, the following five indications for the use of locking plates exist:
1) metaphyseal and intra-articular fractures
2) highly comminuted fractures involving metaphyseal bone
3) osteoporotic bone
4) proximal tibia and distal femur fractures
5) periprosthetic fractures.
The authors conclude that the expansion of this technology has greatly expanded the armamentarium of fracture surgeons, and has helped to improve the healing rates of these oftentimes catastrophic injuries.

Figure A demonstrates a comminuted ulnar shaft fracture. Figure B demonstrates a comminuted proximal femur fracture. Figure C demonstrates a bicondylar tibial plateau fracture. Figure D demonstrates a supination-adduction ankle fracture. Figure E demonstrates a spiral humeral shaft fracture.

Incorrect Answers:
Answer 1: This comminuted ulnar shaft fracture in a young patient is best treated through the application of a bridge plate. Since the ulna will be exposed during surgery, and the patient has good bone quality, a standard nonlocking plate could be used to bridge this fracture. While a locking plate could be used, it is not strongly indicated.
Answer 2: This comminuted proximal femur fracture would be best treated with an intramedullary nail +/- cerclage.
Answer 4: This supination-adduction ankle fracture would be best treated with a buttress plate on the medial side and a distal fibula plate on the lateral side. A buttress plate is often placed with nonlocking screws and while locking screws may be used distally in the lateral malleolus, these will most likely be placed into a hybrid plate, as cortical screws will be utilized proximally.
Answer 5: This spiral humeral shaft fracture would be best treated with a non-locking plate or an intramedullary nail.