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This might sound funny but I'm doing my homework after the fact. My 72-year-old father had surgery over the weekend for a broken leg (just above the knee). Surgery included the use of a metal plate and screws to hold it all together. What can you tell me about the different types of hardware used for leg fractures in 70 year olds?
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Fixation devices (commonly referred to as hardware) for fracture repair range anywhere from a single nail to a complex series of screws, washers, nuts, and metal plates. The surgeon must decide which one to use for each patient.
There are many different types of fixation devices available. A recent study from Germany comparing four separate fixation devices with different interlocking patterns offers some helpful information. The researchers tested everything first on synthetic (manmade) bones before trying the same tests on human bones. The natural bone was from cadavers (bones preserved after death).
The four implant types put to the test included 1) a conventional locking bolt referred to as T2, 2) the Distal Femoral Nail or DFN, 3) a plate and screw model called angular stable plate or AxSOS, and 4) a Supracondylar Nail (SCN). Each one has its advantages and disadvantages.
Each fixation device was tested through repeated cycles of load until the bone was observed to deform or give five millimeters or more. Failure was defined as deformation of more than 2.5 mm. The fixation implants were tested using thousands of cycles.
The T2 is a simple bolt with two screws placed through it in. The bolt goes down through the broken bone. The screws go sideways through the bolt from one side of the broken bone to the other. The screws are slightly apart from each other and parallel to one another. The T2 design had the highest failure rate (first to fail).
The Distal Femoral Nail (DFN) is similar to the T2 in structure but one of the screws has a spiral blade design. The DFN was better than the conventional two-screw design (T2) but it had the least stability and the lowest stiffness. Bone fragments could move because there was no compression or force between the fragments.
The angular stable plate (AxSOS) had the greatest torsional stiffness. It was the third of the four implants to fail. This plate and screw design works well for bed bound patients who are not up and putting weight on the leg. The metal plate lengthwise along one side of the broken bone is held to the bone with a series of seven screws placed at different angles through the bone.
The final implant to fail was the Supracondular Nail (SCN). The SCN has a three-plane pattern of interlocking screws meaning the screws are inserted through the central bolt and bone from three different directions. This fixation device had the best strength and stability. The diagonal arrangement of the screws through the bolt gave the best fixation in the dense bone. Its use is advised for patients who are getting up and moving early after surgery for distal comminuted femoral fractures.
Surgeons know what type of fixation devices to use based on type of fracture, biomechanical properties of each implant, rehab schedule, and bone density. Such knowledge can help speed up recovery and prevent complications.
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*Disclaimer:*The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic. |
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