Secrets To Managing Complications Of First MPJ Fusion
- Volume 19 - Issue 6 - May 2006
- 60267 reads
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Inside Insights On Fixation Hardware
There are many internal fixation constructs available and, for the most part, all of them work. What did surgeons do 40 years ago? There were no screws but they got the great toe joint to fuse with large diameter pins. Sometimes, I do think we get hung up too much on technology. Always remember that good dissection, stable fixation and proper postoperative care will yield a fusion.
Some examples of fixation techniques for the first MTPJ fusion include Steinman pins, crossing K-wires, bone staples, crossing screws, various plate systems and any combination thereof. Traditionally, surgeons have employed 1/3 tubular plates but these are bulky, often become irritating and have to be removed. Some have advocated maxillofacial plates because of their low profile but I have found they are generally too thin and break or fail easily.
In recent years, specialty plates have been designed for the first MTPJ fusion. These plates are pre-bent and angled to facilitate application without having to fumble around with bending irons on the back table. I generally will not rely on a plate alone but will use at least one lag screw across the fusion site for compression. Then I apply the plate in a neutralization application.
The ultimate goal for any fusion fixation is to maintain bone-to-bone apposition, stability and compression if possible. I personally recommend screw fixation and having at least two points of fixation. This can be crossing screws or a screw and a K-wire. This prevents axial rotation around one point of fixation. When implementing crossing screws, the concept of “stacking” screws is important so the surgeon has one screw more dorsal and the other more plantar to achieve compression over a larger surface area. The medial side of the joint is more accessible. Accordingly, the usual approach involves inserting a screw from the medial phalanx to the lateral metatarsal head and one screw from the medial metatarsal head to the lateral side of the phalanx.
If feasible, it is best to have the screws cross at the fusion site for a stronger construct. I will generally use 4.0-mm cancellous screws. However, it is a perfectly acceptable to use 2.7-mm or 3.5-mm cortical screws. Plates do not provide any compression but one may use these as a neutralization application. Plates are generally recommended if clinicians are performing a revisional surgery or using an interpositional tricortical bone graft. For primary fusions, plates are not necessary but certainly can help provide a very stable fixation construct. The drawback, however, is that there is a lot of hardware in an area where there is not a lot of subcutaneous tissue so it can be a source of irritation and may need to be removed.
Hardware failure may occur during the initial postoperative period. This is usually due to improper technique or surgeon error. This is true for any case using internal fixation. Examples include but are not limited to using cortical screw fixation and not purchasing the far cortex; lagging a screw without proper over drilling or failure to have screw threads beyond the fusion site; inability to get good bone purchase/compression; or inadequate stabilization. Sometimes, however, good surgery can be undermined by patient non-compliance.
Always remember, if there is broken hardware or radiographic lucency around screws, there is probably motion at the fusion site. This is a recipe for a non-union. When one notes motion during the initial stages of the postoperative period, consider placing the patient in a cast and make him or her non-weightbearing. Otherwise, one will probably end up revising the fusion.