Pertinent Pearls On Brachymetatarsia Repair With Callus Distraction
- Michelle L. Butterworth DPM FACFAS
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When considering surgical intervention for the repair of brachymetatarsia, there are basically three main techniques to utilize: lengthening/slide osteotomy; osteotomy with insertion of bone graft; and callus distraction. Although I have utilized all of these techniques, callus distraction remains my procedure of choice for the surgical repair of brachymetatarsia.
Brachymetatarsia represents one of the best and most useful indications for callus distraction in the foot. With callus distraction, one performs an osteotomy and applies a distraction device in order to facilitate gradual lengthening of the bone and surrounding structures. This gradual lengthening process provides sufficient time for all of the soft tissues to adapt so one can minimize the risk of vascular insult.
Also keep in mind that callus distraction is a more forgiving procedure and the surgeon can control the amount of lengthening over time as opposed to being restricted to the degree of correction one achieves at the time of the surgery.
The surgical procedure itself is technically not that difficult but a few pearls will make execution easier. First, place all pins prior to making the osteotomy. It is very difficult to place pins in an unstable bone. There should be two pins distal to the osteotomy and two pins proximal to the osteotomy. The pins should be bicortical and parallel to one another. Also be sure to always place the pins through the external fixator frame, using it as a guide to ensure proper placement and avoid angulation of the pins.
Make the osteotomy perpendicular to the metatarsal in the proximal metaphysis. It must be through and through. Proceed to place all sutures prior to final frame application and have a good assistant in order to help avoid tangling of the suture around the pins. Finally, leave enough room between the inferior edge of the external fixator and the skin. This allows you to monitor for postoperative edema, apply appropriate bandaging and avoid skin irritation.
The timing of the distraction is paramount for a successful surgical outcome. For lesser metatarsals, a one-week latency period is recommended before beginning distraction. I have found that the ideal rate of distraction for lesser metatarsals is 5/8 mm per day. The patient turns 1/8 of a turn five times a day. Smaller, more frequent turning intervals result in efficient osteogenesis. One can adjust this rate as necessary according to distraction and callus formation you see on radiographs.
Once the metatarsal has reached its ideal length, discontinue the distraction process and allow the area to consolidate over the next few weeks. Once consolidation is complete, remove the frame and pins, and have the patient begin weightbearing.
It is of the utmost importance to cease the distraction process once the metatarsal has reached its optimum length. One of the most common complications with this procedure is dislocation of the metatarsophalangeal joint secondary to overlengthening of the metatarsal. When this occurs, additional surgery is typically necessary in order to obtain a good clinical result and a satisfied patient.
Ensuring Patient Understanding On Realistic Expectations And Postoperative Demands
One of the most common reasons for an unhappy or displeased patient postoperatively is that the toe is still shorter than he or she would like it to be. The surgeon must thoroughly evaluate the toe preoperatively. It is very common that the involved shortened metatarsal also has shortened phalanges in the toe in comparison to the other toes. The surgeon must identify this and discuss it with the patient pre-operatively. He or she must realize that once the appropriate metatarsal length is obtained, it cannot be lengthened anymore or complications will arise. It also may still be shorter in comparison with the other toes. If the patient does not understand this, the procedure is doomed to failure.
Perhaps one of the biggest tips I can share regarding this procedure is not necessarily regarding surgical technique but more along the lines of patient education.
The podiatric surgeon must thoroughly inform the patient about the deformity and ensure that he or she realizes the demanding postoperative course and potential complications. Unfortunately, there are a fair amount of complications associated with this procedure and although many of them are minor, one must adequately inform the patient.
Many patients are eager to pursue this surgery to improve cosmesis and they can be discouraged postoperatively if their toe is still shorter than they think it should be or if they have a thickened scar. A well-educated patient should understand the potential complications of the procedure and be able to weigh the risks and benefits of the surgery. If the patient then chooses to pursue the surgery, this knowledge should help him or her have realistic expectations. This will usually result in a happier postoperative patient and a higher degree of surgical success.
This is a demanding procedure postoperatively on both the surgeon and the patient. However, it can be a very rewarding surgery with limited complications if the surgeon is diligent in the surgical execution and the patient is diligent in the postoperative regimen.