In previous post’s we talked about what a bunion is and how mild and moderate bunions are treated, most notably the Silver, McBride and Austin Bunionectomies were discussed. Today i will discuss the common procedure for more severe bunion deformities.
Treatment for severe bunion deformities becomes more complicated, requiring a period on non-weightbearing on the surgically corrected foot (unlike that of the mild and moderate bunion procedures).
A severe bunion deformity is diagnosed when the intermetatarsal angle is greater than 15 degrees. The intermetatarsal angle shown below in red.
as this angle increases in severe bunion deformities, the need to close down this angle to a more acceptable 0-8 degrees become important. An Austin bunionectomy cannot be used to correct such large angle, since the procedure is located so far away from the apex of the deformity. Therefore the best way to achieve correction of the deformity is to perform procedures closer to the apex, thereby utilizing the longer lever arm. These procedures are collectively known as “base bunion procedures”.
Base bunion procedures usually come in two flavors. The 1st is the closing base wedge osteotomy. In this procedure a wedge of bone is taken out of the bottom of the metatarsal and is then closed down, this allows the 1st metatarsal to swing inward, thereby closing down the intermetatarsal angle (as shown below).
The other commonly used procedure is the Lapidus. The Lapidus procedure is similar to the closing base wedge, with the only difference being the placement of the wedge being taken out. In the Lapidus the wedge is taken out even closer to the apex of the joint at the metatarsal-cuneiform joint.
both procedures require a period of non-weight bearing ambulation of about 6-8 weeks, and the use of bone screws and/or plates.