A chevron osteotomy is a type of surgery that is used in the treatment of hallux valgus deformity, more commonly known as a bunion. Hallux valgus occurs when pressure is exerted on the big toe of the foot, often by footwear, causing the big toe to bend toward the other toes. As the toe bends, a bump can develop on the side of the metatarsal bone of the big toe. A simple bunion can be treated effectively with corrective footwear, but this is not appropriate for a more severe deformity. To correct this problem, a chevron osteotomy can be performed to properly realign the toe.
Surgery to correct a hallux valgus deformity is carried out in two stages. First, an exostectomy is performed to remove the bunion. In this part of the procedure, the lump of bone forming the bunion is shaved away, layer by layer. The next part of the procedure is an osteotomy, in which the metatarsal bone is cut and realigned to its normal position.
In a chevron osteotomy, the bone is cut at the distal end, which is the end closest to the tip of the big toe. The cut is made in a V-shape near the distal metacarpal joint, which allows the entire toe to be moved laterally to the correct alignment. A small metal screw is fixed to the joint to provide stability while healing takes place.
The exostectomy and the osteotomy are performed during the same procedure. This is necessary because if one is carried out without the other, further toe deformity could result. After the surgery is complete, most patients can walk the next day, providing they wear shoes that provide the toe with the correct support. Activity should be limited, however, to ensure that the toe heals correctly.
A chevron osteotomy is just one type of procedure available for the treatment of bunions. Other types of surgery that might be used to correct a hallux valgus deformity include the Myerson/Ludloff procedure and the Lapidus procedure. Generally, one of these two is used in cases of very severe toe deformity. In these procedures, the cut in the metatarsal bone is made at the proximal end of the metatarsal, closer to the base of the toe. Cutting the bone at the proximal end allows the surgeon to correct a greater degree of toe-bending.
To determine whether a patient requires a chevron osteotomy for bunion removal, or whether another procedure is more appropriate, X-rays of the foot are taken and examined. There are two main factors that determine which type of osteotomy will be performed: the angle of normal alignment between the big toe and second toe, and the degree to which the big toe is abnormally bent. The chevron procedure is performed when the big toe has undergone a moderate degree of bending.