Fifth Metatarsal Chevron Osteotomy for Bunionette

Harold B. Kitaoka

Patients with bunionette (i.e., tailor’s bunion) have pain over the lateral forefoot, corresponding to the lateral condylar process of the fifth metatarsal. There may be associated bursitis, intractable plantar keratosis of the fifth metatarsal head, and difficulty tolerating most footwear (1, 2, 3, 4, 5, 6, 7, 8, 9 and 10). The main indication for fifth metatarsal osteotomy is for pain relief. Although there is usually varus malalignment of the fifth toe associated with the bunionette, the malalignment alone is not a consistent source of symptoms. A patient with a bunionette often has significantly increased fifth metatarsophalangeal (MTP) and intermetatarsal 4-5 angles (11). The fifth metatarsal may be bowed laterally or splayed or the metatarsal head enlarged. Nonoperative treatment includes footwear with a wider toe box and softer upper. Stretching the upper with a ring-and-ball device is helpful.

The distal chevron fifth metatarsal osteotomy has been successful for the treatment of hallux valgus (9), and a similar technique has been applied to the bunionette (5,7). It may be performed in patients with different types of bunionette deformities, including those with marked splaying (increased intermetatarsal 4-5 angle), lateral bowing of the metatarsal, and enlarged metatarsal head. Unlike the chevron first metatarsal osteotomy for hallux valgus, the operation may be successfully used even in patients who have more severe deformities, because there is no correlation between the degree of fifth metatarsal splaying and the clinical results (5). This operation may be successful in adults of all age groups. It is appropriate if there is satisfactory fifth MTP joint function. In some instances, this operation may be performed as a salvage procedure after failed lateral condylar process resection if most of the fifth metatarsal head remains.

INDICATIONS AND CONTRAINDICATIONS

Indications are a painful bunionette with difficulty with footwear. Contraindications of distal fifth chevron metatarsal osteotomy are the absence of pain and presence of stiffness and/or arthrosis of the fifth MTP joint. Another contraindication is skin ulceration or infection, which may occur in patients with bunionette and sensory neuropathy. Peripheral vascular disease is also a contraindication. When there are severe juxta-articular erosions associated with an inflammatory disease, osteotomy at the distal level may not be possible.

PREOPERATIVE PLANNING

It is important to carefully assess the patient’s symptoms and signs to determine whether operative treatment is indicated. It should be considered in patients who have failed nonoperative treatment such as use of footwear with a wider toe box, softer leather upper, and shoes in which the
leather is stretched over the lateral forefoot prominence. Based on the patient’s symptoms (e.g., pain, restricted activities, restricted footwear), medical evaluation, radiologic studies, and appropriate patient expectations, the decision regarding surgery can be made.

On physical examination, the alignment of the fifth toe should be assessed. Fifth MTP joint range of motion in the dorsiflexion-plantarflexion plane should be determined, as well as whether this motion is painful. The presence of intractable plantar keratosis beneath the fifth metatarsal head should be documented. The physician should also observe evidence of abnormal forefoot loading in other regions such as under the fourth metatarsal head and the presence of fat pad atrophy. The presence of other lesser toe or great toe deformities should be noted. Other associated fifth toe problems such as hammer toe with or without dorsal subluxation at the MTP level or corn formation at the interphalangeal level should be noted. A general medical examination is necessary to identify regional or general conditions that may be the source of problems such as peripheral vascular disease, diabetes mellitus, and systemic inflammatory diseases. Anteroposterior and lateral weightbearing radiographs of the standing patient and an oblique view of the foot should be obtained to assess the level of arthrosis at the MTP joint, juxta-articular erosions, and alignment with respect to intermetatarsal 4-5, and MTP-5 angles. Fifth MTP subluxation also should be assessed on the radiographs.

Although this chevron-type metatarsal osteotomy has application for most bunionette problems, including those with severe deformities, there are alternative procedures that may be useful in specific situations (1,3,4,6,8, 9 and 10,12

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