Abstract
The Cotton osteotomy is a mainstay procedure in the foot and ankle surgeon’s repertoire during correction of progressive collapsing foot deformity (PCFD). The procedure involves a dorsal opening wedge osteotomy of the medial cuneiform followed by insertion of a bone wedge for recreation of the medial longitudinal arch. This addresses the forefoot varus component of a flatfoot, and is typically used in conjunction with other procedures to achieve correction in all planes. The osteotomy provides a supinatory moment around the triple joint complex. However, some pitfalls have been reported which have negative impact on reproducibility. These include lateral column overloading due to over-correction, sesamoid pain due to under-correction, breach of the plantar hinge, and even joint violation. Due to intricate local anatomy, proper identification of the location and trajectory of osteotomy placement is vital to ensuring avoidance of injury to adjacent joints. The purpose of this paper is to report on a simple technique utilizing a Kirschner wire guide pin for osteotomy guidance, resulting in improved patient outcomes and reproducibility.
Level of evidence
Level V
Introduction/Discussion
Cotton first described the dorsal opening wedge medial cuneiform osteotomy in 1936. He designed the procedure to plantarly displace the first metatarsal head in order to restore the “triangle of support” between the first metatarsal head, fifth metatarsal head, and the calcaneus. ( Figs. 1A , 1B ). This procedure can help correct forefoot varus and recreate the medial longitudinal arch in lieu of medial column fusion. The Cotton procedure has been widely utilized as an adjunct in the correction of pediatric pes planovalgus deformities, adult acquired flatfoot deformities, and in the correction of residual forefoot varus following triple arthrodesis. ,
Dorsal to plantar positioning of the guidpin in the medial cuneiform.
The Cotton osteotomy is a dorsal opening wedge osteotomy of the medial cuneiform that plantarflexes the first metatarsal.
The dorsal to plantar dimension of the medial cuneiform is about 30 mm. It has a cross-sectional triangular or pear shape, with an inferior base and a superior apex. It is kidney-shaped in the coronal plane, with a concave lateral border and convex medial border. It is important to make the Cotton osteotomy perpendicular to the long axis of the bone in the mid portion of the cuneiform. The first tarsometatarsal (TMT) joint is angled distal-dorsal to plantar- proximal at an 18 to 25 degree angle. The surprising depth and odd shape of the medial cuneiform as well as the angled adjacent joints can make it difficult to place the osteotomy in the correct location. An osteotomy placed too distally or angled to distally may enter and disrupt the first TMT joint. An osteotomy placed too proximally or angled too proximally may enter and disrupt the medial naviculocuneiform (NC) joint. An osteotomy placed too laterally can enter the middle cuneiform or second TMT joint.
Yarmel et al described a technique of finding the first TMT joint distally and naviculocuneiform (NC) joint proximally with small-gauge needles under fluoroscopy. They then used the second TMT joint as a landmark and performed the osteotomy 2-4 mm. proximal to the second TMT joint. Aiyer et al described the use of a guide pin to identify the center of the medial cuneiform but the exact technique was not described. We describe a simple technique to safely perform a Cotton osteotomy utilizing a guide pin to identify the proper location and trajectory of the osteotomy in order to avoid injury to adjacent joints.
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