8 Chevron Osteotomy for Hallux Valgus Correction Abstract The Chevron osteotomy is a reliable procedure for correction of mild to moderate hallux valgus. As with all hallux valgus correction, the Chevron osteotomy with or without distal soft-tissue realignment remains challenging, even for the most experienced foot surgeons. With careful clinical and radiographic evaluation, however, the Chevron osteotomy maintains its role as a dependable tool for correcting these deformities. Keywords: hallux valgus, bunion, metatarsus primus varus • Mild, moderate, or severe hallux valgus that have failed conservative care. Note: while absolute measurements of hallux valgus angles remain important in preventing recurrence and choosing the proper procedure for correction, it is a combination of these numbers with the clinical scenario that drives decision making. • Intermetatarsal angle (IMA) < 14 degrees. • Tenderness over the medial eminence of the first metatarsophalangeal (MTP) joint. • Deformity should be passively correctable. • Patients should have pain with weight-bearing activity and/or shoe wear. • May present with or without significant ankle, midfoot, or hindfoot deformity. • May have some decreased sagittal arc of motion at MTP joint. • Plain standing, weight-bearing X-rays of the foot looking for MTP joint congruence. Measurement of IMA between first and second metatarsal (MT) shafts; Mann’s classification is as follows: Mild: IMA < 13 degrees, HVA < 30 degrees. Moderate: IMA > 13 degrees, HVA < 40 degrees. Severe: IMA > 20 degrees, HVA > 40 degrees. Presence of hallux valgus interphalangeus. Increased distal metatarsal articular angle (DMAA). Lateral sesamoid subluxation. Arthritic change at the MTP joint. Prior bony procedures or fractures which may affect corrective planning. • Magnetic resonance imaging (MRI): Generally not indicated in this setting. Can be used if concerned about arthritic changes or an osteochondral defect in the MT head not seen on radiographs. Indicated when pain in joint with range of motion or axial grinding is worse than would be suggested on radiographs. • Computed tomography (CT) scan: Rarely used. Allows one to assess bone stock when cysts or osteochondral lesions can be seen with plain radiography. • Wide toe-box shoes with minimal stitching over region of medial eminence. • Bunion spacers or silicone pads. • Cutting hole in shoe over area of medial eminence. • Impaired vascular status. • Short first MT may predispose to transfer metatarsalgia post-operatively in the presence of a long second MT. • Skeletal immaturity. • Arthrosis at the MTP joint. • An incongruent MTP joint with an IMA of >14 degrees is thought to be a relative contraindication. • Translation of the first MT head laterally to correct the IMA to ≤ 9 degrees. • Stable osteotomy with reduction of the MT head over the sesamoids. • Stable, pain-free MTP joint correction with adequate great toe mobility for shoe wear. • Modest surgical time. • Stable osteotomy requires limited internal fixation. • Less surgical dissection than other techniques. • Allows one to assess and address intra-articular pathology and soft-tissue releases as well as bony correction through single incision. • Adequate bony translation of the first MTP head fragment should correct the deformity (Fig. 8.1, Fig. 8.2). • Careful soft-tissue balancing may fine-tune a bony correction and ensure a stable joint.
8.1 Indications
8.1.1 Clinical Evaluation
8.1.2 Radiographic Evaluation
8.1.3 Nonoperative Options
8.2 Contraindications
8.3 Goals of the Surgical Procedure
8.4 Advantages of Surgical Procedure
8.5 Key Principles