12 Akin’s and Moberg’s Osteotomies of the Hallux Phalanx Abstract Proximal phalangeal osteotomies of the hallux serve to correct alignment when combined with hallux valgus corrective procedures or are used to alleviate hallux rigidus symptoms in combination with cheilectomy or in isolation. Multiple techniques have been described, and successful techniques are highlighted in this chapter. Careful correction avoids complication of tendon injury, overcorrection, or loss of fixation. Keywords: Akin, Moberg, proximal phalanx osteotomy, hallux rigidus, hallux valgus • Hallux valgus interphalangeus. • Congruent hallux valgus treated with double osteotomy (Akin’s and metatarsal osteotomy). • Residual hallux valgus after correction. Hallux valgus is a malalignment of the first ray with prominence over the medial eminence and resulting pain. The deformity also creates impingement in the first web space. Deformity can be congenital or acquired with age. While exact etiology is unclear, family history plays a role. After diagnosing hallux valgus, one must rule out concurrent hallux rigidus. This diagnosis can require fusion of the great toe. Stability at the first tarsometatarsal (TMT) joint must be determined based on examination and radiographic studies. Instability requires a Lapidus fusion. Thereafter, the severity and congruence of the hallux valgus deformity must be determined. Akin’s osteotomy can be used as part of a double osteotomy in congruent bunions or in conjunction with other hallux valgus corrections to augment the correction. A weight-bearing foot radiograph series including anteroposterior (AP), 30-degree oblique, and lateral views is indicated. One can evaluate arthritis of the metatarsophalangeal (MTP) joint, instability at the TMT joint, MTP congruency, hallux valgus angle, and hallux valgus interphalangeus angle (Fig. 12.1). Magnetic resonance imaging (MRI) and computed tomography (CT) are not indicated for treatment of isolated hallux valgus. Hallux valgus can be treated nonoperatively with attempts at relieving pressure in shoes or relieving pressure on the adjacent second toe. Wider shoes can be tried and stretching of the toe box with a shoe-tree may help. Protection of the great toe irritating the second toe with a silicone spacer may relieve pain. Lasting deformity correction without surgery is not possible. • Performing an Akin osteotomy in isolation for incongruent hallux valgus. Akin’s osteotomy is used for deformity correction and relieving impingement of the great toe in the first web space. Success can be defined by a congruent MTP joint with a healed proximal phalanx osteotomy and no symptomatic hardware. A proximal phalanx osteotomy is a useful adjunct to hallux valgus deformity correction. Instead of relying on a soft-tissue correction to maintain great toe position, one can dial in the correction with a bony correction of the proximal phalanx. This results in less long-term deformity recurrence and, after adequate bony consolidation, allows for more aggressive range of motion (ROM) in the great toe. • Protect extensor and flexor tendons while limiting soft-tissue dissection. • Take care not to overcorrect this powerful osteotomy by checking iterations of a unicortical osteotomy. • Ensure secure fixation with no prominent hardware. As most Akin’s osteotomies are performed with a complete hallux valgus correction, position the patient at the edge of the operating table with slight external rotation. Calf tourniquet can be applied as needed. A longitudinal incision is made over the medial base of the proximal phalanx protecting the dorsomedial and plantar-medial nerve distributions. With concurrent bunion correction, continuation of the medial incision should be performed. Full-thickness dissection is made down to the medial aspect of the proximal phalanx. A Hohmann retractor is used to protect the extensor and flexor tendons. A guidewire is used to template the unicortical osteotomy. Transverse and oblique osteotomies have been described. An oblique osteotomy distal-medial to proximal-lateral will allow for normal compression with screw fixation. After satisfactory osteotomy position is determined under fluoroscopy, a microsagittal saw is used to perform the unicortical osteotomy, allowing compression of the medial cortex. Further correction can be obtained by compressing the medial osteotomy edges and using the kerf of the saw blade along the medial cortex. This ensures less overcorrection. After satisfactory alignment and correction have been achieved, the correction can be maintained with hardware placement. Permanent suture,1 staple, plate, and screw fixation have been described (Fig. 12.2). Transverse osteotomies may be better treated with plate or staple methods. Staple fixation has also been shown to be a viable option for fixation, with 5.9% of patients reporting tenderness over hardware.2 An oblique osteotomy, a solitary 2.4or 3.0-mm screw perpendicularly to the osteotomy, provides enough stability and compression (Fig. 12.3). For screw placement, template with guidewire starting at the medial base of the proximal phalanx. Some dissection of the capsule will need to be performed. The guidewire should be bicortical. The trajectory tends to be more dorsally driven than expected. Check placement on AP and lateral fluoroscopic imaging. A headless screw or countersink should be used prior to screw placement. This limits hardware prominence. One should check for compression of the medial cortex after screw placement.
12.1 Akin’s Osteotomy
12.1.1 Indications
Pathology
Clinical Evaluation
Radiographic Evaluation
Nonoperative Options
Contraindications
12.1.2 Goals of Surgical Procedure
12.1.3 Advantages of Surgical Procedure
12.1.4 Key Principles
12.1.5 Preoperative Preparation and Patient Positioning
12.1.6 Operative Technique
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