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Avoiding the Pitfalls of the “Cheater Akin:” Best Uses of Phalangeal Osteotomies
Jeffrey A. Ross, DPM, MD lectured on phalangeal osteotomies for hallux valgus at the APMA National. Podiatry Today asked him a few questions about what he thinks podiatrists most need to know.
Q: Some colloquially label an Akin osteotomy as a “Cheater Akin” in the world of bunion surgery; do you feel this is truly the case?
A:
Dr. Ross reminds the audience that the Akin osteotomy is usually performed for correction of a hallux valgus deformity, in conjunction with a first metatarsal osteotomy, hallux interphalangeal deformity, and a long proximal phalanx. Specifically, the Akin procedure can correct an abnormal proximal articular set angle (PASA) by placing the osteotomy proximally on the phalanx. He adds that if one places the osteotomy distally, the surgeon can achieve correction of abnormal distal articular set angle (DASA).The surgeon may perform a derotational Akin to correct a valgus rotation of the great toe.
“When these criteria are met I would not regard this correction as a "cheater Akin," he says.
However, he adds that when the procedure is performed solely to aesthetically make the toe straighter, this moniker may apply.
Dr. Ross shares an example of a reoccurrence of a bunion deformity, that, upon further examination, is really the result of a hallux abductus deformity. The corrected first intermetatarsal angle remains normal. In this example, the toe deformity is pushing on the 2nd toe, causing recurrence of a previously corrected hammertoe, as well. He feels this is a case in which an Akin is truly applicable, because it is directed at a specific deformity for which it is intended and not simply a cosmetic or visual result.
“One should not perform an isolated Akin to correct for a bunion deformity, where there is a significant medial deviation of the first metatarsal (metatarsus primus adductus), with an increased intermetatarsal angle,” he explains. “When isolated, an Akin procedure in this circumstance would be regarded as a "cheater's Akin", particularly with a high intermetatarsal angle.”
Q: What role do you feel the phalangeal osteotomy has in first ray surgery?
A:
When there is a deformity of the proximal phalanx, either proximally, distally or in angulation, the Akin has its place in the surgeon's tool box, he says. Surgeons should determine where to perform the Akin procedure by identifying where the level of the deformity is located within the proximal phalanx, adds Dr. Ross, an Associate Professor of Surgery in the Division of Vascular Surgery and Endovascular Threapy at Baylor College of Medicine.
Q: What practice pearls about phalangeal osteotomies do you feel surgeons can incorporate into their practice today?
A:
One pearl he mentions is to try and maintain hinge integrity.
“Don't be over aggressive with the wedges by preventing breakthrough of the lateral cortex,” he relates. “By maintaining the lateral cortex, the osteotomy will heal that much faster and prevent complications. An oblique oriented osteotomy reduces the chance of hinge failure, as it was suggested by Boberg, et al.1 But, a perpendicular-oriented osteotomy to the long axis of the proximal phalanx achieves a greater degree of correction and more stable fixation.”
Dr. Ross also feels that drawing angles of the PASA and DASA preoperatively to determine location of the osteotomy, as well as the amount of wedge (correction) one wants to achieve can afford an improved stable surgical result. Templates can be beneficial, he says, as well.
“Fixation is a surgeon's prerogative,” he explains. “Choose the type of hardware (modality) that you are familiar with, and that will maintain fixation in 3 planes.”
Lastly, he shares that he insists that patients use prescription orthotic devices after hallux valgus/Akin procedure correction.
“Biomechanics forces such as pronation of the STJ, abduction of the forefoot, and valgus rotation of the hallux during gait contributed to the deformity and will result in recurrence of the bunion and drift of the hallux,” he says. “The device will help to correct triplane motion and prevent such recurrence.”
Reference
1. Boberg JS, Menn JJ, Brown WL. The distal Akin osteotomy: a new approach. J Foot Surg. 1991; 30(5):431-436.
