How To Address High Intermetatarsal Angles In Bunion Surgery

Author(s): 
Jeffrey E. McAlister, DPM, AACFAS and Christopher F. Hyer, DPM, MS, FACFAS

Given that high intermetatarsal angles can complicate hallux valgus correction, these authors discuss key preoperative considerations, highlight important aspects of corrective procedures and provide pearls on dealing with complications and postoperative protocols.

Hallux valgus is a common condition that foot and ankle surgeons treat and it affects a wide range of age groups. As hallux valgus can affect an adolescent athlete, a middle-aged female or an elderly patient with rheumatoid arthritis, the presentation of hallux valgus can vary. Additionally, there are varying degrees of severity with the deformity. More severe deformities may limit a patient’s daily activities and cause extreme discomfort through excessive inflammation and instability in and around the metatarsophalangeal joint (MPJ).1

   When we consider the severe bunion deformity and high intermetatarsal angles, we have to think beyond a simple “hallux valgus” correction. With severe deformity, often a significant widening of the first and second intermetatarsal angle is present. This can result from advanced arthrosis or instability of the first tarsometatarsal joint. In some cases, there is increased instability between the first and second cuneiforms as well, exacerbating the medial column hypermobility. Equinus contracture of the triceps surae may also be a contributing pathology and one needs to address this.

   Our surgical procedures are aided by specific radiographic parameters but the clinical evaluation plays an important role as well. When evaluating these patients, it is important to treat the causative factor in order to prevent under-correction or recurrence of the deformity. If one does not address the proximal apex of the deformity with either osteotomies or fusions, the deformity with or without pain will recur. The apex of many high angle hallux valgus deformities lies at the tarsometatarsal joint. Accordingly, correction often starts there.

   The original Lapidus procedure, described in 1934, aimed to address the metatarsus primus varus arising from first tarsometatarsal hypermobility.2 Therefore, it is important to thoroughly evaluate the patient clinically in order to determine the driving force of the deformity. One can address instability at the first tarsometatarsal joint and medial column with a primary arthrodesis and, if necessary, adjunctive procedures.3

Pertinent Pointers On The Preoperative Evaluation

After a thorough medical history and focused physical examination, one can determine the etiology of the patient’s hallux valgus. Adolescents with the juvenile bunion deformity have a genetic predisposition and often have significant hypermobility or ligamentous laxity. There is usually minimal pain associated with the bunion and patients do not become aware of the problem until their late teens. If they present at a younger age with a severe deformity and the growth plate is open, we try to wait until the growth plate closes in order to perform our definitive procedures. Adults often have more severe cases and concomitantly have a worse clinical presentation.

   In either situation, it is important to understand the whole picture. What is driving the patient’s deformity? Which joints are involved? Determine if it is just the MPJ, the tarsometatarsal joint or the intercuneiform articulation that are involved. Is there underlying inflammatory or degenerative arthritis? Is there pes plano valgus? Ascertaining these critical aspects of the overall foot structure will determine if one needs to perform additional procedures alongside a first tarsometatarsal arthrodesis.

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Great work Dr. McAlister! Hope you're doing well.

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