Blood Flow to the Metatarsal Head After Chevron Bunionectomy

Abstract

Background: Avascular necrosis (AVN) of the metatarsal head is a known, but infrequent, complication of a chevron bunionectomy. An increased incidence of AVN has been reported with the addition of an adductor tenotomy and lateral release. The purpose of this study was to document the vascular insult to the metatarsal head during a chevron bunionectomy with adductor tenotomy and lateral release through direct blood flow measurements during the procedure. Methods: A prospective study of 20 patients was performed. A chevron bunionectomy was performed under regional anesthesia without tourniquet control by two surgeons. Blood flow recordings were documented during key portions of the procedure: baseline, medial capsulotomy, adductor tenotomy and lateral release, and chevron osteotomy. The Periflux PF3 laser Doppler probe (Perimed, Inc., North Royalton, OH) was used to record blood flow. Mauchly's test of Sphericity and a pairwise comparison were performed with significance defined as p < 0.05. All patients had radiographs 3 months postoperatively to assess AVN. Results: There was a statistically significant decrease in blood flow to the metatarsal head at each portion of the procedure. The greatest insult occurred with the medial capsulotomy (45% decrease). The lateral release and adductor tenotomy caused a 13% decrease and the chevron osteotomy caused a 13% decrease, totaling 71% decrease from the baseline. There was no evidence of AVN at 3 months, and all patients had radiographic evidence of union without recurrence or over-correction. Conclusion: The addition of the adductor tenotomy with lateral release often is crucial to obtain the desired correction and avoid the complication of recurrence. The disruption of microvascular blood flow to the metatarsal head after a chevron bunionectomy with adductor tenotomy and lateral release was not complete, totaling 71% in the study population. The greatest insult occurred with the medial capsulotomy. There were no occurrences of AN. Despite the fear of AN, this study demonstrated that an adductor tenotomy and lateral release could be done safely completed with a chevron bunionectomy.