Zigzag tenotomy of the extensor hallucis longus through minimally invasive surgery in cadaveric specimens: description of a new technique.

Background: Lengthening of the extensor hallucis longus (EHL) is performed to address various forefoot pathologies. The retraction of this tendon is strongly associated with the Hallux Abductus Valgus (HAV) deformity. Minimally Invasive Surgery (MIS) lengthening of the EHL is carried out in combination with other surgical techniques for HAV bone realignment. It is performed without ischemia, using local anesthesia and sedation if required by the patient. One of the advantages of this technique is immediate ambulation with a postoperative shoe without the need for a cast. The objective of the research was to demonstrate the efficacy and safety of the minimally invasive technique for lengthening the tendon in patients with HAV.

Materials and methods: The procedures were performed on 11 fresh cryopreserved cadaveric feet. HAV surgery was performed through dorsomedial and dorsolateral portals for Reverdin-Isham, Akin and adductor tenotomy. In addition, EHL tendon elongation was performed using the Beaver 67 MIS scalpel through an incomplete zigzag tenotomy. The specimens used did not present any type of disease nor had they undergone previous surgeries that could affect the technique. First, the plantar flexion of the metatarsophalangeal joint was measured with a goniometer to establish the degrees of this joint before proceeding with the technique, the tenotomy was performed and remeasured and finally the osteotomy was performed. In addition, an anatomical dissection of cadaveric specimens was performed and various anatomical and surgical relationships were analyzed and measured.

Results: The data indicate that, after performing zigzag tenotomy, there is an average improvement of 13.91 degrees in plantar flexion.

Conclusions: The study confirms the effectiveness and safety of elongating the extensor hallucis longus tendon of the hallux using minimally invasive surgery. The zigzag technique for tendon elongation may be considered a viable minimally invasive treatment option for addressing tendon hyperextension in patients with HAV.