There is a growing application for percutaneous techniques in orthopedic foot and ankle surgery and a trend toward incorporation of minimally invasive procedures in practice today. Many minimally invasive procedures such as percutaneous bunionectomy and lesser toe corrective surgery have demonstrated sustained success and outcomes with minimal complications.¹,² While the literature pertaining to percutaneous Lapidus surgery is limited, the authors have found reliable and predictable outcomes in the appropriately indicated patient.

The Lapidus procedure was first reported in 1934 and is a versatile procedure used to treat a wide array of first ray deformities.³,⁴ The Lapidus procedure aims to treat pathologies including but not limited to tarsometatarsal (TMT) joint instability, hallux valgus deformity, flatfoot deformity, as well as TMT arthritis with the primary goal of surgery to obtain a fusion of the first TMT joint in appropriate alignment. The open Lapidus procedure has increased in popularity as surgeons have recognized the powerful ability to correct the multiple planes of hallux valgus deformity using this midfoot fusion.⁵ The percutaneous method to the Lapidus procedure was first introduced in Europe by Dr. Mariano do Prado in the 1990s and further substantiated by the international minimally invasive foot and ankle society, MIFAS by GRECMIP international society over the last two decades. In a recent study published by Vernois et al., the investigators followed and reviewed 75 feet treated with a percutaneous Lapidus procedure by a single surgeon.⁶ An Akin osteotomy was routinely performed, and the procedure was performed for a flatfoot correction in 10 of the cases. The satisfaction rate was found to be good or excellent in 95% of the cases with no complications involving metatarsalgia transfers or infections. While further long-term outcome studies are needed, the authors have found similarly encouraging outcomes and remain optimistic about the evolution of the percutaneous Lapidus using the described technique in treating first ray deformities minimally invasively moving forward.

Patients typically present with a painful bunion deformity that has failed prior nonsurgical treatment options and lifestyle modifications. Many will have already tried toe spacers, bunion splints, custom orthotics, and other various shoe wear alterations to accommodate the deformity and alleviate discomfort. The primary site of discomfort may be along the medial eminence, plantarly in line with the sesamoids, or more global pain across the entire first metatarsophalangeal (MTP) joint in cases of early-stage hallux rigidus. Family history usually demonstrates a lineage of bunion deformity.

On physical examination, the bunion deformity is obvious and easily visualized. But, it is important to perform a comprehensive lower extremity examination before all attention is drawn to the forefoot. Initial visual inspection of the gait, calcaneal alignment, ankle alignment, arch, and skin elucidate other associated pathologies. It is important to identify concomitant malalignment such as progressive collapsing flatfoot deformity or metatarsus adductus. Performing a Silverskiöld test to assess gastrocnemius and Achilles tightness helps to prevent forefoot overload or over plantarflexion of the first ray during surgical correction.
Mobility of the first TMT joint helps with presurgical planning and decision-making. Lastly, a thorough neurovascular examination should be documented.

The primary imaging study is plain radiography. Anteroposterior, oblique, and lateral radiographs of the foot allow for the evaluation of the deformity, position of the sesamoids relative of the first metatarsal head, as well as other associated deformity such as hallux interphalangeus or metatarsus adductus. Anteroposterior views allow for measurement of the hallux valgus angle and more importantly, the intermetatarsal angle. Lateral radiographs evaluate for first TMT joint instability, noted by plantar gapping or subluxation of the metatarsal cuneiform joints, as well as associated flatfoot deformity. Oblique radiographs visualize the lesser metatarsal shafts in finer detail, which may show evidence of cortical hypertrophy in cases of chronic overload due to abnormal force distribution attributable to the hallux valgus deformity.

There is a growing role for the utility of CT, especially weight-bearing CT scans in hallux valgus deformity. This allows for better visualization and quantification of the pronation deformity of the first metatarsal and the relative position of the sesamoids to the crista of the plantar first metatarsal head. CT may also reveal degenerative changes in the first MTP joint that dissuade the surgeon from choosing the Lapidus to correct the deformity. These studies are not vital for surgical planning and can be financially burdensome. There is no defined role for MRI in the evaluation of isolated hallux valgus deformity unless the presentation is atypical and the surgeon is seeking an alternative reason for pain.

Preoperative planning begins with the history and physical examination. The severity of the deformity, flexibility of the first TMT, and associated pathologies such as concomitant hammertoes or metatarsus adductus help to determine the surgical and postoperative plan. Radiographic assessment and planning are paramount. Measuring the intermetatarsal angle, hallux valgus angle, and metatarsal length creates an objective assessment of the amount of planned correction to use as reference.

Setup is unique to the surgeon’s handedness and the laterality of the operative extremity. The patient is positioned with the operative foot hanging off the end of the bed just proximal to the level of the malleoli. For a right-handed surgeon, the fluoroscopy will be on the right side of the patient regardless of the laterality of the operative extremity. For a left foot, the surgeon will stand on the left side of the operating room table, proximal to the foot while the assistant will stand at the foot of the bed. For a right foot, the surgeon will stand at the foot of the bed and the assistant on the right side of the bed. This positioning allows for unimpeded access to the foot during fluoroscopy, maneuverability of the handpiece, and it avoids the need to use the burr ambidextrously (Figure 5.1). Naturally, this setup is reversed for a left-handed surgeon.