The foot and ankle surgeon today cannot consider any fusion procedure without a high index of suspicion for metabolic bone disorders or in the management and cessation of smoking. The effects of nicotine on bone healing have been well established, and in recent years greater attention has been placed on vitamin D deficiency , thyroid problems, and the effect of medications on bone healing. Correction of these disorders prior to performing the index Lapidus procedure is critical to avoid some of the complications that will be discussed in this chapter.

Although there is regional variation in the performance of the Lapidus arthrodesis, there are some universal technique pearls that can help to minimize complications and pitfalls in performing the procedure. Placement of the incision more dorsal medial can help to avoid nerve entrapment and can increase visualization of the entire dorsal to plantar dimensions of the joint (Fig. 15.9). This can help in resection of bone along the long axis of the metatarsal so as not to elevate the first metatarsal by not resecting enough bone from the plantar aspect of the joint. Adequate joint exposure and mobility are extremely important to be able to reduce the deformity in all three planes, and utilization of a small osteotome to free the plantar ligament structures can assist in obtaining this exposure and mobility of the bony segments for reduction.

Bony resection needs to be perpendicular to the long axis of the first metatarsal and the cuneiform to avoid excessive shortening and elevation of the first metatarsal, which are frequent complications reported with this procedure [20, 27]. In addition, nonunion of the Lapidus can occur because of poor joint preparation. Often, there is sclerosis of the subchondral plate, and poor preparation of the fusion site can be a major factor in the development of a nonunion. Resection of this sclerotic subchondral plate is key in helping to prevent nonunion of the fusion site [19, 20] (Figs. 15.10 and 15.11). Curettage techniques for joint preparation are still popular, but the author prefers bony resection in most cases to ensure good bleeding surfaces instead of the risk that a sclerotic subchondral plate has been “fish scaled” or fenestrated with lack of adequate blood supply for bony union. Some have argued that by leaving the subchondral plate intact, it provides more stability at the fusion site. This may be true with the crossed screw technique, but with recent advancements in plate fixation constructs, stability is excellent without preservation of the subchondral plate.

Correction of the intermetatarsal angle is usually accomplished by removing more bone on the lateral aspect of the articular surface of the cuneiform (Fig. 15.12). When there is difficulty with reduction of the IM angle, one easy technique is to resect a small portion of bone off of the lateral flare of the first metatarsal base to help “morits” the arthrodesis site (Fig. 15.13).

There are a couple of key points regarding alignment of the fusion site to consider. Certainly reduction of the intermetatarsal angle is the primary consideration, but rotation and translation of the metatarsal head are equally important and often overlooked. Using a small K-wire as a “joystick” can help in relocation of the sesamoids underneath the first metatarsal head by rotating the metatarsal out of valgus malalignment [21, 22] (Fig. 15.14). In addition, the entire metatarsal segment can be translated in a plantar direction a few millimeters to make up for some shortening of the metatarsal during the cartilage resection. Small K-wires can be used on either side of the first metatarsal base to temporarily stabilize the fusion and to check under fluoroscopy prior to final fixation (Fig. 15.14).

Traditional stacked screw fixation is still widely utilized, but interfragmentary screw and plate fixation has gained popularity in recent years [23, 24]. Delivery of one interfragmentary screw and plate supplementation on the plantar medial aspect of the fusion is an extremely stable construct and allows for early loading of the extremity [25, 26] (Fig. 15.15). The anterior tibial tendon attachment is extremely broad in this area, and the plate can be put just under the attachment by elevating a small flap and in some cases directly over the tendon attachment without compromise to the tendon.

Nonunion is the most frequent complication reported in the performance of a Lapidus arthrodesis [4–7, 27]. The nonunion rate has been estimated to be between 5.3 and 12% [4–7, 27]. As was previously outlined, this particular complication has a number of etiological factors that can contribute to its occurrence. Correction of any metabolic causes prior to surgery is recommended. There are several considerations in the management of a nonunion of the Lapidus procedure. Determination of the type of nonunion is extremely important. Certain characteristics surrounding the nonunion have to be considered as well.

Typically, there will be a specific pattern of swelling around the midfoot that generally is persistent with increased weight bearing. Pain is consistent on a daily basis with any loading activities and can be described as constant, throbbing, and aching. Plain radiographs will show loose or broken hardware most of the time, and an area of radiolucency will be seen with some ectopic bone formation surrounding the fusion site. In the presence of a hypovascular nonunion, there will be a space between the bony segments indicating a poor biologic response for healing.

Advanced imaging is helpful to identify the type of nonunion and the quality of the bone. The circumstances will dictate which imaging study is the best for that particular situation. The author has found that utilization of a CT scan tends to be the best study for most situations. Certainly if there are concerns about the quality of the surrounding tissues or the potential for an infected nonunion, then there are more appropriate studies to help in preoperative planning in those situations followed by a bone biopsy if indicated.

The majority of nonunions at this location are primarily hypervascular. This can generally be determined with plane radiographs. As previously mentioned, advanced imaging such as a CT scan , SPECT CT, or MRI can help in diagnosis and planning [28–30]. When deformity is not present, then the goal of the revisional surgery is to improve the biological response at the nonunion site. This typically involves removing the previous fixation and preserving as much viable tissue around the bone to preserve vascularity and then removing the fibrous elements within the nonunion to replace this interface with healthy bone graft and matrix to mount a biologic response toward solid bony fusion (Figs. 15.16, 15.17, and 15.18). All too often, surgeons dissect periarticular tissues to “mobilize” the corresponding bony structures that results in further devascularization of the area compromising the ability of the soft tissue to aid in a successful fusion. Typically, osteoconduction, osteoinduction, and in certain circumstances osteogenesis are necessary to aid in this biologic response. In elderly patients or immunocompromised patients, osteogenesis becomes a critical component in fusion success, and the use of mesenchymal stem cells may be considered. The osteoinductive and conductive properties in a cancellous bone graft is usually enough to obtain success in most cases. Both allograft and autograft have been recommended with success [31–34]. The author prefers autograft in these revisional situations because it provides all three properties previously outlined osteoconduction, osteoinduction, and osteogenesis. The most popular donor sites are the calcaneus or tibia. Both of these sites have a low complication profile and provide the necessary volume needed in revisional situations involving the Lapidus procedure.