Inevitably with any osteotomy, the surgeon will experience some aspect of shortening typically one to two millimeters of shortening with each pass of the saw blade. As a result, meticulous surgical technique is imperative to minimize iatrogenic shortening. Additionally, different osteotomies inherently result in various amounts of shortening. The literature reports shortening as little as 2.0–2.5 mm following a Chevron bunionectomy and up to 3–7 mm of shortening in the Mitchell bunionectomy [3, 4]. Banks et al. documented 1.1–2.5 mm of shortening following closing base wedge bunionectomy [11]. Patients with a wider metatarsal will expect to get increase shortening with a closing base wedge bunionectomy. When comparing the angulation of the cut with respect to the long axis, the obliquity does not influence the amount of shortening [11]. Opening base wedge bunionectomy, on the other hand, theoretically may maintain metatarsal length. Budny et al. reported an increase in length following an opening base wedge bunionectomy of 0.47–1.35 mm depending on the size of the graft inserted from 2 to 6 mm [12].

Patients with an iatrogenic shortened first metatarsal can be asymptomatic; however, common symptoms often include transfer metatarsalgia especially with barefoot walking, elevated hallux with pain on range of motion of the first metatarsophalangeal joint, and the discomfort can be to a point which inhibits the patient from enjoying the same lifestyle and performing daily activities prior to surgery (Fig. 11.2a–c). In these cases, standard dorsoplantar and lateral radiographs should be obtained to compare to preoperative radiographs. In the instance that the surgeon does not have access to preoperative radiograph, utilization of contralateral films is used for comparison. Once the surgeon has identified the patient’s specific symptoms, they may address the causative agent both conservatively and surgically. Oral anti-inflammatory medications along with shoe modification and orthotic management may be implemented. A rigid sole shoe with a rocker bottom will off-load the forefoot during push off. Orthotic management with medial posting or the addition of a Morton’s extension may be utilized. If conservative treatment is unsuccessful or not compatible with the patient’s lifestyle, surgical management may be required. Prior to initiating surgery, a patient must be well informed that they may not return to all previous activities.

Surgical correction of a shortened first metatarsal can be performed utilizing a lengthening osteotomy, callus distraction, or functional lengthening with a first metatarsophalangeal joint arthrodesis. Single-stage lengthening with a bone graft or callus distraction can be implemented but correlates with higher rates of stiffness of the first metatarsophalangeal joint depending on the amount of lengthening required. It is recommended that single-stage procedures be performed when less than 15 mm of length is required [4, 5, 13, 14]. If subsecond metatarsal pain is the primary complaint, restoration of the metatarsal parabola with a second metatarsal shortening osteotomy can address the deformity.

Goldberg et al. described a step cut first metatarsal osteotomy, where a Scarf-type osteotomy is performed and translated distally and fixated. When performing this procedure, the Scarf type of osteotomy must be made with the long arm of the metatarsal parallel with the long axis of the bone and not parallel with the weight-bearing surface, to avoid elevation of the metatarsal head. Gudipati et al. documented early-onset arthritis of the first metatarsal phalangeal joint following Scarf lengthening osteotomy , which required arthrodesis within 2 years following the procedure [5, 15]. With lengthening procedures, one must not neglect the soft tissues; tissue advancements and extensor hallucis longus tendon lengthening may be necessary. Even after corrective procedures to address the short first metatarsal, patients still may require shoe modifications and other conservative managements. Singh and Dudkiewicz found following Scarf lengthening procedure that only 6 out of 16 patients had good pain relief following the procedure and 4 no longer required orthotic management . Following the study they concluded that patients with less than 10 mm of length had poor outcomes. Less than 50% success rate was noted with lengthening less than 8 mm [16].

Callus distraction is a viable option if a large amount of lengthening is required or there are significant soft tissue contractures or compromise. A single plane monorail external fixator can be placed along the medial border of the first metatarsal. Then a small longitudinal incision is made on the dorsal aspect of the first metatarsal, and a corticotomy is performed. A 7- to 14-day latency period is observed, and then distraction at a rate of 1 mm/day is performed until the desired length is achieved; the monorail is left in place an additional 2–4 weeks to allow consolidation. Although callus distraction can be utilized, commonly we encounter increased first metatarsophalangeal joint stiffness and symptoms following these lengthening techniques; therefore, it is the author’s preference to address shortening with functional lengthening via an end-to-end arthrodesis or interpositional bone block arthrodesis. We have found that, in most cases, enough length is available to achieve the desired correction with an arthrodesis. Once the fusion has consolidated, the functional length of the first metatarsal extends to the interphalangeal joint of the hallux.

When the deformity has been present for a prolonged amount of time, contractures, joint stiffness, or degenerative changes can be seen to the first metatarsophalangeal joint. At this point, an arthrodesis is the preferred method of treatment. Typically, we find that a primary end-to-end first metatarsophalangeal joint arthrodesis can be performed, thus increasing the functional lever arm of the first metatarsal to the interphalangeal joint. In instances with excessive shortening, interpositional bone block arthrodesis should be performed, which will be discussed later in this chapter. Primary first metatarsophalangeal joint arthrodesis is performed through a standard dorsal medial incision; limited medial and lateral dissection is required at this point. Once the extensor hallucis longus has been identified, sharp dissection is utilized to create a single soft tissue layer dissected off of the osseous structure. Any previously applied hardware should be removed, and periosteal elevator can by utilized to free plantar adhesions, to allow the surgeon to better access the joint. Preparation of the arthrodesis site can be performed with the use of curettage, reaming, or saw resection. It is the authors’ preference to utilize curettage or reaming to decrease shortening and increase ability to position the arthrodesis site in the appropriate position. Following resection, the articular cartilage of the head of the first metatarsal and base of the proximal phalanx the joint is irrigated to remove any cartilaginous or soft tissue debride within the joint. Subchondral drilling is performed with a 1.5 mm drill bit, and the autogenous cancellous graft from the drill bit is left within the arthrodesis site (Fig. 11.3). The ideal positional of the arthrodesis is variable throughout the literature and is patient dependent, with the most widely accepted angles being 10–15° of dorsiflexion, 10–15° of abduction, and neutral in the frontal plane. In the intraoperative setting, simulated weight bearing is performed by evenly loading the forefoot on a lid from a hardware tray and positioning the hallux parallel to a rectus second digit and slightly elevated on off of the platform (Fig. 11.4). A periosteal elevator can be utilized to elevate the hallux just off the weight-bearing surface to allow an appropriate amount of plantar clearance upon ambulation. Temporary fixation is applied from the proximal phalanx into the metatarsal and positioned out of the way of planned definitive fixation. Fluoroscopy is utilized intraoperatively to confirm satisfactory alignment of the hallux and arthrodesis site, and an interfragmentary 3.5 solid sore or cannulated screw is applied from the medial aspect of the metatarsal to the lateral aspect of the proximal phalanx utilizing lag technique. The ideal starting point for the screw is just proximal to the previously resected medial eminence (Fig. 11.5). After good interfragmentary compression is achieved, a low-profile dorsal plate is applied. Multiple hardware configurations from Kirschner wires, Steinmann pins, screw fixation, screw and plate fixation, plate fixation alone, multiple stacked plates, staples, external fixation, and combinations of the above have been described in the literature with similar fusion rates ranging from 87% to 100%, with most consensus of 95% fusion rate [10]. When evaluating the various configurations for fixation of the first metatarsophalangeal joint, an interfragmentary screw with dorsal plate was found to be the strongest construct by Politi et al. when they compared to crossed Kirschner wires, interfragmentary screws, and dorsal compression plate without interfragmentary screws. An interfragmentary screw with dorsal compression plate is our preferred construct especially in revisional surgery [17].

Avascular necrosis (AVN) is bone death secondary to impaired circulation and can be seen in any bone in the body. It can be the result of iatrogenic causes, traumatic injury, or systemic issues, such as metabolic disorders, hemoglobinopathies, tobacco abuse, alcohol abuse, and systemic or injectable corticosteroid use. AVN can be seen associated with or independent of a nonunion. The incidence in the literature varies from 0% to 76% depending on surgical technique and amount of periosteal stripping [3, 4]. The vascular supply to the first metatarsal is an intricate network of vessels that anastomose with one another along the entire course of the first metatarsal. Along with the nutrient artery, a periosteal capillary network and metaphyseal capital vessels contribute to the blood supply. These vessels all stem from the first dorsal metatarsal artery, first plantar metatarsal artery, and superficial branches of the medial plantar artery [6, 8, 18]. Every osteotomy can potentially cause AVN, as it is disrupting the blood supply, but distal metatarsal head osteotomies have a higher prevalence due to the location of the nutrient artery of the first metatarsal, which enters through the dorsolateral aspect of the distal two thirds of the first metatarsal. The nutrient artery of the first metatarsal branches into a proximal and distal segment. It then anastomoses with the metaphyseal capital vessels at the junction of the head and neck of the first metatarsal. The capital fragment also has periosteal vessels attaching around the attachment of the capsule, and capsular vessels penetrate the head segmentally [4, 7, 8, 18, 19].

During early investigation, authors recommended limiting the lateral release during a distal first metatarsal osteotomy, as it was thought to be the only remaining blood supply to the capital fragment. Recent anatomic studies contradict the previous allegations and states that lateral release can be performed without causing significant vascular insult. Kuhn and Lippert performed a study where intraoperative intraosseous blood flow was measured after medial capsulotomy, adductor tenotomy, lateral release, and Chevron osteotomy. There was significant difference in blood flow at each portion of the procedure; the most notable insult was after medial capsulotomy with average decrease of 45% of baseline, lateral release another 13% decrease (58% total), and osteotomy another 13%. Even with this documented amount of vascular insult, all 20 patients healed without complication postoperatively [18]. There is no doubt that the blood supply to the first metatarsal is disrupted; the real questions are as follows: Is the vascular insult permanent or can it be reversed? And if this is the case, what are the different factors that make a patient more susceptible to this complication?

Since the intraosseous blood supply is compromised during a metatarsal osteotomy, special care should be taken in all aspects of the surgical procedure in order to limit the potential of AVN. The metatarsal has a significant capacity to withstand and compensate for the vascular insult, but limited capsular and periosteal stripping to preserve extraosseous and capsular vascular supply should be implemented. Care should be made to not allow the saw blade to plunge through the lateral cortex into the intermetatarsal space when performing the osteotomy. When dissecting the medial capsule, limiting trauma and cauterization of the plantar vasculature is important. It has been previously reported that when performing the osteotomy thermal necrosis to the bone can be seen if temperatures of 50°C maintained for 1 min or longer. The addition of saline irrigation to the saw bone interface has been suggested to limit temperatures. Hall et al. reviewed 112 first metatarsal osteotomies in cadaver bones and found that the addition of saline irrigation while the osteotomy was being performed resulted in a mean decrease in cutting temperature of 2.96 ± 7.32°C. However, temperatures with or without saline did not approach a level that would be consistent with thermal damage. The greatest change from base temperatures in the study was 43.7°C. The average peak temperature demonstrated in the study was 30.47° [19, 20]. As a result, we feel that it is really surgeon’s preference as to whether one should use saline while performing the osteotomy.

Avascular necrosis to the capital fragment of the first metatarsal can be minor without collapse or major with collapse following a bunionectomy . The patient’s clinical presentation may vary. Diagnosis in the early postoperative period is difficult, as the symptoms resemble those similar to postoperative healing process, with edema, erythema, irritability, and increased tenderness surrounding the joint. This reaction is a result of the body attempting to repair the devascularized bone. As with clinical diagnosis, radiographic evaluation in the immediate postoperative period is also difficult. In the early stages of AVN, the metatarsal may demonstrate subchondral radiolucency and focal cystic changes and may appear mottled; these radiographic changes can be seen on average within the first 2 months of surgery (Fig. 11.6). As the pathology progresses, degeneration of the capital fragment, subchondral collapse, and joint space narrowing is noted (Fig. 11.7). Magnetic resonance imaging (MRI) is the most sensitive modality with a 90–100% sensitivity for diagnosing AVN. Due to this sensitivity, the MRI can have high false-positive findings in the early postoperative period. Common appearance on MRI consists of decreased signal intensity on T1-weighted images, secondary to decreased cancellous bone content and increased T2 signal intensity due to hyperemia and edema. The double-line sign on a T2-weighted image is diagnostic and is seen on the periphery of the boney infarct. This consists of a line of increased signal intensity surrounded by an outer line of decreased signal intensity (Fig. 11.8a, b). Osteochondral fragmentation and degenerative changes are also noted in the later stages. Technetium-99m bone scintigraphy can be used in the postoperative period but is only 85% sensitive and is nonspecific. Scintigraphy will demonstrate changes in response to the initial osteotomy, so it is recommended that the surgeon wait a minimum of 4 weeks prior to imaging in order to be able to better differentiate between the initial vascular insult and AVN [6, 8, 19]. Wallace et al. performed a review of 13,952 patients who underwent first metatarsal head osteotomies, and 15 (0.11%) developed avascular necrosis. Thirteen out of fifteen (87%) had Chevron bunionectomy; two (13%) had Scarf procedure. On average, AVN was documented 4 months postoperatively. There was no increased incidence noted with respect to fixation type. All 15 patients responded to conservative treatment consisting of non-weight bearing in a cast and nonsteroidal anti-inflammatory medication [8].

Conservative treatment should start with off-loading and limiting the stresses on the first metatarsal phalangeal joint with orthotic management or shoe modifications. Partial or complete non-weight bearing may be beneficial in the initial stages. The majority of patients respond to conservative treatment, but those that do not may require surgical intervention. If the osseous integrity is still preserved and collapse of the capital fragment has not resulted secondary to the AVN, the patient’s symptoms may resolve with synovectomy and subchondral drilling . Moderate to severe cases will require first metatarsophalangeal joint arthrodesis with or without interpositional grafting [19]. When determining if the use of interpositional graft is necessary, the overall bone stock, viability, and length of the first metatarsal need to be taken into account. If after resection greater than 1 cm of bone loss is noted or cosmetic appearance of the shortened first ray is not favorable, an interpositional graft should be utilized. With an end-to-end first metatarsophalangeal joint arthrodesis, the overall functional length of the metatarsal is extended to the level of the interphalangeal joint.