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One Surgeon’s Experience With the Cuboid “Zoom” Osteotomy
Foot and ankle surgery has progressed tremendously over the last several decades. With an emphasis on advancing technology and biomechanics, flatfoot correction has also improved. Appreciating the planal dominance theory in selecting the proper procedure is paramount to providing the best clinical outcome. This article presents the senior author’s decades-long implementation of the cuboid “zoom” osteotomy as an alternative to the traditional Evans osteotomy, with which he has found predictable success and reproducibility.
Evans first described his calcaneal osteotomy in 1975.1 This popular osteotomy aims to surgically address a flexible pes plano valgus deformity via transverse plane correction.2 The lateral column lengthening can correct the deformity in multiple planes without surgically addressing the medial column. The abduction of the forefoot, accompanied by midtarsal joint stability, supinates the subtalar joint and reduces the valgus frontal plane deformity.3
Dollard and colleagues described 5 major systems that have a dramatic effect on the integrity of the longitudinal arch: the midtarsal locking mechanism; compression joint tracking; the windlass mechanism; the plantar aponeurotic fascial bands; and medial column structural deficits.4 Restoring length to a short lateral column may improve the function of these systems. In the senior author’s experience, an opening cuboid “zoom” osteotomy can produce the same triplanar effect as seen with the Evans procedure with less required surgical demand.
Key Components of the Surgical Technique
The patient undergoes a preoperatve popliteal nerve block before placement on the operating room table in the supine position with an ipsilateral hip bump placed to facilitate access to the lateral foot. A tourniquet provides hemostasis. The surgeon then identifies the proximal and distal boundaries of the cuboid bone on fluoroscopy using an 18-gauge needle. A 6-cm linear incision over the cuboid extends from the sinus tarsi to the distal cuboid. One should place the incision dorsal enough so as to protect the peroneal tendons, yet using caution to avoid the dorsal intermediate cutaneous nerve. Sharp and blunt dissection techniques protect neurovascular structures and peroneal tendons, if encountered. The surgeon then splits the extensor digitorum brevis muscle longitudinally to expose the underlying cuboid bone. Fluoroscopy can confirm positioning and facilitate the identification of the center of the cuboid to determine the optimal location for the osteotomy. Then, one uses a sagittal saw to make a coronal osteotomy at the midline of the cuboid, taking care to leave the medial cortex of the cuboid intact.
A bone distractor placed across the osteotomy allows for the placement of the bone graft (click here for photo). The surgeon then inserts an 8-10 mm bone wedge allograft with the apex medial and base lateral into the osteotomy site until it is flush with the lateral wall (click here for photo). The osteotomy can be fixated with a Kirschner wire, staple, or buttress plate. A rasp or rotary burr can smooth the edges of the graft. Prior to closure, the surgeon confirms final position and hardware via fluoroscopy. The extensor digitorum brevis muscle repair takes place using 3-0 Vicryl suture, as does deep closure. Skin closure is achieved using 3-0 polypropylene suture.
The senior author places patients into a below-knee posterior plaster splint for 1 week after this procedure. Splint removal occurs at the first postoperative visit, replaced with a below-knee fiberglass cast which remains in place for 3 weeks. Cast and suture removal is at 4 weeks post-procedure, and the patient begins weight-bearing in a removable walking boot for the next 4 weeks. At this time, the patient begins active range of motion exercises and scar therapy. Physical therapy begins 8 weeks postoperatively, as does transition into an athletic shoe. The patient is allowed to resume normal activities 3 months postoperatively, including athletics.
What Role Could This Alternative Procedure Play?
The described opening cuboid osteotomy, in the senior author’s experience, offers comparable triplane correction to the traditional Evans osteotomy. Due to the cuboid’s rectangular shape, the surgeon can easily place the osteotomy by finding the midpoint of the cuboid. There are some advantages to utilizing an opening wedge in the cuboid compared to the Evans osteotomy. Making a central osteotomy that distributes pressure evenly to the calcaneocuboid joint and the cuboid-metatarsal joints diminishes the advanced arthrosis seen in the calcaneocuboid joint after the Evans procedure.5 Through our clinical and radiographic results, we feel this procedure restores the length of the lateral column and aids in increasing supination of the subtalar joint.
Many complications associated with the traditional Evans procedure are due to the unusual shape of the calcaneus.8 A cuboid osteotomy may avoid this challenge. Dorsal displacement of the anterior calcaneal tuberosity is commonly described with an incidence ranging from 11.8% to 100%.6 After creating a destabilizing osteotomy in the distal calcaneus, the insertion of a corrective wedge at this level may create a recoil effect with dorsal subluxation of the anterior segment. Adams and team reported even with fixation across the graft site, the incidence of subluxation does not improve.7
Anatomic studies reveal that one will encounter the sural nerve and peroneus brevis tendon ranging 5–15 mm proximal from the calcaneocuboid joint. Thomas and colleagues reported sural nerve injury in up to 11% of patients who underwent the Evans procedure.6 A multitude of studies attempted to identify the ideal location and angle with which to perform an Evans osteotomy. Bussewitz and coworkers performed a cadaveric study analyzing risk of subtalar joint articular facet injury with the Evans cut 1.3 cm posterior and parallel to the calcaneocuboid joint.9 Their results showed 40% sustentaculum tali involvement.9 Violation of the sustentaculum tali can have major consequences to the integrity of the medial longitudinal arch, the position of the rearfoot, and the adjacent structures, including the flexor hallucis longus tendon and the medial neurovascular bundle. Lastly, with the Evans procedure, the bone wedges can seat deep in the cancellous bone, leading to resorption and loss of calcaneal length.8
A cuboid “zoom” osteotomy is more distal along the lateral column where the peroneus brevis tendon and sural nerve continue to course plantarly, and is therefore in a likely safer anatomic position for an osteotomy. Another advantage of the cuboid is the combined vascular status and structural integrity. One may logically presume that correction maintenance is more likely over time with sufficient cancellous bone to aid with graft incorporation and a more structurally stable cortical bone during remodeling. The surgeon can easily apply fixation with a compressive staple across the allograft and into the lateral wall of the cuboid.
As with any surgery, risk factors do exist. We find that disruption of the peroneal groove may alter the pulley effect of the peroneus longus tendon as it courses to the base of the first metatarsal. Peroneal tendon irritation, tenosynovitis, rupture, or dysfunction could be long-term sequelae if the mechanics become altered, in our observation. Other risks that must be considered include hardware complications, delayed or malunion of the graft, increased adjacent joint pressure, and lateral column pain. Our experience has only revealed 3 cases (6%) with complications: one wound dehiscence, one neuritis, and one deep vein thrombosis.
Final Thoughts
Based on an attainable surgical technique and an attractive risk-benefit evaluation, the authors believe that, in their experience, the cuboid “zoom” osteotomy is a safe, effective and reproducible procedure option to treat flexible flatfoot deformity.
Dr. Mendeszoon is a fellowship-trained foot and ankle surgeon, a Fellow of the American College of Foot and Ankle Surgeons and the American College of Podiatric Medicine. He is the Director of the Advanced Foot and Ankle Fellowship with University Hospitals Richmond Medical Center in Richmond Heights, OH. He practices in Chardon, OH.
Dr. Iosue is a fellowship-trained foot and ankle surgeon, an Associate of the American College of Foot and Ankle Surgeons and a Fellow of the American College of Podiatric Medicine. She practices in Mentor, OH.
References
1. Evans, D. Calcaneo-valgus deformity. J Bone Joint Surg. 1975;57-B:270–278.
2. Phillips GE. A review of the elongation of os calcis for flat feet. J Bone Joint Surg. 1983;65: 15-18.
3. Dogan A, Albayrak M, Akman YE, Zorer G. The results of calcaneal lengthening osteotomy for the treatment of flexible pes planovalgus and evaluation of alignment of the foot. Acta Orthop Traumatol Turc. 2006;40(5):356–366.
4. Dollard MD, Marcinko DE, Lazerson A, Elleby DH. The Evans calcaneal osteotomy for correction of flexible flatfoot syndrome. J Foot Surg. 1984;23(4):291–301.
5. Cooper PS, Nowak MD, Shaer J. Calcaneocuboid joint pressures with lateral column lengthening (Evans) procedure. Foot Ankle Int. 1997;18(4):199-205.
6. Thomas RL, Wells BC, Garrison RL, Prada SA. Preliminary results comparing two methods of lateral column lengthening. Foot Ankle Int. 2001;22(2):107–119.
7. Adams SB, Simpson AW, Pugh LI, Stasikelis PJ. Calcaneocuboid joint subluxation after calcaneal lengthening for planovalgus foot deformity in children with cerebral palsy. J Pediatr Orthop. 2009;29(2):170–174.
8. Jara, ME. Evans osteotomy complications. Foot Ankle Clin N Am. 2017;22:573–585.
9. Bussewitz BW, DeVries JG, Hyer CF. Evans osteotomy and risk to subtalar joint articular facets and sustentaculum tali: a cadaver study. J Foot Ankle Surg. 2013; 52(5):594–597.
10. Viegas GV. Reconstruction of the pediatric flexible planovalgus foot by using an Evans calcaneal osteotomy and augmentative medial split tibialis anterior tendon transfer. J Foot Ankle Surg. 2003;42(4):199-207.