Medial Double Arthrodesis: Technique Guide and Tips

The Journal of Foot & Ankle Surgery 57 (2018) 364–369

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The Journal of Foot & Ankle Surgery j o u r n a l h o m e p a g e : w w w. j f a s . o r g

Medial Double Arthrodesis: Technique Guide and Tips Eric So, DPM 1, Christopher W. Reb, DO 2, David R. Larson, DPM 3, Christopher F. Hyer, DPM, MS, FACFAS 4 1Resident,

Grant Medical Center, Columbus, OH Surgeon, Assistant Professor, Division of Foot and Ankle Surgery, Department of Orthopaedics and Rehabilitation, College of Medicine, University of Florida, Gainesville, FL 3Fellowship-Trained Foot and Ankle Surgeon, Integrated Orthopedics, Phoenix, AZ 4 Fellowship Co-Director, Fellowship-Trained Foot and Ankle Surgeon, Foot and Ankle Center, Westerville, OH 2Orthopedic

A R T I C L E

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Keywords: flatfoot medial incision posterior tibial tendon dysfunction subtalar joint arthrodesis talonavicular joint arthrodesis

A B S T R A C T

The triple arthrodesis procedure remains the historical standard to treat complex hindfoot pathology. However, in recent data, the medial double arthrodesis has been documented to provide similar benefit with decreased complication rates compared with the triple arthrodesis. Therefore, increased interest in this procedure for the treatment of complex hindfoot pathologies has ensued. We describe the technical components of the medial double arthrodesis. © 2017 by the American College of Foot and Ankle Surgeons. All rights reserved.

The triple arthrodesis is the traditional treatment for stage III adult acquired flatfoot deformity. First described by Ryerson (1) in 1923, the triple arthrodesis was intended to correct deformity, improve pain, and achieve a plantigrade foot. Currently, this operation remains the standard treatment of complex hindfoot pathology. However, studies have shown that over time the joints adjacent to the triple arthrodesis, such as the ankle and midfoot joints, will show increased secondary arthritic degeneration (2). Concern about this long-term complication has led to the concept of limiting triple arthrodesis to the subtalar and talonavicular joints only. Thus, a new trend has emerged in the treatment of these deformities. The medial double arthrodesis is a viable and predictable alternative in the treatment of complex hindfoot deformities, such as adult acquired flatfoot deformity. This technique uses a single incision that begins slightly inferior to the medial malleolus, follows the course of the tibialis posterior tendon, and extends distally across the talonavicular joint (3). The advantages of this approach compared with the traditional double incision approach include a decreased risk of wound complications, equal joint exposure, superior reduction of the subtalar joint, and excellent clinical and functional outcomes (4–11). We describe the medial double technique for the treatment of adult acquired flatfoot deformity. In our experience, this technique provides

Financial Disclosure: Novastep funded the cadaveric laboratory. Conflict of Interest: None reported. Address correspondence to: Christopher F. Hyer, DPM, MS, FACFAS, Orthopedic Foot and Ankle Center, 300 Polaris Parkway, Suite 2000, Westerville, OH 43082. E-mail address: [email protected] (C.F. Hyer).

realignment of the deformity and adequate pain relief, minimizes wound complications, and yields high union rates.

Surgical Technique Exposure The patient was placed in the supine position under general anesthesia with regional blockade. A pneumatic thigh tourniquet was used for hemostasis. The straight incision was localized just posterior to the medial malleolus and extended to the medial cuneiform along the course of the tibialis posterior tendon (Fig. 1). The saphenous vein was preserved and translated dorsally away from the incision by cauterizing and transecting its smaller tributaries from the plantar side. The saphenous nerve often accompanies the vein and must be avoided. Additionally, the medial dorsal cutaneous nerve to the hallux, which can arrive from the saphenous or superficial peroneal nerves, can be encountered in the dorsal soft tissue flap. The superficial deltoid ligament was sharply incised (Fig. 2). If tenosynovium was tightly adherent to the undersurface of the superficial deltoid, a Freer elevator was used to dissect it free. Next, the tenosynovium was dissected off the tibialis posterior tendon, from the level of the medial malleolus to the navicular tuberosity, which improved visualization of the deeper structures. Perforating vessels required electrocautery in the plantar aspect of the tibialis posterior tendon sheath approximately midway between the medial malleolus and the navicular tuberosity. The posterior tibial tendon (PTT) sheath was exposed, incised, and inspected (Fig. 3). The most common sites of tendinosis are

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E. So et al. / The Journal of Foot & Ankle Surgery 57 (2018) 364–369

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Fig. 3. The posterior tibial tendon sheath is exposed, incised, and inspected. Fig. 1. Incision placement for medial double arthrodesis begins posterior to the medial malleolus and extends to the medial cuneiform along the course of the posterior tibial tendon.

behind the medial malleolus and in the area of the attachment to the navicular. The tendon can be debrided and repaired or simply excised, depending on the patient’s clinical symptoms and the gross appearance of the tendon. After excising or plantarly reflecting the tendon, the plantar calcaneonavicular spring ligament was inspected. By abducting the midfoot, the PTT was relaxed, and a self-retaining retractor was placed just distal to the medial malleolus to hold the tendon away from the plantar calcaneonavicular spring ligament. Its superomedial portion lies deep to the tibialis posterior tendon over the medial aspect of the talonavicular joint. Blunt dissection over the dorsal talonavicular joint capsule allowed a Hohmann retractor to be placed deep to the anterior neurovascular and tendinous structures. The dorsal talonavicular joint capsule was safely transected under direct visualization. The medial joint capsule was divided plantarly by following the arc of the talar head plantarly to the middle facet of the subtalar joint.

If the PTT was to be preserved, a thick cuff of tissue was reflected plantarly, inclusive of the medial joint capsule and the tibialis posterior tendon insertion, which were confluent at this level. If the PTT was to be excised, it was carefully transected at the level of the insertion into the navicular and plantar medial arch by leaving the medial joint capsule behind. In either event, medial talonavicular joint capsular closure was often possible at the end of the case. The flexor digitorum longus (FDL) tendon lies deep to the floor of the PTT sheath just superficial to the capsule overlying the posterior facet of the subtalar joint. It should be exposed and protected. To access its sheath, dissection should parallel the anatomic course of the PTT path, oriented approximately 45° plantarly and laterally (Fig. 4). A selfretaining retractor was then repositioned to hold the tibialis posterior tendon superiorly, creating a clear window for visualization of the FDL tendon. After exposure to the FDL tendon was obtained, a selfretaining retractor was used to separate the tibialis posterior tendon dorsally from the FDL tendon plantarly. Through this window, the deep deltoid ligament was visualized and sharply incised to access the posterior facet of the subtalar joint (Fig. 5).

Fig. 2. The superficial deltoid ligament is sharply incised.

Fig. 4. Dissection is parallel to the anatomic course of the posterior tibial tendon.


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Fig. 5. The deep deltoid ligament is visualized and sharply incised to access the posterior facet of the subtalar joint.

The medial profile of the posterior facet of the subtalar joint is double curved, with the apex dorsally and adjacent to the anatomic course of the FDL tendon. It then quickly curves laterally, adjacent to the tibial neurovascular structures. Blunt dissection between the capsule and the structures was achieved using a Freer elevator and then maintained with a Hohmann retractor while the capsule was divided along the joint line under direct visualization. Maintaining the FDL tendon as the inferior border will protect against neurovascular injury (Fig. 6). At this point, separation of the subtalar joint articular facets was still constrained by the talocalcaneal interosseous ligaments. A lamina spreader was placed into the tarsal canal to provide initial distraction, and a 0.25-in. curved osteotome was used to divide the talocalcaneal interosseous ligaments until the talus and calcaneus move apart. The lamina spreader was repositioned across to the sinus tarsi, and improved visualization was obtained.

Fig. 6. The flexor digitorum longus tendon should be maintained as the inferior border to protect against neurovascular injury.

Fig. 7. The middle facet of the subtalar joint is exposed.

Joint Surface Preparation A lamina spreader was placed in the middle facet to distract the joint and provide exposure to the posterior facet (Fig. 7). A combination of curved osteotomes and curettes were used to denude the cartilage. Angled curettes were ideal for debriding cartilage from the posterior facet (Fig. 8). To prevent iatrogenic injury to the tibial neurovascular structures, no instruments should cross the medial margin of the posterior facet. The lamina spreader was then released and reinserted at 180° to provide exposure of the middle facet and inferior margin of the talonavicular joint. After adequate cartilage resection,

Fig. 8. Joint preparation of the subtalar joint using manual instrumentation.



Fig. 9. The talonavicular joint is exposed.

the debris was removed. This was often achieved well with copious irrigation. We have found it best to use a solid drill bit to fenestrate the subchondral bone. Cannulated drill bits were prone to result in fracture when used for this purpose. The recommended diameter is 2.0 to 3.5 mm. The holes should be deep enough to penetrate the subchondral plate and closely set together. The drill shavings will accumulate in the joint space and obscure visualization. Thus, proceeding from far surfaces to near surfaces will allow for continuous progress in drilling the holes without having to stop to remove the debris. When drilling, it is important to maintain constant attention for safety, because many structures are at risk around the subtalar joint. Next, a 0.25-in. curved osteotome and mallet were used to fracture the subchondral bone, often called “shingling” or “fish scaling” owing to the serrated appearance of the bone left behind. Sequential penetrations should “connect the dots” between the fenestration holes and should be oriented 90° to one another. The process should be thorough and performed very carefully to leave the cortical shell of the bone intact and prevent inadvertently cleaving an area of bone away. The latter can occur at the narrow posterior aspects of the talar body, posterior facet of the calcaneus, or along any margin of the talar head or navicular. The lamina spreader was removed, and a pin distractor was used to distract the talonavicular joint (Fig. 9). This is recommended because the medial and plantar aspects of the talar head, which are uncovered in pes planovalgus, will often be soft. Thus, the lamina spreader frequently penetrated or deformed these areas of bone. Because of the relatively soft bone in the talar head, a rongeur was used for joint preparation. The navicular bone was often sclerotic and therefore was very hard. Cartilage debridement and joint preparation for the navicular was performed in the same manner described earlier in this section. Reduction and Fixation The subtalar joint was reduced into a neutral position, or no more than 5° of valgus relative to the long axis of the tibia, and was pinned with guide pins for 2 large-diameter partially threaded cannulated screws. It is imperative to assess the clinical position of the foot in the manually reduced position before proceeding with fixation. The midtarsal joint should remain “unlocked.” The hindfoot should appear neutral, with the midfoot abduction and forefoot supination

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corrected. It is often helpful to dorsiflex the hallux to plantarflex the medial columns of the midfoot while maintaining the reduction. Pinning the talus in place with 2 pins out of plane is advisable. Finally, ankle dorsiflexion must be sufficient to allow the alignment to be maintained throughout the ankle range of motion. A Silfverskiold examination was completed to determine whether gastrocnemius recession or tendo-Achilles lengthening would be needed. Either headed or headless screws can be used for hindfoot fixation. The number of screws used was at the surgeon’s discretion. When 1 screw was to be used, it was inserted with a retrograde (calcaneus into talus) orientation, perpendicular to the posterior facet of the subtalar joint, and centered within the calcaneus and talar body. When 2 screws were used, 1 was localized perpendicular to the posterior facet in the lateral half of the calcaneus tuberosity and talar body, and 1 was localized in the medial half of the calcaneus tuberosity and across the middle facet into the center of the talar head or neck. The latter can be inserted using either a retrograde or an antegrade orientation (talar neck into calcaneus). Pin insertion was monitored using intermittent fluoroscopic image intensification. The critical views to obtain are the axial view of the calcaneus (Harris view), lateral hindfoot, anteroposterior, and mortise views of the ankle, and an anteroposterior view of the midfoot. The Harris view will confirm the position of the wires in the calcaneus tuberosity relative to the posterior and middle facets. The lateral view of the hindfoot will confirm their sagittal position within the talar body and talar head. The anteroposterior and mortise views of the ankle are used to ensure that the wires are not in the ankle joint gutters. Finally, anteroposterior view of the midfoot will confirm that the medial wire is within the talar head and neck. All the views of a given wire were checked each time it was repositioned. Using a standard technique, the screws were then inserted in a percutaneous fashion. For headed screws, meticulous countersinking is strongly recommended to minimize the frequency of symptomatic screw heads. The posterior cortex of the calcaneus tuberosity is composed of a thick zone of dense bone. It is important to ensure the view is orthogonal to the guide wire to obtain an accurate assessment of the countersink position. The screw and thread lengths were carefully chosen to ensure that all threads would be past the subchondral plate on the talar side of the arthrodesis. When seating the screws, care should be taken for several reasons. Overtightening of a screw can result in overpenetration, loss of screw purchase within the talus because the threads begin to function as an auger once forward progression of the screw has ceased. Also, in soft bone, overtightening can cause anterior subluxation of the calcaneus relative to the talus, resulting in loss of contact area between the talus and calcaneus. Next, reduction of the talonavicular joint was confirmed clinically and with fluoroscopic views. Manual abduction pressure was applied to the talar head with a simultaneous pronatory force on the first ray to reduce the medial column. The necessary views to obtain are the anteroposterior view of the midfoot, lateral view of the foot, and anteroposterior and mortise views of the ankle. The anteroposterior view of the midfoot is used to confirm that talar head coverage by the navicular has been restored such that collinearity of the long axes of the talus and the mechanical axis of the first ray is present. On the lateral view, the long axes of the talus and first metatarsal should also be collinear (Meary’s angle of 0°). The ankle views should confirm that penetration into the ankle joint gutters has not occurred. The talonavicular joint can be fixated with a variety of constructs. The senior author’s (C.F.H.) preferred construct is two 4.0mm partially threaded cannulated screws based within the navicular tuberosity and a compression staple across the dorsal aspect of the lateral half of the talonavicular joint. The first guide pin was localized just proximally to the articulation between the navicular and


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medial cuneiform in the upper third of the navicular. On the anteroposterior view of the midfoot, the pin should be oriented into the lateral half of the talar body. On the lateral view, it should be parallel to the dorsal neck of the talus. The second guide pin was localized to the plantar half of the navicular just proximal to the articulation of the medial cuneiform and was directed into the medial half of the talar body parallel to the middle facet of the subtalar joint. Screw fixation across the talonavicular joint should follow the same principles stated in the previous paragraph. Finally, the surgical staple is localized into the lateral half of the talonavicular joint clinically. An oblique view of the midfoot is used to confirm that it is ideally aligned with the long axis of the third ray. This will give the broadest spread of fixation points between implants and give the surgical staple a large area of purchase within the navicular body. Final fluoroscopic views were obtained. These consisted of 3 views of the ankle, 3 views of the foot, and an axial view of the calcaneus. It is imperative to obtain and save quality views because suboptimal radiographic views obtained after surgery can give a false impression of implant position (Fig. 10). Closure After irrigation, the attenuated, diseased portion of the calcaneonavicular spring ligament was excised, and anatomic closure of the talonavicular and subtalar joint capsule was achieved using size 0 absorbable braided suture. If the tibialis posterior tendon was preserved, this was restored its attachment to the navicular. The attachment can be reinforced using transosseous suture below the dorsal cortex of the navicular tuberosity. The guidewire for the smaller cannulated screw was used to create pilot holes on the subchondral side of the navicular tuberosity. Next, the superficial deltoid was repaired with size 0 absorbable braided suture (Fig. 11). A subcuticular layer of closure using 3-0 absorbable braided suture was achieved, and the skin was closed with 3-0 nonabsorbable suture. The heel wounds were closed with nonabsorbable suture or skin staples. The tourniquet was released, with compression maintained on the wounds. After 1 minute, the pedal pulses were palpated, and digital capillary refill was assessed. The wounds were dressed with nonadherent gauze, 4 × 4-in. gauze, absorptive pads, and sterile cast padding. Finally, a well-padded posterior stabilized short leg splint was applied, with the ankle held in neutral dorsiflexion. Fig. 10. (A) Anteroposterior, (B) lateral, and (C) medial oblique images of a medial double arthrodesis.

Aftercare The first follow-up examination occurred 5 to 7 days for wound evaluation and pain control. Short-leg cast immobilization was maintained for 4 to 6 weeks, with a cast change midway. Osseous union can be expected by 6 to 8 weeks postoperatively. At that time, the patient was transitioned into a walking boot for an additional 3 to 4 weeks, with physical therapy with progression through phases of rehabilitation as tolerated by the patient. The patient can resume regular activities of daily living at that time. The recommended follow-up period is 6 to 9 months. Discussion The indications for triple arthrodesis include arthritis of the hindfoot, stage III tibialis posterior tendon dysfunction, and neuromuscular disease-mediated hindfoot deformities (1,2,12–19). The indications for triple arthrodesis are also good indications for a medial double arthrodesis, unless severe arthritic changes are present in the calcaneocuboid joint. However, rigid adult acquired flatfoot deformity has been most commonly and traditionally treated with triple

arthrodesis (19). Smith et al (18) reported on patients with triple arthrodesis with a mean follow-up of 14 years. The satisfaction rate was 93%, although many patients experienced limitations in shoes and intolerance of walking on uneven ground. Although triple arthrodesis can offer satisfactory results, wound complications, malunion, and adjacent joint arthroses are well-reported complications (12–19). The rate of wound complications with triple arthrodesis has ranged from 2% to 33% (7,12–15,17). This might be due to the resulting tension of the lateral incision after correction of the pes planovalgus deformity. With the medial double approach, the surgical exposure is taken away from the tension of the foot, thus avoiding the potential difficulties that can be associated with contracted lateral soft tissue structures. Another complication of triple arthrodesis is malunion deformity. If the triple arthrodesis is fused in a varus attitude, painful lateral column overload can occur, which can require revision surgery. A triple arthrodesis fused in valgus will result in deltoid insufficiency. A treatment algorithm for malunited triple arthrodesis has been established



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landmark when attempting to gain access to the subtalar joint using the medial approach (3). A cadaveric study showed that using a single medial approach, 91% of the subtalar and talonavicular joint surfaces and 90% of the calcaneocuboid joint surface could be prepared (6). In a pes planovalgus foot deformity, the talar head will be subluxed medially; thus, the talonavicular joint will be even more readily accessible. In conclusion, we believe that the medial double arthrodesis is an effective alternative to triple arthrodesis. This technique eliminates lateral wound complications, allows the calcaneocuboid joint to act as a force-dissipating joint, and provides similar clinical results. The exposure is straightforward and can be performed safely. We hope we have provided a technique guide for foot and ankle surgeons eager to add this technique to their armamentarium. The reported case series lacks long-term follow-up data, and further investigation is justified. References

Fig. 11. The deep and superficial deltoid ligaments are repaired.

(20). Furthermore, loss of hindfoot motion after triple arthrodesis will lead to overload to the adjacent joints, causing degenerative changes (17). Some studies have observed degenerative changes to the ankle joint in ~30% of nonrheumatoid patients 5 years after the index surgery (2). Medial double arthrodesis might result in lower rates of adjacent joint arthritis because of the remaining motion of the lateral column. This motion is observed radiographically as diastasis occurs at the calcaneocuboid joint in the medial double arthrodesis (20). This distraction theoretically decreases the joint pressures and allows for remodeling of the subchondral plate (20). It is reasonable to believe that the calcaneocuboid might thus act as a force-dissipating factor during ambulation (21). However, this has not been proved by in vivo studies. The radiographic results of medial double arthrodesis have been comparable to those of triple arthrodesis. The fusion rates of the medial single incision technique have been reported at 89% to 100% (4,5,7–11). Deformity correction of the forefoot and hindfoot using the single medial incision has yielded satisfactory results. Sammarco et al (9) observed 15 modified double arthrodesis in 14 patients at an average 18-month follow-up period and noted statistically significant improvement in the anteroposterior talar–second metatarsal angle and lateral talocalcaneal and talar–first metatarsal angle. Devries and Scharer (21) compared 20 triple arthrodeses and 20 modified double arthrodeses and found that both procedures are equally and adequately capable of correcting hindfoot deformity. The proximity to the neurovascular bundle can be a deterrent to performing medial double arthrodesis. Galli et al (3) reviewed the structures at risk during the medial double arthrodesis. They found that the neurovascular bundle was, on average, 21.19 mm from the middle facet of the subtalar joint (3). They suggested that the medial approach is an effective and safe alternative to the multiple incision technique. The tibialis posterior tendon can serve as a dissection

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