DEFINITION

An isolated subtalar arthrodesis can be used in the treatment of a myriad of different hindfoot conditions, including primary arthrosis of the subtalar joint, posttraumatic arthritis secondary to a talar or complex calcaneal fracture, rheumatoid arthritis, and talocalcaneal coalition.

Other indications include posterior tibial tendon insufficiency and any neuromuscular disorder presenting with instability of the subtalar joint.

When the pathologic process resides solely in the talocalcaneal articulation, isolated subtalar arthrodesis is preferred over a triple arthrodesis for its preservation of hindfoot motion, its decreased potential for development of degenerative changes in neighboring joints, its relative simplicity, and its lower potential for pseudarthrosis of the talonavicular and calcaneocuboid joints.

 

 

ANATOMY

 

The term subtalar refers to the articulation between the anterior, middle, and posterior facets of the inferior talus and the corresponding anterior, middle, and posterior facets located on the superior aspect of the calcaneus.

 

The subtalar joint is a “plane type” synovial joint with a weak fibrous capsule supported by medial, lateral, and posterior talocalcaneal ligaments as well as an interosseous talocalcaneal ligament.

 

This important articulation provides for inversion and eversion of the hindfoot, which is critical for proper adaptation of the foot during ambulation on uneven terrain and for dissipation of heel-strike forces.

 

Isolated fusions of the subtalar joint have been shown to reduce talonavicular joint motion by 74% and calcaneocuboid joint motion by 44%.1

PATHOGENESIS

 

Numerous causes of subtalar joint arthritis exist, including the following:

 

 

Primary osteoarthrosis: articular cartilage degeneration of unknown etiology

 

Secondary arthritis: caused by either traumatic articular cartilage damage or increased joint stresses following an arthrodesis of an adjacent joint

 

 

Inflammatory arthritis: autoimmune joint destruction (eg, rheumatoid arthritis, psoriatic arthritis) Other etiologies that may necessitate an isolated subtalar arthrodesis include the following:

 

Talocalcaneal coalition: abnormal fusion between the talus and calcaneus, most likely secondary to a failure of segmentation of the primitive mesenchyme

 

Instability or deformity secondary to muscular imbalance (eg, posterior tibial tendon insufficiency, Charcot-

Marie-Tooth disease, poliomyelitis)

 

NATURAL HISTORY

 

Depends on specific etiology

 

In general, the various forms of subtalar arthritis are progressive in nature.

 

Despite waxing and waning of symptoms, no spontaneous resolution of the pathologic process is noted.

 

PATIENT HISTORY AND PHYSICAL FINDINGS

 

A problem-focused history should include direct questioning regarding the exact nature of the symptoms, specific location, duration and progression of symptoms, aggravating or alleviating factors, prior therapeutic interventions, and functional disability.

 

 

Patients often complain of lateral ankle pain and difficulty ambulating on uneven terrain. The pain often gets better with rest and may be mitigated by wearing high-top shoes.

 

Physical examination findings consistent with subtalar joint arthritis may include the following:

 

 

Hindfoot swelling

 

Tenderness within the sinus tarsi

 

 

 

Pain with inversion and eversion of the hindfoot Limited range of motion of the subtalar joint Antalgic gait

 

To help localize the pathology to the subtalar joint complex, palpate and observe the sinus tarsi (the soft tissue depression just anterior and slightly distal to lateral malleolus) for swelling.

 

Passively dorsiflex the ankle to neutral to lock the talus within the mortise. Descriptions of normal subtalar range of motion vary widely. Therefore, it is useful to describe the range as a fraction of the asymptomatic, contralateral side. Pain and decreased range of motion may be indicative of subtalar joint arthritis. Complete loss of range of motion is consistent with a tarsal coalition.

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Plain radiographs should include standing anteroposterior (AP), lateral, and oblique views of the foot and standing AP, lateral, and mortise views of the ankle.

 

Additional plain radiographs may include a Broden view (lower extremity internally rotated 45 degrees; x-ray tube angled 10 to 40 degrees cephalad) to evaluate the posterior subtalar facet and a Canale view (AP view of the foot in

 

50

15 degrees of pronation with tube angled 75 degrees from the horizontal) to evaluate the sinus tarsi.

 

 

 

FIG 1 • Posttraumatic arthritis of the subtalar joint. Note the narrowing of the joint space, subchondral sclerosis, subchondral cysts, and osteophyte formation.

 

 

Radiographic findings consistent with a degenerative process include joint space narrowing, osteophytes, and subchondral cysts or sclerosis (FIG 1).

 

Computed tomography (CT) and magnetic resonance imaging offer little additional information about the arthritic process involving the subtalar joint, but they may identify a previously undiagnosed tarsal coalition or concomitant soft tissue pathology.

 

A diagnostic injection of a local anesthetic into the subtalar joint may help localize the patient's complaints, and if a corticosteroid is added to the injection, this procedure may provide significant short-term relief.

 

DIFFERENTIAL DIAGNOSIS

Primary osteoarthrosis Posttraumatic arthritis Inflammatory arthritis Acute fracture

Sinus tarsi syndrome

Instability of the subtalar joint or subtalar sprain Fibrous or cartilaginous talocalcaneal coalition Subtalar loose body

 

 

NONOPERATIVE MANAGEMENT

 

 

Subtalar joint arthritis is initially managed nonoperatively in all patients. Nonoperative management strategies may include the following:

 

Activity modification

 

 

Nonsteroidal anti-inflammatory medications Intra-articular corticosteroid injection

 

Use of an ankle-foot orthosis or UCBL orthosis to limit hindfoot motion. Other options include an air stirrup or high-top boot.

 

Patellar tendon-bearing brace to unload the subtalar joint

 

Conservative treatment may also be indicated in patients with significant peripheral vascular disease, active infection, inability to comply with the postoperative regimen, or a severe sensory neuropathy.

 

SURGICAL MANAGEMENT

 

For patients who do not achieve relief with an adequate trial of nonoperative management, surgical intervention is warranted.

 

Preoperative Planning

 

Plain radiographs are reviewed for deformity or malalignment, loose bodies, or retained hardware from a prior surgery.

 

CT or magnetic resonance imaging scans are reviewed, if available.

 

Positioning

 

The patient is placed supine on the operative table, and the sole of the foot is aligned with the end of the bed to facilitate later screw insertion into the heel.

 

A pneumatic tourniquet is placed around the upper thigh, and a soft bump is placed beneath the ipsilateral sacrum to internally rotate the operative extremity. Placement of the bump beneath the sacrum, rather than beneath the buttock, will prevent any undue pressure on the sciatic nerve.

 

The fluoroscopy unit is brought in from the contralateral side of the bed.

 

A tourniquet is elevated to a pressure 100 mm Hg greater than the patient's systolic pressure.

TECHNIQUES

• Exposure

The incision begins approximately 1 cm below the tip of the lateral malleolus and progresses distally to a point just shy of the base of the fourth metatarsal (TECH FIG 1A). Alternatively, a modified Ollier incision may be used.

The subcutaneous tissue is incised in line with the skin incision, and preemptive hemostasis of any crossing vessels is performed using electrocautery.

The origin of the extensor digitorum brevis muscle is identified and elevated along with the sinus tarsi fat pad as a distally based flap. A small cuff of tissue is preserved proximally for later reattachment of this flap (TECH FIG 1B,C).

At this point, the subtalar joint is well visualized.

 

 

 

 

TECH FIG 1 • Surgical approach. A. Incision. (continued)

 

 

51

 

 

 

TECH FIG 1 • (continued) B. Exposure of the extensor digitorum brevis muscle, sinus tarsi fat pad, and peroneal tendons. C. Elevation of extensor digitorum brevis and sinus tarsi fat pad as a distally based flap.

• Preparation of the Arthrodesis Site

   

  After adequate visualization of the lateral aspect of the subtalar joint has been attained, any remaining fatty or ligamentous tissue is removed from the joint with a rongeur (TECH FIG 2A).

   

  Using a straight curette or chisel, the articular cartilage is removed from the lateral half of the inferior talus and superior aspect of the calcaneal facets (TECH FIG 2B). Note that the goal is to maintain the normal, curved contours of the articular facets.

   

  A lamina spreader is then inserted to allow access to the medial half of the joint, which is then cleared of its articular cartilage using a combination of straight and curved curettes (TECH FIG 2C).

   

   

   

  TECH FIG 2 • Preparation of the arthrodesis site. A. Removal of soft tissues from the subtalar joint. B. Removal of the lateral articular cartilage with a curette. C. Insertion of a lamina spreader and removal of the remaining medial articular cartilage. D. Creation of vascular channels with a K-wire. E. Reattachment of the extensor digitorum brevis to its origin after insertion of a tibial bone graft.

   

   

  After complete removal of all articular cartilage, Kirschner wire (K-wire) holes are created in the denuded inferior surface of the talus and the superior surface of the calcaneus to produce vascular channels that will aid in the fusion (TECH FIG 2D). These K-wire holes may be further augmented with larger holes created through the use of a 3-mm burr and by feathering of the subchondral bone with a curved osteotome.

   

  Cancellous autograft obtained from the proximal tibia (see Techniques: Harvesting of Tibial Bone Graft and TECH FIG 4) is inserted into the subtalar joint, and the extensor digitorum brevis muscle is reattached to its site of origin to seal the arthrodesis site (TECH FIG 2E).

   

  52

• Insertion of Hardware

   

  At this point, the subtalar joint is positioned into 5 degrees of valgus.

   

  A 1-cm incision is created at the apex of the heel for insertion of a guide pin, which is subsequently driven through the posterior tuberosity, across the subtalar joint, and into the talar neck (TECH FIG 3A). This guide pin is placed fluoroscopically using axial (Harris) heel and lateral views.

   

  A second guide pin is placed through a 1-cm incision just medial to the anterior tibialis tendon into the dorsomedial aspect of the talar neck, across the subtalar joint, and into the posterior calcaneal tuberosity

  (TECH FIG 3B).

   

   

   

  TECH FIG 3 • Internal fixation. A. Placement of the first guide pin and screw from the apex of the calcaneal tuberosity. B. Placement of the second guide pin and screw from the dorsomedial aspect of the talar neck. C. Final fluoroscopic images.

   

   

  The initial guide pin is occasionally overreamed proximally (not necessary with self-drilling, self-tapping screws), and a 6.5-mm partially threaded cancellous lag screw of an appropriate length is inserted after minimal use of the cannulated countersink. This procedure is repeated for the dorsomedial lag screw.

   

   

  Final fluoroscopic images are obtained to verify proper screw position (TECH FIG 3C). The tourniquet is released and hemostasis is secured.

   

  The wound is then closed using 2-0 Vicryl for the subcuticular layer and 3-0 nylon horizontal mattress sutures for the skin.

• Harvesting of Tibial Bone Graft

   

  An incision beginning 1 cm distal to the distal aspect of the tibial tubercle and 1 cm lateral to the anterior tibial crest is carried distally for a length of 4 cm (TECH FIG 4A).

   

  The fascia overlying the anterior compartment musculature is divided in line with the skin incision.

   

  Muscle and periosteum overlying the anterolateral face of the tibia is elevated using a periosteal elevator, thus exposing the anterolateral cortex (TECH FIG 4B).

   

   

   

  TECH FIG 4 • Harvesting of the tibial bone graft. A. Incision. B. Periosteal elevation along the anterolateral cortex. (continued)

   

   

  A 1 × 1-cm2 (or elliptical) window is created in the center of the anterolateral face and a curette is inserted into the window for removal of cancellous graft (TECH FIG 4C,D).

   

  After an adequate amount of cancellous graft is harvested, the window is sealed with the previously removed square plug of bone and a layered closure of the fascia, subcutaneous tissue, and skin is performed.

   

  Time from graft harvest to insertion into the fusion site should be less than 30 minutes.

   

   

  53

   

   

   

   

  TECH FIG 4 • (continued) C. Creation of a 1 × 1-cm2 window. D. Removal of the cancellous autograft with a curette.

• Subtalar Arthrodesis (Courtesy of Mark E. Easley, MD)

Background and Imaging

 

 

A 38-year-old man with left hindfoot arthritis History of twisting injury to left ankle and foot

 

 

 

TECH FIG 5 • A 38-year-old man with left hindfoot arthritis, weight-bearing radiographs. A. AP ankle view. B. Mortise ankle view. C. Lateral foot radiograph. D. Hindfoot alignment view. E. CT demonstrating left subtalar arthritis.

 

 

 

When carefully interviewed, notes long-standing stiffness to the hindfoot, suggestive of a tarsal coalition Failed nonoperative treatment

 

Opted for surgical management

 

Imaging suggests hindfoot arthritis and possible middle facet coalition (TECH FIG 5)

 

 

54

 

 

 

TECH FIG 6 • Modified lateral decubitus position with beanbag to rotate patient, allowing improved access to the lateral foot. A firm support may be placed under the operated foot.

Positioning

 

Modified lateral decubitus position with beanbag to rotate patient, allowing improved access to the lateral foot (TECH FIG 6)

 

A firm support may be placed under the operated foot.

 

Thigh tourniquet; although if no Achilles tendon is warranted, a calf tourniquet is feasible

Exposure

 

 

Longitudinal approach from tip of fibula toward base of fourth metatarsal Sural nerve protected (TECH FIG 7A,B)

 

Peroneal tendons retracted plantarly

 

Fascia overlying extensor digitorum brevis muscle divided

 

 

Extensor digitorum brevis muscle elevated and retracted dorsally (TECH FIG 7C,D) Subtalar joint exposed through sinus tarsi (TECH FIG 7E,F)

 

 

Calcaneofibular ligament protected with blunt retractor Joint distraction (TECH FIG 7G-I)

 

Distractor with one pin in the talus and one in the calcaneus if often effective and permits optimal access to the subtalar joint (TECH FIG 7J-L)

 

Alternatively, a lamina spreader may be used within the joint (TECH FIG 7M,N).

Joint Preparation

 

Remove residual cartilage from the posterior subtalar joint (inferior talus and posterior calcaneal facet)

and the middle subtalar joint (inferior medial talus and the middle subtalar facet).

 

A chisel or sharp periosteal elevator may be used.

 

The most medial aspect of the joint usually requires use of a curette.

 

Penetrate the subchondral bone of all surfaces to be fused.

 

Allows for access to marrow elements, creates channels for healing, and increases surface area for healing

 

A small-diameter chisel or a drill may be used (TECH FIG 8A).

 

A curette allows for access to the medial joint surfaces (TECH FIG 8B).

 

Joint preparation must include the medial joint.

 

Visualization of the flexor digitorum longus (FHL) tendon medially indicates that the medial joint has been accessed (TECH FIG 8C,D).

Hindfoot Alignment, Joint Reduction, and Provisional Fixation

 

Optimize bone apposition at the arthrodesis sites.

 

Bone graft at the surgeon's discretion (TECH FIG 9A); may improve healing when contact between surfaces not ideal

 

 

Hindfoot valgus (TECH FIG 9B); avoid varus Provisional fixation

 

Usually with guide pins for planned cannulated screws

 

 

One medial and one lateral guide pin, placed from calcaneus into talus (TECH FIG 9C) Lateral pin usually into lateral talar body (TECH FIG 9D)

 

 

Medial pin usually into medial talar body or neck (TECH FIG 9E) Both pins originate in calcaneus and are directed into the talar body.

 

Both pins should be started in the lateral one-half of the plantar calcaneus.

 

If the medial pin is started medially, it may penetrate the medial calcaneal cortex and risk injuring the medial neurovascular structures or tendons.

 

Fluoroscopic confirmation of satisfactory alignment, bony apposition, and guide pin position

 

Lateral foot view: optimal medial and lateral pin position (TECH FIG 9F); used to determine ideal screw length to use as a reference for the depth gauge over the guide pins

 

Mortise view of the ankle: optimal medial and lateral pin position in the talar dome/body

 

Harris heel view (TECH FIG 9G): to ensure that medial pin is contained in the calcaneus and is not penetrating the medial calcaneal cortex

Fixation

 

 

Through stab incisions in the heel, insert cannulated screws over the guide pins (TECH FIG 10A). Compression screws may improve bone contact for healing.

 

Combination of one compression screw and one positional screw is also satisfactory (TECH FIG 10B).

 

In select cases, consideration may be given to adding a third, more anterior screw from the calcaneus into the talar neck (TECH FIG 10C,D).

 

55

 

 

 

TECH FIG 7 • A. Longitudinal approach from tip of fibula toward base of fourth metatarsal. B. Avoid initial deep incision: The sural nerve is in this approach. C. Exposing fascia of extensor digitorum brevis deep to the peroneal tendons. D. Extensor digitorum brevis elevation. Note peroneal tendons retracted plantarly. E. Posterior subtalar joint exposed through sinus tarsi. F. Elevator in the posterior subtalar joint.

G. Blunt elevator being inserted. (continued)

 

 

56

 

 

 

TECH FIG 7 • (continued) H. Elevator deep to calcaneofibular ligament. I. Calcaneofibular ligament retracted. J. Pin placed in talar body. K. Distraction device placed over pins, including second pin in calcaneus. L. Joint distracted. M. Chisel to elevate residual cartilage from inferior talus. N. Chisel used to penetrate subchondral bone. Note lamina spreader being used in lieu of pin distractor.

 

 

57

 

 

 

TECH FIG 8 • A. Drill being used to penetrate subchondral bone. B. Curette used to remove the most medial cartilage and prepare the subchondral bone. C,D. Joint preparation must include the entire medial joint. The FHL is the reference that all of the medial joint has been accessed. C. FHL visualized deep within joint. D. Motion of the great toe to confirm medial structure deep in the subtalar joint is the FHL tendon.

 

 

 

TECH FIG 9 • A. Bone grafting after joint preparation. B. With elevation of the leg and perspective from the posterior heel, hindfoot valgus is confirmed. (continued)

 

 

58

 

 

 

TECH FIG 9 • (continued) C-G. Provisional fixation. C. Guide pins inserted from posterior heel from calcaneus into talus. D. AP fluoroscopic view confirming appropriate coronal plane position for lateral guide pin. E. Mortise view demonstrating trajectory for medial guide pin. F. Lateral fluoroscopy with satisfactory position for both guide pins. G. Harris heel view confirming that medial guide pin does not penetrate the medial calcaneal cortex. Note that both pins originate lateral to the calcaneal midline.

 

 

 

TECH FIG 10 • A. Cannulated screws inserted from calcaneus into talus over guide pins. B. Lateral fluoroscopic view. Note that all of the threads of the initially inserted compression screw crossed the

subtalar joint. If desired, a supplemental anterior subtalar screw may be inserted. (continued)

 

 

59

 

 

 

 

TECH FIG 10 • (continued) C. Guide pin. D. Cannulated screw.

 

 

Confirm hindfoot valgus position and satisfactory ankle range of motion.

 

Fluoroscopic confirmation of proper screw position and alignment: lateral foot, ankle mortise views

Closure

 

Irrigation

 

Further bone grafting in the sinus tarsi

 

 

Reapproximate extensor digitorum brevis fascia, if possible. Routine subcutaneous and skin closure

 

 

Routine wound closure (TECH FIG 11) Splinting with ankle in neutral position

 

 

 

TECH FIG 11 • Ideally, the extensor digitorum brevis muscle and fascia are approximated deep to the subcutaneous closure.

 

Postoperative Care

 

 

Overnight stay versus discharge to home with pain pump Follow-up at 2 to 3 weeks

 

 

Wound check, suture removal, and short-leg cast Initiate partial weight bearing for additional 4 weeks.

 

 

Follow-up at 6 to 7 weeks Wound check

 

Radiographs, simulated weight bearing

 

Lateral foot

 

 

Mortise view of the ankle Broden view

 

 

If concern for inadequate healing: Continue short-leg cast

 

Maintain partial weight bearing only

 

 

If satisfactory progression, cam boot and gradually advance weight bearing Follow-up at 10 to11 weeks (see FIG 2)

 

Weight-bearing radiographs

 

If concern for inadequate healing, consider CT of ankle and hindfoot to assess.

PEARLS AND PITFALLS

Preparation

of joint surfaces

• Remove articular cartilage only.

• Preservation of subchondral bone will provide structural support and will allow for better coaptation.9

• Use of a K-wire to perforate the residual subchondral bone of the talus and

calcaneus will allow communication between the marrow cavities and the arthrodesis site and will aid in the fusion.

Positioning

of arthrodesis

• The arthrodesis is ideally placed in 5 degrees of valgus.6

• Fusing the subtalar joint in varus will lock the transverse tarsal joint, leading to increased lateral forefoot pressures with weight bearing.10

• Fusing the subtalar joint in excessive valgus can potentially lead to subfibular

impingement.10

Internal

fixation

• Use of a partially threaded cancellous lag screw with a short threaded region will

  reduce the likelihood of any threads crossing the arthrodesis site.

• Countersinking of the screw heads and avoidance of a screw head placed on the weight-bearing plantar surface of the calcaneus will reduce complaints related to the hardware.

60

If satisfactory healing, transition to regular shoe

 

 

POSTOPERATIVE CARE

 

The extremity is placed in a well-padded, non-weightbearing short-leg plaster cast before the patient leaves the operating room.

 

In the recovery room, the cast is widely split along its anterior surface to allow for immediate postoperative swelling.

 

The patient is seen in clinic at 2 weeks postoperatively, at which point the initial cast and sutures are removed.

 

 

 

FIG 2 • Three-month follow-up weight-bearing radiographs of the patient in TECH FIGS 5, 6, 7, 8, 9, 10, 11. A. AP view of the ankle demonstrating acceptable screw position in talar body. B. Mortise view. C. Lateral view suggesting satisfactory bony apposition and screw position. D. Broden view suggesting early bridging trabeculation in subtalar joint.

 

 

A short-leg fiberglass cast is applied and the patient is kept non-weight bearing.

 

At the 6-week mark, radiographs are obtained and the patient is converted to a fiberglass short-leg walking cast.

 

If radiographic union is appreciated at the 12-week appointment (FIG 2), casting is discontinued and gentle range of motion of the foot and ankle is initiated. At this point, the patient is often placed in a cam walker to ease the transition from the cast to normal shoe wear.

 

 

61

 

OUTCOMES

At an average of nearly 5 years of follow-up, Mann et al12 reported a 93% satisfaction rate with isolated subtalar arthrodesis.

 

In another study by Mann and Baumgarten,11 subtalar joint fusion in 6 degrees of valgus resulted in the maintenance of approximately 50% of the transverse tarsal joint motion as compared with the unaffected, contralateral extremity. In this same study, minimal degenerative changes were noted at the talonavicular

and calcaneocuboid joints, a finding that was not clinically significant.11

In a retrospective study, Dahm and Kitaoka3 demonstrated a 96% union rate in 25 adult feet.

Similarly, Easley et al4 demonstrated a 96% subtalar fusion rate after excluding smokers, revision arthrodeses, fusions using a structural graft, and subtalar fusions performed in an extremity with a previously fused tibiotalar joint.

 

 

COMPLICATIONS

Infection8 Nonunion4,7,10 Malalignment

Varus leading to increased lateral column forefoot pressures6,10 Valgus leading to subfibular impingement6,10

Symptomatic hardware4 Superficial wound breakdown2 Reflex sympathetic dystrophy5

 

 

REFERENCES

1. Astion DJ, Deland JT, Otis JC, et al. Motion of the hindfoot after simulated arthrodesis. J Bone Joint Surg Am 1997;79(2):241-246.

    

    

2. Chandler JT, Bonar SK, Anderson RB, et al. Results of in situ subtalar arthrodesis for late sequelae of calcaneus fractures. Foot Ankle Int 1999;20:18-24.

    

    

3. Dahm DL, Kitaoka HB. Subtalar arthrodesis with internal compression for posttraumatic arthritis. J Bone Joint Surg Br 1998;80(1): 134-138.

    

    

4. Easley ME, Trnka HJ, Schon LC, et al. Isolated subtalar arthrodesis. J Bone Joint Surg Am 2000;82(5):613-624.

    

    

5. Flemister AS Jr, Infante AF, Sanders RW, et al. Subtalar arthrodesis for complications of intra-articular calcaneal fractures. Foot Ankle Int 2000;21:392-399.

    

    

6. Kile TA, Bouchard M. Degenerative joint disease of the ankle and hindfoot. In: Thordarson DB, ed. Orthopaedic Surgery Essentials: Foot and Ankle. Philadelphia: Lippincott Williams & Wilkins, 2004:195-220.

    

    

7. Kitaoka HB. Talocalcaneal (subtalar) arthrodesis. In: Kitaoka HB, ed. Master Techniques in Orthopaedic Surgery: The Foot and Ankle, ed 2. Philadelphia: Lippincott Williams & Wilkins, 2002:387-399.

    

    

8. Lin SS, Shereff MJ. Talocalcaneal arthrodesis: a moldable bone grafting technique. Foot Ankle Clin 1996;1:109-131.

    

    

9. Lippert FG, Hansen ST. Subtalar arthrodesis. In: Lippert FG, Hansen ST, eds. Foot and Ankle Disorders: Tricks of the Trade. New York: Thieme, 2003:133-139.

    

    

10. Mann RA. Arthrodesis of the foot and ankle. In: Coughlin MJ, Mann RA, eds. Surgery of the Foot and Ankle, ed 7. St Louis: Mosby, 1999:651-699.

     

     

11. Mann RA, Baumgarten M. Subtalar fusion for isolated subtalar disorders. Preliminary report. Clin Orthop Relat Res 1988;(226):260-265.

     

     

12. Mann RA, Beaman DN, Horton GA. Isolated subtalar arthrodesis. Foot Ankle Int 1998;19:511-519.