During the last few decades, advances have been made in the management of diseases around the ankle. Ankle reconstruction techniques such as fusion and joint replacement are now gaining popularity with much more promising outcomes.
Painful disabling arthrosis of the ankle may occur after trauma or chronic instability, or it may be related to inflammatory joint diseases, osteochondritis dissecans, avascular necrosis of the talus, infections, or neuropathy.1
Ankle fusion has been a commonly performed operative procedure, and Charnley type of resection arthrodesis probably has been the most popular method, though the complication rates has been reported as high as 60%. Several modifications have been made to improve Charnley type ankle fusion.2
Tibio-talo-calcaneal fusion using condylar blade plate, cancellous bone screws, or a locked retrograde intramedullary (IM) nailing is a procedure that can be used successfully to treat disabling foot and ankle arthropathy and is a reasonable salvage alternative to amputation. The use of a retrograde IM nailing in patients with Charcot arthropathy appears as an alternative to amputation. It should also be considered for patients with significant posttraumatic arthrosis with bone loss after distal tibial plafond fractures, concomitant subtalar arthrosis, or severe oateopenia in patients with rheumatoid arthritis.
Developing countries, with limited facilities, face a lot of problems in treating these painful disabling arthroses of the ankle. IM nailing is biomechanically stiffer than cancellous screws in all bending and torsional forces, and this construct may aid in maintaining alignment of the hindfoot during union and faster healing rate through increased stability. IM nailing can be an alternative to ankle replacement surgery.3
The indications for ankle fusion using IM nails are:
Infections, eg, tuberculosis, Hansen's disease
Salvage of failed total ankle arthroplasty
Check the following before operation:
The infection (if present) must be under control
Control blood sugar
Preoperative x-rays should include the whole length of the leg including knee and ankle. The size of the nail should be the same width as the narrowest area of the medullary canal of the tibia. The length should be determined on the x-ray as well as on the patient, and the nail should be up to the proximal tibia.
Prophylactic antibiotics are mandatory and should cover both gram positive and negative organisms and given half an hour before operation.
Position of the Patient
The patient may be in supine or prone position depending on the surgical approach.
The soft tissue covering the ankle joint contains little or no fatty tissue, and often the soft tissue is abnormal because of previous trauma or surgery. The surgical approach should avoid undue tension on the skin. The cutaneous nerves are superficial and take care of these structures during operation.4
The approaches usually used are:
1. Anterior approach
2. Anterolateral approach
3. Transmalleolar approach
4. Posterior approach
The anterolateral approach gives excellent access to the ankle joint, talus, and most other tarsal bones and joints, and it avoids all important vessels and nerves. It permits excision of the entire talus (if needed), and the only tarsal joints that cannot be reached are those between the navicular and the second and first cuneiform bones.
The anterior approach gains access to the part of the ankle joint between the medial malleolus and the medial articular facet of the body of the talus, often it is difficult when fusing the ankle through the anterolateral approach. Usually the approach is developed between the extensor hallucis longus and extensor digitorum longus tendon.
The transmalleolar approach is not a popular method as it is possible to injure the tibial vessel and nerve.
Preparation of the Surfaces
The joint surfaces can be prepared for arthrodesis by simply denuding the remaining articular cartilage and “fish scaling” the subchondral bone with small gauge or osteotome. If shortening is greater than 1 cm then an iliac bone graft (tri-cortical) should be considered.
Insertion of the Nail
Once the arthrodesis site is prepared, place the patella straight up and position the ankle in neutral flexion. The heel must be in 5° of valgus and slight external rotation. Hold the foot on the tibia in proper position, place the guide through the heel pad in line with the center of tibia. Drive the guide into the center of medullary canal of the tibia (if possible under image intensifier).
In the sagittal plane, draw a line from the second toe to the center of the heel, and in the coronal plane, draw a line at the junction of anterior third and middle third of the heel pad. The intersection of these lines indicates the correct portal of entry for the nail.
Hold the ankle in the proper position and insert the nail into the calcaneus, re-evaluate the position of arthrodesis before driving the nail into the tibia. Before final hammering of the nail, place the bone graft in the sinus tarsi and fusion site. Impact the nail after insertion of the graft; the apex of the nail should be posterior. Locking screws are inserted from lateral to medial, and take care that the screws are properly placed in the calcaneus and talus.
Pressure bandaging is applied and the limb is elevated. After removing the stitches on 10th postoperative day, the posterior plaster slab is applied. The plaster slab is removed after 6 weeks starting with active mobilization and partial weight bearing. Full weight bearing starts after clinical and radiologic union (average 12–16 weeks).
The patient does not need to wear external devices but they will walk with a limp as the stride phase is reduced.
In the literature, it is reported that fusion in the hindfoot decreases mobility of the joints, and the degree of force dissipation is significantly altered. One study reported nondisplaced stress fracture around proximal interlocking screws. There can be risk of injury to vital structures, such as flexor hallucis longus.5,6
SIGN SURGERY IN MYANMAR
The SIGN project started in May, 2002 at Yangon General Hospital and later extended to North Okkalapa General hospital, Mandalay General Hospital, and Defense Services Orthopaedic Hospital. Between 2002 and December, 2008, a total of 1317 SIGN surgeries were done in Yangon General Hospital. Because Myanmar is a low-income country, there are many injuries to the skeletal system, and 20% of these are long bone fractures. SIGN nails proved to be a great benefit for our patients with tremendous outcomes.
Fifteen intra-articular fusions (tibio-talo-calcaneal) were done using SIGN IM nailing, and all healed well (mean union time, 16 weeks), except 1 Charcot joint that resulted in amputation. One superficial infection was reported, but no stress fracture was reported in an average of 18 months of follow-up (range, 12–32 weeks).
1. Mauldin DM, Asher MA (ed). Ankle and foot reconstruction. Orthopaedic Knowledge Update 1, Chicago, IL, AAos, 1984, Chapter 40, pp. 369–376.
2. Kitzoka HB. Arthrodesis of the ankle; techniques, complications and salvage treatment. Instr Course Lect
3. Barend MB, Glisson RR, Nunley TA. A biomechanical comparison of intramedullary nail and crossed lag screw fixation for tibiotalocalcaneal arhtrodesis. Foot Ankle Int
4. Canale ST, Beaty JH, eds. Surgical approaches. In: Campbell's Operative Orthopaedics
. 11th ed. Philadelphia, PA: Mosby Elsevier; 23.
5. Norman T, Pinzur M, Paximos O. Tibiotalocalcaneal arthordesis with retrograde intramedullary nail, a biomechanical analysis of the effect of nail length. Foot Ankle Int
6. Fleming SS, Moore TJ, Hutton WC. Biomechanical analysis of hind foot fixation using an intramedullary rod. J South Orthop Assoc