Posttraumatic Reconstruction of the Foot and Ankle

Analysis of the Problem

Posttraumatic deformity at the ankle is frequent and may result from a multitude of injuries, such as pilon fractures, malleolar fractures, talar body fractures, osteochondral fractures, and ligamentous injuries. Residuals of trauma are the leading cause of ankle arthrosis. The site and plane of the deformity must be identified, and one has to bear in mind that a combination of the following deformities is possible :

• Supramalleolar

• Transmalleolar (medial/lateral malleolus)

• Intraarticular (tibial plafond/anterior/posterior tibial rim)

• Talar body

Bony deformities are regularly combined with chronic instability of either the

• collateral (medial or lateral) ankle ligaments, or

• syndesmotic ligament complex.

Direct damage to the cartilage at the time of injury or secondary damage by eccentric loading due to extraarticular deformity, chronic instability, or intraarticular incongruity will rapidly lead to posttraumatic ankle arthritis .

Finally, an associated but unrecognized tubercle of Chaput fracture or lateral plafond impaction may lead to AVN of the lateral plafond.

Operative treatment for degenerative arthritis is usually considered when nonoperative treatment, such as shoe-wear modification, orthoses, and physical therapy, has failed over a minimum of 6 months. However, relevant posttraumatic malalignment should be corrected as early as it is detected to avoid the development or progression of arthritis at the ankle and adjacent joints.

In early arthritis with lateral ankle instability, an anterior osteophyte débridement and stabilization by the Brostrøm procedure or anatomic ligament reconstruction ( Fig. 68.7 ) is indicated. It is important that anterior débridement does not reduce the containment of the talar dome by débridement of the anterior malleolus beyond its original anatomy. Rather, grooving the talar neck is used to decompress the anterior joint. This, plus lengthening of the Achilles tendon or a tight gastrocnemius, will tend to decrease the chance that the foot will continue to extrude anteriorly.

Supramalleolar Osteotomy

Unicompartmental ankle arthrosis may be caused by long-term varus or valgus and subsequent eccentric loading in the ankle, similar to a long-term varus or valgus deformity in the knee. Ankle arthrosis caused by traumatic posterior tibial tendon rupture occurring with medial column collapse, valgus heel, and Achilles tendon or gastrocnemius contracture may require early midfoot reconstruction. Reconstruction should include heel-cord lengthening, posterior tibial augmentation, and possibly a medializing calcaneal osteotomy to realign and preserve the ankle. Medial column stabilization also may be needed to control the valgus attitude of the hindfoot. As the medial midfoot is primarily stability joints, a plantar medial closing wedge osteotomy can be the ideal treatment.

Pain in ankles with eccentric erosion, such as those in valgus or varus, may be temporized by an osteotomy in the supramalleolar area. Supramalleolar osteotomies are done when varus, valgus, or excessive ante- or recurvation is seen in the plafond.

If there is excessive heel valgus or varus, a medializing or lateralizing calcaneal osteotomy may be carried out. The calcaneal osteotomy may be the sole procedure if the plane of the plafond is correct or combined with a supramalleolar osteotomy in the case of a multilevel deformity. Both procedures may be done for arthrosis with unicompartmental erosion and can delay the need for arthrodesis or arthroplasty for several years. As a rule of thumb, at least 50% of the ankle joint surface should be preserved.

The supramalleolar osteotomy may be carried out as a closing or opening wedge ( Fig. 68.8 ). The latter is regularly preferred in the case of posttraumatic shortening of the distal tibia due to bone loss, impaction, or AVN, provided an adequate soft tissue cover. Potential disadvantages of an opening wedge osteotomy include the need for a bone graft with a longer time to healing and a higher risk of nonunion. A fibular osteotomy is added in any case of fibular deformity and correction of 10 degrees or more at the tibia. Alternative techniques include dome (crescentic) or oblique sliding osteotomies . Both have the potential to correct length and deformity without the need for bone grafting.

If a talar tilt is present, an oblique tibial osteotomy has the potential to both correct the supramalleolar varus deformity and narrow the ankle mortise to address ankle instability. This osteotomy is regularly combined with a lateral shift of the calcaneus and lateral ligament reconstruction after excision of submalleolar ossicles that are frequently present ( Fig. 68.9A ). In the case of excessive soft tissue scarring or critical soft tissue conditions, gradual correction can be achieved with a small-wire external fixator (Ilizarov or Hexapod) that may be applied in an ankle-sparing or ankle-spanning manner. If erosion of the medial plafond has led to an intraarticular deformity, the osteotomy can be directed to the intraarticular apex of the deformity ( plafondplasty ; see Fig. 68.9B ).

The surgical approach is dictated by preexisting scars and implants as well as by the direction, amount, and apex of the deformity. Typically, the distal tibia is addressed via an anteromedial approach, and the distal fibula is addressed via a lateral approach. The osteotomy is performed according to the preoperative planning, preferably at the level of the center of rotation and angulation (CORA) . However, in malunited pilon fractures, the CORA frequently lies close to or at the ankle joint. If a joint-preserving correction is planned, the osteotomy is performed more proximally. The exact site and angle of the osteotomy may be marked with Kirschner wires (K-wires), and the amount of correction may be verified with intraoperative fluoroscopy. Most authors recommend an overcorrection of 3 to 5 degrees in the coronal plane to achieve a lateral distal tibial angle between 93 and 95 degrees.

The tibial osteotomy is performed with an oscillating saw under continuous water irrigation. The osteotomy is stopped a few millimeters short of the opposite cortex to enhance the intrinsic stability of the osteotomy and prevent shifting of the distal fragment during deformity correction. For opening of the osteotomy, a laminar spreader is used. Osteotomy of the fibula is performed as indicated. The fibular osteotomy is done obliquely to increase the bony surface. Fixation is chosen according to the individual bone quality, the amount of bone grafting in opening wedge osteotomies, and the surgeon's preference. Tibial osteotomies are typically fixed with medial locking plates; fibular osteotomies are usually fixed with a one-third tubular plate.

Substantial improvement in both pain and function has been reported in the literature, with an average improvement in the American Orthopaedic Foot and Ankle Society (AOFAS) ankle–hindfoot score of 33 points out of a total of 100. Osteotomies for varus ankle arthritis have been shown to delay the originally planned ankle arthrodesis or total ankle replacement (TAR) in more than 90% of patients. Risk factors for failure are advanced stages of ankle arthritis, ankle instability, and joint incongruency.

Malleolar Osteotomies

The pathologic anatomy of malleolar malunions follows directly from the initial trauma mechanism and the resulting bony and ligamentous lesions. The typical posttraumatic deformity after inadequate treatment of a seemingly “simple” ankle fracture consists of shortening of the fibula that is regularly accompanied by lateral shift and external rotation. With a malunited medial malleolus or deltoid ligament instability, the talus follows the displaced fibula, resulting in a lateral shift, lateral tilt, and external rotation. This deformity can be combined with a malunion of the posterior tibial rim (or third malleolus) and the anterior tibial tubercle (Chaput). In the presence of syndesmotic instability, there is a manifest widening of the ankle mortise and the tibiofibular clear space (TCS).

Less frequently, but with the same consequences, malunited supination-adduction fractures will lead to shortening of the medial malleolus due to a malunion of the typically vertical fracture and medial shift and tilting of the talus. There is either lateral ligament instability or a malunited inframalleolar fibular fracture. Both adduction and abduction fractures can lead to partial impaction of the medial or lateral tibial plafond, respectively. Particularly in the lateral plafond, AVN can result from high-energy trauma, open fractures, extensive stripping of periosteum, or a missing lateral branch of the anterior tibial artery.

According to clinical and biomechanical studies, any fibular shortening or translation of 2 mm or more is associated with a significant load shift within the ankle joint and therefore an increased risk of posttraumatic arthritis. Symptomatic malunions of 2 mm or more should therefore be corrected. The impact of malrotation is less clear from clinical studies. In a biomechanical experiment, 5 degrees of fibular rotation resulted in a weight shift at the ankle joint, whereas in a clinical study, up to 15 degrees was still tolerated by the patients.

The fibular osteotomy is primarily aimed at lengthening the shortened fibula. At the same time, any valgus or rotational deformity is corrected. A lateral approach is used, and the superficial peroneal nerve has to be protected in the proximal part. For shortening of up to 5 mm, an oblique or Z-shaped osteotomy without bone grafting is usually sufficient, whereas more lengthening requires a transverse osteotomy with corticocancellous bone graft from the tibia or iliac crest ( Fig. 68.10A ). A stable, straight plate is first fixed to the distal fragment. With a screw placed above the plate and insertion of a laminar spreader or plate tensioner, the correct fibular length is then obtained, and the plate is fixed proximally. Residual valgus is corrected by the application of a straight plate, and the talus is shifted medially while following the corrected fibula. To achieve correction of the talar position, any medial malleolar malunion has to be corrected simultaneously, and intervening scar tissue between the medial malleolus and the talus has to be removed. By lengthening and medial shift of the distal fibula, malrotation of the distal fragment will correct by sliding along the lateral talar facet with the foot in neutral position.

Medial malleolar malunions are frequently combined with malunions of the fibula and posterior tibia. The medial malleolus is osteotomized along the former fracture, resulting in an oblique osteotomy aimed toward the medial edge of the ankle joint in the case of a malunited pronation/external rotation fracture. Care is taken not to injure the posterior tibial tendon and tibial neurovascular bundle. In the case of a malunited supination fracture, a lengthening osteotomy of the medial malleolus is carried out that follows the more vertical former fracture. To allow restoration of the ankle mortise, any accompanying varus deformity of the distal fibula has to be corrected simultaneously. Impaction of the medial plafond is corrected with subcortical osteotomy and bone grafting. Symptomatic nonunions of the medial malleolus are treated with débridement, cancellous bone grafting, and bone dowels that are inserted press-fit into the former screw holes. Internal fixation is mostly achieved with a medial plate.

Malunions and nonunions of the anterior and posterior tibial fragment are treated with corrective osteotomies or débridement with bone grafting along the former fracture line and are fixed with screws or small plates. Malunited posterior fragments can be addressed either through the fibular osteotomy or via separate posterolateral (or posteromedial) approaches. The anterior tibial tubercle (Chaput) can be corrected via the existing lateral approach to the distal fibula or a small, separate anterolateral approach.

Because both the anterior and posterior tibial tubercle carry the respective tibiofibular (syndesmotic) ligaments, the correction of bony malunions will also restore syndesmotic stability in many cases. The same is true for fibular lengthening that will stretch out the scarred syndesmotic ligaments. Similar to acute fracture treatment, syndesmotic stability should be tested after completing the bony corrections. In the case of residual instability, syndesmotic stabilization should be carried out after local revision with syndesmotic screws, flexible implants (suture button), or ligamentoplasty (see Fig. 68.10B ) or as a salvage procedure by tibiofibular fusion.

The results of corrective malleolar osteotomies are well documented for fibular lengthening. The overall functional results with up to 27 years of follow-up are good to excellent, with patient satisfaction in 75% to 85% and secondary ankle fusions in less than 15% despite radiographic progression of arthritis in about 50% of cases. A few authors also report on favorable results after corrections of nonunions of the lateral and medial malleolus or the posterior tibial fragment.

Intraarticular Osteotomies

Intraarticular malunions at the ankle result from fractures of the tibial pilon or trimalleolar fractures with displaced posterior fragments (“posterior pilon variant”). Partial impaction of the medial or lateral tibial plafond can result from forced adduction or abduction, respectively, at the time of injury and may be missed on initial presentation. Typically, these injuries resulting from axial forces produce considerable primary cartilage damage, and residual intraarticular malunions rapidly progress to posttraumatic ankle arthritis. The vast majority will need corrective ankle fusion as a salvage procedure. Joint-preserving correction with secondary anatomic reconstruction for intraarticular malunions is possible only in carefully selected patients with largely intact cartilage, sufficient bone quality, residual function, and good compliance. Corrective osteotomies with secondary joint reconstruction may be contemplated in relatively simple intraarticular malunions.

Preoperative CT scanning is needed to determine the position and amount of incongruities in the joint surface; the exact planes for osteotomy along solidly malunited fractures; and the amount of fibrous nonunion, sclerotic, or necrotic bone requiring débridement and bone grafting. Correction is performed according to the individual pattern of malunion. Approaches and reconstruction follow the principles of primary open reduction and internal fixation of pilon fractures . If possible, existing scars from previous surgery are used, especially if surgical implants have to be removed before correction.

Malunions of the posterior tibial plafond (posterior pilon) are addressed via a posterior approach with the patient prone. Under lateral fluoroscopic projection, the fracture line is marked with two K-wires, and the osteotomy is performed toward the articular step-off with a chisel. Alternatively, a transfibular approach is used ( Fig. 68.11 ). In addition to intraarticular malunions due to residual steps and gaps, malunion or nonunion at the metaphyseal area after comminuted pilon fractures results in supramalleolar axial deviation . These deformities have to be addressed simultaneously during corrective surgery, as detailed previously.

Although early attempts at joint-preserving corrective surgery for malunited pilon fractures were fraught with an unacceptable 80% failure rate, a recent series from two centers reported good to excellent clinical results in 10 of 14 patients (71%) followed for an average of 5 years after corrective intraarticular osteotomy. Late bone grafting was needed for nonunion in one case and AVN of the medial tibial metaphysis in another case; both healed uneventfully in the further course. At 5 years’ follow-up, radiographic signs of posttraumatic arthritis were noted in all cases, but only two patients (14%) needed a late ankle fusion for symptomatic arthritis at 2 and 2.5 years after correction. In the case of progressive ankle arthritis despite corrective osteotomy, ankle fusion (or replacement) may be carried out as a secondary procedure on a well-aligned ankle.

Arthrodesis Versus Ankle Arthroplasty

Ankle arthrodesis has long been the gold standard for ankle salvage (see Videos 68.1 and 68.2 ). After the poor performance of first-generation implants, ankle arthroplasty has emerged as a viable alternative to fusion over the past 20 years. The indications for both methods do not overlap completely because there are some absolute and relative contraindications to ankle arthroplasty, although some of these are debated, and there seems to be no clear cutoff for several of these parameters. An ideal patient for ankle arthroplasty is one with low demand and older age, good bone stock, good alignment and muscle balance, strong collateral ankle ligaments, reasonable ROM, and an adequate ratio of bone size to body weight. Furthermore, arthroplasty requires a compliant patient who does not smoke and will not bear weight prematurely or with excessive impact or shear force in the 6 or 8 weeks needed for implant bonding. Needless to say, these are also good preconditions for ankle arthrodesis.

When fusion fails from a poor alignment in equinus, anterior extrusion, or varus, it can be revised by corrective osteotomy and repositioning. Exceptionally, an ankle fusion can be taken down and changed to an arthroplasty if adequate anatomy, including both malleoli and the deltoid ligament, was left intact during the original fusion. However, only a few reports and no long-term results are available on these techniques.

The biggest concern with ankle arthrodesis is the development of adjacent joint arthrosis, with most being secondary subtalar arthrosis. Long-term studies have revealed up to 100% adjacent joint arthritis in radiographic images at 20 years’ follow-up; however, not all become symptomatic, and the reported rates of secondary subtalar fusion are below 10%. All of these studies, however, included a substantial portion of ankles that were fused in either varus/valgus or equinus. On the other hand, a high percentage (up to 96%) of subtalar and midfoot arthritis has been shown to be preexisting due to ankle malfunction in end-stage arthritis. Other issues with ankle arthrodesis include nonunion and infection. With the present-day open or arthroscopic screw fixation techniques, the rates of these complications are in the range of 0% to 12%. Higher rates of both nonunion and infection are reported after arthrodesis under critical conditions such as lingering infection, previous failed total ankle arthroplasty or fusion, Charcot neuropathy, heavy smokers, and noncompliant patients.

Component loosening continues to be the biggest concern in the failure of the tibial or talar component bonding and subsequent bony overgrowth around this component. Eventually, subsidence or migration in various directions occurs. The 10-year survival rates of total ankle arthroplasty in the available literature range from 71% in pooled analyses to 75% in register studies and up to 94% in single-center studies by the designers of the prosthesis. Thus they still fall considerably short of the rates for total hip or knee arthroplasty.

If sufficient bone stock is preserved, revision arthroplasty may be attempted with several of the available prosthesis models. For the Agility ankle prosthesis, a custom-stemmed talar component may be used to salvage talar subsidence. Although it sacrifices the subtalar joint, in these cases, the revision ankle can be easier to do and is markedly more successful than the primary ankle prosthesis with this model.

Other reasons for revisions after total ankle arthroplasty include medial or lateral impingement, bony overgrowth with loss of motion, and failure of the mobile bearing. Overall, revision rates after ankle replacement approach 50% within 10 years. The bottom line is that there is no permanent or even long-term answer to severe ankle arthrosis in young patients. Thus every effort should be made to achieve anatomic reduction and stable fixation in ankle fractures and fracture-dislocations and to exploit the possibility of joint-preserving osteotomies whenever possible, as detailed previously ( Video 68.3 ). Parameters in favor of arthrodesis and arthroplasty are summarized in Table 68.3 .

Arthrodesis Techniques

The goal of ankle fusion is to realign any posttraumatic deformity and to generate early union with minimal damage to the bone stock. The malleoli may be narrowed slightly, but there is no reason to remove them. When the malleoli are left intact, the normal anatomy is preserved, and the sheaths through which the posterior tibial tendon and the peroneal tendons pass are retained.

The transfibular arthrodesis technique proposed by Hansen is preferred when the talus is in a nonanatomic position, particularly anterior subluxation. Through a longitudinal incision, the fibula is laterally and anteriorly freed up by transecting the anterior syndesmosis and the anterior talofibular ligament ( Fig. 68.12 ). An osteotomy is carried out approximately 3 inches above the tip of the fibula in an oblique plane going from proximal lateral to distal medial. Unless the fibula has already been shortened, it is slightly shortened by making a second cut and removing 5 to 10 mm of bone. The fibula is sheath-hinged to expose the ankle and subtalar joints laterally.

A small anteromedial vertical incision is made just in front of the medial gutter to clear cartilage from the medial talus and the medial malleolus and to push the talus against the medial malleolus.

After the joint has been denuded, shaped, and drilled, the talus with the foot is placed into ideal position (5 to 7 degrees of valgus and 0 degrees of equinus), and temporary fixation with a K-wire is applied. Correct ankle position is verified with anterior-posterior and lateral fluoroscopic views. If the alignment is satisfactory, the first fixation screw is placed by direct vision through a stab wound just lateral to the heel cord, well proximal to the ankle. A 4.5-mm drill is inserted into the posterolateral tibia high on the posterior malleolus approximately 3 cm above the ankle. It is directed downward and slightly medially and aimed to cross the anterior half of the ankle joint first, then to enter the neck and continue into the lower head of the talus. A 4.5-mm drill is used in the tibia, and a long 3.5-mm drill is used into the talus. A 6.5-mm screw that is approximately 75 mm long with 16 mm of thread is appropriate in most patients. Alternatively, a cannulated screw of similar size may be used.

Next, a 6.5-mm screw of appropriate length is placed from the upper medial malleolus and aimed at a 45-degree angle into the midbody of the talus. Another screw is placed from the anterior tibia down into the posterior talus, with care taken not to penetrate the subtalar joint. After the medial cortex of the osteotomized fibula has been denuded, it is placed back against the lateral talus and the distal tibia at appropriate length and position and fixed there with 3.5- or 4.0-mm cortical screws. The angled proximal end of the distal fibular fragment traps the fibula from above and will not protrude under the skin because that area has been beveled.

Any bone that has been removed, particularly osteophytes, can be used as a graft between the anterior fibula and the tibia. Approximately two shear-strain–relieved graft sites, each approximately 1 cm in diameter, are burred into the anterior joint and filled with cancellous autograft from the proximal anterior tibia (Gerdy tubercle) site. Fluoroscopic views are taken before closure to check ankle position and screw length.

Postoperatively, the foot is casted for 2 to 3 weeks, after which the cast is exchanged for a commercial walking boot with a rocker sole. The patient is limited to weight-of-leg or slightly more weight bearing and may remove the boot for bathing, sleeping, and mobilizing the subtalar joint. Healing usually takes place in 8 to 12 weeks, and the patient continues to wear a shoe with mild rocker modification in the sole indefinitely.

The four-screw technique, described by Zwipp, uses an anterior approach ( Fig. 68.13 ). Preparation and positioning are similar to the first technique described—that is, the foot is brought into neutral flexion-extension and slight valgus with the dome of the talus at the midaxial line of the tibia. Correction of malalignment is achieved either with asymmetric resection of the distal tibia and talus or with interposition bone grafting in the case of bone defects and relevant shortening. Two 6.5-mm lag screws are placed side by side from the well-exposed distal anterior tibia, starting at least 3 cm proximal to the joint and going into the midbody of the talus. The all-important third screw is inserted through a stab wound made over the posteromedial crest of the tibia above the medial malleolus and drilled anterolaterally into the neck and inferior head of the talus. The fourth screw is inserted percutaneously from the fibula into the talus.

In the case of marked syndesmotic instability, the tibiofibular syndesmosis is also denuded and grafted, then stabilized with a fifth 6.5-mm screw placed from the fibula to the tibia. If the fibula has to be shortened to avoid fibulocalcaneal impingement, a shortening supramalleolar osteotomy is carried out similar to the first technique

Postoperative management is similar to the previous technique using a special boot with a flexible sole after wound healing and allowing early full weight bearing in the boot in the case of absence of pain. Theoretically, with this technique, a later arthroplasty can be done through the same incision, and the screws, which will have to be removed, are easily accessible through the standard anterior approach.

Total Ankle Arthroplasty Techniques

Various types of ankle arthroplasties are used worldwide, and several new prostheses were introduced in the past few years. A detailed description would be beyond the scope of this chapter. It is clear that the need for proper muscle balancing, proper alignment, and proper insertion will still be uppermost in importance. Current prostheses have a three-component design (mobile bearing), require minimal bone resection, and allow exchange/revision of the individual components. The technique used for arthroplasty is quite demanding, and surgeon experience is an important factor. As with ankle fusion, correct alignment of the ankle and hindfoot is indispensable for good function. Any accompanying ankle and hindfoot deformities or instabilities have to be addressed either during TAR or in staged procedures.

By far, the most difficult ankles to treat by arthroplasty are those with residual varus problems. These require a number of specialized muscle and ligament balancing procedures in addition to bony realignment. Usually, transfer of the peroneus longus tendon to the 5th metatarsal base or into the peroneus brevis tendon (if intact) is added for cavovarus deformity. A lengthening osteotomy of the medial malleolus or a lateralizing calcaneus osteotomy may be added. Significant subtalar and/or talonavicular arthritis may require an additional fusion of the affected joint(s), either simultaneously or as a separate procedure. Experience with numerous cases is essential because almost every case has unique features that must be recognized and definitively treated.

Analysis of the Problem

The talus has unique anatomy, with two-thirds of its surface being covered by cartilage and the absence of direct muscular attachments. As a “bony meniscus” between the lower leg and foot, it contributes to three essential joints: the ankle, subtalar, and talonavicular joints. The integrity of the talus and its joints therefore is essential for global foot function, and malunions of the talus are debilitating conditions for the affected patients.

Malalignment of the talus most frequently results from inadequate fracture reduction or fixation. Nonoperative treatment for displaced talar neck fractures will lead to a symptomatic malunion in about half of the cases. Nonunion of the talar neck or body is seen in less than 10% in most series. It regularly results from an inadequate fixation with residual instability. Fractures of the lateral and posterior processes are frequently overlooked at first presentation and may rapidly lead to symptomatic arthritis of the subtalar joint. Malaligned, bony fragments or osteophytes will also frequently lead to impingement of the posterior tibial tendons and tarsal tunnel or sinus tarsi syndrome.

Residual intraarticular step-offs and direct chondrocyte damage due to the impact during the initial injury will invariably contribute to arthritis development. The rates of posttraumatic arthritis after talar neck and body fractures provided in the literature vary considerably from 16% to 100% and appear to increase over time. However, only about one-third of patients with radiographic signs of arthritis eventually become clinically symptomatic, with the need for an arthrodesis ranging between 0% and 33% of cases.

AVN of the talar body is a specific complication after talar neck and body fractures. The prevalence of AVN increases with initial displacement. Posttraumatic AVN tends to be irregular and incomplete when compared with AVN caused by the use of corticosteroids or other drugs. For planning corrective procedures, it is important to distinguish between partial AVN and total AVN with the collapse of the talar dome. With only partial AVN, creeping substitution will gradually replace the necrotic areas.

With respect to union, AVN, and infection, an easy-to-use classification of posttraumatic talar deformities ( Table 68.4 ) can be applied that is helpful for planning correction. The final decision on joint-preserving reconstruction versus arthrodesis is often based on the quality of the cartilage at the time of surgery.

Malunions and nonunions of the lateral or posterior talar process can be salvaged at an early stage by complete excision of the malunited fragments. In the presence of symptomatic arthritis, in situ fusion of the subtalar joint may become necessary.

Techniques of Joint-Preserving Corrections

Like with acute fracture treatment, the key to correction of many problems in the talus is adequate surgical exposure, which typically requires two approaches. Preexisting incision scars from previous surgery are only used if deemed adequate. It is important not to disturb the neurovascular supply located at its posteromedial corner and through the deltoid ligament.

For access to the talar neck, the patient is placed in a supine position, and simultaneous anteromedial and anterolateral incisions is recommended. For exposure of the talar body, a transmalleolar (medial) approach through an extended medial utility incision is preferred over dissection of the deltoid ligament that carries the blood supply to the talar body. An approach to the lateral body may entail a single or double osteotomy of the fibula. For the posteromedial corner fragments, an inferomedial approach may be used, which, in fact, is the upper end of a medial utility incision and allows access to the talus between the posterior tibial and flexor digitorum longus tendons and neurovascular structures. To approach the os trigonum and the posterior aspect of the talus and posterior degenerative spurs, a vertical posteromedial incision parallel to the heel cord is useful, which is best achieved with the patient in prone position. After entering the deep posterior compartment fascia, the sheath of the flexor hallucis longus can be loosened and the tendon pulled medially along with the neurovascular structures to provide excellent exposure of the posterior talus, ankle, and subtalar joints. A straight vertical posterolateral approach, with care taken around the sural nerve, provides probably the most complete exposure of the posterior ankle, talus, and subtalar joints. This approach requires the patient to be positioned prone or laterally.

For malunited or nonunited lateral process fractures of the talus, repair is done through a short Ducroquet-Ollier approach . This oblique surgical approach is made along the skin line and can be placed directly over the sinus tarsi. The proximal end of the extensor digitorum brevis is lifted off the anterior calcaneus, with the removal of some fat, scar tissue, and possibly part of the cervical ligament from the sinus tarsi. Débridement of any prominence or excrescence and particularly malunited lateral talar process fractures can then be done as needed. Again, care is taken to avoid going in too proximal using this approach and risking division of the anterior talofibular ligament and damage to the intermediate dorsal cutaneous nerve, a branch of the superficial peroneal nerve.

After adequate exposure, the original fracture lines, as assessed with preoperative CT scanning ( Fig. 68.14 ), are re-created stepwise and carefully with small osteotomes in cases of solid malunion (type I deformity) . Manifest nonunions (type II) are treated with complete resection of the fibrous pseudoarthrosis and underlying sclerotic bone until viable cancellous bone becomes visible. The resulting defect is then filled with bone graft to avoid shortening or axial deviation. Avascular areas of the talar body in type III deformities may be dealt by with curettage and subchondral drilling to enhance bone regeneration.

The fragments are mobilized and carefully manipulated with K-wires used as joysticks rather than direct clamping to avoid damage to the joint surfaces or further fragmentation. Anatomic realignment of the talar neck, the ankle joint, and subtalar joint is assessed visually through the bilateral approaches and fluoroscopically. Posttraumatic varus deformity of the talar neck is corrected with a structural tricortical autograft or allograft introduced from the medial aspect. Definite fixation is typically achieved with small fragment screws and/or plates. The latter is used to bridge a former comminution zone or stabilize a rather small talar head fragment. Care must be taken to avoid joint irritation with either implant.

Postoperative treatment consists of early motion of the ankle, subtalar, and midtarsal joints to regain as much function as possible. Patients are typically mobilized with partial weight bearing of 15 to 20 kg for 10 to 12 weeks postoperatively. The presence of a preexisting partial AVN should not prolong the period of partial weight bearing and does not appear to influence the functional result of corrective surgery. In a series of 25 joint-preserving corrections, we have observed neither development nor progression of AVN. In 13 of 21 patients (62%) who were followed for a mean of 5.4 years, mild progression of arthritis has been noted. However, late fusion of the ankle, subtalar, or talonavicular joint was necessary in only 4 of 25 patients (16%) between 1.5 and 8 years after correction. The mean AOFAS score increased from 36.6 preoperatively to 88.7 at the latest follow-up.

Salvage Options

In the majority of talar malunions or nonunions, manifest posttraumatic arthritis, considerable bone loss, total AVN of the talar body, or a combination of these findings will prevent joint preservation. For these patients, axial realignment of the hindfoot in combination with arthrodesis of the affected joint(s) remains a viable salvage option (Video 64.4). If both the ankle and subtalar joints need to be fused, every effort should be made to preserve the talar head and the talonavicular joint as part of the coxa pedis. Total ankle replacement is a viable treatment option for posttraumatic ankle arthritis if the bone stock of the tibia and talus is still largely preserved and no gross deformity is present. It should be considered, in particular, if the subtalar and talonavicular joints are arthritic and have to be fused to avoid a pantalar fusion and thus a totally stiff ankle and hindfoot. For the particular techniques of ankle replacement and ankle and subtalar arthrodesis, the reader is referred to the pertinent sections of this chapter.

Extensive AVN with the collapse of the talar body, as in a type IV deformity , will eventually lead to a collapse of the talar dome, with loss of height and axial malalignment at the hindfoot and midfoot. To achieve a successful union, removal of all necrotic bone is mandatory. Total talectomy and the introduction of a large bone block do not appear to result in higher fusion rates than fusion around the remaining body after excision of all necrotic tissue. Tibiotalocalcaneal or tibiocalcaneal arthrodesis is then obtained with screws, plates, or a locked retrograde intramedullary nail. The latter appears to be the most stable fixation under these conditions ( Fig. 68.15 ).

The most severe posttraumatic condition after talar fracture is osteomyelitis or septic AVN (type V deformity) . Infection requires aggressive débridement, frequently resulting in subtotal or total talectomy , temporary external fixation, and implantation of local antibiotic beads. Fusion is then performed as a staged procedure after the infection has resolved, typically with bone grafting, screws, plates, a retrograde intramedullary nail, or an Ilizarov frame. Excessive loss of height in the case of tibiocalcaneal arthrodesis can be avoided by corticocancellous bone graft or sliding a portion from the anterior tibia distally into the defect (Blair fusion). If the talar head can be preserved, it is fused to the anterior aspect of the tibia or bulk bone graft (e.g. femoral head allograft) to maintain residual motion through the talonavicular joint.

Aftercare is tailored individually to the bone quality and the amount of bone grafting required. Usually, partial weight bearing with 15 to 20 kg is maintained for 6 to 12 weeks postoperatively in a lower leg cast or special arthrodesis boot. Physical therapy is aimed at compensatory ROM through the remaining joints. With proper realignment and aftercare, corrective arthrodesis regularly leads to significant functional rehabilitation of patients with talar malunion.

Analysis of the Problem

Nonoperative treatment and inadequate reduction of displaced calcaneal fractures regularly result in painful malunion or nonunion, with numerous complications resulting from the pathomechanics of the original injury. Residual articular incongruity rapidly leads to arthritis, predominantly of the subtalar joints. Hindfoot malalignment results from displacement of the calcaneal tuberosity after extra- and intraarticular fractures, typically in varus and shortening. The original fracture mechanism with axial impaction of the talus into the calcaneal body leads to a loss of calcaneal height, leading to anterior ankle impingement because of talar inclination, and heel widening with bulging of the lateral wall, resulting in lateral subfibular abutment and peroneal tendon impingement. With severe deformity, the talus loses its support from below and tilts in the ankle mortise.

Calcaneal fracture-dislocations with lateral and upward displacement of the whole tuberosity produce chronic peroneal tendon dislocation and sometimes an irregular, plastic deformity of the distal fibula from direct impaction. All these conditions severely affect the function of the ankle, subtalar, and calcaneocuboid joints, resulting in conflicts with shoe wear and an altered gait pattern, most notably on uneven ground. These patients regularly report on disabling pain at the tip of the lateral malleolus. On clinical examination, they are also tender to palpation over the sinus tarsi and along the course of the peroneal tendons.

Planning Correction

As with all posttraumatic foot and ankle deformities, treatment of calcaneal malunions is tailored individually to the specific sequelae of the original fracture and the patient's functional demands, compliance, and comorbidities. Stephens and Sanders were the first to develop a classification system and treatment protocol for calcaneal malunions based on CT scans. More recently, Zwipp and Rammelt have developed a classification system to address all types of calcaneal deformities, as described previously ( Table 68.5 ). A synopsis of both classifications is provided in ( Fig. 68.16 ).

Surgical Approaches

The extensile lateral incision commonly used for open reduction and internal fixation (ORIF) of the calcaneus also works well for reconstruction if a lateral plate has to be removed first. However, in the absence of a lateral plate and for other procedures, such as medializing or lateralizing osteotomies perpendicular to the tuber, other incisions are smaller and safer. For the latter, a small lateral oblique incision over the tuber is satisfactory. A short Ducroquet–Ollier approach is sufficient for correcting types I and II. For type III, aiming for subtalar fusion with bone-block distraction, a long vertical posterolateral (Gallie) incision is used. For correction of type IV, an oblique lateral (dislocation approach) and sometimes a medial modified McReynolds approach may be necessary. For type V, a bilateral and a third anterior approach to the ankle joint is necessary.

Joint-Preserving Corrections

Extraarticular malunions and selected intraarticular malunions with still-viable cartilage (Zwipp and Rammelt type 0) may be treated with joint-sparing corrective osteotomies and secondary internal fixation.

Extraarticular malunions frequently result from cranial displacement of fractures of the tuberosity behind the posterior facet of the subtalar joint (beak fractures). Other common findings after nonoperatively treated calcaneus fracture include a tuber that is tilted into varus but displaced laterally and a heel that is shortened in terms of lateral column length and vertical height. All these abnormalities can be corrected by an oblique osteotomy started more anteriorly on the lateral side of the heel and angled posteriorly and medially ( Fig. 68.17 ). Usually, the obliquity is located closer to the frontal plane than to the sagittal plane, and in this case, the amount of valgus that is corrected is greater than the amount of lengthening of the lateral column that occurs. In solidly malunited beak fractures, a posterior sliding closing-wedge osteotomy is needed to bring the superior tuberosity down. The local soft tissues are carefully stretched, without damage inflicted to the nerves or blood supply going to the bony fragments. The Achilles tendon should be lengthened to counteract the deforming force. The tuberosity is then gradually shifted plantarly, and any varus/valgus is corrected. Rotation is simple when the osteotomy is transverse but becomes quite complex when the osteotomy is made oblique to the frontal plane. Fixation is achieved with partially threaded large-fragment cancellous screws perpendicular to the osteotomy plane.

Intraarticular malunions that can be reconstructed (see Tables 68.2 and 68.5 ) require a surgical approach similar to that used for a calcaneus fracture. For the classical joint-depression or tongue-type fractures, this is mostly an extensile lateral approach with the patient positioned on the uninjured side. Any remaining implants introduced from lateral are removed. The subtalar joint is carefully freed from fibrous adhesions and lateral osteophytes. The cartilage status is assessed with direct probing. The osteotomy is performed stepwise with small chisels along the former fracture as analyzed with the preoperative CT scans. This typically requires an osteotomy at the angle of Gissane, a second one behind the posterior facet, and a third osteotomy below the depressed lateral joint fragment, connecting the other two. The joint-bearing fragment is then derotated and elevated to the posterior facet of the talus that is used as a template. Internal fixation is achieved with a lateral plate used for fracture fixation. The subthalamic bone defect is filled with either local bone graft or a corticocancellous graft from the anterior or posterior iliac crest.

Malunited simple Sanders type 2 fracture malunions may alternatively be corrected via a small sinus tarsi approach with direct control of joint reduction and percutaneous manipulation of the osteotomized main fragments ( Fig. 68.18 ). Lateral bulging and osteophyte formation (Stephens and Sanders type 1 malunion) can be addressed with decompression of the lateral calcaneal wall and peroneal tenolysis. Lateral wall exostectomy starts posteriorly, and the osteotome or oscillating saw is directed slightly medially relative to the longitudinal axis of the calcaneus to release subfibular impingement.

Malunited calcaneal fracture-dislocations with still-intact cartilage over the posterior facet of the subtalar joint are subject to corrective osteotomy and three-dimensional realignment, including a medial and plantar shift of the displaced calcaneal body with screw fixation to the sustentaculum fragment that is still in place, peroneal tendon rerouting behind the lateral malleolus, and suture of the superior peroneal retinaculum. The technique of the osteotomy is essentially the same as that described for the type IV malunions in the following section (see Fig. 68.23 ). The surgeon must be careful to avoid the neurovascular structures, particularly the lateral plantar nerve when it is entrapped in the scar. This nerve runs close to the medial calcaneus in the area of the usual osteotomy and is sandwiched between the quadratus plantae and the flexor digitorum brevis, which may be damaged by fracture and scarring down the nerve. The nerve can be damaged easily by pinching or stretching, and it can be inadvertently cut by an osteotome. When possible nerve damage is anticipated, it may be prudent to add a medial approach, similar to that used for a tarsal tunnel release, to protect the neurovascular structures by direct observation and mobilization. In addition, the medial extension of the former fracture creates a deep groove that can be easily found and used for the osteotomy.

Correction With Arthrodesis of the Subtalar Joint