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A malunited fracture is one that has healed with the fragments in a nonanatomic position. Whether the deformity is unsightly or not it can impair function in several ways: (1) an abnormal joint surface can cause irregular weight transfer and arthritis of the joint, especially in the lower extremities; (2) rotation or angulation of the fragments can interfere with proper balance or gait in the lower extremities or positioning of the upper extremities; (3) overriding of fragments or bone loss can result in perceptible shortening; and (4) the movements of neighboring joints can be blocked. Malunions, by strict definition, commonly are the rule in the closed treatment of fractures; however, they frequently are compatible with function. A malunited fracture becomes surgically significant only when it impairs function.
Malunions generally are caused by either inaccurate reduction or ineffective immobilization during healing. Most malunions could be prevented by skillful treatment of fresh fractures; however, malunion sometimes occurs despite the most expert treatment. Malunion may develop in patients with multiple trauma in whom treatment of more life-threatening injuries takes precedence. Especially in patients with head injuries, displacement can occur later and result in deformity and disability after the patient regains mobility.
When treating malunions, the following facts must be considered. Of the four characteristics that determine the acceptability of fracture reduction, the first in importance is alignment, the second is rotation, the third is restoration of normal length, and the fourth and least important is the actual position of the fragments. A slight deformity can be seriously disabling when a malunion involves a joint or is near one. If malunion causes only slight disability, function sometimes cannot be improved enough to justify surgery; however, a rotational deformity can be so disabling that surgery is required. Deformity of axial alignment in children younger than 9 years old may correct spontaneously with growth, especially if it is near a joint and in the plane of its motion. An offset in an epiphysis usually also corrects itself spontaneously in a child if the physis has not been injured.
Analysis of the deformity should take into consideration that most deformities can be resolved into one plane with regard to anteroposterior and varus or valgus deformity. Ries and O’Neill developed a trigonometric analysis of deformity and designed a graph to determine the true maximal deformity on the basis of the true anteroposterior and lateral radiographic views ( Fig. 58.1 ). Other trigonometric analyses of angulation osteotomies also have been reported.
The objective of surgery for malunion is to restore function. Although improving the appearance of the part may be equally important to the patient, surgery rarely is justified for cosmetic reasons alone. Operative treatment of malunion of most fractures should not be considered until 6 to 12 months after the fracture has occurred. In intraarticular fractures, surgery may be required sooner if satisfactory function is to be restored. When considering surgery, the degree of osteoporosis and soft-tissue atrophy must be evaluated, and a decision must be made whether early surgery would be preferable to active rehabilitation of the part followed by the surgery. Corrective surgery at the site of malunion is not always feasible. In some instances, a compensatory procedure may be necessary to restore function; in others, pain may be the predominant symptom and may require fusion of a joint.
Ilizarov pioneered work on intercalary limb regeneration with the use of circular external fixation techniques and various hinged constructs. These developments make possible the simultaneous restoration of alignment, rotation, and length. These techniques require a thorough understanding of frame design and construction, intensive patient counseling, and intensive physical therapy. Impressive results have been reported in some of the most challenging situations, especially infected nonunions and bone loss problems. Circular fixation techniques have a definite role in malunion surgery for the restoration of length and when previous infection has made conventional open reduction techniques inappropriate. Detailed instruction and experience with these techniques are necessary, however, before they can be used for reconstruction of complex malunions. Three-dimensional modeling can be useful in preoperative planning for various bone and joint malunions.
Malunion of fractures of the phalanges of the toes rarely causes enough disability to justify surgery. A deformity that causes pain can be corrected easily, however, through a lateral or dorsal incision that does not injure the tendons. Osteotomy and alignment of the fragments may be sufficient. For complete correction, however, wide resection may be required; this can be done with impunity because skillful movements of the toes are not needed.
If malunion of the neck or shaft of a metatarsal is disabling, the fragments almost always are angulated toward the plantar surface of the foot, producing an osseous mass on the sole; if the fracture was severely comminuted, the mass may simulate a tumor. Surgery should not aim to restore perfect apposition and alignment but only to correct angulation so that weight bearing does not cause painful pressure on the sole of the foot.
Make an incision on the dorsum of the forefoot parallel with the shaft of the affected bones; often one skin incision provides access to two bones.
Expose the old fractures and divide them with a small osteotome. In some instances, a wedge of bone must be removed to permit elevation of the fragments, but resection must not be extensive enough to result in nonunion.
Raise the fragments into a slightly overcorrected position by pressing from below and forcibly flexing the toes.
Fix the fragments with an intramedullary pin as described for fresh fractures (see Chapter 89 ).
A cast is applied from the tibial tuberosity to the toes; the bottom of the cast should be well molded to maintain the overcorrected position. At 3 weeks, any intramedullary pin or pins and the cast are removed and a walking boot cast is applied; a felt pad is inserted beneath the fractures to hold the toes in plantarflexion. At 6 weeks, the cast is replaced by a sturdy shoe fitted with an arch support and metatarsal pad.
Malunion of the tarsals except the talus and calcaneus can be discussed together. Because most fractures in this region are caused by violent trauma, several bones may be involved and perhaps severely comminuted and one or more of the tarsal joints may be dislocated. The distal fragment or fragments usually are displaced dorsalward, and sometimes the bones overlap slightly; in these instances, the distal fragment produces a prominence on the dorsum of the foot and the proximal fragment beneath forms a mass on the sole. Occasionally, lateral movements of the foot can be preserved to some extent by osteotomy through the old fracture and reduction of the fragments. Even when resection of the articular surfaces is unnecessary, however, lateral movements usually are lost. Partial or total resection and arthrodesis of one or more of the tarsal joints frequently are required, not only to correct the position of the bones but also to relieve pain and prevent traumatic arthritis. Because lateral movements often are already partially or completely lost, arthrodesis that entirely eliminates lateral motion does not add much to the disability, especially in young people. When the subtalar joint is not involved, its motion should be preserved by fusing only the midtarsal joints.
Unless deformity and pain are severe, operations for malunion in this area are not advisable until weight bearing has been tried for 6 to 12 months.
Make an incision either lateral to the extensor tendons on the dorsum of the foot or middorsally in line with the third metatarsal; reflect the periosteum and expose the old fracture.
If the injury is only a few months old, divide the bones with an osteotome at the fracture; if the fragments overlap excessively, remove a small section from each.
Using a bone skid or periosteal elevator, lever the fragments into position.
The reduction usually is stable; if desired, however, bone staples or crossed Kirschner wires can be used to maintain apposition.
If malunion has been present for several months or years, the tarsus may be completely fused and the old fracture line may be invisible; in these instances, osteotomize the bones without regard to joints or to the possible site of the old fracture. If the deformity is severe, reduction is impossible without wide resection of the bones.
If the malunion has caused tenosynovitis of the extensor tendons and dorsal contracture of the toes, the deformities can be corrected later by an operation for claw toes (see Chapter 87 ).
With the foot at a right angle to the leg, a plaster cast is applied from the toes to just below the knee. After 1 week, radiographs are made through the cast to confirm the position. At 2 weeks, the cast and sutures are removed, the foot is inspected, and, if necessary, any residual deformity is corrected with the patient under general anesthesia. A short leg cast is applied and is worn for 1 month. Impressions for arch supports are made, and a walking boot cast is applied; the cast is well molded beneath the metatarsal necks and the longitudinal arch and is worn for 4 weeks. The cast is removed, and the patient is instructed in foot and toe exercises; the arch supports are worn for 4 to 6 months.
Malunion of a fracture of the talus is always seriously disabling. The neck, body, or both may be involved in the malunion and can produce an irregularity of the ankle joint or the subtalar or talonavicular joint.
Malunited fractures of the neck of the talus are analogous to intracapsular fractures of the neck of the femur in that they often impair circulation and can cause degeneration or even osteonecrosis of the talar head or body and consequent irregularity of one or more of the articular surfaces. Union may occur with the distal fragment in rotation or in lateral or medial deviation, producing a varus or valgus deformity. Treatment of varus malunion of the talar neck has been limited to triple arthrodesis, with unpredictable results. Shortening of the lateral column or lengthening of the medial column to correct forefoot rotation also has been suggested. A talar neck osteotomy at the apex of the deformity with a rhomboid-shaped autogenous tricortical iliac crest bone graft impacted into the osteotomy to maintain correction can be performed; however, care must be taken to preserve the extraosseous blood supply to the talus to prevent osteonecrosis. When the body of the talus is avascular, treatment is as described in Chapter 85 . A triple arthrodesis with resection of suitable wedges of bone may be necessary to correct heel inversion and forefoot varus (see Chapter 85 ).
A malunited fracture of the base of the neck or of the anterior part of the body, with dorsal displacement of the distal fragment, may painfully block the ankle joint anteriorly. Excision of the protruding part of the bone may restore ankle motion, although traumatic arthritis may develop eventually. If symptoms of traumatic arthritis are incapacitating, ankle arthrodesis is indicated.
Fractures of the body of the talus, although rare, often unite in malposition. Disability is extreme when the fracture involves the subtalar or ankle joint or both.
Arthrodesis or talectomy is the preferred treatment. If an articular surface of the talus is grossly distorted, and the bone is viable and is not infected, arthrodesis is the procedure of choice. When the superior and inferior articular surfaces of the talus are irregular, posterior arthrodesis of the ankle (see Chapter 11 ), including the subtalar joint, is preferable. When the body is nonviable, calcaneotibial arthrodesis (see Chapter 89 ) is indicated because motion in the midtarsal joints can be preserved.
Traumatic arthritis may be limited to the ankle joint or to the subtalar joint. In these instances, ankle arthrodesis (see Chapter 11 ) or subtalar fusion may be indicated. Good results have followed subtalar fusion without arthrodesis of the midtarsal joints.
Occasionally, a malunited comminuted fracture of the body or neck of the talus can be treated by pantalar arthrodesis. Pantalar and calcaneotibial arthrodeses are difficult and extensive operations.
For open fractures complicated by infection and draining sinuses and sequestration of the talus, talectomy has been recommended in the past. The technique of excision of the talus is similar to that described for tuberculosis of this bone (see Chapter 23 ). To preserve limb length, we have used Ilizarov circular fixation techniques and bone segment transport after corticotomy of the distal tibia to facilitate calcaneotibial arthrodesis, especially after loss of the talar body from open fractures or sepsis. This technique requires a compliant patient, radical debridement of the infected bone, and appropriate antibiotic therapy.
Pain and disability often persist after fractures of the calcaneus even though the original injury was treated skillfully; this is especially likely if the patient’s occupation requires walking over rough ground. Deformities associated with nonoperative management of calcaneal fractures include heel widening, subtalar incongruity, loss of calcaneal height (decreased Böhler angle), and varus alignment. Heel widening can lead to subfibular impingement and dysfunction of the peroneal tendons. Decreased calcaneal height results in a more horizontally oriented talus, which causes anterior tibiotalar impingement, decreased dorsiflexion, and decreased push-off strength. Impaired calcaneal cuboid motion can occur from overhang of the anterolateral calcaneal wall. Varus deformity leads to excessive stress on the lateral foot, whereas subtalar incongruity causes posttraumatic arthrosis.
Because pain after calcaneal fractures may improve for 1 to 2 years after injury, surgical treatment usually is deferred as long as the patient is making progress in rehabilitation. If a patient’s function fails to progress during this time, however, surgical intervention is warranted. Preoperative evaluation should include analysis of the location of the pain. Lateral pain usually is caused by lateral wall impingement or peroneal tendinitis, whereas more circumferential pain likely is caused by subtalar arthrosis. Anterior ankle pain may be caused by impingement. Posterior ankle pain may be caused by a posterior calcaneal bone spike behind the facet. An injection of 1% lidocaine into the subtalar joint may be helpful in differentiating the origin of the pain. Operative treatment may consist of osteotomy, arthrodesis, or resection of a prominence of the calcaneus laterally to free the peroneal tendons, or a combination of these techniques. A laterally based opening wedge osteotomy for extraarticular malunited fractures has been reported with good results for patients with a symptomatic heel valgus before the onset of subtalar arthritis. If arthrodesis is considered, having the patient wear a limited motion, double upright brace or prefabricated walking boot for 8 weeks can be useful in predicting the success of the procedure.
Although smoking is not an absolute contraindication to surgical management, smoking increases the incidence of nonunion after subtalar arthrodesis and the likelihood of wound complications. Smokers should be encouraged to quit preoperatively and be counseled about potential complications.
Radiographic evaluation includes standard lateral and lateral weight-bearing radiographs and views of the calcaneus. A Broden view can provide information about the subtalar joint; however, a CT scan most accurately shows alignment and subtalar congruity. CT scans are obtained in the transverse and coronal planes.
Stephens and Sanders used CT to identify three types of calcaneal malunions ( Fig. 58.2 ) and to develop treatment guidelines ( Table 58.1 ). Using these guidelines in 26 malunions, they obtained 18 excellent, five good, and three fair results. Although outcomes deteriorated as the complexity of the malunions increased, significant clinical improvement was obtained in even the most severe deformities. In a follow-up study, Clare et al. reported that the extensile lateral approach allowed adequate decompression of the peroneal tendons, bone block arthrodesis, and calcaneal osteotomy all through the same incision, which is not possible with other proposed approaches (Gallie, Ollier). Ninety-three percent of the arthrodeses united, all feet were plantigrade, and 93% were in neutral or valgus alignment. Twenty-four percent had delayed healing, but only one deep infection occurred, and no free-tissue transfers were necessary. A nonsignificant trend toward increased nonunion and wound problems was noted in smokers, and mild residual pain was present in 64% of patients, usually lateral in location. There were no implant failures, which the authors attributed to using large (7.3 or 8.0 mm) titanium screws placed with a lag technique.
Type I | Lateral exostectomy through extensile L-shaped lateral incision |
Type II | Lateral exostectomy plus subtalar arthrodesis using resected exostosis as graft |
Type III | Lateral exostectomy plus subtalar arthrodesis plus calcaneal osteotomy |
Flemister et al. found that outcomes were similar regardless of the reconstructive procedure—lateral calcaneal closing wedge osteotomy, bone block arthrodesis, in situ fusion—but malunion and nonunion were more frequent after bone block procedures (15%) than after in situ fusions (5%). They recommended in situ fusion, unless anterior ankle impingement requires a more complicated bone block fusion.
If the subtalar joint alone is involved, enough bone is resected to correct the weight-bearing alignment and the joint is arthrodesed. If the midtarsal joints also are involved, a triple arthrodesis (subtalar, talonavicular, and calcaneocuboid) is advisable. Romash described a reconstructive osteotomy of the calcaneus with subtalar arthrodesis for malunited calcaneal fractures with satisfactory results. According to him, the reconstructive osteotomy, which re-creates the primary fracture, allows repositioning of the tuberosity to narrow the heel, alleviates impingement, and returns height to the heel; the subtalar arthrodesis alleviates the symptoms of posttraumatic arthritis. Good or excellent results also have been reported with subtalar distraction realignment arthrodesis using lateral decompression, medial subtalar capsulotomy, and distraction and realignment of the subtalar joint with a tapered wedge bone graft ( Fig. 58.3 ). The lateral approach has several advantages over the Gallie-type posterolateral approach, including less soft-tissue dissection, good view of the subtalar joint, easier access to the medial subtalar capsule and sustentaculum tali, and decreased risk of damage to the sural nerve.
Several bone block fusion techniques to restore heel height and improve talar inclination have been described with union rates of 80% to 100% with no varus malunions. However, one study reported good results in only seven of 14 patients, and another study reported varus malunions of the arthrodesis in four of 15 patients. Trnka et al. reported 29 complications after subtalar bone block arthrodesis. Four of the five nonunions in their series were in patients in whom allografts were used, and they cautioned against allograft use. Bone block fusion rather than in situ fusion has been recommended for patients with loss of heel height; however, satisfactory results have been reported even with loss of heel height using subtalar arthrodesis without interpositional bone grafting. Distraction arthrodesis should be considered only for patients with less than 10 degrees of ankle dorsiflexion and disabling pain. For a severe crushing fracture of the calcaneus, either fresh or malunited, triple arthrodesis has been recommended because there is not only derangement of the subtalar joint but also a subluxation of the calcaneocuboid and talonavicular joints caused by depression of the sustentaculum tali. With subtalar fusion alone, the head and neck of the talus are left projecting forward without support and form a constant lever in weight bearing that interferes with fusion. According to Conn, triple arthrodesis is preferable to subtalar fusion because the talonavicular, calcaneocuboid, and subtalar joints have a reciprocal action and because triple arthrodesis does not add to the disability since little midtarsal motion remains after the original injury. Others, however, believe that triple arthrodesis has no advantage in most patients with calcaneal malunions. We believe that unless the midtarsal joints are involved, arthrodesis should be limited to the subtalar joint; motion in the midtarsal joints may increase with activity and should be preserved.
Gallie advised arthrodesis of the subtalar joint from the posterior aspect because the procedure is simpler than the one usually employed ( Fig. 58.4 ); however, it does not allow correction of varus or valgus position of the calcaneus or of any other deformity of the foot. According to Gallie, a mild valgus position of the heel usually can be disregarded. His operation is not suitable if the primary deformity is one of varus because excessive weight would be borne on the head of the fifth metatarsal and cause a painful callus.
(GALLIE)
With the patient prone, make a longitudinal incision along the lateral border of the Achilles tendon for 6 to 8 cm and incise transversely the posterior capsule of the ankle and of the subtalar joint.
Locate the subtalar joint by medial and lateral motions of the calcaneus.
Probe the subtalar joint to determine its general direction and cut a mortise in the calcaneus and talus approximately 1.3 cm wide, 0.6 cm deep, and as far distally as the sinus tarsi.
Flex the knee and remove a graft 6.2 cm long × 1.3 cm wide from the anteromedial surface of the proximal tibia. Divide the graft into two parts and bevel one end of each.
Pack cancellous bone into the depth of the mortise. With their cortical surfaces apposed, drive the two grafts into the mortise. If the grafts are of the proper size, their cancellous surfaces press snugly against the lateral walls of the mortise. Strips of cancellous bone from the ilium probably are preferable to the tibial grafts used by Gallie; they are packed tightly into the cavity.
Close only the subcutaneous and skin layers over a suction drain.
Apply a bulky dressing followed by a short leg cast.
(CARR ET AL.)
Place the patient in the lateral decubitus position with the affected side up. Prepare and drape the posterior iliac crest.
Under tourniquet control, make a longitudinal posterolateral Gallie-type approach to the subtalar joint. There should be no horizontal extension of this incision to avoid undue tension on the wound.
Expose the lateral calcaneal wall subperiosteally and excise it to a more normal width (lateral wall decompression). This step should ensure peroneal and fibular decompression.
Identify the subtalar joint and apply a femoral distractor with half-pins in the medial subcutaneous tibia and medial calcaneus. The medial application helps to correct hindfoot varus.
Apply distraction and denude the posterior subtalar joint to subchondral bone. Use a lamina spreader to aid in subtalar joint exposure.
Correct any heel varus or valgus by manipulation.
Obtain intraoperative radiographs to ensure correction of the lateral talocalcaneal angle (normally 25 to 45 degrees). A weight-bearing view of the opposite foot obtained preoperatively is helpful in confirming a normal talocalcaneal angle.
Measure the subtalar joint gap and harvest an appropriately sized tricortical posterior iliac crest bone graft. A block 2.5 cm in height may be required for severe deformity. Two separate pieces may be required to fill the gap completely and help prevent late collapse into varus or valgus.
After inserting the graft, release the distraction forces.
Insert two fully threaded, 6.5-mm AO cancellous screws through stab incisions in the heel to fix the calcaneus and the talus firmly. Two screws provide rigid fixation and help prevent rotatory movements around the axis of subtalar motion. Fully threaded screws are used to help prevent late collapse ( Fig. 58.5 ).
Obtain final radiographs to confirm position before wound closure.
The drain is removed at 24 hours. The foot is elevated for 72 hours, and the cast is not bivalved if the neurovascular status remains satisfactory. Crutch walking without weight bearing is allowed. At 2 weeks, the cast and sutures are removed and a well-molded short leg nonwalking cast is applied and worn 4 weeks. Active toe exercises are encouraged during this time. During the first 6 weeks, if patient compliance concerning weight bearing is questionable, a long leg cast with the knee bent is applied. At 6 weeks, a short leg walking cast is applied and weight bearing to tolerance is allowed. Radiographs of the arthrodesis are obtained at 6 and 12 weeks. Usually a leather lace-up shoe with a rigid shank can be worn after 12 weeks, in conjunction with a leather lace-up ankle corset to control edema for another 4 to 6 weeks. The patient should be informed preoperatively that swelling around the hindfoot may persist for 6 to 9 months after surgery.
According to Kashiwagi, pain in malunited fractures of the calcaneus sometimes is caused by changes around the peroneal tendons. The tendons may be buried in callus, caught by bony fragments, affected by adhesions, or displaced superiorly by a bony prominence. Kashiwagi recommended peroneal tomography to show changes around the tendons and their sheaths ( Fig. 58.6 ). If pain is caused by such changes, he advised freeing the tendons and sheaths, resecting the bony prominence laterally, and, if necessary, subtalar arthrodesis.
(KASHIWAGI, MODIFIED)
Make a Kocher incision, but extend its distal half one fingerbreadth superior to the sole of the foot and end it at the base of the fifth metatarsal.
Identify the peroneus longus and brevis tendons, and, without opening their sheaths, deepen the incisions to the lateral surface of the calcaneus 0.6 cm inferior to the peroneus longus tendon. Extend the dissection superiorly next to the bone and deep to the tendons, separating the peroneal retinaculum from the bone.
Retract the tendons superiorly over the tip of the lateral malleolus. Free the origin of the extensor digiti brevis from the calcaneus and retract it superiorly also. The lateral surface of the calcaneus is exposed, including the lateral aspect of the subtalar and calcaneocuboid joints.
With a wide osteotome, make a sagittal osteotomy through the calcaneus extending from the calcaneocuboid joint anteriorly to the tuberosity of the bone posteriorly and from the subtalar joint superiorly to the plantar surface inferiorly.
Discard the bone resected. The lateral side of the calcaneus should now consist of a vertical wall, all excessive bone lateral to the subtalar joint and inferior to the lateral malleolus having been removed.
The lateral aspects of the subtalar and calcaneocuboid joints are now exposed; if necessary, arthrodese these joints.
Replace the peroneal tendons and sheaths inferior to the lateral malleolus and suture the peroneal retinaculum to the plantar fascia.
Close the wound.
With the knee flexed 30 degrees, apply a long leg cast.
At 10 to 14 days, the cast and sutures are removed. If the operation includes an arthrodesis, a short leg walking cast is applied and the postoperative care is the same as for triple arthrodesis (see Chapter 85 ).
(CLARE ET AL.)
Place the patient in the lateral decubitus position on a beanbag, with the normal leg down and in front of the injured extremity.
Place a thigh tourniquet. Prepare and drape the leg and exsanguinate the extremity with the use of an Esmarch bandage. Inflate the tourniquet to 350 mm Hg.
Make a lateral extensile incision over the calcaneus and raise a full-thickness subperiosteal flap. The vertical limb of the incision should be just anterior to the Achilles tendon and posterior to the sural nerve, allowing the nerve to be elevated with the full-thickness flap posteriorly. Avoid violation of the nerve at the terminal portion of the horizontal limb of the incision.
Place three 1.6-mm Kirschner wires, one in the distal fibula, one in the talar neck, and the third in the cuboid, for retraction of the peroneal tendons and the subperiosteal flap.
Carefully free the lateral wall of the calcaneus of all adjacent soft tissue as far distally as the calcaneocuboid articulation. In all three types of calcaneal malunions, the lateral wall exostosis must be resected.
Place a Hohmann retractor on the plantar aspect of the calcaneus and one on the anterior process of the calcaneus, and perform an exostectomy using a thin-bladed AO osteotomy saw (Synthes USA, Paoli, PA). Starting posterior, angle the saw blade slightly medially relative to the longitudinal axis of the calcaneus, leaving more residual bone plantarly and providing decompression of the area of impingement in the subfibular region ( Fig. 58.7A ). Do not violate the talofibular joint.
Continue the exostectomy to the level of the calcaneocuboid joint because the residual overhang of the lateral wall often results in an osseous block to motion of this joint. Remove the overhang and the lateral fourth of the distal aspect of the calcaneus because articulation of this lateral portion with the cuboid is almost always arthritic.
Complete the exostectomy distally with an osteotome to avoid saw blade damage to the cuboid and remove the fragment en bloc ( Fig. 58.7B ). The excised lateral wall fragment should be maintained as a single fragment, if possible, for later use as a bone block autograft in type II and type III malunions.
In type II and type III calcaneal malunions, attention is directed to the subtalar joint. If it is arthritic, perform a subtalar arthrodesis. Place a lamina spreader within the joint and debride the remaining articular surface using a sharp periosteal elevator or osteotome.
Prepare the inferior talar and superior calcaneal osseous surfaces with a 2.5-mm drill bit, creating multiple perforations within the subchondral bone for vascular ingrowth.
With the lamina spreader fully expanded within the subtalar joint posteriorly, verify by fluoroscopy how much height needs to be obtained. The talar head should align anatomically with the navicular, indicating restoration of the medial column, the normal angle of talar declination, and the talocalcaneal angle.
When alignment is confirmed radiographically, measure the dimensions of the defect with a ruler, allowing the autograft bone block to be contoured to match the defect. If the joint is excessively tight medially, place lamina spreaders in the sinus tarsi and the posterior facet of the subtalar joint. A femoral distractor placed medially is not used because it is cumbersome and not as effec tive as direct intraarticular distraction. Avoid incising the deltoid ligament from inside the subtalar joint because this renders the joint unstable and overdistraction of the graft may result.
Place the previously excised lateral wall fragment within the joint as an autograft bone block ( Fig. 58.7C ). This bone can be folded over on itself to obtain more height if needed, but it should fill the subtalar joint because the height of the lateral calcaneus (and the graft) usually is equal to the width of the posterior facet. Additional cancellous allograft chips may be placed in the debrided sinus tarsi to assist fusion.
If a subtalar arthrodesis alone is needed (type II malunion), place fixation at this point. With the subtalar joint held in neutral to slight valgus alignment, place two terminally threaded 3.2-mm guide pins percutaneously from the posterior plantar edge of the calcaneus, and advance across the subtalar joint perpendicular to the plane of the posterior facet and into the talar dome. Angle the guide pin in a divergent fashion into the talar dome for increased stability. Avoid placing a pin in the lateral aspect of the ankle joint.
Obtain fluoroscopic anteroposterior and mortise images of the ankle and obtain an axial radiograph of the calcaneus to verify correct pin placement and hindfoot alignment.
If more stable fixation is required, place a third guide pin from the plantar margin of the anterior process of the calcaneus into the distal aspect of the talar neck and head for more stable fixation. Avoid violating the talonavicular joint.
Place large fragment, partially threaded (7.3 or 8 mm) cannulated screws in lag mode for definitive fixation.
In patients with a type III malunion, correction of axial malalignment also is necessary. Because rotation of the midfoot in the coronal plane around an anteroposterior axis (pronation-supination) would not correct a malpositioned calcaneal tuberosity healed in varus or valgus, a calcaneal osteotomy is performed before placement of the fixation for subtalar arthrodesis. For varus malalignment, perform a Dwyer lateral closing wedge osteotomy posterior to the posterior facet ( Fig. 58.7D ). Use a medial displacement calcaneal osteotomy with rotation for valgus malalignment.
When the osteotomy is completed, insert the guide pins in the manner described earlier. In this way, the osteotomy and the fusion can be compressed simultaneously. If bone is removed during the closing wedge osteotomy, it can be used as graft material as well.
Remove the Kirschner wires and examine the tendons for dislocation. In many ankles with obvious preoperative tendon subluxation, removal of the exostosis allows the tendons to fall back behind the fibula and no further treatment is needed. The peroneal tendon sheath should be entered distally with a Freer elevator, however, to evaluate sheath stenosis proximally.
If stenosis is found, incise the sheath over a length of 2 to 3 cm along the undersurface of the subperiosteal flap so that a tenolysis can be performed.
If a peroneal tendon dislocation is identified, reconstruct the superior peroneal retinaculum through a small separate incision in the flap.
Place a deep drain exiting at the proximal tip of the vertical limb of the incision and close the subperiosteal flap in a layered fashion.
Pass interrupted 0 Vicryl sutures in the deep layers of the subperiosteal flap, angling such that the flap is advanced to the apex of the incision.
Clamp the sutures until all deep sutures have been placed. When completed, hand-tie the sutures sequentially, starting at the proximal and distal ends and working toward the apex of the incision.
Close the subcuticular layer in a similar fashion with interrupted 2-0 Vicryl. Close the skin with 3-0 nylon suture, starting at the ends and progressing toward the apex. If height restoration prevents wound closure, the vertical limb of the incision can be extended proximally to allow the flap to shift and rotate downward, with the proximal wound being left open to granulate.
Patients with type I malunions are kept non–weight bearing until the incision has healed, and physical therapy with early range-of-motion activities and gait training with full weight bearing is initiated thereafter, usually by 3 weeks. Patients with type II and type III malunions are kept non–weight bearing with the leg in a cast for 12 weeks (with cast changes every 4 to 6 weeks). This is followed by progression of weight bearing and the initiation of physical therapy after radiographic evidence of union of the subtalar fusion mass is confirmed.
For malunited extraarticular fractures, Aly described a laterally based opening wedge osteotomy for symptomatic valgus calcaneal deformity in 34 patients. He obtained good or excellent results in 91% and poor results in 9% at a mean follow-up of 56.2 months. The mean AOFAS hindfoot and ankle score improved from 57 preoperatively to 90 postoperatively. In the patients with poor results, bilateral fractures and subtalar arthritis contributed to their gait abnormality and restricted hindfoot motion.
(ALY)
Approach the calcaneus through an oblique lateral incision. Protect and retract the superficial branches of the peroneal nerve.
Identify the sustentaculum tali by probing over the dorsum of the exposed calcaneus.
Shave the lateral border of the widened calcaneus. Incise the periosteum in line with the planned osteotomy, starting laterally approximately 2.5 cm proximal to the calcaneocuboid joint in the interval between the middle and posterior facets of the subtalar joint.
Make a lateral to medial oblique osteotomy. The osteotomy line should be made slightly oblique from proximal-lateral to distal-medial. The required depth of the osteotomy should be estimated from the preoperative calcaneal axial radiographs.
Open the osteotomy with a large osteotome. Preserve the periosteum of the medial calcaneus to prevent medial displacement of the posterior fragment.
Take a suitable tricortical bone graft from the posterior iliac crest and place it into the osteotomy site and add the bone shavings.
Through a posterior approach, place one cannulated screw through the long axis of the calcaneus.
Postoperatively, the patient is kept non–weight bearing in a cast for 6 weeks and then placed in a walking cast for an additional 6 weeks. Thereafter, the patient may wear normal shoes.
Occasionally, malunion occurs after the most accurate reduction of closed ankle fractures or more commonly after “stable” injuries that displace with widening of the mortise because of syndesmotic disruption. Malunion also can develop if fixation of the fibula is inadequate and the fibula is allowed to shorten and rotate. Disability from a malunited ankle fracture can be so extreme that relief can be obtained only by surgery. Even a minor varus or valgus deformity of the joint produces an abnormal weight-bearing alignment and posttraumatic arthritis. Although one cadaver study suggested that factors other than the magnitude of normal contact stresses are of greater importance in the pathogenesis of posttraumatic arthritis, another cadaver study found that 2 mm or more of shortening or lateral displacement and 5 degrees or more of external rotation increase contact pressures significantly in the posterolateral and midlateral quadrants of the talar dome, and a corresponding decrease in the contact pressures was noted in the medial quadrants of the talar dome. Anatomic reduction of pronation-lateral rotation fractures of the lateral malleolus was recommended to diminish the risk of posttraumatic arthritis.
Osteotomies to correct uncomplicated deformities caused by recently malunited fractures of the ankle usually are satisfactory, but displacement of the talus within the ankle mortise for more than 3 months may result in pathologic changes in the articular cartilage, with a diminished potential for satisfactory outcome with osteotomy. Some authors, however, have reported improvement in patients with adequate surgery after displacement of more than 3 months. Nevertheless, all agree that when the deformity has been of short duration and has been corrected with minimal trauma to the articular surfaces, good function usually can be obtained if the normal weight-bearing alignment of the lower extremity and the normal relationships between the articular surfaces of the tibia, the fibula, and the talus are restored ( Fig. 58.8 ). Displacement and residual tilt of the talus have been associated with poor results, as have inaccurate reduction and poor surgical technique.
Osteotomies have been less successful in treating bimalleolar malunions associated with moderate-to-severe arthritis. An osteotomy can restore weight-bearing alignment of the ankle, but pain and swelling can persist because of arthritic deterioration. Some authors recommend realignment osteotomies as the initial treatment of all symptomatic ankle malunions, regardless of the age of the patient, time from initial injury, severity of malunion, or presence of arthritic changes. However, although arthritis is not a contraindication to osteotomy, chondral damage has been found to be indicative of a poor result. Ankle arthrodesis or ankle arthroplasty should be considered in patients with severe arthritic changes and severely impaired function or in patients who remain significantly symptomatic after osteotomy. It is important to remember that walking on rough ground is difficult after arthrodesis, especially if the subtalar joint is secondarily fibrosed or ankylosed. Complications as high as 30% have been reported after ankle arthrodesis, including nonunion and malunion.
Paley et al. treated malunion after ankle arthrodesis with Ilizarov reconstruction. They concluded that the Ilizarov apparatus can simultaneously treat the foot deformity, length discrepancy, and infection, achieving a solid union and plantigrade foot. However, 20 major complications that required surgery occurred during treatment and seven occurred after frame removal, four of which required additional surgery.
There are three requirements for the anatomic restoration of the ankle joint: (1) a perfectly equidistant and parallel joint space; (2) a fibular spike in its normal position pointing exactly to the level of the distal tibial subchondral bone, indicating that the length of the fibula is correct; and (3) a normal contour at the lateral part of the articular surface of the talus in continuity as an unbroken curve to the recess of the distal fibula where the peroneal tendons lie.
Up to 78% good results have been reported with fibular osteotomy and lengthening for ankle malunion. The criteria for osteotomy include radiographic confirmation of malunion ( Fig. 58.9 ), a demonstrable joint space on anteroposterior and mortise views, and remaining articular cartilage covering the tibial plafond and the talus. Contraindications include ankylosis, loss of bone stock, and severe degenerative arthritis.
Operations to correct malunited ankle fractures are (1) osteotomy of the fractured fibula or medial malleolus or both with restoration of fibular length and internal fixation of the osteotomies, (2) supramalleolar osteotomy when only realignment of the lower extremity is required, and (3) arthrodesis of the ankle with or without supramalleolar osteotomy. Although a variety of malunions can occur, the procedures described here can be modified to treat most malunions.
Make a longitudinal lateral incision over the old fibular fracture, curving slightly anteriorly at its distal end.
With an osteotome or oscillating saw, make either a transverse or an oblique osteotomy of the fibula at the area of the old fracture.
Excise scar tissue between the fibula and tibia to allow correct positioning of the fibula in the notch. Length and rotation of the fibula can be restored with the technique described by Weber.
Attach a five-hole or six-hole, 3.5-mm dynamic compression plate to the distal fibular fragment with two screws ( Fig. 58.10A ). Before plate application, make a small recess in the distal fibula so that the plate is not prominent. Place the plate slightly posterior on the distal fragment to allow internal rotation of the fragment. Correct the rotation of the distal fragment by internally rotating it 10 degrees.
Attach the articulated tensioning device from an AO small fragment system to the proximal end of the plate ( Fig. 58.10B ). Apply distraction until the distal fibula is reduced anatomically to its articulations with the tibia and talus.
Confirm the reduction with radiographs or fluoroscopy.
If a transverse osteotomy has been made, fill the gap created by distraction with a small wafer of corticocancellous bone from the medial tibial metaphysis above the medial malleolus ( Fig. 58.10C ).
Change the AO tensioning device to the compression mode and apply compression to the osteotomy site. Attach the plate to the proximal fibula using three 3.5-mm cortical screws. Yablon and Leach recommended the addition of a syndesmosis screw if the interosseous membrane is detached during the fibular dissection. In very distal fractures, it may be necessary to stabilize the fibula with transfixing Kirschner wires.
Alternatively, Ward et al. described the use of the small AO distractor to restore fibular length and rotation. Expose the fibula, resect scar tissue, and osteotomize the fibula as previously described.
Insert two 2.5-mm partially threaded pins in the anterior distal fibular fragment in 10 degrees of external rotation.
Correct rotation of the distal fragment and insert two 2.5-mm pins into the proximal fibula in the same plane.
Attach the small AO distractor and distract the fibula until it is anatomically aligned.
Fill the gap with bone graft and apply compression with the distractor.
Apply a one third tubular plate to stabilize the fibula.
Operations for diastasis of the tibia and fibula should allow a shift of the talus medially and repositioning of the lateral malleolus. Yablon and Leach reported that a more extensive dissection usually is necessary to restore anatomic alignment in fibular malunion associated with lateral shift of the talus.
Make a fibular osteotomy and rotate it distally 180 degrees to allow removal of an adequate amount of scar from the area of syndesmosis.
Make a second incision over the anterior aspect of the medial malleolus and excise scar tissue between the medial malleolus and talus.
Reduce the talus and place a Steinmann pin from the tibia into the talus to hold the reduction temporarily while the fibula is reduced and plated, as described for bimalleolar malunions.
If the medial malleolus also has united in a poor position, make a second longitudinal incision just proximal to its base and drive an osteotome from above through four fifths of the diameter of the medial malleolus distally and laterally. Make this osteotomy through the medial part of the tibia just above the old fracture to obtain a broader bony surface. Refracture the bone by forcefully adducting the foot.
Stabilize the medial malleolus with parallel small fragment lag screws and Kirschner wires as necessary.
If a gap has been created by reduction of the medial malleolus, insert bone graft to prevent future collapse. Use a small fragment one third tubular plate as a buttress if necessary.
Obtain intraoperative radiographs to confirm anatomic reduction of the ankle.
A cast is applied over padding from the tibial tuberosity to the toes with the foot in neutral position. The cast is changed in 2 weeks, the sutures are removed, and a cast is reapplied and worn for 10 to 12 weeks. If stable fixation is obtained in a compliant patient, a removable cast brace that does not allow rotation can be substituted to allow controlled physical therapy. An ankle brace with a medial T-strap and an arch support may be necessary for an additional 10 to 12 weeks and can be worn for 3 to 6 months after difficult reconstructions. Physical therapy should be used to restore the soft tissues and encourage strengthening of the bone.
Occasionally, a malunion of the distal tibia and fibula occurs in which the normal tibiotalar relationships are retained but the ankle is in valgus or varus. A supramalleolar osteotomy is recommended for this malunion. Opening wedge, closing wedge, or dome osteotomies can be used. Because dome osteotomies do not sacrifice length to gain correction of the deformity, they may be preferred in malunions associated with shortening. Dome osteotomies are more effective, however, in correcting deformity in the frontal (varus-valgus) plane than in the sagittal (flexion-extension) plane. A properly positioned wedge osteotomy can be used to correct multiplanar deformities. Closing wedge osteotomies provide broad bony surfaces for healing but cause some shortening of the extremity. Opening wedge osteotomies maintain length, but bone grafting is required to fill the gap created. The Ilizarov method of gradual deformity correction with distraction osteogenesis also can be used.
To create a dome osteotomy, expose the distal tibia through an anterolateral Henry approach (see Chapter 1 ).
Use a 3.2-mm drill bit to create a series of holes in the distal tibial metaphysis in the shape of an arc, convex superiorly. The medial and lateral edges of the arc should be 1.0 to 1.5 cm proximal to the ankle joint, and the height of the arc should be 1.0 to 1.5 cm ( Fig. 58.11A ).
Through the same incision or a separate lateral incision, expose the fibula and make an osteotomy at the same level as the tibial osteotomy. If the fracture has healed in varus, resect 1 to 3 cm of the fibula to correct the deformity. If the fracture has healed in valgus, make an oblique osteotomy of the fibula. Use an oscillating saw to connect the holes drilled anteriorly, medially, and laterally in the tibia.
With fluoroscopic control, insert a 4- or 5-mm threaded pin transversely from medial to lateral into the distal tibial fragment parallel to the joint line. Keep the pin out of the joint, the osteotomy site, and the neurovascular bundle.
Insert a second 4-mm or 5-mm bicortical threaded pin 6 to 10 cm proximal to the osteotomy and parallel to the knee joint.
With an osteotome, complete the tibial osteotomy through the posterior cortex. Correct varus or valgus deformity by making the pins parallel ( Fig. 58.11B ).
If complete reduction is not obtained, it may be necessary to resect more of the fibula or to release more soft tissue, including the interosseous membrane.
When the reduction is acceptable, connect the pins with an external fixator bar and apply compression. Additional external fixation pins can be placed in the tibia and talus.
Alternatively, if the soft-tissue coverage is adequate, stabilize the osteotomy with a 3.5-mm dynamic compression plate and remove the two external fixation pins. The fibula also can be stabilized with a one third tubular plate if desired. Bone grafting is left to the surgeon’s discretion.
An opening or closing wedge osteotomy can be made in the following manner. Through a lateral longitudinal incision, expose and osteotomize the fibula as previously described to correct either varus or valgus deformity.
Through the same incision, expose the lateral surface of the tibia 1.3 cm proximal to the joint line and drive a wide osteotome transversely almost through the bone; carry out a manual osteoclasis. Insert cancellous iliac bone, or use a wedge-shaped graft taken from the shaft of the tibia into the lateral side of the osteotomy to pack it open.
Stabilize the osteotomy with an external fixator applied in the standard fashion with pins through the tibia and talus.
If the fractures have healed in varus position, a closing wedge osteotomy of the tibia can be made in a similar fashion or internal fixation with a plate and screws can be used in conjunction with autogenous iliac bone grafts.
Close the wound in layers and apply a bulky dressing if an external fixator has been used.
If not, apply a cast from the tibial tuberosity to the toes.
If casting was used, the cast and the sutures are removed at 2 weeks and then a new cast is reapplied. Weight bearing is not permitted for 6 weeks. If external fixation was used, it is removed at 6 to 8 weeks, and a short leg walking cast is applied. Weight bearing is progressed as tolerated, and the cast is removed when the osteotomies have healed (12 to 16 weeks after surgery). Rehabilitation of the lower extremity is begun by physical therapy.
Arthrodesis is indicated as a primary procedure in the following types of malunited fractures of the ankle:
Malunited bimalleolar fractures, with or without significant deformity, in which radiographs show definite traumatic arthritic changes to be the cause of persistent pain and disability ( Fig. 58.12 )
Malunited trimalleolar fractures of long duration with posterior and proximal dislocation of the talus
Malunited fractures in which the deformity cannot be completely corrected by conservative reconstruction or in which such extensive surgery is required for correction that arthritic changes in the ankle are inevitable
When malalignment is marked, it should always be corrected by osteotomy at the time of arthrodesis; otherwise, a foot strain can be severely disabling later. This additional procedure does not materially complicate the operation or delay recovery. See Chapter 11 for techniques of arthrodesis of the ankle.
In malunions of the shafts of the tibia and fibula, the degree of deformity that requires surgery is not clearly defined. It is widely believed that angular deformities of the tibial shaft cause alterations in the contact pressures of the knee and ankle joints and predispose them to the development of osteoarthritis. Clinical series with long-term follow-up have not always supported this hypothesis, however. One study found that the ankle joint is more affected than the knee and that the location of the fracture is significant. Poorer functional ankle scores were correlated with the degree of malalignment and the proximity of the deformity to the ankle joint. Varus deformities were more poorly tolerated than were valgus deformities. A later study found just the opposite, that symptoms at the knee were correlated with arthritic changes, whereas symptoms at the ankle were not. In addition, no relationship was shown between the location of the fracture and development of osteoarthritis of the knee or ankle. Rotational deformity also was not associated with arthritic changes.
Milner et al. determined that fracture malunion did not cause a higher incidence of ankle and subtalar arthritis ipsilateral to the fracture. There was a trend toward a higher prevalence of medial compartment osteoarthritis of the knee in patients with varus malalignment of the limb, and shortening of 10 mm or more correlated with subjective complaints of knee pain. Although osteoarthritis occurred more frequently on the side of the fracture, factors other than malalignment were believed to contribute more to the development of osteoarthritis.
The degree of acceptable deformity noted by various authors is extremely variable. Surgery has been recommended for valgus deformity of more than 12 degrees, varus deformity of more than 6 degrees, external rotation deformity of more than 15 degrees, or internal rotation deformity of more than 10 degrees. Shortening of 2 cm or less usually is well tolerated with shoe modifications, but more than 2.5 cm of shortening can cause significant disability.
When surgery is considered for correction of a tibial malunion, the degree of the deformity, the patient’s symptoms, the condition of the injured extremity, and the functional demands of the patient all must be taken into account. Disability from malunion of the tibial shaft is produced mainly by rotational deformity, lateral and posterior bowing, and usually some degree of shortening. Often a resulting contracture of the Achilles tendon causes an equinus deformity of the foot. Symptoms may include ankle, knee, or back pain; gait disturbances; and a cosmetically unacceptable deformity. The limb must be evaluated for a history of neurologic or vascular injury, adequacy of soft-tissue coverage, and presence of infection. With a history of vascular injury, preoperative arteriograms can be helpful in determining the operative approach. If soft tissues in the area of the planned operative site are poor, a simultaneous rotation or vascularized free tissue transfer flap may be necessary to promote bone healing and prevent wound complications. In a patient with a previous infection, preoperative indium-labeled white blood cell scans, gallium scans, or technetium scans can help to determine the activity of the infection. It is generally desirable to treat the infection before osteotomy for malunion. Equinus contractures should be corrected by lengthening the Achilles tendon.
When planning an osteotomy, the amount of angular and rotational deformity, leg-length discrepancy, and translation must be determined. Simple opening wedge, closing wedge, or dome-shaped osteotomies can be used to correct relatively small degrees of malunion; however, closing wedge osteotomies can create additional shortening and opening wedge osteotomies often require bone grafting. Oblique osteotomies can be used to correct multiplanar deformities. These osteotomies provide broad surface areas for healing, and lengthening can be obtained by sliding the osteotomy distally. Angular deformities in the frontal (varus-valgus) and sagittal (flexion-extension) planes can be resolved into a uniplanar deformity in an oblique plane ( Fig. 58.13 ). The degree of maximal deformity is greater than the angular measurements on either anteroposterior or lateral radiographs. The plane of maximal deformity can be found by rotating the leg under fluoroscopy until the maximal degree of deformity is seen. A radiograph taken at 90 degrees to this plane should show no deformity. The oblique osteotomy should be made perpendicular to the plane of maximal deformity. Rotational deformity can be evaluated with CT or clinically by measuring the intermalleolar angle. Preoperative planning should include drawings of the injured and uninjured extremities, the site and configuration of the planned osteotomy, and the type of internal fixation device to be used. To prevent neurologic complications, somatosensory evoked potentials should be used during correction of a severe deformity, especially if lengthening is involved. Although the osteotomy usually is performed at the site of the old fracture, a supramalleolar osteotomy (see Technique 58.10) may be preferable if the previous fracture has been slow to heal, is covered with poor soft tissue, or contains extremely dense sclerotic bone. Russell et al. described a clamshell osteotomy for treatment of complex nonunions of the tibial or femoral diaphysis and noted that it is especially helpful in malunions that have a long malaligned segment.
Satisfactory alignment after osteotomy is difficult to maintain without some type of internal fixation, such as a compression plate or intramedullary nail or external fixation. If an intramedullary nail is used, the medullary canal must be opened at both ends of the old fracture, and any gaps created by the osteotomy should be filled with cancellous bone. Reamed, locked intramedullary nailing has been recommended for stabilization of osteotomies made to correct tibial malunions. We prefer to use statically locked nails to increase the stability of the osteotomy. The limited incisions used for the osteotomy are closed after opening of the medullary canals in both fragments and passing of the reaming guidewire but before reaming and nail insertion. Static locking can be converted to dynamic locking in several weeks if needed to promote healing. If a large amount of soft-tissue stripping is necessary to correct the deformity, fixation methods other than intramedullary nailing are preferable because intramedullary reaming often devascularizes the exposed bone segment further. A history of previous external fixation, especially if associated with pin track infection, also is a relative contraindication to intramedullary nailing because of an increased risk of infection.
Oblique tibial osteotomies stabilized with dynamic compression plates and lag screws have been advocated for the treatment of multiplanar tibial deformities with good results ( Fig. 58.14 ). Sanders et al. recommended this technique for tibial shaft deformities that require less than 2.5 cm of lengthening. Contraindications to this procedure include inadequate soft-tissue coverage and active infection. The inability to restore full length, delayed union, plate failure, infection, vascular injury, and wound dehiscence are possible complications.
Osteotomies for infected tibial malunions and malunions associated with a poor soft-tissue envelope may be best treated by the Ilizarov technique of corticotomy and gradual correction of deformity with a ring and wire fixator to correct tibial malunions. This technique is described in Chapter 54 .
(SANDERS ET AL.)
Place a tourniquet on the proximal part of the thigh. Prepare and drape both legs so that they can be compared after correction.
If axial lengthening is planned, place electrodes for measurement of somatosensory evoked potentials.
Under fluoroscopic control, insert a 6-mm Schanz pin in the proximal tibial metaphysis absolutely parallel to the proximal tibial articular surface ( Fig. 58.15A ). Similarly, place a 6-mm Schanz pin in the distal tibial metaphysis absolutely parallel to the tibial plafond.
If lengthening is planned, or if the fibula interferes with correction of the tibia, make an oblique fibular osteotomy, ideally at the level of the proposed site of the tibial osteotomy.
Exsanguinate the leg with a pressure bandage, inflate the tourniquet to 300 mm Hg (39.99 kPa), and remove the pressure bandage.
Make a standard anterior extensile incision to expose the tibia.
Identify the area of malunion and subperiosteally dissect all soft tissue from the area. Place Hohmann retractors to protect the neurovascular structures.
Sculpt the bone to remove excess callus while the tibia is still intact; save the bone that is removed to be used later as a local graft.
Place a femoral distractor (Synthes USA, Paoli, PA) on the Schanz pins, with the universal joint locked, leaving the rotational joint open ( Fig. 58.15B ). Make the tibial osteotomy with a single cut perpendicular to the plane of maximal deformity (see Fig. 58.15B ). If lengthening is not needed, hold the saw at an angle of 30 to 45 degrees in the coronal plane to allow enough bone on either side of the cut to overlap and be lagged together.
If more lengthening is needed, the exact amount, in millimeters, to be obtained from axial lengthening already has been determined by preoperative planning. Obtain this length by decreasing the angle between the osteotomy and the axis of the tibia in the coronal plane so that the bones can slide apart lengthwise at the cut while remaining in contact. The angle of the cut in the coronal plane is determined preoperatively and is marked on the bone with a marking pen and angle templates from the angled blade plate instrument set (Synthes USA, Paoli, PA). Rotate the saw to this angle in the coronal plane and make the tibial cut accordingly. Cuts made at angles of less than 20 degrees to the coronal axis are impossible to perform.
As the femoral distractor is lengthened, the lengthening translates into angular correction. Leaving the rotational joint open (see Fig. 58.15B ) allows simultaneous correction of the multiplanar deformity by rotating the two tibial segments around an axis perpendicular to the cut surface. Continue this correction until the two Schanz pins are parallel ( Fig. 58.15C ).
If the cut is not perfect, additional bone can be shaved from the cut surfaces to correct alignment.
If axial lengthening is not required, place a lag screw perpendicular to the cut surface and tighten it. If axial lengthening is required, use a clamp (bone reduction forceps with pointed tips) to hold the two cut surfaces together until the angular correction has been obtained and then lock the rotational joint of the distractor. Additional lengthening of the distractor now lengthens the tibia axially. Gently loosen the bone clamp, but hold it in place to allow sliding in the axial plane while preventing translation and loss of angular correction. If somatosensory evoked potentials change before axial lengthening is completed, stop the lengthening and reverse it until the potentials return to baseline.
When lengthening is completed, tighten the clamp, lock the distractor joints, and obtain anteroposterior and lateral radiographs. Superimpose these radiographs on the preoperative drawings and on the radiograph of the normal leg and make modifications as needed.
When the alignment and length are satisfactory, place a lag screw perpendicularly across the osteotomy ( Fig. 58.15D ).
Contour a narrow 4.5-mm dynamic compression plate and place it as a neutralization plate ( Fig. 58.15E ).
Shave the bone and place the bone shavings as grafts around the osteotomy as needed.
If an equinus contracture developed as the bone was lengthened, perform a Z-lengthening of the Achilles tendon.
Remove the distractor, close the wound over a drain, and apply a bulky dressing and a below-knee posterior splint.
Range of motion of 0 to 90 degrees is begun immediately after surgery in a continuous passive motion machine. The patient is allowed out of bed on the first postoperative day. The drain is removed when less than 10 mL of drainage occurs in an 8-hour period, usually by the second day after surgery. The dressing is removed at 3 days, and if the wound appears satisfactory, a below-knee non–weight-bearing fiberglass cast is applied and touch-down weight bearing is allowed. The sutures are removed at 10 to 14 days, and the cast is changed. At 10 to 12 weeks, the cast is removed and a removable tibial brace is fitted. If bridging trabeculae across the osteotomy are visible on anteroposterior and lateral radiographs, partial weight bearing is allowed and is progressed as tolerated. Gait-training, range-of-motion, and strengthening exercises are begun. At the end of 16 weeks, if the tibial osteotomy seems to be healed clinically and radiographically, the brace is discontinued and activities of daily living and full weight bearing are encouraged. The patient is examined every 6 months for 2 years. The plate is removed if requested by the patient because of pain but not before 12 months after surgery.
Russell et al. described a clamshell osteotomy in 10 patients for treatment of complex femoral and tibial diaphyseal malunions, in which the malunited segment is transected perpendicular to the normal diaphysis proximally and distally and the transected segment is wedged open by osteotomy much like opening a clamshell. An intramedullary rod is used to anatomically align the proximal and distal segments of the diaphysis. Pires et al. expanded the use of the clamshell osteotomy to facilitate intramedullary nailing in acute fractures of long bones with preexisting deformity. Contraindications for this technique include an unsuitable soft-tissue sleeve for open exposure, a metaphyseal malunion, intramedullary osteomyelitis, absent medullary canal, morbid obesity, open physes, and lengthening of the tibia by more than 3 cm. We have not used this technique.
(RUSSELL ET AL.)
Position the patient supine with both lower extremities included in the operative field. A tourniquet is not used.
Make a lateral incision along the fibular shaft at the planned level of the proximal transverse component of the tibial osteotomy. Perform a fibular oblique osteotomy to obtain complete freedom in repositioning the tibia after the osteotomy.
Use a transpatellar or medial parapatellar tendon entrance to the previously defined safe zone for the tibial rod starting point. Take care to ensure an appropriate entrance angle into the proximal tibial segment. Open the proximal tibial segment with a threaded wire over which an opening reamer is passed. No attempt is made to ream the proximal tibia at this time.
To expose the osteotomy site, make a longitudinal incision over the anterior compartment one fingerbreadth lateral to the tibial crest along the proposed longitudinal osteotomy site.
Translate the anterior compartment musculature posteriorly to allow for an extraperiosteal exposure of the lateral aspect of the malunited segment. Only the anterolateral portion of the tibia is exposed.
With radiographic guidance, localize the positions of the proximal and distal transverse osteotomies and place a Kirschner wire perpendicular to the anatomic axis to guide the osteotomies ( Fig. 58.16A ).
Create the clamshell component of the osteotomy parallel to the medial tibial face, beginning just posterior to the anterolateral subcutaneous prominence of the tibia and aiming in a posteromedial direction ( Fig. 58.16B ).
Use a 3.5-mm drill bit to create the path for the longitudinal osteotomy with the goal of creating a bicortical uniform plane of stress risers ( Fig. 58.17 ). Only osteotomy of the near cortex is accomplished with an osteotome using the drill holes as a guide. Use a sagittal saw to create the transverse proximal and distal osteotomies.
Split the far cortex of the osteotomized segment parallel to the medial face with the use of an osteotome and laminar spreader. Separate the longitudinal osteotomy of the intercalary segment with a laminar spreader; the posterior cortex is hinged on the periosteal sleeve. If the posteromedial cortex does not open easily, then use an osteotome to cut the posteromedial cortex and then the laminar spreader to open the osteotomy.
Place the limb over a radiolucent triangle and pass the guidewire from the proximal tibial segment through the osteotomized segment into the distal segment with the aid of fluoroscopic guidance. Measure the length of the guidewire. Make sure the entrance angle and the ending point in the distal segment are in the center of the tibia on both the anteroposterior and lateral fluoroscopic images.
Before reaming, the anterior muscular compartment is allowed to drape over the cortex to preserve the bone fragments produced by subsequent reaming at the osteotomy sites. Ream the proximal and distal segments until cortical chatter is noted. The reaming should result in a deposit of bone fragments at the osteotomy gap sites.
Push the reamer through the clamshell segment to protect the neurovascular structures and to avoid binding against the osteotomized fragments. Continue reaming in 0.5-mm increments until cortical chatter is obtained. A tibial rod measuring 1 mm less in diameter than the final reamer is selected.
Pass the rod and accomplish proximal interlocking. Remove the jig from the proximal aspect of the tibial nail and remove the limb from the triangle and place it flat on the operating table.
The sagittal and coronal plane corrections have been accomplished at this point and only length and rotation need to be corrected ( Fig. 58.18 ). Have an assistant apply manual traction or use a femoral distractor or an external fixator to correct length and rotation. Place the distal interlocking bolts with the use of fluoroscopic guidance.
Retract the anterior compartment posteriorly from the lateral part of the tibia to inspect the osteotomy site. Fill the gaps with the bone fragments left from reaming. For gaps of more than 1 cm, demineralized bone matrix or autogenous bone graft can be used. Make sure that there is no space left between the osteotomy fragments and the intact proximal or distal parts of the tibia.
Loosely approximate the fascia over the anterior compartment. However, if there is concern that excessive swelling may cause a compartment syndrome, do not close the anterior compartment.
Close the extensile approach with the use of the Allgöwer modification of the Donati technique with careful soft-tissue handling.
Monitor the patient for signs of compartment syndrome. Intravenous cephazolin is administered for 24 hours postoperatively. The patient may begin touch-toe weight bearing on the first postoperative day using crutches. Russell et al. recommended prophylactic heparin until the patient is discharged from the hospital. Weight bearing is advanced as the osteotomy healing progresses with full weight bearing allowed by 12 weeks ( Fig. 58.19 ).
If a fracture of a tibial condyle heals with moderate-to-severe displacement, the change in position of its weight-bearing surface produces an increase in the joint space, a relaxation of some of the knee ligaments, a valgus or varus weight-bearing alignment, and frequently some rotational deformity. Any such displacement must be corrected if a severe disability from traumatic arthritis is to be avoided. The procedure of choice for this type of malunion varies with the kind of fracture and the exact source of the disability. Before surgery, the lateral instability might seem to indicate that a ligament should be repaired; yet after correction of the bony deformity, the joint usually is stable.
If the disability is caused mainly by axial malalignment after depression of a condyle, the weight-bearing surfaces of the tibia usually do not need to be disturbed. Rather, a transverse subcondylar osteotomy combined with the insertion of a graft and internal fixation is indicated; this procedure is especially appropriate when the patient is of middle age, the malunion is of long duration, and the lateral displacement is not severe. In other instances, an oblique osteotomy through the old fracture is possible; the depressed condyle is elevated and fixed with a buttress plate and screws, and the defect is filled with bone grafts. This procedure is applicable to young patients after a fairly recent fracture. Sometimes the deformity of the condyle and the degeneration of the articular cartilage are so severe that reconstruction is impractical; an arthrodesis or arthroplasty is then usually indicated.
Begin an incision over the anterolateral aspect of the knee 2.5 cm proximal to the joint and extend it distally parallel with the shaft of the tibia for 7.5 cm.
Make an inverted-L–shaped incision across the lateral condyle and down the crest of the tibia; detach the origin of the extensor muscles and dissect the muscles subperiosteally from the bone.
Completely divide the bone by a transverse osteotomy at a point immediately distal to the tibial tuberosity.
Using a broad osteotome as a lever, tilt the upper fragment proximally and angulate the distal shaft medially; the normal transverse plane of the tibial condyles and the normal alignment of the extremity are largely restored.
Fill the wedge-shaped or cuneiform space created by the osteotomy with bone grafts. Make an anterior incision 7.5 cm long and 5 cm distal to the first incision and expose the shaft of the tibia; remove a free cortical graft to serve as a wedge (usually 1.9 cm wide and about 3.8 cm long). Set the graft on edge and, using an inlay, drive it tightly into the space beneath the lateral condyle. Insert around this graft cancellous bone from the opening in the tibia and a few shavings from the surface of the bone. No undue lateral motion should be possible after the procedure. A full-thickness iliac graft provides more stability, but removal of such a graft increases the complexity of the operation.
Stabilize the osteotomy as for a fresh fracture with a T-plate as a buttress.
Confirm the reduction with intraoperative radiographs.
A similar procedure can be used for malunited fractures of the medial condyle.
If the weight-bearing surface was comminuted at the time of fracture, elevation of only the depressed fragments produces a refracture through its articular surface and the fragments can be difficult to hold in position; even attempts to pry them into position usually lead only to crushing rather than to correction of the deformity.
The knee is held in extension and immobilized in a cast from the toes to the groin. At 2 weeks, the cast is removed and radiographs are obtained. If satisfactory stability of the osteotomy is obtained by internal fixation, range-of-motion exercises are begun. A cast brace can be worn if further protection is needed until the osteotomy has united. Union may be solid at 8 weeks, but direct weight bearing should not yet be allowed, lest the depression recur. Walking is permitted with crutches, and weight bearing is increased as tolerated, but the crutches must not be discarded for 1 month. Weight bearing and undue strain must be prevented until union of the grafted area is absolutely solid.
Expose the operative field as just described except that the incision must extend proximally far enough to expose the knee joint.
Examine the lateral meniscus, and if it is torn, treat it as described in Chapter 45 .
Dissect all scar tissue from between the tibia and the condylar fragment and denude their surfaces as far distally as possible.
Refracture the fragment at its base by inserting an osteotome in a proximal and medial direction.
Sever the soft-tissue attachments only at the line of fracture or as necessary to mobilize the fragment.
Drill a Knowles pin or Schanz screw into the fragment to use first as a lever to aid in reduction.
Drill a Kirschner wire into the fragment across the fracture and into the opposite tibial condyle.
Fix the fracture using AO techniques as for a fresh fracture.
Fill any residual defect with cancellous bone. Because in this type of fracture some bone substance is lost, perfect apposition and contour cannot be restored.
A similar procedure can be used for the medial condyle.
With the knee extended, a plaster cast is applied from the toes to the groin. If satisfactory stability has been achieved at 2 weeks, the cast is removed and a cast brace is substituted to begin controlled range-of-motion exercises. Walking also is permitted with crutches and a cast brace. If consolidation of bone is sufficient 12 weeks after surgery, the crutches and cast brace can be discarded.
Malunited Y-shaped fractures or malunited fractures of both condyles are approached from both sides and are corrected by the method of osteotomy and internal fixation for malunion of a single condyle described previously. The operation is extensive and usually should be chosen only as a preliminary procedure to restore the contour of the condyles for a future arthroplasty. Practical function rarely can be expected, unless the deformity is corrected within a few months after injury; even then, osteoporosis may make replacement of the fragments difficult.
Malunion of displaced fractures of the intercondylar eminence of the tibia can severely restrict knee extension because of impingement of the malunited fragment on the femoral intercondylar notch. Arthroscopic or open removal of the fragment, debridement, and open anatomic reduction and fixation have been recommended for treatment of this malunion. In patients with functionally stable anterior cruciate ligaments, arthroscopic notchplasty, in which the femoral notch is enlarged with a power burr until it can accommodate the prominent intercondylar eminence and allow full knee extension, can be performed. Panni et al. recommended as sparing a notchplasty as possible to achieve full extension. Arthroscopic notchplasty is described in Chapter 51 .
The symptoms of a malunited fracture of the patella are similar to those of advanced chondromalacia. Disability is proportionate to the amount of irregularity of the articular surface of the patella and of the roughening of the contiguous surface of the femur. For even a relatively recent malunion, patellectomy usually is the procedure of choice (see Chapter 54 ).
Malunion of one or both femoral condyles, as of the tibial condyles, distorts the articular surface of the knee; frequently, however, it produces a much more severe disability than does one of a tibial condyle. Malunion of the lateral femoral condyle can produce external rotation, flexion, and valgus deformities of the knee; malunion of the medial condyle produces internal rotation, flexion, and varus deformities.
Approach the joint through a lateral incision beginning 10 cm proximal to the knee and extending distally to 2.5 cm distal and slightly anterior to the head of the fibula.
Incise the iliotibial band, but avoid the peroneal nerve that passes over the head of the fibula.
Incise the vastus lateralis muscle and retract it anteriorly to expose the old fracture.
Open the capsule and synovial membrane so that the interior of the joint can be seen during reduction of the fracture.
Divide the bone as near the plane of the old fracture as possible, but protect the peroneal nerve.
Grasp the condyle with bone-holding forceps and place it in its normal position; drill two Kirschner wires through the fragment into the medial condyle, the wires crossing each other at an angle of 30 degrees. The wires should protrude through the opposite cortex.
Make two-plane radiographs to verify the position of the wires and of the fragment, then fix the fragment with AO cancellous screws.
To expose a malunited fracture of the posterior part of the lateral condyle, use the same lateral incision but carry the dissection posteriorly.
Expose the biceps tendon and peroneal nerve and retract them laterally and posteriorly.
Incise the posterolateral part of the capsule and expose the malunited fragment. The fragment always is displaced proximally and usually can be refractured from above downward.
After the fragment is freed, place it in position with a towel clip and fix it securely with two AO cancellous screws. If fixation is not sufficiently rigid, a buttress plate can be added.
Close the incision in routine fashion and apply a plaster cast from the toes to the groin with the knee in extension.
At 2 weeks, the cast is removed, a cast brace is applied, and active and passive exercises and physical therapy are begun; if fixation is firm, exercises can be done with overhead pulleys. An elevated shoe is fitted on the opposite side, and walking with crutches is permitted; however, weight bearing is not allowed until union is complete, usually at 8 weeks or more after surgery. Free motion of the knee in the brace is allowed at 10 to 12 weeks. The reduction can be partially lost unless every precaution is taken to preserve it.
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