Posttraumatic arthritis coupled with malunion of the calcaneus represents a disabling condition after displaced calcaneal fractures. Treatment is aimed at eliminating pain by fusing the affected joint(s) and realignment of the weight-bearing forces at the hindfoot to improve foot function and protect neighboring joints from the development of secondary arthritis.
Three-dimensional analysis of the deformity
Classification of the type of malalignment and additional pathologies (nonunion, necrosis, infection)
Precise preoperative planning
Staged treatment protocol based on the individual type of deformity and the number of affected joints
Correction of varus or valgus malalignment with wedge-shaped bone resection or bone blocks
Correction of loss of height with bone block distraction
Correction of lateral shift after fracture-dislocation with osteotomy along the former fracture plane
Correction of talar tilt through ankle revision and hindfoot realignment
Treatment of calcaneal nonunion by resection of the pseudarthrosis, correction of alignment and bone grafting
Balancing of the soft tissues (Achilles tendon lengthening, release of the peroneal tendons)
HISTORY/INTRODUCTION/SCOPE OF THE PROBLEM
Malunions of the calcaneus are most regularly seen after nonoperative treatment of displaced fractures and fracture-dislocations. However, residual deformities may also result from imperfect reduction and in rare cases nonunion or avascular necrosis may develop after technical problems with open reduction and internal fixation. The observed deformities are a direct consequence of the fracture pathology and frequently lead to disabling conditions.
The most frequent problem observed after calcaneal fractures is painful subtalar arthritis following from extensive damage to the cartilage at the time of injury or a residual step-off after intra-articular fractures. The eccentric loading of the calcaneus at the time of fracture and the pull of the Achilles tendon lead to varus or valgus malalignment of the calcaneal body if not treated adequately. The axial impact that produces calcaneal fractures regularly results in shortening and widening of the hindfoot. Breakdown of the relatively thin lateral wall produces lateral bulging with impingement and/or subluxation of the peroneal tendons, fibulocalcanear abutment, and sural or posterior tibial neuritis.
Two-part fracture-dislocations of the calcaneus are rare injuries and therefore likely to be overlooked in the acute clinical setting, especially because the lateral view may appear fairly normal at first sight with an apparently normal Böhler’s angle and only slight loss of height (see also Fig. 27-4 ). These severe fracture-dislocations sometimes are mistaken as distal (Weber type A) lateral malleolar fractures because the body of the calcaneus is displaced laterally and upward, thus dislocating the peroneal tendons and avulsing the superior peroneal retinaculum or causing a direct impaction of the distal tip of the fibula. If overlooked or reduced inadequately, these fractures have profound effects on foot function.
Any deformity of the calcaneus invariably leads to a malposition of the talus with tibiotalar impingement and—in more severe cases—talar tilt leading to ankle arthritis. While painful subtalar arthritis can be treated successfully with isolated subtalar arthrodesis, correction of the deformity is needed for any malalignment in order to salvage foot function and protect the adjacent joints from eccentric loading and thus secondary arthritis.
Frederick Cotton, who became famous for treating acute calcaneal frctures by closed reduction with hammer and sandbag (the “impaction method”), observed very precisely the disabling sequelae of malunited calcaneal fractures at the beginning of the 20th century. He stated that “Os calcis fractures … are of interest because they give so large a percentage of cripples and because these cripples are strong men as a rule in youth or vigorous middle age.” Furthermore, he noted “more and more a number of cripples untreated very often diagnosed as sprained ankles in the early weeks.” Unfortunately, to a lesser extent these observations are still valid today, especially with the unusual fracture-dislocations leading to a chronic lateral and upward shift of the calcaneus. Cotton, in 1903, was reportedly the first to use an extra-articular osteotomy to correct calcaneal malunion by using Gleich’s operation for acquired flatfoot first performed in 1892 and lengthening of the Achilles tendon. He also performed a generous decompression of the bulged lateral wall—if necessary through the lateral aspect of the subtalar joint—for relief of fibulocalcaneal abutment and peroneal tendon impingement, which he identified as a major source of pain and disability, and he resected symptomatic plantar heel spurs, altogether with impressive results. In his original report, seven of nine patients regained normal or “practically normal” function. At about the same time, Magnuson tried to achieve correction by closed manipulation of the malunited calcaneus and subsequent plaster immobilization.
Carr et al., in 1988, were the first to suggest subtalar distraction bone block arthrodesis for malunited calcaneus fractures to reestablish calcaneal height and relief of tibiotalar impingement, a method that has been successfully used by numerous authors since then. In 1993, Romash performed an intra-articular osteotomy along the former fracture line to correct the lateral and dorsal deviation of the calcaneal tuberosity by shifting it medially and plantarily. He supplemented this osteotomy by subtalar arthrodesis and bone-grafting of the resulting subthalamic defect. Huang et al. performed a vertical sliding osteotomy with subtalar fusion to correct shortening of the hindfoot after malunited calcaneal fractures and found better results than with in situ arthrodesis of the subtalar joint.
Stephens and Sanders classified calcaneal malunions as type I (lateral exostosis), type II (additional severe subtalar arthritis), and type III (additional varus/valgus malalignment). Treatment was tailored to the type of deformity: lateral wall decompression (with lateral joint resection in cases of isolated lateral arthritis) for type I, additional subtalar arthrodesis for type II, and additional Dwyer-type closing wedge calcaneal osteotomy for type III.
In the authors’ experience, preservation of the subtalar joint is rarely possible in calcaneal malunions requiring correction because any type of deformity is almost invariably accompanied by painful postraumatic arthritis of the subtalar joint. However, if arthrofibrosis of the subtalar joint is present after open reduction and internal fixation, hardware removal with extra- and intra-articular arthrolysis is carried out. The latter is done with open subtalar athroscopy allowing thorough assessment of joint quality.
Zwipp and Rammelt have distinguished five types of posttraumatic calcaneal malunions ( Fig. 27-1 ). Type I resembles subtalar joint incongruity with arthritis, but without deformity; type II, additional varus/valgus malalignment; type III additional loss of height; type IV, additional lateral translation of the tuberosity after fracture-dislocation; and type V, the most severe deformity resulting in additional talar subluxation producing talar tilt in the ankle mortise. All types of malunion may be complicated by nonunion or avascular necrosis of the calcaneus, which must also be taken into consideration when planning operative correction ( Table 27-1 ).
|Characterization of Malunion|
|I||Subtalar joint incongruity/arthritis|
|III||Additional loss of height|
|IV||Additional lateral translation|
|V||Additional talar tilt|
|A||Solid bony malunion|
Surgical correction of painful malunions strongly depends on the type of deformity. Type I malunions are treated with an in situ subtalar arthrodesis supplemented by lateral wall decompression if an exostosis is present.
Type II malunions are treated with a correctional subtalar arthrodesis. Correction of varus or valgus malalignment is achieved either with asymmetric resection of the subchondral bone or by inserting bone blocks that are tailored three-dimensionally to restore heel alignment. With severe deformity, a calcaneal osteotomy is added. In type III malunions, a bone block distraction arthrodesis is carried out to restore heel height in addition to varus or valgus correction. Additional procedures include lateral wall decompression, Achilles tendon lengthening, and extra-articular osteotomy of the calcaneus if there is gross malalignment in the sagittal or coronal plane. Type IV malunions require an osteotomy along the original fracture plane and reorienting arthrodesis mostly with bilateral approaches. The rare type V malunions require a third incision over the ankle joint and gradual correction of the talocalcaneal alignment with fusion.
If a nonunion is present, the fibrous pseudarthrosis is resected until viable bone becomes visible. Correction is then carried out in the same manner as after osteotomy. Avascular necrosis or osteomyelitis of the calcaneal body requires radical and extensive debridement with subsequent defect filling or—in cases of recalcitrant osteomyelitis—calcanectomy. Secondary reconstruction may require soft tissue coverage by composite flaps.
Preoperative workup includes a thorough physical examination of the patient and clinical assessment of gait function. Weight-bearing lateral and anteroposterior radiographs (dorsoplantar projection with the tube tilted 20 degrees toward the toes) of both feet supplemented by a hindfoot alignment view are obtained. A preoperative computed tomography (CT) scan with both feet placed in neutral in a standardized holding device is most useful in detecting the amount of nonunion, necrosis, and arthritis at the hindfoot and midfoot. It should always be done if an osteotomy is planned. For more complex reconstructions, CT-based planning software allowing virtual three-dimensional osteotomies appears useful.
Symptomatic posttraumatic arthritis of the calcaneocuboid joint is seen less frequently and to a lesser extent in calcaneal malunions than subtalar arthritis. It is rather observed after malunited mid-tarsal fracture dislocations. If the calcaneocuboid joint is identified as a source of pain—which is not always the case even with radiographic signs of arthritis—it should be fused at the time of realignment and subtalar fusion.
Realignment of the calcaneus with subtalar fusion is indicated in all cases of symptomatic deformities after the failure of conservative measures—like pain medication, alteration of shoewear, and activities. The patients should be aware that although considerable pain reduction and functional improvement may be achieved, with these salvage procedures full foot function cannot be regained.