| | Treatment of severe fractures of the calcaneus by reconstruction arthrodesis using the Vira® System: Prospective study of the first 37 cases with over 1 year follow-upAccepted 17 March 2010. Abstract PurposeTo study the surgical applicability and clinical results of the Vira® System in treatment for severe fractures of the calcaneus. MethodsA total of 37 acute intra-articular fractures of the calcaneus treated by reconstruction and primary fusion with the minimally invasive Vira® System. Of them, 33 patients were analysed over a 2-year period. All fractures were classified, according to the Sanders criteria, as grade IV. The mean age was 42.08 years. Four were bilateral fractures and three were open fractures. All the patients were evaluated, in a prospective manner, using the American Orthopaedic Foot and Ankle Society (AOFAS) scale, plain radiographs and CT scan studies. ResultsThe average AOFAS score 12 months after surgery was 75.43 points (SD: 13.9). In 31 cases, the result was considered good and very good, and in five and one case mild and poor. Most of the patients (81%) could wear normal shoes; the footprint and the alignment of the heel were considered normal in all cases but seven patients showed a mild valgus deviation. The Böhler angle improvement after surgery was significant (p =0.05) and it did not vary along the follow-up. Subtalar arthrodesis was achieved in all cases. Only one case needed bone grafting. Important post-surgical complications were not registered in this cohort. ConclusionsThe Vira® System is a useful option for the surgical treatment of severe fractures of the calcaneus, yielding good clinical and radiological results with a surgical procedure that is only minimally aggressive and has a low rate of complications. Modern surgical treatment for fractures is designed to reduce the bone fragments, while achieving congruence in the joints and stable fixation, which allows early mobilisation. In fractures of the calcaneus, the principles of osteosynthesis are perfectly applicable but, historically speaking, the results have been controversial.5 This was mainly due to technical difficulty, post-surgical morbidity and long-term results, which only differ slightly from those of functional treatment. It has been shown that an imperfect open reduction is considerably worse than functional treatment,25 because it is inefficient and there is a higher rate of complications. On many occasions, a calcaneus fracture is so comminuted that surgical reconstruction is either impossible or useless. In such cases, the surgeon can adopt a conservative attitude and then treat the sequelae, or take the initiative by performing a reconstruction of the shape of the calcaneus and subtalar arthrodesis at the outset. This procedure has been shown to be effective and to reduce the period of recovery; although it has been defended by many authors from Stulz et al.27 onwards, it has not been included in the usual treatment protocols.18 Recently, primary arthrodesis as an option for the surgical treatment of fractures of the calcaneus has received a major boost with the development of the Vira® System.19 This system permits reconstruction of the shape of the fractured bone, restoring functionality to the calcaneus–Achilles–plantar system, while also fixing the body of the talus to achieve subtalar arthrodesis. The surgical concept is minimally invasive and does not require bone grafts in most cases, because the arthrodesis is performed using the bone extracted from the housing of the nail. This system, designed by the authors of the present study, has been applied in patients diagnosed with severe intra-articular fractures of the calcaneus. The aim of our study is to review the results obtained in those first consecutive patients with more than 1-year follow-up, treated using the Vira® System, to evaluate its surgical applicability and clinical results. Patients and methodology  Thirty-seven acute fractures of the calcaneus were analysed in 33 male patients, who were treated with the Vira® System over a period of 2 years. The mean age of the sample was 42.08 years (confidence interval (CI) 95%: 37–43), the youngest patient being 16 and the oldest 60 years old. As many as 19 fractures affected the right side, and 18 affected the left side. Four were bilateral, and the vast majority were closed fractures (34 cases). The three open fractures consisted of two of grade II and one of grade III. The mechanical cause in all cases was high-energy trauma. Under the Essex–Lopresti classification, 32 fractures presented a depression of the talus–calcaneus joint surface, while five had a tongue fracture. According to Sanders's classification, all cases presented a grade IV CT fracture pattern. The computed tomography (CT) images were evaluated by the same orthopaedic surgeon and confirmed by a radiologist. We found the lower cortical intact in six cases, and in 13 cases there were fracture lines in the greater tuberosity. The operations on the 37 fractures of the calcaneus were performed an average of 6 days after the accident because of the surgical programme. All of the accident victims were manual labourers, and 15 of them worked in the building sector. On emergencies, 23 patients presented associated injuries (Table 1); in most cases, there were fractures of the spine and lower limb. Twenty patients (54%) were habitual smokers.  | Isolated calcaneus fracture patients | 19 | | | Bilateral calcaneus fractures | 8 | | | Spine fractures | 6 | | | Tibia and ankle fractures | 4 | | | Upper limb fractures | 7 | | | Craneoencefalic trauma | 1 | | | Proximal femur fracture | 1 | | | | |
Surgical technique The system comprises a nail for the greater calcaneal tuberosity, traversed by two cannulated (tubero-talar) screws, which, on entering the heel, thread into the latter and the body of the talus (Fig. 1). The body of the talus is the most dense and resistant cancellous bone in the body, and the nail affords solidity and support for the fractured calcaneus, allowing the tubero-talar screws to maintain the alignment and tension of soft parts achieved through instrumentation. In this way, it is possible to restore and maintain the anatomical relationship between the talus and skeletal structure of the heel, fixating and favouring subtalar arthrodesis by using the specific Vira® guide (Fig. 2). The patient was placed in the prone position with preventive ischaemia; the injured leg was raised higher than the healthy one to achieve a better radioscopic view. Before surgery, we performed reduction manoeuvres to close the fracture, using the technique published by Omoto and Nakamura,23 particularly in the cases where there was a greater degree of displacement. In the cases in which the inferior cortical of the calcaneus was broken and there was shortening of the bone, the guide wire was used in the talus head, by insertion from the inner aspect of the foot using radioscopy to locate the centre of the head of the talus. The needle stayed in the frontal plane, parallel to the joint interline of the ankle and in the axial plane, perpendicular to the axis of the foot. The guide needle was used in 22 cases. We made an external para-Achilles incision approximately 3-cm long, taking care not to damage the sural nerve, which runs through the pre-Achilles portion of the calcaneus. This approach exposes the superior aspect of the calcaneus and the posterior portion of the subtalar joint. Using a curette, we eliminated the cartilage from the subtalar surface of the subtalar and the chondral remains from the fractured surface of the calcaneus. The guide was adjusted to the greatest tuberosity using the manual screw at the end of the handle (Fig. 3(A)). Radiography was used to check the position, with the aid of the guide needles simulating the direction of the screws, which had been passed externally through the orifices of the arms of the guide. These needles define the position of the definitive screws. If they are not properly adjusted in the body of the talus, the guide has to be repositioned. The guide makes it possible to modify the axis of the calcaneus by turning the screw on the handle and applying movements of flexion and extension. The housing for the nail in the greatest tuberosity was made using a 10-mm drill, taking care to protect the Achilles tendon. Once the housing of the nail has been drilled, and before the implant is positioned, the bone extracted during the perforation is placed in the subtalar joint. In this series, only three cases required augmentation with autologous bone. With support from the guide, the pin was hammered into the channel that had previously been marked (Fig. 3(B)). With the nail in position on the guide, a small (2-cm) incision was made in the heel for the tubero-talar screws insertion. The guide needle was passed and the length of the screws was measured using the specific depth gauge. After the needle, we passed the cannulated 4.5-mm drill to insert the screws. These steps were repeated for the second screw. An example of a typical Vira® System application is described in Fig. 4, Fig. 5, Fig. 6. After inserting the implant, we sutured the wounds and applied a compressive bandage. It was not necessary to immobilise the ankle and foot, and the system allowed immediate partial support, depending on the surgeon's criteria and the patient's tolerance, even in bilateral cases. Informed consent The subjects for this study gave specific informed consent before the surgery. Pre- and post-surgical evaluation In all the patients operated upon, we carried out radiographic and clinical studies, using the AOFAS scale. The lateral projection permitted us to measure Böhler's tubero-articular angle, which determines the degree of ascent of the posterior tuberosity of the calcaneus. In the normal calcaneus, the posterior angle formed by the two lines lies between 25° and 40°. After surgery, this value indicates the degree of reconstruction. A CT scan was performed at 3 months after surgery in all cases to assess the subtalar fusion. Functional post-surgical assessment Twelve months after the operation, all 33 subjects were interviewed using a structured questionnaire reproducing the AOFAS scale. The interviews were conducted by a single interviewer (TSL). Changes in shoe-wear were also registered. Statistical analysis The criteria for assessment or dependent variables were the post-surgical Böhler angle and the result on the AOFAS scale. A paired Student's t-test was carried out to corroborate the increase in Böhler's angle after surgery. Similarly, the points on the AOFAS scale were compared with other relevant variables and possible associated dependent variables. This analysis was performed using variance analysis and Student's t-test for independent variables. Finally, we performed the same analysis taking the AOFAS score as a dependent variable in ranks (very good, good, average and poor). To do this, we compared the proportions using the chi-square test. Results Radiographic results The Böhler angle prior to the operation was extremely deficient. The comparison of means showed a statistically significant trend towards improvement (p=0.05), although this was clinically irrelevant (a mean increase of 5.26°). We have found a high correlation with the number of order of the case and Böhler angle reconstruction (p=0.01). Because of the learning and development curve, the later patients were found to have better reconstructions. The reconstruction postoperatively achieved did not vary at the end of follow-up. The Böhler angle up remains stable without any secondary displacement of the fracture, even in the cases with fracture lines in the greater tuberosity. The subtalar arthrodesis was achieved in all cases. The bony bridge obtained at the end of follow-up was greater than two-thirds of the posterior subtalar joint in 27 cases, between one- and two-thirds in seven cases and less than one-third in three cases. In one case, pre-Achilles ossification occurred which slightly limited the mobility of the ankle. Clinical complications Minor post-surgical complications occurred in three cases (8.1%), mainly mild problems with the surgical wound that cures by time. A major post-surgical complication was one deep infection in a case of open grade III fracture. This patient was treated by implant removal and antibiotics for resolving the infection. However, the clinical result at the end of follow-up was poor in this catastrophic case. Other complications that occurred include fat pad syndrome (four cases) and osteolysis at the tip of the screws in the presence of subtalar fusion (two cases). The AOFAS scores were quite independent of the occurrence or absence of complications. However, from the descriptive point of view, the AOFAS score was, on average, eight points higher when no complications were present. Instrumental complications On two occasions, surgery was hindered by problems with the instruments, and as far as their insertion was concerned, we saw that the direction of the screws was normal in 22 cases, while in the others, there were angles of convergence (three cases) or divergence (12 cases); blocking of the screws was complete on 33 occasions, incomplete in one screw on two occasions, and incomplete in both screws in two instances. The position of the nail in the major tuberosity of the calcaneus was correct in 23 cases, presented a superior protrusion on 10 occasions and an inferior one in four fractures. Again, the clinical result was independent of the implant situation, since statistical correlation was not found between the AOFAS results and instrumental complications. Discussion Surgical treatment of severe fractures of the calcaneus, when it is properly indicated and executed, offers major advantages in comparison with functional treatment.4, 6, 10, 20, 24 However, a Spanish study shows that up to half of the surgeons choose not to operate, and to accept consequences, in the case of Sanders grade IV fractures.22 According to Sanders,25 almost 60% of these patients require surgery in the mid- to long-term to treat the sequelae, which generally consist of secondary subtalar arthrodesis with or without correction of deformities. The reasons for this trend have not been described, but analysis of the everyday situation in health care reveals that, on the one hand, severe fractures of the calcaneus are often a secondary concern in patients with multiple trauma in whom other systemic and musculo-skeletal injuries take priority.1 In other cases with a single injury, the hospital team's lack of training in the difficult area of surgical reconstruction of the calcaneus tips the balance towards a conservative attitude, bearing in mind the inherent morbidity and unreliable clinical results of surgical procedures, particularly in cases of open reconstruction and internal fixation. There is a general consensus in the bibliography about the indications for surgical treatment. As with any other displaced intra-articular fracture, reconstruction and stable fixation are the most desirable surgical solutions. The majority of authors indicate this for fractures of Sanders grades II and III, reserving reconstruction and primary fusion for grade IV fractures. To date, no classification has been developed, which takes into account all the aspects, which may be present simultaneously in fractures of the calcaneus, which is why this study used the classification that is most widely applied in the literature. The Sanders classification is based on the CT image in the frontal plane, taken with the greatest possible displacement of the joint. This classification presents moderate inter-rater reliability.17 It divides the body of the calcaneus into four columns, using the lines that are correlated with the most frequent fracture lines. This classification does not consider the other CT sections and CT reconstructions, and may therefore fail to pick up other possible fracture lines. Nor does it take into account the degree of displacement of the fracture, the complexity of the fracture line, any osteochondral injuries, tendon entrapment or the state of the soft tissues affected by the energy of the trauma. For this reason, we may encounter fractures that could be classified as grade II which are nonetheless high-energy injuries with major displacement and affection of the cartilage and soft tissues. Ball et al.3 recently demonstrated that the viability of the joint cartilage declines after fractures of the calcaneus, which may cause post-traumatic degeneration of the latter in the mid- to long term. According to Allmacher et al.,2 the long-term result of treatment of fractures of the calcaneus is mainly conditioned by the degree of osteoarthritis of the subtalar joint, since early elimination of this joint leads to major disorders of gait, and of the neighbouring joints. However, most patients aged over 15, who undergo subtalar arthrodesis, have not been found to have significant or symptomatic disorders. For this reason, the sacrifice of the subtalar joint is a reasonable price to pay in the long term to prevent problems in this joint which, although it could be reconstructed satisfactorily using an aggressive approach, often degenerates because of post-traumatic chondrolysis or undergoes spontaneous ankylosis.15 In the view of Csizy et al.,7 the prognostic factors which favour late subtalar arthrodesis in displaced fractures of the calcaneus are, in order of importance, a negative Böhler angle, a patient who suffered the injury in the workplace, grade IV fracture and conservative treatment. There are few published studies on primary arthrodesis in calcaneal fractures,8, 9, 13, 21, 27 but those that exist are unanimous about the efficacy of this treatment and its good results. Thermann et al.28 assessed 17 patients with secondary arthrodesis, and obtained a mean of 69 points on the AOFAS scale, while in cases of primary arthrodesis, they found a mean of 88 points. These extraordinary results have not been established elsewhere. Current surgery is clearly developing according to the principles of keeping aggressiveness to a minimum, which obliges the surgeon to achieve a perfect technique, leaving a minimal scar to reduce postoperative pain, prevent complications, shorten the period of convalescence, facilitate physiotherapy and improve the aesthetic and, above all, functional results. In cases of fracture of the calcaneus, many attempts have been made historically to perform minimally aggressive surgery,12, 26, 30 but the results to date have not proven entirely satisfactory, except in case of tongue fractures. Our study was performed in a workplace setting, where fractures of the calcaneus are increasingly common, and primary arthrodesis is the most generally indicated treatment. Nonetheless, the issue of economic compensation conditions the results in the case of many injuries, and fracture of the calcaneus is no exception to this. Thornes et al.29 showed that in workplace patients, the results of functional or surgical treatment were no different because of this conditioning factor. Despite these circumstances, the results of the present study are very encouraging. Aktuglu and Aydogan1 have already emphasised the point that fractures of the calcaneus have a worse outcome in cases on multiple trauma than in isolated fractures. Our study brings out the effectiveness of the Vira® System to achieve subtalar arthrodesis, since failure only occurred in two cases. This easily excels the results reported in the literature, as well as our own experience with secondary subtalar arthrodesis. The osteogenic biological environment, which is favoured by the presence of a recent fracture, and the stabilising efficacy of the implant, may account for these excellent results, which reflect those obtained by earlier authors.21 The incidence of complications is low, particularly if we take into account the fact that we are looking at surgical treatment for severe calcaneal fractures, most of which were high-energy lesions, in a group of patients with a high percentage of smokers (59.5%). If we compare our results with those published for treatment using an extended approach and internal fixation,14, 11, 16 the Vira® System fulfils the objectives of all minimally invasive surgery, in that it is efficient, with a low complications rate and the operation is less aggressive. It is true that one deep infection was present in the cohort. In actual terms, it cannot be considered a complication of the technique because the patient sustained a grade III open fracture with a high risk of infection. In conclusion, despite the minimally aggressive technique, the Vira® System cannot be used in the case of open calcaneus fracture as are other implants for internal fixation. One crucial aspect when discussing an implant that is being developed is the rate of instrumental complications. We must bear in mind that this study includes the first patients operated on using this technique, and that some difficulties arose during the operations, which required modifications to the technique or even to the instruments used. Despite this, surgery was possible in all cases, even though the early operations were problematic because of the team's inexperience and the need to refine the instrumentation. The surgical technique developed in parallel to the learning curve, and the last cases in the present series clearly present better radiological results. Recovery of the Böhler angle, as a radiographic sign of the restoration of the shape of the calcaneus, followed a similar tendency: the later patients were found to have better reconstructions. The patients’ average values improved after surgery, although less than expected, and the results did not vary over time, which indicates that the system achieved stability. The incidence of implants with the position of the screws or the pin below the optimum position was high, although this did not influence the clinical results, and the improvement in the instrumentation greatly reduced this phenomenon in the later cases. The Vira® System is a new concept in calcaneal surgery, which uses the principles of reconstruction and primary fusion to provide a definitive solution for patients: it offers low aggression and complication rate combined with high clinical effectiveness. Conflict of interest One of the authors (FLOM) has a patent agreement with the manufacturer of the Vira® System. References 1. 1Aktuglu K, Aydogan U. The functional outcome of displaced intra-articular calcaneal fractures: a comparison between isolated cases and polytrauma patients. Foot Ankle Int. 2002;23:314–318. MEDLINE 2. 2Allmacher DH, Galles KS, Marsh JL. Intra-articular calcaneal fractures treated nonoperatively and followed sequentially for 2 decades. J Orthop Trauma. 2006;20:464–469. MEDLINE |
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a Jiménez Díaz Foundation, Madrid, Spain b Department of Orthopaedic Surgery, Centro de Prevención y Rehabilitación, Fremap Majadahonda, Madrid, Spain  Corresponding author. Tel.: +34 91 640 88 99/62 758 66 16.
PII: S0020-1383(10)00196-8 doi:10.1016/j.injury.2010.03.019 © 2010 Elsevier Ltd. All rights reserved. | |
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