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INFLUENCE OF SEGMENTAL CORRECTION ON THE INCIDENCE OF PIN TRACT INFECTIONS IN PATIENTS TREATED BY THE METHOD OF ILIZAROV
Atanasov Nenad, Poposka Anastasika, Samardziski Milan University Clinic for orthopaedic surgery, Medical Faculty University “St. Cyril and Methodius”- Skopje, Republic of Macedonia
Correspondence should be sent to: Dr. Nenad Atanasov m-r sci. Clinic for Orthopedic Surgery, Vodnjanska 17, 1000 Skopje Republic of Macedonia Tel./fax: +38923147626 E-mail:
[email protected]
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ABSTRACT
Introduction The most common complications associated with external fixation are perhaps the pin tract infections. They are often demonstrated as a superficial or deeper infection on the segment. Most of them respond well to local pin care and oral antibiotics. The aim of this study is to evaluate the influence of segmental distribution on the incidence of pin tract infections in patients treated by the method of Ilizarov. Material and methods The analysis was made on the results of 26 patients treated by the method of Ilizarov on the Clinic for Orthopaedic Surgery in Skopje from 2008 to 2013. 26 segments were analyzed from point of view of pin tract infections from which 14 lower legs (53,85%), 5 thighs (19,24%), 3 arms (11,54%), 2 knee joints (7,69%) and 2 talocrural joints (7,69%). No half-pins but only wires have been used. Pin tract infections were graded using the Saleh-Scott classification system. Results In the group of analyzed lower legs, 8 of 14 patients (57,14%) or 26 of 244 sites present infection signs (10,66%). In the group of analyzed thighs, 3 of 5 patients show pin tract infection signs (60%), or 16 of 66 sites. (24,24%). All the arms present pin tract infection, or 13 from 36 pin sites. (36,11%). In the two analyzed knee joints the infected sites are presented by 14,28%, whereas in the two talocrural joints infection is determined with 3,57%. Conclusion Although differences in incidence of pin tract infections in different segments were detected, most pin tract infections were mild and successfully managed by local treatment and administration of oral antibiotics only. There was neither change in the method of stabilization, nor removal of a wire due to prolonged infection. Key words: pin tract infection, incidence, Ilizarov method
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INTRODUCTION
The compression-distraction method by Ilizarov means a revolution in the field of limb lengthening and deformity correction of segments and extremities. Bone fixation using a circular frame and transfixing tensioned wires provides not merely multiplanar stability during the lengthening process, but a possibility of flexible correction of various isolated and combined complex deformities on certain segments as well. (figure 1) Nowadays, the tendency of accomplishing the Ilizarov apparatus is obvious through use of so-called hybrid systems for external fixation, with a combination of standard elements from the basic set of Ilizarov on one side, with typical elements of some other external fixation systems on the other side. In that manner, a simultaneous use of tensioned wires with half pins is not a rare occasion anymore. The reasons for use of these types of combined external fixation are not determined only by the caution for the anatomic structures on the segments, e.g. extremities during the surgical insertion, but are frequently based on the results of serious biomechanical analyses towards the effects of external fixation of the extremities. Besides the positive clinical effect of using the Ilizarov method, various types of complications and side effects in different stages of the treatment are to be expected. Among the most common complications are the so-called pin tract infections. They are often associated with external fixation and demonstrated as a superficial or deeper infection on the treated segment or even as an osteomyelitis. Some of the signs of pin track infection are erythema, exudation, pin loosening, elevated local temperature, pain etc. The incidence of pin tract infections varies in different institutions and in some reports reaches to 50%.[1] The consequences of pin tract infections can range from trivial to severe. Nevertheless, most of them respond well to local pin care and oral antibiotics, excluding the cases of initial failures in insertion of pins and wires, inappropriate angles of insertion between the wires on each ring, inadequate tensioning of wires, inadequate wire and pin dimensions etc. The purpose of this study is to determine the influence of the segmental distribution on the incidence and severity of pin tract infections in various groups of patients, as well as to present the measures to minimize them throughout the whole process of treatment by the method of Ilizarov.
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Figure 1: Bone fixation using an Ilizarov
circular frame and transfixing tensioned wires providing multiplanar stability during limb lengthening and a possibility of flexible correction of various isolated and combined complex limb deformities
MATERIAL AND METHODS
In this study, the results of 26 patients treated by the method of Ilizarov on the Clinic for Orthopaedic Surgery in Skopje in the time period from 2008 to 2013 were analyzed. The age distribution was from 8 to 61 years with a mean age of 32,65 and SD 17,43. 16 of the patients were males and 10 females. 26 segments were analyzed from point of view of pin tract infections from which 14 lower legs (53,85%), 5 thighs (19,23%), 3 arms (11,54%), 2 knee joints (7,69%) and 2 talocrural joints (7,69%). In the group of fourteen treated lower legs, in seven cases surgical lengthening has been performed because of segmental shortening, in six of them because of congenital hypoplasia, whereas in one case the shortening have been caused by a sequelae of poliomyelitis. The rest of seven lower legs involved one fracture, two posttraumatic non unions and four infected non unions. In the group of five treated thighs, in two cases surgical lengthening has been performed because of congenital femoral shortening, two patients were treated because of femoral fractures, and in one case infected non-union was a reason for performing an Ilizarov method of treatment. The group of three treated arms was consisted of one fracture, as well as of two posttraumatic non unions. One of the knee arthrodeses using the apparatus of Ilizarov was performed after a failure in revision total knee arthroplasty because of septic loosening, and the other followed a resection of tumour in the distal femur. The first compression arthrodesis of the ankle joint was performed in an adult female and was combined with a correction of severe inveterated deformity as a consequence of non treated equinovarus deformity in childhood, and the second was performed because of an inadequately treated comminuted fracture of distal tibia. In all the patients included in this study, no half-pins but only wires have been used. Intraoperatively, the wires were inserted using a power drill at a slow speed with a removal of the drill once the wire exited and use of a mallet to finish the contact 491
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between the wire and the ring on the opposite side. The wires were consequently tensioned using a wire tensioner. At the end of the operative procedure, gauzes with betadine in form of squares were placed on each pin site and an occlusive dressing was used around. 48-72 hours postoperatively, the whole region around the pin sites was left uncovered. An additional use of gauzes was necessary only in rare cases of exudates on the pin sites. The condition of each pin site was recorded daily, and a crust removal was performed if necessary. Pin site care was accomplished by local use of bacitracin-neomycine antibiotic spray which meant not merely a local prevention of pin site infection but also helped in maintaining of dry pin sites. A single preoperative parenteral dose of Ceftriaxon, which was continued postoperatively for 72 hours usually was sufficient in the general antibiotic treatment of the patients. The use of oral antibiotics was needed only in cases of development of pin site infection after the patients were discharged. Since no skin tension was detected in our patients, there was no need of release of the skin or subcutaneous tissue. In the period of lengthening there was a daily visiting of patients whereas in the stage of bone consolidation and remodelling the patients were followed up weekly, till the removal of the external frame.
The infected sites were graded according to Saleh-Scott classification system (1992): Grade 0–No problems Grade 1–Responds to local treatment, increased cleaning, and massage Grade 2–Responds to oral antibiotics Grade 3–Responds to intravenous antibiotics or pin releases Grade 4–Responds to removal of the pin Grade 5–Responds to local surgical curettage Grade 6–Chronic osteomyelitis RESULTS A total number of 26 patients with 201 wires were analyzed in this study. Since a transfixing wire has two pin sites, 402 pin sites were registered. Infection rate was assessed as a percentage of the number of pin sites as well as a percentage of the number of patients. Of the 26 patients analyzed in this study, in 16 of them (61,53%) sings of pin tract infections were detected. The number of pin site infections in each patient varied from zero to seven with a mean of 2.3 infections per patient. Sixty of 402 wire sites became infected, each wire having two sites of possible infection, so the total pin site infection rate was 14,92%. The majority of pin site infections occurred in the stage of bone consolidation (68,75%). According to segmental distribution, 14 lower legs, 5 thighs, 3 arms, 2 knee joints and 2 talocrural joints were analyzed for pin site infection. (figure 2)
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7.69% 7.69% 11.53%
53.84% 19.24%
lower legs
thighs
arms
knee joints
talocrural joint
Figure 2: Segmental distribution of the clinical material
In the group of lower legs 8 of 14 analyzed patients (57,14%) presented clear signs of infection. In the group of analyzed thighs, 3 of 5 patients showed signs of pin tract infection (60%). In all arms treated by the method of Ilizarov there were signs of pin tract infection, (100%). In one of the analyzed two knee joints with compressive arthrodesis by Ilizarov there was a pin site infection (50%), whereas in the treated two talocrural joints pin site infection was obvious in one patient (50%) (table 1) SEGMENT
WHOLE NUMBER OF PATIENTS
PATIENTS WITH PIN INFECTIONS
%
lower leg
14
8
57.14
thigh
5
3
60
arm
3
3
100
knee joint
2
1
50
talo-crural joint
2
1
50
Table 1: Segmental distribution of patients with signs of pin infections
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From the point of view of infected entering and exiting points of wires, as a percentage of the total number of pin sites for each segment separately, in the group of 14 lower legs, 26 out of the total number of 244 pin sites showed signs of pin infection.(10,66%) In the group of 5 analyzed thighs, 16 from 66 pin sites became infected, (24,24%) whereas in the group of treated arms, 13 sites out of the whole number of sites in this group (36) were registered as sites with clear signs of infection.(36,11%) The analysis in the two treated knee joints revealed pin site infection on four sites, which meant 14,28% from the total number of sites in this group. In the two treated talocrural joints, infection was proved on one pin site, which revealed a percentage of 3,57, considering the whole number of analysed sites on this segment (28).
WHOLE NUMBER OF PIN SITES
NUMBER OF INFECTED PIN SITES
%
lower leg
244
26
10.66
thigh
66
16
24.24
arm
36
13
36.11
knee joint
28
4
14.28
talo-crural joint
28
1
3.57
SEGMENT
Table 2: Segmental distribution of pin site infections as a percentage of the number of pin
sites
The incidence of pin tract infections in the metaphyseal region was 73,33%, or 44 out of the whole number of 60 infected sites, which means a rather higher percentage compared with the same percentage in the diaphyseal regions presented as 26,66%, or 16 out of the total number of 60 infected sites, respectively. Analysing the number of patients, in 15 out of 16 patients with pin infection, part of the wires were inserted exactly in the metaphyseal regions, which presented a statistically significant influence on the incidence of pin tract infections. (p
