Correction of complex lower limb deformities by the Ilizarov technique ...

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Jean-Claude Theis. Department of Orthopaedic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand. H Simpson and J Kenwright.
Journal of Orthopaedic Surgery 2000, 8(1): 67–71

Correction of complex lower limb deformities by the Ilizarov technique: An audit of complications Jean-Claude Theis Department of Orthopaedic Surgery, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.

H Simpson and J Kenwright Nuffield Orthopaedic Centre, Headington, Oxford, England.

INTRODUCTION ABSTRACT This is an audit of complications resulting from correction of complex lower limb deformities by the Ilizarov technique. 33 patients (40 bone segments) were reviewed and divided into 4 groups according to the type of surgery carried out: limb lengthening and/or correction of deformity, bone or joint stabilisation, treatment of nonunion or bone defect, angular and/ or rotation correction. Most minor complications were fixator specific. Pin tract infections were almost universal but responded well to oral antibiotics and rarely resulted in osteomyelitis. Major complications were procedure specific and more common in those patients who underwent leg lengthening, treatment for nonunion and bone transport. There was also a high incidence of nerve injury as a result of acute angular deformity correction. Despite the high complication rate the Ilizarov technique remains an effective tool for complex lower limb reconstruction surgery. Key words: lower limb deformities, Ilizarov technique, complications

Complications have plagued limb lengthening techniques since their introduction.1,3,4 The Wagner technique developed in the late 1960s has fallen into disrepute because of an unacceptably high complication rate5,7,19 particularly related to bone healing.2,13,16 De Bastiani6 and Ilizarov8,9,10 have done much to promote limb lengthening and reconstruction techniques based on biological bone and soft tissue regeneration under tension stress. They claim to have been able to reduce the bone healing problem11,12 and as a consequence have reported a relatively low complication rate as compared to the Wagner technique.6,14,18 The Ilizarov technique is able to address complex deformities (angular, rotation, bone loss) which can affect more than one limb segment in addition to leg length inequality. There are very few reports in the literature on the complications of complex limb reconstruction using the Ilizarov technique.15,17 We report the complications recorded during the early use of the Ilizarov technique for the correction of complex lower limb deformities.

Address correspondence and reprint requests to: Dr Jean-Claude Theis, Department of Orthopaedic Surgery, Dunedin School of Medicine, PO Box 913, Dunedin, New Zealand.

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MATERIALS

AND

Table 1 Cause of limb deformity

METHODS

This is a retrospective study of 33 patients treated for various lower limb deformities using the Ilizarov technique at the Nuffield Orthopaedic Centre, Oxford, England between 1990 and 1992. This represents the initial use of the Ilizarov technique at this institution. There were 23 men and 10 women aged between 2 and 86 years with a mean age of 26.5 years. 17 patients were less than 20 years old. For the purpose of this study all 33 patients were reviewed by one of the authors (JCT) who had not been involved in any of the operations. 40 limb segments were treated including 26 tibiae, 6 femurs, 2 knees and 6 ankles. The majority of limb deformities were post traumatic in origin (Table 1). All 33 patients had complex limb deformities (Figs. 1, 2) with 48 previous operations ranging from 0 to 5 (mean 1.5 procedures per patient). The patients were divided into 4 groups according to the operation code (Table 2). The mean time in the frame was 155 days corresponding to approximately 5 months, ranging from 76 to 596 days.

Figure 1 Patient with severe shortening and ankle deformity due to congenital fibular hemimelia.

Post traumatic

21

Failed joint surgery

8

Congenital

6

Miscellaneous

5 40 Table 2 Operation category

Operation category

Number of segments

Group 1 Limb lengthening and/or correction of deformity

15

Group 2 Bone or joint stabilisation

13

Group 3 Compression distraction (nonunion) or bone transport (bone defect)

7

Group 4 Angular and/or rotation correction

5 40

Figure 2 X-rays showing tibial shortening, absence of the fibula and severe ankle valgus.

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Correction of complex lower limb deformities by the Ilizarov technique

A complication was defined as any unexpected event leading to change of management during the course of the treatment or after frame removal. Complications were divided into the following categories: pins, fixator, bone, joints, muscle/tendons, nerves, vessels and miscellaneous. Pin site infections were graded as shown in Table 3. Table 3 Grades of pin site infection Grade 1

Responds to local treatment

Grade 2

Responds to local treatment and antibiotics

Grade 3

Responds to intravenous antibiotics

Grade 4

Responds to pin removal

Grade 5

Responds to pin removal and curettage

Grade 6

Chronic osteomyelitis

except one Grade 5) and 3 had broken wires on X-rays. There were 4 fixator problems requiring frame modification under general anaesthetic. Bone complications were recorded in 6 cases (2 premature consolidation treated by osteotomy, 3 delayed consolidation/nonunion treated by bone grafting in one case). Other complications included one knee subluxation, one extensor hallucis longus weakness, one severe depression and one deep venous thrombosis. Group 2 13 segments treated by simple bone or joint stabilisation resulted in 14 complications (0.9 per segment). Complications consisted of 12 pin problems (pin site infections mostly), one frame adjustment under general anaesthetic and one nonunion which required bone grafting. Group 3

RESULTS A total of 73 complications were recorded corresponding to an average of 1.8 complications per segment treated (Table 4). Table 4 Type and number of complications in the 4 operation categories G.2 (n=13)

G.3 (n=7)

G.4 (n=5)

Total

Pins

14

12

12

3

41

Fixator

4

1

Bone

6

1

Joint

1

Nerve

1

3

4

Miscellaneous

2

1

3

9

73

28

5 10

2

19 1

14

22

Seven segments treated with compression/distraction or bone transport resulted in 22 complications (3.2 per segment). 12 pin problems were recorded and 10 bone problems in the form of premature consolidation in 3 and delayed/nonunion in 7, of which 6 required bone grafting. Group 4

G.1 (n=15)

G.1 G.2 G.3 G.4

69

Lengthening ± correction of deformity Bone or joint stabilisation Compression distraction or bone transport Angular and/or rotational correction

Group 1 15 segments treated by lengthening and/or correction of deformity resulted in 28 complications (1.9 per segment). Almost all patients in this group had pin problems. 11 developed pin site infections (all Grade 2

Five segments treated by correction of angular and/ or rotational deformity resulted in 9 complications (1.8 per segment). Complications consisted of 3 pin problems and 2 bone complications in the form of premature consolidation requiring reosteotomy. Three peroneal nerve palsies, which recovered partially, and one deep venous thrombosis were also recorded.

DISCUSSION In this heterogeneous group of patients with complex lower limb deformities treated with the Ilizarov technique the rate of complications was high confirming the results by Velazquez et al.17 reported in 1993. Our study has shown that most minor complications are fixator specific. Pin track infections are almost universal with any type of external fixator but respond very well to oral antibiotics and rarely lead to osteomyelitis requiring pin removal. Any skin tension produced at the time of wire insertion or during lengthening and transfixation of large amounts

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of muscle increases the risk of infection. Regular pin site care, early release of surrounding soft tissues and intermittent oral antibiotics keeps the pin site problems to a minimum. Wire breakage occurs occasionally and can be avoided by careful wire selection and placement. Frame problems are not common and can be avoided by careful preoperative planning. Major complications requiring further surgery and/or leaving permanent sequelae are procedure specific. The number and type of major complications in this study varied according to the type of procedure. Group 1 had a significantly higher number of complications (1.9 per segment) as compared to the stabilisation group in the form of joint subluxation, muscle/tendon contracture, premature consolidation etc. Most of these problems seem to be related to the intrinsic risks of lengthening of soft tissues but premature consolidation can be avoided by careful corticotomy and timing of distraction. Group 2 had no major complications. Group 3 is a high risk group with an average of 3.2 complications per segment. The risks are mostly delayed consolidation and nonunion probably as a consequence of the underlying bone pathology (bone infection and/or necrosis) rather than intrinsic problems with the method or technique. In the case of bone defect an acute shortening procedure, if possible, is a better option than bone transport as bone healing is better. If bone transport is chosen then prophylactic grafting of the docking site should be considered. Group 4 has a high risk of nerve palsy (3 cases in this study) and acute correction of the deformity should be avoided. Also beware of premature

consolidation by careful calculation and timing of angular correction. This study has highlighted a high rate of complications but despite this the Ilizarov technique remains a powerful and effective tool in the correction and reconstruction of complex limb deformities which in the past would have led to amputation.

CONCLUSION Our analysis of complications following the use of the Ilizarov technique in the correction and reconstruction of lower limb deformities highlights potential problems with this particular technique. Certain problems identified were related to the surgeon’s learning curve, minor complications were intrinsic to the fixator and of no consequence whereas major complications were related to the difficulties of reconstructing severe limb deformities, including major leg length inequalities. We were pleased to find no neurovascular injuries related to pin placement and we believe that transfixing wires are safe if placed through recognised safe corridors. Pin site infection can be minimised by careful insertion and care. Biological and mechanical conditions should be optimised to avoid delayed bone formation and nonunion. We believe that there is a definite place for early docking site bone grafting in cases of bone transport. Premature consolidation can be avoided by choosing an appropriate latency period, rate and rhythm of distraction and acute deformity correction should not be used in order to prevent nerve injury.

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