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Congenital abnormalities of the foot and toes: part 1
7-k Fovi (1998) 8 l-8 ‘0 199s Harcourt Blace & Co Lrd
REVIEW ARTICLE
Congenital abnormalities of the foot and toes: part 1 W. J. W. Sharrard SUMMARY. Some of the most important deformities of the foot and toes arise from congenital abnormalities of the bones of the leg. This section is concerned with features of congenital absence of the fibula, congenital absence of the tibia and tibio-fibular diastasis.
INTRODUCTION Congenital deformities of the foot, that is deformities presenting at birth, arise from a number of possible causes. including defective development of the bones or joints of the ankle, foot or toes, modifications in the developmental changes in the shape of the foot during pregnancy, alterations in shape due to intrauterine posture or external pressure by the uterus or paralytic deformities arising in association with spina bifida, arthrogryposis or vertebral agenesis. In general, deformities arising in early intrauterine life, such as those due to defective bone formation or to very early paralytic lesions such as arthrogryposis, tend to be more severe and resistant to correction, whilst those due to postural lesions are less severe and more easily corrected. This chapter is concerned with congenital deformities other than talipes equinovarus and metatarsus varus, which will be considered in a separate paper.
CONGENITAL ABSENCE OF THE FIBULA (CONGENITAL LONGITUDINAL DEFICIENCY FIBULA, TOTAL OR PARTIAL) The fibula is the most frequently deficient long bone. The foot shows absence of the lateral one or two rays, or rarely, of the four lateral rays. Commonly the whole fibula is absent; less often the proximal or proximal and middle third of the fibula is absent, or the whole fibula is present but hypoplastic. Although there is no direct relationship between the absence of rays or the shape of the foot and the extent of fibular deficiency, a normal or near-normal foot is usually associated with the presence of a lateral malleolus, though there may be delay in the appearance of the lower fibular epiphysis and it may be displaced proximally to an extent severe enough to require a Syme’s Correspondence Road, Sheffield
to W. J. W. Sharrard, S 10 5DL; UK.
‘Uplands’.
140 Manchester
amputation.’ In 75’% of patients. there is shortening of the same femur and in 15”/0 of patients there is a major proximal focal femoral deficiency. The degree of shortening is not related to the extent of fibular deficiency.’ Clinical features Coventry and Johnson3 describe three types. In type I lesions (Fig. l), the mildest type, only one limb is affected with partial absence or hypoplasia of the fibula; the tibia is not bowed and there is minimal equinovalgus foot deformity but the foot may show tarsal synostoses. A slight discrepancy in limb length may require treatment. In type II lesions, the limb is moderately affected (Fig. 2). The lesion may be unilateral, or, less often bilateral, with complete or almost complete absence of the fibula. At birth there is anteromedial bowing of the tibia with a typical skin dimple over the apex of the bowing and a fixed equinovalgus deformity of the foot. The lateral one or two rays of the foot are absent and the other bones of the foot are hypoplastic. There is frequently tarsal coalition with secondary development of a ball-and-socket ankle. There is moderate or marked shortening of the limb. usually 7-12 cm in childhood and 12-15 cm in adult life. In type III lesions, the most severe cases (Fig. 31, the defect is bilateral and associated with proximal femoral deficiency or with reduction deformities in the upper limbs. Amstutz” and Lefort et al5 found that the shortening below the knee does not increase with growth. the same relative discrepancy in limb length compared with the normal limb being present in later childhood. The degree of tibia1 bowing (Fig. 4) tends to diminish with growth and operations to excise the fibular anlage do not alter it. In a detailed study of the pathological anatomy, Lefort et al6 found that the fibula was replaced by a fibrous band extending from the lateral border of the proximal tibia to the posterolateral aspect of the calcaneus. Distally. it is thick and
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Fig. S-Congenital absence of the fibula. There is absence of the lateral two rays and severe equinovalgus deformity of the foot. There is moderately severe anterior tibia1 bowing with an overlying skin dimple.
Fig. l-Congenital hypoplasia of the fibula (type I). There is absence of the fifth ray. Foot deformity is minimal, though some equinovalgus deformity required soft tissue correction and there is mild limb inequality.
Fig. 2-Congenital absence of the fibula. There is absence of the lateral two rays and moderate equinovalgus deformity of the foot. The tibia shows some anterior bowing wtth an overlying skin dimple. The lesion is unilateral with moderate inequality of limb length affecting both the tibia and the femur.
strong, and may produce a false lateral malleolus. This bone is attached firmly to the lower end of the tibia and to the postero-lateral surface of the talus and calcaneus by ligaments, aggravating the equinovalgus of the hindfoot. The foot is always abnormal in some degree, varying from a fully formed but smaller foot to one in which one, two or three lesser toes and their associated The Foot
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metatarsal and tarsal bones are absent (Fig. 4). The hindfoot shows very considerable limitation of movement which may be due to coalition of the tarsal bones, commonly between the calcaneus and the talus or, less often, between the talus, the navicular and the calcaneus (Fig. 5) or between the calcaneus and cuboid or the calcaneus and navicular bones. The articular surface of the distal end of the tibia faces posteriorly and the talus is flattened and hypoplastic (Fig. 6). The ossification of the tarsal bones is delayed. There is often a valgus deformity of the knee with hypoplasia of the lateral femoral and lateral tibia1 condyles, contracture of lateral soft tissues and antero-posterior instability. The peroneal muscles are usually present and pass to their normal insertions or, if the fifth toe is absent, the peroneus breyis is inserted into the calcaneus. The tendo calcaneus is short and thick. The anterior tibia1 artery is absent or reduced in size. The medial ligament of the ankle may be interposed between the articular surface of the medial malleolus and the talus, and may prevent replacement of the talus beneath the tibia. When the child starts to walk he bears weight on the medial malleolus. If a prosthesis is applied to the limb without correction of at least some of the deformity, pressure has to be borne on the inner and anterior aspects of the tibia and it is difficult to achieve comfortable weight-bearing. Treatment
In mild type I cases, without foot deformity, treatment is only needed for inequality of limb length, though it may be necessary to consider exploration of the lower end of the fibula and to excise any short ligamentous or anlage tissues. 0 1998
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Fig. LRadrographs of congenital absence of the fibula (A). (B) The trbia shows moderate antertor bowing and the foot hes m severe equmus and valgus so that the calcaneus lies posterior and lateral to the lower end of the tibia. There 1s delayed ossrfication of the tarsal bones The lateral two rays are absent.
Fig. 5-Congenital navicular associated
synostoses of the talus. with congenital iibular
calcaneus, hypoplasia.
cubotd
and
In more severe type II or type III unilateral lesions without major femoral deficiency, it is tempting to try to correct the foot deformity. If a correction of the foot is attempted, simple division of the tendo calcaneus and posterior capsulotomy of the ankle is always inadequate.j Vestigial fragments of fibula must be removed together with their fibrous attachments to the tarsus and the outer side of the leg, the peronei divided or lengthened and the tendo calcaneus lengthened by a Z-incision or sliding procedure. The capsule of the ankle must be divided fully and the synostosis between talus and calcaneus divided to correct valgus at the hindfoot. The lateral intermuscular septum and deep fascia should be removed. The medial ligament of the ankle may need to be removed from the joint if it is incarcerated in it. The tibia1 bowing usually needs to be corrected by an osteotomy. 0 1998 Harcourt Brace & Co. Ltd
The position is held by pins or by an external circular frame which can be used to obtain additional correction. Correction of this type should preferably be done between 1 and 2 years of age. The valgus deformity recurs very frequently because of the absent lateral malleolus and corrective operations may need to be repeated. To diminish the liability to recurrence, Gruca’s operation”,’ can be performed. in which a vertical osteotomy is made through the middle of the lower end of the tibia and the medial fragment is displaced upwards to allow the lateral portion of the tibia to lie on the lateral side of the talus. Stiffness of the ankle and foot is almost inevitable and, cosmetically and for shoe fitting, the foot is never comparable with a normal foot. Such a procedure may, however, be indicated in countries with limited prosthetic services or if the family completely rejects the idea of amputation. Although the initial result may appear to be acceptable the end result of attempts to retain the foot is almost invariably unsatisfactory.‘S,9 The foot is cosmetically and functionally unsatisfactory; the child has to wear surgical shoes and is not able to join in many sporting activities. At maturity the child almost always demands amputation. A Syme’s amputation, preferably at the age of 1 year, is the treatment of choice when the predicted shortening lies between 8.7 and 15 cm and the foot is defective and deformed. Tibia1 bowing can be corrected by tibia1 osteotomy which can be made at the same time as the amputation (Fig. 7). The operation in children is described by Davidson and Bohne.” The Foot (1998) 8, I-8
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Fig. 6-Tale-calcanea1 synostosls ball-and-socket ankle joint.
associated
with
fibular
hypoplasla.
(A),
(B) The talus is flattened
and there
is an early appearance
of a
Fig. 7-(A)
Radiograph of severe congenital absence of the fibula. (B) Radiograph of combined Syme’s amputation and tibia1 osteotomy fixed by a Kirschner wire.
A
An above-knee cuff tourniquet is applied. The amputation uses a single long posterior heel flap. The incision begins one fingers-breadth distal to the medial malleolus and passes across the front of the ankle at the level of the distal end of the tibia to a point laterally, where, in a normal child, the tip of the lateral malleolus would be sited. It then extends directly plantarwards and transversely across the The Foof
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sole of the foot to the starting point below the medial malleolus. When there is marked equinus deformity, the incision should be made sufficiently distally; if the flaps are too long they can always be trimmed back a little whereas flaps that are too short will require too much of the tibia to be removed and there is a risk of damage to the lower tibia1 growth plate. 0 1998
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Congenital abnormalities of the foot and toes The dorsal dissection passes immediately down to bone, dividing all structures with ligation of the anterior tibia1 vessels if they are present. Dissecting proximally along the dorsal aspect of the talus, the foot is placed in full equinus and the anterior capsule of the ankle is divided. The knife is passed between the talus and the medial malleolus to divide the medial ligament and the lateral ligament and any abnormal lateral fibrous structures are similarly divided on the lateral side. This enables the foot to be placed in even more equinus. A bone hook is placed at the back of the talus and the posterior capsule of the ankle is divided, keeping close to the bone to avoid division of posterior vessels. The posterior portion of the calcaneus is now reached and the insertion of the tendo calcaneus is divided from it, keeping close to the bone. The calcaneus is pulled forward and downwards with a bone hook and dissected superiosteally with a periosteal elevator preserving the fibrofatty tissue of the heel pad on its plantar surface until the plantar skin incision is reached. The foot can now be removed. The medial malleolus and the lowest part of the tibia is exposed to a level about 1 cm above the ankle joint. The articular cartilage is removed from the lower end of the tibia immediately distal to the epiphysis and the medial malleolus is excised. A thin slice of bone is removed from the medial side of the lower end of the tibia to avoid too bulbous a stump. The medial and lateral plantar nerves are identified in the plantar flap and divided proximal to the cut end of the tibia. Any excess tendons are removed and the posterior tibia1 vessels ligated. Any excessive subcutaneous fat is excised but some should be left to preserve the blood supply of the heel and to provide a cushion over the end of the bone. Before suture, the tourniquet is removed and any bleeding points coagulated. The wound is sutured in layers with two suction drains using interrupted sutures in the fascial layers and a subcuticular suture for the skin. Dogears at the ends of the suture line should not be removed lest they disturb the blood supply of the flap. To avoid posterior migration of the heel a Kirschner wire can be passed through the heel flap into the lower end of the tibia; the same wire can be used to fix a lower tibia1 osteotomy performed through a separate vertical incision. The stump is bandaged. The drains are removed after 24-48 h and the wound dressed after 7-10 days. The pin is left in situ for 3 weeks. Prosthetic fitting with a pylon is made immediately after this and a permanent prosthesis fitted after 3 months. Bilateral severe lesions are a definite indication for Syme’s amputation, particularly in girls;4,‘o-‘Z Davidson and Bohne”’ note that genu valgum which tends to develop with growth may require adjustment of the prosthesis and a medial stapling of the upper 0 1998
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tibia1 epiphysis or a tibia1 osteotomy. The appearance after limb fitting is very acceptable. Good athletic and psychological function is recorded by Herring, Barnhill and Gaffiiey’3,1” and excellent results in a long-term follow-up to adult life are described by Epps and Schneider.” Even when a Syme’s amputation would be the ideal treatment, the parents may not be able to accept an amputation until continued growth convinces them that a normal limb of reasonable length cannot be reconstructed. If possible, they should see and talk to the family of a child who has had a Syme’s amputation to discover how functionally satisfactory it is and to try to persuade them of its value compared with a severely abnormal foot. If there is a combination of absence of the fibula and proximal femoral deficiency with gross limb shortening, as much limb length needs to be preserved as possible, at least until the ultimate length of the whole limb is known. Correction of excessive tibia1 bowing by osteotomy combined with correction of valgus but leaving an equinus foot to fit into a prosthetic device is then preferable to a Syme’s amputation, at least as a temporizing measure.
CONGENITAL ABSENCE OF THE TIBIA (LONGITUDINAL DEFICIENCY, TIBIA, TOTAL OR PARTIAL) The deformity is the converse of that in congenital absence of the fibula and is much rarer. There may be complete absence of the tibia (Fig. 8) or the proximal part of the tibia may be present (Fig. 9). The deformity is often associated with other abnormalities such as proximal femoral deficiency or a congenitally short femur, bifid femur, abnormalities of the hand such as lobster-claw deformity or thumb abnormalities, abnormalities of the male gonads. deformities of the opposite foot, hernia or congenital heart disease. scoliosis, or congenital absence of the radius. Kalamchi and Dawelb recognize three types of deficiency: type I with total absence of the tibia; type II with absence of the distal part of the tibia and type III with distal deficiency and tibio-fibular diastasis. Clinical features At birth, there is a varus or calcaneovarus of the foot and a short limb. When there is complete absence of the tibia, the upper end of the fibula at first articulates with the distal end of the lateral femoral condyle. but within the first month of life it migrates proximally and laterally to the femur (Fig. 10) especially when the child begins to try to walk on the limb. There is a flexion contracture, sometimes with popliteal webbing, and gross lateral instability of the knee. There are dimples over the front of the flexed knee and over the prominent lower end of the fibula (Fig. 11). The knee extensor mechanism is often deficient with a The Foot
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Fig. 9-Radiograph at birth of partial absence of the left tibia and total absence of-the right tibia. On the left, the knee joint is normal but there is dislocation of the superior tibio-fibular joint with proximal displacement of the fibula. The left foot shows moderate varus deformity. On the right the fibula lies below the femoral condyles but will migrate proximally during the first 3 months of life.
Fig. S-Radiograph of complete absence of the left tibia. There IS flexron deformity of the knee and varus deformity of the foot. There is an associated congenital short femur.
Fig. IO-Bilateral complete absence of the ttbta. On the left the upper end of the fibula has migrated posterror and lateral to the lower end of the femur
Fig. 11-Congemtal complete absence of the tibia. There is severe flexion deformity of the knee and varus deformity of the foot. There are skin dimples over the lower end of the femur and the lower end of the fibula.
poor quadriceps and a small or absent patella. The foot is fixed in varus and is rigid. There is always congenital fusion of the talo-calcaneal joint, even though, radiologically, the two bones appear to be distinct. The foot may show augmentation (Fig. 12) varying from polydactyly to diplopodia,‘7 I8 the first metatarsal may be short and there may be missing medial rays. l6
When the upper part of the tibia is present, the knee is often normal (Fig. 13). If there is a knee flexion deformity it is less marked than in total absence of the tibia and there is usually adequate knee extensor activity. The fibula is not dislocated from the tibia or the femur at birth but it soon rides upwards, dislocating at the superior tibio-fibular joint (Fig. 9) and later, when walking begins, it may
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dislocate to the lateral side of the lower end of the femur. The tibia1 fragment may be moderately large with a well-developed upper tibia1 epiphysis or may be small with late ossification but its presence as a cartilaginous anlage is indicated by the normal development and width of the femoral metaphysis and normal ossification of the epiphysis.16” Magnetic resonance imaging may be of value in demonstrating the presence of an anlage. The lower femoral epiphysis may be normal or hypoplastic. Treatment Fig. 12-Congenital with two additional
absence of the tibia. There is augmentatron digits on the medial side of the forefoot.
Fig. 13-Congenital partral absence normal but the foot is m varus.
Fig. tibia. been been and later
of the trbra
The knee IS
l&Radtograph of reconstructron for total absence of the Amputation was refused. The proximal end of the fibula has replaced below the femoral condyles and the distal end has placed in a socket formed by removal of the body of the talus it is being held m position by a Kirschner wue. Three years the foot deformity recurred.
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In milder cases with no major abnormality above the knee and preservation of the proximal part of the tibia, it is sometimes possible to obtain a satisfactory leg and foot by removing the body of the talus, releasing tight soft tissues on the medial side of the ankle, and placing the distal end of the fibula into the socket in the calcaneus provided by removal of the body of the talus. The tibialis anterior and posterior tendons need to be transferred laterally. At a second procedure, the uppermost part of the fibula is removed, taking care not to damage the common peroneal nerve, and the shaft of the fibula is fused to the proximal tibia. Finally, leg length discrepancy and any residual malalignment is corrected during childhood by the Iliazarov technique.lg In spite of an initially adequate correction, the foot deformity almost always recurs and needs revision on one or two occasions during growth. Often, it is not possible to obtain a satisfactory position of the foot and, if it is severely deformed and rigid, it is better to opt for a tibio-fibular fusion with removal of the proximal part of the fibula first followed by a Syme’s amputation, provided there is no proximal femoral focal deficiency. The ideal time for operation is between age 6 and 12 months. When the tibia is completely absent, reconstruction is more difficult, since there is need to attempt to reconstruct the knee.‘” The procedure should be done below the age of 1 year and preferably under 6 months. There should not be gross abnormality above the knee, the quadriceps must be present, and there must not be congenital bowing of the fibula.” The presence of a significant fixed flexion deformity of the knee should lead to a suspicion that the knee extensor mechanism is deficient, which is a contraindication to the operation. The foot is amputated at ankle level and prosthetic fitting made as for a belowknee amputation, though with a hinge to protect the knee, or, if amputation is not acceptable to the parents, excision of the body of the talus and fibulo-calcaneal articulation (Fig. 14). If there is deficiency of the knee extension mechanism, a disarticulation through the knee within the first year of life is the best management. It is followed by fitting with a knee disarticulation prosthesis. The functional results are good,‘62J as are the long-term results.‘5 The Fuot(1998)
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CONGENITAL
TIBIO-FIBULAR
DIASTASIS
Congenital tibio-fibular diastasis was first described by Tuli and Varma in 1972$ since then, several further cases have been described.“,” It is characterized by a clinical triad of congenital talipes equinovarus, diastasis of the ankle and inequality of limb length. There are frequently other abnormalities, either in the same limb, such as an absent or dysplastic first ray, tarsal abnormalities or a hypoplastic femur, or lobster-claw hand, cardiac defects or imperforate anus. Radiographs confirm the diagnosis. BoseZ6 and Jones, Barnes and Lloyd-RobertP consider that the condition results from tibia1 hyoplasia. The child presents with a congenital varus deformity of the foot with a complete but short tibia, revealed by a relatively increased length of the fibula at the level of the ankle and with a lower tibio-fibular diastasis so that the talus subluxates proximally between the tibia and the fibula. Its importance lies in differentiating it from other forms of congenital talipes equinovarus, since treatment needs to be directed to correction of tibio-fibular inequality as well as to the foot deformity, which is very rigid. Tibio-fibular diastasis can be treated by corrective plaster-casting and calcaneal and talo-navicular osteotomy,” or by reconstruction of the ankle mortiseZ3 and correction of equinovarus deformity with later limb lengthening, but the long-term results are not known. Calcaneo-fibular fusion with a Boyd amputation,‘6 or a Syme’s amputation” seems to be a more reliable solution, especially if shortening is predicted to be more than 10 cm at maturity.
6
7
8
9
10. 11
12.
13.
14
15.
16. 17.
18.
19.
20.
21. REFERENCES 1 2.
3. 4. 5.
22.
Bohne W H 0. Root L. Hypoplasia of the fibula. Clin Orthop 1977; 125: 107-112. Hootnick D, Boyd N A, Fixsen .I A; Lloyd-Roberts G C. The natural history and management of congenital short tibia with dysplasia or absence of the fibula. A preliminary report. J Bone Joint Surg Br 1977; 59: 267-271. Coventry M B, Johnson E W. Congenital absence of the fibula. J Bone Joint Surg Am 1952; 34: 941-955. Amstutz H C. Natural history and treatment of congemtal absence of the fibula. J Bone Joint Surg Am 1972, 54: 1349. Lefort J, Carlioz H, Pere C. Aplasies du perone et malformations associees. A propos de 62 cas. Rev Chir Orthop 1976; 62: 621-634.
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23. 24.
25.
26.
Serafin J. A new operation for congenital absence of the fibula. Preliminary report. J Bone Joint Surg Br 1967; 49: 59-65. Thomas I H, Williams P E The Gruca operation for congemtal absence of the fibula. J Bone Joint Surg Br 1987; 69: 587-592. Wood W L, Zlotsky N, Westin G W. Congenital absence of the fibula. Treatment by Syme’s amputation - indications and technique. J Bone Joint Surg Am 1965; 47: 115991691. Westin G W, Sakai D N. Wood W L. Congenital longitudinal deficiency of the fibula. J Bone Joint Surg Am 1976; 58: 492496. Davidson W H, Bohne W H 0. The Syme amputation m children. J Bone Joint Surg Am 1975; 57: 905-909. Aitken G T Amputation as a treatment for certain lowerextremity congenital abnormalities J Bone Joint Surg Am 1959; 41: 1267-1285. Kruger L M, Talbott R D. Amputation and prosthesis as definitive treatment in congenital absence of the fibula. J Bone Joint Surg Am 1961; 43: 625-642. Herring J A, Barnhill B, Gaffney C. Syme amputation. An evaluation of the physical and psychological function in young patients. J Bone Joint Surg Am 1986: 68, 573-578. Fergusson C M, Morrison J D, Kenwright J. Leg-length inequality in children treated by Syme’s amputation. J Bone Joint Sum Br 1987: 69: 433436. Epps C H, Schmeder P L. Treatment of hemimelias of the lower extremity. Long-term results. J Bone Joint Surg Am 1989; 71: 273-277. Kalamchr A, Dawe R V Congenital deficiency of the tibia. J Bone Joint Surg Br 1985; 67: 581-584. Karchinov K. Congenital diplopodia with hypoplasia or aplasia of the tibia. A report of six cases. J Bone Joint Surg Br 1973; 55: 604611. Jones D, Barnes J. Lloyd-Roberts G C. Congenital aplasia and dysplasia of the tibia with intact fibula. J Bone Joint Surg Br 1978: 60: 31-39. de Sanctis N, Razzano E, Scognamiglio R. Rega A N. Tibia1 agenesis: a new rationale in management of type II - report of three cases with long-term follow-up. J Pediatr Orthop 1980, 10: 1988201 Brown F W. Construction of a knee joint in congenital total absence of the tibia (paraxial hemimelia tibia). J Bone Joint Surg Am 1965; 47: 695-701. Brown F W. Pohnert W H. Construction of a knee ioint in meromelia tibia (congenital absence of the tibia). A 15-year follow-up study. J Bone Jomt Surg Am 1972: 54: 1333. Loder RT, Herring J A. Disarticulation of the knee in children. J Bone Joint Sure Am 1987: 69: 1155-l 160. Tuli S M, Varma B. Cong&tal diastasis of the tibiofibular mortise. J Bone Joint Surg Br 1972: 54: 346-350. Garbarmo J L, Clancy M, Harcke H T, Steel H H, Cowell H R. Congenital diastasis of the inferior tibiofibular joint: a review of the literature and report of two cases. J Pediatr Orthop 1985: 5: 225-228. Onimus M. Laurain J M, Picard F. Congenital diastasis of the inferior tibiofibular joint. J Pediatr Orthop 1990; 10: 175-176. Bose K. Congenital diastasis of the inferior tibiofibular joint. Report of a case. J Bone Joint Surg Am 1976; 58: 886-887.
0 1998
Harcourl
Brace
& Co. Ltd
REVIEW ARTICLE
Congenital abnormalities of the foot and toes: part 1 W. J. W. Sharrard SUMMARY. Some of the most important deformities of the foot and toes arise from congenital abnormalities of the bones of the leg. This section is concerned with features of congenital absence of the fibula, congenital absence of the tibia and tibio-fibular diastasis.
INTRODUCTION Congenital deformities of the foot, that is deformities presenting at birth, arise from a number of possible causes. including defective development of the bones or joints of the ankle, foot or toes, modifications in the developmental changes in the shape of the foot during pregnancy, alterations in shape due to intrauterine posture or external pressure by the uterus or paralytic deformities arising in association with spina bifida, arthrogryposis or vertebral agenesis. In general, deformities arising in early intrauterine life, such as those due to defective bone formation or to very early paralytic lesions such as arthrogryposis, tend to be more severe and resistant to correction, whilst those due to postural lesions are less severe and more easily corrected. This chapter is concerned with congenital deformities other than talipes equinovarus and metatarsus varus, which will be considered in a separate paper.
CONGENITAL ABSENCE OF THE FIBULA (CONGENITAL LONGITUDINAL DEFICIENCY FIBULA, TOTAL OR PARTIAL) The fibula is the most frequently deficient long bone. The foot shows absence of the lateral one or two rays, or rarely, of the four lateral rays. Commonly the whole fibula is absent; less often the proximal or proximal and middle third of the fibula is absent, or the whole fibula is present but hypoplastic. Although there is no direct relationship between the absence of rays or the shape of the foot and the extent of fibular deficiency, a normal or near-normal foot is usually associated with the presence of a lateral malleolus, though there may be delay in the appearance of the lower fibular epiphysis and it may be displaced proximally to an extent severe enough to require a Syme’s Correspondence Road, Sheffield
to W. J. W. Sharrard, S 10 5DL; UK.
‘Uplands’.
140 Manchester
amputation.’ In 75’% of patients. there is shortening of the same femur and in 15”/0 of patients there is a major proximal focal femoral deficiency. The degree of shortening is not related to the extent of fibular deficiency.’ Clinical features Coventry and Johnson3 describe three types. In type I lesions (Fig. l), the mildest type, only one limb is affected with partial absence or hypoplasia of the fibula; the tibia is not bowed and there is minimal equinovalgus foot deformity but the foot may show tarsal synostoses. A slight discrepancy in limb length may require treatment. In type II lesions, the limb is moderately affected (Fig. 2). The lesion may be unilateral, or, less often bilateral, with complete or almost complete absence of the fibula. At birth there is anteromedial bowing of the tibia with a typical skin dimple over the apex of the bowing and a fixed equinovalgus deformity of the foot. The lateral one or two rays of the foot are absent and the other bones of the foot are hypoplastic. There is frequently tarsal coalition with secondary development of a ball-and-socket ankle. There is moderate or marked shortening of the limb. usually 7-12 cm in childhood and 12-15 cm in adult life. In type III lesions, the most severe cases (Fig. 31, the defect is bilateral and associated with proximal femoral deficiency or with reduction deformities in the upper limbs. Amstutz” and Lefort et al5 found that the shortening below the knee does not increase with growth. the same relative discrepancy in limb length compared with the normal limb being present in later childhood. The degree of tibia1 bowing (Fig. 4) tends to diminish with growth and operations to excise the fibular anlage do not alter it. In a detailed study of the pathological anatomy, Lefort et al6 found that the fibula was replaced by a fibrous band extending from the lateral border of the proximal tibia to the posterolateral aspect of the calcaneus. Distally. it is thick and
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Fig. S-Congenital absence of the fibula. There is absence of the lateral two rays and severe equinovalgus deformity of the foot. There is moderately severe anterior tibia1 bowing with an overlying skin dimple.
Fig. l-Congenital hypoplasia of the fibula (type I). There is absence of the fifth ray. Foot deformity is minimal, though some equinovalgus deformity required soft tissue correction and there is mild limb inequality.
Fig. 2-Congenital absence of the fibula. There is absence of the lateral two rays and moderate equinovalgus deformity of the foot. The tibia shows some anterior bowing wtth an overlying skin dimple. The lesion is unilateral with moderate inequality of limb length affecting both the tibia and the femur.
strong, and may produce a false lateral malleolus. This bone is attached firmly to the lower end of the tibia and to the postero-lateral surface of the talus and calcaneus by ligaments, aggravating the equinovalgus of the hindfoot. The foot is always abnormal in some degree, varying from a fully formed but smaller foot to one in which one, two or three lesser toes and their associated The Foot
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metatarsal and tarsal bones are absent (Fig. 4). The hindfoot shows very considerable limitation of movement which may be due to coalition of the tarsal bones, commonly between the calcaneus and the talus or, less often, between the talus, the navicular and the calcaneus (Fig. 5) or between the calcaneus and cuboid or the calcaneus and navicular bones. The articular surface of the distal end of the tibia faces posteriorly and the talus is flattened and hypoplastic (Fig. 6). The ossification of the tarsal bones is delayed. There is often a valgus deformity of the knee with hypoplasia of the lateral femoral and lateral tibia1 condyles, contracture of lateral soft tissues and antero-posterior instability. The peroneal muscles are usually present and pass to their normal insertions or, if the fifth toe is absent, the peroneus breyis is inserted into the calcaneus. The tendo calcaneus is short and thick. The anterior tibia1 artery is absent or reduced in size. The medial ligament of the ankle may be interposed between the articular surface of the medial malleolus and the talus, and may prevent replacement of the talus beneath the tibia. When the child starts to walk he bears weight on the medial malleolus. If a prosthesis is applied to the limb without correction of at least some of the deformity, pressure has to be borne on the inner and anterior aspects of the tibia and it is difficult to achieve comfortable weight-bearing. Treatment
In mild type I cases, without foot deformity, treatment is only needed for inequality of limb length, though it may be necessary to consider exploration of the lower end of the fibula and to excise any short ligamentous or anlage tissues. 0 1998
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Fig. LRadrographs of congenital absence of the fibula (A). (B) The trbia shows moderate antertor bowing and the foot hes m severe equmus and valgus so that the calcaneus lies posterior and lateral to the lower end of the tibia. There 1s delayed ossrfication of the tarsal bones The lateral two rays are absent.
Fig. 5-Congenital navicular associated
synostoses of the talus. with congenital iibular
calcaneus, hypoplasia.
cubotd
and
In more severe type II or type III unilateral lesions without major femoral deficiency, it is tempting to try to correct the foot deformity. If a correction of the foot is attempted, simple division of the tendo calcaneus and posterior capsulotomy of the ankle is always inadequate.j Vestigial fragments of fibula must be removed together with their fibrous attachments to the tarsus and the outer side of the leg, the peronei divided or lengthened and the tendo calcaneus lengthened by a Z-incision or sliding procedure. The capsule of the ankle must be divided fully and the synostosis between talus and calcaneus divided to correct valgus at the hindfoot. The lateral intermuscular septum and deep fascia should be removed. The medial ligament of the ankle may need to be removed from the joint if it is incarcerated in it. The tibia1 bowing usually needs to be corrected by an osteotomy. 0 1998 Harcourt Brace & Co. Ltd
The position is held by pins or by an external circular frame which can be used to obtain additional correction. Correction of this type should preferably be done between 1 and 2 years of age. The valgus deformity recurs very frequently because of the absent lateral malleolus and corrective operations may need to be repeated. To diminish the liability to recurrence, Gruca’s operation”,’ can be performed. in which a vertical osteotomy is made through the middle of the lower end of the tibia and the medial fragment is displaced upwards to allow the lateral portion of the tibia to lie on the lateral side of the talus. Stiffness of the ankle and foot is almost inevitable and, cosmetically and for shoe fitting, the foot is never comparable with a normal foot. Such a procedure may, however, be indicated in countries with limited prosthetic services or if the family completely rejects the idea of amputation. Although the initial result may appear to be acceptable the end result of attempts to retain the foot is almost invariably unsatisfactory.‘S,9 The foot is cosmetically and functionally unsatisfactory; the child has to wear surgical shoes and is not able to join in many sporting activities. At maturity the child almost always demands amputation. A Syme’s amputation, preferably at the age of 1 year, is the treatment of choice when the predicted shortening lies between 8.7 and 15 cm and the foot is defective and deformed. Tibia1 bowing can be corrected by tibia1 osteotomy which can be made at the same time as the amputation (Fig. 7). The operation in children is described by Davidson and Bohne.” The Foot (1998) 8, I-8
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The Foot
Fig. 6-Tale-calcanea1 synostosls ball-and-socket ankle joint.
associated
with
fibular
hypoplasla.
(A),
(B) The talus is flattened
and there
is an early appearance
of a
Fig. 7-(A)
Radiograph of severe congenital absence of the fibula. (B) Radiograph of combined Syme’s amputation and tibia1 osteotomy fixed by a Kirschner wire.
A
An above-knee cuff tourniquet is applied. The amputation uses a single long posterior heel flap. The incision begins one fingers-breadth distal to the medial malleolus and passes across the front of the ankle at the level of the distal end of the tibia to a point laterally, where, in a normal child, the tip of the lateral malleolus would be sited. It then extends directly plantarwards and transversely across the The Foof
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sole of the foot to the starting point below the medial malleolus. When there is marked equinus deformity, the incision should be made sufficiently distally; if the flaps are too long they can always be trimmed back a little whereas flaps that are too short will require too much of the tibia to be removed and there is a risk of damage to the lower tibia1 growth plate. 0 1998
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Congenital abnormalities of the foot and toes The dorsal dissection passes immediately down to bone, dividing all structures with ligation of the anterior tibia1 vessels if they are present. Dissecting proximally along the dorsal aspect of the talus, the foot is placed in full equinus and the anterior capsule of the ankle is divided. The knife is passed between the talus and the medial malleolus to divide the medial ligament and the lateral ligament and any abnormal lateral fibrous structures are similarly divided on the lateral side. This enables the foot to be placed in even more equinus. A bone hook is placed at the back of the talus and the posterior capsule of the ankle is divided, keeping close to the bone to avoid division of posterior vessels. The posterior portion of the calcaneus is now reached and the insertion of the tendo calcaneus is divided from it, keeping close to the bone. The calcaneus is pulled forward and downwards with a bone hook and dissected superiosteally with a periosteal elevator preserving the fibrofatty tissue of the heel pad on its plantar surface until the plantar skin incision is reached. The foot can now be removed. The medial malleolus and the lowest part of the tibia is exposed to a level about 1 cm above the ankle joint. The articular cartilage is removed from the lower end of the tibia immediately distal to the epiphysis and the medial malleolus is excised. A thin slice of bone is removed from the medial side of the lower end of the tibia to avoid too bulbous a stump. The medial and lateral plantar nerves are identified in the plantar flap and divided proximal to the cut end of the tibia. Any excess tendons are removed and the posterior tibia1 vessels ligated. Any excessive subcutaneous fat is excised but some should be left to preserve the blood supply of the heel and to provide a cushion over the end of the bone. Before suture, the tourniquet is removed and any bleeding points coagulated. The wound is sutured in layers with two suction drains using interrupted sutures in the fascial layers and a subcuticular suture for the skin. Dogears at the ends of the suture line should not be removed lest they disturb the blood supply of the flap. To avoid posterior migration of the heel a Kirschner wire can be passed through the heel flap into the lower end of the tibia; the same wire can be used to fix a lower tibia1 osteotomy performed through a separate vertical incision. The stump is bandaged. The drains are removed after 24-48 h and the wound dressed after 7-10 days. The pin is left in situ for 3 weeks. Prosthetic fitting with a pylon is made immediately after this and a permanent prosthesis fitted after 3 months. Bilateral severe lesions are a definite indication for Syme’s amputation, particularly in girls;4,‘o-‘Z Davidson and Bohne”’ note that genu valgum which tends to develop with growth may require adjustment of the prosthesis and a medial stapling of the upper 0 1998
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tibia1 epiphysis or a tibia1 osteotomy. The appearance after limb fitting is very acceptable. Good athletic and psychological function is recorded by Herring, Barnhill and Gaffiiey’3,1” and excellent results in a long-term follow-up to adult life are described by Epps and Schneider.” Even when a Syme’s amputation would be the ideal treatment, the parents may not be able to accept an amputation until continued growth convinces them that a normal limb of reasonable length cannot be reconstructed. If possible, they should see and talk to the family of a child who has had a Syme’s amputation to discover how functionally satisfactory it is and to try to persuade them of its value compared with a severely abnormal foot. If there is a combination of absence of the fibula and proximal femoral deficiency with gross limb shortening, as much limb length needs to be preserved as possible, at least until the ultimate length of the whole limb is known. Correction of excessive tibia1 bowing by osteotomy combined with correction of valgus but leaving an equinus foot to fit into a prosthetic device is then preferable to a Syme’s amputation, at least as a temporizing measure.
CONGENITAL ABSENCE OF THE TIBIA (LONGITUDINAL DEFICIENCY, TIBIA, TOTAL OR PARTIAL) The deformity is the converse of that in congenital absence of the fibula and is much rarer. There may be complete absence of the tibia (Fig. 8) or the proximal part of the tibia may be present (Fig. 9). The deformity is often associated with other abnormalities such as proximal femoral deficiency or a congenitally short femur, bifid femur, abnormalities of the hand such as lobster-claw deformity or thumb abnormalities, abnormalities of the male gonads. deformities of the opposite foot, hernia or congenital heart disease. scoliosis, or congenital absence of the radius. Kalamchi and Dawelb recognize three types of deficiency: type I with total absence of the tibia; type II with absence of the distal part of the tibia and type III with distal deficiency and tibio-fibular diastasis. Clinical features At birth, there is a varus or calcaneovarus of the foot and a short limb. When there is complete absence of the tibia, the upper end of the fibula at first articulates with the distal end of the lateral femoral condyle. but within the first month of life it migrates proximally and laterally to the femur (Fig. 10) especially when the child begins to try to walk on the limb. There is a flexion contracture, sometimes with popliteal webbing, and gross lateral instability of the knee. There are dimples over the front of the flexed knee and over the prominent lower end of the fibula (Fig. 11). The knee extensor mechanism is often deficient with a The Foot
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Fig. 9-Radiograph at birth of partial absence of the left tibia and total absence of-the right tibia. On the left, the knee joint is normal but there is dislocation of the superior tibio-fibular joint with proximal displacement of the fibula. The left foot shows moderate varus deformity. On the right the fibula lies below the femoral condyles but will migrate proximally during the first 3 months of life.
Fig. S-Radiograph of complete absence of the left tibia. There IS flexron deformity of the knee and varus deformity of the foot. There is an associated congenital short femur.
Fig. IO-Bilateral complete absence of the ttbta. On the left the upper end of the fibula has migrated posterror and lateral to the lower end of the femur
Fig. 11-Congemtal complete absence of the tibia. There is severe flexion deformity of the knee and varus deformity of the foot. There are skin dimples over the lower end of the femur and the lower end of the fibula.
poor quadriceps and a small or absent patella. The foot is fixed in varus and is rigid. There is always congenital fusion of the talo-calcaneal joint, even though, radiologically, the two bones appear to be distinct. The foot may show augmentation (Fig. 12) varying from polydactyly to diplopodia,‘7 I8 the first metatarsal may be short and there may be missing medial rays. l6
When the upper part of the tibia is present, the knee is often normal (Fig. 13). If there is a knee flexion deformity it is less marked than in total absence of the tibia and there is usually adequate knee extensor activity. The fibula is not dislocated from the tibia or the femur at birth but it soon rides upwards, dislocating at the superior tibio-fibular joint (Fig. 9) and later, when walking begins, it may
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dislocate to the lateral side of the lower end of the femur. The tibia1 fragment may be moderately large with a well-developed upper tibia1 epiphysis or may be small with late ossification but its presence as a cartilaginous anlage is indicated by the normal development and width of the femoral metaphysis and normal ossification of the epiphysis.16” Magnetic resonance imaging may be of value in demonstrating the presence of an anlage. The lower femoral epiphysis may be normal or hypoplastic. Treatment Fig. 12-Congenital with two additional
absence of the tibia. There is augmentatron digits on the medial side of the forefoot.
Fig. 13-Congenital partral absence normal but the foot is m varus.
Fig. tibia. been been and later
of the trbra
The knee IS
l&Radtograph of reconstructron for total absence of the Amputation was refused. The proximal end of the fibula has replaced below the femoral condyles and the distal end has placed in a socket formed by removal of the body of the talus it is being held m position by a Kirschner wue. Three years the foot deformity recurred.
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In milder cases with no major abnormality above the knee and preservation of the proximal part of the tibia, it is sometimes possible to obtain a satisfactory leg and foot by removing the body of the talus, releasing tight soft tissues on the medial side of the ankle, and placing the distal end of the fibula into the socket in the calcaneus provided by removal of the body of the talus. The tibialis anterior and posterior tendons need to be transferred laterally. At a second procedure, the uppermost part of the fibula is removed, taking care not to damage the common peroneal nerve, and the shaft of the fibula is fused to the proximal tibia. Finally, leg length discrepancy and any residual malalignment is corrected during childhood by the Iliazarov technique.lg In spite of an initially adequate correction, the foot deformity almost always recurs and needs revision on one or two occasions during growth. Often, it is not possible to obtain a satisfactory position of the foot and, if it is severely deformed and rigid, it is better to opt for a tibio-fibular fusion with removal of the proximal part of the fibula first followed by a Syme’s amputation, provided there is no proximal femoral focal deficiency. The ideal time for operation is between age 6 and 12 months. When the tibia is completely absent, reconstruction is more difficult, since there is need to attempt to reconstruct the knee.‘” The procedure should be done below the age of 1 year and preferably under 6 months. There should not be gross abnormality above the knee, the quadriceps must be present, and there must not be congenital bowing of the fibula.” The presence of a significant fixed flexion deformity of the knee should lead to a suspicion that the knee extensor mechanism is deficient, which is a contraindication to the operation. The foot is amputated at ankle level and prosthetic fitting made as for a belowknee amputation, though with a hinge to protect the knee, or, if amputation is not acceptable to the parents, excision of the body of the talus and fibulo-calcaneal articulation (Fig. 14). If there is deficiency of the knee extension mechanism, a disarticulation through the knee within the first year of life is the best management. It is followed by fitting with a knee disarticulation prosthesis. The functional results are good,‘62J as are the long-term results.‘5 The Fuot(1998)
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CONGENITAL
TIBIO-FIBULAR
DIASTASIS
Congenital tibio-fibular diastasis was first described by Tuli and Varma in 1972$ since then, several further cases have been described.“,” It is characterized by a clinical triad of congenital talipes equinovarus, diastasis of the ankle and inequality of limb length. There are frequently other abnormalities, either in the same limb, such as an absent or dysplastic first ray, tarsal abnormalities or a hypoplastic femur, or lobster-claw hand, cardiac defects or imperforate anus. Radiographs confirm the diagnosis. BoseZ6 and Jones, Barnes and Lloyd-RobertP consider that the condition results from tibia1 hyoplasia. The child presents with a congenital varus deformity of the foot with a complete but short tibia, revealed by a relatively increased length of the fibula at the level of the ankle and with a lower tibio-fibular diastasis so that the talus subluxates proximally between the tibia and the fibula. Its importance lies in differentiating it from other forms of congenital talipes equinovarus, since treatment needs to be directed to correction of tibio-fibular inequality as well as to the foot deformity, which is very rigid. Tibio-fibular diastasis can be treated by corrective plaster-casting and calcaneal and talo-navicular osteotomy,” or by reconstruction of the ankle mortiseZ3 and correction of equinovarus deformity with later limb lengthening, but the long-term results are not known. Calcaneo-fibular fusion with a Boyd amputation,‘6 or a Syme’s amputation” seems to be a more reliable solution, especially if shortening is predicted to be more than 10 cm at maturity.
6
7
8
9
10. 11
12.
13.
14
15.
16. 17.
18.
19.
20.
21. REFERENCES 1 2.
3. 4. 5.
22.
Bohne W H 0. Root L. Hypoplasia of the fibula. Clin Orthop 1977; 125: 107-112. Hootnick D, Boyd N A, Fixsen .I A; Lloyd-Roberts G C. The natural history and management of congenital short tibia with dysplasia or absence of the fibula. A preliminary report. J Bone Joint Surg Br 1977; 59: 267-271. Coventry M B, Johnson E W. Congenital absence of the fibula. J Bone Joint Surg Am 1952; 34: 941-955. Amstutz H C. Natural history and treatment of congemtal absence of the fibula. J Bone Joint Surg Am 1972, 54: 1349. Lefort J, Carlioz H, Pere C. Aplasies du perone et malformations associees. A propos de 62 cas. Rev Chir Orthop 1976; 62: 621-634.
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23. 24.
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26.
Serafin J. A new operation for congenital absence of the fibula. Preliminary report. J Bone Joint Surg Br 1967; 49: 59-65. Thomas I H, Williams P E The Gruca operation for congemtal absence of the fibula. J Bone Joint Surg Br 1987; 69: 587-592. Wood W L, Zlotsky N, Westin G W. Congenital absence of the fibula. Treatment by Syme’s amputation - indications and technique. J Bone Joint Surg Am 1965; 47: 115991691. Westin G W, Sakai D N. Wood W L. Congenital longitudinal deficiency of the fibula. J Bone Joint Surg Am 1976; 58: 492496. Davidson W H, Bohne W H 0. The Syme amputation m children. J Bone Joint Surg Am 1975; 57: 905-909. Aitken G T Amputation as a treatment for certain lowerextremity congenital abnormalities J Bone Joint Surg Am 1959; 41: 1267-1285. Kruger L M, Talbott R D. Amputation and prosthesis as definitive treatment in congenital absence of the fibula. J Bone Joint Surg Am 1961; 43: 625-642. Herring J A, Barnhill B, Gaffney C. Syme amputation. An evaluation of the physical and psychological function in young patients. J Bone Joint Surg Am 1986: 68, 573-578. Fergusson C M, Morrison J D, Kenwright J. Leg-length inequality in children treated by Syme’s amputation. J Bone Joint Sum Br 1987: 69: 433436. Epps C H, Schmeder P L. Treatment of hemimelias of the lower extremity. Long-term results. J Bone Joint Surg Am 1989; 71: 273-277. Kalamchr A, Dawe R V Congenital deficiency of the tibia. J Bone Joint Surg Br 1985; 67: 581-584. Karchinov K. Congenital diplopodia with hypoplasia or aplasia of the tibia. A report of six cases. J Bone Joint Surg Br 1973; 55: 604611. Jones D, Barnes J. Lloyd-Roberts G C. Congenital aplasia and dysplasia of the tibia with intact fibula. J Bone Joint Surg Br 1978: 60: 31-39. de Sanctis N, Razzano E, Scognamiglio R. Rega A N. Tibia1 agenesis: a new rationale in management of type II - report of three cases with long-term follow-up. J Pediatr Orthop 1980, 10: 1988201 Brown F W. Construction of a knee joint in congenital total absence of the tibia (paraxial hemimelia tibia). J Bone Joint Surg Am 1965; 47: 695-701. Brown F W. Pohnert W H. Construction of a knee ioint in meromelia tibia (congenital absence of the tibia). A 15-year follow-up study. J Bone Jomt Surg Am 1972: 54: 1333. Loder RT, Herring J A. Disarticulation of the knee in children. J Bone Joint Sure Am 1987: 69: 1155-l 160. Tuli S M, Varma B. Cong&tal diastasis of the tibiofibular mortise. J Bone Joint Surg Br 1972: 54: 346-350. Garbarmo J L, Clancy M, Harcke H T, Steel H H, Cowell H R. Congenital diastasis of the inferior tibiofibular joint: a review of the literature and report of two cases. J Pediatr Orthop 1985: 5: 225-228. Onimus M. Laurain J M, Picard F. Congenital diastasis of the inferior tibiofibular joint. J Pediatr Orthop 1990; 10: 175-176. Bose K. Congenital diastasis of the inferior tibiofibular joint. Report of a case. J Bone Joint Surg Am 1976; 58: 886-887.
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