CONGENITAL ANTERIOR ANGULATION OF THE TIBIABY

J. P. BOUND, H. V. L. FINLAY and F. CLIFFORD ROSEFrom the Paediatric Department, Hillingdon Hospital, Middlesex

(RECEIVED FOR PUBLICATION SEPTEMBER 25, 195 1)

It is proposed in this paper to present two casesof congenital anterior angulation of the tibia.Surprisingly little mention is made in standardpaediatric textbooks of this condition, which isprobably more common than is generally believed.Further, speculation as to its cause may beof value at the present time when antenatalpaediatrics is- arousing such widespread interestand when prevention of certain congenital deform-ities is becoming more than a mere possibility.The vast majority of cases of congenital anterior

angulation of the tibia reported in the literatureoccurred in association with a congenital absenceof the fibula.The earliest reference to congenital anterior

angulation of the tibia which it has been possibleto trace is a report by Proudfoot in 1846 of a' case of compound fracture of the tibia in uteroand congenital talipes talus '. In all probabilitythere was an associated fibular maldevelopmentin this case. On reading the first two paragraphs ofProudfoot's article, which are worthy of quotationin full, one is not surprised that the erroneousdiagnosis of intra-uterine fracture was made.

' Mrs. F., age 28 years, of sanguine temperament,and who has always enjoyed good health, duringthe sixth month of gestation, and of her thirdpregnancy, while attempting to pass through a verynarrow passage, was severely pressed on theabdomen, and immediately experienced a violent painin that region, accompanied with nauseaand faintness.The following day she was threatened with abortion,having pain and some haemorrhage. Thesesymptoms continued for some days, and occasionallyreappeared in a light degree, up to the time of herdelivery, which occurred at full time and wasperfectly natural. At birth, the right foot of thechild (a female) was found permanently extendedand turned upward, pressing against the side of theleg, above the extemal malleolus.The tibia of the same side, about the middle of the

bone, had apparently been the seat of a compoundfracture; the two ends had united, at a slight angleanteriorly, and opposite to this angle there was acicatrix, evidently of some time standing; there was

considerable thickening of the parts near the seatof injury.'

In 1898 Cotton and Chute had gathered togetherand analysed no fewer than 128 cases of congenitalabsence of the fibula. The number of publishedcase reports appearing thereafter in the literaturemay be gauged from the fact that Lapasset andCahuzac in 1935 had found records of 295 casesof congenital absence of the fibula.

Kirmisson (1898) gave a full clinical descriptionof congenital absence of the fibula in his textbook,adding six cases of his own to the literature, whichhe reviewed. Complete absence of the fibulawas more common than partial absence and thecondition was more often unilateral than bilateral.Anterior angulation of the tibia at the junctionof its upper two-thirds and lower third was a usualassociation. The summit of the angle commonlypointed inwards and this, together with retractionof the tendo Achillis, resulted in an equino-valgusposition of the foot. Overlying the angle, a'scar was constantly found. Absence of one ormore toes with the corresponding metatarsalswas common, usually those of the lateral side of thefoot. The whole limb was atrophied to someextent. Other malformations of the affected limbwere not rare; shortening of the thigh, dislocationof the hip and genu valgum. Congenital deform-ities elsewhere in the body had also been associated,such as cleft palate and complete or partial absenceof the radius.

Discussing the pathogenesis, Kirmisson arguedconvincingly against the condition being caused byintra-uterine fractures, under which heading thesecases had previously been described. He thoughtthe most tenable theory was that which supposeda mechanical cause operating during the first twomonths of pregnancy, the result of pressure exertedby a small amniotic sac, often combined with theeffect of amniotic adhesions. He thought theseadhesions were also responsible for the scars.

179

copyright. on M

arch 4, 2021 by guest. Protected by

http://adc.bmj.com

/A

rch Dis C

hild: first published as 10.1136/adc.27.132.179 on 1 April 1952. D

ownloaded from

ARCHIVES OF DISEASE IN CHILDHOODKirmisson also noted the existence of cases of

angulation of the tibia but with an otherwise normalskeleton. In some of these, intra-uterine fracturewas a possibility as a pseudarthrosis was presentat the point of angulation, but he did not thinkthis a reason for rejecting the pressure theory.The prognosis depended on the amount of atrophyof the limb.

Potel (1925) gave a more detailed description ofcases in which both tibia and fibula were present.He did not believe the theory of amniotic com-pression, but thought the deformities were dueto a lesion of the mesoderm during its differenti-ation. The bending was attributed to thelengthening bone being restrained by a lesserdevelopment of the surrounding muscle mass.The scar was simply due to stretching of the skin,or perhaps to amniotic adhesions in some cases.

In his studies on pre-natal lesions of striatedmuscle as a cause of congenital deformity,Middleton (1932, 1934) published three furthercases of congenital angulation of the tibia, one ofwhich was associated with radiological absenceof the fibula. He preferred the term 'congenitaltibial kyphosis . In an attempt to explain theassociated talipes equinus which was apparentlyproduced and maintained by the short calf muscles,Middleton relegated the bony angulation to asecondary place and viewed the muscular shorteningas the primary factor. He supposed that therewas a relative failure during intra-uterine life of thelast stage of growth (i.e. growth in length) of thedeveloping myocyte, leading to a progressiveretraction of the tendo calcaneus, and hence to theproduction of an equinus deformity at the anklejoint. When the ankle joint had become plantar-flexed to its fullest extent, the process of relativeshortening continuing, the strain fell upon the youngshaft of the tibia, which being still cartilaginous,naturally bent at its weakest point which is thejunction of the middle and distal thirds. With theadvent of full ossification of the diaphysis of thetibia the process of progressive deformity came to anend. The dimples were said to mark the spotswhere bursae were likely to develop in later life.Browne (1936) put forward strong arguments

in favour of a mechanical origin for many congenitaldeformities, including ' fracture of the tibia .

He suggested that this was due to the effects ofnormal mechanical and hydraulic pressure inassociation with faulty development of the bones,the weaker leg being bent over the other. Hethought that skin dimples also were the result ofpressure and occurred over bony points in contactwith the uterine wall.Freund (1936) pointed out that most of the

reported cases of congenital absence of the fibulaoccurred in young children who may show totalabsence of the fibula on clinical and radiologicalexanmination, but a few years later present a rudi-mentary fibula in the radiograph. He believedthat the diagnosis of congenital absence of thefibula should not be made before the fifth year oflife at the earliest.

Chapple and Davidson (1941) had their interestaroused in the subject of the relationship betweenfoetal position and certain congenital deformitiesby a male infant who was born with marked lateralbowing of both femora, laterally dislocated hips,shallow acetabula, but a skeleton otherwise normal.When the infant was folded so that each footopposed the apex of the lateral curvature of theother thigh, drawing the legs up tailor-fashion,with each leg meeting the opposite femur at aright angle, it was found that the baby preferredthis position which they termed 'the position ofcomfort'. They stressed the importance of deter-mining the position of comfort as a routine partof the examination of newborn infants, both as ameans of anticipation and prevention of bone andjoint abnormalities and as an aid to the inter-pretation of existing deformities.

Williams (1943) added a further two cases ofcongenital angulation of the tibia to the literature,the first patient survived only 30 minutes andshowed normal fibulae. The second revealedradiological absence of the fibulae and, afteramputation had proved necessary, the distalportions of the limbs were dissected. There wasa solid, strong fibular shaft of fibro-cartilage withabsence of ossification and great predominanceof the fibrous element. Histological examinationof one of the skin dimples showed that only theelastic tissue was slightly deficient and that thedeep layers of the true dermis were in immediateapposition to the periosteum over the bony cortex.Williams still adhered to the theory of a basicmesenchymal defect. This resulted in a limitationof muscle growth, producing the angulation, anda failure of transitional differentiation to fibro-cartilage, cartilage and true bone, causing thefrequently associated defects. He stated thattreatment was difficult and the functional outlookpoor.

In a paper entitled 'Prenatal Bowing andThickening of Tubular Bones with MultipleCutaneous Dimples in Arms and Legs', Caffey(1947) published three cases in which there wassymmetrical lateral bowing of the femora andsymmetrical posterior bowing of the humeri.Distal to the knees and elbows there were similar,but usually unpaired, deformities of the tibiae,

180

copyright. on M

arch 4, 2021 by guest. Protected by

http://adc.bmj.com

/A

rch Dis C

hild: first published as 10.1136/adc.27.132.179 on 1 April 1952. D

ownloaded from

CONGENITAL ANGULATION OF THE TIBIA

radii and ulnae. The fibulae were present inall his cases. Large synmnetrically-placed dimplesoverlay the salient angle in several of the deformedbones of his first two cases. At the level of thebone angulation there was shown radiologicaHlya combination of cortical thickening on the con-cavity with cortical thinning on the convexity,with reduction in the calibre of the medullary cavity.

Caffey explained the cortical hypertrophy asbeing due to failure of absorption from within,and not as representing subperiosteal accretionon the external surface. Clinically there was agradual post-natal regression of the bowing of thebones, especially in the upper limbs, and the corticalthickening tended to lessen. Two of Caffey'scases showed metaphyseal spurs on the medialaspects of the opposing bones at the knees, and heemphasized the similarity to Blount's disease.He particularly drew attention to the occurrenceof co-existing symmetrical bowing of the bones ofthe arms in these cases.

Caffey produced some convincing evidence thatthe skeletal deformities could be explained satis-factorily in large part by assuming that there hadbeen mechanical pressure operating on ectopicfoetal extremities. The deviation from the normalfoetal position needed to be only slight. Heimagined the foetus packed in a cross-leg and cross-arm position, in which each foot pressed on theinternal aspect of the opposite thigh, and each handon the flexor surface of the opposite upper arm.The bone bowed at the site of impact and the skincaught between the summit of the curve and theuterine waHl, underwent pressure atrophy whichproduced a dimple. Caffey considered thatMiddleton's hypothesis did not fit his cases as therewas no evidence of muscle shortening, though hedid not rule out the possibility that transientmuscle shortening of early foetal life could producepersistent curvature of bone.

Recently Duraiswami (1950) has induced variousskeletal abnormalities in the developing chickembryo by the use of insulin. One of his radio-graphs of a 3-week-old chicken shows 'pathologicalfractures' of both tibiae with marked buttressingof the concavities of the bowed bones by sub-periosteal new bone, insulin having been injectedinto the egg on the fourth day. Duraiswami wasof the opinion that these skeletal deformities weredue to an unchecked insulin hypoglycaemia actingon the embryonic cells during the early days ofincubation.

Case ReportsCase 1. RJ., a full-term girl, weighing 8 lb. 14 oz.,

was born in Hillingdon Hospital on September 14, 1950.The mother was 39 years old and had had three normal

children. There was no history of maternal illness duringthe first three months of pregnancy. At the 29th weekof pregnancy a radiograph of the mother's abdomenwas taken because it was thought to be unduly large,and twins were suspected: this revealed bilateralangulation of the humeri, femora, tibiae and fibulae of thefoetus. In this projection no angulation of the radiiand ulnae could be seen. Delivery was normal but theinfant was asphyxiated and died 15 hours later.The limbs showed bilateral talipes equinus and

anterior bowing of the lower legs. There was acutaneous dimple over the site of angulation on theanterior surface of each leg. Palpation revealed thatthe dimple overlay a bony prominence on the anteriorborder of the tibia. Similar dimples overlying bonyprominenceswere pre-SCIIL UH Cilk IUIe11III.Radiography (Dr.

S. A. Maddocks)showed slight corticalthickening postero-medially in the femoraand angulation ofeach tibia at the junc-tion of its upper two-thirds and lower third,while the point offibular angulation wasslightly more proxi-mal. Both tibiae andfibulae showedposterior corticalthickening. Each arm(Fig. 1) showed bonyprojections on theradius and ulna at thesite of a mild angula-tion, with lateralcortical thickening on FiG. 1.-Radiograph (Case 1) of rightthe right side. In this arm, showing bony projections on theprojection no angula- radius and ulna at the site of a mildtion of the humerus angulation.was evident.A post-mortem examination was carried out by

Dr. W. H. A. Picton. One tibia and fibula (Fig. 2)were removed, and a radiograph of the specimen clearlydemonstrated the bony architecture. with thinning of thecortex on the convex surface and thickening on theconcave side (Fig. 3). The necropsy produced evidencethat the baby died of asphyxia: both lungs wereatelectatic and the brain showed subarachnoid haemor-rhages and an area of small haemorrhages in the posteriorpart of the left internal capsule.

Case 2. M.W., a boy, was first seen at HillingdonHospital at the age of 5 months on January 8, 1951,when he was admitted because of collapse of the rightupper lobe of the lung. The mother was a primiparaaged 28 years. During the pregnancy she had noillness but her friends had remarked on the smallnessof her abdomen and she had been able to wear andbutton up her ordinary coat until term. A normal

181

copyright. on M

arch 4, 2021 by guest. Protected by

http://adc.bmj.com

/A

rch Dis C

hild: first published as 10.1136/adc.27.132.179 on 1 April 1952. D

ownloaded from

ARCHIVES OF DISEASE IN CHILDHOOD

deliverv occurred at full term, the birth weight being6 lb. 7 oz.When the infant was examined several deformities

were esvident. Both legs were bowed anteriorly andslightly laterally, more so on the right side, and the feetwere in a mild equinus position, dorsiflexion being

: K:I

NJ.

Ln :.-

FIG. 2.-Post-mortem specimen (Case I) showing tibia and fibula.

Fin. 3.-Radiograph (Case1) of tibia and fibula afterpost-mortem disscion,showing angulation and

bony architecture.

limited to 90'i. Eachleg showed a pair ofcutaneous dimples lyinganteriorly at approxi-mately the same leveljust below the mid-point of the shin, andmuch deeper on theright side. Beneath thetwo dimples on each legwere prominences ofthe anterior borders of

.u

the tibia and fibularespectively. A shallow dimple overlay the head of thefifth metatarsal on each side.The dimples over the extemal epicondyles of the

humeri and the olecranon processes were more markedthan normal. The medial three fingers of both handswere fixed in flexion at the metacarpo-phalangeal andproximal interphalangeal joints, the little finger beingthe most severely affected. The chest showed a marked

pigeon-breast de-formity and bi-lateral triangulargrooves into whichthe elbows andforearms fittedwhen pressed tothe sides. Theskull was plagio-cephalic, the fore-head beingprominent on theright side. Micro-gnathia was amarked featureand there was acleft of the softpalate.Radiography

showed very slightlateral bowing ofthe femora, andthe point of maxi-mal bending of thetibia on both sides Fin. 4.-Radiograph (Case 2) of right tibiawas just below the and fibula at the age of I vear. showingmid-point of the anterior angulation.bone, and was associated with cortical thickeningposteriorly: the anterior prominence was more markedin the fibula than in the tibia (Fig. 4). The left humerusshowed mild posterior bowing in its lower half in alateral view. The skull and spine were normal.Attempts were made to reconstruct the foetal position

of the legs. It was found that they could be folded upeasily over the lower abdomen, so that each foot restedagainst the opposite thigh, without causing any distressto the infant (Fig. 5).

Manipulation and splinting of the fingers have shownan excellent result. After strapping the feet in the earlymonths under the care of Mr. Eyre-Brook, regularmanipulatory moulding of the lower legs and feet hasbeen carried out for eight months with a slightimprovement in the faulty alignment.

Discussion

It will be seen from the foregoing accounts in theliterature that the condition of congenital angulationof the tibia with ossified fibulae is merely a formefruste of the more severe and crippling deformityusually produced by congenital absence of thefibula. It has been shown that radiological absenceof the fibula may merely indicate delay in ossifi-cation of the bone which is still present incartilaginous or fibrous form.

Before considering some of the many theoriesput forward to explain the deformities found inthis condition, Potel's (1925) words may be quoted:'Que le p&one existe ou non, la coudure tibialene saurait avoir deux mecanismes differents et ces

182

copyright. on M

arch 4, 2021 by guest. Protected by

http://adc.bmj.com

/A

rch Dis C

hild: first published as 10.1136/adc.27.132.179 on 1 April 1952. D

ownloaded from

CONGENITAL ANGULATION OF THE TIBIA

affections sont absolument superposables et peuvents'expliquer par un mecanisme identique'.

Although clinically angulation of the tibia maybe the presenting feature, it must also be rememberedthat it may be only one manifestation of a pathology

FIG. 5.-Case 2 at the age of 5 months, showing attempt atreconstruction of foetal position.

affecting to a varying degree the long bones of botharms and legs. This has been emphasized byCaffev and is well shown by our first case. Anytheory as to aetiology must take this fact intoconsideration.

The following theories must be considered.Union of an Intra-uterine Fracture. The frequent

occurrence of the angulation of the tibia as a

bilateral and almost symmetrical deformity byitself renders this theory unlikely, as does thefrequent presence of other associated defects.Examination of the bones at the site of angulationdoes not reveal any sign of a pre-existing fractureeither radiologically or pathologically, althoughthis does not preclude the possibility of fracturehaving occurred very early in foetal life.

Heredity. This does not appear to be an

important factor. In only a few cases has a familialtendency been recorded: in most the conditionappears unexpectedly in otherwise healthy stock.

Intra-uterine Failure of Growth in Length ofDeveloping Muscle Unit. This theory as putforward by Middleton (1932, 1934) has already beendescribed. One of the objections to it is thatcases have been described without talipes, whilein our second case only a mild talipes was present:if the shortening of the calf muscles was sufficientto cause bowing of the tibia, an extreme degreeof talipes equinus would be expected. The theoryoffers no satisfactory explanation for the presenceof the dimples.

Excessive Intra-uterine Pressure. This conception

is not modern but fell into disrepute until recentyears when attention was again drawn to it. Thatexcessive intra-uterine packing can cause foetaldeformities is an attractive theory which canexplain most of the facts. Ideas as to the precisemechanism of the process are vague, but it seemsnot unreasonable to suppose that in certain casesthe growth of the surrounding tissues fails to keeppace with that of the foetus in the amniotic cavity.If this difference in growth is considerable and occursin the early weeks of pregnancy while the foetalbones are still cartilaginous, impairment of thevascular supply to the lateral side of the legs andfeet, with consequent defect of fibular growth andabsence of the lateral toes, might result. At thesame stage, lesser degrees of packing might producebending of the long bones only. On the other hand,pressure of any degree occurring somewhat laterin pregnancy could produce bending of alreadyossifying long bones. Such ' pressure ' occurringearly in pregnancy may be only transient. AsGaenslen (1915) has said, the original deficiencyof amniotic fluid may be more than made up laterin pregnancy. Our first case, if a result of pressure,would be an example of this. The mother'sabdomen was thought to be unduly large when shecame under observation, but at that time thedeformities had already developed. Thus theabsence of a small abdomen in the later monthsdoes not necessarily exclude mechanical pressureas a cause of foetal deformities. The size of amother's abdomen throughout pregnancy, however,depends on so many factors that one should hesitateto ascribe too much significance to this observationin relation to foetal deformities.The multiple deformities of our second case

could be readily explained on the theory thatincreased pressure was exerted on the foetus fromthe early weeks onwards. Thus the tibial bowingwould be due to pressure exerted through the longaxis of the bone, the knee being in contact with theuterine wall and the foot pressed against theopposite thigh. The association of micrognathiaand cleft palate has been attributed to acute flexionof the head on the chest which results in under-development of the mandible: the mouth does notprovide ample space for the tongue and fusionof the palate is prevented (Chapple, 1950).Finally, stiff joints have been thought to be due tointerference with the circulation by increasedpressure (Browne, 1936): the fingers in our casewould be flexed and pressed against the thorax.

Biochemical or Hormonl Influences. Referencehas been made to the studies on the chick embryoby Duraiswami (1950). The production of

183

copyright. on M

arch 4, 2021 by guest. Protected by

http://adc.bmj.com

/A

rch Dis C

hild: first published as 10.1136/adc.27.132.179 on 1 April 1952. D

ownloaded from

184 ARCHIVES OF DISEASE IN CHILDHOOD

deformities of the tibia in some of the insulin-treated group is of great interest but it remains tobe seen to what extent these findings apply tohuman embryology.

In order to throw more light on the aetiologyof this condition, information about the conditionsof pregnancy in further cases is needed. Assuggested by Browne (1951), this study shouldinclude the mother's sensations during pregnancy,the size of her abdomen and the amount of amnioticfluid. In the baby, the distribution of deformitiesand dimples, and an attempt to determine theposition of comfort are important. Enquiry shouldalso be made about illnesses in early pregnancywhich might come to have aetiological importancein relation to a lesion such as that envisaged byMiddleton.

Two cases of congenital bilateral anterior angula-tion of the tibia with fully ossified fibulae aredescribed. In the first case angulation of otherlong bones was present.The more important papers in the literature

are reviewed, most cases being described inassociation with congenital absence of.the fibula.

Cases with congenital bowing or even angulationof the bones of the arms and legs may have tibialangulation as the only obvious clinical feature.The aetiology of the condition is discussed.

We wish to thank Dr. W. Arklay Steel for his advicein the management of the second patient, and we aregrateful to Professor J. L. Henderson and Dr. C. G.Barnes for their many helpful suggestions.The photographs are the work of Mr. E. Stride.

REFERENCESBrowne, D. (1936). Proc. roy. Soc. Med., 29, 1409.

(1951). Brit. med. J., 1, 247.Caffey, J. (1947). Amer. J. Dis. Child., 74, 543.Chapple, C. C. (1950). In Mitchell-Nelson 'Textbook

of Pediatrics,' 5th ed., p. 1469. Philadelphia.and Davidson, D. T. (1941). J. Pediat., 18, 483.

Cotton, T. J. and Chute, A. L. (1898). Trans. Amer.orthop. Ass., 11, 316.

Duraiswami, P. K. (1950). Brit. med. J., 2, 384.Freund, E. (1936). Arch. Surg., Chicago, 33, 349.Gaenslen, F. J. (1915). Amer. J. orthop. Surg., 12, 453.Kirmisson, E. (1898). 'Traite des Maladies Chirurgi-

cales d'origine congenitale,' pp. 551-573. Paris.Lapasset, and Cahuzac, (1935). Rev. Orthop., 22, 110.Middleton, D. S. (1932). Edinb. med. J., 39, 389.

(1934). Ibid., 41, 401.Potel, G. (1925). 'Traite Pratique d'Orthopedie,'

pp. 74-81. Paris.Proudfoot, L. (1846). N. Y. St. J. Med., 7, 199.Williams, E. R. (1943). Brit. J. Radiol., 16, 371. copyright.

on March 4, 2021 by guest. P

rotected byhttp://adc.bm

j.com/

Arch D

is Child: first published as 10.1136/adc.27.132.179 on 1 A

pril 1952. Dow

nloaded from