INFANTILE COXA VARA* LI VFLE ROCK, ARKANSAS

Transcription

1 VOL. 115, No. 3 INFANTILE COXA VARA* By JOSEPH D. CALHOUN, M.D.,t and GUY PIERRET, M.D1 LI VFLE ROCK, ARKANSAS D ISEASES in the region of the growing hip alter the mechanics in this area so profoundly, that serious disability usually ensues in childhood or in the adult years unless they are recognized and promptly treated. For this reason, the radiologist is often in a key position for early detection of deforming lesions. Coxa vara is such a deforming lesion and is said to exist when the neck-shaft angle is less than normal. Of the many congenital anomalies of the hip, infantile coxa vara is relatively uncommon, the incidence being approximately i in every 25,000 live births or occurring only once per 14 cases of congenital dislocation of the hip. 2 6 The first report in the literature is usually credited to Fiorani,7 6 who in 1891 described 15 cases of bending of the neck. He felt that this was due to rachitic softening. In 1894, Hofmeister #{176} 6 coined the term coxa vara and Elmslie8 in 1913 described the characteristic triangular fragment. Subsequently, excellent reviews have appeared in the medical literature by such authors as Zadek, Babb et al.,3 and Pylkkanen. 6 However, there has been scant attention given to this condition in the radiologic literature. CLASSIFICATION A. Infantile Coxa Vara B. Congenital Coxa Vara (associated with other anomalies) i. Congenital short femur with coxa vara 2. Coxa vara associated with growth disturbances a. Osteochondrodystrophy (Morquio s disease, Dysplasia epiphysealis multiplex) b. Cleidocranial dysostosis C. Hypothyroidism d. Achondroplasia C. Acquired Coxa Vara I. Epiphyseolysis * From the Department of Radiology, Arkansas Children s Hospital, Little Rock, Arkansas. a. Traumatic b. Slipped capital femoral epiphysis 2. Asceptic necrosis of the femoral head a. Legg-Perthes disease b. Gaucher s disease c. Congenital dislocation of the hip after treatment 3. Sepsis. Rickets. Fibrous dysplasia 6. Fracture a. Traumatic b. Pathologic, e. g., osteogenesis imperfecta ETIOLOGY As seen, there are many types of coxa vara; however the etiology of the infantile type, as in other dysplasias, remains obscure. In fetal life and infancy, growth along the epiphyseal plate of the femur is uneven. The medial portion of the plate matures first, causing a growth spurt medially, resulting in coxa valga of infancy. Shortly thereafter, the greater trochanter or lateral aspect matures and this is followed by a lateral growth spurt which causes a reduction in the valgus of the neck. The interaction between these two different areas determines the neck-shaft angle (Fig. ia), this being 148#{176} at birth and approximately 120#{176}in the adult. Compere et al.,5 have shown experimentally that any disruption between these forces results in serious variations. In their experiments on goats, they found that arrest in the capital femoral t Director of the Department of Radiology. Formerly, Resident in Orthopedics, University of Arkansas School of Medicine and Arkansas Children s Hospital. Present Address: 1021 Breton Lane, Ft. Wayne, Indiana. 6i

2 562 Joseph D. Calhoun and Guy Pierret JULY, 1972 i1ii 11G. I. (A) Right neck-s/taft angle 97#{176}; left neck-shaft angle 130#{176}(normal neck-shaft angle at birth 148#{176};at adulthood 120#{176}). Coxa vara is present when the angle is less than 120#{176}. (B) Right epiphysea/ angle 62#{176}; left epiphyseal angie 25#{176} (normal range of epiphyseal angle is about 20#{176}to,;#{176}). (C) Right acetabu/ar angle i#{176}; left acetabular angle 23#{176}.(D) CE angle of Wiberg. This angle is most useful after the age of 3 or 4 years, when the femoral head is fully ossified and its relationship to the acetabulum is fully established. To measure it, construct a vertical line passing through the edge of the acetabular roof (Point E), and an intersecting line from Point E to the center of the femoral head (Point C). The normal range of the CE angle is 20#{176}-46#{176} (average 36#{176}). Less than 20#{176} is indicative of dysplasia. In diagram D the right CE angle measures 20#{176} and the left CE angle 25#{176}. epiphvsis resulted in a short neck and coxa vara, while arrest in the greater trochanter epiphysis resulted in coxa valga. The blood supply of the proximal femur has been well described by Trueta,2 who found that the head derives its main blood supply from two capsular sources; a large lateral source and a smaller medial source, and that the ligamentum teres did not contribute significantly before the age of 14 years. 0 Many etiologic theories have been proposed, but none have been universally accepted. Camiz,4 from his histologic studies, concluded that the condition was akin to avascular necrosis. The reported cases of familial incidence, the occurrence in twins, 6 7 and the frequent bilateral occurrence has led some to believe that the condition was purely congenital in nature. On the other hand, proponents of a traumatic etiology are numerous.9 3 Pylkkanen s 6 histologic study of biopsies led him to believe that there was a disturbance in the process of ossification in the medial portion of the growth plate resulting in delayed

3 VOL. 115, No. 3 Infantile Coxa Vara 563 growth and that the mechanical forces of weight bearing caused progression of the deformity. Nillsonne 4 and others proposed that the disturbance in ossification and growth of the medial portion was due to some interference with the medial portion of the vascular supply. Amstutz and \Vilson2 postulated that a localized interruption of the blood suppl led to coxa vara, while larger defects were the cause of the congenitally short femur. CLINICAL MATERIAL The records of all patients under our crippled children s program in whom a diagnosis of infantile coxa vara was made in the period of 1954 to 1969 were reviewed. All cases of coxa vara considered to be acquired or having other recognizable associated congenital anomalies were excluded from this report. Nineteen patients met our criteria with the age range being from 2 to 14 years. The usual reported incidence shows a slight female preponderance and approximately 30 per cent of the cases are bilateral.22 In our series, 6 Iatients were FIG. 2. Case. N.F., 4 years of age. (A) Painful limp of left hip at the initial study. (B) After valgus osteotomy there was relief of pain. 1,c.,. Case is. \V.l., II ears of age. (A) Painful limp of the left hip at the initial study. (1?) After 2 valgus osteotomies there was persistent limp with decreased range of motion, but the Pan disa ppea red. male and 13 were female and only 2 (io. per cent) of our patients had both hips affected. A preponderance of Negro patients reflects our clinical population. CLINICAL FINDINGS The mean age of onset of symptoms was 2 years. A painless limp was the presenting symptom in all but 2 children. Case (Fig. 2, 4 and.13) and Case i8 (Fig. 3, 4 and 13) had hip pain on initial visit, but they had relief of pain following surgery. The limp was similar to that found in congenital dislocation, but no telescoping could be elicited. The trochanter on the affected side was usually felt to be elevated. A positive Trendelenburg sign and excessive lumbar lordosis, which is often found, could not be well documented in our cases. Some limitation of motion was usually encountered. Mild decrease in abduction and slight to moderate Hexion contractures were frequently found. In the early age group, a decrease in internal rotation was usually the case. Steindler 9 attributed this finding to the decrease in anteversion that

4 564 Joseph D. Calhoun and Guy Pierret JULY, 1972 FIG. 4. Case I. N.F., 2 years of age. (A) Initial study shows the wide and vertical right epiphyseal plate. The wide epiphyseal plate precedes the development of the triangular fragment. In this case the varus deformity increased from 115#{176}to 102#{176}in II months. (B) The first valgus osteotomy was unsuccessful, but the patient became asymptomatic after the second osteotomy. occurs with varus of the neck. In the older age group, decrease in external rotation was occasionally found in association with secondary changes in the hip joint. Shortening of the affected limb was consistent and varied somewhat with the degree of the varus deformity. The average discrepancy was 1.23 inches. ROENTGENOGRAPHIC FINDINGS The most consistent finding was bending of the neck into a varus position, the severity of which varied directly with the verticality of the epiphyseal plate which we have expressed as the angle of the epiphysis in relation to the horizontal plane (Fig. ib). In Case i (Fig., 4 and B) we were able to observe the progression of the varus angle from 1150 at initial examination to 102#{176} II months later. In addition to a tendency of the epiphyseal line to be in a vertical position, it was consistently widened in relation to the unaffected side. In Case I (Fig. 4z1) and Case 3 (Fig. 4), roentgenographed before the age of 2 years, these findings, along with the varus neck, preceded the appearance of the triangular fragment, suggesting that they are amongst the earliest roentgenologic changes. The metaphyseal-epiphyseal junctions are usually irregular and somewhat fragmented. The femoral necks are usually short and widened in the early stages and narrowed in the older age groups. The characteristic tn angular fragment found at the medial inferior portion of the femoral neck was present in all cases under 9 years of age. In the 5 cases over 9 years, the fragment had already healed and united with the head or neck. It has been observed by others that the smaller the triangular fragment, the greater the degree of varus deformity, and our cases agree with this. In the early stages, the size, shape, and FIG.. Case 3. N.F., 2 years of age. (ii) Initial study. The widened, vertical epiphyseal plate preceded the appearance of the triangular fragment. Note the epiphyseal separation. (B) After surgery the child has pain, limp, and decreased range of motion. Possibly the epiphyseal separation precluded a good result.

5 VOL. 115, No. 3 Infantile Coxa Vara density of the femoral head appeared normal and equal to the unaffected side. In the older untreated cases, however, the head and acetabulum became severely deformed. Ve tested for acetabular dysplasia by measuring acetabular angles (Fig. ic) and CE angles of \Viberg22 (Fig. ID) on all hips. All cases, except i, exhibited some degree of shallowness of the involved acetabulum, but this was only slight and we could not correlate the slight acetabular shallowness with the duration and severity of the coxa vara. According to Wiberg,22 values of the CE angle ofless than 20#{176}are considered indicative ofdysplasia. Only our 2 oldest patients (Case i8, Fig. 3B; and Case 19, Fig. 64) had values of 16#{176} and 6#{176}, respectively. This would suggest that dysplasia occurs in the later stages of the untreated disease. In most cases we found that the femoral shaft on the affected side was more slender than normal. In no patient did we encounter an iliac facet or pseudoarthrosis at the head-neck junction as is occasionally seen in older patients. In i patient (Case 9) the femoral head had changes compatible with aseptic necrosis of the Legg-Perthes type. Johanning reported such cases in a series of 42 patients with infantile coxa vara. In addition to the slenderness of the femoral shaft, we have noted a consistent bone alteration at the junction of the medial cortex of the upper shaft of the femur and the inferior cortex of the neck. The trabecular pattern is altered so that the compression system is thickened. Instead of medial and lateral cortices of the proximal shaft diverging gently from shaft-to-neck, the cortices parallel each other. The thickened medial cortex seems to protrude into the femoral neck and the neck is subsequently bent over the cortical edge. Figure 7 is a line drawing depicting this change. This appearance has been noted in all of our cases (Fig. 8, 4-I) and has not been seen to occur in other forms of coxa vara except 2 cases in which there was trauma to the epiphyseal plate during infancy (Fig., D and FIG. 6. Case 19. N.M., years of age. (A) Initial study. Patient presented with severe arthrosis. CE angle of \Viberg is 12#{176} on right and 6#{176} on left. (B) After bilateral osteotomies there is bilateral subluxation. The patient is lost to follow-up. F). This would seem to be a modeling error resulting from dysplasia or trauma to the femoral neck epiphysis. In our 2 youngest cases (Case i, Fig. 4z1; and Case 3, Fig. z1) who were roentgenographed at about 2 years of age, this appearance and the previously mentioned widening of the epiphyseal plate preceded the appearance of the characteristic triangular fragment. We believe that these 2 findings are reliable indices of the defect at earl age if trauma can be excluded. Greater trochanter development is altered because of change in length and direction of muscle pull and weight stresses. The trochanter epiphysis tends to sit on top of the upper femur rather than on the sloping superolateral surface of the femoral neck. The trochanter is at a more cephalad position than the normal side. In order to complete our evaluation, we reviewed multiple cases of coxa vara which were not considered to be of the infantile

6 66 Joseph D. Calhoun and Guy Pierret JULY, 1972 FIG. 7. Linedrawing depicting: (i) slender proximal femoral shaft; (2) thickened compression system medially; () parallel medial and lateral cortex of the proximal shaft; and () compression system protruding into the femoral neck, with the neck 1)ent over the compression system. type (rickets, Fig. 9z1; epiphysealis multiplex congenita, Fig. 9B; proximal focal femoral deficiency, Fig. 9C; trauma, Fig., D and F; and a case associated with cleidocranial dysostosis, Fig. 9, F and G). We concluded that the radiologic features of these individual conditions manifested themselves readily. In no instance did we encounter a triangular fragment except in a case of cleidocranial dvsostosis (Fig. 9, F and G) which had the typical appearance of infantile coxa vara, but was excluded from this series because of associated deformities. There have been occasional cases of rickets reported as having triangular fragments, but we have seen none. TREATMENT Secondary degenerative changes occur early, leading to arthrosis of the hip joint. If left untreated until adulthood, pseudoarthrosis between the head and neck may ensue, rendering treatment difficult with far less satisfactory results. Therefore, early surgical treatment is in order to achieve a painless and fulk mobile hip without shortening. The aim of treatment is to correct the varus deformity and re-establish the proper length-tension of the abductor muscles. Furthermore, it is imperative that the neck defect heals so that the deformity will not recur. It is felt that if the defective epiphyseal plate can be placed in a horizontal FIG. 8. Initial roentgenograms of additional cases of coxa vara infantum. (A) Case 2. W.V., 2 years. (B) Case. N.F., 3 years. (C) Case 6. N.F., 5 years. (D) Case 7. N.M., years. (E) Case 8. N.M., 6 years. (F) Csae 32. N.F., 7 years. (G) Case 13. N.F., 8 years. (H) Case i. N.M., 9 years. (I) Case i6. N.F., years.

7 VOL. 115, No. 3 Infantile Coxa Vara 567 FIG. 9. Childhood coxa vara of other etiology. (A) Rickets. (B) Dysplasia epiphysealis multiplex. (C) Proximal focal femoral deficiency. (D) Infantile trauma with fracture of femoral neck. (E) Same case as in D after healing. Note the similarity of changes as depicted in Figure 7. (F) Cleidocranial dysostosis. The hip lesion in this case is indistinguishable from other cases of infantile coxa vara. (G) Same case as in F showing absent clavicles. rather than a vertical position, thus converting the forces from shear to compression, the neck defect will heal. Our indications for surgical correction are: an angle of joo or less; a vertical neck defect; or a young child with progression of the varus. Although some mild cases have resolved spontaneously, nonoperative treatment is thought to be ineffective. It is now generally agreed that subtrochanteric osteotomy with metallic internal fixation is the method of choice. Seventeen patients underwent subtrochanteric osteotomies of some type with generally satisfactory results. We had 3 cases (Cases I, 3, and 7) in which there was a recurrence. One of these patients (Case 7) refused further surgery and was subsequently lost to follow-up. One patient (Case i) had a second osteotomy 2 years later with an eventual good result. The third patient (Case 3) had early recurrence and severe secondary changes. She subsequently was re-osteotomized when 9 g years old; however, the results have been poor with a persistent painful limp and decrease in range of motion. Further reconstructive surgery is now being contemplated. One patient (Case 18; Fig. 3z1) developed a pseudoarthrosis at the osteotomy site with subsequent need of reoperation and bone graft. The patient is now i years old. She has no pain, but has residual I inch shortening and moderately severe limitation of motion. One patient (Case i; Fig. 6, 4 and 13) had severe secondary changes when he first sought medical attention at the age of 14 years. He underwent osteotomies bilaterally, without apparent benefit. He subsequently was lost to follow-up before any other reconstructive procedure could be entertained. CONCLUSION Infantile coxa vara is a relatively uncommon disease due to a defective femoral epiphyseal plate. The femoral head and acetab-

8 568 Joseph D. Calhoun and Guy Pierret JULY, 1972 ulum seem essentially normal at birth and during the first few months of life. However, as bone growth and weight bearing occur, the mechanics of the hip joint are so altered that secondary changes and incongruity of the joint will usually occur unless treatment is instituted. A painless limp in a young child is usually the only presenting complaint. Physical findings are meager and not specific. The limp is similar to that found in congenital dislocation of the hip. There might be mild limitation of motion or flexion contracture of the hip. Early roentgenographic examination provides the only means of accurate diagnosis. Important early signs are: i. Significant reduction of neck-shaft angle. 2. Vertical and widened epiphyseal plate. 3. Slender proximal femoral shaft with the medial cortex paralleling the lateral cortex and protruding into the under surface of the femoral neck.. Presence of triangular fragment at the medial inferior portion of the femoral neck (after 2 or 3 years of age).. Alteration in shape and position of the greater trochanter in older children. Severely dysplastic hips ensue when left untreated or when the epiphyseal plate is further damaged surgically. Treatment is by valgus osteotomy aimed at restoring the epiphyseal plate at a more horizontal position, thus eliminating the abnormal shearing forces of weight bearing that affect growth. When this is done without additional surgical damage, the defects usually heal without progressive varus and secondary arthritic changes. Joseph D. Calhoun, M.D. 101 Doctors Building oo South University Little Rock, Arkansas REFERENCES 1. ALMOND, H. G. Familial infantile coxa vara. 7. Bone &JointSurg., 1956,38-B, AMSTUTZ, H. C., and WILSON, P. D. Dysgenesis of proximal femur (coxa vara) and its surgical management. 7. Bone & Joint Surg., 1962, 44-A, I BABB, F. S., GHORMLEY, R. K., and CHAFFER- TON, C. C. Congenital coxa vara. 7. Bone & JointSur., 1949,31-A, CAMIZ, H. Etude compare sur Ia coxa vara dite cong#{233}ni tale et osteochondri te coxa j uvenile. Acta chir. scandinav., 1934, 73, COMPERE, E. L., GARRISON, M., and FAHEY, J. S. Deformities of femur resulting from arrestment of growth of capital or greater trochanteric epiphyses. 7. Bone & Joint Surg., 1940, 22, DUNCAN, G. A. Congenital coxa vara occurring in identical twins. Am. 7. Surg., 1937, 37, I 12-I FIORANI, G. Sopra una forma di zoppicamento. Gas. d. Osp., 1891, 2, 717. Acta orthop. scandinav., 1960, Suppl. 48, GOLDING, C. Congenital coxa vara and short femur. Proc. Roy. Soc. Med., 1938, 32, GOLDING, J. S. R. The Growth Plate and Its Disorders. The Williams & Wilkins Company, Baltimore, I 969, pp. I 55-I HOFMEISTER, F. Coxa vara. Beitr. k/in. C /tir., 1894, 12, 249, Ref. Pylkkanen. 6 II. JOHANNING, K. Coxa vara infantum. Acta orthop. scandinav., 1951, 2!, LEMESURIER, A. B. Developmental coxa vara. 7. Bone & Joint Surg., 1948, 30-B, MAGNOSON, R. Coxa vara infantum. Acta orthop. scandinav., 1953, 23, NILLSONNE, H. On congenital coxa vara. Acta chir. scandinav., 1929, 64, PEABODY, C. W. Subtrochanteric osteotomy in coxa vara. Arch. Surg., 1943, 46, PYLKKANEN, P. V. Coxa vara infantum. Acta orthop. scandinav., 1960, Suppl. 48, ROBERTS, W. M. End result study of congenital coxa vara. South. M. 7., 1950, 43, i8. STALLMAN, J. F. Clinical cases. 7. Bone & Joint Surg., I955,37-B, STEINDLER, A. Kinesiology of the Human Body under Normal and Pathological Conditions. Charles C Thomas, Publisher, Springfield, 111., SZARNAGIEL. Congenital infantile coxa vara. 7. Bone&JointSurg., 1952,34-B, !. TRUETA, J. Normal vascular anatomy of human femoral head during growth. 7. Bone & Joint Surg., 1957,39-B, WIBERG, G. Studies in dysplastic acetabular and congenital subluxation of hip joint. ilcta chir. scandinav., 3939, Suppi. 8, ZADEK, I. Congenital coxa vara. Arch. Surg., 1935,30,

9 This article has been cited by: 1. Adam Greenspan, Javier Beltran. Anomalien der oberen und der unteren Extremit?t [CrossRef] 2.. Congenital Coxa Vara [CrossRef] 3. Donald Resnick, Mark J. Kransdorf. Additional Congenital or Heritable Anomalies and Syndromes [CrossRef] 4. James E. Alexander, Richard L. FitzRandolph, James R. McConnell The limping child. Current Problems in Diagnostic Radiology 16:5, [CrossRef]