Arthrography as an Aid to Diagnosis, Prognosis ... - Semantic Scholar

Actaorthop. scand. 51,505-510,1980

ARTHROGRAPHY AS AN AID TO DIAGNOSIS, PROGNOSIS AND THERAPY IN LEGG-CALVa-PERTHES’ DISEASE

Acta Orthop Downloaded from informahealthcare.com by 193.225.92.253 on 05/20/14 For personal use only.

D. H. GERSHUNI”, A. AXER.’

& D. HENDEL’+

Division of Orthopaedic Surgery, University Hospital, University of California Medical Center, San Diego, California, USA and *’ Department of Orthopaedic Surgery and Traumatology, Assaf Harofe Hospital, Zerifin, Israel.

Measurements of head diameter and acetabulum-head quotient (AHQ) were made on the plain radiographs and corresponding arthrograms of 37 consecutive patients with unilateral Legg-CalvC-Perthes’ Disease (L.C.P.D.). Although on plain radiographs the affected osseous femoral capital epiphysis was slightly larger (22) the same size (9) or smaller (6) than that on the normal side, on arthrography the osteochondral head was much larger in 34 and the same size in 3 instances. In 35 cases the arthrograms revealed flattening of the osteochondral head. The AHQ computed from the arthrograms was almost invariably less than that computed from the plain radiographs. Thus the AHQ computed on arthrograms more realistically assessed the almost invariably poor head coverage in L.C.P.D. This, together with signs of flattening, diagnoses the severity of the disease process and helps to differentiate the “head at risk” which requires treatment. During arthrography the degree of abduction-medial rotation of the leg necessary for containment of the flattened protruding head within the acetabulum can be determined, allowing accurate therapy to be planned, be it operative or orthotic.

Key words: arthrography ;diagnosis; Perthes; prognosis; therapy Accepted 20.x.79

The diagnosis of Legg-CalvC-Perthes’ Disease can be made from two adequate radiographs, one taken in the antero-posterior projection and one in the Lauenstein (frog) projection (Figure 1A-B). However, the limitations of this examination are that the sizes of the osteochondral femoral head and acetabulum, their shapes and their relationships to one another cannot be accurately assessed; thus the type and severity of the lesion may be incompletely appreciated. It has been shown that containment treatment of the femoral head gives the best opportunity for the development of a spherical head at the end of the regeneration process (Axer 1965, Harrison 0001-6470/80/030505-06$02.50/0

et al. 1969, Petrie & Bitenc 1971, Axer et al. 1973, Curtis et al. 1974, Brotherton & McKibbin 1977, Salter et al. 1977). The problem is to assess the degree of rotation of the femur (or pelvis) required to achieve adequate containment. This paper describes how these diagnostic, prognostic and therapeutic questions can be resolved by performing bilateral hip arthrography before deciding on treatment. PATIENTS AND METHODS Prior to arthrography, radiographs of the hips of all children were made in the standard neutral and

CC

1980 Munksgaard, Copenhagen

506

D. H. GERSHUNI E T AI,.


A

x 100 =

Abnormal Side Index Normal Side Index

ACETAEULUM-HEAD INDEX

x 100 = Acetabulum4-iead

Quotient

Figure 2. The Acetabulum-Head Quotient.

Figure 1. Six-year-old boy with right-sided LeggCalvk-Perthes’ syndrome in the early fragmentation stage. A and B. Plain radiographs in antero-posterior and Lauenstein projections. The right femoral head appears slightly smaller than that on the left. C. Arthrogram in antero-posterior neutral projection. The right osteochondral head is in fact larger than that on the left and is flattened in the region under the lateral acetabular lip. The head protrudes laterally but still maintains contact with the acetabulum medially. D. Arthrogram with the hips abducted and medially rotated. The osteochondral head will be completely contained by the acetabulum on further slight abduction. Lauenstein positions. Bilateral hip arthrography was performed in 37 consecutive children suffering from unilateral Legg-CalvC-Perthes’ Disease. Radiographs of both hip joints were then taken with the hips in neutral position (Figure 1 C), in an abducted-medially rotated position (Figure 1D)and in the Lauenstein position. Prior measurements of anteversion (Dunlap et al. 1953,

Axer et al. 1972) were helpful in indicating how much medial rotation should initially be performed. The following measurements, calculations and observations were made on both hips of each patient using the plain radiographs and the arthrogram s : 1. The widest diameter of the head on the neutral and Lauenstein views was measured. 2. The acetabulum-head indices and acetabulum-head quotients (Figure 2) (Heyman & Herndon 1950) were measured and calculated on the plain radiographs and on the arthrograms made in the neutral position. 3. Observations were also made on the arthrograms for deformities of the joint contours and pooling of contrast material.

RESULTS The results of the above measurements and calculations are shown in Table 1. The 37 cases of L.C.P.D. were either in the early necrotic (22 cases) or in the later fragmentation stage (15 cases). 1. Head diameters

Radiographs. A difference in the diameters of

the femoral heads between the two sides of 1 mm or more w a s recorded as significant (Schiller & Axer 1972). Of the 37 affected

507

ARTHROGRAPHY IN LEGGCALVfi-PERTHES' DISEASE

femoral heads 22 were larger, 9 were the Arthrogrums. Thirty-four affected femoral same size, 4 were smaller and 2 were 1 mm heads were from 1 to 17 mm larger than the larger in one and 1 mm smaller in the other opposite normal femoral head (Figure 1C); projection as compared with the femoral head the remaining 3 were the same size as the of the opposite unaffected side. opposite unaffected femoral head.

Table 1. Roentgenographic measurements and observations


Stage

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 03. 5 OO3 .6 ***3 7

N N N F F N F N F N N F N F N N F N N N F N F

F F F N N N N F F N N N N F

Head diameter difference in mm Regular Arthrography A.P. Frog A.P. Frog

3 1 0 1 2 0 2 3

2 -1 -0.5 -2 0 -1 0 0 6 0 -1 11 3 10 1 2 4 0 0 1 2 0 1 2

5 0 1 1 2 3 8 4 1 0 0 1 1

0 1 -1 2 0 7 1 0 1 -2 1 0

0 0 -0.5 -1 0 0 0.5 0 6 0 -1 10 2 5 -1 2

7

2 0 0 1.5 1.5 2.5 2 2.5 0

1.5 4

15 7 8 3 5 5 3 3 2 5 4 5 4 6 3 2 5 7 4 12 4.5 8 2 0 1 2

Not possible to measure. ."Healed L.C.P.S. on other side 5 years previously. O o 0 Non-operated cases. N = Necrotic. F = Fragmentation.

0 0 0 1.5 2.5 2 2 4 6 3.5 2 17

6 5 4 5 6 2 3 4 7 3 4.5 5 6 3 3 5 5 4 10 5 3 2 0 1 2

A. H. Q.

Regular 100 100 85 85 100 90 95 97 85 100 100 79 100 89 100 98 99 100 90 100 92 93 88 98 82 78 93 100 100 95 72 91 81 100 100 100 100

Flattening

Arthrography 90 88 79 70 89 72 90 89 0

90 81 75 79 82 93 95 92 82 77 79 89 81 85 92 82 68 94 89 90 76 79 79 78 91 95 98 95

+ + + + + + + + + + + + + + + + + + + + +

+ + + t + + + + + + + + + + +

-

508

D. H. GERSHUNI ET AL.

plain radiograph. (One case could not be measured.)


3. Observation on the arthrograms Flattening of the area of the superior aspect of the osteochondral head underlying the lateral acetabular lip was assessed to be present in 35 of the 37 femoral heads affected by Legg-CalvC-Perthes’ Disease (Figures 1C and 3A). On the abduction and medial rotation arthrogram the flattened region of the head now faced the concave surface of the central area of the acetabulum, and the space between the two articular surfaces thus filled up with contrast material (Figure 3B).

DISCUSSION

Figure 3. Semen-year-old boy with r*ht-sided Legg-CalvbPerthes’ syndrome in the necrotic stage. A . Arthrogram in the antero-posterior neutral projection. The osteochondral femoral head is enlarged, protrudes laterally from the acetabulum and is markedly flattened in the region under the lateral acetabular lip. B. Arthrogram with the hip abducted and medially rotated. The flattened region of the head with the pool of contrast material above it is now rotated into the depths of the acetabulum.

2. Acetabulum-head quotients

In the 37 children with Legg-CalvCPerthes’ Disease the quotient calculated from the arthrographic measurement was less in 34 cases, in one case equal to, and in one greater than the same quotient calculated from the

Arthrography of the hip joints was valuable in the present series firstly because it showed that while the diameter of the osseous femoral head on the affected side, as estimated on the plain radiograph, was slightly greater than that on the opposite side in 22 cases (59 per cent) and in the remaining cases was the same size or smaller, the osteochondral femoral head diameter, as measured by arthrography, revealed that in 34 cases (92 per cent) the affected head was in fact markedly larger than that on the opposite normal side, and in the remaining 3 cases the size of the affected head was the same as the unaffected one. Since the affected femoral head is bigger than normal, it is obvious that the acetabular diameters must also be greater, since the femoral head did not sublux from the acetabulum, contact being maintained between the articular surfaces on the medial side of the joint as demonstrated in Figures 1C-D and 3A-B. Arthrography was also useful in demonstrating that in 35 out of 37 cases the affected femoral head was not only enlarged but was also flattened on the superior aspect of the chondral surface even in the necrotic and fragmentation stages of the disease process. In the neutral arthrogram the


ARTHROGRAPHY IN LEGG-CALVC-PERTHES’ DISEASE

flattened area was situated directly under the lateral acetabular lip (Figures 1C and 3A). Dolman & Bell (1973) and McKibbin & Ralis (1 974) on examining pathological material, and Gross (1977) by direct arthroscopic examination of the hips of children with LeggCalvC-Perthes’ Disease, noted areas of head flattening in all cases and cartilage fibrillation in some portion of the femoral head in twothirds of the hips examined. In two cases Gross recorded a definite defect in the head region opposite the lateral acetabular lip. This is suggestive that it is the lateral acetabular lip which “ploughs” into the articular cartilage of the enlarged femoral head (Linn 1967) and causes the flattening. We have also provided experimental evidence for this possibility in an animal model where, by the induction of a synovitis in the hip joint of immature rabbits, the osteochondral femoral head was stimulated to enlarge. The heads also developed a flattened, degenerative area of cartilage under the lateral aceta wlar lip (Gershuni & Axer 1974, Gershuni et al. 1978, 1979). If the chondral flattening and degeneration is caused by the “ploughing” action of the lateral acetabular lip, it seems logical to remove it from further abnormal stress by rotating it into the depths of the acetabulum proper where regeneration and remodeling of the immature cartilage will occur (Salter et al. 1977, Gershuni et al. 1978, 1979). The necessity for this procedure is assessed by examination of the arthrogram which will demonstrate the presence and severity of the chondral flattening. The acetabulum-head index gives a measure of the containment of the femoral head by the acetabulum, and the acetabulumhead quotient compares the containment of the diseased femoral head with that of the normal side. In 34 out of 37 cases the acetabulum-head quotient measured on the arthrogram was less than that measured on the regular radiograph. Thus it is apparent that femoral head coverage and containment by the acetabulum is rather optimistically assessed when studying plain radiographs. The antero-laterally protruded head cannot be

509

molded by the acetabulum and is thus at risk; attainment of a spherical head at the end of the disease process in such a case is unlikely. A poor result would then be anticipated when no containment treatment is given, be it surgical or orthotic. In two children (nos. 36 and 37, Table 1) no significant antero-lateral protrusion of the head was defined by the arthrogram taken in the neutral position, and the acetabulum-head quotient as calculated from the arthrogram was not significantly different from that calculated on the plain radiograph. These two children have not been treated but are being continually observed and periodically examined radiographically; so far their results have been gratifying. The remaining 34 children, according to the arthrographic assessment, required containment treatment and underwent femoral derotation varus osteotomy (Axer 1965, Axer et a]. 1973, 1979). When containment therapy is decided upon, the degree of abduction and medial rotation of the femur needed to rotate the protruded and flattened segment of the head to within the confines of the acetabulum can be measured by correlating the position of the femur with the arthrographic appearance (Figures 1D and 3B). The correct degree of varus-derotation femoral osteotomy can thus be tailored to the needs of the individual case. Arthrography in these young children has always been performed in the operating theater under general anesthetic. If operation is decided upon, this proceeds with continuation of the same general anesthetic and after redraping the part (Axer et al. 1979). Alternatively another method of containment therapy may be used (Harrison et al. 1969, Petrie & Bitenc 1971). In such a case the knowledge gained from the hip arthrography may be applied in a similar fashion, as when using femoral osteotomy, in more precisely planning treatment. REFERENCES Axer, A. (1 965) Subtrochanteric osteotomy in the treatment of Perthes’ disease. J . Bone Jt Surg. 47-B,489-499.

5 10

D. H. GERSHUNI ET AL.

Axer, A., Halperin, N. & Itzhak, Y. (1972) Anteversion of the femur in Legg-CalvCPerthes’ syndrome. Israel J. med. Sci. 8,


1733-1737.

Axer, A., Schiller, M. G., Segal, D., Rzetelny, V. Gershuni-Gordon, D. H. (1973) Subtrochanteric osteotomy in the treatment of Legg-CalvC-Perthes’s syndrome. Acta orthop. scand. 44, 31-54. Axer, A., Gershuni, D. H., Hendel, D. & Mirovski, Y. (1979) The indications for femoral osteotomy in Legg-CalvC-Perthes’ Syndrome. Clin. Orthop. (In press). Brotherton, B. J. & McKibbin, B. (1977) Perthes’ disease treated by prolonged recumbency and femoral head containment - A long-term appraisal. J. Bone Jt Surg. 59-B, 8-14. Curtis, B. H., Gunther, S. F., Gossling, H. R. & Paul, S. W. (1974) Treatment for LeggPerthes’ disease with the Newington ambulation-abduction brace. J. Bone Jt Surg. 5&A, 1135-1 145. Dolman, C. L. & Bell, H. M. (1973) The pathology of Legg-CalvC-Perthes’ disease. J. Bone Jt Surg. 55-A, 184-188. Dunlap, K., Shands, A. R., Hollister, L. C., Gaul, Y. S. & Streit, H. A. (1953) A new method for determination of torsion of the femur. J. Bone Jt Surg. 35-A, 289-311. Gershuni-Gordon, D. H. & Axer, A. (1974) Synovitis of the hip joint. An experimental model in rabbits. J. Bone J t Surg. S b B , 69-77.

Gershuni, D. H., Axer, A. & Siegel, B. (1978) Experimental synovitis in the hip joint of the rabbit and the resulting biomechanical and

regressive cartilage changes. Trans. Orthop. Res. SOC. 3, 260. Gershuni, D. H., Axer, A. & Siegel, B. (1979) Localized regressive articular cartilage changes in the hip joint of the rabbit following an induced synovitis. Acta orthop. scand. 50, 179-185.

Gross, R. H. (1977) Arthroscopy in hip disorders in children. Orthopaedic Review 9, 43-49. Harrison, M. H. M., Turner, M. H. & Nicholson, F. J. (1969) Coxa Plana. Results of a new form of splinting. J. Bone Jt Surg. 51-A, 1057-1069.

Heyman, C. H. & Hemdon, C. H. (1950) LeggPerthes’ disease. A new method for the examination of the roentgenographic result. J. Bone J t Surg. 32-A, 767-778. Linn, F. C. (1967) Lubrication of animal joints I: The arthrotripsometer. J. Bone Jt Surg. 49-A, 1079-1098.

McKibbin, B. & Ralis, Z. (1974) Pathological changes in a case of Perthes’ disease. J. Bone Jt Surg. 5&B, 438-441. Petrie, J. G. & Bitenc, I. (1971) The abduction weight bearing treatment in Legg-Perthes’ disease. J. Bone J t Surg. 53-B, 54-62. Salter, R. B., Rang, M., Blackstone, I. W., McArthur, R. C., Weighill, F. J., Gygi, A. C. & Stilberg, S. D. (1977) Perthes’ disease: The scientific basis of methods of management and their indications. J. Bone J t Surg. 59-B, 127. Schiller, M. G. & Axer, A. (1972) Legg-CalvO Perthes’ Syndrome (L.C.P.S.). A critical analysis of roentgenographic measurements. Clin. Orthop. 86, 34-42.

Correspondence to: David H. Gershuni, F.R.C.S., F.R.C.S.E., Division of Orthopaedic Surgery, University Hospital, University of California Medical Center, 225 Dickinson Street, San Diego, California, 92103, USA.