eMedicine Specialties > Radiology > Pediatrics
Legg-Calve-Perthes Disease: Imaging
Updated: May 28, 2008
Radiography
Findings
Legg-Calvé-Perthes disease. Stage II disease. Note the slight widening of the left hip joint, representing a small joint effusion (see also Image 2 in Multimedia). Joint widening can also be secondary to hypertrophy of the cartilage.
Legg-Calvé-Perthes disease. Image shows subchondral sclerosis and radiolucency in the left femoral head (stage II disease). The femoral head is slightly smaller on the left than the right (see also Image 6 in Multimedia).
Legg-Calvé-Perthes disease. Image shows flattening and early fragmentation of the left femoral head with the presence of femoral neck cysts. The femoral head is obviously smaller on the left than on the right (see also Image 10 in Multimedia).
Legg-Calvé-Perthes disease. Image shows loss of structural integrity of the left femoral head. Also note the widening and shortening of the femoral neck, and more importantly, the severe subluxation.
Legg-Calvé-Perthes disease. Plain radiograph in an adult patient with residual coxa magna and plana deformity with superimposed joint changes (compare with the CT scans in Images 16-18 in Multimedia).
Early signs on radiographs include the following (see Images above and Images 1-15, 24 in Multimedia)7 :
- Small femoral epiphysis (96%)
- Sclerosis of the femoral head with sequestration and collapse (82%)
- Slight widening of the joint space caused by thickening of the cartilage, failure of epiphyseal growth, the presence of joint fluid, or joint laxity (60%)
- An absence of destruction of the articular cortex, as occurs in bacterial arthritis (destruction of articular cartilage never occurs in LPD)
Late signs on radiographs include the following:
- Delayed osseous maturation of a mild degree, a radiolucent crescent line representing a subchondral fracture
- Femoral head fragmentation and femoral neck cysts from intramedullary hemorrhage or extension of physeal cartilage into metaphysis, loose bodies, and coxa plana
- Coxa magna, or remodeling of the femoral head, which becomes wider and flatter, similar in appearance to a mushroom
Degree of Confidence
Plain radiographs have a sensitivity of 97% and a specificity of 78% in the detection of LPD.
False Positives/Negatives
Severe osteoarthritis and infective arthritis may mimic LPD.
Computed Tomography
Findings
Legg-Calvé-Perthes disease. Axial nonenhanced CT scan through the hip joints in the same patient as in Image 15 in Multimedia more clearly shows the loss of structural integrity of the right femoral head.
Legg-Calvé-Perthes disease. Nonenhanced axial CT section through the hip joints obtained at a different level in the same patient as in Image 15 in Multimedia. Once again, the scan shows the loss of structural integrity of the right femoral head. Note the acetabular subchondral sclerosis.
Legg-Calvé-Perthes disease. Coronal reconstruction shows flattening, sclerosis, and early fragmentation of the right femoral head (same patient as in Images 15-17 in Multimedia).
Early signs on CT scans include the following (see Images above and Images 16-18 in Multimedia):
- Bone collapse
- Curvilinear zones of sclerosis
- Subtle changes in bone trabecular pattern
- Disruption of an area of condensation of bone formed by a compressive group of trabeculae (abnormal asterisk sign)
Late signs on CT scans include the following:
- Central or peripheral areas of decreased attenuation
- Intraosseous cysts
Coronal reconstructions can show subchondral fractures, subtle buckling, or collapse of the articular surface.
Degree of Confidence
With CT scans, the staging determined on the basis of plain radiographic findings is upgraded in 30% of patients. CT is not as sensitive as nuclear medicine or MRI. CT may be used for follow-up imaging in patients with LPD.
False Positives/Negatives
CT findings of osteoarthritis and infective arthritis may mimic those of LPD.
Magnetic Resonance Imaging
Findings
Legg-Calvé-Perthes disease. Coronal T2-weighted MRIs show irregularity and flattening of cortical margins of the left femoral epiphysis. Also note a mild joint effusion and subluxation and hinge deformity of the left femoral head.
Legg-Calvé-Perthes disease. Coronal T1-weighted MRIs show the loss of normal high signal intensity in the left femoral epiphysis, which now has low signal intensity.
Legg-Calvé-Perthes disease. Axial T1-weighted MRIs through the femoral heads show low signal intensity in the left femoral head.
Legg-Calvé-Perthes disease. Coronal T2-weighted MRI shows irregularity and flattening of cortical margins of the right femoral epiphysis and the loss of normal signal intensity. Also, note a mild effusion in the joint (same patient as in Images 22-24 in Multimedia).
Early in the disease, irregular foci of low signal intensity or linear segments replace the normal high signal intensity of bone marrow in the femoral epiphysis on T1- and T2-weighted images. Other findings include an intra-articular effusion and a small laterally displaced ossification nucleus, labral inversion, and femoral head deformity (see Images above and Images 19-21, 25 in Multimedia).15,16,17,18,19,20
Fat-suppressed or short-tau inversion recovery (STIR) sequences are more accurate than plain radiographs in showing degenerative changes of the articular cartilage. These MRIs demonstrate the influx of fluid into areas of articular cartilage irregularity.
The asterisk sign is defined as findings of areas of low signal intensity on T1-weighted images and high signal intensity on T2-weighted images in marrow. The double-line sign occurs in as many as 80% of patients and represents the sclerotic rim, which appears as a signal void. This sign is demonstrated as a line between necrotic and viable bone edges with a hyperintense rim of granulation tissue.
Jaramillo et al have shown that multipositional MRI with an open magnet was comparable to arthrography for demonstrating containment of the congruency of the articular surfaces of the hip.15 However, in the evaluation of deformity or loss of the spherical nature of the femoral head, open MRI performed less well.
Sebag et al showed dynamic gadolinium-enhanced subtraction MRI to be a simple and promising means of early recognition of ischemia in LPD.16
Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have recently been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. The disease has occurred in patients with moderate to end-stage renal disease after being given a gadolinium-based contrast agent to enhance MRI or MRA scans.
As of late December 2006, the FDA had received reports of 90 such cases of NSF/NFD. Worldwide, over 200 cases have been reported, according to the FDA. NSF/NFD is a debilitating and sometimes fatal disease. Characteristics include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. For more information, see the FDA Public Health Advisory or Medscape.
Degree of Confidence
MRI is as sensitive as isotopic bone scanning, and it allows more precise localization of involvement than conventional radiography. MRI is preferred for evaluating the position, form, and size of the femoral head and surrounding soft tissues.
False Positives/Negatives
The differential diagnosis includes severe osteoarthritis, infective arthritis, and other causes of bone marrow edema and joint effusions.
Ultrasonography
Findings
Ultrasonography is useful in establishing the diagnosis of transient synovitis of the hip and the onset of LPD.
Hip effusion, which results in capsular distention, is accurately documented on sonograms. Sonography allows aspiration of joint fluid for laboratory examination. Together, the results of clinical evaluation, radiography, and sonography determine the need for sonography-guided aspiration. Sonography-guided aspiration allows the selection of only those patients with septic arthritis for surgical drainage and shortens the procedure. Negative sonographic findings allow the exclusion of septic arthritis but not osteomyelitis.
Capsular distention lasting longer than 6 weeks is associated with LPD.
A chronologic, 4-part staging of LPD has been proposed on the basis of the sonographic findings. The stages reflect the degree of flattening and fragmentation and the reconstitution of the femoral head. Thickening of articular cartilage, associated synovitis, and lateral extrusion of the femoral head can be documented. Joint effusion is present in 74% of patients in stages I-II. Lateral extrusion increases from stage II onward until the healing stage.10,11,12,13,14,21
Degree of Confidence
Although not performed routinely, sonographic evaluation of patients with LPD is a simple and standardized procedure that can be useful for staging the disease and monitoring its course. It can also spare the patient from radiation exposure and lower treatment costs. Lateral extrusion and the onset of healing in patients with LPD can be shown earlier with sonograms than with radiographs.
Hip sonography seems to be a reliable method for monitoring the containment of the femoral head in LPD.22
False Positives/Negatives
Changes similar to those of LPD can be found in transient synovitis and other conditions that cause hip joint effusions. Joint effusion is not always present in patients with LDP.
Nuclear Imaging
Findings
Legg-Calvé-Perthes disease. Technetium-99m diphosphonate bone scan shows a photon-deficient defect in the right femoral head.
Legg-Calvé-Perthes disease. Zoomed images of the same patient as in Image 22 in Multimedia show the photopenic defect more clearly.
Legg-Calvé-Perthes disease. Radiograph obtained at the same time as the radionuclide scans in Images 22-23 in Multimedia illustrates the usefulness of isotope bone scans. The radiographic changes of subchondral lucency are subtle.
Technetium-99m diphosphonate uptake depends on the stage of the disease, but it does play a role in the diagnosis. Characteristic features include a photopenic void in proximal femoral epiphyses, as compared with the contralateral side, which usually can be seen by using a pinhole camera with the hip in maximal medial rotation, obviating the need of single-photon emission CT (SPECT).
Scintigraphy may be helpful in early diagnosis. Initially, uptake is decreased in the femoral head because of an interruption in the blood supply. Later, uptake is increased in the femoral head as a result of revascularization, bone repair, and degenerative osteoarthritis. In addition, acetabular activity can be increased with associated joint disease.
Degree of Confidence
The sensitivity of radionuclide scanning in the diagnosis of LPD is 98%, and the specificity is 95%.
False Positives/Negatives
Similar activity patterns may occur with osteoarthritis or infective or inflammatory arthritis. The presence of a large joint effusion can simulate diminished perfusion caused by osteonecrosis.
Angiography
Findings
Angiography is performed only in rare cases. Early in the disease process, opacification of the joint with contrast material can reveal subtle flattening of the chondral surface of the femoral head and widening of the joint space.
Angiographic findings may demonstrate an interruption in the superior capsular arteries and a generalized decrease of blood flow in the affected hip. Later in the disease process, the size and position of sequestered fragments can be identified by the distribution of revascularized osseous segments despite the demonstration of a smooth cartilaginous surface.
Degree of Confidence
Vascular changes in LPD are nonspecific, and angiography is not performed routinely.
More on Legg-Calve-Perthes Disease |
| Overview: Legg-Calve-Perthes Disease |
 Imaging: Legg-Calve-Perthes Disease |
| Follow-up: Legg-Calve-Perthes Disease |
| Multimedia: Legg-Calve-Perthes Disease |
| References |
| « Previous Page | Next Page » |
References
Resnick D. Osteochondroses. In: Bralow L, ed. Bone and Joint Imaging. 2nd ed. Philadelphia: WB Saunders Co;1996: 960-6.
Wheeless CR. Legg Calve Perthes Disease. In: Wheeless' Textbook of Orthopaedics [online]. Available at: http://www.medmedia.com/orthoo/242.htm. Accessed April 18, 2002. [Full Text].
Poul J. Diagnosis of Legg-Calvé-Perthes disease. Ortop Traumatol Rehabil. Oct 30 2004;6(5):604-6. [Medline].
Rosenfeld SB, Herring JA, Chao JC. Legg-calve-perthes disease: a review of cases with onset before six years of age. J Bone Joint Surg Am. Dec 2007;89(12):2712-22. [Medline].
Sharma S, Shewale S, Sibinski M, Sherlock DA. Legg-Calvé-Perthes disease affecting children less than eight years of age: a paired outcome study. Int Orthop. Jan 9 2008;[Medline].
Van Campenhout A, Moens P, Fabry G. Serial bone scintigraphy in Legg-Calvé-Perthes disease: correlation with the Catterall and Herring classification. J Pediatr Orthop B. Jan 2006;15(1):6-10. [Medline].
Meadows C, Monsell F, Ramanan AV. Normal x rays in Perthes disease. Arch Dis Child. Mar 2008;93(3):211. [Medline].
Nelson D, Zenios M, Ward K, Ramachandran M, Little DG. The deformity index as a predictor of final radiological outcome in Perthes' disease. J Bone Joint Surg Br. Oct 2007;89(10):1369-74. [Medline].
Wingstrand H. Significance of synovitis in Legg-Calve-Perthes disease. J Pediatr Orthop B. Jul 1999;8(3):156-60. [Medline].
Zawin JK, Hoffer FA, Rand FF, Teele RL. Joint effusion in children with an irritable hip: US diagnosis and aspiration. Radiology. May 1993;187(2):459-63. [Medline].
Eckerwall G, Hochbergs P, Wingstrand H, Egund N. Sonography and intracapsular pressure in Perthes'' disease. 39 children examined 2-36 months after onset. Acta Orthop Scand. Dec 1994;65(6):575-80. [Medline].
Eggl H, Drekonja T, Kaiser B, Dorn U. Ultrasonography in the diagnosis of transient synovitis of the hip and Legg-Calve-Perthes disease. J Pediatr Orthop B. Jul 1999;8(3):177-80. [Medline].
Naumann T, Kollmannsberger A, Fischer M, et al. Ultrasonographic evaluation of Legg-Calve-Perthes disease based on sonoanatomic criteria and the application of new measuring techniques. Eur J Radiol. Sep 1992;15(2):101-6. [Medline].
Wirth T, LeQuesne GW, Paterson DC. Ultrasonography in Legg-Calve-Perthes disease. Pediatr Radiol. 1992;22(7):498-504. [Medline].
Jaramillo D, Galen TA, Winalski CS. Legg-Calve-Perthes disease: MR imaging evaluation during manual positioning of the hip--comparison with conventional arthrography. Radiology. Aug 1999;212(2):519-25. [Medline].
Sebag G, Ducou Le Pointe H, Klein I. Dynamic gadolinium-enhanced subtraction MR imaging--a simple technique for the early diagnosis of Legg-Calve-Perthes disease: preliminary results. Pediatr Radiol. Mar 1997;27(3):216-20. [Medline].
Hosokawa M, Kim WC, Kubo T, et al. Preliminary report on usefulness of magnetic resonance imaging for outcome prediction in early-stage Legg-Calve-Perthes disease. J Pediatr Orthop B. Jul 1999;8(3):161-4. [Medline].
Song HR, Dhar S, Na JB, et al. Classification of metaphyseal change with magnetic resonance imaging in Legg-Calve-Perthes disease. J Pediatr Orthop. Sep-Oct 2000;20(5):557-61. [Medline].
de Sanctis N, Rega AN, Rondinella F. Prognostic evaluation of Legg-Calve-Perthes disease by MRI. Part I: the role of physeal involvement. J Pediatr Orthop. Jul-Aug 2000;20(4):455-62. [Medline].
de Sanctis N, Rondinella F. Prognostic evaluation of Legg-Calve-Perthes disease by MRI. Part II: pathomorphogenesis and new classification. J Pediatr Orthop. Jul-Aug 2000;20(4):463-70. [Medline].
Doria AS, Cunha FG, Modena M, Maciel R, Molnar LJ, Luzo C, et al. Legg-Calvé-Perthes disease: multipositional power Doppler sonography of the proximal femoral vascularity. Pediatr Radiol. Apr 2008;38(4):392-402. [Medline].
Stücker MH, Buthmann J, Meiss AL. Evaluation of hip containment in legg-calvé-perthes disease: a comparison of ultrasound and magnetic resonance imaging. Ultraschall Med. Oct 2005;26(5):406-10. [Medline].
Sinigaglia R, Bundy A, Okoro T, Gigante C, Turra S. Is conservative treatment really effective for Legg-Calvé-Perthes disease? A critical review of the literature. Chir Narzadow Ruchu Ortop Pol. Nov-Dec 2007;72(6):439-43. [Medline].
Glueck CJ, Tracy T, Wang P. Legg-Calve-Perthes disease, venous and arterial thrombi, and the factor V Leiden mutation in a four-generation kindred. J Pediatr Orthop. Oct-Nov 2007;27(7):834-7. [Medline].
Hubbard AM, Dormans JP. Evaluation of developmental dysplasia, Perthes disease, and neuromuscular dysplasia of the hip in children before and after surgery: an imaging update. AJR Am J Roentgenol. May 1995;164(5):1067-73. [Medline].
Jaramillo D, Kasser JR, Villegas-Medina OL. Cartilaginous abnormalities and growth disturbances in Legg-Calve- Perthes disease: evaluation with MR imaging. Radiology. Dec 1995;197(3):767-73. [Medline].
Joo SY, Lee KS, Koh IH, Park HW, Kim HW. Trochanteric advancement in patients with Legg-Calvé-Perthes disease does not improve pain or limp. Clin Orthop Relat Res. Apr 2008;466(4):927-34. [Medline].
Further Reading
Keywords
Legg-Calvé-Perthes, Legg-Perthes disease, Perthes disease, idiopathic avascular necrosis of the proximal femoral epiphysis, pediatric hip disorder, childhood hip disorder, epiphyseal bone infarction, femoral head infarction, Chandler disease, LPD, LCP
