*4 year-old boy with right hip pain and difficulty in walking.
What is the most likely diagnosis?
1. Femoroasetabular impingement
2. Legg-Calve´-Perthes Disease
3. Hip dislocation
4. Osteopetrosis
Answer
Case Discussion:
Plain film demonstrates the asymmetrical femoral epiphyseal size (smaller on the affected side) and increased density of the femoral head epiphysis. MR reveals the bone marrow oedema in the right femoral epiphysis.
Legg-Calve´-Perthes disease (LCPD) is a juvenile osteonecrosis of the femoral head (1). In the acute stages of LCPD the femoral head loses its congruency with the acetabulum and remains deformed depending on the severity of the disease. This deformity is a promoter for premature osteoarthritis in adulthood (2). Plain radiographs are the initial imaging tool for the evaluation of LCPD. The stages of LCPD can be evaluated with x-ray abnormalities. The 4 phases of LCPD are (3);
Stage I
- asymmetric femoral epiphyseal size (smaller on affected side)
- apparent increased density of the femoral head epiphysis
- widening of the medial joint space
- radiolucency of the proximal metaphysis
Stage II
- subchondral lucency
- femoral epiphysis fragments
- femoral head outline is difficult to make out
- mottled density
- thickened trabeculae
Stage III
- re-ossification begins
- shape of the femoral head becomes better defined
- bone density begins to return
Stage IV
- flattening of the articular surface, especially superiorly
- changes depend on severity the femoral head may be nearly normal or may demonstrate
- widening of the head and neck of the femur
Magnetic resonance imaging has been proven to be effective in identifying the proximal femoral anatomy, acetabular labral injury, femoral head and/or acetabular cartilage injury, and the 3-dimensional deformity of the hip (4).
References:
1. Hailer YD, Haag AC, Nilsson O. Legg-Calve´-Perthes Disease: Quality of life, physical activitiy, and behavior pattern. Orthop Clin North Am. 2014 Jan;45(1):87-97.
2. Stulberg SD, Cooperman DR, Wallensten R. The natural history of Legg-Calve-Perthes disease. J Bone Joint Surg Am. 1981;63:1095-1108.
3. Lovell WW, Winter RB, Morrissy RT et-al. Lovell and Winter’s pediatric orthopaedics. Lippincott Williams & Wilkins. (2006) ISBN:0781753589.
4. Leunig M, Werlwn S, Ungersbock A, et al. Evaluation of the acetabular labrum by MR arthrography. J Bone Joint Surg Br. 1997;79:230-234