Dysplasia epiphysealis multiplex is an uncommon, but not rare developmental abnormality characterized by irregularity in the density and configuration of epiphyses with minimal involvement of the spine.
The condition is not recognizable at birth and often does not present until the ages of 6 or 7 years with bilateral symmetrical abnormalities. The number of epiphyses affected varies from a few to all the major epiphyses.
The regions most prone to involvement being the hips, shoulders, and ankles.
Clinical Features of Dysplasia Epiphysealis Multiplex
There is no obvious dwarfing at birth but stunted growth is noticeable by the age of 2 or 3 years, due mainly to reduced growth of the limbs.
The child is likely to be brought to the hospital because of delay or difficulty in walking. Stiffness or pain in the hips or knees or poor grip with limited finger movement may be presenting symptoms.
When the abnormalities are largely confined to a few large joints, usually the hips, pain or stiffness may not be sufficient to impair function until late childhood or early adult life.
Growth is diminished in affected limbs.
If both upper and lower limbs are involved, the adult appearance simulates achondroplasia but can be distinguished by the absence of abnormality at birth and normal face and skull.
Movements of joints may be affected.
Hip movements, particularly abduction and medial rotation, are limited in almost all patients and may be episodically painful, suggesting a diagnosis of bilateral osteochondritis if other joints are not clinically affected.
Limitation of movement or deformity, or both, may be present at other joints and, when the upper limbs are affected, the digits are short, thick and stubby.
Lab Investigations
The results of biochemical and blood tests are normal.
Imaging
No distinguishing features are present during the first months of life.
The first sign is delayed appearance of ossific centers, that of the femoral head becoming visible between the ages of 1 and 2 years.
The upper femoral epiphysis develops poorly, with irregularly, increased density, and mottling.
Fragmentation, flattening and irregular ossification simulates the changes of osteochondritis similar to Perthes disease but may be distinguished by the slow progression, coxa vara, and radiological changes in other epiphyses.
The acetabulum becomes broad and its roof flat and slightly irregular in conformity with the increasingly abnormal shape of the femoral head. Increasing coxa vara may need to be differentiated from infantile coxa vara, especially in a patient in whom the hips are the main site of involvement.
In dysplasia epiphysealis multiplex, acetabular deformity and distortion of the upper femoral epiphysis are greater than in infantile coxa vara and there is no separate triangular piece of bone at the lower border of the femoral neck.
The femoral condyles are normal at first but later may become irregular with varus or valgus deformity. The hands and feet show typical shortening of metacarpal or metatarsal bones and density of the proximal phalangeal epiphyses.
The distal radial and ulnar epiphyses are hypoplastic and the carpal bones are irregular.
The lateral part of the lower tibial epiphysis may show thinning and the talus may be flat-topped. The vertebrae are unaffected or there may be some irregularity of the upper or lower border with wedging.
Histopathology
It shows irregularity of the growth plates and epiphyses with absent osteoid tissue. The cartilage columns are poorly aligned and bony trabeculae disorganized. The epiphyses have a decreased galactosamine content.
Differential Diagnoses
Perthes Disease
The disease needs to be differentiated from Perthes’ disease (osteochondritis of the upper femoral epiphysis). Pain, limp and limitation of movement of the hips is common to both conditions and the radiological features may be very alike.
The family history, pain in multiple joints, the gradual onset of symptoms with stiffness in the morning and relative shortness of the limbs makes dysplasia epiphysealis multiplex more likely and should alert the surgeon to the need for radiographs of other joints or a full skeletal survey.
The metaphysical involvement and the sclerotic and cystic changes of Perthes disease, and the fact that the epiphyses in bilateral Perthes disease are seldom affected to the same degree at any one time, aids diagnosis.
Infantile coxa vara
This also be confused with dysplasia epiphysealis multiplex as may congenital short femur with coxa vara if it occurs bilaterally.
The absence of gross changes in the vertebrae serves to diagnose the condition from spondyloepiphysial dysplasias and mucopolysaccharidoses and the absence of congenital or early epiphysial stippling and the symmetrical involvement helps to differentiate it from dysplasia epiphysealis punctata.
Treatment of Dysplasia Epiphysealis Multiplex
Osteotomy to correct coxa vara at the hip or varus or valgus deformity at the knee may be needed if function or appearance are sufficiently affected to require surgery but correction made in early life are liable to recur if done before the end of growth.
Episodes of pain in the hip may need treatment by bed rest with traction. Movements and exercises in early life to relieve symptoms and reduce disability.
Limited movements of the digits may warrant metacarpophalangeal or proximal interphalangeal capsulectomy and collateral ligament division to allow the patient to grip.
