Orthopedics - Oleksa A.P. 2006

Pathophysiology of Joints
Developmental Defects and Congenital Skeletal Anomalies
Metaphyseal Dysostosis

Metaphyseal dysostosis (dysostosis metaphysaria), a very rare condition, was first described by Jansen in 1934. The Essence of the disease lies in the impairment of enchondral bone growth (metaphyseal chondrodysplasia) resulting from insufficient and abnormal ossification within the metaphyseal regions of long tubular bones, which leads to multiple deformities and stunted longitudinal bone growth. Epiphyseal development and periosteal growth (transverse growth) remain unaffected.

The Etiology of the disease is believed to involve a mutation that can become fixed and transmitted via an Autosomal dominant inheritance pattern, alongside adverse factors (such as intoxication) during Pregnancy that cause damage to the skeletal chondroblastic system.

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Fig. 65. Schmid-type metaphyseal dysostosis in a 6-year-old girl.

Clinically, Two Types of metaphyseal dysostosis are distinguished: the Jansen type and the Schmid type, which differ in their prevalence and severity of involvement.

The Jansen type is generalized in nature with more pronounced manifestations, whereas the Schmid type has a milder course, with less shortening of the limbs and spine and only mildly expressed deformities.

Children with Jansen-type metaphyseal dysostosis are physically underdeveloped and short in stature. Growth retardation begins in the first years of life, progresses, and ceases during Puberty. In adults, the height is 130–135 cm. Examinations reveal that this is due to the shortening of the lower limbs and spine. All segments of the lower extremities are shorter, with thickened and occasionally deformed metaphyses exhibiting varus or valgus deviation (Fig. 65). These children may also present with Clubfoot, metatarsus adductus, or other acquired static deformities. In turn, this leads to The Development of osteoarthritis, pain, restricted joint mobility, and limping.

Similar shortening is observed in all segments of the upper extremities. The hands are well-developed because transverse bone growth is preserved; the fingers are shorter yet, unlike in chondrodystrophy, they do not all share the same length.

The torso is also somewhat shortened, and lateral curvature of the spine can sometimes be detected. Palpation reveals thickening at the junctions of the Ribs and Cartilage. The face and Skull in these children develop normally, and intelligence is preserved. No deviations from the norm are found in Internal Organs or metabolic processes. However, affected children frequently complain of general weakness and slow physical development.

Overview radiographs reveal deformities and thickening of the metaphyseal Regions of the limb bones. The metaphyses are widened and dense in Structure, containing small areas of rarefaction that create a mottled appearance (Fig. 66). The growth plate is thin, and the adjacent layer of the metaphysis is uneven and serrated. The epiphyses are normal. The acetabula are flattened and irregular. The vertebral bodies are smaller and rounded in shape.

Regarding Diagnosis, classic presentations of Jansen-type metaphyseal dysostosis present no difficulties. Chondrodystrophy and chondrodysplasia may have similar clinical manifestations; however, chondrodystrophy presents with typical craniofacial, limb, and spinal changes that are absent in metaphyseal dysostosis. Furthermore, chondrodysplasia is characterized by large areas of rarefaction in the metaphyses resembling enchondromas, whereas dysostosis reveals mottled rarefactions. Enchondral dysostosis is ruled out due to the absence of Changes in the epiphyses of long bones.

Treatment. Upon diagnosing metaphyseal dysostosis, children undergo conservative treatment aimed at preventing the onset and progression of deformities and stimulating growth. Muscle massage, physical therapy (exercise therapy), corrective splints, orthopedic braces, and general strengthening treatments are mandatory. To stimulate growth, Growth Hormone (somatotropin) and a balanced, vitamin-enriched diet are prescribed.

Fig. 66. Schmid-type dysostosis. The metaphyses are uniformly widened and flattened, featuring areas of rarefaction that create a mottled appearance (Sturm, V.A., 1968).

When limb curvatures develop, corrective osteotomies are performed to realign the axis of the segments.

Nowadays, patients have the option to lengthen their limbs using the Ilizarov method—utilizing compression-distraction apparatuses and generating a distraction regenerate following segment osteotomy.