Changes in connective tissue metabolism due to bone fractures in children aged 10--14 years. III. Urinary hydroxyproline and glycosaminoglycan excretion following bone fractures treated in different ways.

Urinary hydroxyproline and glycosaminoglycan excretion was studied in the course of fracture healing in twenty 10--14-year-old children with fracture of the femur or of the tibia and fibula. In 11 children reduction and plaster cast were used, in 5 osteosynthesis, and in 4 extension of 6--21 days duration combined with immobilization by plaster cast. In the state of resorption, an increase was observed in the urinary excretion of hydroxyproline and total glycosaminoglycans and in the six glycosaminoglycan fractions studied. As a result of the soft tissue damage accompanying the fracture, the excretion of hyaluronic acid, heparan sulphate, and dermatan sulphate showed the most marked increase. No statistically significant relationship could be demonstrated between the mode of treatment and the amounts of urinary hydroxyproline and glycosaminoglycan, but the stage of resorption was prolonged in the case of treatment with traction. At the beginning of regeneration, a decrease in hydroxyproline excretion and then an increase corresponding to the intensive synthesis of collagen were demonstrated. Glycosaminoglycan excretion during the development of fibrous callus was considerably below the control value. Excretion of the metabolites decreased markedly in the five operated patients. in the case of extension, the stage of regeneration prolonged by 4 to 10 days. In the stage of calcification, urinary hydroxyproline excretion was increased while the excretion of glycosaminoglycan and its fractions was the same as in the controls except in the patients treated with traction. No statistically significant relationship was found between the urinary amounts of hydroxyproline and glycosaminoglycan and the mode of treatment. In the case of traction, fracture repair and the formation of connective tissue callus were prolonged.