POSTTRAUMATIC DYNAMIC CHANGE OF CARBOXYTERMINAL PROPEPTIDE OF TYPE-I PROCOLLAGEN, ALKALINE-PHOSPHATASE AND ITS ISOENZYMES AS PREDICTORS FORENHANCED OSTEOGENESIS IN PATIENTS WITH SEVERE HEAD-INJURY

Patients suffering from severe head injury and fractures of long bones or large joints often show enhanced osteogenesis, with hypertrophic c allus formation and/or heterotopic ossifications. The advantage of thi s phenomenon is early consolidation of the fractures. An extreme disad vantage is extensive periarticular calcification, resulting in complet e ankylosis of the affected joint. In spite of numerous efforts aimed at clarifying the way in which severe head injury can influence osteog enesis at a distant site, this phenomenon is still not understood. The process, once started, seems irreversible, but if diagnosed in time, could be prevented with non-steroid anti-inflammatory drugs that inhib it development of heterotopic ossifications. The major prerequisite fo r testing this possibility is to define parameters of an early diagnos is of enhanced osteogenesis. Thus, the aim of this study was to test w hether serum values of some parameters related to bone regeneration co uld allow an early prediction of enhanced ossification following bone fracture in patients with severe head injury. Samples of sera were obt ained from three groups of injured patients: fractures of long bones o r large joints only (n = 6), severe head injury only (n = 8), severe h ead injury and fractures of long bones and large joints (n = 7) and fr om a group of apparently healthy volunteers (n = 10). The values for a lkaline phosphatase (ALP), the bone isoenzyme, and the carboxy termina l propeptide of type I procollagen (PICP) were significantly higher (5 -20 times as high) in patients with severe head injury and bone or joi nt fractures than in any other group. Significantly increased concentr ations of PICP were already found in the Ist week after injury, and th ose of ALP and of the bone isoenzyme increased during the 2nd week aft er injury. Results show that these parameters are helpful for an early diagnosis of enhanced osteogenesis and heterotopic ossifications in p atients with severe head injury and bone fractures. Further studies ar e necessary to verify these findings, while analysis of reasons for th e specific patterns of dynamic change of these parameters could lead t o better understanding of the mechanisms underlying the uncontrolled b one formation.