Changes in biochemical markers after lower limb fractures

Background: The bone remodeling sequence after bone fracture changes the concentrations of biochemical bone markers, but the relationships of fracture size and of healing time to changes in biomarkers are unclear. The present pilot study was undertaken to determine the changes found in serum bone markers after plate osteosynthesis of closed distal tibial and malleolar fractures during a study period of 24 weeks. Methods: We measured tatrate-resistant acid phosphatase (TRACP 5b), collagen type I C-terminal telopeptide (ICTP), bone-specific alkaline phosphatase (bone ALP), osteocalcin (OC), procollagen type I C-terminal propeptide (PICP), procollagen type III N-terminal propeptide (PIIINP), and human cartilage glycoprotein 39 (YKL-40) in 20 patients with lower limb fractures (10 malleolar, 10 tibia). A physical examination and radiographs were completed to assess evidence of union. Results: All malleolar fractures healed within 6 weeks, whereas 2 tibial fractures did not show complete bone healing after 24 weeks. Changes were comparable but more pronounced in the tibia group, and marker concentrations remained increased at the end of study (bone ALP, 86 vs 74 U/L; OC, 14.9 vs 7.7 mu g/L; ICTP: 5.6 vs 3.3 mu g/L at day 84 after osteosynthesis, P < 0.05 in tibia; 80 vs 70 U/L, 8 vs 5.2 mu g/L, and 3.5 vs 3.2 mu g/L, respectively, in the malleolar fracture group). Conclusions: In normal bone healing, changes in bone turnover markers were primarily dependent on the fracture size. Delayed tibia fracture healing may involve a disturbance in bone remodeling. (c) 2007 American Association for Clinical Chemistry