Evaluation of bone formation marker- Bone Specific Alkaline Phosphatase (BAP) in assessing clinico-radiological union of isolated closed tibial shaft fractures fixed by closed intramedullary nailing

Abstract

Background: Early detection of delayed union or non-union of a fracture is not possible only by clinico-radiological assessment. The changes in the bone turnover markers (BTMs) during fracture healing may lead to early detection of delayed or non-union. Material and Methods: Serial measurement of serum Bone Specific Alkaline Phosphatse (BAP) was undertaken after intramedullary fixation of thirty cases (24 males and 6 females) of isolated closed diaphyseal fractures of tibia in healthy young adults (18-45 years age) with 24 weeks follow-up. The fracture was assessed clinically every four weeks and radiologically at 4, 8, 12, 18 and 24 weeks and RUST scoring was done. Serum BAP levels were measured at 0, 4, 8 and 12 weeks using commercial ELISA method. Results: 27 (90%) patients had bridging callus in 3 or 4 cortices (radiological union) and 3 patients (10%) with delayed union had callus in only two or less cortices at 24 weeks. In patients with normal union peak BAP levels were seen at 8 weeks. BAP levels at 4, 8 and 12 weeks were significantly higher in patients achieving normal union as compared to patients with delayed union (table 3, p= 0003,