Assessment of union in fractures: Role of Serum Alkaline Phosphatase and Ultrasonography.

INTRODUCTION

Fracture union is a fundamental goal in orthopaedics. There is variability in assessment and lack of consensus on reliability of various methods to evaluate progress of union. The purpose of this study was to study the temporal association of non-conventional methods i.e. Serum Alkaline Phosphatase (ALP) and Ultrasound (USG) in assessment of fracture healing with reference to plain radiographs (X-ray).

METHODOLOGY

This was a prospective observational cohort study of 161 adult patients with surgically treated long bone diaphyseal fractures. Plain radiographs, ALP and USG evaluation was done every 6 weekly for 6 months. USG evaluation included assessment of echogenicity and Doppler measurement of Vascular Resistance Index (RI) of callus. Fractures were considered united when X-ray showed bridging callus. ALP and USG changes over the follow-up period were analysed based on the final outcome of fractures.

RESULTS AND CONCLUSION

151 patients showed signs of fracture union at final follow-up. ALP which peaked at 6 weeks in all cases always remained within the laboratory reference range in cases progressing to union; whereas in cases of non-union the levels recorded higher. ALP value was the earliest positive predictor showing progress towards union. Beyond 12 weeks, Hyperechogenicity on Gray scale USG and serial measurement of RI on Doppler USG were found to better confirm progress in fracture union than X-rays. Combined evaluations of ALP and USG appear as promising investigations in assessment of the progress in fracture union.