Abstract
Introduction and Aims: Union of femoral shaft fractures in a shortened position is a recognised complication of spica cast treatment. Such shortening can only be assessed radiographically until the spica has been removed. The constraints of a spica cast complicate the imaging of the femur and may lead to error in assessing shortening. This study aims to quantify the magnitude of such error for application to clinical practice.
Method: A model for a spiral femoral fracture in a spica cast was devised. Shortening of the femoral segment through telescoping and angulation was controlled with a Wagner lengthening device external to the spica. Shortening from angulation and telescoping were varied and radiographic measurements compared with real measurements. The correlation between true and radiographic shortening of > 2cm was measured with the kappa value.
Results: There was good agreement between radiological and real shortening of > 2cm. Where shortening was present without angulation, the radiological measurement over-estimated the degree of shortening. The error increased with the amount of shortening. Angulation of more than 30 degrees caused the radiological measurement to under-estimate the true amount of segmental shortening.
Conclusion: This study suggests that radiological measurement of femoral shortening in a spica should reliably predict clinically significant shortening when there is less than 30 degrees of fracture angulation.
These abstracts were prepared by Editorial Secretary, George Sikorski. Correspondence should be addressed to Australian Orthopaedic Association, Ground Floor, The William Bland Centre, 229 Macquarie Street, Sydney, NSW 2000, Australia.
None of the authors is receiving any financial benefit or support from any source.
