A NEW METHOD TO DIAGNOSE OCCULT FRACTURES OF CARPAL BONES : THE “QUANTITATIVE X RAY BONE SCAN” – PROSPECTIVE STUDY ON 667 CASES

Abstract

Introduction: Occult fractures of carpal bones are underestimed. To be treated succesfully fractures of the scaphoid must be identified at an early stage. A delay in detection may result in non union. We validated with 3 prospective studies a new tool using scintigraphy : The quantitative Xray bone scan (QRS)

Material and Methods: A previous preliminary prospective study with 60 patients was performed and published to valid the QRS as a step in diagnosis of wrist occult bones fractures equal to RMI. This exam is a bone scan with 2 improvments.

1. 1) A quantification of the fixation spot : If the spot is two times more important on the injuried wrist (than controlateral side) the fracture is sure.

2. 2) If you combine plain Xrays of the the wrist with scintigraphy the fracture is automatically located. This previous report pointed that repeat set of scaphoid views, dynamic and static, Ct scan, proved unsuitable for screening occult fractures of the wrist.

Result: Between november 97 and march 04, 667 patients were enrolled in a prospective continue study. 40% (260/667) of patients with an injury of the wrist with normal X ray sustained an occult fracture. QRS was performed at an average of 17,7 days after the injury and after clinical exam and repeat set of scaphoid view. Scaphoid fractures were most frequent. Fixation was most important if scintigraphy was performed between 11 and 20 days after the injury. Fixation did not depend on age, sex, volume of the bone, and delay (after 15 days).

Discussion: As Dikson, Dias, Thompson, and Kuckla, repeat set of scaphoid view are unable to improve significativally the number of occult fractures of the wrist. RMI as reported by Kuckla can reduce the need for further imaging procedure. RMI and scintigraphy are both the best exam to diagnose surely an occult fracture of the wrist. But QRS does not over diagnose, as RMI, bones fracture’s.

Conclusion: “Plaster cast and wait” is not the treatment for occult carpal bones fracture’s. The quantitative Xray bone scan is able to diagnose such fractures with short delay.