Issues in Orthopaedic Informatics - Defining Orthopaedic Subject Matter
J.F. Myles Clough, M.D., FRCSC
Deciding what to call an orthopaedic subject is a "housekeeping" issue but none the less vital. Orthopaedics is full of synonyms and acronyms. But to search electronically, one needs a unique name or code that can be added to every piece of information that relates to that subject. Only then can one rely on searches to turn up all the information one is looking for. There already are some widely accepted codifications of medical subject matter.
- The Medical Subject Heading (MeSH) system is used by the National Library of Medicine to define the subject matter of medical journals. Internet access to MeSH is at http://www.ncbi.nlm.nih.gov/entrez/meshbrowser.cgi
- The International Classification of Disease (ICD) system is copyrighted to the World Health Authority (WHO). The 9th Revision (ICD-9) has been in use for some time but the 10th revision and its clinical modification (ICD-10-CM) are in the final stages of introduction. The US Center for Disease Control has a download site for ICD including ICD-10-CM at http://www.cdc.gov/nchs/about/otheract/icd9/abticd10.htm
- Systematized Nomenclature of Medicine, better known as SNOMED® is designed by the College of American Pathologists. A Clinical Terms version SNOMED-CT is being prepared in collaboration with the UK National Health Service Executive. SNOMED is for sale and is not freely accessible on the Internet. Details are available at http://www.snomed.org/
- The Orthopaedic Trauma Association published a classific-ation of fractures in Journal of Orthopaedic Trauma Volume 10, Supplement 1, 1996. This illustrated comprehensive classification system is available at http://www.ota.org/compendium/index.htm and may be used (including copying illustrations) without the need to request permission.
| Table # 1 |
ICD-9 Coding of Distal Humerus Fractures
812.4 Lower end, closed
Distal end of humerus
812.40 Lower end, unspecified part
812.41 Supracondylar fracture of humerus
812.42 Lateral condyle
812.43 Medial condyle
812.44 Condyle(s), unspecified
Articular process NOS
Multiple fractures of lower end
Not one of these systems is exactly suited to the needs of orthopaedic informatics. MeSH does not contain the detail needed to describe orthopaedic subjects; for example, it is impossible to use it to describe a meniscus tear. MeSH has the advantage that it is used by medical librarians and is closely integrated with the classification of journal articles. It is therefore the front-runner. The ICD system comes closer to our needs and has the advantage that it can be used to describe procedures as well as conditions. However, it is still not comprehensive (granular) to the degree required. Compare the ICD-9 classification of distal humerus fractures (Table 1) to the OTA classification exemplified in Figure 1. In all likelihood, all the fractures illustrated in Figure 1 would be classified as 812.49 in Table 1. Even worse, there is some doubt about whether some of these fractures should be coded as unspecified articular process fractures (812.44) or multiple fractures of the lower end (812.49).
The OTA classification system itself had some drawbacks, apart from the fact that it does not cover the whole of orthopaedics. Until it is accepted as valuable in the decision-making process when we are treating an injury, it will not be used by everyone. There may still be a long process of "boiling down" this classification system until it is practical and widely used.