Myles Clough, M.D., FRCSC
Access to the major citations databases of the scientific literature is one of the great contributions the Internet has made to the practice of orthopaedics. The Medline database of the US National Library of Medicine (NLM) has been online at the PubMed site for three years now. It has 102 journals exclusively concerned with orthopaedics, hand surgery or orthopaedic sports medicine. There are some publications like the COA Bulletin, which are not in Medline, but most of the major orthopaedic journals are. A properly conducted search of Medline will yield a very valuable review of the literature. Each "citation" in Medline contains the reference, the authors, the abstract (where available) and the keywords used to index the entry.
How does it work? The publishers of the journals supply the reference material and the abstract. Then the librarians at NLM analyse the article and supply the keywords from a specialized vocabulary Medical Subject Headings (MeSH). All of this is entered into a vast database programme. Access to the database is through the PubMed search engine. This takes the words of your search request and analyses them before undertaking the search. The search then produces a list of citations in one of a variety of formats.
As most of us have found, however, using Medline can be frustrating. Either you cannot find anything on the topic or you are buried under a landslide of questionable relevance. It takes years of training to qualify as a Medical Librarian and undertaking searches is a big part of their education. If you are terminally frustrated you can still use the skills of your librarian, but it is possible to train yourself to use the PubMed portal effectively. You won't end your isolation and take full advantage of this valuable service to the medical community unless you do take a little time to train yourself. The CMA also has online access to Medline for its members using the OVID system; and they have a medical librarian on tap to help you so that may be the best way for some.
The first thing to do is decide what type of search you want to undertake. This varies from the highly specific, trying to find the few best papers, to the highly sensitive, trying to get a comprehensive collection of papers on a specific subject. Other searches might be for a paper written by a specific author in a forgotten journal etc. All these are possible if you frame your search correctly.
To do so often requires the uses of the Boolean logic terms OR and AND which mean "either/or" and "together with" respectively. This is not completely intuitive. If you search for "Avascular Necrosis AND osteonecrosis" you might expect to get all the citations for AVN and all those for osteonecrosis. Instead you would only get those citations in which both terms appeared. Conversely if you search for "AVN OR osteonecrosis" you will now get the larger collection in which either term appears (or both). In general, to increase the specificity of your search use AND; to increase the sensitivity use OR. One of the little known wrinkles of the PubMed site is that it automatically assumes the use of AND if you type in more than one word. Thus if you type Forearm Fracture the search engine will assume Forearm AND Fracture - which is likely what you want. The trouble is that you might then miss articles on Radius, Ulna, Monteggia, Galeazzi, Nightstick and Both Bones fractures, because those exact words don't appear in your search. A second wrinkle is that some words are ignored. If you search for Protection against Hip Fracture the term "against" is on the "stoplist" of commonly occurring words which PubMed will ignore. You can look up what the search engine actually uses by pressing the "details" link.
This will show that the database is actually searched for "(protection[All Fields] AND ("hip fractures"[MeSH Terms] OR hip fracture[Text Word]))" Translation - look for citations which contain both the word protection and either contain the words hip fracture or have been indexed by NLM as being about "hip fractures". As you can see (Figure 1) this search strategy can backfire! The first citation is off the topic although you can see why it came up in the search. However, among the 56 citations there are several which are about hip protectors. Perhaps the simplest thing to do to improve the specificity of your search is to find the "best" article on the list, the one which is closest to your subject. Then click on the "Related Articles" link. This will produce a new list of the articles which are most similar to the one you started off with.
There are a number of other strategies which you can learn to use to improve the results from searching. PubMed has produced its own tutorial and the Internet Society of Orthopaedic Surgery and Trauma (ISOST) has a workshop also. The COA will be posting a PubMed Workshop derived from a COA Instructional Course. Taking the time to train yourself and keeping up the skills will pay tremendous dividends.
In summary the Internet allows access to the Medline list of citations in the medical literature, but use of the PubMed search engine can be frustrating. You need to be precise in framing your search and it takes training to use the site effectively. This training is available at many sites on the Internet including some workshops specifically designed for orthopaedic surgeons.
1. PubMed National Library of Medicine http://www.ncbi.nlm.nih.gov/PubMed/ visited Oct 15th 2001
2. MeSH Browser National Library of Medicine http://www.ncbi.nlm.nih.gov/entrez/meshbrowser.cgi visited Oct 15th 2001
3. PubMed Tutorial National Library of Medicine National Library of Medicine http://www.nlm.nih.gov/bsd/pubmed_tutorial/m1001.html visited Oct 15th 2001
4. PubMed Workshop Internet Society of Orthopaedic Surgery and Trauma http://www.orthogate.com/ortho_resources/guide/chpt3_searching/pubmed.html visited Oct 15th 2001