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Minimum Data Set Version 6: FAQs

On Friday 14 November 2014,  the National Joint Registry will launch version 6 of its Minimum Data Set. There will be small changes to what data are collected and how they are recorded on the data entry system.

The changes are in response to feedback from data collection staff and orthopaedic surgeons and have been reviewed extensively by the NJR’s Regional Clinical Coordinators Network and the NJR’s Steering Committee. The improvements aim to reduce the burden of data collection whilst enhancing data quality and the ability of the NJR to analyse the data in ways that more appropriately reflect clinical practice.

Please find on this page asnwers to frequently asked questions about the forthcoming changes:

Where are the new forms?

You can find the new forms on this page >

What is the definition of a revision?

If a joint replacement procedure is carried out and a component is removed, added to or replaced, then this is classified as a revision operation. For knee replacements, this includes secondary resurfacing of the patella, and exchange of polyethylene insert. For hips, this includes PLAD and  exchange of liners.

If no components are removed, added to or replaced for example, a washout for infection, or tendon/ligament repair, then this not a revision but a reoperation. Reoperations are not recorded on NJR.

On all of the revision forms, there are two new check box options for 'Revision Of' and there are two possible answers,  ‘Primary Total Arthroplasty’ and ‘Previous Revision Arthroplasty (excluding excision arthroplasty)’. What is the right thing to do for two-stage revision operations?

If you are completing a stage 2 of a two-stage revision procedure then ignore the fact that a stage 1 of a two-stage revision procedure had been performed on that joint and side. Use the primary procedure preceding the stage 1 to ascertain what should be selected. Base the answer on the procedures that have been performed on the same joint and side.
Example 1
The patient had primary procedure, then a stage 1 revision procedure and then a stage 2 revision procedure. The answer to the 'Revision Of' question should be 'Primary Total Arthroplasty'.
Example 2
The patient had primary procedure, then single-stage revision and then a stage 1 revision procedure and then a stage 2 revision procedure. The answer to 'Revision Of' question should be ‘Previous Revision Arthroplasty (excluding excision arthroplasty)’.

Now that brands of chemical thromboprophylaxis are recorded by type, how do I know which brand fits into which category?

The most commonly used chemical thromboprophylaxis treatments are already noted on the MDSv6 collection forms:

When new drugs come onto the market, the NJR website will be updated to identify which category applies.

If you would like to see a question and answer added to this page please email This page was last updated on 11 November 2014.


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