New NJR Minimum Data Set (MDSv8) has gone live

We have been through an exercise to review the developments we need to implement to enable us to update the minimum data set (MDS) and the updated systems and forms have been in use since June 12.

Since the National Joint Registry (NJR) was launched in 2003, we have periodically reviewed and updated the Minimum Data Set (MDS) to ensure that we are capturing data relevant to contemporary joint replacement practice and can achieve our objectives to monitor the quality and safety of orthopaedic services. The previous review of our data collection (MDSv7) took place in 2017/2018 and there have been many progressive advancements in surgical procedures since then, which MDSv8 addresses.

See the left-hand side page menu to access and download MDSv8 forms

We have consulted with relevant orthopaedic specialist societies on these data collection changes and feel that they represent a major step forward in enabling the NJR to fully monitor the outcomes of all joint replacement procedures. The changes are in line with the increased vigilance of implanted devices engendered by the Cumberlege report and the newly developed Medical Device Registries and Outcomes Programme.

All hospital staff involved in entering data into the registry were informed of all the changes well in advance, with checklists supplied to enable them to undertake the necessary development work. Bulk Upload remains available for hip and knee procedures only.

The NJR will also be collecting details for structural implants and augments for all primary procedures, for example:

  • Hips – buttress shim, augment, restrictor, wedge, flange
  • Knees – stems, wedges, blocks, cone, sleeve
  • Shoulder – augment, spacer, block, wedge, collar, segment
  • Elbow – augment, block, wedge, restrictor, sleeve
  • Ankle – augment, block

Whilst many of the structural implants and augments are already on the component database as ‘Accessories’, there will inevitably be many that are not.  We are working closely with industry to ensure that as many of these devices as possible are uploaded in order to minimise the number of ‘Component Requests’. However, we anticipate the time to resolve ‘Component Requests’ may be extended briefly after the switchover.

Changes to NJR Minimum Data Set forms for all joints

  • Collection of second consultant surgeon details in dual consultant operations
  • Change of field ‘gender’ to ‘sex’ with options ‘Male, Female and Indeterminate’
  • Thromboprophylaxis to be sub-divided into ‘in hospital’ and ‘at home’ treatments
  • Components removed sections to have N/A options
  • Addition of fields to capture clinical trial details where a patient has enrolled in a study on all primary forms
  • Collection of data on structural implants or other augments, e.g. stems/wedges/blocks/cone/sleeve
  • Addition of Unified Classification System scoring for periprosthetic fractures on all revision and the new reoperation form

New forms will also be introduced for the following

  • Introduction of a Reoperation other than revision (RO) form to collect:
    • Closed/open reduction of dislocation
    • Fixation of periprosthetic fracture
    • Superficial/deep Debridement and Implant Retention (DAIR)
    • Washout of haematoma
    • Joint Manipulation Under Anaesthesia (MUA e.g. stiff knee)
    • Soft tissue repair/procedure (e.g. ligament/capsule/tendon)
    • Excision of heterotopic bone
    • Excision of excess cement
  • Introduction of Megaprosthesis (M) forms* to collect primary and revision megaprosthetic (endoprosthetic) replacement surgery – *the introduction of these (M forms) will be advised.

Changes to Hip forms

  • Collection of hip hemiarthroplasty procedures (failed hemi will move to a revision form)
  • Addition of acetabular fracture and active infection as indications for surgery
  • Implant fracture as an indication for revision to be sub-divided into ceramic and non-ceramic components
  • Leg length discrepancy and acetabular erosion by hemiarthroplasty to be collected as indications for revision
  • Collection of revision complexity using a score developed by the British Hip Society

Changes to Knee forms

  • Collection of focal knee resurfacing procedures (including location of implant)
  • Addition of focal chondral and osteochondral defects, SONK (spontaneous osteonecrosis of the knee), trauma, metastatic cancer/malignancy and active infection as indications for primary surgery
  • Leg length discrepancy to be collected as an indication for revision
  • Excision arthroplasty to be added as a revision procedure type
  • Collection of revision complexity using a score developed by the British Association for Surgery of the Knee
  • Planned incomplete primary procedure to be added as a primary procedure type with stage two of planned incomplete primary added to procedure types on K2 form
  • Collection of whether a synchronous ACL construction was performed during a primary procedure
  • Tourniquet use in primary and revision procedures to be collected

Changes to Elbow forms

  • Haemophilic arthropathy, metastatic cancer/malignancy and active infection to be added as indications for primary surgery
  • Surgical approach options to be changed to lateral, posterior triceps on, posterior, triceps off and medial
  • Primary total prosthetic replacement to be subdivided into ‘primary total prosthetic replacement including radial head’ and ‘primary total prosthetic replacement without radial head’ 
  • Humeral capitellum hemiarthroplasty to be added as a procedure type
  • Lateral resurfacing to be changed to radio-capitellar arthroplasty including lateral resurfacing
  • Revision procedure types to include partial excision arthroplasty (i.e. removal of radial head prosthesis)
  • Breakage/dissociation of prosthesis and lysis to be added as indications for revision and specify if ulnar/humeral/radial head
  • Aseptic loosening as an indication for revision to be sub-divided to specify ulnar/humeral/radial head

Changes to Shoulder forms

  • Planned incomplete primary procedure to be added as a primary procedure type with stage two of planned incomplete primary added to procedure types on S2 form
  • Glenoid morphology to be collected for primary procedures using a modified Walch classification 

Changes to Ankle forms

  • Indications of high suspicion/low suspicion of infection to be replaced by active infection
  • Addition of periprosthetic fracture as indication for revision.

For further information please contact: NJR Service Desk (

Changes to the data entry system

For all changes in primary and revision hip, knee, ankle, elbow and shoulder joint replacement procedures, click here to see the changes made to reflect developments in clinical practice and enhance NJR data quality.

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