Trust, Local Health Board and unit-level activity and outcomes

The observed numbers of revisions of hip and knee replacements for each hospital were compared to the numbers expected given the unit’s case-mix in respect of age, gender and reason for primary surgery. Hospitals with a much higher than expected revision rate for hip and knee replacement have been identified. These hospitals had a revision rate that was above the upper of the 99.8% control limits (these limits approximate to +/-3 standard deviations). We would expect 0.2% (i.e. one in 500) to lie outside the control limits by chance, with approximately half of these (one in 1,000) to be above the upper limit.

When examined over the past ten years of the registry, a total of 39 hospitals reported higher than expected rates of revision for knee replacement and 26 hospitals had higher than expected rates of revision for hip surgery. However, revisions taken only from the last five years of the registry showed only 18 hospitals reporting higher than expected rates for knees, and ten for hips.

The 90-day mortality for primary hip and knee replacement was calculated using the last five years of data for all hospitals by plotting standardised mortality ratios for each hospital against the expected number of deaths.  No hospitals had higher than expected mortality rates for either hip or knee replacement.

Note: The case mix for mortality includes age, gender and ASA grade. Trauma cases have been excluded from both the hip and knee mortality analyses together with hips implanted for failed hemi-arthroplasty or for metastatic cancer (the latter only from November 2014 when recording of this reason began). Also, where both left and right side joints were implanted on the same day, only one side was included in the analysis.

Note: Any units identified as potential outliers in Part Four have been notified. All units are provided with an Annual Clinical Report and additionally have access to an online NJR Management Feedback system.

Important note about the outlier hospitals listed

In earlier annual reports, the NJR reported outlying hospitals based on all cases submitted to the NJR since 1 April 2003. To reflect changes in hospital practices and component use, the NJR now reports outlying hospitals based on the last ten years (13 February 2009 to 14 February 2019) and five years of data (13 February 2014 to 14 February 2019 inclusive, the latter date being when the dataset was cut). These cuts of data exclude the majority of withdrawn outlier implants and metal-on-metal total hip replacements from analysis, and thus better represent contemporary practice.

Outliers for Hip mortality rates since 2014²

None identified

Outliers for Knee mortality rates since 2014²

None identified

Outliers for Hip revision rates, all linked primaries from 2009¹

Ashtead Hospital (Surrey)
Basingstoke and North Hampshire Hospital
BMI Clementine Churchill Hospital (Middlesex)
BMI Esperance (East Sussex)
BMI The Meriden Hospital (West Midlands)
Clifton Park Hospital (North Yorkshire)
Fitzwilliam Hospital (Cambridgeshire)
Homerton University Hospital
KIMS Hospital (Kent)
Milton Keynes Hospital
Musgrove Park Hospital
North Downs Hospital (Surrey)
Northampton General Hospital (Acute)
Nuffield Health Brighton Hospital (East Sussex)
Ormskirk and District General Hospital
Prince Charles Hospital
Salisbury District Hospital
Shepton Mallet Treatment Centre (Somerset)
Southampton General Hospital
Spire Southampton Hospital (Hampshire)
St Richard's Hospital
Sussex Orthopaedic NHS Treatment Centre
Wansbeck Hospital
Watford General Hospital
Weston General Hospital
Wrexham Maelor Hospital

Outliers for Hip revision rates, all linked primaries from 2014²

BMI Bishops Wood Hospital (Middlesex)
Fitzwilliam Hospital (Cambridgeshire)
Milton Keynes Hospital
Nuffield Health Cheltenham Hospital (Gloucestershire)
Ormskirk and District General Hospital
Southampton General Hospital
Spire Hartswood Hospital (Essex)
St Richard's Hospital
Wansbeck Hospital
Weston General Hospital

Outliers for Knee revision rates, all linked primaries from 2009¹

Ashford Hospital
Basingstoke and North Hampshire Hospital
BMI Bishops Wood Hospital (Middlesex)
BMI Goring Hall Hospital (West Sussex)
BMI Princess Margaret (Berkshire)
BMI The London Independent Hospital (Greater London)
BMI The Meriden Hospital (West Midlands)
Broadgreen Hospital
Charing Cross Hospital
County Hospital Louth
Diana Princess of Wales Hospital
Ealing Hospital
Grantham and District Hospital
Guy's Hospital
Heatherwood Hospital
Hinchingbrooke Hospital
Homerton University Hospital
Horton NHS Treatment Centre (Oxfordshire)
King Edward VII Hospital Sister Agnes (Greater London)
Llandough Hospital
Nevill Hall Hospital
New Hall Hospital (Wiltshire)
Nottingham City Hospital
Nuffield Health Chichester Hospital (West Sussex)
Peterborough City Hospital
South Tyneside District Hospital
Southampton General Hospital
Southampton NHS Treatment Centre (Hampshire)
Southmead Hospital
Spire Hull and East Riding Hospital (East Yorkshire)
Spire Southampton Hospital (Hampshire)
St Albans City Hospital
St Mary's Hospital
St Richard's Hospital
Sussex Orthopaedic NHS Treatment Centre
University College Hospital
University Hospital Aintree
West Cumberland Hospital
York Hospital

Outliers for Knee revision rates, all linked primaries from 2014²

Barlborough NHS Treatment Centre (Derbyshire)
BMI Bath Clinic (Avon)
BMI The Meriden Hospital (West Midlands)
BMI The South Cheshire Private Hospital (Cheshire)
Guy's Hospital
Heatherwood Hospital
King Edward VII Hospital Sister Agnes (Greater London)
Leighton Hospital
Lister Hospital
Nuffield Health Chichester Hospital (West Sussex)
Southmead Hospital
Spire Hull and East Riding Hospital (East Yorkshire)
Spire Southampton Hospital (Hampshire)
Springfield Hospital (Essex)
St Mary's Hospital
St Richard's Hospital
Sussex Orthopaedic NHS Treatment Centre
Winfield Hospital (Gloucestershire)

Better than expected performance

This year we have again listed hospitals where revision rates are statistically better than expected. The lists here show units that lie below the 99.8% control limit which also achieved greater than 90% compliance in the 2015/16 NJR data quality audit. Units with lower data quality compliance are automatically excluded from these lists.

Better than expected for Hip revision rates, all linked primaries from 2009¹

Calderdale Royal Hospital
Emersons Green NHS Treatment Centre (Avon)
Ipswich Hospital
Luton and Dunstable Hospital
Musgrave Park Hospital
Nuffield Health Derby Hospital (Derbyshire)
Nuffield Health Exeter Hospital (Devon)
Queen Alexandra Hospital
Queen’s Hospital Burton Upon Trent
Queens Medical Centre Nottingham University Hospital
Royal Derby Hospital
Royal Devon and Exeter Hospital (Wonford)
Royal Stoke University Hospital
Royal Surrey County Hospital
Russells Hall Hospital

Better than expected for Hip revision rates, all linked primaries from 2014²

BMI Alexandra Hospital Cheadle (Cheshire)
Calderdale Royal Hospital
Emersons Green NHS Treatment Centre (Avon)
Ipswich Hospital
Musgrave Park Hospital
Royal Devon and Exeter Hospital (Wonford)
Royal Surrey County Hospital

Better than expected for Knee revision rates, all linked primaries from 2009¹

Bishop Auckland Hospital
BMI Priory Hospital (West Midlands)
City Hospital
Colchester General Hospital
Hexham General Hospital
Ipswich Hospital
Musgrave Park Hospital
Norfolk and Norwich Hospital
North Tyneside General Hospital
Nottingham Woodthorpe Hospital (Nottinghamshire)
Nuffield Health Derby Hospital (Derbyshire)
Nuffield Health Ipswich Hospital (Suffolk)
Princess Alexandra Hospital
Royal Derby Hospital
Stepping Hill Hospital
Worcestershire Royal Hospital
Wrightington Hospital

Better than expected for Knee revision rates, all linked primaries from 2014²

Hexham General Hospital
Musgrave Park Hospital
Stepping Hill Hospital

¹ Date range 13 February 2009 to 14 February 2019 inclusive.
² Date range 13 February 2014 to 14 February 2019 inclusive.

Unit-level activity and outcomes 2018
Clinical activity

Overall in 2018, 145 NHS Trusts and Local Health Boards (comprising 250 separate hospitals) and 181 independent hospitals were open and eligible to report patient procedures to the NJR All units except for two NHS trauma units and one newly opened independent unit submitted data in 2018. The proportion of all hip and knee joint replacements entered into the NJR compared to those entered in HES, is only available by NHS Trust. No data on this is currently available from private providers and figures also exclude units in Northern Ireland as compliance data is not available. Unfortunately finalised compliance figures for Local Health Boards in Wales were not available at time of publication.

• 56.7% of NHS providers reported 95% or more of the joint replacements they undertook
• 30.6% of NHS providers reported between 80% and 95%
• 12.7% of NHS providers reported less than 80%

Of those hospitals submitting data, the proportion of patients who gave permission (consent) for their details to be entered into the NJR were:

NHS hospitals

• 41.1% of NHS hospitals achieved a consent rate of greater than 95%
• 37.9% achieved a consent rate of 80% to 95%
• 21.0% recorded a consent rate of less than 80% 

Independent hospitals

• 63.3% of independent hospitals achieved a consent rate greater than 95%
• 28.3% achieved a consent rate of 80% to 95%
• 8.3% recorded a consent rate of less than 80%

There has been a drop in recorded consent for all submitting units when compared to the previous year, with those achieving a higher than 95% rate falling from 55% to 50%. The proportion of all units achieving a higher than 80% consent rate remains consistent and fell by only 1% to 84% in 2018. 

Similarly, the proportion of entries in which there is significant data to enable the patient to be linked to an NHS number (linkability) are listed.

NHS hospitals

• 83% achieved a proportion of patients with a linkable NHS number greater than 95%
• 15% achieved a proportion of 80% to 95%
• 2% recorded a proportion of less than 80%

Independent hospitals

• 77% achieved a proportion of patients with a linkable NHS number greater than 95%
• 17% achieved a proportion of 80% to 95%
• 6% recorded a proportion of less than 80%

There has been a drop in linkability from 2017 with the percentage of submitting units achieving over 95% in 2018 falling from 85% to 81%.  The proportion achieving a greater than 80% linkability rate is relatively consistent with an overall drop of 1% in 2018.

Note: Independent hospitals might be expected to have lower linkability rates than NHS hospitals, as a proportion of their patients may come from overseas and do not have an NHS number.

Trust, Local Health Board and unit-level activity and outcomes 2018

Part Four of the annual report gives performance and data entry quality indicators for Trusts and Local Health Boards (many of whom comprise more than one hospital) and independent (private) providers in England, Wales, Northern Ireland and the Isle of Man for the 2018 calendar year. Outcomes analysis after hip and knee replacement surgery is also provided for the period 2003 to 2018.